U.S. patent application number 09/778244 was filed with the patent office on 2001-07-12 for method for inducing electroanesthesia using high frequency, high intensity transcutaneous electrical nerve stimulation.
This patent application is currently assigned to Synaptic Corporation. Invention is credited to Silverstone, Leon M..
Application Number | 20010007949 09/778244 |
Document ID | / |
Family ID | 26894444 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007949 |
Kind Code |
A1 |
Silverstone, Leon M. |
July 12, 2001 |
Method for inducing electroanesthesia using high frequency, high
intensity transcutaneous electrical nerve stimulation
Abstract
A non-invasive method of treating, controlling or preventing
medical, psychiatric or neurological disorders is provided using
transcutaneous electrical stimulation. A plurality of stimulation
frequency parameters are used ranging from a relatively high
frequency, for example about 40,000 Hertz, to a relatively low
frequency, for example about 250 Hertz. The entirety of frequency
parameters may be administered at each of a plurality of
stimulation intensity levels. In particular, stimulating may begin
at a first highest frequency parameter and a first lowest intensity
parameter with the stimulation frequency parameter incrementally
decreasing to the lowest frequency parameter. Then the frequency
parameter is returned to the highest frequency parameter, and the
intensity parameter increased to a next higher intensity parameter,
and again stimulating through the plurality of frequency parameters
from the highest frequency to the lowest frequency. The method
described herein is useful in treating, controlling and/or
preventing various disease states and disorders, and has been found
to be particularly effective in administering nerve block
electroanesthesia.
Inventors: |
Silverstone, Leon M.; (San
Diego, CA) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
606033406
|
Assignee: |
Synaptic Corporation
|
Family ID: |
26894444 |
Appl. No.: |
09/778244 |
Filed: |
February 6, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09778244 |
Feb 6, 2001 |
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09691626 |
Oct 18, 2000 |
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09691626 |
Oct 18, 2000 |
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09199073 |
Nov 23, 1998 |
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6161044 |
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Current U.S.
Class: |
607/45 |
Current CPC
Class: |
A61N 1/36021 20130101;
A61N 1/36025 20130101 |
Class at
Publication: |
607/45 |
International
Class: |
A61N 001/36 |
Claims
What is claimed is:
1. A non-invasive method of inducing nerve blocks by using
electroanesthesia applied via transcutaneous electrical
stimulation, which method comprises affixing a first electrode pair
to the skin of a patient to be treated in the vicinity of the nerve
to be blocked, which electrode pair is associated with a pulse
generator such that stimulation at a desired frequency and
intensity may be provided to the patient through said electrode
pair, affixing a second electrode pair to the skin of a patient
either on the opposite side of the body from the location of the
first electrode pair or bilaterally of the spine at about C5, said
second electrode pair being larger in size than said first
electrode pair and also being associated with the pulse generator,
and thereafter carrying out the following steps of: (a) providing
the patient with a series of intensities at which stimulation may
be carried out; (b) choosing an intensity from said series as high
as the patient can reasonably tolerate; (c) stimulating at a first
high frequency in the range of 60,000 Hz to about 25,000 Hz and at
said chosen intensity; and (d) decreasing the stimulation frequency
at said chosen intensity to a lower frequency over a time period of
at least about 20 minutes by initially lowering the frequency to a
level that is still tolerable to the patient and then continuing to
gradually decrease the frequency thereafter.
2. The method of claim 1 wherein said first high intensity is
between about 55 and about 40 volts.
3. The method of claim 2 wherein the first high frequency parameter
is about 40,000 Hertz and the lowest frequency parameter is not
less than about 250 Hertz.
4. The method of claim 2 wherein said first high intensity is at an
amperage of about 40 milliamps.
5. The method of claim 2 wherein said stimulating employs a
waveform having a fast time rise and a slow decay.
6. The method of claim 2 wherein the first high frequency parameter
is about 40,000 Hertz and the lowest frequency parameter is not
less than about 400 Hertz.
7. The method of claim 1 wherein said second electrode pair is
located bilateral of the spine at C5.
8. The method of claim 1 wherein said decreasing of the stimulation
frequency is performed over a time duration (T) of at least about
20 minutes and comprises the steps of: a) decreasing the
stimulation frequency about 73% of the first high frequency over
the first time period 0.1T; b) then decreasing the stimulation
frequency about another 8% of the first high frequency over the
next time period 0.1T; c) then decreasing the stimulation frequency
about another 5% of the first high frequency over the next time
period 0.1T; d) then decreasing the stimulation frequency about
another 4% of the first high frequency over the next time period
0.1T; and e) then decreasing the stimulation frequency about
another 10% over the remaining time period of 0.6T.
9. The method of claim 8 wherein the first high frequency parameter
is about 40,000 Hertz and the lowest frequency parameter is not
less than about 400 Hertz.
10. The method of claim 9 wherein said first high intensity is
between about 55 and about 40 volts at an amperage of about 40
milliamps.
Description
FIELD OF THE INVENTION
[0001] This application is a continuation-in-part of U.S. Ser. No.
09/691,626, filed Oct. 18, 2000, abandoned, which was a
continuation of U.S. Ser. No. 09/199,073, filed Nov. 23, 1998, now
U.S. Pat. No. 6,161,044, the disclosures of both of which are
expressly incorporated by reference.
[0002] The present invention relates to improved methods for the
non-invasive treatment of various disease conditions using an
improved process of transcutaneous electrical stimulation. In
particular, provided herein are improved methods of non-invasively
treating symptoms of tremor disorders including essential tremors
and tremors associated with Parkinson's Disease; symptoms of
dementia disorders including cortical dementia, such as is found in
Alzheimer's disease and Pick's disease, subcortical dementia, such
as is found in Parkinson's disease, Huntington's chorea and
supranuclear palsy, and multi-infarct dementia; and symptoms of
painful degenerative disorders, such as fibromyalgia and reflex
sympathetic dystrophy by using transcutaneous electrical nerve
stimulation programs of variable intensity and variable frequency.
Also provided are apparatus for performing such methods.
BACKGROUND OF THE INVENTION
[0003] Transcutaneous electrical nerve stimulation (TENS) is a well
known medical treatment used primarily for symptomatic relief and
management of chronic intractable pain and as an adjunctive
treatment in the management of post surgical and post traumatic
acute pain. TENS involves the application of electrical pulses to
the skin of a patient, which pulses are generally of a low
frequency and are intended to affect the nervous system in such a
way as to suppress the sensation of pain that would indicate acute
or chronic injury or otherwise serve as a protective mechanism for
the body. Typically, two electrodes are secured to the skin at
appropriately selected locations. Mild electrical impulses are then
passed into the skin through the electrodes to interact with the
nerves lying thereunder. As a symptomatic treatment, TENS has
proven to effectively reduce both chronic and acute pain of
patients. However, TENS has shown no capacity for curing the causes
of pain, rather the electrical energy simply interacts with the
nervous system to suppress or relieve pain.
[0004] The human nervous system essentially serves as a
communication system for the body wherein information concerning
the state of the body is communicated to the spinal cord (and/or
brain) and behavioral instructions are communicated from the brain
(and/or spinal cord) to the rest of the body. Thus, there are
ascending neural pathways, such as the ascending pain pathways, and
descending neural pathways, such as the descending inhibitory
pathway (DIP), within the nervous system.
[0005] Briefly, pain impulses received by the free nerve endings of
nociceptive nerve fibers (in particular, A.delta. and C fibers) are
conducted, through various synapses, to the brain. In particular,
these first order neurons enter the dorsal horn of the spinal cord
and synapse with second order neurons, which are either relay
cells, projecting into the brain stem or thalamus, or intemeurons,
synapsing to other intemeurons or to relay cells. The second order
neurons then (mostly) cross the spinal cord and become the
anterolateral system, comprised of the neospinothalamic tract (or
lateral spinothalamic tract) and paleospinothalamic tract. The
nerve fibers of the anterolateral system then terminate in various
regions of the brain, including the brain stem, midbrain and
thalamus.
[0006] Inhibition (or modulation) of pain, by the body, can occur
anywhere from the point of origin of the pain through the
successive synaptic junctions in the pain's central pathway. For
example, following the descending inhibitory pathways (DIP) of pain
inhibition/modulation, stimulation in the cerebral cortex of the
brain descends to the thalamus and then to the periaqueductal gray
(PAG) of the midbrain. The PAG region is rich in opiate receptors
responsible for secreting morphine-like enkephalins and endorphins.
Nerve fibers from the PAG then descend to the nucleus raphe magnus
(NRM) in the brainstem. The NRM is responsible for the secretion of
serotonin, a compound that is instrumental in elevating pain
threshold levels and combating depression. Fibers from the NRM then
descend into the spinal cord, synapsing with other inhibitory
interneurons to cause secretion of additional powerful anti-pain
neurotransmitters such as gamma-aminobutyric acid (GABA).
[0007] While prior art TENS devices and methods have been shown to
be capable of affecting the ascending pathways of pain perception,
they have shown little or no ability to affect the descending
inhibitory pathways of the nervous system. The precise mechanisms
by which these prior art TENS methods operate to affect pain are
not known; however, one theory suggests that, by producing fast
electrical waves that travel up the A.beta. nociceptive fibers, the
TENS electrical stimulation pulses block pain stimulus traveling up
the A.delta. and C fibers. One frequently reported problem with the
prior art TENS methods is acclimation or accommodation; that is,
the patient acclimates to the transcutaneous stimulation and the
pain returns. The intensity of the treatment, in such cases, is
increased to overcome the patient's accommodation of the treatment,
but shortly, a maximum level of intensity is reached and further
treatment is ineffective.
[0008] A TENS simulator such as that shown in U.S. Pat. No.
5,052,391 is, in effect, an electrical pulse generator which
delivers electrical pulses (or impulses), transcutaneously, at a
predetermined fixed or variable frequency. Typically, TENS
stimulators deliver electrical pulses at frequencies in the range
of about 50 to 200 Hertz (Hz). Most commonly, variable frequency
TENS devices operate by beginning stimulation at the lowest
frequency setting then increasing the frequency of stimulation
until a pre-defined event occurs, such as motor nerve response or
patient comfort achieved. Such increases in frequency may be
controlled by a doctor or other medical personnel or, more often,
are controlled by the patient him/herself. In addition to
increasing the frequency of the stimulation pulses, the patient may
be treated by simultaneously increasing the intensity (or
amplitude) of the stimulation output of the device.
[0009] For example, the patient may have a choice of different
"levels" of stimulation, each sequential level providing an
increased frequency and intensity of stimulation as compared to the
previous level. In either case, the output parameters generally
start at their lowest level and are increased over the duration of
the treatment.
[0010] Normally, when the patient (or other operator) increases the
stimulation level of the TENS machine, in accordance with his/her
doctor's instructions, the new, higher level is somewhat
uncomfortable at first. However, as the patient knows from
experience, his/her body accommodates to the new higher level of
stimulation within a tolerable length of time. Once stimulation at
one level becomes fully accommodated, that is, no longer works well
to relieve the symptoms for which the treatment is being
administered, the patient increases the stimulation level. Thus, as
mentioned previously, the body is able to adjust to the electrical
stimulation, requiring ever increasing levels of stimulation to
achieve the same level of pain relief, often until no amount of
stimulation is effective. The use of devices of this general type
for dental anesthesia is shown in U.S. Pat. Nos. 4,924,880 and
4,550,733. These devices generally employed a biphasic symmetrical
sinusoidal waveform at a peak voltage of only 2 volts and a peak
current of only 0.87 milliamps.
[0011] In some cases, the treatment frequency of the TENS device is
fixed by design, or is established as a preselected, generally
arbitrary, rate at the time of treatment, and only adjustment of
the intensity (or amplitude) of the electrical pulses is allowed.
The typical intensity level of TENS stimulators is in the range of
30-200 volts. The waveform characteristic of the electrical pulses
varies and includes, for example, symmetrical sinusoidal waveforms,
symmetrical biphasic waveforms and DC needle spikes. Generally, the
different waveforms are believed to offer some advantage over other
waveforms; however, there has been no clear consensus that any
particular type of waveform is consistently more advantageous than
other types. What is known, however, is the general shape of the
action potential waveform that is responsible for producing
electrical activity in neurons. Characteristic of this action
potential are a very fast rise time and a slow decay.
[0012] The precise mechanisms by which transcutaneous electrical
stimulation operates to control pain are not known. When used to
treat pain, the patch electrodes of the TENS device are generally
attached to the patient in the vicinity of the pain. Thus, for
example, in treating joint pain, electrodes would be affixed near
the joint and stimulation administered thereto. This localized
stimulation then affects the nervous system to reduce the patient's
perception of pain, presumably by either affecting the pain signals
being sent from the region to the brain or by affecting the brain's
perception of the signals it is receiving from the region. Even the
body's natural mechanisms for perceiving and affecting pain are
poorly understood. However, it is known that various biochemicals
are released by nerve and brain cells in response to chemical
and/or electrical stimulation of those cells. These
neurotransmitters assist in the transmission of electrical messages
between and within the peripheral and central nervous systems.
[0013] In contrast to the TENS devices and methods used to affect
the ascending pathways of the nervous system, implantable
electrical stimulators have been used to affect descending motor
pathways of the nervous system. These electrical stimulators are
surgically implanted into the patient's brain in order to affect,
by direct electrical stimulation, specific regions of the brain.
For example, by implantation of a stimulating electrode into the
appropriate brain region, such as the thalamus and/or basal
ganglia, nervous activity within the brain can be affected and the
symptoms of movement disorders, such as akinesia, bradykinesia or
rigidity and hyperkinetic disorders, can be reduced. See for
example U.S. Pat. No. 5,716,377, Rise, et al., the entirety of
which is hereby incorporated by reference. Thus, by stimulating the
brain in this manner, the skeletal muscles at the termination of
the descending motor pathway are affected. Obviously, surgical
implantation of an electrode into the brain, as well as direct
electrical stimulation of the brain are risky procedures that are
preferably utilized only in the most extreme cases and after
failure of less risky procedures.
[0014] Various disease conditions and disorders involve the brain
and/or nervous system and thus may be amenable to treatment using
drugs and/or electrical stimulation. For example, U.S. Pat. No.
5,716,377, issued to Rise, et al., Feb. 10, 1998, describes a
method of treating movement disorders by means of an electrode
implanted into the brain of the patient. Similarly, U.S. Pat. No.
5,713,923, issued to Ward, et al., Feb. 3, 1998, describes a method
of treating epilepsy using a brain implanted electrode in
combination with one or more drugs. While the effects of electrical
stimulation of certain specific nerves, specific nerve/brain
regions and/or specific muscles to treat different diseases and/or
disorders have been described, few if any generalizations have
resulted therefrom. That is, it is still very difficult to predict
what if any type of nerve stimulation or drug therapy will work for
any given disorder.
[0015] Essential tremor (E.T.) is a movement disorder afflicting
more than 5 million people in the United States alone. This
disease, which is the most common adult movement disorder, is about
20 times more prevalent than the tremors associated with
Parkinson's Disease and is a poorly understood hereditary disorder.
It is estimated that 32 in 1000 persons over the age of 60 years
suffers from E.T. About 95% of those with this disease experience
tremors, i.e. uncontrollable shaking, in both hands, often
rendering the hands useless or near useless. Further, E.T. is the
primary cause of head tremors (Titubation), which tremors are not
only extremely difficult to treat but are particularly embarrassing
and debilitating. In particularly severe cases, E.T. patients have
elected to undergo difficult and dangerous brain surgery wherein
the part of the brain responsible for the tremors is destroyed.
Unfortunately, this surgery can result in the unintended permanent
impairment or destruction (i.e., paralysis) of movement speech
and/or swallowing functions as well as paraesthesia or tingling
sensations in the patient's hands and/or head.
[0016] The current treatment of choice for essential tremor is drug
therapy. However, an estimated 60% of E.T. patients do not respond
to drug therapy and must therefore either live with the condition
or resort to more dangerous and more invasive forms of treatment.
Even when drug therapy is "successful," it rarely results in
diminution of head tremors; rather, only hand tremors may respond
to the therapy. Further, the patient's body usually acclimates to
the drug therapy, requiring increased dosages of drugs, which,
after time, become less effective. This necessitates frequent
changes in drugs in order to obtain or maintain the same level of
relief.
[0017] Prior to 1997, in the U.S.A., the only alternative to drug
therapy for the relief of the symptoms of essential tremor was
surgical destruction of part of the thalamus, from where the
tremors are believed to originate. In 1997, (1995 in Europe), an
implantable electronic stimulating device was approved for the
treatment of essential tremor. This device is implanted deep into
the thalamus of the patient and electrical stimulation of that
brain structure is used to control the tremor. However, the device
is effective to control tremors only unilaterally, that is in only
one hand. Further, the success rate of the device is not great,
particularly given the invasive nature of the procedure: with about
67% of 113 Parkinson's disease patients in one study experiencing
control of tremors and about 58% of 83 essential tremor patients in
the study being relieved. Because almost all essential tremor
patients suffer bilateral tremors (tremors in both hands), those
wishing to have the brain implant must choose which hand to
control, at least unless and until more than one implant may be
used simultaneously, a procedure that to date has not been
approved. Also, the brain implant has no effect on titubation (head
tremor).
[0018] A prior art implantable brain stimulation device is
described for example in U.S. Pat. No. 5,716,377, issued to Rise,
et al. and incorporated herein, in its entirety, by reference. This
patent describes the use of an implantable device having the
stimulating electrode implanted into the basal ganglia or thalamus
of the patient, with the electrode lead passing under the skin of
the patient to a pulse generator also implanted subcutaneously.
Also described in the '377 patent, is the implantable device
including a sensor for sensing the tremors. The sensor is also
implanted and is connected to the pulse generator. The brain
stimulation device is operated at 0.1 to 20 volts and at a
frequency of between 2 to 2500 Hertz. Such devices are expensive,
about $10,000 for the device plus about $25,000 for the required
surgery, and require replacement of the pulse generator, and hence
additional surgery and expense, about every three years.
[0019] Like essential tremor and Parkinson's disease, dementia
disorders such as Alzheimer's disease are primarily diseases of the
brain. Alzheimer's disease is a degenerative disease in which nerve
cells within the brain die and their connections deteriorate. It is
the most common cause of dementia and is the fourth leading cause
of death among adults in the United States. While various causative
factors have been postulated, such as heredity, environmental
toxins and biochemical changes within the aging body, no specific
cause for this disease had been identified.
[0020] Alzheimer's patients consistently have abnormally low levels
of neurotransmitters in their brains, particularly a
neurotransmitter known as acetylcholine. This reduction in
neurotransmitters results in the gradual deterioration of the
patient's mental processes and intellectual functioning, including
memory loss, especially short-term memory, behavioral changes,
inability to properly use language and the inability to perform
skilled activities. Autopsies of Alzheimer's patients reveal the
formation of protein plaques, comprised primarily of beta-amyloid
protein, within the critical memory and learning centers of the
brain. Studies on rats have demonstrated that injection of
substance P can block the nerve damage caused by beta-amyloid, and
thus, a significant portion of research efforts aimed at
controlling this disease have focused on this and other brain
biochemicals.
[0021] Presently, there is no cure or prevention for Alzheimer's
disease. However, two different drugs have been approved in the
United States for use in the management of this disease. While
neither drug has been proven to provide long term relief from the
degenerative process of Alzheimer's, at least one of the drugs has
recently demonstrated an ability to stop the decline in memory and
alertness for 84% of patients studied for a six month period.
Further this drug, known as Aricept (produced by Eisai, a Japanese
company), does not apparently cause the liver-toxic side effects
seen with the other approved drug. Thus, research on drug therapies
for the treatment of Alzheimer's disease continue.
[0022] Recently, the treatment of dementia disorders by electrical
stimulation of specific cranial nerves has been described. U.S.
Pat. No. 5,269,303, issued to Wernicke, et al., Dec. 14, 1993,
describes stimulation of the vagus nerve to treat patients with
dementia, and U.S. Pat. No. 5,540,734, issued to Zabara, Jul. 30,
1996, describes stimulation of one or both of the trigeminal and
glossopharyngeal nerves to treat a variety of neurological, medical
and psychiatric disorders, including dementia disorders. Each of
these patents are hereby incorporated by reference in their
entirety. Unfortunately, however, these methods are premised upon
implantation of stimulation electrodes directly onto the specified
nerve. This not only means that the patient must undergo major
surgery to receive treatment, but also that the scope of treatment
will be limited to the specific nerves upon which the electrode is
implanted. Thus, once implanted, should the device not work to
relieve the symptoms of the dementia or, worst, should the nerve
stimulation result in intolerable side effects, either the device
must be surgically explanted or must be deactivated and left within
the patient's body.
[0023] Thus, what is needed is an inexpensive non-invasive method
of treating neurology-related disorders, such as dementia disorders
and/or movement disorders, that will be effective to relieve the
very severe symptoms associated therewith. In particular, with
respect to movement disorders, such as essential tremor and tremors
associated with Parkinson's disease, methods of providing relief
for both bilateral hand tremors and head tremors is needed.
Similarly, with respect to dementia disorders, such as Alzheimer's
disease, even a slowing of the deterioration associated with the
disorders would be welcomed. Also desired is an improved way of
creating nerve blocks through the use of electroanesthesia so as to
provide a patient with localized comfort when pain would otherwise
be experienced.
SUMMARY OF THE INVENTION
[0024] The present invention addresses these and other objectives
by providing methods for the non-invasive treatment, control and/or
prevention of various disease conditions and disorders using
transcutaneous electrical stimulation, wherein a plurality of
stimulation intensities and a plurality of stimulation frequency
parameters are employed such that the entire plurality of frequency
parameters is administered, from highest to lowest frequency, at
each of the plurality of stimulation intensity parameters. Further
provided herein are apparatus for employing these methods.
[0025] In one aspect, the present invention provides improved
results in the treatment of various diseases by affecting the
descending inhibitory pathways and neurotransmitter production and
release within the nervous system. In particular, such results are
achieved via transcutaneous nerve stimulation, a method which
heretofore had not been described or demonstrated, and which has
also been found to be effective to administer nerve block
electroanesthesia.
[0026] In a preferred embodiment, the method contemplated herein,
is useful to treat, control and/or prevent tremor disorders, such
as essential tremor and tremors associated with Parkinson's
disease, dementia disorders, such as Alzheimer's disease, and
cortical, subcortical and multi-infarct dementia and painful
degenerative disorders, such as fibromyalgia and reflex sympathetic
dystrophy. This preferred method involves stimulating at a first
highest frequency parameter and lowest intensity parameter;
decreasing the frequency parameter to the lowest frequency
parameter over the course of time and in a specified manner, while
holding the intensity parameter constant. The next stage in
treatment is to increase the stimulation frequency parameter back
to the highest frequency parameter but at a next higher stimulation
intensity parameter. The stimulation frequency parameter is then
decreased in the same manner as previously done for the lower
intensity parameter; while the intensity parameter is maintained at
this next highest level.
[0027] The apparatus contemplated for use herein is a high
frequency, high intensity transcutaneous electrical nerve
stimulator (TENS) similar to that described in U.S. Pat. No.
5,052,391 ('391 patent), issued to Silverstone, et al., the
entirety of which patent is hereby incorporated by reference. In a
preferred embodiment, the TENS device described in the '391 patent
is modified to include a programmable microprocessor capable of
retaining and executing at least one, and preferably a plurality,
of stimulation programs according to the new methods described
herein and further is a digital device instead of analog as
described in the '391 patent. Most preferably then, the improved
TENS device contemplated herein may be programmed to administer an
entire regimen of therapy to a patient without requiring any
control on the part of the patient, while still permitting the
patient the opportunity to control the device if desired. Further,
the device will preferably be able to administer a plurality of
treatment regimens, thereby being useful for a plurality of
different disease states and disorders.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Additional aspects, features and advantages of the present
invention will be apparent to those of skill in the art upon
reading the following detailed description and referring to the
accompanying drawings in which like numbers refer to like parts
throughout and in which:
[0029] FIG. 1 is a block diagram of a preferred transcutaneous
neurostimulator for use in accordance with the methods described
herein.
[0030] FIG. 2 is a schematic of a frequency curve preferred for use
in treating tremor disorders;
[0031] FIG. 3 is a schematic of an alternative frequency curve,
preferred for use in treating dementia disorders and acute and
chronic pain;
[0032] FIG. 4 is a schematic of an alternative frequency curve,
preferred for use in treating painful degenerative disorders, such
as fibromyalgia and reflex sympathetic dystrophy; and
[0033] FIG. 5 is a schematic of an alternative frequency curve,
preferred for use in treatment of pain and induction of electronic
nerve block anesthesia and electroanesthesia.
[0034] FIG. 6 is a graph of results of neurochemical blood assays
taken from a patient before, during and twenty-four hours following
treatment in accordance with the methods herein.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The nervous system, including the brain, operates as a
communication network for the body, carrying information and
instructions from the brain to the rest of the body, from the rest
of the body to the brain and within the nervous system itself. In
performing these functions, the nervous system and brain, among
other things, use certain biochemical messengers, known as
neurotransmitters, to accomplish this transferring of information
and instructions. It has been known for some time that electrical
stimulation of nerves, for example by implantation of a stimulating
electrode onto a particular nerve, can result in release of one or
more neurotransmitters from nerve cells thereby affecting the
operation of this communication system.
[0036] Numerous disease states and disorders involve the nervous
system and/or brain, many of which are believed to affect or result
from the activity or lack of activity of neurotransmitters. For
example, tremor disorders such as essential tremor and Parkinson's
disease, dementia disorders, such as cortical dementia, as is found
in Alzheimer's disease and Pick's disease, subcortical dementia, as
is found in Parkinson's disease, Huntington's chorea and
supranuclear palsy, and multi-infarct dementia; and painful
degenerative disorders, such as fibromyalgia and reflex sympathetic
dementia all involve the brain and/or nervous system and may be
related to neurotransmitter activity.
[0037] In preferred embodiments of the new methods described and
claimed herein, transcutaneous electrical nerve stimulation
techniques are employed to treat, control and/or prevent these and
other disorders. While the use of transcutaneous nerve stimulation
for such purposes is not unknown, the particular new methods
described herein are uniquely effective. For example, in preferred
embodiments, the methods described herein result in increases in
blood levels of neuro-transmitters, a heretofore unknown
phenomenon. Most prior art transcutaneous nerve stimulators operate
by delivering electrical stimulation to the body at a moderately
low to very low frequency and at a single level of intensity.
Usually, the patient is able to adjust either or both of the
frequency and intensity, but the device then stimulates for the
duration of the treatment at only those selected parameters. In
contrast, the methods presented herein operate by stimulating, in a
defined pattern, at a plurality of frequencies beginning at a very
high frequency and sweeping through the plurality of frequencies to
the lowest frequency, while maintaining the intensity of the
stimulation at a single low intensity. Once a single sweep has been
performed the intensity of the stimulation is incrementally
increased and the entire frequency sweep performed at the new
higher intensity.
[0038] In general, the frequency ranges that are preferred for the
methods described and claimed herein are from about 60,000 Hertz to
100 Hertz, and most preferably from about 40,000 Hertz to 400
Hertz. This is in stark contrast to most transcutaneous electrical
stimulating devices and methods which operate in the range of about
50 Hertz to 200 Hertz. Preferably, the duration of treatment at a
single level of intensity, that is the time spent stimulating
through a single sweep of frequency parameters, is 1 to 30 minutes.
More preferably, the time is 1-20 minutes and most preferably 1-15
minutes. The range of acceptable stimulation intensities is not
critical, but is generally from about zero to 100 volts, and in
preferred embodiments is zero to 60 volts. The preferred
stimulating device operates at about 40 mamps, but this too is not
critical. What is important is that the general method of sweeping
through the entire plurality of frequency parameters, along the
frequency curve, occur for at least two sequentially increasing
levels of intensity. Thus, for example, in a most preferred
embodiment, as described further below, the maximum output voltage
(intensity) of the device is equally divided into ten different
intensity parameters (or levels); such as 5.7 volts at the lowest
parameter (level 1), 10.4 volts at the second parameter (level 2),
and so on up to 57 volts at the highest intensity parameter (level
10). While not all intensity levels are necessarily used in a
single treatment program, those levels that are used are used for
an entire, single sweep of the frequency curve.
[0039] Turning then to FIG. 1, illustrated is a block diagram of a
preferred transcutaneous neurostimulator for use in practicing the
improved methods described herein. This preferred transcutaneous
nerve stimulation apparatus has digital frequency generation and
provides two independent channels of bipolar, variable frequency,
variable amplitude, and patient output signals. These output
signals are coupled to the patient via skin electrodes, preferably
two per channel. The frequency and amplitude of the outputs are
preferably adjustable via front panel switches, or, in the case of
frequency, also by a hand-held remote control. LED numeric and bar
graph displays on the front panel may be used to provide the
operator with a visual indication of amplitude (intensity) and
frequency (bias) settings. The device is preferably battery powered
and microprocessor controlled. Thus, the preferred apparatus is,
conceptually, a two channel, variable frequency, variable
amplitude, square wave frequency generator. As discussed in detail
below, the apparatus preferably commences its operations at a
highest frequency output and is reduced at a predefined rate, to a
lowest frequency as other output parameters are increased
(amplitude & current). This frequency sweep is preferably
repeated over each of ten increasing intensity levels.
[0040] Preferably, the transcutaneous stimulator apparatus
contemplated for use herein has five input/output connectors
mounted on the back of the apparatus enclosure. These include, for
example, an output connector for each channel, an input connector
for battery charging, an input connector for the remote hand-held
controller, and outputs for the treatment recorder. The battery
employed in the apparatus is preferably a 12 volt, rechargeable gel
cell. It supplies power for the entire system. It is recharged by
connecting a wall mount charger to the charger input connector.
Such a battery generally has a life of several hours depending,
somewhat, upon the bias and amplitude settings used by the patient,
as well as upon the individual patient load.
[0041] As contemplated herein, the front display of the apparatus
is a membrane switch overlay with "smoked" transparent windows to
allow display viewing. Displays include, for example, eight LED
numeric digits and two 10 element LED bar graphs, with the
following variables preferably being displayed: Channel 1 Intensity
(2 digits plus decimal); Channel 1 Bias (2 digits plus decimal plus
10 bars); Channel 2 Intensity (2 digits plus decimal); and Channel
2 Bias (2 digits plus decimal plus 10 bars). Two additional LED
elements are also preferably included on the front panel display,
one indicating "Power On" and the other indicating "Battery
Charging". Each channel preferably has five control switches:
channel On/Off; Intensity Up; Intensity Down; Bias Up; and Bias
Down. The membrane switch panel connects to the display board,
which in turn connects to the microprocessor board. Via this
connection, the microprocessor can detect when a front panel switch
closure occurs and appropriately control the displays and patient
output.
[0042] As shown in FIG. 1, a microprocessor board 20, containing
the majority of the circuitry, is provided. The microprocessor 20
may be, for example, an 8 bit Motorola 68HC11 device utilizing
external EPROM 22 for program memory. The EPROM 22 memory
preferably is about 8K bytes and is interfaced to the processor
with an address latch and appropriate strobe decode logic. The
processor clock preferably operates at about 8 MHZ and is crystal
controlled. The processor communicates with the remaining circuitry
via input/output ports, one of which includes an internal analog to
digital converter. When the unit is switched on, the processor is
momentarily at rest and then begins fetching and executing
instructions from the EPROM memory. As long as the unit is switched
on, the processor is running (fetching and executing instructions).
The main functions of the processor are to read the operator
control switches and remote hand-held controller, adjust the
amplitude and frequency of the outputs, and send related data to
the display board for display.
[0043] In the preferred embodiment, the On/Off switch and the
emergency shut down switch relay 24 are in series with the positive
pole of the 12 volt battery. Thus, when either of these switches
are Off, no battery current flows to the microprocessor board. When
On, 12 volts DC is supplied to the microprocessor board. The
emergency shut down switch circuit employs an SCR to latch the
relay in or out. Thus, once tripped this circuit is only reset by
turning the main power off and then back on again.
[0044] The 12 volts is supplied primarily to three areas: a 5 volt
regulator 26; a DC step up regulator 28; and a low battery
detection circuit 30.
[0045] The 5 volt regulator 26 can be a standard linear, series,
in-line regulator. The output is then a regulated 5 volts and
provides the operating power supply for the majority of the
circuitry (microprocessor, memory, display board, etc.). The DC
step up regulator 28 is an inductive switching regulator used to
increase the 12 volt DC input to an approximately 40 volt DC
output. The switching regulator oscillates at a high frequency,
varying with load. On one cycle of the oscillation, current passes
through the inductor building up a magnetic field. On the alternate
cycle the field collapses, inducing a high voltage which is stored
in a large capture capacitor. The capture capacitor positive pole
is the 40 volt output point and is fed back to the switching
regulator circuit to cause a closed loop regulation of this
voltage. The switching regulator varies frequency and duty cycle in
order to maintain the output at 40 volts DC. This 40 volts is the
supply voltage for the output stage intensity control amplifiers. A
low battery detection circuit 30 is also provided. It determines
when the 12 volt battery drops below a predetermined value, then
trips the hardware interrupt on the processor and forces it to
transition to a safe state and shut down. In addition, this is
signaled to the operator by displaying "bA Lo" or similar
informative message, on the display board 52.
[0046] One of the main functions of the processor is to monitor the
user remote control 32 and front panel switches 34. The user remote
control 32 is preferably a simple linear, slider potentiometer. It
is connected across power (5+volts) and ground with its wiper
forming the output. Thus, its output is a DC voltage somewhere
between +5 volts and ground depending on wiper position. This
signal is fed into an analog to digital converter input on the
microprocessor. The A/D converter preferably has a resolution of 8
bits. Thus, the DC 0 to 5 volt input is converted to a digital
number 0 to 255. This is then used by the processor to control the
output bias setting (frequency). It should be noted that bias and
frequency are inversely related; that is, a bias of 0.0 results in
the highest frequency and a bias of 9.9 is the lowest
frequency.
[0047] Each of the ten front panel switches are connected to an
individual microprocessor port. The other side of all switches are
connected to system ground. Also connected to each port is a pull
up resistor to +5 volts. Thus, when the switches are open
(unpressed), the port pins sit at +5 volts. When a switch is
pressed, its associated port pin is forced to ground (0 volts).
During operation of the preferred apparatus, the processor
continually monitors these port pins, looking for a key press or
change in remote control slider position. When detected, the
appropriate action is taken.
[0048] A second important function of the processor in this
preferred apparatus is to control the bias (frequency) and
intensity (amplitude) of the outputs. The outputs are
transformer-coupled to the patient. The patient is connected to the
secondary side of a 1:1 transformer 46, 48 (one per channel). One
lead of the primary side of the transformer is connected to the
intensity drive circuitry 36, 38 and the other lead is connected to
the bias drive circuitry 40, 42. The intensity drive circuitry 36,
38 is merely a DC voltage amplifier whose input in 0 to 5 volts,
which is translated to 0 to 40 volts on the output. The input
signal comes from a digital potentiometer 44 which is under control
of the microprocessor 20. Thus, the processor 20 sends a digital
byte to the digital potentiometer 44. The potentiometer 44 converts
this into a voltage between 0 and 5 volts depending on the
intensity setting. The intensity drive circuitry 36, 38 converts
this into a voltage between 0 and 40 volts, which appears on one
end of the transformer 46, 48 primary.
[0049] The bias drive circuitry 40, 42 is preferably a transistor
power switch which pulls the other end of the transformer primary
46, 48 to ground when it is on, or lets it float (unconnected) when
it is off. Thus when this switch is on, current flows through the
primary at a level determined by the intensity setting (0 to 40
volts). When this switch is off, no current flows through the
primary. The input to the bias drive circuitry is preferably a
square wave created by a dual channel programmable timer 50. The
timer is connected to the processor/memory bus and is programmed by
the processor 20 to create a specific square wave frequency based
on bias setting. The microprocessor "E Clock" forms the clock
signal for the programmable timer (2 MHZ) 50. Thus, the processor
20 determines bias setting from front panel 34 switch presses and
hand controller position 32. Using the bias setting the processor
20 determines desired frequency from a currently selected frequency
look up table within the processor. The processor 20 then outputs
the necessary commands to the programmable timer 50 to create a
specific frequency output. It should be noted that since the
frequency base to the timer is 2 MHZ, the resolution of frequency
period is 0.5 micro seconds. The square wave output from the timer
50 then drives the digital switch which causes current to flow on
and off, at the desired frequency, through the transformer primary.
In other words, on one side of the transformer primary is a DC
voltage, 0 to 40 volts, set by intensity; on the other side of the
primary is an on/off switch, operating at the bias setting
frequency. The processor 20 also preferably has an over riding
"stop" line (not shown) to each channel which can force the bias
drive circuitry off. In addition, while monitoring the hand
controller 32 to determine bias setting the processor computes rate
of change of hand controller position 32. If this rate of change
exceeds a preset limit an error is detected and the outputs are
switched off. This permits detection of, for example, a hand
controller broken ground wire, or an accidentally moved (bumped)
hand controller.
[0050] The display board 52 contains all the light emitting diode
(LED) numeric and bar graph displays 54 in addition to the display
drivers 56 and two input/output connectors (not shown). One
connector mates with the membrane switch panel to bring front panel
switch connections into the system. The other connector connects to
a 20 pin ribbon cable which connects in turn to the microprocessor
board. Power for the display board, front panel switch signals, and
LED drive signals all flow through this ribbon cable.
[0051] Finally, in this most preferred embodiment of the apparatus,
there are three driver integrated circuits on the display board.
These provide direct drive for all the bar graph and numeric LED
displays on the board. These drivers form a serial data link to the
processor via the ribbon cable. Thus, the processor decides which
LED's should be on and shifts out the appropriate serial data word
to effect this. To conserve battery life the LED's are multiplexed
on a 50% duty cycle, that is, at any one time, only half the LED's
are on. This multiplex rate is faster than the human eye can
perceive and thus the appearance is that all displays are
constantly illuminated. To further conserve battery power the bar
graph is preferably lighted in a climbing, one bar-at-a-time mode.
All of the numeric, multiplexing, and bar graph decoding preferably
takes place in the processor 20 under software control. The drivers
merely turn on LED's bit for bit as instructed by the processor
Referring now to FIG. 2, illustrated is a frequency curve preferred
for use in treating tremor disorders, such as essential tremor and
tremors associated with Parkinson's disease. It is this same curve,
then, that is used at every intensity level at which stimulation is
provided to the patient. Thus, at each intensity level, a range of
stimulation frequencies is provided to the patient, beginning at
about 40,000 Hz and decreasing to about 400 Hz, at the rate
indicated by the frequency curve illustrated in FIG. 2. The
following detailed example is illustrative of a preferred treatment
process for tremor disorders.
[0052] First, two pair of self-adhesive electrodes are affixed to
the patient's skin. Suitable electrodes are well known to those of
skill in the art, for example Bio-Skin Silver electrodes (Synaptic
Corp., Aurora, Col.). One pair is placed bilateral to the spine at
C6, with approximately one inch between the inner medical borders
of the electrodes. The second pair is affixed bilateral to the
spine at L5, also spaced about one inch from one another as
measured at the inner medical borders. Both pairs of electrodes are
operatively attached to the electrical stimulator (i.e. pulse
generator), which is most preferably preprogrammed with the desired
treatment program thereby permitting the doctor, other medical or
lay personnel or the patient his/herself to very easily activate
the program. The next step is to turn on the electrical stimulator
and begin the treatment program.
[0053] Generally, when the method is employed to treat, control or
prevent a disorder selected from the group consisting of essential
tremor and Parkinson's disease and wherein the step of
incrementally decreasing the stimulation frequency parameter is
performed for a time duration (T), one may employ the following
sequential steps of a) steadily decreasing the stimulation
frequency parameter about 70% over the time period 0.1T; b)steadily
decreasing the stimulation frequency parameter about 5% over the
time period 0.1T; c) steadily decreasing the stimulation frequency
parameter about 20% over the time period 0.7T; and d) steadily
decreasing the stimulation frequency parameter the remaining about
5% over the remaining time period of 0.1T, wherein the percentages
are of the total frequency parameter range from the lowest
frequency parameter to the highest frequency.
[0054] Electrical stimulation preferably begins at the highest
stimulation frequency and lowest stimulation intensity for the
programmed treatment. As illustrated in FIG. 2, the highest, and
therefore initial, stimulation frequency is preferably about 40,000
Hz for treatment of tremor disorders. Preferably, the frequency
curve of FIG. 2 is administered in a plurality of individual
stimulation frequency parameters, and most preferably in about 100
different frequency parameters. These 100 different stimulation
frequency parameters may, for example, be numbered as 0.0 through
9.9 (or 0.1 through 10.0). Preferred settings for some of the 100
points along the frequency curve illustrated in FIG. 2 are as
follows:
1 TABLE C Frequency Parameter Number Frequency (Hz) 0.0 40,000 0.5
21,000 1.0 10,000 1.5 9,100 2.0 8.500 2.5 8,000 3.0 7,500 3.5 6,500
4.0 6,000 4.5 5,500 5.0 5,000 5.5 4,500 6.0 4,000 6.5 3,500 7.0
3,000 7.5 2,500 8.0 2,000 8.5 1,500 9.0 1,000 9.5 500 9.9 400
[0055] It is preferred to use at least about ten intensity levels,
wherein the total output voltage available is equally divided among
the ten (or more) levels. The maximum voltage output is not
critical, but is preferably in the range of about 40-150 volts, and
most preferably about 50-100 volts, peak to peak. A preferred
tremor treatment program, in accordance with the present invention
is about 45 minutes in duration, delivers stimulation according to
the above described frequency curve and employs all 10 intensity
levels according to the following schedule:
2 Intensity Level Time (minutes) 1 1 2 2 3 2 4 4 5 4 6 4 7 4 8 8 9
8 10 8
[0056] At each intensity level, only one sweep of the stimulation
frequency curve is performed. Thus, for example, at the lowest
intensity level, level one, the stimulation frequency is reduced in
one minute from about 40,000 Hz to about 400 Hz, following the
curve illustrated in FIG. 2; whereas at intensity level 10, the
highest intensity level, the stimulation frequency preforms the
same pattern of decreasing from 40,000 to 400 Hz, but does so in
eight minutes.
[0057] A patient, D. P., was treated in the manner just described,
except that the highest stimulation frequency used was 30,000 Hz.
D. P. had a ten year history of essential tremor. He suffered
bilateral hand tremors. In his left hand, the tremors were so bad
he could not touch his nose. While various drugs had brought D. P.
some relief over the years, they slowly became ineffective, even at
very high doses. D. P. was not a suitable candidate for
implantation of a brain stimulator and thus, agreed to undergo this
experimental transcutaneous electrical stimulation program. After
his first 45-minute treatment, he remained tremor-free for four (4)
hours. Daily treatments for the subsequent 14 days provided
complete cessation of his tremors over each 24 hour period. D. P.
has been receiving such treatment for over a year, and his tremors
are still well controlled, despite receiving treatment only about
three times a week. He has described the severity of his tremors as
a 2 on a scale of 1-10 with 10 being the most severe tremors, and 1
being tremor-free.
[0058] Since beginning treatment on D. P., other patients suffering
with tremor disorders have been treated on an experimental basis.
The results, to date, have been consistent with those observed in
D. P. Both bilateral hand tremors and head tremors (titubation)
have been successfully treated using this new method and device.
This is in stark contrast to the brain implant devices which have
only been demonstrated useful in controlling tremors in one hand
and not at all in the head. It is noted that, preferably, the
patient (or doctor or other medical or lay personnel controlling
the electrical stimulation) may stop the electrical stimulator at
any time by pushing a single button. This control is important so
that the patient does not experience unnecessary pain or discomfort
during treatment.
[0059] It is believed that among other things, the general method
of transcutaneous electrical stimulation described and claimed
herein modulates both the ascending and descending pathways of the
nervous system resulting in the release of neurotransmitters that
then favorably affect the brain to control the symptoms of the
disease being treated. In the case of treatment of tremor
disorders, for example, it is believed that the thalamus and Basal
Ganglion (the thalamocortical circuits) are stimulated by this
method to provide control of both bilateral tremors and head
tremors.
[0060] FIGS. 3-5 each illustrate alternative, preferred frequency
curves for treating various disease states and disorders. For
example, FIG. 3 illustrates a frequency curve particularly useful
for treating dementia disorders. FIG. 4 illustrates a frequency
curve particularly suited to treatment of painful degenerative
disorders such as fibromyalgia and reflex sympathetic dystrophy,
and FIG. 5 is particularly useful for inducing
electroanesthesia.
[0061] As with the method described above for treating tremor
disorders, in preferred embodiments, the frequencies represented by
these curves are administered as a plurality of frequency
parameters and most preferably are administered as about 100
frequency parameters. Also in accordance with the general method of
the present invention, a plurality of stimulation intensities are
employed and the entire plurality of frequency parameters are
administered at each intensity level.
[0062] For example, in treating a patient suffering with a dementia
disorder, such as Alzheimer's disease, the patient first has two
pairs of electrodes affixed to the skin in about the same location
as described for treatment of tremor disorders; that is bilateral
to the spine at C6 and L5. The leads of the electrodes are
operatively connected to the electrical stimulator and the
appropriate program initiated. As with the tremor treatment
described above, the stimulation program to be used for treating
the dementia patient is most preferably preprogrammed so that no
adjustment thereto need be made by the patient (other than, of
course, termination of the treatment should such be desirable or
necessary). Once the electrodes are properly affixed to the patient
and the leads connected to the electrical stimulator, the unit is
switched on.
[0063] Generally, when the method is employed to treat, control or
prevent a disorder selected from the group consisting of
Alzheimer's disease, cortical dementia, subcortical dementia and
multi-infarct dementia and wherein the step of incrementally
decreasing the stimulation frequency parameter is performed for a
time duration (T), one may employ the following sequential steps of
a) steadily decreasing the stimulation frequency parameter about
66% over the time period 0.1T; b) steadily decreasing the
stimulation frequency parameter about 23% over the time period
0.2T; c) steadily decreasing the stimulation frequency parameter
about 5.5% over the time period 0.1T; and d) steadily decreasing
the stimulation frequency parameter the remaining about 5.5% over
the remaining time period of 0.6T, wherein the percentages are of
the total frequency parameter range from the lowest frequency
parameter to the highest frequency.
[0064] As previously described, stimulation always begins at the
highest stimulation frequency parameter and lowest stimulation
intensity. The program then decreases the stimulation from the
highest frequency parameter, in this case, preferably about 40,000
Hz, to the lowest frequency parameter, preferably 400 Hz, in
accordance with the frequency curve illustrated in FIG. 3. It is
preferred that about 100 different frequency parameters be used.
The following table provides settings for some of the 100 points
along the frequency curve illustrated in FIG. 3:
3 Frequency Parameter Number Frequency (Hz) 0.0 40,000 0.5 21,000
1.0 12,000 1.5 10,000 2.0 8,000 2.5 6,050 3.0 4,100 3.5 3,175 4.0
2,250 4.5 2,017 5.0 1,785 5.5 1,556 6.0 1,325 6.5 1,162 7.0 1000
7.5 900 8.0 800 8.5 700 9.0 600 9.5 500 9.9 400
[0065] A preferred treatment program for Alzheimer's disease,
according to the present invention, involves slowly stepping up the
maximum intensity of the stimulation over the course of several
treatments. Thus, for example, during the first one-hour treatment
administered to the patient, the stimulation intensity is raised
only to level 7 of 10 (which is preferably 70% of the highest
available intensity level). The one-hour treatments are preferably
administered once a day, and this first level of treatment (i.e.,
wherein the maximum stimulation intensity is only 70% of the
highest available intensity level) is preferably carried out for
about the first ten days (or first ten one-hour treatments). The
second level of treatment, preferably conducted for the
11.sup.th-20.sup.th of the daily treatments, increases the maximum
intensity level to 8 (80% of the highest available intensity
level). Treatments 21-30 provide a maximum intensity level of 9
(90%), and the remaining treatments include the highest available
intensity level (10). The following table shows each of the four
different levels of treatment with the number of one-hour
treatments to be performed at that treatment level (in parentheses)
and provides the duration of stimulation at each intensity level
within each different level of treatment:
4 Level 1 Level 2 Level 3 Level 4 (1-10) (11-20) (21-30) (31-)
Inten- Inten- Inten- Inten- sity Time sity Time sity Time sity Time
Level (min) Level (min) Level (min) Level (min) 1 1 1 1 1 1 1 1 2 2
2 2 2 2 2 2 3 4 3 4 3 4 3 4 4 8 4 8 4 8 4 8 5 15 5 10 5 8 5 8 6 15
6 10 6 8 6 8 7 15 7 10 7 9 7 8 8 15 8 10 8 8 9 10 9 8 10 5
[0066] While a specific rate for moving through the four levels of
treatment is provided, this is meant to be illustrative only.
Individual patients will tolerate the sensations associated with
the transcutaneous stimulation differently. This is particularly of
concern when dealing with Alzheimer's patients or other patients
suffering from dementia, because such patients may be unable to
communicate their level of comfort or discomfort clearly. Thus, the
above schedule of treatment is intended as a guide. In practice,
the doctor or other medical or lay personnel operating the device
should closely monitor the patient for indications that he/she is
becoming uncomfortable with the intensity of stimulation being
administered. As with all the devices contemplated herein, it is
preferred that the stimulation device include a simple mechanism
for terminating stimulation, should such be desirable or
necessary.
[0067] FIG. 4 illustrates a frequency curve preferred for use in
treating painful degenerative disorders such as fibromyalgia and
reflex sympathetic dystrophy, as well as general acute and chronic
pain. Fibromyalgia is a widespread musculoskeletal pain and fatigue
disorder for which the cause is still unknown. Most patients with
fibromyalgia complain of systemic pain, often described as deep
muscular aching, burning, throbbing, shooting and stabbing pain. No
routine laboratory testing is available for diagnosing this
debilitating disorder. Upon physical examination, patients are
usually sensitive to pressure in certain areas of the body.
Currently, diagnosis is made based solely on established criteria
relating to the severity, widespread locality and duration of the
pain.
[0068] Reflex sympathetic dystrophy (RSD) is a very severe form of
chronic pain believed to affect as much as 10% of the entire
population. The chronic pain of this syndrome is typified by a
marked emotional connotation, such as severe anxiety, phobia and/or
neuropsychological disturbances in the form of sever irritation,
agitation and depression.
[0069] As with the specific examples given above for treatment of
tremor and dementia disorders, treatment of fibromyalgia, RSD and
similar painful degenerative disorders involves the administration
of transcutaneous electrical stimulation beginning at a highest
frequency parameter and lowest stimulation intensity level;
decreasing the frequency parameter to a lowest frequency parameter
by stimulating at a plurality of stimulation frequency parameters
therebetween; then increasing the stimulation intensity level to a
next highest intensity level and increasing the frequency parameter
back to the highest parameter, followed by repeating the pattern of
decreasing the frequency parameter to the lowest parameter. In a
most preferred embodiment of treating these degenerative disorders,
illustrated by the frequency curve of FIG. 4, the highest
stimulation frequency parameter is 40,000 Hz and the lowest
frequency parameter is 2,500 Hz. As with the previously described
examples, the maximum output voltage is preferably divided into ten
levels.
[0070] Generally, when the method is employed to treat, control or
prevent a disorder selected from the group consisting of
fibromyalgia, reflex sympathetic dystrophy, general acute pain and
chronic pain and wherein the step of incrementally decreasing the
stimulation frequency parameter is performed for a time duration
(T), one may employ the following steps of a) steadily decreasing
the stimulation frequency parameter about 66% over the time period
0.1T; b) steadily decreasing the stimulation frequency parameter
about 13% over the time period 0.1T; c) steadily decreasing the
stimulation frequency parameter about 6% over the time period 0.1T;
d) steadily decreasing the stimulation frequency parameter about 5%
over the time period 0.2T; and d) steadily decreasing the
stimulation frequency parameter the remaining about 10% over the
remaining time period of 0.5T, wherein the percentages are of the
total frequency parameter range from the lowest frequency parameter
to the highest frequency.
[0071] Thus, the following table provides several frequency
parameters taken from the frequency curve illustrated in FIG. 4. As
with the similar tables provided herein, the frequency parameters
are preferably numbered 0.0 through 9.9, providing 100 different
frequency parameters:
5 Frequency Parameter Number Freqency (Hz) 0.0 40,000 0.5 21,000
1.0 12,000 1.5 9,875 2.0 7,750 2.5 6,775 3.0 5,800 3.5 5,275 4.0
4,750 4.5 4,375 5.0 4,000 5.5 3,760 6.0 3,520 6.5 3,360 7.0 3,200
7.5 3,100 8.0 3,000 8.5 2,850 9.0 2,900 9.5 2,600 9.9 2,500
[0072] Preferably, total treatment times are about 20 minutes and
are, ideally, administered several times a week. However, weekly
treatments have been demonstrated to provide noticeable favorable
results. As with other treatments described herein, the treatment
program typically begins with more time spent at lower intensities,
gradually increasing the duration of stimulation at higher
frequencies in subsequent treatments.
[0073] FIG. 5 illustrates a final exemplary frequency curve for use
in accordance with the present invention. The frequency parameters
comprising this curve have been found to be particularly useful in
inducing electroanesthesia and nerve block anesthesia, as well as
for the general treatment of pain. The following table provides
exemplary frequency parameters taken from the curve illustrated in
FIG. 5:
6 Frequency Parameter Number Frequency (Hz) 0.0 40,000 0.5 25,500
1.0 11,000 1.5 9,500 2.0 8,000 2.5 7,000 3.0 6,000 3.5 4,750 4.0
4,500 4.5 4140 5.0 3,775 5.5 3,410 6.0 3,050 6.5 2,690 7.0 2,325
7.5 1,960 8.0 1,600 8.5 1,300 9.0 1,000 9.5 700 9.9 400
[0074] It will be apparent that where nerve block anesthesia (or
electroanesthesia) is the goal, a single "treatment" is preferably
performed. Generally, one pair of smaller electrodes, for example
about 1.25 inches in diameter, are placed in the vicinity of the
nerve to be blocked about 1 inch apart. A second pair of larger
electrodes, for example about 2 inches in diameter, are placed
about 1 inch apart either bilateral the spine at about C5 or on the
opposite side of the body from the location of the first electrode
pair. Stimulation is begun at a relatively high intensity and is
manually increased as high as is reasonably tolerable to the
patient, usually to a level of about 70%-90% of 60v maximum
intensity of the neurostimulator described hereinbefore, i.e. about
40 to about 55v. The waveform employed has a fast rise time and a
slow decay, which has been found to provide a particularly
advantageous biological approach in that it stimulates the Action
Potential responsible for producing electrical activity in human
neurons. The intensity is then held at that level while the
stimulation frequency is decreased to a lower frequency. The
original decrease in frequency may be carried out in a manner that
can be accommodated by the patient to reach an initial tolerable
stimulation level, with the frequency level being decreased
increment by increment thereafter. Alternatively, the program is
used which is set to sweep through a plurality of frequencies in
accordance with the curve set forth in FIG. 5 that is depicted in
the table set just above, usually for a period of at least about 20
minutes and often from 20 to 30 minutes. It is noted that, either a
single frequency parameter sweep may be performed or at the end of
a first sweep, the treatment may be repeated at a next higher
intensity level.
[0075] Generally, when the method of treatment is employed to
create a nerve block by electroanesthesia, one may incrementally
decrease the stimulation frequency parameter for a time duration
(T) as exemplified in FIG. 5 by employing the following steps of
(a) continuously decreasing the stimulation frequency about 73% of
the first high frequency over the first time period 0.1T; (b)
continuously decreasing the stimulation frequency about another 8%
of the first high frequency over the next time period 0.1T; (c)
continuously decreasing the stimulation frequency about another 5%
of the first high frequency over the next time period 0.1T; (d)
continuously decreasing the stimulation frequency about another 4%
of the first high frequency over the next time period 0.1T; and (e)
continuously decreasing the stimulation frequency about another 10%
over the remaining time period of 0.6T.
[0076] As can be seen from the Figures herein, the frequency curves
have a similar basically logarithmic shape. Association of specific
frequency parameters and curve slopes with a specific disorder is
preferably determined by clinical evaluation. In fact, the
different curves exemplified herein are useful for treating other
diseases and disorders. Thus, it is the particular manner of
stimulating described herein that makes these methods particularly
effective, that is the stimulating manner of sweeping through the
same set of frequency parameters from a high frequency parameter
of, for example, 40,000 Hz, to a low frequency of, for example 400
Hz, at each of a plurality of incrementally increasing stimulation
intensities.
[0077] It is believed that the required initial stimulation at a
high frequency causes rapid depolarization of the cell permitting
ideal functioning of the so stimulated neurons. Whereas prior art
TENS devices and methods are believed to stimulate only the large
A.beta. fibers of the nervous system, it is believed that the
present method results in stimulation of the A.delta. and C fibers
as well as the A.beta. fibers, by providing stimulation waveforms
that closely mimic natural action potential waveforms and/or
piggyback on such waveforms. Increases in circulating blood levels
of various neurotransmitters, such as norepinephrine, serotonin,
epinephrine, ACTH and beta endorphins, provide evidence of this
mode of operation.
[0078] As seen in FIG. 6, in one patient, suffering with chronic
pain, the levels of various neurotransmitters not only increased
during the 20 minute treatment provided, but continued to
measurably increase for the 24 hours following such treatment. Note
that the y-axis scale on the graph in FIG. 6 is relativistic.
Levels of the neurotransmitters are measured in pg/ml for
epinephrine and norepinephrine, in pmol/l for ACTH, in ng/ml for
serotonin and in pg/0. 1 ml for beta endorphin. Thus, the graph
should be used to compare levels of a single neurotransmitter over
time not to compare levels among neurotransmitters. Thus, by
providing electrical stimulation at a central location on the body,
in accordance with the methods detailed herein, the body's natural
healing mechanisms are systemically stimulated to relieve the
symptoms of the nerve-related disease condition being treated.
[0079] The examples provided herein are of specific embodiments
only and are not intended to limit the scope of the claims appended
hereto. Those of skill in the art will recognize that the preferred
embodiments described herein may be altered or amended without
departing from the true spirit and scope of the invention, as
defined in the following claims.
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