Patent Application
20060047316
This invention is in the field of medical devices for the treatment of migraine headaches.
Migraine headaches occur in approximately 12% of the world population. Therefore, in the United States in the year 2004 there are approximately 30 million people who suffer from this affliction. Although medicines have been created that significantly diminish the suffering of migraine patients, these medicines often have highly undesirable side effects and many patients do not obtain satisfactory relief from the severe headache pain, nausea and other discomforts associated with migraine. Furthermore, migraine headaches are typically treated after they have become painful, i.e., the treatment is often ineffective in preventing the onset of the migraine headache. Other than some drugs that are efficacious for some patients, there is currently no known treatment for migraine headaches that can be applied after a patient detects an aura of that headache to prevent the occurrence of pain and other undesirable manifestations of that migraine headache. A non-invasive, non-drug method for preventing the occurrence of migraine headaches would be a remarkable boon for those millions of people all over the world who suffer from these painful experiences.
In 1985, A. T. Barker, et al (Lancet, 1985, pp. 1105-1107) described the use of a coil placed over the scalp which produced a high intensity, time varying, magnetic field. This magnetic field produces an electric current in the cortex of the human brain which can in turn produce certain effects on brain neurons. This type of system has been given the name Transcranial Magnetic Stimulation (TMS). If repetitive magnetic pulses are applied in this manner, it has been given the name rTMS.
In the journal Neurology (Apr. 11, 2000, pp. 1529-1531) it has been reported by B. Boroojerdi, et al that rTMS at a rate of one pulse per second can create a reduction of the excitability of the neurons of the human visual cortex. However, that article did not indicate that TMS or rTMS can be used for the preventing the occurrence of migraine headaches or diminishing the intensity or duration of a migraine headache.
In U.S. Pat. No. 6,402,678, Robert E. Fischell et al describe means and methods for the treatment of migraine headaches using a portable device that is placed onto the patient's head. This device is used to create a magnetic pulse that acts upon the neurons of the brain and can eliminate both the aura of a migraine headache and a migraine headache after it has started. However, since the entire device is placed onto the patient's head, it is quite heavy and somewhat awkward for the patient's use. Furthermore, since the triggering controls are also located on the head mounted device, their operation is also somewhat awkward.
This present invention teaches means and methods for the treatment of migraine headaches for those patients who experience a distinct aura before the actual occurrence of the symptoms of the migraine headache and also for those patients whose migraine headache has already started. It is estimated that approximately 40% of all migraine patients have a distinct aura that is a precursor of a migraine headache. Approximately half of those patients have a visual aura that typically begins as a small pattern of scintillating colored lights that have the appearance of wiggling worms. Over a time period of between 20 and 30 minutes, the pattern enlarges until it occupies nearly the entire visual field. During this time period, the patient might also completely lose all or part of his visual field. At the end of this visual aura, most migraine patients have a severe headache that is often accompanied by other symptoms such as nausea, vomiting and other unpleasant feelings. Many migraine patients who don't have a visual aura have some other precursor of a migraine that can be perceived by themselves or others from minutes to hours before the actual start of the headache. By treatment with a high intensity, short duration magnetic pulse (or pulses) when any precursor of a migraine headache occurs, some migraine headaches can be reduced as to either or both intensity and duration or completely eliminated.
The visual aura of a migraine headache is a result of the spatial progression of a band of brain cells that are excited in that band across one half of the brain's occipital lobe. This band moves in an anterior direction at the rate of approximately 2-5 mm per minute. It is this excited band of neurons of the brain that produces the scintillating colored lights that are perceived by the patient as a visual aura that is a precursor of a migraine headache. Behind this leading band of excited neurons, a spreading region of neurons with depressed electrical excitability occurs. This phenomenon is known as “the spreading depression of Leao”.
Recent tests with human subjects have shown that the advancement of the band of excited neurons can be eliminated before the aura has completed its 20 to 30 minute time duration period, and by that means, the migraine headache never occurs. This is accomplished by applying a high intensity, short duration magnetic pulse onto the neurons of the brain which causes mostly depolarization and some polarization of these neurons, which in turn results in elimination of the visual aura and prevention of the migraine headache.
Although the portable magnetic pulse system as described herein is excellent for the treatment of an aura that frequently precedes a migraine headache, the application of a high intensity, short duration magnetic pulse can also be used for the treatment of an ongoing migraine headache. Although some migraine headaches can be treated with a single magnetic pulse, it is envisioned that some auras and some ongoing migraine headaches can best be treated by the application of a multiplicity of magnetic pulses.
One aspect of the invention that is disclosed herein is a non-invasive, externally applied magnetic pulse system that consists of two major parts; a table unit that would typically be placed on a table and a head unit that is designed to apply the magnetic pulse to the neurons of the brain. For the treatment of aura, the head unit is designed to be placed on or near the patient's head in the region of the brain where the aura originates (e.g., the occipital lobe) as soon as possible after the patient becomes aware of a visual (or any other type) aura that is the precursor of their migraine headache. For patients whose aura originates from a region of the cerebral cortex that is not the occipital lobe, the magnetic pulse can be applied to that region of the brain. By the use of a high intensity, short duration magnetic pulse, a sufficiently high electrical current is created at the location of the advancing band of excited neurons so as to depolarize many of those neurons thereby terminating the aura before it is able to progress into a migraine headache. Mostly depolarization and some polarization of neurons can also be used to treat an ongoing migraine headache. This is because depolarized neurons become refractory after TMS is applied. This is analogous to cutting down or burning the trees in front of a forest fire in order to prevent the spread of that forest fire.
A single high intensity, short duration, TMS magnetic pulse can be used to reduce cerebral cortex excitability thereby breaking up the advancing band of excited neurons that is the cause of the visible aura of a migraine headache. Since an aura has a time duration that is typically at least 20 minutes, the patient has a sufficient time period for placing the head unit in the appropriate position for it to be effective in depolarizing the advancing band of excited brain neurons. If there is an ongoing headache, the patient can place the head unit onto his or her head as soon as possible. For either the treatment of any type of aura or for an ongoing headache, the magnetic pulse system can be used to apply a multiplicity of pulses if the first treatment with a single pulse does not eliminate or significantly reduce the headache.
It should also be noted that stimulation of the scalp or trigeminal nerve might also have an effect in preventing or decreasing the severity or time duration of a migraine headache for at least some patients. Scalp or trigeminal nerve stimulation may act as a conditioning response that becomes associated with the migraine process. Furthermore, it is believed that single or multiple TMS pulses can be used for the treatment of facial pain including trigeminal neuralgia. For this application, the high intensity, short duration magnetic pulse (or pulses) can be applied at the site of the pain, or onto the trigeminal nerve or onto the patient's brain.
Since the band of excited neurons that create a visual aura moves from the back of the head in an anterior direction, and since either the left or right half of the occipital lobe might be involved, the head unit would optimally be placed along the posterior-anterior centerline at the top of the head. If it is known that a particular patient has the spreading depression on either the right or the left half of the occipital lobe, then the head unit might be placed only on that region where the spreading depression occurs. If the aura originates from a part of the cerebral cortex that is not the occipital lobe, then the magnetic pulse can be appropriately placed to depolarize neurons in that location. It is expected that the patient can be trained to recognize the symptoms from a particular area of the brain so that the head unit can be placed in an optimum location to prevent the occurrence of a migraine if it is precede by an aura, or reduce its intensity and/or duration for an ongoing migraine headache.
A sufficiently intense, short duration magnetic pulse must be created to treat a migraine headache. The intensity of the magnetic field at the surface of the brain should be between 0.1 and 2.0 Tesla. The frequency rate of the magnetic pulses should be between one per second and one per minute. With some patients a single, short duration pulse may be all that is required to stop an advancing band of excited neurons from proceeding to a full-blown migraine headache or to reduce the intensity and/or duration of an ongoing migraine headache. For some patients, at least two high intensity, short duration magnetic pulses may be required. By applying a time varying magnetic field to the neurons of the cerebral cortex (and also the neurons in the scalp and/or the trigeminal nerve), a patient should be able to actually prevent the occurrence of a migraine headache or decrease its intensity and duration after the headache has started. As previously described, the optimum placement for head unit of the magnetic pulse system when there is a visual aura is over the patient's occipital lobe. For other auras, the optimum placement for the head unit will be that place on the patient's head that is in closest proximity to the portion of the patient's brain where that aura originates. For an ongoing headache, the patient can discover by trial and error where the optimum location for applying the magnetic pulse is located. One method that has been reasonably successful is to apply the magnetic pulse to that region of the patient's brain where he is feeling the most pain.
Although the patient is referred to herein by use of the masculine words “his,” “he” or “himself,” it should be understood that the patient can be either a man or a woman.
Thus, an objective of this invention is to prevent the occurrence of a migraine headache by creating a high intensity, short duration magnetic pulse by means of a head unit placed onto the scalp of a patient who has an aura which is a precursor of a migraine headache; the head unit being designed to cause depolarization of at least some of the neurons in the cerebral cortex where the aura originates.
Another object of this invention is to decrease the weight of the portion of the magnetic pulse system that has to be placed onto the head (or neck) by limiting the number of components of the system that are placed into the head unit and by placing as many of the additional components of the system that are required into table unit.
Still another objective of this invention is to reduce the severity and/or duration of an ongoing migraine headache by applying a high intensity, short duration magnetic pulse to a patient's brain or trigeminal nerve by means of a head unit that receives its power from a table unit.
Still another object of the invention is to have at least most if not all of the operating controls for the magnetic pulse system placed on the table unit where they are most easily operated by the patient.
Still another object of the invention is to have the magnetic pulse system obtain its electrical power from either a-c line power, from the cigarette lighter in an automobile or from an internal or external rechargeable or disposable battery.
Still another object of the invention is to place the capacitors needed for providing a high intensity electrical current pulse into the head unit of the magnetic pulse system so that the electrical connecting wire to the table unit can be lightweight and flexible.
Still another object of the invention is the placement of the capacitors needed for providing a high intensity electrical current pulse in the handle of the head unit of the magnetic pulse system so that the capacitors can be located in close proximity to the magnetic coil that requires the high current from the capacitors to generate the high intensity magnetic pulse.
Still another object of the system is to have the magnetic coil of the head unit shaped in the form of a spherical sector so as to maximize the intensity of the magnetic pulse onto the neurons of the brain.
These and other objects and advantages of this invention will become obvious to a person of ordinary skill in this art upon reading the detailed description of this invention including the associated drawings as presented herein.
Once the capacitor discharge occurs, the CHARGE push-button can be pushed again and the patient can apply a second high intensity, short duration magnetic pulse to his head. Any number of additional pulses could be applied by the patient to his head or neck region if he believes that it would decrease the intensity or duration of his migraine headache. It is conceived that the table unit 30 would include a counter that counts the total number of pulses between visits to the patient's doctor so that the use of the magnetic pulse system 10 can be monitored.
The magnetic pulser portion 21 includes a conducting wire coil 23 through which an electrical current pulse is used to create the high intensity, short duration magnetic pulse that is required to abort a migraine headache. To create a magnetic pulser portion 21 with the lowest possible weight, the coil 23 is optimally made from insulated square or rectangular wire that is made from copper or aluminum. In point of fact, the lowest possible weight is obtained by the use of aluminum wire for the coil 23.
Also shown in
As seen in
It should be understood that in order to be useful to a migraine patient, the magnetic pulse system 10 must have several distinct characteristics that are different from currently available systems for TMS or repetitive Transcranial Magnetic Stimulation (rTMS). Specifically, the inventive concept of the present invention includes the fact that the magnetic pulse system 10 is readily portable, has preset operating parameters that are not adjustable by the patient, can be placed on the patient's head by the patient and is turned on and off by the patient. “Readily portable” can be defined as having a weight for the entire magnetic pulse system 10 of less than 10 kg with the head unit having a weight of less than 3 kg. More optimally, the entire system should weigh less than 5 kg and the head unit less than 1.5 kg. One of the well known types of TMS and rTMS equipment is the Cadwell MES-10 unit that is operated by a physician and not by a patient, has operational parameters that are adjustable by the physician as it is being used (i.e., the parameters are not preset), has a magnetic coil that is placed on a patient by an attending physician, and since the entire system weighs 34 kg it is certainly not readily portable so as to be with the patient wherever he might need it. Furthermore, the capacitors of the Cadwell unit are not located in its head unit so that the cable connecting its table unit to its head unit is extremely heavy, stiff and has a large diameter. To be useful for its intended purpose, the magnetic pulse system 10 should have operating parameters that are preset by an attending physician or preset at the factory. These operating parameters can include one or more of the following attributes: the peak intensity of the magnetic field at a distance of 1.0 cm beneath the head unit, the time period of each magnetic pulse; the maximum allowed repetition rate of the magnetic pulses; and the total number of pulses to be delivered when the magnetic pulse system 10 is turned on. Once these parameters are set, the patient would operate the system 10 by placing it on his head and then turning the system on and then off after the treatment for the migraine headache has been terminated. It may be desirable for the patient to turn the system on but a timer could automatically turn the system off after a preset period of time.
Since the aura of a migraine headache might occur at any time, and since the patient may have only 20 minutes to use the magnetic pulse system 10, each patient would want to have a system in relatively close proximity. For example, the patient would want to have the system at home, and/or at work, and/or in his car. The magnetic pulse system 10 would optimally be sufficiently portable to be taken with the patient on a vacation or on a business trip.
It is also envisioned that the magnetic pulse system 10 could include a memory for recording various parameters of the magnetic pulse system including the setting of the magnetic field intensity or how many pulses have been used by the patient. Within a limited range, it is envisioned that the patient could set different levels for the magnetic field intensity in order to determine that level that is most effective in preventing a migraine headache. It is further envisioned that the magnetic pulse system 10 as described herein could be used for the treatment of other disorders such as depression, pain, epilepsy (especially acute and/or febrile seizures), bi-polar disease and other disorders of the nerves or brain such as trigeminal neuralgia and tinnitus. It is also envisioned that the system could be adapted for measuring nerve conduction velocity in various parts of the human body.
Various other modifications, adaptations and alternative designs are of course possible in light of the teachings as presented herein. Therefore it should be understood that, while still remaining within the scope and meaning of the appended claims, this invention could be practiced in a manner other than that which is specifically described herein.
