Patent Application
20230364413
The use of electrical stimulation for treatment of medical conditions is well known. One of the most successful applications of modern understanding of the electrophysiological relationship between muscle and nerves is the cardiac pacemaker. Although origins of the cardiac pacemaker extend back into the 1800′s, it was not until 1950 that the first practical, albeit external and bulky, pacemaker was developed. The first truly functional, wearable pacemaker appeared in 1957, and in 1960, the first fully implantable pacemaker was developed.
Many therapeutic applications of electrical stimulation involve the surgical implantation of electrodes within a patient. Recently, minimally invasive electrical stimulators that transmit energy to nerves non-invasively or percutaneously have become more common. A medical procedure is defined as being non-invasive when no break in the skin (or other surface of the body, such as a wound bed) is created through use of the method, and when there is no contact with an internal body cavity beyond a body orifice (e.g., beyond the mouth or beyond the external auditory meatus of the ear). Such non-invasive procedures are distinguished from invasive procedures (including minimally invasive procedures) in that the invasive procedures insert a substance or device into or through the skin (or other surface of the body, such as a wound bed) or into an internal body cavity beyond a body orifice.
Non-invasive medical methods and devices provide a number of advantages relative to comparable invasive procedures. For example, the patient may be more psychologically prepared to experience a procedure that is non-invasive and may therefore be more cooperative, resulting in a better outcome. Non-invasive procedures may avoid damage of biological tissues, such as that due to bleeding, infection, skin or internal organ injury, blood vessel injury, and vein or lung blood clotting. Non-invasive procedures can be generally measurably painless and may be performed without some of the dangers and costs of surgery. They are ordinarily performed even without the need for local anesthesia. Less training may be required for use of non-invasive procedures by medical professionals. In view of the reduced risk ordinarily associated with non-invasive procedures, some such procedures may be suitable for use by the patient or family members at home or by first-responders at home or at a workplace. Furthermore, the cost of non-invasive procedures may be significantly reduced relative to comparable invasive procedures.
In some cases, the patient can apply the stimulator without the benefit of having a trained healthcare provider nearby. An advantage of this “self-stimulation” therapy is that it can be administered more or less immediately when symptoms occur, rather than having to visit the healthcare provider at a clinic or emergency room. A need for such a visit would only compound the aggravation that the patient is already experiencing. Another advantage of the self-stimulation therapy is the convenience of providing the therapy in the patient’s home or workplace, which eliminates scheduling difficulties, for example, when the nerve stimulation is being administered for prophylactic reasons at odd hours of the day. Furthermore, the cost of the treatment may be reduced by not requiring the involvement of a trained healthcare provider.
While minimally invasive nerve stimulators that can be used for self-treatment provide advantages, they also suffer from a number of drawbacks. For example, certain types of nerve stimulators are used to modulate nerves within the patient by positioning the stimulator on an outer skin surface and transmitting the electrical impulses through the skin surface to the target nerve. The position and angular orientation of the device are adjusted about a location on the skin surface until the patient perceives stimulation when current is passed through the stimulator electrodes. The applied current is increased gradually, first to a level wherein the patient feels sensation from the stimulation. The power is then increased, but is set to a level that is less than one at which the patient first indicates any discomfort.
Unfortunately relying solely on the patient’s perception of stimulation is not optimal. In some cases, the patient may “feel” a sensation of stimulation, but may not have positioned the stimulator in the right location to provide optimal stimulation of the underlying nerve. In other cases, the patient may not adjust the level or amplitude of the electrical impulses high enough to sufficiently modulate the target nerve.
What is needed, therefore, are improved systems and methods for minimally invasive nerve stimulators. It would be particularly desirable to provide systems and methods for optimizing the position of such nerve stimulators to provide sufficient modulation of target nerves underlying an outer skin surface of the patient.
Systems and methods are provided for delivering energy impulses (and/or fields) to bodily tissues for therapeutic purposes. In certain aspects, the systems and methods are particularly useful for treating medical conditions wherein the patient uses the devices and methods as self-treatment, without the direct assistance of a healthcare professional.
In one aspect, a method for stimulating a nerve within a patient comprises detecting a target location on an outer skin surface of the patient adjacent to, near, or overlying, a selected nerve and positioning an electrode in contact with the outer skin surface at, or near, the target location. An electrical impulse is then applied from the electrode transcutaneously through the outer skin surface of the patient to the selected nerve to modulate the nerve. Detecting the target location of the underlying nerve allows the patient to position the nerve stimulator in the optimal position for stimulating the nerve.
In certain embodiments, the target location is detected by sensing a heart pulse of the patient. The heart pulse sensor may be any suitable sensor known in the art for detecting the heart pulse of a patient, such as an infrared sensor, optical sensor, tactile sensor, a photoplethysmography (PPG) sensor or the like. The heart pulse sensor may, for example, detect the change in volume of a blood vessel that occurs when the heart pumps blood. Alternatively, the heart pulse sensor may detect vibrations, sounds or other indications that the sensor is located adjacent to, or near, the patient’s heart pulse. The heart pulse sensor may, for example, detect the change in volume of a blood vessel that occurs when the heart pumps blood. Alternatively, the heart pulse sensor may detect vibrations, sounds or other indications that the sensor is located adjacent to, or near, the patient’s heart pulse.
The heart pulse sensor is preferably designed to contact the patient’s outer skin surface and detect a pulse adjacent to, or near the sensor. However, in certain embodiments, the heart pulse sensor may be designed to detect the heart pulse without contacting the skin surface, e.g., through vibration, sound or other detection mechanisms. In these embodiments, sensor may, for example, be located within the stimulator, or within a separate device.
The sensor may be configured to generate an output that indicates the proximity of a heart pulse in the patient. The output may be generated and transmitted via wire, wirelessly, or waveguide, to a control unit within the stimulator, a mobile device, processor, server, or other logic or computing device. This output provides an indication that the electrodes are positioned optimally to modulate the target nerve, e.g., the vagus nerve.
The sensor may be coupled to an indicator within the stimulator, or within a separate device, such as a mobile device (discussed in more detail below). The indicator is configured to generate an alert when the sensor has detected the target nerve. The alert may be, for example, a visual, tactile or audial alert, that provides the user with an indication that the sensor has detected the target location.
In one such embodiment, the sensor comprises a heart pulse sensor that is configured to detect a heart pulse emanating from the carotid artery in the patient’s neck. The vagus nerve is situated within the carotid sheath, near the carotid artery and the interior jugular vein. In this embodiment, the heart pulse sensor may be placed on, or near, the patient’s neck and moved around the target location until the heart pulse is detected. This indicates an optimal position for placement of the electrodes to transmit the electrical impulses through the skin surface to the underlying vagus nerve.
In certain embodiments, the sensor may be configured to detect a magnitude of the heart pulse emanating from the carotid artery. In these embodiments, the sensor may be configured, for example, to only provide an indication that the heart pulse has been detected when the magnitude of heart pulse reaches a threshold level, indicating that the sensor is close to the carotid artery. Alternatively, the sensor may transmit the magnitude of heart pulse detected to a controller or suitable electronics within stimulator, or a separate mobile device.
In certain embodiments, the indicator is configured to transmit an alert that is associated with the magnitude of the heart pulse. For example, the alert may comprise an audible sound that increases in decibel level as the magnitude increase. In another example, the alert may comprise a vibration that increases in intensity or frequency as the magnitude of the heart pulse increases. In yet another example, the alert may comprise a visual signal, such as a blinking light that increases in intensity with heart pulse magnitude, different colored lights associated with threshold magnitudes of heart pulse, or another visual signal, such as bars, lines or other shapes that increase in size (e.g., length or width) with increasing heart pulse magnitude.
The indicator may further be configured to provide a second alert when the magnitude of the heart pulse reaches a threshold level associated with optimal positioning of the sensor and/or the electrodes. For example, if the indicator is providing a blinking light that increases in intensity with heart pulse magnitude, the second alert may be that the blinking light stops blinking and becomes constant, or it changes color (e.g., from yellow to green), or a separate alert is produced, such as a sound, vibration or the like.
In another embodiment, the target location is detected by transmitting an ultrasound signal through the outer skin surface. An ultrasound probe, for example, may be placed in contact with the outer skin surface to transmit the signal therethrough. The high frequency ultrasound waves produce images of structures within the body underneath the skin surface to identify the location of the target nerve.
In another aspect, a device for stimulating a nerve within a patient comprises a sensor for detecting a target location on an outer skin surface of the patient adjacent to, near, or overlying, a selected nerve and an electrode configured for contacting the outer skin surface at, or near the target location. An energy source is coupled to the electrode. The energy source is configured to generate at least one electrical impulse and to transmit the at least one electrical impulse transcutaneously from the electrode through the outer skin surface of the patient to a selected nerve in the patient adjacent to, or near, the target location.
In certain embodiments, the electrical impulse comprises pulses having a frequency of about 1 kHz to about 20 kHz. The electrical impulse may comprise bursts of pulses, with each burst having a frequency of about 1 to about 100 bursts per second and each pulse has a duration of about 50 to about 1000 microseconds in duration. The bursts each comprise about 2 to 20 pulses and the bursts are separated by an inter-burst period that comprises zero pulses.
In other embodiments, the device further comprises a housing, such as a handheld device, that may be operated by the patient. The energy source is housed within the housing and the electrodes are attached to, or incorporated into, the housing.
The housing may contain the electronic components, signal generator and energy source (not shown) that are used to generate the signals that drive electrical impulses through the electrodes. However, in other embodiments, the electronic components that generate the signals may be in a separate housing or device, such as a mobile device. Furthermore, other embodiments may contain a single electrode or more than two electrodes.
In certain embodiments, the housing comprises upper and lower portions and a cover disposed between the upper and lower portions for protecting the electrodes from the external environment. The cover also ensures that electrodes will not contact a patient’s tissue when the device is not intended to be used (e.g., in the event that the device is accidently turned ON and electric current is passed through electrodes when not in use). In certain embodiments, the cover is rotatably coupled to the housing such that it can be moved between a first position, wherein the electrodes are exposed for stimulation, and a second position, wherein the electrodes are housed and protected within the cover.
The housing may comprise a user control panel that includes a number of user controls and/or device status indicators. In alternative embodiments, the controls and status indicators are located on a separate device, such as a mobile device, that is wirelessly (e.g. Bluetooth or the like) coupled to housing.
In other embodiments, the device comprises a patch having at least one adhesive surface for attachment to the outer skin surface of the neck of the patient. The electrodes are housed within the patch. The patch may further comprise a signal generator and an energy source for applying the electrical impulses through the electrodes to the vagus nerve. Alternatively, the patch may include a wireless receiver and associated electronics for wirelessly receiving the electrical impulse and/or the energy from the energy source.
The device may further comprise a controller coupled to the energy source and configured to transmit parameters for the stimulation protocol to the energy source. The controller and/or the energy source may be wirelessly coupled to the electrodes, or each other. Alternatively, the controller and the energy source may be housed within the patch or the handheld device.
In one embodiment, the electrical impulse is transmitted for at least 30 seconds within 4 hours of a commencement of symptoms in the patient. The electrical impulse may be applied in a single dose for a time period of about 30 seconds and about 3 minutes, preferably about 90-150 seconds, or it may be applied in a series of doses each having a time period of about 30 seconds to about 3 minutes, preferably about 90-150 seconds in each dose. The series of doses may be applied every 5 to 30 minutes, preferably every 10 to 20 minutes, and more preferably every 15 minutes, for a period of at least 1 hour, preferably at least 2 hours and more preferably about 3 hours. Each dose may be further applied every 6 to 10 hours for a period of at least 2 to 10 days, preferably about 2 to 5 days.
In another embodiment, the electrical impulse is applied in a first dose for a time period of about 30 seconds and about 3 minutes, preferably about 90-150 seconds and then a second dose for a time period of about 30 seconds and about 3 minutes, preferably about 90-150 seconds. The electrical impulse may be transmitted in a series of first and second doses, wherein the electrical impulse is applied for a time period of about 30 seconds to about 3 minutes (preferably about 90-150 seconds) in each of the first and second doses. The first and second doses may be applied every 10 to 30 minutes (preferably about every 15 minutes) for a period of at least at least 1 hour, preferably at least 2 hours and more preferably about 3 hours. Each dose may be further applied every 6 to 10 hours for a period of at least 2 to 10 days, preferably for about 2 to 5 days.
In certain embodiments, the energy source is wirelessly coupled to the one or more electrodes. In other embodiments, the energy source is coupled to the electrodes directly with electrical connectors. In yet other embodiments, the energy source and the electrodes are housing within a handheld device that can be placed or attached against the outer surface of the patient’s neck.
In one such embodiment, the electrodes are adhered to the outer skin surface of the patient’s neck with a suitable adhesive. This allows the patient to be treated without direct intervention (i.e., holding a device or the electrodes against the patient’s neck during stimulation). The system may further comprise an outer sheath or other wearable device, such as an insulating strip, a collar, or a garment, such as a turtleneck, a scarf or the like, that functions to adhere the electrodes to the neck of the patient. The electrodes may be housed within the wearable device, or positioned between the wearable device and the neck of the patient.
Various technologies for preventing, diagnosing, monitoring, ameliorating, or treating medical conditions, diseases, or disorders, such as replicating pathogens, are more completely described in the following detailed description, with reference to the drawings provided herewith, and in claims appended hereto. Other aspects, features, advantages, etc. will become apparent to one skilled in the art when the description is taken in conjunction with the accompanying drawings.
Hereby, all issued patents, published patent applications, and non-patent publications that are mentioned in this specification are herein incorporated by reference in their entirety for all purposes as if copied and pasted herein, to the same extent as if each individual issued patent, published patent application, or non-patent publication were specifically and individually indicated to be incorporated by reference and copied and pasted herein.
Methods and devices are provided for the non-invasive treatment of diseases and disorders, utilizing an energy source that transmits energy non-invasively to nervous tissue. A medical procedure can be understood as being non-invasive when no break in the skin (or other surface of the body, such as a wound bed) is created through use of the method, and when there is no contact with an internal body cavity beyond a body orifice (e.g., beyond the mouth or beyond the external auditory meatus of the ear). In some ways, such non-invasive procedures can be distinguished from some invasive procedures (including minimally invasive procedures) in that the invasive procedures insert a substance or device into or through the skin (or other surface of the body, such as a wound bed) or into an internal body cavity beyond a body orifice.
In particular, the devices can transmit energy to, or in close proximity to, a selected nerve of the patient in order to temporarily stimulate, block and/or modulate electrophysiological signals in that nerve. In some embodiments, some electrodes applied to the skin of the patient generate currents within the tissue of the patient. This may enable production and application of the electrical impulses so as to interact with the signals of one or more nerves, in order to achieve the therapeutic result.
In some embodiments, methods and devices are specifically designed for the treatment of a patient by stimulation in or around a vagus nerve, with devices positioned non-invasively on or near a patient’s neck. However, it will be recognized that some of the treatment paradigms can be used with a variety of different vagal nerve stimulators, including implantable and/or percutaneous stimulation devices.
It will also be appreciated that some the devices and methods can be applied to other tissues and nerves of the body, including but not limited to other parasympathetic nerves, sympathetic nerves, spinal or cranial nerves, muscles, peripheral nerve stimulation, spinal cord stimulation, neuromuscular electrical stimulation (NMES) or other nerves, such as abdominal aortic plexus, abducens nerve, accessory nerve, accessory obturator nerve, alderman’s nerve, anococcygeal nerve, ansa cervicalis, anterior interosseous nerve, anterior superior alveolar nerve, auerbach’s plexus, auriculotemporal nerve, axillary nerve, brachial plexus, buccal branch of the facial nerve, buccal nerve, cardiac plexus, cavernous nerves, cavernous plexus, celiac ganglia, cervical branch of the facial nerve, cervical plexus, chorda tympani, ciliary ganglion, coccygeal nerve, cochlear nerve, common fibular nerve, common palmar digital nerves of median nerve, deep branch of the radial nerve, deep fibular nerve, deep petrosal nerve, deep temporal nerves, diagonal band of broca, digastric branch of facial nerve, dorsal branch of ulnar nerve, dorsal nerve of clitoris, dorsal nerve of the penis, dorsal scapular nerve, esophageal plexus, ethmoidal nerves, external laryngeal nerve, external nasal nerve, facial nerve, femoral nerve, frontal nerve, gastric plexuses, geniculate ganglion, genital branch of genitofemoral nerve, genitofemoral nerve, glossopharyngeal nerve, greater auricular nerve, greater occipital nerve, greater petrosal nerve, hepatic plexus, hypoglossal nerve, iliohypogastric nerve, ilioinguinal nerve, inferior alveolar nerve, inferior anal nerves, inferior cardiac nerve, inferior cervical ganglion, inferior gluteal nerve, inferior hypogastric plexus, inferior mesenteric plexus, inferior palpebral nerve, infraorbital nerve, infraorbital plexus, infratrochlear nerve, intercostal nerves, intercostobrachial nerve, intermediate cutaneous nerve, internal carotid plexus, internal laryngeal nerve, interneuron, jugular ganglion, lacrimal nerve, lateral cord, lateral cutaneous nerve of forearm, lateral cutaneous nerve of thigh, lateral pectoral nerve, lateral plantar nerve, lateral pterygoid nerve, lesser occipital nerve, lingual nerve, long ciliary nerves, long root of the ciliary ganglion, long thoracic nerve, lower subscapular nerve, lumbar nerves, lumbar plexus, lumbar splanchnic nerves, lumboinguinal nerve, lumbosacral plexus, lumbosacral trunk, mandibular nerve, marginal mandibular branch of facial nerve, masseteric nerve, maxillary nerve, medial cord, medial cutaneous nerve of arm, medial cutaneous nerve of forearm, medial cutaneous nerve, medial pectoral nerve, medial plantar nerve, medial pterygoid nerve, median nerve, meissner’s plexus, mental nerve, middle cardiac nerve, middle cervical ganglion, middle meningeal nerve, motor nerve, muscular branches of the radial nerve, musculocutaneous nerve, mylohyoid nerve, nasociliary nerve, nasopalatine nerve, nerve of pterygoid canal, nerve to obturator internus, nerve to quadratus femoris, nerve to the piriformis, nerve to the stapedius, nerve to the subclavius, nervus intermedius, nervus spinosus, nodose ganglion, obturator nerve, oculomotor nerve, olfactory nerve, ophthalmic nerve, optic nerve, otic ganglion, ovarian plexus, palatine nerves, palmar branch of the median nerve, palmar branch of ulnar nerve, pancreatic plexus, patellar plexus, pelvic splanchnic nerves, perforating cutaneous nerve, perineal branches of posterior femoral cutaneous nerve, perineal nerve, petrous ganglion, pharyngeal branch of vagus nerve, pharyngeal branches of glossopharyngeal nerve, pharyngeal nerve, pharyngeal plexus, phrenic nerve, phrenic plexus, posterior auricular nerve, posterior branch of spinal nerve, posterior cord, posterior cutaneous nerve of arm, posterior cutaneous nerve of forearm, posterior cutaneous nerve of thigh, posterior scrotal nerves, posterior superior alveolar nerve, proper palmar digital nerves of median nerve, prostatic plexus (nervous), pterygopalatine ganglion, pudendal nerve, pudendal plexus, pulmonary branches of vagus nerve, radial nerve, recurrent laryngeal nerve, renal plexus, sacral plexus, sacral splanchnic nerves, saphenous nerve, sciatic nerve, semilunar ganglion, sensory nerve, short ciliary nerves, sphenopalatine nerves, splenic plexus, stylohyoid branch of facial nerve, subcostal nerve, submandibular ganglion, suboccipital nerve, superficial branch of the radial nerve, superficial fibular nerve, superior cardiac nerve, superior cervical ganglion, superior ganglion of glossopharyngeal nerve, superior ganglion of vagus nerve, superior gluteal nerve, superior hypogastric plexus, superior labial nerve, superior laryngeal nerve, superior lateral cutaneous nerve of arm, superior mesenteric plexus, superior rectal plexus, supraclavicular nerves, supraorbital nerve, suprarenal plexus, suprascapular nerve, supratrochlear nerve, sural nerve, sympathetic trunk, temporal branches of the facial nerve, third occipital nerve, thoracic aortic plexus, thoracic splanchnic nerves, thoraco-abdominal nerves, thoracodorsal nerve, tibial nerve, transverse cervical nerve, trigeminal nerve, trochlear nerve, tympanic nerve, ulnar nerve, upper subscapular nerve, uterovaginal plexus, vagus nerve, ventral ramus, vesical nervous plexus, vestibular nerve, vestibulocochlear nerve, zygomatic branches of facial nerve, zygomatic nerve, zygomaticofacial nerve, or zygomaticotemporal nerve.
In some embodiments, a time-varying magnetic field, originating and confined to the outside of a patient, generates an electromagnetic field and/or induces eddy currents within tissue of the patient. In some embodiments, electrodes applied to the skin of the patient generate currents within the tissue of the patient.
The methods and devices disclosed herein can be used to prevent, diagnose, monitor, ameliorate, or treat a medical condition, a disease, or a disorder of a patient, such as a mammal, such as an animal, such as a human, whether male or female, whether infant, child, adult, or elderly, or others.
For example, the devices can be configured to prevent, diagnose, monitor, ameliorate, or treat a neurological condition, such as epilepsy, headache/migraine, whether primary or secondary, whether cluster or tension, neuralgia, seizures, vertigo, dizziness, concussion, aneurysm, palsy, Parkinson’s disease, Alzheimer’s disease, post-traumatic stress disorder (PTSD) or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the medical devices can be configured to prevent, diagnose, monitor, ameliorate, or treat conditions associated with replicating pathogens. The replicating pathogen may include a bacteria, fungi, protozoa, worm, infectious protein (e.g., prion) or a virus, such as an RNA virus. In one particular embodiment, the virus comprises a virus that contains a sensitizing and/or allergenic protein or other molecule that triggers an allergic or inflammatory response in the patient, such as a virus in the coronaviridae or coronavirus family (e.g., COVID 19). The methods and systems of the present invention reduce the expression of inflammatory mediators that are elevated in ARDS and other inflammatory disorders, thereby ameliorating the overactivity of the immune reaction in patient’s suffering from certain disorders associated with replicating pathogen. This therapy provides potent anti-inflammatory activity without the negative side effect of conventional immune suppression techniques and drugs, such as steroids. In addition, the methods and systems of the present invention decrease the magnitude of constriction of bronchial smooth muscle, thereby improving the patient’s breathing in situations involving shortness of breath and impaired oxygen saturation, such as ARDS caused by certain replicating pathogens (e.g., COVID 19).
For example, the medical devices can be configured to prevent, diagnose, monitor, ameliorate, avert or treat a stroke and/or transient ischemic attack, to ameliorate or limit the effects of an acute stroke or transient ischemic attack, and/or to rehabilitate a stroke patient.
For example, the medical devices can be configured to prevent, diagnose, monitor, ameliorate, or treat neurological, neuropsychological, or neuropsychiatric activity, such as a modulation of neuronal function or processing to affect a functional outcome. The modulation of neuronal function can be useful with regard to diagnosing, monitoring, preventing, treating, or ameliorating neurological, psychiatric, psychological, conscious state, behavioral, mood, or thought activity. For example, this activity can manifests itself in a form of a disorder, such as attention or cognitive disorders (e.g., Autistic Spectrum Disorders), mood disorder (e.g., major depressive disorder, bipolar disorder, dysthymic disorder), anxiety disorder (e.g., panic disorder, posttraumatic stress disorder, obsessive-compulsive disorder, phobic disorder); neurodegenerative diseases (e.g., multiple sclerosis, Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), Parkinson’s disease, Huntington’s Disease, Guillain-Barre syndrome, myasthenia gravis, and chronic idiopathic demyelinating disease (CID)), movement disorders (e.g., dyskinesia, tremor, dystonia, chorea and ballism, tic syndromes, Tourette’s Syndrome, myoclonus, drug-induced movement disorders, Wilson’s Disease, Paroxysmal Dyskinesias, Stiff Man Syndrome and Akinetic-Rigid Syndromes and Parkinsonism), epilepsy, tinnitus, pain, phantom pain, diabetes neuropathy, enhancing or diminishing any neurological or psychiatric function not just an abnormality or disorder or others, as understood to skilled artisans and which are only omitted here for brevity. Neurological activity that may be modulated can include normal functions, such as alertness, conscious state, drive, fear, anger, anxiety, repetitive behavior, impulses, urges, obsessions, euphoria, sadness, and the fight or flight response, as well as instability, vertigo, dizziness, fatigue, photophobia, concentration dysfunction, memory disorders, headache, dizziness, irritability, fatigue, visual disturbances, sensitivity to noise (misophonia, hyperacusis, phonophobia), judgment problems, depression, symptoms of traumatic brain injury (whether physical, emotional, social, or chemical), autonomic functions, which includes sympathetic or parasympathetic functions (e.g., control of heart rate), somatic functions, or enteric functions.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat an inflammatory disorder, such as Alzheimer’s disease, Sjogren’s syndrome, ankylosing spondylitis, arthritis (osteoarthritis, rheumatoid arthritis (RA), psoriatic arthritis), asthma, atherosclerosis, Crohn’s disease, colitis, dermatitis, diverticulitis, fibromyalgia, hepatitis, irritable bowel syndrome (IBS), systemic lupus erythematous (SLE), nephritis, Parkinson’s disease, ulcerative colitis, chronic peptic ulcer, tuberculosis, periodontitis, sinusitis, hepatitis, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a gastrointestinal condition, such as ileus, irritable bowel syndrome, Crohn’s disease, ulcerative colitis, diverticulitis, gastroesophageal reflux disease, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a bronchial disorder, such as asthma, bronchitis, pneumonia, COPD, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a coronary artery disease, heart attack, arrhythmia, cardiomyopathy, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a urinary disorder, such as urinary incontinence, urinalysis, overactive bladder, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat addiction, alcoholism, alcohol dependence or opioid-use disorders. In some cases, the devices may be used as a bridge-therapy for alcohol dependence or opioid-use disorders to reduce opioid or alcohol cravings sufficiently to remain drug-free prior to receiving further treatment, such as prescription injection medications or other alcohol and drug recovery programs.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a cancer, such as bladder cancer, breast cancer, prostate cancer, lung cancer, colon or rectal cancer, skin cancer, thyroid cancer, brain cancer, leukemia, liver cancer, lymphoma, pancreatic cancer, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the devices described herein can be configured to prevent, diagnose, monitor, ameliorate, or treat a metabolic disorder, such as diabetes (type 1, type 2, or gestational), Gaucher’s disease, sick cell anemia, cystic fibrosis, hemochromatosis, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, the neurostimulator can modulate central or peripheral nervous systems. For example, the neurostimulator can be enable spinal cord stimulation to provide therapy for intractable pain and refractory angina; occipital nerve stimulation to provide therapy for occipital neuralgia and transformed migraine; afferent vagus nerve modulation to provide therapy for a host of neurological and neuropsychiatric disorders, such as epilepsy, depression, Parkinson’s disease, bulemia, anxiety/obsessive compulsive disorders, Alzheimer’s disease, autism, and neurogenic pain; efferent vagus nerve stimulation for rate control in atrial fibrillation, and to provide therapy for congestive heart failure; gastric nerves or gastric wall stimulation to provide therapy for obesity; sacral nerve stimulation to provide therapy for urinary urge incontinence; deep brain stimulation to provide therapy for Parkinson’s disease, and other neurological and neuropsychiatric disorders; cavernous nerve stimulation to provide therapy for erectile dysfunction .
In other embodiments, the stimulator can be enable spinal cord stimulation to provide therapy for intractable pain and refractory angina; occipital nerve stimulation to provide therapy for occipital neuralgia and transformed migraine; afferent vagus nerve modulation to provide therapy for a host of neurological and neuropsychiatric disorders, such as epilepsy, depression, Parkinson’s disease, bulemia, anxiety/obsessive compulsive disorders, Alzheimer’s disease, autism, and neurogenic pain; efferent vagus nerve stimulation for rate control in atrial fibrillation, and to provide therapy for congestive heart failure; gastric nerves or gastric wall stimulation to provide therapy for obesity; sacral nerve stimulation to provide therapy for urinary urge incontinence; deep brain stimulation to provide therapy for Parkinson’s disease, and other neurological and neuropsychiatric disorders; cavernous nerve stimulation to provide therapy for erectile dysfunction.
In other embodiments, the stimulator can be used to provide therapy to patient’s suffering from post-operative symptoms following major surgery and/or for treating patients in critical or intensive care. Post-operative symptoms may include nausea, vomiting, constipation, gas, post-operative ileus, post-operative pain, restlessness, sleeplessness and the like. In some embodiments, the systems and methods are particularly useful for mitigating or eliminating the impairment of gastrointestinal (GI) motility after intra-abdominal or nonabdominal surgery, such as post-operative ileus (POI). In some embodiments, the systems and methods may reduce opioid-induced and/or inflammatory-induced dysfunction of intestinal transit to improve motility, thereby allowing faster release of patient’s from the hospital.
For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a neurological condition, such as epilepsy, headache/migraine, whether primary or secondary, whether cluster or tension, neuralgia, sub-arachnoid hemorrhage, post-traumatic headache, traumatic brain injury (TBI), seizures, vertigo, dizziness, concussion, aneurysm, palsy, Parkinson’s disease, Alzheimer’s disease, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat an inflammatory disease or disorder, such as Alzheimer’s disease, ankylosing spondylitis, arthritis (osteoarthritis, rheumatoid arthritis (RA), Sjôgren’s syndrome, temporal arteritis, Type 2 diabetes, psoriatic arthritis, asthma, atherosclerosis, Crohn’s disease, colitis, dermatitis, diverticulitis, fibromyalgia, hepatitis, irritable bowel syndrome (IBS), systemic lupus erythematous (SLE), nephritis, fibromyalgia, Celiac disease, Parkinson’s disease, ulcerative colitis, chronic peptic ulcer, tuberculosis, periodontitis, sinusitis, hepatitis, Grave’s disease, psoriasis, pernicious anemia (PA), peripheral neuropathy, lupus or others, as understood to skilled artisans and which are only omitted here for brevity. For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a gastrointestinal condition, such as ileus, irritable bowel syndrome, Crohn’s disease, ulcerative colitis, diverticulitis, gastroesophageal reflux disease, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a bronchial disorder, such as asthma, bronchitis, pneumonia, or others, as understood to skilled artisans and which are only omitted here for brevity. For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a coronary artery disease, heart attack, arrhythmia, cardiomyopathy, or others, as understood to skilled artisans and which are only omitted here for brevity. For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a urinary disorder, such as urinary incontinence, urinalysis, overactive bladder, or others, as understood to skilled artisans and which are only omitted here for brevity.
For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat eat a cancer, such as bladder cancer, breast cancer, prostate cancer, lung cancer, colon or rectal cancer, skin cancer, thyroid cancer, brain cancer, leukemia, liver cancer, lymphoma, pancreatic cancer, or others, as understood to skilled artisans and which are only omitted here for brevity. For example, some systems and methods can be configured to prevent, diagnose, monitor, ameliorate, or treat a metabolic disorder, such as diabetes (type 1, type 2, or gestational), Gaucher’s disease, sick cell anemia, cystic fibrosis, hemochromatosis, or others, as understood to skilled artisans and which are only omitted here for brevity.
As a preliminary matter, we first describe the vagus nerve itself and its most proximal connections. A fact that electrical stimulation of a vagus nerve can be used to treat many disorders may be understood as follows. The vagus nerve is composed of motor and sensory fibers. The vagus nerve leaves the cranium, passes down the neck within the carotid sheath to the root of the neck, then passes to the chest and abdomen, where it contributes to the innervation of the viscera. A human vagus nerve (tenth cranial nerve, paired left and right) comprises of over 100,000 nerve fibers (axons), mostly organized into groups. The groups are contained within fascicles of varying sizes, which branch and converge along the nerve. Under normal physiological conditions, each fiber conducts electrical impulses only in one direction, which is defined to be the orthodromic direction, and which is opposite the antidromic direction. However, external electrical stimulation of the nerve may produce action potentials that propagate in orthodromic and antidromic directions. Besides efferent output fibers that convey signals to the various organs in the body from the central nervous system, the vagus nerve conveys sensory (afferent) information about the state of the body’s organs back to the central nervous system. Some 80-90% of the nerve fibers in the vagus nerve are afferent (sensory) nerves, communicating the state of the viscera to the central nervous system.
The largest nerve fibers within a left or right vagus nerve are approximately 20 µm in diameter and are heavily myelinated, whereas only the smallest nerve fibers of less than about 1 µm in diameter are completely unmyelinated. When the distal part of a nerve is electrically stimulated, a compound action potential may be recorded by an electrode located more proximally. A compound action potential contains several peaks or waves of activity that represent the summated response of multiple fibers having similar conduction velocities. The waves in a compound action potential represent different types of nerve fibers that are classified into corresponding functional categories, with approximate diameters as follows: A-alpha fibers (afferent or efferent fibers, 12-20 µm diameter), A-beta fibers (afferent or efferent fibers, 5-12 µm), A-gamma fibers (efferent fibers, 3-7 µm), A-delta fibers (afferent fibers, 2-5 µm), B fibers (1-3 µm) and C fibers (unmyelinated, 0.4-1.2 µm). The diameters of group A and group B fibers include the thickness of the myelin sheaths.
The vagus (or vagal) afferent nerve fibers arise from cell bodies located in the vagal sensory ganglia, which take the form of swellings near the base of the skull. Vagal afferents traverse the brainstem in the solitary tract, with some eighty percent of the terminating synapses being located in the nucleus of the tractus solitarius (or nucleus tractus solitarii, nucleus tractus solitarius, or NTS). The NTS projects to a wide variety of structures in the central nervous system, such as the amygdala, raphe nuclei, periaqueductal gray, nucleus paragigantocellurlais, olfactory tubercule, locus ceruleus, nucleus ambiguous and the hypothalamus. The NTS also projects to the parabrachial nucleus, which in turn projects to the hypothalamus, the thalamus, the amygdala, the anterior insula, and infralimbic cortex, lateral prefrontal cortex, and other cortical regions [JEAN A. The nucleus tractus solitarius: neuroanatomic, neurochemical and functional aspects. Arch Int Physiol Biochim Biophys 99(5,1991):A3-A52 the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein]. Thus, stimulation of vagal afferents can modulate the activity of many structures of the brain and brainstem through these projections.
With regard to vagal efferent nerve fibers, two vagal components have evolved in the brainstem to regulate peripheral parasympathetic functions. The dorsal vagal complex, consisting of the dorsal motor nucleus and its connections controls parasympathetic function primarily below the level of the diaphragm, while the ventral vagal complex, comprised of nucleus ambiguous and nucleus retrofacial, controls functions primarily above the diaphragm in organs such as the heart, thymus and lungs, as well as other glands and tissues of the neck and upper chest, and specialized muscles such as those of the esophageal complex. For example, the cell bodies for the preganglionic parasympathetic vagal neurons that innervate the heart reside in the nucleus ambiguus, which is relevant to potential cardiovascular side effects that may be produced by vagus nerve stimulation.
The vagus efferent fibers innervate parasympathetic ganglionic neurons that are located in or adjacent to each target organ. The vagal parasympathetic tone resulting from the activity of these fibers is balanced reflexively in part by sympathetic innervations. Consequently, electrical stimulation of a vagus nerve may result not only in modulation of parasympathetic activity in postganglionic nerve fibers, but also a reflex modulation of sympathetic activity. The ability of a vagus nerve to bring about widespread changes in autonomic activity, either directly through modulation of vagal efferent nerves, or indirectly via activation of brainstem and brain functions that are brought about by electrical stimulation of vagal afferent nerves, accounts for the fact that vagus nerve stimulation can treat many different medical conditions in many end organs. Selective treatment of particular conditions is possible because the parameters of the electrical stimulation (e.g. frequency, amplitude, pulse width, etc.) may selectively activate or modulate the activity of particular afferent or efferent A, B, and/or C fibers that result in a particular physiological response in each individual.
Depending on the medical indication, whether it is a chronic or acute treatment, and the natural history of the disease, different treatment protocols may be used. In particular, applicant has discovered that it is not necessary to “continuously stimulate” the vagus nerve (or to in order to provide clinically efficacious benefits to patients with certain disorders. The term “continuously stimulate” as defined herein means stimulation that follows a certain On/Off pattern continuously 24 hours/day. For example, existing implantable vagal nerve stimulators “continuously stimulate” the vagus nerve with a pattern of 30 seconds ON/ 5 minutes OFF (or the like) for 24 hours/day and seven days/week. Applicant has determined that this continuous stimulation is not necessary to provide the desired clinical benefit for many disorders.
The present description contemplates three types of interventions involving stimulation of a vagus nerve: prophylactic, acute and compensatory (rehabilitative). Among these, the acute treatment involves the fewest administrations of vagus nerve stimulations, which begin upon the appearance of symptoms. It is intended primarily to enlist and engage the autonomic nervous system to inhibit excitatory neurotransmissions that accompany the symptoms. The prophylactic treatment resembles the acute treatment in the sense that it is administered as though acute symptoms had just occurred (even though they have not) and is repeated at regular intervals, as though the symptoms were reoccurring (even though they are not). The rehabilitative or compensatory treatments, on the other hand, seek to promote long-term adjustments in the central nervous system, compensating for deficiencies that arose as the result of the patient’s disease by making new neural circuits.
A vagus nerve stimulation treatment is conducted for continuous period of thirty seconds to five minutes, preferably about 90 seconds to about three minutes and more preferably about two minutes (each defined as a single dose). After a dose has been completed, the therapy is stopped for a period of time (depending on the treatment as described below). For prophylactic treatments, such as a treatment to reduce cortisol or other stress hormone levels, the therapy preferably comprises multiple doses/day over a period of time that may last from one day to a number of months or even years. In certain embodiments, the treatment will comprise multiple doses at predetermined times during the day and/or at predetermined intervals throughout the day. In exemplary embodiments, the treatment comprises one of the following: (1) 3 doses/day at predetermined intervals or times; (2) two doses, either consecutively, or separated by 5 min at predetermined intervals or times, preferably two or three times/day; (3) 3 doses, either consecutively or separated by 5 min again at predetermined intervals or times, such as 2 or 3 times/day; or (4) 1-3 doses, either consecutively or separated by 5 min, 4-6 times per day.
In exemplary embodiments, the treatment comprises one of the following: (1) 2-12 doses/day, preferably about 2-4 doses, at predetermined intervals or times; (2) two doses, either consecutively, or separated by 5 min at predetermined intervals or times, preferably two to four times/day; (3) 3 doses, either consecutively or separated by 5 min again at predetermined intervals or times, such as 2 or 3 times/day; or (4) 1-3 doses, either consecutively or separated by 5 min, 4-6 times per day.
For certain disorders, the time of day can be more important than the time interval between treatments. For example, the locus correleus has periods of time during a 24 hour day wherein it has inactive periods and active periods. Typically, the inactive periods can occur in the late afternoon or in the middle of the night when the patient is asleep. It is during the inactive periods that the levels of inhibitory neurotransmitters in the brain that are generated by the locus correleus are reduced. This may have an impact on certain disorders. For example, patients suffering from migraines or cluster headaches often receive these headaches after an inactive period of the locus correleus. For these types of disorders, the prophylactic treatment is optimal during the inactive periods such that the amounts of inhibitory neurotransmitters in the brain can remain at a higher enough level to mitigate or abort an acute attack of the disorder.
In these embodiments, the prophylactic treatment may comprise multiple doses/day timed for periods of inactivity of the locus correleus. In one embodiment, a treatment comprises one or more doses administered 2-3 times per day or 2-3 “treatment sessions” per day. The treatment sessions preferably occur during the late afternoon or late evening, in the middle of the night and again in the morning when the patient wakes up. In an exemplary embodiment, each treatment session comprises 1-4 doses, preferably 2-3 doses, with each dose lasting for about 60 seconds to about 5 minutes, preferably about 90 seconds to about three minutes.
For other disorders, the intervals between treatment sessions may be the most important as applicant has determined that stimulation of the vagus nerve can have a prolonged effect on the inhibitor neurotransmitters levels in the brain, e.g., at least one hour, up to 3 hours and sometimes up to 8 hours. In one embodiment, a treatment comprises one or more doses (i.e., treatment sessions) administered at intervals during a 24 hour period. In a preferred embodiment, there are 1-5 such treatment sessions, preferably 2-4 treatment sessions. Each treatment session preferably comprises 1-3 doses, each “dose” lasting between about 60 seconds to about five minutes, preferably about 90 seconds to about 150 seconds, more preferably about 2 minutes.
For all of the treatments listed above, one may alternate treatment between left and right sides, or in the case of stroke or migraine that occur in particular brain hemispheres, one may treat ipsilateral or contralateral to the stroke-hemisphere or headache side, respectively. Or for a single treatment, one may treat one minute on one side followed by one minute on the opposite side. Variations of these treatment paradigms may be chosen on a patient-by-patient basis. However, it is understood that parameters of the stimulation protocol may be varied in response to heterogeneity in the symptoms of patients. Different stimulation parameters may also be selected as the course of the patient’s condition changes. In preferred embodiments, the disclosed methods and devices do not produce clinically significant side effects, such as agitation or anxiety, or changes in heart rate or blood pressure.
The prophylactic treatments may be most effective when the patient is in a prodromal, high-risk bistable state. In that state, the patient is simultaneously able to remain normal or exhibit symptoms, and the selection between normal and symptomatic states depends on the amplification of fluctuations by physiological feedback networks. For example, a thrombus may exist in either a gel or fluid phase, with the feedback amplification of fluctuations driving the change of phase and/or the volume of the gel phase. Thus, a thrombus may form or not, depending on the nonlinear dynamics exhibited by the network of enzymes involved in clot formation, as influenced by blood flow and inflammation that may be modulated by vagus nerve stimulation [PANTELEEV MA, Balandina AN, Lipets EN, Ovanesov MV, Ataullakhanov FI. Task-oriented modular decomposition of biological networks: trigger mechanism in blood coagulation. Biophys J 98(9,2010):1751-1761; Alexey M SHIBEKO, Ekaterina S Lobanova, Mikhail A Panteleev and Fazoil I Ataullakhanov. Blood flow controls coagulation onset via the positive feedback of factor VII activation by factor Xa. BMC Syst Biol 2010; 4(2010):5, pp. 1-12]. Consequently, the mechanisms of vagus nerve stimulation treatment during prophylaxis are generally different than what occurs during an acute treatment, when the stimulation inhibits excitatory neurotransmission that follows the onset of ischemia that is already caused by the thrombus. Nevertheless, the prophylactic treatment may also inhibit excitatory neurotransmission so as to limit the excitation that would eventually occur upon formation of a thrombus, and the acute treatment may prevent the formation of another thrombus.
Referring now to
In some embodiments, the same impulse generator 110, energy source 120, and control unit 130 may be used for either a magnetic stimulator or an electrode-based stimulator, allowing the user to change parameter settings depending on whether magnetic coils or the electrodes 140 are attached.
Although a pair of electrodes 140 is shown in
Electrodes 140 may include a suitable adhesive that secured them to a skin surface. Suitable adhesive electrodes for use herein may include electrode pads, self-adhesive electrodes or the like. In this embodiment, electrodes 140 may be placed in a suitable location on the patient’s neck and adhered thereto. Electrodes 140 receive electrical impulses from pulse generator 110. The duration, amplitude, frequency and treatment paradigm for the electrical impulses may be controlled by controller 130, a mobile device, or via another electronic device coupled to pulse generator 110. This embodiment allows, for example, a physician to secure electrodes 140 to the patient’s neck such that the treatment paradigm may be followed without patient involvement. This is particularly useful for treating patients that are unable or unwilling to self-treat. For example, in some cases, patients recovering from surgery, such as major colorectal surgery may be either incapable of self-treatment, or their compliance with the treatment protocol may not be complete. In another example, older patients may not have suitable mental faculties for self-treatment.
Stimulator 100 may be housed in an outer covering or patch 800 to protect stimulator from the environment (see
The stimulator in this embodiment includes one or more electrodes. The stimulator may also include a power source such as a battery, and a signal generator for applying the electrical impulses to the electrodes. Alternatively, the power source and/or the signal generator may be wirelessly coupled to the electrodes, as discussed above. An external controller may be wirelessly coupled to the stimulator to provide a stimulation protocol to the signal generator and to control other key functions of the signal, such as power, amplitude, duration frequency and the like.
The stimulator may reside in a housing that is removably coupled to the patch via a snap-fitting, Velcro, or other suitable attachment means. In this embodiment, the patch may be adhered to the patient and the stimulator may be removed and reattached without removing the patch. This allows the healthcare professions to, for example, recharge the battery, troubleshoot the device and/or control the stimulation therapy on the device.
The stimulator may also include a conductive fluid, such as a gel pad, disposed between the electrode(s) and the patient’s outer skin surface to enhance conductivity of the electrical impulses through the outer skin surface to the nerve.
Alternatively, the outer covering may comprise any wearable material that may include the stimulator. For example, depending on the location of the target nerve on the patient’s body, the stimulator may be attached to, or embedded within, a wearable garment, such as a shirt, scarf, watch, hat, gloves, pants, shoes, boots, socks, underwear, belt, dress, jacket, sweater, ear muffs, or the like. The wearable garment may also comprise an accessory, such as a wristband, ankle or wrist bracelet, necklace, earrings, a compression garment, an ankle or knee brace or the like.
In yet another embodiment, the garment itself is the stimulator. For example, the garment may comprise an electronic textile or e-textile that includes fabrics that enable digital components, such as electrodes, pulse generators, batteries wireless receivers and other electronic components to be embedded therein. Electronic textiles are distinct from wearable garments because the emphasis is placed on the seamless integration of textiles with electronic elements like microcontrollers, sensors, and actuators. In one embodiment, the electronic textile may comprise an organic electronics material that is conducting and has insulated electrical components that allows the garment to be washed without damaging the electronic components.
The stimulator may also include an array of electrodes. The electrode array may include multiple sets of electrodes with each set of electrodes configured to apply electrical impulses through the outer skin surface of the patient, as discussed above. Each of the sets of electrodes may be individually coupled to the pulse generator, either directly, through wires, or wireless as described above. The electrode array may have multiple patterns. For example, the array may be linear, square, circular or any other suitable shape.
In certain embodiments, the electrode array comprises two or more sets of electrodes, each spaced apart from each other between about 2 mm to about 25 mm, preferably between about 4 mm to about 10 mm. The electrode array preferably comprises a shape that substantially corresponds to a target area of the patient’s neck. In one embodiment, the target area is the area on the neck that allows for electrical impulses to be passed through the skin to the vagus nerve (discussed in detail below).
The electrode sets may each be individually coupled to the pulse generator and/or the controller such that electrical impulses can be applied to all of the electrode sets, some of the electrode sets or only one of the electrode sets. In certain embodiments, the controller is configured to apply electrode impulses to only those electrodes positioned optimally for stimulating the nerve. In addition, the selection of electrodes may be dynamic and change over time.
In one such embodiment, the electrodes are arranged in an array or matrix that may contain tens to hundreds of microelectrodes. The microelectrodes may each be independently coupled to the pulse generator 110 such that the pulse generator can apply current to any one or a plurality of the microelectrodes. In some embodiments, groups of the microelectrodes are coupled together and then coupled to the pulse generator 110 such that electric current can be applied independently to each group. In an exemplary embodiment, the electrodes have a size of about 0.5 to 2.0 mm, preferably about 1.0 mm, and are spaced from each other a distance of about 0.5 to about 10 mm, preferably between about 2.0 mm and 5.0 mm (e.g., 3.0 mm).
Electrode array 900 may be included on the housing of a stimulator device, such as those described below. Alternatively, array 900 may be included as part of a patch, such as the patch 800 shown in
Stimulator 100 further comprises one or more sensors 170 coupled to stimulator 100 and/or electrodes 140 (or the microelectrodes in the array) for detecting whether the nerve has been stimulated, the amplitude of the stimulation, or whether the nerve has been stimulated with sufficient amplitude and other parameters to fire an action potential. The sensors 170 may detect a physiological parameter of the patient. Physiological parameters may include, for example, blood flow associated with a nerve, such as vagal artery or cerebral blood flow, heart rate or variability, ECG, respiration depth and rate, core temperature, hydration, blood pressure, brain function, oxygenation, skin impedance, and skin temperature, pupil diameter (e.g., pupil dilation), galvanic skin response, selected biomarkers or other chemicals, a property of a voice of the patient, a laryngeal electromyographic signal, an electroglottographic signal, a property of the autonomic nervous system and the like. Alternatively, the sensors 170 may be coupled to the electrodes 140 and may sense one or more parameters of the electrodes, such as impedance, amplitude, voltage or the like.
The sensors 170 may also be coupled to the controller 130. In this embodiment, the controller 130 is configured to receive input from the sensors and to direct the pulse generator 110 to apply electrical impulses to one or more sets of the electrodes 140 based on this input. For example, the sensors 170 may provide data that suggests that one or more of the sets of electrodes is not positioned properly to stimulate the nerve, or to stimulate the nerve at the optimal signal strength to cause the nerve to fire an action potential. The controller 130 is configured to shift the electrical impulse to the set or sets of electrodes that provide a sufficient electrical impulse to the nerve to cause it to fire an action potential. In this manner, the controller 130 can optimize the application of the electrical impulses to the nerve.
Sensor(s) 170 may be coupled to electrodes 140, or they may be formed as part of the electrodes 140. Alternatively, sensor(s) 140 may be only coupled to stimulator 100, or they may be coupled to a separate device, such as a mobile device (discussed below). In certain embodiments, stimulator 100 will comprise a housing that includes both electrodes 140 and sensors 170, as discussed in more detail below.
In certain embodiments, sensor(s) 170 are configured to detect a target position for stimulating a selected nerve within a patient. The target position may, for example, be located on an outer skin surface of the patient and the selected nerve may be located within the patient under the skin surface. In some cases, the selected nerve may be located deep within the patient, i.e., greater than 5 mm below the outer skin surface, greater than 10 mm, or even greater than 20 mm below. In one such embodiment, the selected nerve is the vagus nerve and the target location is a position on the outer skin surface of the neck of the patient suitable for passing an electrical impulse through the skin sufficient to modulate the vagus nerve.
In one embodiment, sensor 170 comprises a heart pulse sensor configured to detect a heart pulse in the patient. The heart pulse sensor may be any suitable sensor known in the art for detecting the heart pulse of a patient, such as an infrared sensor, optical sensor, tactile sensor, a photoplethysmography (PPG) sensor or the like. The heart pulse sensor may, for example, detect the change in volume of a blood vessel that occurs when the heart pumps blood. Alternatively, the heart pulse sensor may detect vibrations, sounds or other indications that the sensor 170 is located adjacent to, or near, the patient’s heart pulse.
The heart pulse sensor is preferably designed to contact the patient’s outer skin surface and detect a pulse adjacent to, or near the sensor. However, in certain embodiments, the heart pulse sensor may be designed to detect the heart pulse without contacting the skin surface, e.g., through vibration, sound or other detection mechanisms. In these embodiments, sensor 170 may, for example, be located within stimulator 100, or within a separate device.
Sensors 170 may be coupled to an indicator 160 within stimulator 100, or within a separate device, such as a mobile device (discussed in more detail below). Indicator 160 is configured to generate an alert when sensors 170 have detected the target nerve. The alert may be, for example, a visual, tactile or audial alert, that provides the user with an indication that the sensor 170 has detected the target location.
In one such embodiment, sensor 170 comprises a heart pulse sensor that is configured to detect a heart pulse emanating from the carotid artery in the patient’s neck. The vagus nerve is situated within the carotid sheath, near the carotid artery and the interior jugular vein. The carotid sheath is located at the lateral boundary of the retropharyngeal space on each side of the neck and deep to the sternocleidomastoid muscle.
As discussed in detail below in reference to
Sensors 170 are configured to detect the heart pulse emanating from the carotid artery to provide an indication that electrodes 150 are located adjacent to, or near the carotid sheath and/or the external jugular vein and thus near the vagus nerve. This provides confirmation to the user that the device is positioned optimally for stimulating the vagus nerve.
In certain embodiments, sensors 170 may be configured to detect a magnitude of the heart pulse emanating from the carotid artery. In these embodiments, the sensors 170 may be configured, for example, to only provide an indication that the heart pulse has been detected when the magnitude of heart pulse reaches a threshold level, indicating that the sensor is close to the carotid artery. Alternatively, the sensors 170 may transmit the magnitude of heart pulse detected to a controller or suitable electronics within stimulator, or a separate mobile device.
In certain embodiments, indicator 160 is configured to transmit an alert that is associated with the magnitude of the heart pulse. For example, the alert may comprise an audible sound that increases in decibel level as the magnitude increase. In another example, the alert may comprise a vibration that increases in intensity or frequency as the magnitude of the heart pulse increases. In yet another example, the alert may comprise a visual signal, such as a blinking light that increases in intensity with heart pulse magnitude, different colored lights associated with threshold magnitudes of heart pulse, or another visual signal, such as bars, lines or other shapes that increase in size (e.g., length or width) with increasing heart pulse magnitude.
The indicator 160 may further be configured to provide a second alert when the magnitude of the heart pulse reaches a threshold level associated with optimal positioning of the sensor 170 and/or the electrodes 150. For example, if the indicator is providing a blinking light that increases in intensity with heart pulse magnitude, the second alert may be that the blinking light stops blinking and becomes constant, or it changes color (e.g., from yellow to green), or a separate alert is produced, such as a sound, vibration or the like.
In this embodiment, the sensor 160 may comprise a heart pulse sensor configured to contact the outer skin surface of the patient and directly detect the pulse within the carotid sheath, such as an infrared sensor, optical sensor, tactile sensor, a photoplethysmography (PPG) sensor or the like.
Alternatively, the sensor 160 may comprise an ultrasound transducer or probe configured to detect the location of the vagus nerve underlying 100 stimulator. The probe may be housed within stimulator 100, or it may be a separate device. The probe may be connected to an ultrasound machine that displays the anatomical structures that lie under the probe. Alternatively, the probe may be coupled to a controller or other device that is configured to provide an indication or alert when the probe has illustrated the carotid sheath.
The control unit 130 controls the impulse generator 110 to generate a signal for each of the device’s electrodes (or magnetic coils). The signals are selected to be suitable for amelioration of a particular medical condition when the signals are applied non-invasively to a target nerve or tissue via the electrodes 140. It is noted that nerve stimulating/modulating device 100 may be referred to by its function as a pulse generator. Patent application publications US2005/0075701 and US2005/0075702, both to SHAFER, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein, contain descriptions of pulse generators that may be applicable to this disclosure. By way of example, a pulse generator is also commercially available, such as Agilent 33522A Function/Arbitrary Waveform Generator, Agilent Technologies, Inc., 5301 Stevens Creek Blvd Santa Clara CA 95051.
The control unit 130 may comprise a general purpose computer, comprising one or more CPU, computer memories for the storage of executable computer programs (including the system’s operating system) and the storage and retrieval of data, disk storage devices, communication devices (such as serial and USB ports) for accepting external signals from a keyboard, computer mouse, and touchscreen, as well as any externally supplied physiological signals, analog-to-digital converters for digitizing externally supplied analog signals, communication devices for the transmission and receipt of data to and from external devices such as printers and modems that comprise part of the system, hardware for generating the display of information on monitors or display screens that comprise part of the system, and busses to interconnect the above-mentioned components. Thus, the user may operate the system by typing or otherwise providing instructions for the control unit 130 at a device such as a keyboard or touchscreen and view the results on a device such as the system’s computer monitor or display screen, or direct the results to a printer, modem, and/or storage disk. Control of the system may be based upon feedback measured from externally supplied physiological or environmental signals. Alternatively, the control unit 130 may have a compact and simple structure, for example, wherein the user may operate the system using only an on/off switch and energy control wheel or knob, or their touchscreen equivalent. In a section below, an embodiment is also described wherein the stimulator housing has a simple structure, but other components of the control unit 130 are distributed into other devices.
Parameters for the nerve or tissue stimulation include energy level, frequency and train duration (or pulse number). The stimulation characteristics of each pulse, such as depth of penetration, strength and selectivity, depend on the rise time and peak electrical energy transferred to the electrodes, as well as the spatial distribution of the electric field that is produced by the electrodes. The rise time and peak energy are governed by the electrical characteristics of the stimulator and electrodes, as well as by the anatomy of the region of current flow within the patient. In some embodiments, pulse parameters are set in such a way as to account for the detailed anatomy surrounding the nerve that is being stimulated [Bartosz SAWICKI, Robert Szmurło, Przemystaw Płonecki, Jacek Starzyński, Stanisław Wincenciak, Andrzej Rysz. Mathematical Modelling of Vagus Nerve Stimulation. pp. 92-97 in: Krawczyk, A. Electromagnetic Field, Health and Environment: Proceedings of EHE′07. Amsterdam, IOS Press, 2008, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein]. Pulses may be monophasic, biphasic or polyphasic. In some embodiments, some devices include those that are fixed frequency, where each pulse in a train has the same inter-stimulus interval, and those that have modulated frequency, where the intervals between each pulse in a train can be varied.
In addition, or as an alternative to some of the devices to implement the modulation unit for producing the electrical voltage/current profile of the stimulating, blocking and/or modulating impulse to the electrodes, the device disclosed in US Patent Application Publication No. US2005/0216062, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein, may be employed. That patent publication discloses a multifunctional electrical stimulation (ES) system adapted to yield output signals for effecting electromagnetic or other forms of electrical stimulation for a broad spectrum of different biological and biomedical applications, which produce an electric field pulse in order to non-invasively stimulate nerves. The system includes an ES signal stage having a selector coupled to a plurality of different signal generators, each producing a signal having a distinct shape, such as a sine wave, a square or a saw-tooth wave, or simple or complex pulse, the parameters of which are adjustable in regard to amplitude, duration, repetition rate and other variables. Examples of the signals that may be generated by such a system are described in a publication by LIBOFF [A.R. LIBOFF. Signal shapes in electromagnetic therapies: a primer. pp. 17-37 in: Bioelectromagnetic Medicine (Paul J. Rosch and Marko S. Markov, eds.). New York: Marcel Dekker (2004), the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein]. The signal from the selected generator in the ES stage is fed to at least one output stage where it is processed to produce a high or low voltage or current output of a desired polarity whereby the output stage is capable of yielding an electrical stimulation signal appropriate for its intended application. Also included in the system is a measuring stage which measures and displays the electrical stimulation signal operating on the substance being treated, as well as the outputs of various sensors which sense prevailing conditions prevailing in this substance, whereby the user of the system can manually adjust the signal, or have it automatically adjusted by feedback, to provide an electrical stimulation signal of whatever type the user wishes, who can then observe the effect of this signal on a substance being treated.
The stimulating and/or modulating impulse signal 160 preferably has a frequency, an amplitude, a duty cycle, a pulse width, a pulse shape, etc. selected to influence the therapeutic result, namely, stimulating and/or modulating some or all of the transmission of the selected nerve. For example, the frequency may be about 1 Hz or greater, such as between about 15 Hz to 100 Hz, preferably between about 15-50 Hz and more preferably between about 15-35 Hz. In some embodiments, the frequency is 25 Hz. The modulation signal may have a pulse width selected to influence the therapeutic result, such as about 1 microseconds to about 1000 microseconds, preferably about 100-400 microseconds and more preferably about 200-400 microseconds. For example, the electric field induced or produced by the device within tissue in the vicinity of a nerve may be about 5 to 600 V/m, preferably less than 100 V/m, and even more preferably less than 30 V/m. The gradient of the electric field may be greater than 2 V/m/mm. More generally, the stimulation device produces an electric field in the vicinity of the nerve that is sufficient to cause the nerve to depolarize and reach a threshold for action potential propagation, which is approximately 8 V/m at 1000 Hz. The modulation signal may have a peak voltage amplitude selected to influence the therapeutic result, such as about 0.2 volts or greater, such as about 0.2 volts to about 40 volts, preferably between about 1-20 volts and more preferably between about 2-12 volts.
In an exemplary embodiment, the waveform comprises bursts of sinusoidal pulses, as shown in
The above waveform is essentially a 1-20 kHz signal that includes bursts of pulses with each burst having a frequency of about 5-100 Hz and each pulse having a frequency of about 1-20 kHz. Another way of thinking about the waveform is that it is a 1-20 kHz waveform that repeats itself at a frequency of about 5-100 Hz.
Invasive nerve stimulation typically uses square wave pulse signals. However, Applicant found that square waveforms are not ideal for non-invasive stimulation, as they produce excessive pain, but still can be used. Prepulses and similar waveform modifications have been suggested as methods to improve selectivity of nerve stimulation waveforms, but Applicant also did not find them ideal, although they still can be used [Aleksandra VUCKOVIC, Marco Tosato and Johannes J Struijk. A comparative study of three techniques for diameter selective fiber activation in the vagal nerve: anodal block, depolarizing prepulses and slowly rising pulses. J. Neural Eng. 5 (2008): 275-286, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein; Aleksandra VUCKOVIC, Nico J. M. Rijkhoff, and Johannes J. Struijk. Different Pulse Shapes to Obtain Small Fiber Selective Activation by Anodal Blocking-A Simulation Study. IEEE Transactions on Biomedical Engineering 51(5,2004):698-706, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein; Kristian HENNINGS. Selective Electrical Stimulation of Peripheral Nerve Fibers: Accommodation Based Methods. Ph.D. Thesis, Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark, 2004, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein].
In some embodiments, the use of feedback to generate the modulation signal 160 may result in a signal that is not periodic, particularly if the feedback is produced from sensors that measure naturally occurring, time-varying aperiodic physiological signals from the patient. In fact, the absence of significant fluctuation in naturally occurring physiological signals from a patient is ordinarily considered to be an indication that the patient is in ill health. This is because a pathological control system that regulates the patient’s physiological variables may have become trapped around only one of two or more possible steady states and is therefore unable to respond normally to external and internal stresses. Accordingly, even if feedback is not used to generate the modulation signal 160, it may be useful to artificially modulate the signal in an aperiodic fashion, in such a way as to simulate fluctuations that would occur naturally in a healthy individual. Thus, the noisy modulation of the stimulation signal may cause a pathological physiological control system to be reset or undergo a non-linear phase transition, through a mechanism known as stochastic resonance [B. SUKI, A. Alencar, M.K. Sujeer, K.R. Lutchen, J.J. Collins, J.S. Andrade, E.P. Ingenito, S. Zapperi, H.E. Stanley, Life-support system benefits from noise, Nature 393 (1998) 127-128, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein; W Alan C MUTCH, M Ruth Graham, Linda G Girling and John F Brewster. Fractal ventilation enhances respiratory sinus arrhythmia. Respiratory Research 2005, 6:41, pp. 1-9, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein].
In some embodiments, the modulation signal 160, with or without feedback, will stimulate the selected nerve fibers in such a way that one or more of the stimulation parameters (e.g., energy, frequency, and others mentioned herein) are varied by sampling a statistical distribution having a mean corresponding to a selected, or to a most recent running-averaged value of the parameter, and then setting the value of the parameter to the randomly sampled value. The sampled statistical distributions will comprise Gaussian and 1/f, obtained from recorded naturally occurring random time series or by calculated formula. Parameter values will be so changed periodically, or at time intervals that are themselves selected randomly by sampling another statistical distribution, having a selected mean and coefficient of variation, where the sampled distributions comprise Gaussian and exponential, obtained from recorded naturally occurring random time series or by calculated formula.
In some embodiments, some devices, as disclosed herein, are provided in a “pacemaker” type form, in which electrical impulses 162 are generated to a selected region of the nerve by a stimulator device on an intermittent basis, to create in the patient a lower reactivity of the nerve .
The electrodes of the some of the devices, as disclosed herein, are applied to the surface of the neck, or to some other surface of the body, and are used to deliver electrical energy non-invasively to a nerve. Embodiments may differ with regard to the number of electrodes that are used, the distance between electrodes, and whether disk, ring or other shapes of electrodes are used. In some embodiments, one selects the electrode configuration for individual patients, in such a way as to optimally focus electric fields and currents onto the selected nerve, without generating excessive currents on the surface of the skin.
Referring now to
Housing 202 contains the electronic components, signal generator and energy source (not shown) that are used to generate the signals that drive electrical impulses through electrodes 204, 206. However, in other embodiments, the electronic components that generate the signals may be in a separate housing or device, such as a mobile device. Furthermore, other embodiments may contain a single electrode or more than two electrodes.
Housing 202 comprises upper and lower portions 212, 214 and a cover 210 disposed between upper and lower portions 212, 214 for protecting electrodes 204, 206 from the external environment. Cover 210 also ensures that electrodes 204, 206 will not contact a patient’s tissue when the device is not intended to be used (e.g., in the event that the device is accidently turned ON and electric current is passed through electrodes when not in use). In certain embodiments, cover 210 is rotatably coupled to housing 202 such that it can be moved between a first position, wherein the electrodes 204, 206 are exposed for stimulation, and a second position, wherein the electrodes are housed and protected within the cover 210. Cover 210 may comprise any suitable material, such as polyphenylene ether (PPE), plastic, or other polymers.
Lower portion 214 of housing 202 preferably includes curved side surfaces 216, 218 with substantially planar surfaces 220 therebetween to form an overall disc-like shape that is cut off on the upper and lower portions of the disc. Lower portion 214 also includes a substantially planar bottom surface 228 that includes a control panel 240 (discussed below).
Similarly, upper portion 212 of housing preferably comprises curved side surfaces 224 and a substantially planar upper surface 229. Electrodes 204, 206 extend outward from upper surface 229. Upper portion 212 has a smaller width and length as lower portion 214 to form a groove 236 therebetween. Cover 210 rotates within groove 236. Upper and lower portions 212, 214 are preferably coupled to each other within housing 202. Alternatively, they may be molded together and formed as an integral component.
Control panel 240 may include a number of user controls and/or device status indicators. In alternative embodiments, the controls and status indicators are located on a separate device, such as a mobile device, that is wirelessly (e.g. Bluetooth or the like) coupled to stimulator 200.
In a preferred embodiment, control panel 240 includes intensity controls 242 for controlling the level of intensity or amplitude of the electrical impulses generated by stimulation 200. Intensity controls 242 extend outward from lower surface 228 so that the user be tactically identify and control intensity controls 242.
Control panel 240 may further comprise a battery life indicator 244 and/or a dose duration indicator 246. These indicators may include, for example, LEDs or other light sources, to facilitate identification by the user. The dose duration indicator 246 provides an indication of the time remaining on a single dose of electrical stimulation. In certain embodiments, stimulation 200 is configured to automatically cease the generation of the electrical impulse when the duration of the single dose has been completed.
Stimulator 200 may further include a power control 250 for turning ON the device. Power control 250 may also include an LED or other light source for illuminating power control 250 when the device has been turned ON. In one embodiment, power control 250 is located on side surface 200, although it will be understood that power control 250 may be located on control panel 240 or elsewhere on stimulator 200.
In certain embodiments, stimulator 200 further includes a charging pad 260 coupled to a suitable connector for providing power to stimulator 200 and/or recharging the battery within stimulator 200. Charging pad 260 may comprise any suitable charging source, such as an inductive charging source that provides power via inductive transmission through the lower surface 228 of housing 202.
Stimulator 200 may further include a gel pad 270 that includes a conductive gel 272, 274 positioned to contact electrodes 204, 206 when gel pad 270 is positioned over upper surface 229. Gel pad 270 is configured to apply a coating of electrically conductive gel to the surfaces of electrodes 204, 206 to facilitate conduction of the electrical impulses through an outer skin surface of the patient.
The housing 202 may comprise plastic, metal, rubber, or other materials. The housing 202 may be rigid, elastic, resilient, or flexible. The housing 202 may be included in, or embodied as, a phone, a tablet, a laptop, a phone/tablet/laptop case, a patch, an adhesive bandage, a strip, an anklet, a belt, a bracelet, a necklace, a garment, a pad, a ring, a mattress, a pillow, a blanket, a robot, a surgical instrument, a stimulator, an infusion device, or others. The housing 202 may be embodied as described in US Patent Application Publication 20140330336 and US Patents 8874205, 9174066, 9205258, 9375571, and 9427581, all of which are incorporated entirely herein by reference for all purposes as if copied and pasted herein.
Electrodes 204, 206 may comprise a substantially solid conducting material (e.g., metal such as stainless steel, platinum, or a platinum-iridium alloy), which is possibly flexible in some embodiments. However, in other embodiments, the electrodes may have many other sizes and shapes, and they may be made of other materials. The electrodes preferably have a dome-shape with a rounded distal surface, although they may have the shape of a screw that is flattened on its tip. Pointing of the tip would make the electrode more of a point source, such that the equations for the electrical potential may have a solution corresponding more closely to a far-field approximation. Rounding of the electrode surface or making the surface with another shape will likewise affect the boundary conditions that determine the electric field.
In other embodiments, electrodes 204, 206 may be housed within housing 200. In these embodiments, housing includes an outer contact surface, such as a fluid permeable material that allows for passage of current through the permeable portions of the material. In these embodiments, a conductive medium (such as a gel) is preferably situated between the electrode(s) and the permeable interface. The conductive medium provides a conductive pathway for electrons to pass through the permeable interface to the outer surface of the interface and to the patient’s skin.
In other embodiments, the interface is made from a very thin material with a high dielectric constant, such as material used to make capacitors. For example, it may be Mylar having a submicron thickness (preferably in the range about 0.5 to about 1.5 microns) having a dielectric constant of about 3. Because one side of Mylar is slick, and the other side is microscopically rough, two different configurations are contemplated: one in which the slick side is oriented towards the patient’s skin, and the other in which the rough side is so-oriented. Thus, at stimulation Fourier frequencies of several kilohertz or greater, the dielectric interface will capacitively couple the signal through itself, because it will have an impedance comparable to that of the skin. Thus, the dielectric interface will isolate the stimulator’s electrode from the tissue, yet allow current to pass. In one embodiment, non-invasive electrical stimulation of a nerve is accomplished essentially substantially capacitively, which reduces the amount of ohmic stimulation, thereby reducing the sensation the patient feels on the tissue surface. This would correspond to a situation, for example, in which at least 30%, preferably at least 50%, of the energy stimulating the nerve comes from capacitive coupling through the stimulator interface, rather than from ohmic coupling. In other words, a substantial portion (e.g., 50%) of the voltage drop is across the dielectric interface, while the remaining portion is through the tissue.
In certain embodiments, stimulator 200 includes an electronic filter, such as a low-pass filter that filters out or eliminates high frequency components from the signal to smooth out the signal before it reaches the electrodes 204, 206. The low-pass filter may comprise a digital or analog filter or simply a capacitor placed in series between the signal generator and the electrode/interface. When the signal is generated, energy switching and electrical noise typically add unwanted high frequency spikes back into the signal. In addition, the pulsing of the sinusoidal bursts may induce high frequency components in the signal. By filtering the signal just before it reaches the electrodes, a smoother, cleaner signal is applied to the patient, thereby reducing the pain and discomfort felt by the patient and allowing a higher amplitude to be applied to the patient. This allows a sufficiently strong signal to be applied to reach a deeper nerve, such as the vagus nerve, without causing too much pain and discomfort to the patient at the surface of their skin.
Referring now to
Stimulator 200a comprises a cover 210a for protecting electrodes 204a, 206a from the external environment. Cover 210 also ensures that electrodes 204a, 206a will not contact a patient’s tissue when the device is not intended to be used (e.g., in the event that the device is accidently turned ON and electric current is passed through electrodes when not in use). In certain embodiments, cover 210a is rotatably coupled to housing 202a such that it can be moved between a first position (
Housing 202a preferably includes curved side surfaces 216a, 218a with substantially planar surfaces 220a therebetween to form an overall disc-like shape that is cut off on the upper portion of the disc. A control panel 240a may be included on one of the side surfaces 216a. Control panel 240a includes a number of user controls and/or device status indicators. In alternative embodiments, the controls and status indicators are located on a separate device, such as a mobile device, that is wirelessly (e.g. Bluetooth or the like) coupled to stimulator 200a.
In a preferred embodiment, control panel 240a includes intensity controls 242a for controlling the level of intensity or amplitude of the electrical impulses generated by stimulator 200a. Intensity controls 242a extend outward from side surfaces 216a so that the user may tactically identify and control intensity controls 242a.
Control panel 240a may further comprise a battery life indicator and/or a dose duration indicator (not shown). These indicators may include, for example, LEDs or other light sources, to facilitate identification by the user.
Stimulator 200a may further include a power control 250a for turning ON the device. Power control 250a may also include an LED or other light source for illuminating power control 250a when the device has been turned ON. In one embodiment, power control 250a is located on planar surfaces 220a, although it will be understood that power control 250a may be located on control panel 240a or elsewhere on stimulator 200a.
In certain embodiments, stimulator 200a further includes a charging pad (not shown) coupled to a suitable connector for providing power to stimulator 200a and/or recharging the battery within stimulator 200a. The charging pad may comprise any suitable charging source, such as an inductive charging source that provides power via inductive transmission through the lower surface 228a of housing 202a. Stimulator 200 may further include a gel pad (not shown) that includes a conductive gel positioned to contact electrodes 204a, 206a when gel pad is positioned over upper surface 229a.
Referring now to
In certain embodiments, sensor 380 comprises a heart pulse sensor that detects the heart pulse of the patient when the sensor 380 is placed in contact with, or near, the outer skin surface of the patient. As discussed above, the heart pulse sensor detects that the sensor is close to, or adjacent, a source of heart pulse, such as the carotid artery in the patient’s neck or the radial artery in the wrist. The heart pulse sensor may be any suitable sensor known in the art, for detecting the heart pulse of a patient, such as an infrared sensor, optical sensor, tactile sensor, a photoplethysmography (PPG) sensor or the like. The heart pulse sensor may, for example, detect the change in volume of a blood vessel that occurs when the heart pumps blood. Alternatively, the heart pulse sensor may detect vibrations, sounds or other indications that the sensor 380 is located adjacent to, or near, the patient’s heart pulse.
Sensor 380 is configured to generate an output that indicates the proximity of a heart pulse in the patient. The output may be generated and transmitted via wire, wirelessly, or waveguide, to a control unit within stimulator 300, a mobile device, processor, server, or other logic or computing device. This output provides an indication that electrodes 304, 306 are positioned optimally to modulate the target nerve, e.g., the vagus nerve.
Stimulator 300 further includes a position indicator 390 coupled to sensor 380, the control until within stimulator 300, or a separate device, and configured to provide indication of the position of the stimulator relative to the heart pulse within the patient. As discussed above, position indicator is configured to generate an alert when sensor 380 has detected the target nerve. The alert may be, for example, a visual, tactile or audial alert, that provides the user with an indication that the sensor 380 has detected the target location.
In certain embodiments, position indicator 380 is configured to transmit an alert that is associated with the magnitude of the heart pulse. In other embodiments, position indicator 390 is further be configured to provide a second alert when the magnitude of the heart pulse reaches a threshold level associated with optimal positioning of the sensor 380 and/or electrodes 304, 306.
Stimulator 200 may include additional sensors, such as, for example, biosensors, feedback sensors, chemical sensors, optical sensors, acoustic sensors, vibration sensors, motion sensors, fluid sensors, radiation sensors, temperature sensors, motion sensors, proximity sensors, fluid sensors, or others. The sensors may generate an output, such as one or more outputs, which are communicated, via wire, wirelessly or waveguide, to the stimulator 200, a mobile device, processor, server, or other logic or computing device. The output may be used as an input to one or more of the foregoing devices to forecast or avert an imminent onset or predicted upcoming onset of a symptom, episode, condition or disease. For example, as disclosed in U.S. Pat. App. Pub. No. 2017/0120052, which is incorporated herein by reference in its entirety for at least these purposes as if copied and pasted herein, as disclosed herein, and for all purposes as if copied and pasted herein, such as all structures, all functions, and all methods of manufacture and use, as disclosed therein.
In use, upper surface 399 of stimulator 300 is positioned near the outer skin surface 405 of the neck of the patient such that electrodes 304, 306 are in contact with surface 405. In certain embodiments, sensor 380 (not shown in
In certain embodiments, sensor 380 detects the magnitude of the heart pulse and generates a signal associated with such magnitude. In these embodiments, the user may elect to continue to reposition stimulator 300 until the magnitude of the heart pulse reaches a threshold level. Indicator 390 may be configured to provide a second alert to the user that such position has been reached.
Stimulation may be performed on the left or right vagus nerve or on both of them simultaneously and alternately. The position and angular orientation of the device are adjusted about that location until the patient perceives stimulation when current is passed through the stimulator electrodes. The applied current is increased gradually, first to a level wherein the patient feels sensation from the stimulation. The energy is then increased, but is set to a level that is less than one at which the patient first indicates any discomfort. Straps, harnesses, or frames may be used to maintain the stimulator in position. The stimulator signal may have a frequency and other parameters that are selected to produce a therapeutic result in the patient, i.e., stimulation parameters for each patient are adjusted on an individualized basis. Ordinarily, the amplitude of the stimulation signal is set to the maximum that is comfortable for the patient, and then the other stimulation parameters are adjusted.
The stimulation is then performed with a sinusoidal burst waveform like that shown in
Referring now to
The display 410, which can present in monochrome, grayscale, or color, indicates a status of the neurostimulator 400, such as on, off, charging, dosage amount total, dosage amount remaining, stimulation time total, stimulation time remaining, or others. The display 410 can be of any type, such as a segment display, a liquid crystal display (LCD), an electrophoretic display, a field emission display (FED), or others, whether rigid, elastic, resilient, bendable, or flexible. The display 410 can be configured to receive a touch-input, including a gesture, a slide, or others.
The cap 414 is mounted to the housing 402, such as via snug fit, friction, fastening, mating, adhering, or others. The cap 414 is transparent, but can be opaque. The cap 414 covers and protects the electrodes 404, 406 from mechanical damage, interference, moisture, or others. The control button(s) 416 are operably coupled to the signal generator and is thereby configured to increase or decrease an intensity of the stimulation by controlling the signal generator. The control button(s) 416 can be a mechanical buttons or a touch-enabled surfaces, which can be haptic or configured to receive a touch input, a slide input, a gesture input, or others. The neurostimulator 400 can be charged via a charging station (not shown), whether in a wired, wireless, or waveguide manner.
Stimulator 400 further includes a sensor 480 preferably located between electrodes 404, 406, although it will be recognized that sensor 480 may be positioned in other locations on housing 402. For example, sensor 480 may be positioned on one of the side surfaces of housing 402, on the bottom surface of housing 402, or electrodes 404, 406 may be positioned closer together such that sensor 480 is positioned on either side of electrodes 404, 406.
In certain embodiments, sensor 480 comprises a heart pulse sensor that detects the heart pulse of the patient when the sensor 480 is placed in contact with, or near, the outer skin surface of the patient. As discussed above, the heart pulse sensor detects that the sensor is close to, or adjacent, a source of heart pulse, such as the carotid artery in the patient’s neck or the radial artery in the wrist.
Stimulator 400 further includes a position indicator 490 coupled to sensor 480, the control until within stimulator 400, or a separate device, and configured to provide indication of the position of the stimulator relative to the heart pulse within the patient. As discussed above, position indicator is configured to generate an alert when sensor 480 has detected the target nerve. The alert may be, for example, a visual, tactile or audial alert, that provides the user with an indication that the sensor 380 has detected the target location.
Neurostimulator 400 can be a multi-use, hand-held, rechargeable, portable device comprising of a rechargeable battery, a set of signal-generating and amplifying electronics, and a control button for operator control of a signal amplitude. The device provides visible (display) and audible (beep) feedback on the device and stimulation status. A pair of stainless steel surfaces, which are a set of skin contact surfaces, allows a delivery of an electrical signal. The patient applies an electrode gel to the contact surfaces to maintain an uninterrupted conductive path from the contact surfaces to the skin on the neck of the patient. The stimulation surfaces are capped when not in use. The neurostimulator 400 can produce a low voltage electric signal including about five 5,000 Hz electric pulses (or less or more) that are repeated at a rate of 25 Hz (or less or more). A waveform of the electric pulses is approximately a sine wave with a peak voltage limited to about 24 volts (or less or more) when placed on the skin of the neck of the patient and a maximum output current of 60 mA (or less or more). The signal is transmitted through the skin of the neck to the vagus nerve. The neurostimulator 400 allows the patient to appropriately position and adjust a stimulation intensity as instructed a healthcare provider. Further details of appropriate waveforms and electrical signals and how to generate and transmit such signals to a desired nerve can be found in U.S. patents 8,874,205; 9,333,347; 9,174,066; 8,914,122 and 9,566,426, which are incorporated herein in their entireties by reference for at least these purposes as if copied and pasted herein, as disclosed herein, and for all purposes as if copied and pasted herein, such as all structures, all functions, and all methods of manufacture and use, as disclosed therein. Each dose can be applied for two minutes, after which the neurostimulator automatically stops delivering the neurostimulation. The neurostimulator 400 can allow for single or multiple uses or sessions. The neurostimulator can deliver a fixed number of treatments within a 24-hour period (or less or more). Once a maximum daily number of treatments has been reached, the neurostimulator 400 will not deliver any more treatments until a following 24-hour period expires. The neurostimulator can be charged via a charging station. The neurostimulator can allow for a fixed number of treatments within a defined time period, such as thirty one days or ninety three days, or some other period of time. A more complete description of systems for initially provisioning and refilling stimulator 400 can be found in U.S. Patent Application Serial No. 16/229,299, filed Dec. 22, 2017, the complete disclosure of which is incorporated herein by reference for all purposes.
Another embodiment of an electrode-based stimulator 500 is shown in
A dome 520 also protrudes from the housing, so as to allow the device to lie more or less flat on a table when supported also by the electrode surfaces. The dome also accommodates a relatively tall component that may lie underneath it, such as a battery. Alternatively, the stimuluation device may be energed by the smartphone’s battery. The belly 522 of the housing protrudes to a lesser extent than the electrodes and dome. The belly accommodates a printed circuit board that contains electronic components within the housing (not shown), as described below.
Stimulator 500 may also comprise a position sensor (not shown), such as one of the sensors describe above. The position sensor may, for example, be located in dome 520, or belly 522 of the housing. A more complete description of a stimulator for use with a mobile device can be found in commonly-assigned US Pat. No. 9,375,571, the complete disclosure of which is incorporated herein by reference for all purposes.
In some embodiments, the signal waveform (
In some embodiments, the waveform is first conveyed by the software application to contacts within the phone’s speaker output or the earphone jack socket, as though the waveform signal were a generic audio waveform. That pseudo-audio waveform will generally be a stereo waveform, representing signals that are to be applied to the “left” and “right” electrodes. The waveform will then be conveyed to the housing of the stimulator. as follows. The housing of the stimulator may have an attached dangling audio jack that is plugged into the speaker output or the earphone jack socket whenever electrical stimulation is to be performed, or the electrical connection between the contacts of the speaker output or the earphone jack socket and the housing of the stimulator may be hard-wired. In either case, electrical circuits on a printed circuit board located under the belly of the housing of the stimulator may then shape, filter, and/or amplify the pseudo-audio signal that is received via the speaker output or earphone jack socket. An energy amplifier within the housing of the stimulator may then drive the signal onto the electrodes, in a fashion that is analogous to the use of an audio energy amplifier to drive loudspeakers. Alternatively, the signal processing and amplification may be implemented in a separate device that can be plugged into sockets on the phone and/or housing of the stimulator, to couple the software application and the electrodes.
In addition to passing the stimulation waveform from the smartphone to the stimulator housing as described herein, the smartphone may also pass control signals to the stimulator housing. Thus, the stimulation waveform may generally be regarded as a type of analog, pseudo-audio signal, but if the signal contains a signature series of pulses signifying that a digital control signal is about to be sent, logic circuitry in the stimulator housing may then be set to decode the series of digital pulses that follows the signature series of pulses, analogous to the operation of a modem.
Many of the steps that direct the waveform to the electrodes, including steps that may be controlled by the user via the touchscreen, are implemented in the above-mentioned software application. By way of example, the software application may be written for a phone that uses the Android operating system. Such applications are typically developed in the Java programming language using the Android Software Development Kit (SDK), in an integrated development environment (IDE), such as Eclipse [Mike WOLFSON. Android Developer Tools Essentials. Sebastopol, California: O’Reilly Media Inc., 2013; Ronan SCHWARZ, Phil Duston, James Steele, and Nelson To. The Android Developer’s Cookbook. Building Applications with the Android SDK, Second Edition. Upper Saddle River, NJ : Addison-Wesley, 2013, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein; Shane CONDER and Lauren Darcey. Android Wireless Application Development, Second Edition. Upper Saddle River, NJ : Addison-Wesley, 2011; Jerome F. DIMARZIO. Android - A Programmer’s Guide. New York: McGraw-Hill. 2008. pp. 1-319, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein]. Application programming interfaces (APIs) that are particularly relevant to the audio features of such an Android software application (e.g., MediaPlayer APIs) are described by: Android Open Source Project of the Open Handset Alliance. Media Playback, at web domain developer.android.com with subdomain /guide/topics/media/, Jul. 18, 2014, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein. Those APIs can be relevant to a use of the smartphone camera capabilities, as described below. Additional components of the software application are available from device manufacturers [Samsung Mobile SDK, at web domain developer.samsung.com with subdomain /samsung-mobile-sdk, Jul. 18, 2014, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein].
In some embodiments, the stimulator and/or smartphone will include a user control, such as a switch or button, that disables/enables the stimulator. Preferably, the switch will automatically disable some, many, most, or all smartphone functions when the stimulator is enabled (and vice versa). This ensures that the medical device functionality of the smartphone is completely segregated from the rest of the phone’s functionality. In some embodiments, the switch will be password-controlled such that only the patient/owner of the stimulator/phone will be able to enable the stimulator functionality. In one such embodiment, the switch will be controlled by a biometric scan (e.g., fingerprint, optical scan or the like) such that the stimulator functionality can only be used by the patient. This ensures that only the patient will be able to use the prescribed therapy in the event the phone is lost or stolen.
The stimulator and/or phone can also include software that allows the patient to order more therapy doses over the internet (discussed in more detail below in connection with the docking station). The purchase of such therapy doses will require physician authorization through a prescription or the like. To that end, the software can include an authorization code for entry in order for the patient to download authorization for more therapies. In some embodiments, without such authorization, the stimulator will be disabled and will not deliver therapy.
Although the device shown in
In some embodiments, the stimulator housing may be designed as part of a protective or decorative case for the phone that can be attached to the phone, similar to standard phone cases. In one such embodiment, the stimulator/case may also include additional battery life for the phone and may include an electrical connection to the phone’s battery to recharge the battery (e.g., part of a Mophie® or the like). This electrical connection may also be used to couple the smartphone to the stimulator.
In some embodiments, significant portions of the control of the vagus nerve stimulation reside in controller components that are physically separate from the housing of the stimulator. In these embodiment, separate components of the controller and stimulator housing generally communicate with one another wirelessly, although wired or waveguide communication is possible. Thus, the use of wireless technology avoids the inconvenience and distance limitations of interconnecting cables.
First, the stimulator may be constructed with the minimum number of components needed to generate the stimulation pulses, with the remaining components placed in parts of the controller that reside outside the stimulator housing, resulting in a lighter and smaller stimulator housing. In fact, the stimulator housing may be made so small that it could be difficult to place, on the stimulator housing’s exterior, switches and knobs that are large enough to be operated easily. Instead, the user may generally operate the device using the smartphone touchscreen.
Second, the controller 130 may be given additional functions when free from the limitation of being situated within or near the stimulator housing. For example, one may add to the controller a data logging component that records when and how stimulation has been applied to the patient, for purposes of medical recordkeeping and billing. The complete electronic medical record database for the patient may be located far from the stimulator (e.g., somewhere on the internet), and the billing system for the stimulation services that are provided may also be elsewhere, so it would be useful to integrate the controller into that recordkeeping and billing system, using a communication system that includes access to the internet or telephone networks.
Third, communication from the databases to the controller would also be useful for purposes of metering electrical stimulation of the patient, when the stimulation is self-administered. For example, if the prescription for the patient only permits only a specified amount of stimulation energy to be delivered during a single session of vagus nerve stimulation, followed by a wait-time before allowing the next stimulation, the controller can query the database and then permit the stimulation only when the prescribed wait-time has passed. Similarly, the controller can query the billing system to assure that the patient’s account is in order, and withhold the stimulation if there is a problem with the account.
Fourth, as a corollary of the previous considerations, the controller may be constructed to include a computer program separate from the stimulating device, in which the databases are accessed via cell phone or internet connections.
Fifth, in some applications, it may be desired that the stimulator housing and parts of the controller be physically separate. For example, when the patient is a child, one wants to make it impossible for the child to control or adjust the vagus nerve stimulation. The best arrangement in that case is for the stimulator housing to have no touchscreen elements, control switches or adjustment knobs that could be activated by the child. Alternatively, any touchscreen elements, switches and knobs on the stimulator can be disabled, and control of the stimulation then resides only in a remote controller with a child-proof operation, which would be maintained under the control of a parent or healthcare provider.
Sixth, in some applications, the particular control signal that is transmitted to the stimulator by the controller will depend on physiological and environmental signals that are themselves transmitted to and analyzed by the controller. In such applications, many of the physiological and environmental signals may already be transmitted wirelessly, in which case it is most convenient to design an external part of the controller as the hub of all such wireless activity, including any wireless signals that are sent to and from the stimulator housing.
With these considerations in mind, an embodiment of can include a mobile device that may send/receive data to/from the stimulator, and may send/receive data to/from databases and other components of the system, including those that are accessible via the internet (or another network such as local area, wide area, satellite, cellular). Typically, the mobile device will be a laptop computer attached to additional components needed for it to accomplish its function. Thus, prior to any particular stimulation session, the mobile device may load into the stimulator parameters of the session, including waveform parameters, or the actual waveform.
In some embodiments, the mobile device is also used to limit the amount of stimulation energy that may be consumed by the patient during the session, by charging the stimulator’s rechargable battery with only a specified amount of releasable electrical energy, which is different than setting a parameter to restrict the duration of a stimulation session. Thus, the mobile device may comprise a energy supply that may be connected to the stimulator’s rechargable battery, and the mobile device meters the recharge. As a practical matter, the stimulator may therefore use two batteries, one for applying stimulation energy to the electrodes (the charge of which may be limited by the mobile device) and the other for performing other functions. Methods for evaluating a battery’s charge or releasable energy can be as disclosed in patent US7751891, entitled Energy supply monitoring for an implantable device, to ARMSTRONG et al, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein. Alternatively, some control components within the stimulator housing may monitor the amount of electrode stimulation energy that has been consumed during a stimulation session and stop the stimulation session when a limit has been reached, irrespective of the time when the limit has been reached.
The communication connections between different components of the stimulator’s controller are shown in
Although infrared or ultrasound wireless control might be used to communicate between components of the controller, they are not preferred because of line-of-sight limitations. Instead, the communication between devices preferably makes use of radio communication within unlicensed ISM frequency bands (260 - 470 MHz, 902 - 928 MHz, 2400 - 2.4835 GHz). Components of the radio frequency system in devices in 331, 332, and 333 typically comprise a system-on-chip transciever with an integrated microcontroller; a crystal; associated balun & matching circuitry, and an antenna [Dag GRINI. RF Basics, RF for Non-RF Engineers. Texas Instruments, Post Office Box 655303, Dallas, Texas 75265, 2006, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein].
Transceivers based on 2.4 GHz offer high data rates (greater than 1 Mbps) and a smaller antenna than those operating at lower frequencies, which makes them suitable for with short-range devices. Furthermore, a 2.4 GHz wireless standard (e.g., Bluetooth, Wi-Fi, and ZigBee) may be used as the protocol for transmission between devices. Although the ZigBee wireless standard operates at 2.4 GHz in most jurisdictions worldwide, it also operates in the ISM frequencies 868 MHz in Europe, and 915 MHz in the USA and Australia. Data transmission rates vary from 20 to 250 kilobits/second with that standard. Because many commercially available health-related sensors may operate using ZigBee, its use may be recommended for applications in which the controller uses feedback and feedforward methods to adjust the patient’s vagus nerve stimulation based on the sensors’ values, as described below in connection with
A 2.4 GHz radio has higher energy consumption than radios operating at lower frequencies, due to reduced circuit efficiencies. Furthermore, the 2.4 GHz spectrum is crowded and subject to significant interference from microwave ovens, cordless phones, 802.11 b/g wireless local area networks, Bluetooth devices, etc. Sub-GHz radios enable lower energy consumption and can operate for years on a single battery. These factors, combined with lower system cost, make sub-GHz transceivers ideal for low data rate applications that need maximum range and multi-year operating life.
The antenna length needed for operating at different frequencies is 17.3 cm at 433 MHz, 8.2 cm at 915 MHz, and 3 cm at 2.4 GHz. Therefore, unless the antenna is included in a neck collar that supports the device shown in
Range is determined by the sensitivity of the transceiver and its output energy. A primary factor affecting radio sensitivity is the data rate. Higher data rates reduce sensitivity, leading to a need for higher output energy to achieve sufficient range. For many applications that require only a low data rate, the preferred rate is 40 Kbps where the transceiver can still use a standard off-the-shelf 20 parts per million crystal.
A signal waveform that might be transmitted wirelessly to the stimulator housing was shown in
However, because it is contemplated that sensors attached to the stimulator housing may also be transmitting information, the data transfer requirements may be substantially greater than what is required only to transmit the signal shown in
When a patient is using the stimulation device to perform self-stimulation therapy, e.g., at home or at a workplace, he or she will follow the steps that are now described. It is assumed that the optimal stimulation position has already been marked on the patient’s neck, as described above and that a reference image of the fluorescent spots has already been acquired. The previous stimulation session will ordinarily have discharged the rechargeable batteries of the stimulator housing, and between sessions, the mobile device will have been used to recharge the stimulator at most only up to a minimum level. If the stimulator’s batteries had charge remaining from the previous stimulation session, the mobile device will discharge the stimulator to a minimum level that will not support stimulation of the patient.
The patient can initiate the stimulation session using the mobile phone or mobile device (e.g., laptop computer) by invoking a computer program (on the laptop computer or through an app on the mobile phone) that is designed to initiate use of the stimulator. The programs in the smartphone and mobile device may initiate and interact with one another wirelessly, so in what follows, reference to the program (app) in the smartphone may also apply to the program in the mobile device, because both may be operating in tandem. For security reasons, the program would begin with the request for a user name and a password, and that user’s demographic information and any data from previous stimulator experiences would already be associated with it in the login account. The smartphone may also be used to authenticate the patient using a fingerprint or voice recognition app, or other reliable authentication methods. If the patient’s physician has not authorized further treatments, the mobile device will not charge the stimulator’s batteries, and instead, the computer program will call or otherwise communicate with the physician’s computer requesting authorization. After authorization by the physician is received, the computer program (on the laptop computer or through an app on the mobile phone) may also query a database that is ordinarily located somewhere on the internet to verify that the patient’s account is in order. If it is not in order, the program may then request prepayment for one or more stimulation sessions, which would be paid by the patient using a credit card, debit card, PayPal, cryptocurrency, bitcoin, or the like. The computer program will also query its internal database or that of the mobile device to determine that sufficient time has elapsed between when the stimulator was last used and the present time, to verify that any required wait-time has elapsed.
Having received authorization to perform a nerve stimulation session, the patient interface computer program will then ask the patient questions that are relevant to the selection of parameters that the mobile device will use to make the stimulator ready for the stimulation session. The questions that the computer program asks are dependent on the condition for which the patient is being treated, which for present purposes is considered to be treatment for an autoimmune disease or disorder. The questions may be things like (1) is this an acute or prophylactic treatment? (2) if acute, then how severe is your pain and in what locations, how long have you had it, (3) has anything unusual or noteworthy occurred since the last stimulation? etc.
Having received such preliminary information from the patient, the computer programs will perform instrument diagnostic tests and make the stimulator ready for the stimulation session. In general, the algorithm for setting the stimulator parameters will have been decided by the physician and will include the extent to which the stimulator batteries should be charged, which the vagus nerve should be stimulated (right or left), and the time that the patient should wait after the stimulation session is ended until initiation of a subsequent stimulation session. The computer will query the physician’s computer to ascertain whether there have been any updates to the algorithm, and if not, will use the existing algorithm. The patient will also be advised of the stimulation session parameter values by the interface computer program, so as to know what to expect.
Once the mobile device has been used to charge the stimulator’s batteries to the requisite charge, the computer program (or smartphone app) will indicate to the patient that the stimulator is ready for use. At that point, the patient would clean the electrode surfaces, and make any other preliminary adjustments to the hardware. The stimulation parameters for the session will be displayed, and any options that the patient is allowed to select may be made. Once the patient is ready to begin, he or she will press a “start” button on the touchscreen and may begin the vagus nerve stimulation.
Multiple methods may be used to test whether the patient is properly attempting to stimulate the vagus nerve (or another nerve or organ or muscle or bone) on the intended side of the neck (or another portion of a human body). For example, accelerometers and gyroscopes within the smartphone may be used to determine the position and orientation of the smartphone’s touch screen relative to the patient’s expected view of the screen, and a decision by the stimulator’s computer program as to which hand is being used to hold the stimulator may be made by measuring capacitance on the outside of the stimulator body, which may distinguish fingers wrapped around the device versus the ball of a thumb [Raphael WIMMER and Sebastian Boring. HandSense: discriminating different ways of grasping and holding a tangible user interface. Proceedings of the 3rd International Conference on Tangible and Embedded Interaction, pp. 359-362. ACM New York, NY, 2009, the disclosure of which is incorporated herein by reference for all purposes as if copied and pasted herein]. Pressing of the electrodes against the skin will result in a resistance drop across the electrodes, which can initiate operation of the rear camera. A fluorescent image should appear on the smartphone screen only if the device is applied to the side of the neck in the vicinity of the fluorescent spots that had been applied as a tattoo earlier. If the totality of these data indicates to the computer program that the patient is attempting to stimulate the wrong vagus nerve or that the device is being held improperly, the stimulation will be withheld, and the stimulator may then communicate with the patient via the interface computer program (in the mobile phone or laptop computer) to alert the patient of that fact. T
Before logging off of the interface computer program, the patient may also review database records and summaries about all previous treatment sessions, so as to make his or her own judgment about treatment progress. If the stimulation was part of a prophylactic treatment regimen that was prescribed by the patient’s physician, the patient interface computer program will remind the patient about the schedule for the upcoming self-treatment sessions and allow for a rescheduling if necessary.
For some patients, the stimulation may be performed for as little as 60 seconds, but it may also be for up to 30 minutes or longer. The treatment is generally performed once or twice daily or several times a week, for 12 weeks or longer before a decision is made as to whether to continue the treatment. For patients experiencing intermittent symptoms, the treatment may be performed only when the patient is symptomatic. However, it is understood that parameters of the stimulation protocol may be varied in response to heterogeneity in the pathophysiology of patients. Different stimulation parameters may also be used as the course of the patient’s condition changes.
Selected nerve fibers are stimulated in different embodiments of methods that make use of the disclosed electrical stimulation devices, including stimulation of the vagus nerve at a location in the patient’s neck.
Of course, it will be recognized that the vagus nerve may be stimulated through other mechanisms. For example, auricular vagal nerve stimulation involves stimulation of the auricular branch of the vagus nerve, often termed the Alderman’s nerve or Arnold’s nerve. This nerve may be stimulated through the transcutaneous systems and methods described herein by transmitting electrical impulses through the outer skin surface of the patient’s ear to the auricular branch of the vagus nerve.
Referring now to
In still another embodiment, pulse generator 716 and energy source 712 are coupled to each other, either wirelessly, via wired connections, or directly in a housing that contains both components. This housing may, for example, include a wireless transmitter and may be worn by the patient in manners known to those skilled in the art, so that the signal can be transmitted from the housing to electrodes 714.
System 700 further includes a controller 718 that is coupled to stimulator 702 and may be used to select or set parameters for the stimulation protocol (amplitude, frequency, pulse width, burst number, electrode positioning etc.), the treatment regimen discussed above (i.e., duration and number of doses, etc.) or alert the patient as to the need to use or adjust the stimulator (i.e., an alarm). Controller 718 may be directly coupled to stimulator 702 via wired connectors or within the same housing, or it may be wirelessly coupled to stimulator 702.
Significant portions of the control of the vagus nerve stimulation may reside in controller components that are physically separate from stimulator 702. In this embodiment, separate components of the controller 718 and stimulator 702 generally communicate with one another wirelessly. Thus, the use of wireless technology avoids the inconvenience and distance limitations of interconnecting cables.
In certain embodiments, system 700 may further include a mobile device 720 that either couples controller 718 to stimulator 702 or vice versa. Mobile device 720 may comprise a mobile phone, such as a smartphone, a smartwatch, iPad, laptop computer or any other mobile device having a computing function and wireless transmission technology.
In addition to position sensors 711, system 700 may further include one or more additional sensors (not shown) used for detecting certain physiological parameters of the patient based on the stimulation of the nerve. The preferred sensors will include ones ordinarily used for ambulatory monitoring. For example, the sensors may comprise those used in conventional Holter and bedside monitoring applications, for monitoring heart rate and variability, ECG, respiration depth and rate, core temperature, hydration, blood pressure, brain function, oxygenation, skin impedance, and skin temperature. The sensors may be embedded in garments or placed in sports wristwatches, as currently used in programs that monitor the physiological status of soldiers [G.A. SHAW, A.M. Siegel, G. Zogbi, and T.P. Opar. Warfighter physiological and environmental monitoring: a study for the U.S. Army Research Institute in Environmental Medicine and the Soldier Systems Center. MIT Lincoln Laboratory, Lexington MA. 1 Nov. 2004, pp. 1-141]. The ECG sensors should be adapted to the automatic extraction and analysis of particular features of the ECG, for example, indices of P-wave morphology, as well as heart rate variability indices of parasympathetic and sympathetic tone. Measurement of respiration using noninvasive inductive plethysmography, mercury in silastic strain gauges or impedance pneumography is particularly advised, in order to account for the effects of respiration on the heart. A noninvasive accelerometer may also be included among the ambulatory sensors, in order to identify motion artifacts. An event marker may also be included in order for the patient to mark relevant circumstances and sensations.
For brain monitoring, the sensors may comprise ambulatory EEG sensors [CASSON A, Yates D, Smith S, Duncan J, Rodriguez-Villegas E. Wearable electroencephalography. What is it, why is it needed, and what does it entail? IEEE Eng Med Biol Mag. 29(3,2010):44-56] or optical topography systems for mapping prefrontal cortex activation [Atsumori H, Kiguchi M, Obata A, Sato H, Katura T, Funane T, Maki A. Development of wearable optical topography system for mapping the prefrontal cortex activation. Rev Sci Instrum. 2009 Apr;80(4):043704]. Signal processing methods, comprising not only the application of conventional linear filters to the raw EEG data, but also the nearly real-time extraction of non-linear signal features from the data, may be considered to be a part of the EEG monitoring [D. Puthankattil SUBHA, Paul K. Joseph, Rajendra Acharya U, and Choo Min Lim. EEG signal analysis: A survey. J Med Syst 34(2010):195-212]. In the present application, the features would include EEG bands (e.g., delta, theta, alpha, beta).
For any given position of the stimulator relative to the vagus nerve, it is also possible to infer the amplitude of the electric field that it produces in the vicinity of the vagus nerve. This is done by calculation or by measuring the electric field that is produced by the stimulator as a function of depth and position within a phantom that simulates the relevant bodily tissue [Francis Marion MOORE. Electrical Stimulation for pain suppression: mathematical and physical models. Thesis, School of Engineering, Cornell University, 2007; Bartosz SAWICKI, Robert Szmurło, Przemystaw Płonecki, Jacek Starzyński, Stanisław Wincenciak, Andrzej Rysz. Mathematical Modelling of Vagus Nerve Stimulation. pp. 92-97 in: Krawczyk, A. Electromagnetic Field, Health and Environment: Proceedings of EHE′07. Amsterdam, IOS Press, 2008]. Thus, in order to compensate for movement, the controller may increase or decrease the amplitude of the output from the stimulator (u) in proportion to the inferred deviation of the amplitude of the electric field in the vicinity of the vagus nerve, relative to its desired value.
Various corresponding structures, materials, acts, and equivalents of all means or step plus function elements in various claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. Various embodiments were chosen and described in order to best explain various principles of this disclosure and various practical applications thereof, and to enable others of ordinary skill in a pertinent art to understand this disclosure for various embodiments with various modifications as are suited to a particular use contemplated.
Various diagrams depicted herein are illustrative. There can be many variations to such diagrams or steps (or operations) described therein without departing from various spirits of this disclosure. For instance, various steps can be performed in a differing order or steps can be added, deleted or modified. All of these variations are considered a part of this disclosure. People skilled in an art to which this disclosure relates, both now and in future, can make various improvements and enhancements which fall within various scopes of various claims which follow.
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