Patent Application
20160206877
1. Field of the Invention
The present invention relates generally to the field of applying stimulating energy to tissues for stimulating a brain, and to therapeutic methods thereof. More specifically, the present invention relates to the use of brain stimulation methods in alleviating symptoms, treating conditions, and/or altering brain function associated with central sensitivity.
2. Description of Related Art
It is known to stimulate tissues such as those of the brain, spinal cord or the vagus nerve as a means of providing therapy for a number of disorders, including nociceptive pain. A known method of delivery for such stimulation involves surgically implanting a signal generating device within the tissues of a subject.
It is also known to stimulate tissues by delivering stimulation energy to such tissues from external sources such as electromagnetic energy and electrical signal generators, and relying on tissue electrical properties to either induce or conduct such stimulation energy.
Central sensitivity (CS), also known as central sensitization, central pain, central augmentation, and central hypersensitivity among other terms, is an increased responsiveness of pain transmission to neurons in the spinal cord that is usually caused by neurochemical changes in the spinal cord, brainstem, or forebrain. CS mechanisms in the brain have been implicated in the pathology of allodynia, which is the term used when pain is caused by a stimulus that does not normally provoke pain; and in hyperalgesia, which is the term used when pain perceived from a stimulus is greater than what would normally be expected from that stimulus. Put simply, in central sensitivity the brain magnifies painful stimuli and eventually magnifies even associated non-painful stimuli. As pointed out in Latremoliere and Woolfe (6), because CS results from changes in the properties of neurons in the central nervous system, the pain is no longer coupled, as acute nociceptive pain is, to the presence, intensity, or duration of noxious peripheral stimuli arising from both neuropathic and inflammatory sources. Further, in chronic pain conditions the increased excitability due to CS far outlasts the initiating noxious stimulus, that is, the nociceptive input that causes the pain to occur in the first place.
Before CS was discovered, typically only two models of pain were contemplated. The first envisioned mechanisms by which specific pain pathways are activated by peripheral pain stimuli, and that the amplitude and duration of the pain experienced was determined entirely by the intensity and timing of the peripheral pain inputs. The second model suggested gate controls in the central nervous system that open and close, thus enabling or preventing pain. Medical science now recognizes CS as a third and unique model that contemplates neuroplastic changes in the functional properties of the central nervous system that lead to reductions in pain threshold, increases in the magnitude and duration of responses to noxious input, and permits normally innocuous inputs to generate pain sensations. In addition, CS is also believed to be relevant in somatic symptoms associated with painful conditions, including but not limited to fatigue and sleep disorders.
The brain's role in CS is being increasingly revealed and understood in neuroscience, due in large part to the advent of functional brain imaging technologies. For example, Lee et al. (7) used functional magnetic resonance imaging (fMRI) to examine the extent that brain activity contributes to the maintenance of CS in humans. When the intensity of pain during CS and normal states were matched, activity within the brainstem, including the mesencephalic pontine reticular formation and the anterior thalami, remained increased during CS. Regarding brain areas related to the consequence of increased pain perception during CS, cortical activity mainly in the primary somatosensory area has been significantly correlated with intensity of pain attributable to both the force of noxious stimulation used and state in which noxious stimulation was applied.
Borsook et al. (8) reviewed the literature on brain activity using neuroimaging technologies. Their review details evidence of alterations in multiple sub-cortical and cortical processing mechanisms, including sensory, emotional/affective, cognitive, and modulatory systems that are present in chronic pain. The authors note these findings provide evidence of an increasing and important role of numerous brain regions in the centralization of chronic pain and the contribution to the altered brain in chronic pain conditions. Similarly, Schweinhardt and Bushnell (9) review neuroimaging evidence that the brain plays an active and enhanced modulatory role for pain processing in chronic pain patients, citing findings that brain activations in chronic pain involve brain circuitry not normally activated by acute pain.
Because of this emerging understanding, the role of CS is increasingly shown to be pathological in seemingly unrelated chronic pain conditions and syndromes including fibromyalgia, complex regional pain syndrome, phantom pain, and migraine headaches. Yunus (10) identifies no less than 14 common syndromes that lack structural pathology yet have CS as a common mechanism. These conditions further include chronic fatigue syndrome, irritable bowel syndrome, tension-type headaches, temporomandibular disorder, myofascial pain syndrome, regional soft-tissue pain syndrome, restless leg syndrome, periodic limb movements in sleep, multiple chemical sensitivity, primary dysmenorrhea, female urethral syndrome, interstitial cystitis, and post-traumatic stress disorder. Yunus also notes that CS may play a significant role in the pain of depression and in Gulf War Syndrome.
Giesecke et al. (11) used fMRI to demonstrate augmented central pain processing in patients with idiopathic chronic low back pain and fibromyalgia. Indeed, when equal levels of mechanical pressure intended to elicit a painful response were applied to patients and normal controls, patients with chronic low back pain and fibromyalgia experienced significantly more pain and showed more extensive, common patterns of neuronal activation in pain-related cortical areas of the brain than the controls. Thus, CS may play an important role in persons with chronic low back pain that persists without identifiable physical pathology.
The role of CS in persistent inflammatory conditions is also gaining recognition. In Gwilym et al. (12), fMRI illustrated significantly greater brain activation in osteoarthritis (OA) patients in response to stimulation of their referred pain areas (i.e. areas where pain persists but do not exhibit OA or related inflammation) compared with healthy controls, and the magnitude of this activation positively correlated with the extent of neuropathic-like elements to the patient's pain. The role of CS in osteoarthritis has been the subject of several other investigations (13, 14). As detailed in Imamura et al. (15), the refractory, disabling pain associated with knee OA is usually treated with total knee replacement. However, a comparison of OA patients with healthy normal controls showed patients with knee OA had significantly lower pressure pain thresholds (PPT) over widespread evaluated structures beyond the knee. The lower PPT values were correlated with higher pain intensity, higher disability scores, and with poorer quality of life. This suggests pain in these patients might be more associated with CS rather than peripheral inflammation and injury. As the authors point out, the implications of the role of CS, and its potential for modulation, may provide exciting and innovative cost effective therapeutic tools to control pain, reduce disability, and improve quality of life in knee OA patients.
Yet, the treatment of CS is a challenging task. As stated by Latremoliere and Woolfe (6), “The complexity is daunting because the essence of central sensitization is a constantly changing mosaic of alterations in membrane excitability, reductions in inhibitory transmission, and increases in synaptic efficacy, mediated by many converging and diverging molecular players on a background of phenotypic switches and structural alterations.” Some centrally-acting pharmaceutical agents such as gabapentin (16,17), ketamine (18), propofol (19) and anti-tumor necrosis factor alpha (TNF-alpha) therapy (20), just to name a few, have evidence of efficacy in treating CS. The patent literature has examples in the art of pharmaceutical use as a therapeutic agent for treating CS. For example, the use of dimiracetam for treatment of hyperalgesia and allodynia caused by central sensitization in chronic pain has been taught. Further, the use of compounds associated with (R)-2-acetamido-N-benzyl-3-methoxypropionamide have been taught to treat central neuropathic pain, including “neurological disorders characterized by persistence of pain and hypersensitivity in a body region.”
The following references are incorporated by reference in their entirety:
According to the invention, a method is provided for alleviating symptoms associated with central sensitivity in a subject. The method includes the steps of selecting a subject suffering from one or more symptoms associated with central sensitivity and stimulating a target region of the brain of the subject to stimulate pathological brain activity associated with central sensitivity, and thereby alleviate symptoms associated with central sensitivity.
Also, according to the invention, a method is provided for alleviating symptoms associated with central sensitivity in a subject where the method comprises the steps of determining the presence of central sensitivity in the subject, identifying at least one target region of the subject's brain as being related to the central sensitivity, and stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region thereby alleviating symptoms associated with central sensitivity.
Also, according to the invention, a method is provided for alleviating symptoms associated with central sensitivity in a subject where the method includes the steps of selecting a subject suffering from one or more symptoms associated with central sensitivity, stimulating a target region of a brain of the subject to stimulate pathological brain activity associated with central sensitivity, and administering one or more pharmaceutical agents to the subject to further augment the alleviating of symptoms associated with central sensitivity.
Also, according to the invention, a method is provided for alleviating symptoms associated with central sensitivity in a subject where the method includes the steps of determining the presence of central sensitivity in the subject, identifying at least one target region of the subject's brain involved in the central sensitivity, stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region, and administering one or more pharmaceutical agents to the subject to further augment the alleviating of symptoms associated with central sensitivity.
Also, according to the invention, a method is provided for treating a condition associated with central sensitivity in a subject where the method includes the steps of selecting a subject suffering from one or more conditions associated with central sensitivity and stimulating a target region of the brain of the subject to stimulate pathological brain activity associated with central sensitivity, and to thereby treat a condition associated with central sensitivity.
Also, according to the invention, a method is provided for treating a condition associated with central sensitivity in a subject where the method includes the steps of determining the presence of central sensitivity in the subject, identifying at least one target region of the subject's brain as being involved in the central sensitivity, and stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region thereby treating a condition associated with central sensitivity.
Also, according to the invention, a method is provided for treating a condition associated with central sensitivity in a subject where the method includes the steps of selecting a subject suffering from one or more conditions associated with central sensitivity, stimulating a target region of a brain of the subject to stimulate pathological brain activity associated with central sensitivity, and administering one or more pharmaceutical agents to the subject to further augment the treating of a condition associated with central sensitivity.
Also, according to the invention, a method is provided for treating a condition associated with central sensitivity in a subject where the method includes the steps of determining the presence of central sensitivity in the subject, identifying at least one target region of the subject's brain related to the central sensitivity, stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region, and administering one or more pharmaceutical agents to the subject to further augment the treating of a condition associated with central sensitivity.
Also, according to the invention, a method is provided for altering brain activity associated with central sensitivity in a subject where the method includes the steps of selecting a subject suffering from brain activity associated with central sensitivity and stimulating a target region of the brain of the subject to stimulate pathological brain activity associated with central sensitivity, thereby altering a brain activity associated with central sensitivity.
Also, according to the invention, a method is provided for altering brain activity associated with central sensitivity in a subject where the method includes the steps of determining the presence of brain activity associated with central sensitivity in the subject, identifying at least one target region of the subject's brain as being involved in the brain activity associated with central sensitivity, and stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region thereby altering a brain activity associated with central sensitivity.
Also, according to the invention, a method is provided for altering brain activity associated with central sensitivity in a subject where the method includes the steps of selecting a subject suffering from brain activity associated with central sensitivity, stimulating a target region of a brain of the subject to stimulate pathological brain activity associated with central sensitivity, and administering one or more pharmaceutical agents to the subject to further augment the altering of a brain activity associated with central sensitivity.
Also, according to the invention, a method is provided for altering brain activity associated with central sensitivity in a subject where the method includes the steps of determining the presence of brain activity associated central sensitivity in the subject, identifying at least one target region of the subject's brain related to the central sensitivity, stimulating the at least one target region of the brain of the subject to stimulate pathological brain activity in the at least one target region, and administering one or more pharmaceutical agents to the subject to further augment the altering of a brain activity associated with central sensitivity.
Additional advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become more apparent to those skilled in the art upon examination of the following or upon learning by practice of the invention.
For a more complete understanding of the present invention, the needs satisfied thereby, and the features, and advantages thereof, reference now is made to the following description taken in connection with the accompanying drawings.
An apparatus for treating neurological dysfunctions is shown in
In the following description of the disclosed apparatus and methods, the term “central sensitivity” is intended to mean any central nervous system condition pathologically related to hyperalgesia, allodynia, reductions in pain threshold, increases in the magnitude and duration of responses to noxious input, results in normally innocuous inputs to generate pain sensations, or results in non-painful symptoms associated with increases in central nervous system responsiveness. Central sensitivity is also known by alternate terms that may include but are not limited to “central sensitization”, “central pain”, “central augmentation,” and “central hypersensitivity”.
Central sensitivity is not a manifestation or cause of an individual symptom or condition. Instead, central sensitivity results in a worsening of the effect or magnitude of one or more symptoms because of a central nervous system condition that is independent of the cause of the one or more symptoms per se. Thus, any method of treatment of central sensitivity is fundamentally different from treatment of a specific symptom. For example, treatment of pain augmentation by central sensitivity is inherently different than treatment of pain under traditional nociceptive models of pain.
The term “alleviate” or “alleviating” is intended to mean any outcome in which a condition and/or its symptoms are reduced, made less severe, mitigated, treated or eliminated for any period of time.
The term “stimulating” is intended to mean the transmission of any energy signal that is generated by a stimulation device such as an electrical stimulator or a magnetic stimulator including a transcranial magnetic stimulator, to the brain of a subject for the purpose of influencing any function or physiological state of the subject's brain that is at least one part of a pathway of central sensitivity.
The term “stimulation signal” is intended to mean any energy signal used in the process of stimulating a tissue such as a brain.
The term “pathway of central sensitivity” is intended to mean any aspect of the central nervous system, including at least one or more portions of the brain, the spinal cord or peripheral nerves, which is functionally involved, related to, or affects the process of central sensitivity.
The term “symptoms associated with central sensitivity” is intended to mean any symptom manifestation or similar indication that is known in the art to be associated with central sensitivity. Such symptoms include, but are not limited to, pain, musculoskeletal pain, pain at multiple sites, generalized hyperalgesia, stiffness, swollen feeling in soft tissues, fatigue, poor sleep, paresthesia, anxiety, chronic headaches, tension headaches, dysmenorrhea, irritable bowel syndrome, periodic limb movements, symptoms of restless leg syndrome, depression, symptoms of Sjögren's syndrome, symptoms of Raynaud's Phenomenon, symptoms of female urethral syndrome, impaired memory, impaired concentration, cognitive impairment, tender cervical lymph nodes, tender axillary lymph nodes, post-exertion malaise, tender points, sensory hypersensitivity, sleep disturbances, immune dysfunction, history of viral illness, neurohormonal dysfunction, neuroendocrine dysfunction and/or a lack of macroscopic or microscopic pathological findings in peripheral tissues.
The term “neuroimaging test” is intended to mean any medical test that provides visual indication, measures, or data that can be used to make an assessment about central nervous system function, including brain function. A neuroimaging test includes, but is not limited to, magnetic resonance imaging, computer aided tomography, positron emission tomography, or single photon emission computed tomography, and may also include brain electrical function tests such as electroencephalography or magnetoencephalography.
The terms “central sensitivity alleviating or treatment agent” and “central sensitivity symptom alleviating or treatment agent” are intended to mean any pharmaceutical agent selected from group of centrally-acting pharmaceutical agents that includes, but is not limited to, analgesics, opioids, antidepressants, anticonvulsants, or drugs designed to influence the expression or uptake of certain neurotransmitters such as serotonin, norepinephrine or dopamine.
The term “conditions associated with central sensitivity” is intended to mean any medical conditions that are known in the art to be associated with central sensitivity. Such conditions include, but are not limited to, chronic pain of unknown origin, fibromyalgia, osteoarthritis, depression, complex regional pain syndrome, phantom pain, chronic fatigue syndrome, irritable bowel syndrome, functional dyspepsia, migraine headaches, tension-type headaches, temporomandibular disorder, myofascial pain syndrome, regional soft-tissue pain syndrome, restless leg syndrome, periodic limb movements, multiple chemical sensitivity, primary dysmenorrhea, female urethral syndrome, interstitial cystitis, premenstrual tension syndrome, vulvodynia, Sjögren's syndrome, Raynaud's Phenomenon, post-traumatic stress disorder, Gulf War Syndrome, chronic low back pain and mild traumatic brain injury.
The term “brain activities” is intended to mean any brain activity known in the art to be associated with central sensitivity. Such brain activities include, but are not limited to, abnormal function, abnormal response, abnormal regions of activation, abnormal network connectivity, abnormal release of neurochemicals, abnormal uptake of neurochemicals, abnormal electrical activity, or abnormal metabolism.
The term “optical unit” is intended to define an apparatus that is used on or in close proximity to the eyes. “Close proximity” means a distance from the eyes of a subject that is effective for the transmittal of a light pulse into the eyes of the subject. Preferably, close proximity will not exceed one foot in distance from the subject. The structure of the optical unit may be worn on the face of the patient, such as optical device or goggles, or it may be located in a separate structure, such as a stand that is held near the face or even a hand-held mask. Further, the optic unit may be placed at an angle to the eyes of the subject. Additionally, the optic unit may be positioned behind the subject and use mirrors or other reflective devices (such as a white wall) to reflect the light pulse into the eyes of the subject. However, in no way is this definition intended to limit the ultimate structure the optical unit may take.
The term “neurological dysfunction” is intended to define a group of disorders in which one or more regions of a subject's brain operate at frequencies that are different from the predetermined frequency for that region of the brain or from the predetermined frequencies of the other regions of the subject's brain. Examples of neurological dysfunctions include traumatic brain injury, post traumatic stress disorder, post stroke paralysis, post traumatic brain injury paralysis, cerebral palsy, headache, depression, post chemotherapy cognitive, mood and fatigue disorder, fibromyalgia, memory loss, coma, attention deficit disorder, etc. However, the disclosed apparatus and methods are not to be construed as being limited to the treatment of these listed examples.
The term “irregular activity” is intended to define the EEG frequency of a region of the subject's brain which does not match the predetermined EEG activity of the remaining regions of the subject's brain. Additionally, the term “irregular activity” is also intended to define an EEG frequency of a region of the subject's brain that matches the EEG activity of the remaining regions of the subject's brain, but with a high degree of variance. Irregular activity is determined by analyzing the frequency bands of the region of the brain being investigated and identifying either a higher band amplitude or a lower band amplitude than is predetermined for that region. Examples of potential irregular activity include amplitude abnormalities in which the measured peak-to-peak microvolts is over 14 microvolts (abnormally high) or in which the measured microvolts is under 5 microvolts from peak-to-peak (abnormally low) or possesses a standard deviation of over 3 microvolts. However, these are examples only. One of ordinary skill would recognize what a proper benchmark would be for each subject.
The term “neurostimulation signal” is intended to define a signal transmitted by the neurostimulator to a subject for the purpose of normalizing the brainwave activity of regions of the subject's brain that possess irregular activity. The neurostimulation signal is determined on a subject by subject basis and is changed in relation to a shift in the region's dominant frequency. There is typically a reduction in variability as EEG changes occur. This is evidenced by a shift in the dominant frequency more towards the typical frequencies and amplitudes that were predetermined for that region of the subject's brain.
The term “normalization” is intended to define the result of the administration of a neurostimulation signal to regions of the subject's brain that correspond to the regions of the subject's brain that possess irregular activity. The neurostimulation signal is intended to “normalize” or adjust the brainwave frequency of the regions of the subject's brain that possess irregular activity to reflect the predetermined frequency of the region of the subject's brain that is being treated.
The term “dominant frequency” is intended to define the frequency in the EEG measurements taken from an area of the subject's brain that possesses the highest voltage amplitude.
The disclosed apparatus and methods are directed towards the alleviation of neurological disorders caused by irregular activity in a subject's brain or by abnormal brain activities. The alleviation of neurological disorders is accomplished by administering a neurostimulation signal to the regions of the subject's brain that are related to those regions of the subject's brain that possess irregular activity or abnormal brain activities. These related regions of the subject's brain can include regions that possess irregular activity, abnormal brain activities, or other regions of the brain. One of skill in the neurological arts would recognize which regions of the brain are interrelated with other regions of the brain.
For example, in one method of choosing the treatment sites, the choice is determined by the regions of EEG-slowing specific to an individual, regardless of the diagnosis. In this method, it is the presence and pattern of EEG-slowing at any of the standard neurological 10-20 sites (as selected by the International 10-20 EEG Site Placement Standard) that is the indication of the appropriateness of a region of the brain for treatment. The EEG-slowing pattern also determines where on the scalp electrodes will be placed for treatment.
Because EEG slowing that is associated with fatigue, poor short-term memory, and attention problems is likely to involve functional deficits in the left frontal lobes of the brains, placing electrodes on any of the following sites is a reasonable directive: FP1, F7, F3, C3, F1, AF7, F5, AF3 and possibly temporal sites, T3 & T5 (according to the International 10-20 EEG Site Placement Standard). The amplitudes and standard deviations from the image data determine the order of treatment for these sites.
The imaging data is preferably gathered by sequentially recording from each of 21 sites. These data are preferably processed through a Fast Fourier Transform (FFT) computation which produces quantitative data that shows the average microvolts and the standard deviation for each frequency component of the EEG signal at each site. A preferred method of treatment is to identify those sites that have the highest standard deviation as shown in the FFT results and treat them first. Treatment can be accomplished by placing two pairs of electrodes (one positive and one negative comprise a pair) on each of the four sites having the highest measured amplitudes.
It is the unique EEG pattern of the individual, however, that is the key to the most efficient treatment. The determination of treatment sites applies to any diagnostic category of neurological dysfunction and the determination is individualized by the quantitative data from each individual's brainwave data. Therefore, it is not possible to specify a standard set of sites for any given, or all, diagnostic categories. However, there is a broad diagnostic classification called EEG-slowing and that this category can permit the selection of predetermined sites from which to direct the treatment of choice. Therefore, given the above information one of ordinary skill would understand how to select a region of the brain for treatment on a subject by subject basis.
The neurostimulation signal is administered by modulating a high frequency component, which can be further pulse-width modulated for control of the energy level, with a low frequency carrier. It is intended that, according to at least one embodiment, the brain's electrical activity is to be “disentrained”, that is, to redistribute existing energy to all frequencies in the normal spectra of the brain EEG in a typically uniform manner rather than targeting or locking into a particular frequency. The neurostimulation signal may also be used for the purposes of entrainment.
According to one preferred embodiment, a method is provided for focusing a neurostimulation signal directly on a suspected dysfunctional region of a subject's brain. This is possible because tissue impedances are minimized by the design of the neurostimulation signal. The neurostimulation signal possesses a greater ability to directly reach damaged regions of the brain rather than simply following the outer-most tissues around the scalp and thereby bypassing the damaged region of the brain. Another advantage is achieved by inducing the neurostimulation signal directly into EEG sensors. This advantage is that the neurostimulation signal can be strategically placed to present a conduction path through the damaged region of the brain, while concurrently measuring the EEG signal at the dysfunctional regions, thus providing a direct link between the measured EEG signals and the neurostimulation signals being delivered directly to the dysfunctional region.
Further according to this preferred embodiment, the treatment of a subject may include the generation of an electrical neurostimulation signal characterized by a high frequency pulse train modulated by a low frequency carrier signal. Variable levels of electrical power may be provided by using either pulse width modulation of the high frequency pulse train, as in the preferred embodiment, or variable amplitudes of the same pulses. Preferably, the frequency of the high frequency pulse train is at least one order of magnitude greater than the frequency of the low frequency carrier signal. It is preferred that the high frequency pulse be in the range of 43 to 1,000,000 hertz. It is more preferred that the high frequency pulse be in the range of 1,000 to 100,000 hertz. It is further preferred that the high frequency pulse be in the range of 10,000 to 20,000 hertz. It is most preferred that the high frequency pulse be 15,000 hertz.
The low frequency carrier signal is variably related to critical frequency components of the EEG power spectral density, determined from statistical analysis of amplitudes and variability. The low frequency carrier signal is determined from information obtained by measuring EEG activity at a reference site or sites that generally corresponds with the location of suspected brain dysfunction, and the low frequency carrier signal is dynamically changed as a function of time to prevent entrainment. This is performed by changing the frequency offset (as described below) at predetermined time intervals. It is preferred that the low frequency carrier signal be typical of a brainwave EEG. It is more preferred that the low frequency carrier signal be in the range of 1-42 hertz.
The combination of (1) the high frequency pulse train as it is modulated by (2) the low frequency carrier signal, henceforth referred to as an AMPWM signal, provides a means of minimizing the effect of tissue impedances of the head. However, no limitation to AMPWM signals alone is intended by this abbreviation. Any signal that possess both (1) and (2) as defined above may be used according to the preferred embodiment.
In general, as will be discussed in greater detail in subsequent sections of this disclosure, the electrical impedance of tissues of the head decreases with increased electrical signal frequency. Thus, the high frequency pulse train component of the AMPWM signal passes through the head tissues with less attenuation than the low frequency carrier signals typically used in already known neurostimulation methods. Further, the low frequency carrier signal component of the neurostimulation signal in essence serves to turn on and off the high frequency signal component with a frequency that is generally related to the range of frequencies present in an EEG signal. Thus, the low frequency carrier signal component may be produced at frequencies commonly used for therapeutic purposes in neurostimulation devices, such as entrainment or disentrainment.
Some neurological dysfunctions that may be treated with the disclosed apparatus and/or in accordance with one or more of the disclosed methods, include traumatic brain injury, post traumatic stress disorder, post stroke paralysis, post traumatic brain injury paralysis, cerebral palsy, headache, depression, post chemotherapy cognitive, mood and fatigue disorder, fibromyalgia, memory loss, coma, attention deficit disorder, etc. However, this list is not intended to be exclusive.
One or more of the disclosed methods may preferably include the taking of a first measurement of the EEG of a subject afflicted with at least one type of the neurological dysfunction in order to obtain EEG results and evaluating the obtained EEG results to determine whether any region of the subject's brain possesses irregular activity as compared to other regions of the subject's brain. It is preferred that the subject be a mammal and, more preferably, a primate. It is most preferred that the subject be a human being. It is also preferred that the irregular activity be determined by comparing the EEG signals from a region of the subject's brain with the EEG signals from the remaining regions of the subject's brain. It is also preferred that the EEG signals are obtained from more than one region of the subject's scalp. It is further preferred that the EEG signals be obtained from at least 21 regions of the subject's scalp that correspond to 21 regions of the subject's brain. It is further preferred that the regions be selected according to the International 10-20 EEG Site Placement Standard.
A determination of a dominant frequency of the subject's brain may be made by evaluating the EEG results from the regions of the subject's brain that possess irregular activity. Preferably, the evaluation may involve the correlation of the EEG signals into a graphic image of the subject's brain. Preferably, the graphic image may be evaluated and new EEG signals from the subject's brain may be taken in order to ensure that the first EEG signals were accurate and/or in order to determine a dominant frequency from the regions of the subject's brain that have been confirmed as possessing irregular activity.
Finally, one or more of the disclosed methods may comprise an administration of an anti-neurological dysfunction therapy to a subject. Such an anti-neurological dysfunction therapy may comprise the inducement of a neurostimulation signal that may be directed to targeted regions of the subject's brain that possess irregular activity, and that may be continued for a time sufficient to normalize the EEG signals of the regions of the subject's brain that possess irregular activity.
Preferably, the signal may be directed to the targeted regions of the subject's brain for between one second and one hour. It is more preferred that the signal be directed to the targeted regions for between 1 and 30 minutes. It is even more preferred that the signal be directed to the targeted regions for between 1 minute and 10 minutes. It is even more preferred still that the signal continue to be so directed for between 1 minute and 3 minutes. It is still more preferred that the signal continue to be so directed for between 1 second and 30 seconds. It is most preferred that the signal continue to be so directed for between 1 second and five seconds.
Additionally, further EEG signal measurements from the targeted regions of the subject's brain, e.g., the regions that possess irregular activity, may be monitored during the administration of the therapy and the neurostimulation signal may be adjusted based on any detected changes in the additional EEG signal measurements. The normalization of the EEG signals from the regions of the subject's brain that possess irregular activity has been demonstrated to result in an alleviation of the symptoms of the neurological disorders.
The neurostimulation signal may comprise a carrier frequency that may comprise a dominant frequency and a frequency offset. Preferably, the frequency offset may be between −10 and 20 hertz.
It is preferred that the normalization of the regions of the subject's brain that possess irregular activity result in these regions transmitting EEG signals that are close to the predetermined frequency and amplitude expected for those regions of the subject's brain. It is also preferred that these regions transmit EEG signals at the predetermined frequency and amplitude expected for those regions of the subject's brain after the treatment.
The subject may require multiple exposures to the method in order to achieve an alleviation of the symptoms he or she suffers from the neurological dysfunctions. It is preferred that the multiple exposures remain in the range of 1 to 40 exposures. However, more exposures are permitted, if required. It is more preferred that the exposures remain in the range of 10 to 30 exposures. It is more preferred that the exposures remain in the range of 5 to 10 exposures. Additionally, it is preferred that a repeated use of the method be avoided within 24 hours of a previous use of the method. However, if required, it is possible to treat more than one region of the subject's brain (if more than one region of the subject's brain possesses irregular activity) in one treatment session.
Additionally, the subject may be medicated, sedated, or unconscious during the administration of the method. However, it is preferred that the subject be in none of these conditions.
Regarding the application of the neurostimulation signal itself, after the identification of regions the subject's brain which possess irregular activity, neurostimulation treatment is accomplished by placing EEG sensors in an arrangement that allows for the measurement of the EEG activity from the dysfunctional region, as well for providing a successful delivery of current from the EEG sensors into a system ground. The apparatus may be computer-controlled and programmed to acquire EEG signal data from the sensor sites and to analyze the EEG signal data to determine the frequency of the low frequency carrier signal component of the AMPWM signal.
The AMPWM signal can be transmitted to the subject through a plurality of neurostimulation delivery modes. Preferably, the mechanism or method of delivery is to induce the AMPWM signal into the EEG sensors through inductive coupling. Another preferred for delivering the AMPWM signal to the subject is to use the AMPWM signal to drive a light-generating component, such as a light emitting diode, to provide a photic stimulation signal that may be delivered to the patient through the optic nerve.
Stimulation delivery may be accomplished by inducing the AMPWM signal into the EEG sensors through inductive coupling while simultaneously driving a light-generating component, such as a light emitting diode, to provide a photic stimulation signal. In essence, this is a combination of previously discussed methods.
Lastly, EEG leads may preferably be placed on the scalp of a subject. This may be done regardless of what stimulation method is used because the apparatus and methods preferably provide for EEG measurement to be made during stimulation delivery. The apparatus and methods also include the use of these EEG measurements to drive neurostimulation signal parameters.
The delivery mode for a neurostimulation signal may be selectable to account for different levels of sensitivity and tolerance in patients. The process of transmitting the neurostimulation signal and the monitoring of the EEG signal data from the EEG sensors may be automated.
As stated above, the EEG signals from the subject may preferably be measured at, typically, 21 different scalp locations and power spectral density computations may preferably be performed on the obtained EEG signals. These computations break the measured analog EEG signals into frequency domain data such as a Fourier series of discrete frequency components, which is limited to 1-42 Hertz (greater signal components exist and could be utilized, but the 1-42 Hertz range is typically considered clinically useful). However, other methods of obtaining the frequency domain data are acceptable (such as the use of wavelet analysis).
In analyzing EEG signal data, frequency bands may be used. For example, the “delta” band is typically 1-4 Hertz; the “theta” band is 5-7 Hertz, and so on. For each site, the total amplitude associated with each discrete frequency component is assigned to proper bands, providing a measure of the EEG band energy for each of the aforementioned sites. From this, a graphic “image” is generated where colors represent amplitudes. From this image, the clinician can see EEG band activity related to regions of the brain, and based on clinical knowledge, can determine if a region has unusual or abnormal activity.
Accordingly, the neurostimulation phase of the disclosed methods (i.e. treatment) is administered to correct regions of abnormal brain activity. The administration of the neurostimulation signal is preferably performed after the imaging process described above is completed. The clinician preferably applies EEG sensors to regions of the scalp that relate to the regions of suspected dysfunction and the EEG signal data is preferably re-measured for a period long enough to provide power spectral density data (as in the imaging process). The frequency domain data is then sorted and the frequency that exhibits the highest amplitude is designated the “dominant frequency”. According to clinician chosen stimulation time and frequency parameters, a neurostimulation signal is generated that has a “carrier frequency” that is determined by the formula: CARRIER FREQUENCY=DOMINANT FREQUENCY+FREQUENCY OFFSET.
The parameters the clinician uses are (1) stimulation intensity, (2) the times that the stimulation signal is turned on in the treatment cycle (as well as the number of times), (3) the duration that each stimulation signal is turned on, the leading frequency of each stimulation event, and (4) the phase offset of each stimulation event. Intensity is defined by the pulse-width-modulation duty cycle, and ranges from 0 (no “on-time”) to 100% (no “off-time”). Thus, an intensity of 50% would have a duty cycle such that “on-time” is equal to “off-time” in each pulse cycle. The number of stimulation cycles and the times that the stimulation turns on is entirely clinician driven. However, it is preferred ranges that the stimulation cycles range between 1 stimulation event up to 50. It is preferred, however, that no more than 20 different stimulation events be used per session. The preferred leading frequency is already defined to range between −10 and 20 Hz. Preferred Phase offset ranges from −180 to 180 Hz.
In this formula, “frequency offset” is preferably selected from the range of −40 to 40 Hertz and more preferably from −10 and 20 Hertz.
The offset is chosen by clinical experience, therefore, one of ordinary skill in the art would recognize how to choose an offset. However, the clinician generally picks the largest offset (i.e., +20 Hz) to see if a response is elicited. If no response is elicited, lower offsets will be tried until a response is obtained. The clinician's choice of parameter values is typically driven by a selection of choices that cause the subject to react, yet do not cause an “over-reaction” which is an adverse effect characterized by short-term fatigue, headache, etc.
All of the preferred neurostimulation parameters to be considered are defined below. Values of these parameters are chosen based on clinician experience, and are selected in a manner that is meant to cause a reactive therapeutic effect without causing the subject to over-react. The selection of these values is further driven by subject condition and symptomatic presentation. For example, a subject with mild traumatic brain injury may be able tolerate a longer (in duration) than average stimulation application without suffering an adverse effect. However, a subject with fibromyalgia with severe fatigue may only tolerate a very short (in duration) stimulation burst at the lowest intensities possible. The ranges of values for these parameters are provided for the clinician to choose based on experience, patient condition and symptomatic presentation, thus no preferred or optimal values exist. These parameters include:
Intensity—This is a measure of the pulse width modulation signal's duty cycle. This provides a variation on the time-averaged current delivered to the stimulation mechanisms (i.e. the EEG lead inducing circuit and the photic stimulators).
Duration—This is a measure the time in seconds that a neurostimulation event (i.e. a period of stimulation signal output) lasts. This can range from 1 second to 1,200 seconds in the preferred embodiment.
Start Time—This is the time in seconds after the beginning of a neurostimulation treatment session begins when a neurostimulation event starts to occur. There is no specific limitation on this, that is, the start time could begin at any time after the treatment session begins. Before the start time occurs, the system is simply measuring EEG and this could, theoretically, go on indefinitely.
Leading Frequency and Phase Offset are previously defined.
By adding the frequency offset to the dominant frequency, a carrier frequency is created that is always different than the dominant frequency. This neurostimulation signal is then either induced in the EEG sensors attached to the subject's scalp or the neurostimulation signal is used to drive light emitting diodes for photic stimulation purposes. The duration of the signal, along with other parameters (as described above) such as intensity and phase offset (in the case of LEDs for photic stimulation—a phase offset causes the LEDs to flash out of synchronization with each other) are determined by the clinician's chosen treatment protocol.
As described above, the neurostimulation signal can be an amplitude modulated pulse-width modulation signal. A graphic representation of the signal is shown in
Regarding the apparatus,
In this formula, the resistance is given by the nomenclature R, capacitance by C and frequency by f. This equation clearly shows that as the frequency of the signal increases, the overall impedance of the system decreases despite the level of impedance from the resistor 1 being constant. Although the impedances of the composite tissues of the head are considerably more complex and require a far more sophisticated model to accurately describe current flows, this model provides a simple analogy and approximately describes the effect, and is a fundamental basis for the present disclosure.
The effects of applying electrical energy to brain tissues, e.g., as a neurostimulation signal, are well established in the medical literature and in other teachings, and will not be expounded upon here.
As shown in
As shown in
The neurostimulator 9 may further comprise a series of electrical conductors such as EEG sensors 11. The EEG sensors 11 may be configured to be attached to a subject, to monitor EEG signals of the subject, and/or to administer neurostimulation signals to the subject. Additionally, each EEG sensor 11 may comprise contact electrodes 25 that may be disposed at the ends, and may include at least one positive lead 12, one negative lead 13 and one ground lead 14.
Employing multiple sets of the EEG sensors 11 simultaneously and multiple biopotential acquisition devices 15 can accomplish acquisition of EEG signals from multiple sites on the scalp. For clarity, the apparatus is described herein for acquisition of EEG signal from one scalp site. One or more of the EEG sensors 11 may be connected to the neurostimulator 9 via electrical connectors such as the EEG sensor connectors 17.
The neurostimulator 9 may therefore comprise a biopotential acquisition device 15 that may comprise an electric circuit configured to acquire biopotential data such as from the EEG signals obtained by the EEG sensors 11 attached to the subject. It is preferred that the subject be a mammal. It is further preferred that the subject be a primate and further preferred that the subject be a human being.
Additionally, the neurostimulator 9 may comprise an inductor 32 that may be configured and positioned to act as a transformer, whereas the stimulation signal may be induced in the neurostimulator 9 by inducing electrical current into the inductor 32, which further induces electrical current in the EEG sensors 11 via electromagnetic coupling, and thereby into the subject.
The neurostimulator 9 may further comprise an optical unit, as shown at 16 in
With further reference to
The neurostimulator 9 preferably internally comprises the biopotential acquisition device 15 and the biopotential acquisition device 15 is preferably designed to acquire biopotential data such as from EEG signal data, specifically patient EEG, to provide a means for analysis and data storage of the biopotential data through computational means, generate a neurostimulation signal and deliver the neurostimulation signal to the patient.
EEG signals may be acquired with EEG sensors 11 attached to a patient's scalp. The contact electrodes 25 may be located at the ends of the EEG sensors 11 in positions to be attached to the patient. The EEG signal is delivered to the neurostimulator 9 via the EEG sensors 11, connected to the biopotential acquisition device 15 through EEG lead connectors 17, and operatively coupled to a biopotential acquisition device 15. To minimize the effect of external electrical noise, any number of filtering units 26 may be employed in the preferred embodiment. To assure patient safety, the biopotential data are passed through the isolation amplifier 27. The output of the biopotential data, after passing through the biopotential acquisition device 15, filters 26 and isolation amplifier 27 is acquired by the microcontroller 28 through analog-to-digital ports 29. The microcontroller 28 is operatively coupled to the computing device 8. One method of coupling the microcontroller 28 to the computing device is to use a peripheral cable 10. Control of the neurostimulator 9 is accomplished by communication between the microcontroller 28 and the computing device 8. Further, the objective of biopotential data analysis and storage is accomplished computationally via communication between the microcontroller 28 and the computing device 8.
After analysis of the acquired biopotential data such as the EEG signal, the computing device 8 may communicate proper stimulation signal parameters to the microcontroller 28. These parameters may include signal energy level, frequency of the low frequency component of an AMPWM signal, phase offset of multiple signals, start time, frequency offset and duration through a user interface. Utilizing a digital-to-analog port 30 on the microcontroller 28, the stimulation signal is output from the microcontroller 28 to transistors 31 or similar switching devices capable of managing the current levels of the stimulation signal. Depending on the mode of stimulation chosen by a clinician, the stimulation signal will be routed to the different means of stimulation signal delivery, alone or in combination. The parameters for the clinician's choice are set forth above.
If optical stimulation is desired, the stimulation signal will be sent to the optical unit 16 featuring the light generating devices 20 to be worn by the patient. Any unit capable of emitting light may be used as a light generating device. This includes, but is not limited to a LED, a light bulb, a low-power laser, etc. Alternately, if EEG lead 11 stimulation is desired, where the stimulation signal is delivered to the patient's scalp via the attached electrodes 25, then the stimulation signal is sent to the inductor 32, which may be configured and positioned to induce current in the EEG sensors 11 from the stimulation signal generated by the microcontroller 28. A plurality of stimulation delivery modes may be warranted to allow for clinician choice to further effect successful treatment based on individual patient needs.
To assure patient safety, all electronics in the neurostimulator 9, including the biopotential acquisition device 15, the filter 26, the isolation amplifier 27, the microcontroller 28 and the transistors 31 may be supplied electricity by the aforementioned isolation power supply 23.
Finally, regarding the coupling of the components, if a computing device is used it is preferably operatively coupled to the processor of the neurostimulator via any of a number of means of commonly used peripheral communications techniques, such as serial communication, USB port communication or parallel communication 10. All remaining electronics are preferably operatively coupled to the processing device (e.g. microcontroller) in the neurostimulator. The data acquisition circuit preferably comprises the biopotential acquisition device 15, filters 26 and isolation circuitry (amplifier) 27. The isolation amplifier is preferably coupled to an analog-to-digital input port on the microcontroller 28, via electrical conduction paths such as wires or printed circuit board conductors. The filters 26 are preferably operatively coupled to the isolation amplifier 27 via electrical conduction paths such as wires or printed circuit board conductors. Further, the biopotential acquisition device 15 is preferably operatively coupled to the filters 26 via electrical conduction paths such as wires or printed circuit board conductors.
A stimulation circuit is preferably coupled to a digital-to-analog port 30 on the microcontroller, in all cases via electrical conduction paths such as wires or printed circuit board conductors. It is preferred that an isolated power supply 23 supplies all operative power for neurostimulation outputs such as that to the optical device 16 or the EEG lead stimulation inducing circuitry 32. Electrical output from the digital-to-analog port 30 is preferably conducted to a transistor 31 that is further coupled to the isolated power supply 23. When a signal is received at the base of the transistor 31 from the microcontroller 28, the transistor operates to switch on electricity from the isolated power supply 23 which is further conducted via electrical coupling to the inductor (stimulation inducing circuitry) 32. Current flow in the inductor 32 induces a current in the EEG lead, as described in the specification.
Alternately, for photic stimulation, the isolated power supply 23 is preferably coupled via electrical coupling to two more transistors 31, which are preferably operatively coupled via electrical coupling to independent digital-to-analog ports 30 on the microcontroller 28. Electricity conducted from the digital-to-analog ports 30 to the base of the transistors 31 in the photic stimulation circuit has the effect of switching on these transistors, further allowing for conduction of electricity to the photic stimulation devices, such as LEDs 21. The photic stimulation devices are preferably coupled to the transistors 31 via electrical connectors 19, thus providing for current flow to the photic stimulation devices such as LEDs 21.
Finally, it is preferred that the apparatus operate on a 12 volt power supply. It is more preferred that the apparatus operate on a 6 volt power supply. It is most preferred that the apparatus operate on a power supply equivalent to the lowest power supply requirement of the components used.
With reference to
However, an AMPWM signal may combine signals of shapes other than square waves. For example,
An AMPWM signal may also be created from multiple relatively low frequency components. A signal with multiple frequency components can be created using methods such as inverse Fourier Transform theory.
Additional apparatus that provide for the generation of electrical tissue stimulation signals, such as AMPWM signals, that reduce tissue impedance and increase depth of signal penetration are disclosed herein. A first embodiment of a tissue stimulation apparatus for providing an electrical tissue stimulation signal that reduces tissue impedance and increases depth of signal penetration is shown in
Internally, the electrical stimulation device 101 may include a battery charger and switching circuit 107 electrically coupled to the power connector 111, enabling the receipt of electricity from the external power source 105. A battery 108 may also be electrically coupled to the battery charger and switching circuit 107. The battery 108 may further be connected to other circuits of the electrical stimulation apparatus through the battery charger and switching circuit 107 and used to provide electrical power to the other circuits at times when isolation from line current is required or advantageous for operation of the apparatus, such as in times when the apparatus is being used to provide electrical stimulation to a subject. In practice, electrical isolation may be accomplished through a switching portion of the battery charger and switching circuit 107, which may be further electrically coupled to a controller or processor 103 configured to control various functions of the electrical stimulation device 101 such as electrical signal generation and as is further described herein. Programmed firmware, associated with processor technologies, for example, may provide for electrical signals to be sent from the processor 103 to control the switching portion of the battery charger and switching circuit 107 and to electrically decouple the electrical stimulation device 101 from the external power source 105 when isolation is required or desirable. At times when isolation is not required or desirable, such components as the processor 103, external power source 105 and battery charger, and switching circuit 107 may be used to recharge the battery 108 in preparation for subsequent use. In other words, the processor 103 may be configured to command the switching portion of the battery charger and switching circuit 107 to couple the external power source 105 to the battery 108 when isolation of the electrical stimulation device 101 is not required or desirable and to decouple the external power source 105 from the battery 108 when isolation is required or desirable. This coupling may be accomplished either as a result a signal being sent to a processor 103 arising from a manual input such as the manual decoupling of an external power source 105 from line power, or automatically arising from a software signal being sent to a processor 103 whenever an operator utilizes a software interface for using the apparatus to electrically stimulate a subject. In other words, the processor 103 may be programmed to automatically decouple external power in response to an operator's use of a software interface to use the apparatus to electrically stimulate a subject.
The battery 108 or other power source may subsequently energize a power regulation circuit 109 that further provides conditioned power to other circuits of the electrical stimulation device 101 and a common reference ground that may be used by all circuits. A ground connector 112 may be used to provide electrical coupling to external circuits, such as those described herein, for common grounding purposes.
As is also shown in the embodiment of
The disclosed apparatus and methods may be implemented using hardware, software or a combination thereof and may be implemented in one or more computer systems or other processing systems. According to one embodiment, one or more computer systems capable of carrying out the functionality described herein are contemplated. An example of such computer system is shown at 200 in
The computer system 200 includes at least one processor 204 that is connected to a communication infrastructure 206 (e.g., a communications bus, cross-over bar, or network). Any suitable software embodiments may be used with this exemplary computer system, and the disclosed apparatus and methods may be implemented using any suitable computer system and/or architectures.
The computer system 200 may include a display interface 202 that forwards graphics, text, and other data from the communication infrastructure 206 or from a frame buffer (not shown) for display on a display unit 230. The computer system 200 may also include a main memory 208, preferably random access memory (RAM), and may also include a secondary memory 210. The secondary memory 210 may include, for example, a hard disk drive 212 and/or a removable storage drive 214 such as a floppy disk drive, a magnetic tape drive, or an optical disk drive, etc. The removable storage drive 214 may be configured to read from and/or writes to a removable storage unit 218 in a well-known manner. The removable storage unit 218 may include a floppy disk, magnetic tape, optical disk, etc., which may be read by and written to the removable storage drive 214. The removable storage unit 218 may include a computer usable storage medium having stored therein computer software and/or data.
In alternative embodiments, the secondary memory 210 may include other similar devices for allowing computer programs or other instructions to be loaded into computer system 200. Such devices may include, for example, a removable storage unit 222 and an interface 220. Examples of such may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an erasable programmable read only memory (EPROM), or programmable read only memory (PROM)) and associated socket, and other removable storage units 222 and interfaces 220, which allow software and data to be transferred from the removable storage unit 222 to the computer system 200.
The computer system 200 may also include a communications interface 224. The communications interface 224 may be configured to allow software and data to be transferred between the computer system 200 and external devices. The communications interface 224 may include a modem, a network interface (such as an Ethernet card), a communications port, a Personal Computer Memory Card International Association (PCMCIA) slot and card, etc. Software and data transferred via communications interface 224 are in the form of signals 228, which may be electronic, electromagnetic, optical or other signals capable of being received by communications interface 224. These signals 228 are provided to communications interface 224 via a communications path (e.g., channel) 226. This path 226 carries signals 228 and may be implemented using wire or cable, fiber optics, a telephone line, a cellular link, a radio frequency (RF) link and/or other communications channels. In this document, the terms “computer program medium” and “computer usable medium” are used to refer generally to media such as a removable storage drive 214, a hard disk installed in hard disk drive 212, and signals 228. These computer program products provide software to the computer system 200. The disclosed apparatus and methods may include such computer program products.
Computer programs (also referred to as computer control logic) are stored in main memory 208 and/or secondary memory 210. Computer programs may also be received via communications interface 224. Such computer programs, when executed, enable the computer system 200 to perform according to the features of the disclosed apparatus and methods. The computer programs, when executed, enable the processor 204 to perform according to the features of the disclosed apparatus and embodiments. Accordingly, such computer programs serve as controllers of the computer system 200.
In an apparatus or method embodiment that includes the use of software, the software may be stored in a computer program product and loaded into computer system 200 using the removable storage drive 214, the hard drive 212, or the communications interface 224. The control logic (software), when executed by the processor 204, causes the processor 204 to perform according to the functions of the disclosed apparatus and methods. The disclosed apparatus and methods may be implemented primarily in hardware using, for example, hardware components, such as application specific integrated circuits (ASICs). Implementation of the hardware state machine to perform the functions described herein will be apparent to persons skilled in the relevant art(s).
Alternatively, the disclosed apparatus and methods may be implemented using a combination of both hardware and software.
In some embodiments, and as shown in
Upon establishment of signal parameters in a processor 103, along with establishment of other operational parameters, such as the aforementioned decoupling of an external power source 105, signals are sent from the processor 103 to a D/A converter 104, whereupon an analog voltage representing an electrical signal for stimulating tissues is first achieved. The analog voltage is further provided to an electrically coupled signal conditioning and amplification circuit 106, where a substantially equivalent signal is created with advantageous enhancements such as, but not limited to, increased voltage amplitude, decreased signal-to-noise ratio, and increased current capability.
In some embodiments, provisions may be made to the electrical stimulation apparatus for the selective control of the delivery of an electrical signal for stimulating tissues to a plurality of stimulation connectors 113. A stimulation switching circuit 110 is electrically coupled to the processor 103, whereupon control signals from the processor 103 allow for the signal from the signal conditioning and amplification circuit 106 to be advantageously switched to any number of independent electrical conductors or conduction paths. Further, the independent electrical conductors or conduction paths are electrically coupled with a first ground switching circuit 119, the first ground switching circuit 119 being further electrically coupled to the processor 103. Control signals from the processor 103 allow for selective switching of the independent conductors to an apparatus ground point, providing advantageous control of the independent conductors' use as either a conduction path for an electrical signal for stimulating tissues or a ground. Further electrical conduction paths are provided for each independent conductor passing through a first ground switching circuit 119, with each independent conductor terminating at one of a plurality of stimulation connectors 113.
The apparatus may include a number of electrical conductors that provide electrical coupling between a number of connectors and input/output (I/O) ports of a processor 103 in the electrical stimulation device 101 for the embodiments shown. Specifically, an auxiliary power supply connector 114 may be provided. The apparatus may include a switch comprising an electrical conductor first connected to an auxiliary power supply connector 114 then to a switch, then via another electrical conductor to an auxiliary I/O connector 116. The switch may be used for various purposes to indicate an event to the processor 103. One exemplary purpose is the use of the switch by a subject receiving electrical stimulation to mark a point in time of any particular interest.
The electrical stimulation device 101 may also include a plurality of conductors or control I/O connectors 115 that provide electrical coupling to I/O ports of the processor 103. Specifically, the control I/O connectors 115 may provide control signals between the processor 103 and various electrical apparatus or peripheral devices coupled to the electrical stimulation device 101, examples of which are described further herein. The apparatus may further include a number of lead test ports 117 electrically coupled to the processor 103 for electrically coupling electrical conductors or other couplings, to the processor 103 for the purpose of testing the electrical conducting integrity of any combination of such electrical conductors, or other couplings, such as wires combined with sensors, such as surface electrodes, henceforth referred to as “leads”, used to conduct electrical energy between tissues and the electrical stimulation device 101.
As is also shown in
In operation, the apparatus of
The processor 103 may be programmed to provide control signals that selectively control the stimulation switching circuit 110 and the first ground switching circuit 119 to cause the leads 121 to serve as either stimulation leads delivering stimulation or as ground leads serving as ground sources in such a way as to create multiple spatial paths of electrical stimulation through tissues.
In addition, as shown in
In addition, in the apparatus shown in
As shown in
In an exemplary operation, the apparatus of
In the apparatus of
In the apparatus of
In the apparatus of
In the apparatus of
In the apparatus of
The data representing impedance of tissues and ongoing monitoring for biopotential voltage integrity, such as, but not limited to, EEG measurement integrity, may be used to determine or alter parametric values of an electrical signal for stimulating tissues, such as an AMPWM signal.
The use of methods to monitor for biopotential voltage integrity accomplishes various means of guiding a user and assuring improved biopotential signal data throughout an acquisition time period. For example, the apparatus may include an alert for notifying a user if integrity is lost during treatment. Such alert may be provided, for example, via software analysis in an external computing device 102. In another embodiment, such alert may be sent to a remote indicator such as a pager worn by a user. Further, the apparatus may include various means of indicating to a user when good biopotential voltage integrity is achieved as biopotential acquisition leads 125 and ground leads 120 are first being applied to tissues, prior to the acquisition of data. Such indicators may be provided, for example, via graphic user interface software in an external computing device 102 or via any number of hardware indication means.
With reference to
The exemplary apparatus illustrated in
In operation, the apparatus of
With reference to
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In an exemplary operation, the apparatus of
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Further, and with particular reference to
Accordingly, as shown in
The exemplary apparatus illustrated in
In operation, the apparatus of
With reference to
In operation, the tissue stimulation apparatus 144 of
In the tissue stimulation apparatus 144 shown in
In the tissue stimulation apparatus 144 shown in
In the tissue stimulation apparatus 144 shown in
In tissue stimulation apparatus such as those shown in a number of the figures, the use of leads may be dynamically altered between (a) conducting biopotential voltages, (b) conducting an electrical signal for stimulating tissues and (c) a ground, in conjunction with the use of computational analysis of the acquired data, such as biopotential data, providing indication of a region of tissue to be stimulated. Based on such analysis, sufficient leads may be identified and appropriately placed so as to provide a number of possible conduction paths passing in near proximity to the region of tissue of interest. Then, control signals from a processor 103 of an electrical stimulation device 101 may be used to selectively switch use of the leads, in accordance with methods taught herein, to provide any number of dynamically controlled conductors and grounds for an electrical signal for stimulating tissues. The electrical stimulation device 101 may then be used to deliver the electrical signal to the appropriate region of tissues and may further be used to assess subsequently acquired data for the purpose of subsequent altering of lead use. In other words, tissues of a subject may be stimulated by first providing a tissue stimulation apparatus configured to dynamically alter the use of leads between conducting biopotential voltages, conducting an electrical signal for stimulating tissues, and grounding, in response to a computational analysis of biopotential data acquired from a region of tissue to be stimulated, acquiring biopotential data from a region of tissue to be stimulated, performing a computational analysis of the acquired biopotential data, in response to the analysis, identifying and placing sufficient leads so as to provide a number of possible conduction paths passing in near proximity to a region of tissue of interest, and dynamically controlling electrical signal delivery to the region of tissue of interest by selectively switching the use of the leads as conductors and grounds. In addition subsequently acquired data may be assessed for the purpose of subsequent altering of lead use.
In place of a battery 108 any one of a number of circuit embodiments known in the art may be used to provide electrical isolation from an external power source 105 and may further be used to provide isolated electrical power to one or more circuits of the electrical stimulation device 101.
An external computing device 102 may functionally interface with other network computing devices, including but not limited to computing devices coupled to or otherwise accessible via the Internet. Such interfaces to other network computing devices may be used, for example, to facilitate the determination or alteration of parametric values of an electrical signal for stimulating tissues through analysis using software in a network computing device, with subsequent control data being sent from the network computing device via the functional interfaces to an external computing device 102, further operationally coupled to a processor 103 in an electrical stimulation device 101. In other words, the external computing device 102 may be configured to functionally interface with at least one other network computing device to determine parametric values of an electrical tissue stimulation signal; and to receive subsequent corresponding control data from the other network computing device via the functional interfaces. The external computing device 102 may be configured to functionally interface with the other network computing device via the Internet.
According to the disclosed apparatus and methods, the time-averaged current flow of an electric signal for stimulating tissues may be varied by modifying the duty cycle of the high frequency component of an AMPWM signal. This method of varying the time-averaged current flow may include varying stimulation intensity provided to a subject by an external stimulation device 123 such as, but not limited to, the light intensity of an optical stimulation device, the magnetic field strength of an electromagnetic device, the mechanical action of an electromechanical stimulation device or the sound intensity of an audio stimulation device.
The apparatus for providing electrical signals for stimulating tissues may be integrated with other instruments used during periods of therapy. For example, such instruments may be electrically coupled to an electrical stimulation device 101 through auxiliary I/O connectors 16. In other words, the tissue stimulation apparatus may include data collection instruments configured to collect data on a subject during periods of therapy and electrically coupled to the electrical stimulation device 101. Among other things, this approach allows simultaneous collection of instrument data during periods of therapy.
A software program may be used to execute various means of identifying a subject. Such means may include, but are not limited to, electronic or magnetic identification media. Such means may also include, but are not limited to, the use of digital photographs of a subject to both aid in identification of the subject and to provide visual support to aid in proper location for the placement of any leads associated with the apparatus.
Software may also be used to facilitate the playing of music through an external stimulation device 123 for the subject during therapy, with the music being chosen, for example, to enhance therapeutic effect.
Software may also be used to facilitate the playing of educational audio or video media clips for the subject at any time associated with therapy, with the media clips being chosen, for example, to enhance therapeutic effect.
A number of methods have been described for deriving quantities such as the frequency, phase, pulse width duty cycle, and amplitude of electrical signals for stimulating tissues, e.g., signals such as AMPWM signals, that reduce tissue impedance and increase depth of signal penetration. Such derivations are anticipated through either manual means such as those performed by a human, or automatic means such as those performed by computational methods in software, or by any combination of both means. In various methods taught herein, the term “frequency” refers to any singular value or to any range of values that change over a period of time during therapeutic activity (e.g. a “frequency sweep”).
Such signals may be used to stimulate brain tissue. According to one method of electrically stimulating tissue, parametric values of an electrical tissue stimulation signal are determined in response to biopotential voltage data obtained from a region of tissue to be stimulated. An electrical stimulation signal having the determined parametric values is then generated and applied to the region of tissue. One exemplary way of determining parametric signal values includes first taking a measure of the EEG activity of at least a portion of the brain, or the EEG of the entire brain, of a subject prior to the generation and application of any electrical signal for the purposes of stimulating brain tissues. Upon collection of EEG activity from the brain for a sufficient period of time, the EEG data is analyzed for any number of relationships. A sufficient period of time for collecting EEG activity may be between, for example, one second and one hour. The relationships for which the EEG data is analyzed may include, but are not limited to, the amount of measured voltage in single frequency components; in composites of multiple frequencies, also known as frequency bands; and/or in frequency band ratios, for the cases of both individual EEG sites and for multiple EEG sites. These relationships may further include, but are not limited to, various statistical analyses involving measured EEG voltages and their frequency and phase components, taken at both individual EEG sites and for multiple EEG sites. These statistical analyses may include, but are not limited to, measures of variance, correlation, and/or coherence. These relationships may further include, but are not limited to, various analyses that provide indication of the spatial origin and/or source localization of the measured EEG, such as that accomplished by performing “inverse EEG” analysis.
Parametric determination may further rely on making comparisons between the findings of the EEG analysis and similar measures known to represent normal brain activity in a healthy normal population of living beings such as human beings. Such a comparison may be performed, for example, for the purpose of quantifying differences between the measured EEG of a subject and the EEG expected in normal brain activity. Such differences are used to identify particular brain sites or regions where frequency and amplitude components of the subject's EEG are either excessive; that is, where they exhibit greater values than normal; diminished; that is, where they exhibit values lower than normal; or highly variable; that is, where they exhibit values that fluctuate more than normal.
Parametric determination may include selecting quantities such as the frequency, amplitude, and phase components of the low frequency component of an AMPWM signal based on such comparisons in an attempt to achieve normal EEG presentation. By using pulse width modulation for the purpose of varying the duty cycle of the electrical signal of relatively high frequency, the time-averaged current deliverable by that signal can be controlled. Therefore, further to this embodiment, the pulse width duty cycle of the high frequency component of an AMPWM signal is selected based on such comparisons to affect the time averaged current delivered by the AMPWM signal in an attempt to achieve normal EEG presentation.
In one embodiment of this method of parametric determination, the frequencies for the low frequency signal components of the electrical signal, such as an AMPWM signal, are selected to modulate either excessive or diminished EEG activity, as determined by the aforementioned comparative analysis. In other words, determining parametric values may include selecting frequencies for low frequency signal components of an electrical tissue stimulation signal to modulate either excessive or diminished EEG activity, as determined by the comparative analysis. In this embodiment, if excessively high frequency EEG activity were found in a region of the brain, a lower frequency may be used as the low frequency component of the electrical signal for stimulating that region of the brain. In other words, selecting frequencies for low frequency signal components may include selecting a lower frequency as the low frequency component of the electrical signal for stimulating a region of the brain where excessively high frequency EEG activity is found, with a “lower frequency” being defined as between 1 and 20 hertz lower than the value of the identified excessively high EEG frequency. In practice, a progressively lower frequency might be used in therapeutic activity until the excessive EEG activity in a region of the brain reduces to a more normal level. The EEG of the brain may be continually monitored during therapeutic activity, providing an indication of the effectiveness of the therapeutic activity.
Electrical stimulation signals such as AMPWM signals may be directed through desired tissues or tissue regions by introducing such signals so as to cause current to flow through the desired tissues or tissue regions. This may be accomplished by first placing any number of stimulating leads 121 in proximity to the tissues or tissue regions to be stimulated, and further placing any number of ground leads 120 in another proximity to the tissues or tissue regions to be stimulated such that a vector path extends between stimulating leads and ground leads and passes through the particular tissues meant to receive electrical stimulation. In other words, at least one stimulating lead 121 and one ground lead 20 are placed in proximity to a tissue region to be stimulated such that a vector path extending between the stimulating lead and the ground lead passes through the tissue region to be stimulated. An electrical stimulation signal is then introduced through the at least one stimulating lead such that current is caused to flow along the vector path through the tissue region between the stimulating lead and the ground lead.
Thus, any number of stimulating leads may, for example, be placed in proximity to the brain tissues where abnormal EEG activity has been determined to exist. Further, any appropriate number of ground leads may be placed in further proximity to the brain tissues so as to create a vector that extends between stimulating leads and ground leads and that passes through the brain tissue to be stimulated. In this arrangement, application of an electrical signal for stimulating brain tissues will cause a current flow through such brain tissue, in an approximate vector direction between stimulating leads and ground leads.
Parametric determination for the purpose of stimulating a brain may include a plurality of desirable stimulation frequencies being determined by EEG analysis as detailed above. As previously taught, a form of an AMPWM signal may be generated by, for example, creating a low frequency component waveform featuring multiple frequency components, as determined by inverse Fourier Transform methods. The plurality of desirable stimulation frequencies may be used to determine a single waveform of multiple low frequency components by inverse Fourier Transform computation, and may be used for creating an AMPWM signal and may further be used for stimulating a brain, as previously described. In other words, the application of inverse Fourier Transform methods may include using inverse Fourier Transform computation to determine from the plurality of desirable stimulation frequencies a single waveform of multiple low frequency components, and the application of an electrical stimulation signal may include using the single waveform to create and use an AMPWM signal to stimulate brain tissue
Parametric determination for the purpose of stimulating a brain may alternatively include acquiring EEG data from brain tissue during therapeutic tissue stimulation signal application activity and analyzing the data at a time generally concurrent to the stimulation signal being applied. In other words, obtaining biopotential voltage data may include acquiring EEG data of brain tissue during therapeutic stimulation signal application activity, and determining parametric values may include analyzing the EEG data as the stimulation signal is being applied. Analysis of the EEG may include the use of one or more of those methods previously described for EEG acquired from brain tissue prior to stimulating the brain, for example. Based on this analysis, comparisons may be made between the acquired EEG presentation and a desired EEG in a normal presentation. In this alternate embodiment, quantities such as the frequency, amplitude and phase components of the low frequency component of an AMPWM signal may be altered based on these comparisons in an attempt to achieve a normal EEG presentation. In this implementation, the pulse width duty cycle of the high frequency component of an AMPWM signal may be altered based on the comparisons to affect the time averaged current delivered by the AMPWM signal in an attempt to achieve normal EEG presentation.
Parametric determination for the purpose of stimulating a brain may alternatively include substituting in the disclosed methods any number of sensory inputs other than EEG data to enable quantifying of the condition of tissues or any other functional state of a subject. In other words, determining parametric values may include obtaining sensory inputs quantifying the functional state of a subject, and then determining parametric values for the purpose of stimulating brain tissue in response to the sensory inputs. Such sensory inputs may include, but are not limited to, tissue impedance, temperature, oxygen saturation, EMG activity, electrocardiographic activity, biochemical levels, and/or measures involving respiration patterns.
Further to the methods disclosed for deriving quantities such as the frequency, phase, pulse width duty cycle, and amplitude of electrical signals for stimulating tissues, such as an AMPWM signal, a number of methods may be used for controlling the application time of the signals.
For example, the amount of time that an electrical signal for stimulating tissues is to be applied to a subject may be predetermined and set programmatically based on empirical evidence gained from clinical experience, and then controlled by software to start and stop the application of the signal.
Alternatively, software may be provided to start an electrical signal for stimulating tissues and to stop the signal application automatically, as certain measures in tissue electrical properties are achieved. In other words, controlling signal application time may include starting and then automatically stopping an electrical tissue stimulation signal in response to the achievement of certain desired measures of tissue electrical properties. With reference to the method of stimulating brain tissues taught herein, the EEG of the brain may be further acquired during the therapeutic activity and analyzed at a time generally concurrent with the stimulation signal being applied. The electrical signal application may be stopped when any number of predetermined EEG properties is achieved. In other words, controlling signal application time may include acquiring EEG data from brain tissue during therapeutic electrical tissue stimulation activity, analyzing the acquired EEG data as the stimulation signal is being applied, and stopping the electrical signal application when one or more predetermined EEG properties are achieved. This alternative method may include termination of signal application in response to one or more other measures of sensory input including, but not limited to, tissue impedance, temperature, oxygen saturation, EMG activity, electrocardiographic activity, biochemical levels, and measures involving respiration patterns.
Alternatively, automation of signal termination based on sensory input may be combined with predetermination of a time for signal application, such that the electrical signal will not exceed a predetermined time if desired electrical properties of the tissue are not achieved.
Generally, each of the methods disclosed can be applied to tissues that are not brain tissues, such as tissues including, but not limited to, muscles, bones, tendons, ligaments, cartilage, fascia, dermis (i.e., layers of skin), and/or internal organs. Parametric determination generally relies on first taking measures of tissue electrical properties prior to application of any electrical signal for the purposes of stimulating the tissues. Upon collection of tissue electrical property data, an analysis for the purpose of making statistical comparisons between the findings and measures known to represent normal tissue electrical properties in a healthy normal population of living beings, including human beings, may be performed. In other words, a method is provided for electrically stimulating tissue in which parametric values of an electrical tissue stimulation signal may be determined by first taking measures of electrical properties of a region of tissue to be stimulated, making statistical comparisons between the measures and measures known to represent normal tissue electrical properties in a healthy normal population of living beings, determining parametric values of an electrical tissue stimulation signal in response to the comparisons, and then generating and applying to the region of tissue an electrical stimulation signal having the determined parametric values.
The method of parametric determination may be completed as quantities such as the frequency, amplitude and phase components of the low frequency component of an AMPWM signal are selected based on such comparisons, in an attempt to achieve normal tissue electrical property presentation. By using pulse width modulation for the purpose of varying the duty cycle of a high frequency component of an AMPWM signal, the time-averaged current deliverable by that signal can be controlled. Thus, the pulse width duty cycle of the high frequency component of an AMPWM signal may be selected, based on these comparisons, to affect the time averaged current delivered by the AMPWM signal, in an attempt to achieve normal tissue electrical property presentation.
As described further above, in directing the electrical signals for the purpose of stimulating tissues, the electrical signal may be introduced so as to cause current to flow through such tissues, involving first placement of any number of stimulating leads 121 in proximity to the tissues, and further by placing any suitable number of ground leads 120 in another proximity to the tissues. In one placement pattern, a vector direction between stimulating leads 121 and ground leads 120 passes through the particular tissues meant to receive electrical stimulation.
Thus, stimulation of tissues other than a brain may be accomplished by placing any appropriate number of stimulating leads 121 in proximity to the tissues. Correspondingly, any suitable number of ground leads 120 is placed in further proximity to the tissues, so as to create a vector direction between stimulating leads 121 and ground leads 120 that passes through the particular tissue to be stimulated. In this arrangement, application of an electrical signal for stimulating tissues will cause a current flow through the tissues, in an approximate vector orientation between electrodes 122 of stimulating leads 121 and ground leads 120.
As a further alternative, parametric determination for the purpose of using electrical signals for stimulating tissues, including brain tissues and tissues that are not brain tissues, a measure of biochemicals, particularly neurochemicals and neurotransmitters, may first be taken from tissues and/or fluids relevant to the tissues to be stimulated. The measures may then be analyzed by, for example, making comparisons between the findings of the measure of biochemicals and similar measures known to represent normal levels of the biochemicals in a healthy normal population of living beings, including human beings. Such comparisons may be done for the purpose of quantifying differences that indicate either excessive, that is, greater amounts of certain biochemicals than normal, or diminished, that is, lower amounts of certain biochemicals than normal. In other words, a method is provided that may include determining parametric values of an electrical tissue stimulation signal by taking measures of biochemicals from tissues and/or fluids relevant to the tissues to be stimulated, analyzing the measures, and determining parametric values of an electrical tissue stimulation signal in accordance with the analysis of the measures. An electrical stimulation signal may then be generated and applied to the region. The applied signal may have the determined parametric values and may be configured to reduce tissue impedance and increase depth of signal penetration.
Parametric determination may further include determination of molecular resonant frequencies associated with biochemicals determined to be excessive or diminished in a subject. An electrical signal for stimulating tissues may be applied for the purpose of affecting abnormal biochemical levels. In other words, determining parametric values in response to the comparisons may include determining electrical signal parameters that will tend to normalize abnormal biochemical levels when such a signal is generated and applied to the subject.
Parametric determination may include selecting quantities such as the frequency, amplitude, and/or phase components of the low frequency component of an AMPWM signal, based on the molecular resonant frequencies associated with biochemicals to be used, in an attempt to achieve normal biochemical presentation. The pulse width duty cycle of the high frequency component of an AMPWM signal may be selected based on such comparisons, to affect time averaged current delivered by the AMPWM signal, in an attempt to achieve normal biochemical presentation. The involved biochemical levels may be continually or periodically monitored during therapeutic activity, providing an indication of the effectiveness of the therapeutic activity.
Parametric determination may rely on making comparisons between the findings of abnormal biochemical levels in a subject, and the determination of the frequencies for the low frequency signal component of an electrical signal, such as an AMPWM signal, may be made based on empirical findings of frequencies that are known to be relevant to stimulating the biochemicals, the frequencies being those potentially different than resonant frequencies associated with the biochemicals. For example, the frequencies for the low frequency signal component of an electrical signal, such as an AMPWM signal, may be selected to modulate diminished levels of the neurotransmitter serotonin, the diminished levels being common to such conditions as depression and chronic pain, as determined by the aforementioned comparative analysis. In various examples of published literature, production of serotonin has been shown to be increased by stimuli at a frequency of between about one and 60 hertz, more preferably at about 10 hertz. In accordance with the method taught herein, the low frequency component of an AMPWM signal may therefore be selected to be between about one and 60 hertz, more preferably about 10 hertz, in an attempt to increase serotonin production.
A number of methods are provided for deriving, setting and altering quantities or parameters such as the frequency, phase, pulse width duty cycle, and/or amplitude of electrical signals for stimulating tissues, such as an AMPWM signal, wherein information may be transmitted between an electrical stimulation apparatus as taught herein and a remote location.
According to one such method, measures of electrical parameters used to quantify the condition of tissues or any other appropriate functional state of a subject may first be obtained as described above. Such electrical parameters may include, but are not limited to, tissue impedance, temperature, oxygen saturation, EEG activity, EMG activity, electrocardiographic activity, biochemical levels, and/or measures involving respiration patterns. These measures may be transmitted to a remote location, via a network, such as the Internet or via another communication medium.
Analysis and comparisons, similar to those described above, may be performed at the remote location for the purpose of determining quantities such as the frequency, phase, pulse width duty cycle, amplitude, start time, and stop time parameters of electrical signals for stimulating tissues, such as an AMPWM signal. The parameters for an electrical signal for stimulating tissues may then be transmitted from the remote location, via a network, such as the Internet or via other communication medium, to an electrical stimulation apparatus as taught herein, and used in the therapeutic application of the electrical signal on a subject. In other words, a method is provided for electrically stimulating tissue that may include the determination of parametric values of an electrical tissue stimulation signal by taking measures of electrical properties of a subject, then transmitting the measures to a remote location via a network such as the Internet, analyzing the measures at the remote location by, for example, making statistical comparisons between the measures and measures known to represent normal tissue electrical properties in a healthy normal population of living beings, remotely determining parametric values of an electrical tissue stimulation signal in response to the analysis, transmitting the parametric values from the remote location via a network such as the Internet to an electrical stimulation apparatus, and causing the electrical stimulation apparatus to generate and apply to a region of the subject's tissue an electrical stimulation signal, e.g., a signal, such as an AMPWM signal, configured to reduce tissue impedance and increase depth of signal penetration, and having the remotely determined parametric values.
Alternatively, according to this method, measures of electrical parameters that are used to quantify the condition of tissues or other appropriate functional state of a subject may be acquired during the therapeutic activity at a time generally concurrent to the application of the stimulation signal. Such electrical parameters may include, but are not limited to, tissue impedance, temperature, oxygen saturation, EEG activity, EMG activity, electrocardiographic activity, biochemical levels, and/or measures involving respiration patterns. These measures may be transmitted to a remote location, via a network, such as the Internet or via other communication medium.
Analysis and comparisons as described herein may be performed at the remote location for the purpose of altering quantities such as the frequency, phase, pulse width duty cycle, amplitude, start time, and/or stop time parameters of electrical signals for stimulating tissues, such as an AMPWM signal. The determined parameters for altering an electrical signal for stimulating tissues may be transmitted from a remote location, via a network, such as the Internet or via other communication medium, to an electrical stimulation apparatus as taught herein, and used in the further therapeutic application of the altered electrical signal on a subject. In other words, taking measures may include acquiring measures of electrical parameters from a subject as a stimulation signal is being applied to the subject, and remotely determining includes altering quantities such as the frequency, phase, pulse width duty cycle, amplitude, start time, and/or stop time parameters of electrical tissue stimulation signals in response to such measures taken as a stimulation signal is being applied.
The analysis and comparisons as taught herein may be performed at the remote location for the purpose of determining changes in the electrical parameters over time, in accordance with the application of therapeutic activities. Parameter changes over time may be transmitted from a remote location, via a network, such as the Internet, or via other communication medium, to a subject or a person of sufficient competence such as a physician, and used to provide an indication of changes in the electrical parameters over time, in accordance with the application of therapeutic activities.
In addition, symptom data may be acquired from a subject and transmitted via a network, such as the Internet, or via another communication medium, from a subject or a person of sufficient competence, such as a physician, to the remote location for the purpose of tracking changes in symptoms associated with a condition of the subject over time, in accordance with the application of therapeutic activities. In other words, symptom data may be acquired from a subject, transmitted to the remote location via a communication medium such as the Internet, and recorded at the remote location. Changes in the subject's symptoms may be tracked by repeating the acquiring, transmitting, and recording of data on the subject's symptoms. This symptom data may be compared to measures of electrical parameters acquired, and transmitted to a remote location either (a) periodically during the therapeutic activity, or (b) at a time generally concurrent with the stimulation signal being applied, as taught herein. A comparison of symptom data and changes in electrical parameters may be made and transmitted from a remote location, via a network, such as the Internet, or via other communication medium, to a subject or a person of sufficient competence such as a physician, and used for the purpose of providing indication of changes in the symptoms over time in accordance with the application of therapeutic activities.
In accordance with the methods taught herein for providing feedback and information about changes in electrical parameters and/or symptoms, such feedback may include, but is not limited to, methods involving statistics or graphical representations of such changes, any method of visually illustrating the changes, and any method of audibly illustrating the changes.
A number of methods are provided for treatment of various conditions using electrical signals for stimulating tissues, such as an AMPWM signal.
As shown in step S2, the measured biophysical activity may be compared to normal biophysical activity for that portion of the body. The analysis of biophysical activity may involve either biophysical values from individual sites or multiple sites. The analysis may include statistical analyses of biophysical voltages, their frequency components, and/or their phase components. In addition, the statistical analysis may include measures of variance, correlation, and/or coherence. This step, either alone or in connection with steps S3 and S4, as described further below, may be performed either at the location in which the measurements are taken, or at a remote location to which the measurements have been transmitted.
As shown in step S3, the site to which electrical stimulation will be applied may be determined, based on, for example, regions where the measured biophysical levels differ from the normal, desired biophysical activity. The differences in the biophysical levels are quantified and treatment sites may include regions where the frequency or amplitude components of the subject's biophysical levels exhibit greater values than normal, lower values than normal, and/or values that fluctuate more than normal. The site to which the electrical signal is to be applied may include muscles, bones, tendons, ligaments, cartilage, fascia, dermis, and/or internal organs.
As shown in step S4, electrical parameters including, but not limited to, the frequency, phase, pulse width duty cycle, and amplitude may be determined for the electrical signal to be applied to the subject, based on, for example, the analysis performed in step S2, to attempt to bring the subject's biophysical values for the determined site to more normal, desired values.
As shown in step S5, at least one stimulating lead may be placed in proximity to the determined site. As shown in step S6, at least one ground lead may be placed so as to create a vector direction between the stimulating lead and the ground lead that passes through the site to be treated. In this manner, the path of the electrical stimulation will pass through the site to be treated. Any suitable number of stimulation and ground leads may be used.
As shown in step S7, an electrical signal may be applied through the leads, the electrical signal having the determined parameters such as, but not limited to, frequency, phase, pulse width duty cycle, and/or amplitude. The electrical signal may be, for example, an AMPWM signal, general examples of which are shown in
As shown in step S8, information may be acquired from a sensory input generally concurrent with the application of the electrical signal, to quantify the condition of either the site being treated with the electrical signal or the functional state of the subject being treated. Such sensory inputs may include measures of biophysical activity, including but not limited to EEG, EMG, tissue impedance, temperature, oxygen saturation, electrocardiographic activity, biochemical levels, and/or respiratory patterns. This monitoring of sensory inputs may occur as a continual process throughout the therapeutic application of the electrical signal. Biophysical activity of the subject may be sampled at times of minimal electrical stimulation signal amplitude, such as at zero amplitude.
As shown in step S9, at least one characteristic parameter of the electrical signal may be altered based on a comparison of the information acquired from the sensory input and a desired value in a normal subject. Electrical signal parameters such as, but not limited to, the frequency, phase, pulse width duty cycle, and/or amplitude of the electrical signal may be altered. The application of the electrical signal may be stopped based on certain measures in tissue electrical properties being achieved. In addition, the particular leads used to apply the electrical stimulation may be varied. The comparison/analysis of the information acquired in step S8 may occur at the location at which the measurements are taken or at a remote location to which the sensory input information has been transmitted.
A central nervous system condition of a subject may be treated by stimulating tissues in close proximity to the vagus nerve using an AMPWM signal. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed at the posterior base of the neck of the subject near the first, second, or third cervical vertebrae. An electrode 122 of a ground lead 20 may be adapted to be placed on tissue in a position creating a vector between electrodes 122 that passes near the vagus nerve.
A brain of a subject may be treated by stimulating tissues in close proximity to the vagus nerve using an AMPWM signal. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed at the posterior base of the neck of the subject near the first, second, or third cervical vertebrae. An electrode 122 of a ground lead 20 is adapted to be further placed on tissue, creating a vector between electrodes 122 that passes near the vagus nerve.
Alternatively, a brain of a subject may be treated using an AMPWM signal. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of the subject near an area of the brain identified as having a dysfunction, such as, but not limited to, identification by EEG analysis. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near the area of the brain identified as having a dysfunction, creating a vector between electrodes 122 that passes through the area of the brain identified as having the dysfunction.
Tissues containing an injury may also be treated using an electrical tissue stimulation signal that reduces tissue impedance and increases depth of signal penetration, such as an AMPWM signal. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of the subject near the location of the injury. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near the location of the injury, creating a vector between electrodes 122 that passes through the injury.
Tissues containing an injury involving a bone may also be treated using a signal, such as an AMPWM signal, configured to reduce tissue impedance and increase signal penetration depth. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of a subject near the bone injury. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near the bone injury, creating a vector between electrodes 122 that passes through the bone injury.
Tissues containing an injury involving a muscle may also be treated using a signal, such as an AMPWM signal, configured to reduce tissue impedance and increase signal penetration depth. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of the subject near the muscle injury. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near a muscle injury, creating a vector between electrodes 122 that passes through the muscle injury.
Muscle tissues containing a painful condition for a subject, such as a myofascial trigger point, may also be treated using a signal, such as an AMPWM signal, configured to reduce tissue impedance and increase signal penetration depth. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of the subject near the muscle containing a painful condition, such as a myofascial trigger point. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near the muscle containing a painful condition, creating a vector between electrodes 122 that passes through the muscle containing a painful condition; i.e., through the myofascial trigger point.
A myofascial trigger point may also be treated using a signal, such as an AMPWM signal, configured to reduce tissue impedance and increase signal penetration depth. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of a subject near a myofascial trigger point. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near a myofascial trigger point, creating a vector between electrodes 122 that passes through the myofascial trigger point.
Myofascial pain may also be treated using an electrical tissue stimulation signal that reduces tissue impedance and increases depth of signal penetration, such as an AMPWM signal. In one arrangement of lead placement, an electrode 122 of any stimulating lead 121 may be adapted to be placed on tissue of a subject near the location of myofascial pain. An electrode 122 of a ground lead 20 may be adapted to be further placed on tissue near the location of myofascial pain, creating a vector between electrodes 122 that passes through the tissue involved in myofascial pain.
Conditions associated with central nervous system dysfunction may be treated with an electrical tissue stimulation signal, such as an AMPWM signal, which reduces tissue impedance and increases depth of signal penetration. Such conditions may include but are not limited to fibromyalgia syndrome, chronic pain, traumatic brain injury, affective disorders, such as attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD), chronic fatigue, sleep disorders, obsessive compulsive disorder, Tourette Syndrome, depression, anxiety, and addiction.
Conditions associated with abnormal levels of biochemicals including, but not limited to neurotransmitters and/or neurochemicals in tissues, may also be treated with an electrical signal of this type. Such conditions may include, but are not limited to, fibromyalgia syndrome, chronic fatigue, obesity, chronic pain, muscle pain, myofascial pain, myofascial trigger points, and psychological conditions, such as depression.
An electrical tissue stimulation signal of this type may also be used to enhance a body's own healing mechanisms in treating such conditions as broken bones, injured tissues, post-surgical wounds, cuts, muscle pain associated with strains, and spasms.
Such a signal may also be used to stimulate tissue in a manner that reduces fatigue, increases alertness, and/or increases mental clarity. In other words, a body's function can be improved by applying an electrical tissue stimulation signal to a subject, where the signal is configured and applied in such a way as to produce one or more beneficial effects such as reducing fatigue, increasing alertness, and increasing mental clarity.
An electrical tissue stimulation signal of a type describe above may also be used to enhance performance associated with, but not limited to, sporting activities, academic activities, and similar competitive endeavors. Such a signal may also be used for tissue stimulation for purposes of advantageously enhancing the function of organs. In one illustrative method, an AMPWM signal may be used to stimulate pancreatic tissues so as to enhance production of insulin, thereby affecting conditions such as diabetes.
For the various methods and apparatus taught herein, treatment times may range between about 1 second and about 60 minutes, with low frequency components of an AMPWM signal ranging between about 1 hertz and about 200 hertz, and high frequency components of an AMPWM signal ranging between about 100 hertz and about 1,000,000 hertz. The duty cycle of an AMPWM signal may range between about 1 percent and about 99 percent, and assessment periods used for the purpose of analyzing acquired biopotential voltages and selectively switching the use of leads may range between about 1 second and about 60 seconds.
Symptoms may also be alleviated; conditions treated and brain activities involving central sensitivity in a subject altered, by applying brain stimulation to the subject. More specifically, one or more conditions in a subject that involve central sensitivity, one or more symptoms of such conditions, or one or more brain activities associated with central sensitivity, may thus be alleviated. The alleviation of the conditions, symptoms or brain activities may be accomplished by administering a stimulation signal to tissues such that the stimulation signal is transmitted to one or more regions of the subject's brain, which are at least one part of a pathway of central sensitivity. These regions of the subject's brain can include those regions that possess any function or physiological state that is at least one part of a pathway of central sensitivity. These regions of the subject's brain can also include regions of the brain that do not possess any function or physiological state that is at least one part of a pathway of central sensitivity, but are otherwise functionally interrelated with those regions that do possess such a function or physiological state. One of skill in the neurological arts would recognize which regions of the brain are interrelated with other regions of the brain.
Where the method is directed toward alleviating symptoms associated with central sensitivity in a subject, or treating a condition associated with central sensitivity in a subject, the method may include selecting a subject suffering from one or more symptoms or conditions associated with central sensitivity, determining the presence of central sensitivity in the subject, identifying at least one target region of the subject's brain as being related to the central sensitivity, and stimulating the at least one target region of the brain of the subject. The method may further include administering one or more pharmaceutical agents to the subject. The symptoms associated with central sensitivity that a selected subject may be suffering from may include any one or more of the symptoms and similar indications that are known in the art to be associated with central sensitivity. The conditions associated with central sensitivity that a selected subject may be suffering from may include any one or more of the conditions known in the art to be associated with central sensitivity.
Where the method is directed toward altering brain activity associated with central sensitivity in a subject, the method may include selecting a subject exhibiting, in one or more regions of the subject's brain in response to one or more peripheral stimuli, one or more brain activities associated with central sensitivity; and stimulating a target region of the brain of the subject. The method may further include determining the presence of brain activity associated with central sensitivity in the subject, identifying at least one target region of the subject's brain as being involved in the brain activity associated with central sensitivity, and administering one or more pharmaceutical agents to the subject. The exhibited brain activity associated with central sensitivity may be any one or more of the brain activities known in the art to be associated with central sensitivity.
The stimulation of a target region of the brain can be accomplished in either an invasive or a noninvasive manner, whether for the purpose of alleviating symptoms, treating a condition, or altering brain activity associated with central sensitivity. Such stimulation may include at least one administration of electrical stimulation to the target region of the brain of the subject and may include at least one administration of magnetic stimulation to a target region of the brain of the subject. Stimulation may be administered in a noninvasive manner in which stimulation is applied to a target region of the brain from outside the subject and transmitted through intervening tissues.
Electrical stimulation may include administration of a stimulating signal that is configured to minimize outer tissue impedance, such as an AMPWM signal, to provide increased conduction of the stimulating signal through such tissues. The administration of an AMPWM signal may be accomplished by placing noninvasive cutaneous electrodes in an arrangement that allows for successful delivery of the AMPWM stimulating signal to a target region of the brain of the subject. This may be done using an apparatus configured to generate and deliver an AMPWM signal to the cutaneous electrodes.
To determine the presence of central sensitivity in a subject, or the presence of brain activity associated with central sensitivity in a subject, or to identify at least one target region of the subject's brain, one skilled in the art of medical assessment may administer and interpret one or more assessments designed to detect central sensitivity, or indications of central sensitivity such as abnormally heightened sensitivity to one or more peripheral stimuli. Such assessments may include any one or more known neuroimaging tests. Such assessments may also be used for detecting the presence and identifying the location of one or more abnormal brain functions through interpretation.
The administration of a pharmaceutical may include administering at least one pain alleviating pharmaceutical agent, and/or at least one central sensitivity alleviating or treatment agent, and/or at least one central sensitivity symptom alleviating or treatment agent. The administration of a pharmaceutical may further include administering at least one pharmaceutical agent formulated to treat or alleviate symptoms of a condition associated with central sensitivity. Further, the pharmaceutical administering step is preferably timed such that the one or more pharmaceutical agents are present in the subject during at least a portion of a time during which the stimulating step is executed.
The invention is not limited in any way to the embodiments described herein. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the method of the invention. The description is intended only to make apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
This application is a continuation application of U.S. patent application Ser. No. 13/212,642, filed Aug. 18, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 12/187,375, filed Aug. 6, 2008, now U.S. Pat. No. 8,494,625 issued on Jul. 23, 2013, claiming the benefit of priority from provisional patent application Ser. No. 61/032,241 filed Feb. 28, 2008, 61/024,641 filed on Jan. 30, 2008, 61/014,917 filed Dec. 19, 2007, and 60/963,486 filed Aug. 6, 2007, and which is also a continuation in part of U.S. patent application Ser. No. 11/490,255, filed Jul. 21, 2006, now U.S. Pat. No. 7,715,910 issued on May 11, 2010, which is a continuation application of U.S. patent application Ser. No. 10/357,503, filed on Feb. 4, 2003, claiming the benefit of U.S. provisional patent application Ser. No. 60/353,234, filed on Feb. 4, 2002.
| Number | Date | Country | |
|---|---|---|---|
| 60353234 | Feb 2002 | US | |
| 61024641 | Jan 2008 | US | |
| 61014917 | Dec 2007 | US | |
| 60963486 | Aug 2007 | US | |
| 61032241 | Feb 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13212642 | Aug 2011 | US |
| Child | 15082798 | US | |
| Parent | 10357503 | Feb 2003 | US |
| Child | 11490255 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12187375 | Aug 2008 | US |
| Child | 13212642 | US | |
| Parent | 11490255 | Jul 2006 | US |
| Child | 12187375 | US |
