| United States Patent |
4,503,863 |
| Katims |
* March 12, 1985 |
Method and apparatus for transcutaneous electrical stimulation
Abstract
A method and apparatus for monitoring and obtaining actual bio-electrical
characteristics of a subject under predetermined conditions of evoked response
stimuli, and by interaction with a computer, applying cutaneous electrical
stimulation to the subject, using a signal generator to modify current amplitude
and frequency in a direction to achieve bio-electrical characteristics in the
subject related to the actual bio-electrical characteristics monitored. The
signal generator uses a sinusoidal waveform output, with battery power passed
through a transformer to power a transconductance amplifier to obtain constant
current output despite resistance changes in the line with the subject, and with
the transformer not placed in the signal path of the sinusoidal waveform. The
signal may be obtained from a sinusoidal oscillator of wide frequency having
switched integrator sections connected to an inverting amplifier, pulse
generator and gating.
| Inventors: |
Katims; Jefferson J. (5813 Greenspring
Ave., Baltimore, MD 21209) |
| [*] Notice: |
The portion of the term of this patent
subsequent to December 15, 1998 has been disclaimed. |
| Appl. No.: |
302340 |
| Filed: |
September 15, 1981 |
| Current U.S. Class: |
600/554; 128/905; 600/26;
600/545; 607/54; 607/62; 607/64 |
| Intern'l Class: |
A61B 005/05; A61N 001/32 |
| Field of Search: |
128/1 C,731-734,741,419 R,420
R,421,422,423 R,905,791-793 |
References Cited
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Primary
Examiner: Cohen; Lee S.
Attorney, Agent or Firm: Flocks; Karl W.,
Neimark; Sheridan, Starobin; A. Fred
Parent Case Text
BACKGROUND OF THE INVENTION
This application is a
continuation-in-part of Ser. No. 053,568, filed 6/29/79, now U.S. Pat. No.
4,305,402 of Jefferson Jacob Katims, issued Dec. 15, 1981, and entitled "METHOD
AND APPARATUS FOR TRANSCUTANEOUS ELECTRICAL STIMULATION".
Claims
What is claimed is:
1. A method of diagnostic and therapeutic
treatment of a patient comprising the steps of applying a source of
electrical stimulation to the patient, applying alternating constant
current electrical stimulation from said source, controlling the current
and frequency of the stimulation within current parameters and through a range
of frequency parameters including low frequencies which initiate non-adversive
sensations.
2. The method diagnostic and therapeutic treatment of claim
1, further characterized by said alternating constant current electrical
stimulation being in the form of a continuous sine wave.
3. The method
of diagnostic and therapeutic treatment of claim 1 or 2, further characterized
by providing a unique individual profile or medical record of the
frequency versus threshhold current intensity at which the patient feels the
subjective sensation of electrical tingling where the electrical stimulation is
applied to the patient.
4. The method of diagnostic and therapeutic
treatment of claim 1 or 2, further charcterized by providing a unique
individual profile or medical record of the frequency versus threshhold current
intensity at which a monitoring means monitors the response evoked by the
electrical stimulation applied to the patient.
5. The method of
diagnostic and therapeutic treatment of claim 1 or 2, further characterized by
providing a unique individual profile or medical record of the frequency
versus current intensity at which the patient has a physiological state induced.
6. The method of diagnostic and therapeutic treatment of claim 1,
further characterized by said source of electrical stimulation being
applied at the head area of the patient.
7. The method of diagnostic and
therapeutic treatment of claim 6, further characterized by the steps of
controlling the frequency to a range within which the visual field of
the patient appears to be pulsating or oscillating, controlling the
frequency to a range within which the patient perceives a flickering pale white
light, conrolling the frequency to a range within which the patient
experiences a reasonance or vibratory sensation emanating from his head.
8. The method of diagnostic and therapeutic treatment of claim 7,
further characterized by controlling the frequency to a range between 5
to 19 hertz within which range there appears to the patient to be the distinct
sensation of a pulsating or oscillating visual field.
9. The method of
diagnostic and therapeutic treatment of claim 7, further characterized by
controlling the frequency to a range between 12 to 80 hertz within which
the patient perceives a distinct sensation of a flickering pale white light.
10. The method of diagnostic and therapeutic treatmen of claim 7,
further characterized by controlling the frequency to a range between 60
to 573 hertz within which the patient experiences a distinct resonating or
vibratory sensation emanating from his head.
11. The method of
diagnostic and therapeutic treatment of claim 7, 8, 9 or 10, further
characterized by providing a unique individual profile or medical
record, varying with the patient's state of health, of a patient's
electrophysiological state or sensations which are evoked in response to various
parameters of electrical stimulation.
12. Bio-electric stimulation
apparatus for diagnostic and therapeutic treatment of a patient comprising
a source of alternating constant current electrical stimulation
means to apply said source of electrical stimulation to the patient,
means to control and vary the current and frequency of the stimulation
within current parameters and through a range of frequency parameters determined
by subjective sensations experienced by the patient,
said source of
alternating constant current electrical stimulation being capable of variation
of frequency at least between 5 to 573 hertz.
13. The apparatus of claim
12, further characterized by means for connection to the patient to
obtain the bio-electrical characteristics of the patient at the current and
frequency parameter which initiate the non-adversive sensation which is
characterized as tingling.
14. The apparatus of claim 12, further
characterized by means for connected to the patient to obtain the
bio-electrical characteristics at discrete frequency ranges within which the
visual field of the patient appears to be pulsating or oscillating, within which
the patient perceives a flickering pale white light, and within which the
patient experiences a resonating or vibrating sensation emanating from his head.
15. The apparatus of claim 12, further characterized by said
control means including a single control to vary the frequency of said source
over its range of frequency at least between 5 to 573 hertz.
16. The
apparatus of claim 12, further characterized by said source of
alternating constant current electrical stimulation including a
sinusoidal oscillator of wide frequency range covering at least between 5 and
573 hertz.
17. Bio-electric stimulation apparatus for diagnostic and
therapeutic treatment of a patient comprising a source of alternating
current electrical stimulation, means to apply said source of electrical
stimulation to the patient, means to control the current and frequency
of the stimulation within current parameters and through a range of frequency
parameter including low frequencies determined by subjective sensations
experienced by the patient, means for connection to the patient to
obtain the bio-electrical characteristics of the patient at the current and
frequency parameters which initiate the non-adversive sensations.
18.
The apparatus of claim 17, further characterized by means to monitor the
actual bio-electrical characteristics of the patient connected to said means to
obtain such characteristics under predetermined conditions and means to
modify current and frequency connected to said control means and said monitor
means to achieve bio-electrical characteristics in the patient related to the
actual bio-electrical charcteristics monitored.
19. The apparatus of
claim 18, further characterized by the bio-electrical characteristics
being the psycho-electro-physiological state of the patient.
20. The
apparatus of claim 18, further characterized by said modifying means
including a computer means connected to said monitoring means and said source of
electrical stimulation to receive information from said monitoring means as to
the actual bio-electrical characteristics of the patient and to control said
source of stimulation applied to the patient in accordance with the receipt of
the information from said monitoring means.
21. The apparatus of claim
20, further characterized by means to apply evoked response stimuli by
psycho-physical interaction to the patient said means to apply stimuli
being connected to and responding to interaction with said computer means.
22. The apparatus of claim 17, further characterized by said
means to apply said source of electrical stimulation including a pair of
electrodes adapted for placement closely anterior of the earlobes of the
patient.
23. The apparatus of claim 17, further characterized by
said source of electrical stimulation including signal generator
means having constant current means to maintain a constant current output to the
patient at any setting of current amplitude and changes in circuit resistance in
connection with the patient.
24. The apparatus of claim 23, further
characterized by said constant current means including a
transconductance amplifier having an output to the patient.
25. The
apparatus of claim 23, further characterized by said means to apply said
source of electrical stimulation including a pair of electrodes adapted
for placement on the patient, said signal generator means including
a waveforming means, amplifier means connected in a signal path
from said waveforming means to said constant current means, said
amplifier means also being connected to one of said pair of electrodes and said
constant current means being connected to the other of said pair of electrodes.
26. The apparatus of claim 25, further characterized by said
signal generator means including a sensing resistor means to monitor the
output to the patient connected to ground from a connection from said amplifier
means and said electrode connected thereto.
27. The apparatus of claim
17, further characterized by said means for connection to the patient to
obtain the bio-electrical characteristics of the patient having a range of
operation to include ranges within which the visual field of the patient appears
to be pulsating or oscillating, within which the patient perceives a flickering
pale white light, and within which the patient experiences a resonating or
vibrating sensation emanating from his head.
Description
The present invention relates to bio-electric stimulators and more
particularly to stimulation by transcutaneous application of electricity as a
therapeutic tool.
In medicine the earliest known bio-electric
stimulators utilized for the direct application of electricity to the human skin
as a therapeutic tool appeared around 1750. The direct application of electrical
stimulation to human neuronal tissue or stimulation has also been in a
therapeutic use for the past 20 years.
Various therapeutic applications
of mild electric stimulation, in contrast to gross stimulation such as
electroconvulsive shock, directly applied to human skin has been purported to
include sleep induction or curing of insomnia, anesthesia, analgesia,
attenuation of withdrawal from drug addiction, relief from asthma, as well as
relief from anxiety and depression.
The therapeutic applications of
direct electrical stimulation to neural tissue or subcutaneous stimulation
includes induction of analgesia, alleviation of symptoms of multiple sclerosis,
cerebral palsy, epilepsy and spasticity, facilitation of the healing of
non-union bone fractures, cardiac and diaphragm pacemakers, as well as
electrical bladder control. Another application of electrical stimulation is in
the field of bio-research, primarily electrophysiology.
A widely used
diagnostic device used today in modern medical neurology is the pin. The
neurologist routinely employs the pin to scratch or prick a patient's skin to
test the integrity of the nerve fibers which innervate the cutaneous area being
stimulated. This type of diagnostic procedure provides critical information as
to whether a nerve fiber has been damaged by, for example, an industrial toxic
agent such as acrylate. There are many serious drawbacks to this diagnostic
procedure, including the following:
It is impossible to apply the pin to
the skin with an equal pressure to all skin regions being treated. This makes it
difficult for the neurologist to get a clear understanding of the patient's
response.
This diagnostic procedure is not quantitative.
The pin
can puncture or scratch the tissues being stimulated.
Among the first
nerve fibers to be damaged by acrylate are those which innervate the toes. Due
to the fact that several regions of the toes and feet are often unevenly
caloused, it is difficult for a neurologist to get a clear picture of possible
nerve damage in this area by the use of a pin.
SUMMARY OF THE INVENTION
It is an object of the present invention to be able to provide a unique
medical record of the brain's electrophysiological state and its response to
different frequencies and types of stimulation which is of great value in the
field of neurology. The present invention can also be utilized for the study of
intelligence and psychoneurological disorders.
Eventually, a doctor,
after completing a profile on a patient, utilizing the present invention, would
be able to prescribe machine settings in order to help the patient wake up, go
to sleep, replace drugs, play a song, or a game of pinball.
A further
advantage of the present invention is its use in the electrical stimulator of a
constant current output. The advantage of a constant current output is that it
automatically accounts and corrects for any fluctuations in electrical
resistance that may occur within the overall system. This would not be accounted
for by a constant voltage output. Constant current also provides a superior
margin of electrical safety in comparison with constant voltage where
fluctuations in electrical resistance can cause shocking to the subject. Changes
in resistance could be due to natural endogenous fluctuations in the resistance
of human tissue; i.e. perspiration, or exogenous resistance fluctuations caused
by the drying out of electrode paste used with the electrodes.
Another
advantage is use of constant current which resembles the natural current flow in
neuroelectrophysiology. Caution must be exercised if a constant voltage source
is applied instead of constant current since a person could serve as a
rectifying load thereby leaving a net charge on their self which would lead to
desensitization.
An additional safety feature of the present invention
is a clipping system used in the electrical stimulator.
It is a further
object of the present invention to establish a system for back and forth
interaction between an electrical stimulator and a control computer.
Another object of the present invention is to disclose a method and
apparatus which operates in response to an actual psycho-electrophysiological
state to modify current amplitude and frequency in a direction to achieve the
desired such state. In a more limited aspect, in response to an actual EEG, to
modify amplitude of current and frequency in a direction to achieve a desired
EEG.
Further, it is an object to achieve such state by cutaneous
electrical stimulation.
Also it is an object to obtain therapy for the
subject by producing altered subjective electrophysiological states in the
subject. Value of the present invention is shown in the relief of subjective
physiological distress associated with disease as well as creating a favorable
subjective physiological state in the normal subject.
Also, it is a
further object of this invention to avoid the problems associated with the
diagnostic procedue which employs a pin. These problems can be avoided by the
application of cutaneous electrical stimulation for the following reasons:
The pressure with which the cutaneous electrical stimulation is
administered is not a factor of its diagnostic efficacy. What is being measured
with cutaneous electrical stimulation is the threshold of the current intensity
required to evoke a tingling sensation at the electrode site. The pressure with
which the electrodes touch the skin does not affect the current threshold.
This cutaneous electrical stimulation diagnostic procedure is
quantitative in that the current threshold value numbers can be recorded in the
medical record and used for future comparison.
A further advantage of
this technique is its neuronal frequency specificity. At different frequencies
of stimulation different nerve fibers are stimulated which have different
current thresholds for the cutaneous tingling sensation. This cutaneous
electrical stimulation procedure has the advantage of providing the neurologist
with the cutaneous threshold values for several different nerve populations at
the same cutaneous location by the application of various frequencies, thus
providing more information than the solitary non-quantitative cutaneous
threshold obtained with a pin.
The cutaneous electrical stimulation
diagnostic technique is not dangerous to the tissues being stimulated.
The cutaneous electrical stimulation diagnostic technique is not
affected by calouses at the cutaneous sites being stimulated.
BRIEF
DESCRIPTION OF THE DRAWING
The invention can best be understood by
referring to the accompanying drawings in which:
FIG. 1 is an
illustration of the system of the present invention connected to a subject;
FIG. 2 is a block diagram illustration of the overall system;
FIG. 3 is an enlarged view of the front panel of a signal generator used
in the system;
FIG. 4 is an enlarged view of the front panel of the
electrical stimulator used in the system;
FIG. 5 is a block-schematic
diagram of the signal generator and electrical stimulator of FIGS. 3 and 4,
respectively;
FIG. 6 is a graph showing frequency outputs for the knob
settings of the signal generator of FIG. 3;
FIG. 7 is a graph showing
frequency band outputs for knob settings of the electrical stimulator of FIG. 4;
FIG. 8 is a graph of the current output level of the electrical
stimulator of FIG. 4 with respect to amplitude control knob settings;
FIG. 9 is a block diagram of another embodiment of a sinusoidal
oscillator used in place of the signal generator and a portion of the electrical
stimulator of FIG. 5;
FIG. 10 is a more detailed illustration of
circuitry of the embodiment of FIG. 9.
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
First the theoretical basis of the present invention is
discussed in terms of its output wave shape, frequency coding and physiology, as
well as human neuroanatomy, neurochemistry, and neuropsychology.
A
sinusoidal wave shape is the choice for use in the present invention based upon
the desire to minimize the amplitude of the stimulating current and the
observation by the present inventor that a sinusoidal wave shape is
approximately 15 times more effective than a square wave in affecting the
physiologial state of mammalian neuronal tissue. 1 pilot study performed in
conjunction with studies for the present invention showed unpleasant subjective
side effects for a square wave form and none such side effects for a sinusoidal
wave form. A further convenience of the sinusoid is its simple frequency domain
representation.
The frequency coding of individual neurons for both
communication and in response to electrical stimulation, as well as the ability
to induce electrocortical activity; e.g., recruitment of EEG, are well
established facts in neuroscience. The frequency coding phenomenon may have to
do with the temporal summation of the excitatory effect of a neurotransmitter at
the synapse between neurons, or endogenous electrical time constants of neuronal
membrances which are independent of neurotransmitters. It is the intent of the
electrical stimulator in the present invention to try to excite endogenous
rhythms within the brain as well as to stimulate particular brain regions to
produce a psychotherapeutic affect. The frequency coding properties of a human's
brain subjective psychological states in response to cutaneous application of
this stimulator are demonstratable by experiments of the present invention.
By placing two electrodes on a human subject's skin over the jawbone in
front of each earlobe and passing a current between them, there is created an
electron flow of which approximately 95% passes through the face and 5% passes
through the cranium. This 5% has been demonstrated to be capable of inducing
slight fluctuations in brain electrical potentials for the duration of the
stimulation in humans. These fluctuations could account for one of the ways in
which the machine used in the present invention could induce electrocortical
activity; the other possible type of electrocortical induction is discussed
later in dealing with the nucleus of the reticular formation.
The 95% of
the current flow passing through the face is capable of directly inducing
fluctuations in the resting membrane potentials of the nerve fibers innervating
the face and the entire underlying musculature. The sensory and motor fibers
being stimulated primarily involve the fifth (V) cranial nerve, the trigeminal.
Other cranial nerve fibers are stimulated as well including nerves VII, X, XI
and XII. The primary locus of the theoretical basis of the mechanism of action
of the machine in the present invention concerns the trigeninal nerve. The cell
bodies of its primary sensory fibers are located deep within the midbrain in the
trigeminal nucleus. These cell bodies are the only unencapsulated primary
sensory neurons within the central nervous system. It is the intent of the
stimulator of the present invention, by the method of the present invention, to
selectively stimulate these neurons with different frequencies of electrical
stimulation, in effect to affect their activity and the activity of associated
neurons in other brain stem nuclei. Through this process one is able to induce
neuroelectrical and endogenous neurochemical changes in the human brain state.
Stimulation of the trigeminal nucleus and its sensory fibers as well as
classical acupuncture has been demonstrated to be capable of inducing
electrocortical activity. Both the putative neurotransmitters, Substance P and
Enkephalin, have been found in neurons within this nucleus. Both of these
putative neurotransmitters have been postulated to be involved with limbic
emotional brain functions. It should be mentioned here that the Enkaphalins have
been demonstrated to be our own endogenous opiate-like substance. Both the
antidepressants and the tranquilizers are drugs which exert an influence on this
nucleus with the brain.
The following brain stem nuclei mentioned all
have intimate neuronal connections with the trigeminal nucleus.
The
nucleus ambiguus contains some of the cell bodies of cranial nerves IX, X and
IX. The auricular branch of the vagus nerve (X) enters the trigeminal nucleus
from the nucleus ambiguus. The fibers from the vagus nerve (X) provide primary
central sensory and motor innervations of the heart, lungs, and the
gastrointestinal tract.
The primary role of the nucleus of the reticular
formation is in the regulation of all types of electrocortical activity.
The portion of the reticular formation comprising the nucleus
gigantocellularis within the pontine tegmentum has been found to be essential
for dreaming to occur. The nucleus gigantocellularis has also been demonstrated
to have intimate neurochemical associations with the trigeminal nucleus.
The central gray region contains among the densest concentration of
Enkephalins within the brain; if stimulated electrically it will induce
analgesia in humans.
The neurons within the raphae nuclei utilize the
neurotransmitter serotonin which is involved in the fundamental regulation of
the sleep-wakefulness cycle and is a system which is affected by psychedelic
drugs.
The locus coeruleui, blue in their natural state within the
brain, contain cell bodies which are adjacent to cell bodies of the trigeminal
nucleus. This close anatomical relationship would facilitate an electrotonic
interaction between these two groups of cell bodies. The locus coeruleus is one
of the primary sources of the noradrenergic neurotransmitter system within the
human brain. This system is involved with learning and memory, depression and
pleasure, and certain psychotic disorders. It is affected by drugs such as
cocaine and heroin.
The vestibular nucleus is involved with our sense of
balance as well as nausea.
The inferior and superior colliculi are
associated with a primitive body, space, auditory, and visual sense system.
The cerebellum portion of our brain represent a primitive motor cortex
and plays a role in complex timing functions, learning and memory, and execution
of complex motor tasks.
The present invention is concerned with the
above theoretical basis but it is from investigations by the inventor that the
method and apparatus of the invention has evolved.
FIGS. 1 and 2 show
the over-all system. The signal generator electrical apparatus 10 is composed of
a triple output signal generator 11 and electrical stimulator 12 interfaced to
be under control of computer 13. Although signal generator 11 and electrical
stimulator 12 are shown in the illustrated embodiment of FIGS. 1 and 2; as many
generators as necessary may be utilized or electrical stimulator 12 may be used
alone. Outputs from apparatus 10 go to the subject S and to computer 13.
Evoked response system 15 may be any audio, visual, tactile, or
situational stimuli whatsoever and this system is also interfaced with computer
13.
Examples of evoked-response stimuli are:
1. Audio stimuli
such as any good commercial music synthesizer which can be interfaced to
computer 13. A well interfaced and controlled sound reproduction system is also
desired.
2. Visual stimuli such as any standard video camera and monitor
system in closed circuit television. A video synthesizer would also be included
in this system.
3. Tactile stimuli which could include such things as a
solenoid or piezoelectric activated skin stimulator, an electrical vibrator,
such as the type used for massage, or bone conduction hearing aids.
4.
Psychological stimuli which concern the conditions under which the subject is
being treated. This could be programmed into computer 13.
Monitoring
system 17 which is also interfaced with computer 13 and receives outputs from
subjects, is composed of three sub-systems (not shown). These sub-systems are:
1. A transducer system which receives inputs from any
electrophysiological parameter which may be monitored from the subject; e.g.,
electrocardiogram (EKG), electromyelogram (EMG), galvanized skin resistance
(GSR), electro-oculogram (EOG), blood pressure, breathing, etc. This system also
utilizes a video camera, microphone, or electric light pencil as a type of
input.
2. A preprocessing signal conditioning system which receives
input from the transducer system and is interfaced such that it may be
computer-controlled. This serves to provide a usable signal for the computer 13
and signal analysis (see following) systems. This system sends outputs to
computer 13 and the signal analysis system. This system consists of
preamplifiers, amplifiers, band pass amplifiers, etc.
3. A signal
analysis system to perform real time analysis of the incoming data for the
controlling computer 13. Examples of types of signal analysis performed include
statistical temporal correlation, photo accoustic spectroscopy, EEG filtering
techniques, Fourier analysis, and other forms of linear and non-linear signal
analysis. Many components of this system could be incorporated into computer 13.
Monitoring here is done at the subject leads instead of at the primary
side of the transformer in order to better account for variable impedances at
the subject such as at the electrodes.
Computer 13 is a high-speed
digital type of computer, capable of performing statistical correlative analysis
and possessing a large amount of memory circuitry. Computer 13 is fully
interfaced with the signal generator electrical system 10, the evoked response
system 15, the preprocessing signal conditioning system and the signal analysis
system, both described above as parts of monitoring system 17.
The
function of computer 13 is to interactively simulate the subject S with the
signal generating system 10 and the evoked response system 15 and monitor and
analyze the data from the monitoring system 17 to induce a particular electrical
or subjective state.
Computer 13 analyzes the EEG from output obtained
via the signal analysis system in terms of evoked potentials, event-related
potentials, pre- or post-stimulus potentials of an extremely long or short
duration, habituation or dishabituation of evoked response, synchronization of
output, fluctuations in negative or positive pre- or post-stimulus potentials,
and recruitment of EEG frequencies with respect to frequencies of stimulation.
Computer 13 is then programmed to correlate the EEG analysis data with the
chemical, physiological and psychological state of the subject S.
The
chemical state refers to whether the subject is under the influence or addicted
to any drugs. the physiological state refers to any electrophysiological
parameters being monitored by the computer. The psychological state refers to
the subjective or objective psychological state and the state of attention of
the subject, as well as psychological profiles of, say, a movie being observed
(e.g., male vs. female characters) or performance in a pinball game (e.g., a hit
vs. a miss).
Computer 13 will continually interface or mediate a two-way
interaction between the subject's psychoelectrophysiological state and the
stimuli to which the subject is being exposed or with which the subject is
interacting. This application of computer 13 can be under control of either the
subject or the observer.
For example, computer 13 can be programmed to
automatically be able to compare and contrast different combinations and
permutations of different frequencies of cutaneous electrical stimulation to
determine which has the most efficient output in evoking the recruitment of
synchronization of EEG activity. The latter is associated with a pleasurable or
sedated state of consciousness. Computer 13 may modulate the evoked response
system 15 as well, to achieve the same effect.
By comparing the
components of electrocortical pre- post stimulus potentials evoked response and
utilizing amplitude discrimination and monitoring the sequential frequency over
time, computer 13 is able to modulate cutaneous current levels and frequencies
utilizing the signal generator electrical stimulator system to prevent
habituation or desenitization of the subject's electrophysiological state. This
is a method by which computer 13 quantitatively maintains tingling subjective
levels of electrical current.
Biofeedback parameters such as blood
pressure, electrocardiogram, or breathing, which are monitored by the transducer
system of monitoring system 17, may be analyzed by computer 13 and can be
systematically correlated with the frequency dimension of the cutaneous
electrical stimulation. Computer 13 can systematically evoke different
frequencies of cutaneous stimulation to modulate cardiovascular or pulmonary
rates to desired therapeutic levels.
For example, in therapeutic
applications, while listening to a song, certain notes or patterns in the rhythm
are correlated by computer 13 with the subject's electrophysiological state.
Computer 13 can either accentuate the stimulus (in this case by affecting either
the volume or timing of the music through the evoked response system 15), or the
brain's electrical state (utilizing signal generator electrical stimulator
system 10), or both in order to heighten the subject's awareness of both. This
same logic may be applied towards a game of pinball, or a movie, any type of
stimulus which may be applied therapeutically, or to maintain a high state of
attentiveness in a subject for performance of a complex task.
Signal
generator 11 is shown as connected to computer 13 and is a triple output signal
generator used to send a large range of frequencies and combinations of these
frequencies, through electrical stimulator 12 to a pair of electrodes 18 placed
on the skin of subject's approximately 1/4 inch anterior to each earlobe. The
electrodes 18 may be dime electrodes, made in size, shape, and material similar
to that coin. Although signal generator 11 is illustrated here, it is possible
to practice the present invention with only electrical stimulator 12 of signal
generator electrical stimulator apparatus 10, but at a sacrifice in general
useful range. As illustrated in the enlarged view of its front panel in FIG. 3
and one portion of the block-schematic diagram of FIG. 5, signal generator 11 is
composed of three waveform generators 21A, 21B, 21C, each with its frequency
control 22A, 22B and 22C, respectively and its bandswitch control 23A, 23B and
23C, respectively. Power is supplied to the waveform generators 21A, 21B, 21C
through power charge switch 24 from two 6-volt batteries connected in series for
a 12-volt power supply (rechargeable as two 6-volt batteries in parallel). A
battery low indicator 25 shown here as a light which indicates a need to
recharge batteries is connected to power charge switch 24. Current output
controls 26A, 26B, 26C from each of the waveform generators 21A, 21B, 21C,
respectively, are illustrated as potentiometers 26A', 26B', 26C' and are
connected to output terminal 29 through inverting amplifier 27 and master
current control 28, noted as potentiometer 28'. A power switch and power-on
indicator light are also shown for their normal purposes. All ground connections
for signal generator 11 and electrical stimulator 12 are connected as a common
ground.
Each of the frequency bandswitch controls 23A, 23B, 23C have
bandswitch positions A, B, and C designated with A designating the low frequency
band, B designating a medium frequency band, and C designating a high frequency
band. The frequency output for the knob settings on each of frequency controls
22A, 22B, 22C in each of the three bands A, B, and C is shown on the graph of
FIG. 6. The three curves thereon designate the frequency in hertz for the knob
settings on the particular signal generator used but this can be worked out for
other signal generators which preferably will operate in the same ranges. For
the particular signal generator used, the master control 28 regulated the
over-all current output with a 10 mA maximum output current from amplifier 27.
Each of waveform generators 21A, 21B, 21C in the preamplifier had a 1.3 V peak
signal. This signal generator's amplifier had a 10 mA/V transfer function with
the amplifier's level control at the full clockwise position.
The
amplitude controls on the signal generator were calibrated within 5%. The
individual level controls may be viewed as weighing factors and the master
control as an over-all multiplier. The signals add in quadrature, i.e.:
Peak output voltage (V)=A.sub.0 (A.sub.1.sup.2 +A.sub.2.sup.2
+A.sub.3.sup.2).sup.1/2 (1.3)
where A.sub.0 is the setting of the master
level control.
A.sub.1, A.sub.2, and A.sub.3 are the settings of the
individual level controls.
1.3 V is the peak output of the device.
It should be noted that the controls as illustrated read ten times the
actual level (i.e., 0 to 10 instead of 0 to 1).
The particular signal
generator specifications are to clearly illustrate a working embodiment but
should not be construed as absolute limits since other signal generators that
can be operated in these frequency ranges with similar output waveforms,
particularly sinusoidal waveforms, can be used. Also the use of a triple output
signal generator illustrated allows a wider range of results but the output of
simulator 12 alone is sufficient for some more limited purposes.
Signal
generator output terminal 29 is connected to electrical stimulator 12 as shown
in FIG. 5, mainly utilizing amplifier characteristics of electrical stimulator
12 by passing the signal from terminal 29 through currrent amplitude control
potentiometer 31', input amplifier 32, and output transconductance amplifier 33
to electrodes 18 contacting the subject S. Transconductance amplifier 33
maintains the constant current output despite fluctuations in the load.
Referring to FIG. 4, the front panel of electrical stimulator 12 has a
frequency control 34, current output control 35, frequency band switch 36, with
clipping indicator lights 37, battery low indicator light 38 and a pilot light
with the on-off switch with capabilities of a single output instead of the
triple output of signal generator 11.
Referring to the block-schematic
of FIG. 5, electrical stimulator 12 has a 6-volt battery supply. To this is
connected battery low comparator 38', used in conjunction with a diode reference
(not shown), and relaxation oscillator 41. Most any DC input can be used but the
battery connection illustrated is preferred. From relaxation oscillator 41 a
square wave output is buffered by inverting buffer 42, and non-inverting buffer
43 with their complementary outputs driving a pair of power transistors 44 which
chop the 6-volt battery voltage at a rate of several kilohertz and drive step-up
transformer 45. The induced voltage in the primary is full wave rectified to
provide +10 volt supply 46. The secondary drives a full wave doubler circuit
that provides .+-.50 volt supply 47.
Transformer 45 is used to match a
high impedance load (the subject) and simple, safe, low-voltage circuitry
without having the transformer in the signal path. In other machines of the type
for electrical stimulation that use transformers, the fact that the transformer
is in the signal path implies that all sorts of distortions that are inherent to
the transformer such as frequency limiting effects and the fact that no DC
current may pass through a transformer will interfere with the signal output
from these other simulators.
In the machine of the present invention,
the transformer is run at the optimal frequency and only as a power supply in
order to produce the high voltage output and rectify it back to DC. Therefore,
in this circuit a low-voltage battery has been transformed into a high-voltage
battery which powers a high-voltage circuit, namely the transconductance
amplifier 33 which puts out a constant current independent of load impedance.
Because it has been shown that sensation is proportional to current and not to
power, this type of constant current output prevents any problems concerning
changing resistance of skin or electrode paste on neuron resting membrane
potential. Therefore, in this machine nothing inherently limits the bandwidth
within the circuit.
The 10 V supply 46 powers waveform generator 48. The
frequency is set by 3 hand-switched capacitors 36' and the frequency control 34
potentiometer. Sine, sawtooth, and square wave outputs are provided but the
present invention uses the sine wave output. Due to the different levels and
output impedences of the outputs, compensating resistor networks 49 are
included. The .+-.50 V supply 47 supplies power to high compliance
transconductance amplifier 33. A .+-.15 V supply is provided by a zener
regulated supply for operation of input amplifier 32 which drives
transconductance output stage amplifier 33.
The load is driven in a
floating configuration with the current sensed across at 100 Ohm resistor 51
which provides a 10 mA/V transfer function.
Sense resistor 51 is used
since monitoring is done at the subject leads and not on the primary side of
variable loss transformer 45.
The setting for the frequency output on
each of bands A, B, and C for the knob settings on frequency control 34 is shown
on the graph of FIG. 7. The current output level for the knob settings on
current output control 35 is shown on the graph of FIG. 8. These figures give a
basis for frequency ranges and current levels used in the present invention.
An example of operation of apparatus of the present invention which
demonstrates the frequency coded properties of human subjective psychological
brain states as evoked by cutaneous electrical stimulation is as follows.
The subject should sit or lie down, relaxed, in a quiet room without any
loud auditory or visual distractions. Dime electrodes 18 are placed
approximately 1/4 inch anterior to each earlobe with electrode paste placed
between the skin and each electrode to serve as a conducting medium. The
electrodes 18 may be held in a place by the use of standard athletic headband as
shown. The current setting on the stimulator 12 is increased until a tingling
sensation is felt at the electrodes. The initial frequency of stimulation may be
randomly set.
Sufficient current must be emitted at the electrodes at
all times so that a subjective nonadversive sensation which patients
characterize as a slight tingling be felt at the electrodes. Any loss in the
tingling sensation at the electrodes may require an adjustment of current
intensity in order to continue to evoke the slight tingling sensation. The
subjective sensation of cutaneous electrical stimulation is a function of the
current, the frequency of the stimulation, both adjusted by electrical
stimulator 12 (or signal generator 11), and the state of relaxation of the
subject S.
In obtaining a profile of an individual subject adjustments
of apparatus are made based on verbal feedback from the subject. The frequency
output is adjusted to maintain the "slight tingling sensation" at electrodes 18.
The subject reports any unusual auditory, visual, sensual vibration, or other
sensation experienced. The subject may control stimulator 12 himself to effect
various frequency sensitive subjective psychological states. Frequency outputs
of stimulator 12 may also be adjusted without the subject's knowledge to collect
further data.
Alternatively because of monitoring system 17 effects of
the stimulation are obtainable even if the subject is unconscious and electrical
stimulation can be applied without verbal feedback from the subject.
As
stated previously, other signal generation means can be used with the present
invention to produce a sinusoidal oscillation. Such an oscillator which has
unique advantages of a very wide frequency range with a single control, low
power, low distortion, stable low frequency performance without large value
resistors and capacitors, and low cost is described in FIGS. 9 and 10. FIG. 9
shows the oscillator in block form while FIG. 10 shows the same oscillator with
logic circuitry.
Such sinusoidal oscillator of FIGS. 9 and 10 would
substitute in FIG. 5 for signal generator 11 and for waveform generator 48.
Since only 4 to 6 volts is required to supply this substituted oscillator, the
10-volt supply 46 may be changed to a 4 to 6-volt supply. The oscillator would
then be substituted with advantages enumerated above and following.
Prior design for sinusoidal oscillators of the R-C type (Wien Bridge,
R-C phase shift, twin-tee) do not allow wide adjustment range with a single
control. All of the standard RC sinusoidal oscillators require simultaneous
adjustment of at least two controls to achieve even 10:1 range. The design of
FIGS. 9 and 10 provides greater than 1000:1 range with a single control. Another
common type of sinusoidal oscillator is the LC type, Both the RC and LC types
share the disadvantages of limited adjustment range and are not practical at low
frequencies. Prior design sinusoidal oscillators that can approach the wide
adjustment range of the oscillator of the present invention are the clipped
triangle wave function generators which have inherent poor distortion
characteristics or the type that rely on heterodyne mixing of two high frequency
sinusoids. This variety has very poor frequency stability at low output
frequency. A new technique is shown in FIG. 9. Only three switched integrator
sections, each having an analog switch 61, a resistor 62 and a capacitor 63 are
shown. Three is the minimum number, although preferably more can be used which
lowers the distortion from the amplifier 64 and the gain control 65. The
amplifier 64 has an inverting minimum gain of .vertline.1/(jw.sub.o
RC+1).vertline..sup.n where j.perspectiveto..sqroot.-1, R=total of resistor and
switch resistance, C=total of switch capacitance to ground and capacitor,
n=number of stages, and W.sub.o =the natural frequency of the oscillator where
the switches are left on. Gain control 65 can be as simple as allowing the
amplifier 64 to clip (saturate) or any of the more refined techniques known. The
analog switches 61 are any of the many known analog switches in the field, such
as, for example, Model CMOS 4016, which is manufactured by several companies
such as RCA and Motorola Corporation. Likewise monostable, flip-flop 66 which
has an output signal which operates analog switches 61 is any of the common
monostable designs in the field. The pulse generator 67 may also be any common
technique of producing a wide frequency range pulse output. Wide range pulse
generator 67, through monostable flip-flop 66 supplies the signal at the
adjusted repetition rate of adjustment 68 to operate analog switches 61 which
control the output at 69 through amplifier 64.
The function of the
circuit is simply understood if it is realized that the circuit functions as a
normal RC phase shift oscillator when the switches are closed (much less time
than a normal cycle of the oscillator would require) and that the circuit holds
its output constant while the switches are open. Thus the output frequncy is at
f.sub.o /D where f.sub.o is the natural frquency of the RC oscillator and D is
the duty cycle of the signal during the time that the analog switches operate.
The use of a constant pulse width with repetition rate modulation
adjustment places the switching frequency at a constant multiple of the output
frequency (a fixed number of steps in the output wave-form). A constant
repetition rate with a variable duty cycle could also be used which results in a
constant switching frequency but this results in a variable number of steps in
the output wave-form with the minimum number of steps at the maximum output
frequency. This makes it more difficult to achieve a wide output frequency range
when faced with minimum pulse width considerations. The form of the circuit used
in such a device is shown in FIG. 2.
In FIG. 10 analog switches 61 are
associated with their respective resistors 62 and capacitors 63 to form switched
integrator sections with a signal from logic gates 76 operating analog switches
61. A form of wide range pulse generator circuit 77 with frequency adjustment 78
feeds the pulses at adjusted frequency to gates 76. Amplifier 64 in series with
the switched integrator sections conducts the signal to output 69 from whence
output is fed through the stimulator apparatus which connects with the subject.
For further experimental purposes, it is possible that a square wave or
sawtooth wave, besides the sinusoidal wave, might be required. The oscillator of
FIGS. 9 and 10 has this versatility as shown in FIG. 10 where a sawtooth output
may be picked off at point 81 and a parabolic wave at point 82. A square wave
output may be picked up from the output of amplifier 64. The sine wave output is
picked off at output 69.
Within the range of the equipment of the
present invention several distinct frequency sensitive subjective psychological
states may be observed in the subject.
Between the frequency range of 5
and 19 hertz subjects reported that their visual field appeared to be pulsating
or oscillating. This was not accompanied by any apparent movement of the
eyeballs.
At the next higher frequency of stimulation, from 12 Hz to 80
Hz, subjects reported a flickering pale white light, usually in the periphery of
their visual fields which got faster with increasing frequencies of stimulation
and eventually disappeared at approximately 80 Hz.
At 60 Hz to 573 Hz
frequencies, subjects reported the feeling of a unique sensation of a relaxing
hum, buzz, or vibration resonating from deep within their heads. In most cases
this sensation peaks at 70 Hz.
The above ranges of frequencies within
which the distinct subjective psychological states were described, were evoked
in healthy subjects by constant alternating current sinusoidal waveform
electrical stimulation transcutaneously applied to the head area.
When
this type of stimulation is similarly applied to unhealthy subjects, the profile
obtained of the parameters of the stimulation for evoked sensations is markedly
different from the profiles obtained from the healthy subjects.
For
example a narcotic addict presented a profile of the current threshhold for the
evocation of the cutaneous tingling sensation approximately four times greater
than a healthy subject. The narcotic addicts tested only were able to report a
resonance sensation with the sinusoidal waveform of stimulation without the
flickering or oscillation of visual field perception that was reported by
healthy subjects at corresponding frequencies. This profile of the addict is one
example of the type of information that the medical practitioner can obtain by
this diagnostic procedure.
In further studies of the diagnostic
procedure for obtaining a subject's profile of the frequency verses threshhold
current intensity for the subjective sensation of cutaneous electrical tingling
at the electrode sites it was found that the tingling sensation only may be
evoked by electrodes placed at any area of the body and is not limited to the
head area (as is the case for the other sensations described). In addition, it
was found that for this form of cutaneous tingling sensation diagnostic profile
procedure the waveform of electrical stimulation is not necessarily limited to a
sinusoid.
The described sensations may be evoked by using a biphasic
square wave stimulus but in such case the resolution of narrow frequency bands
for a particular sensation is not present. With the square wave, these
sensations are reported to occur together over a broad range of frequencies. For
example, the flickering light sensation as well as the resonance sensation are
reported as occurring together in the frequencies where only a flickering
sensation is reported alone when a sine waveform is used. Furthermore, when a
pulsed waveform such a 0.2 .mu.sec. biphasic pulse is used, neither a flickering
sensation nor an oscillation of visual field sensation is reported. Instead,
with this pulsed stimulus, there is the report of experiencing a resonance
sensation over a broad range of frequencies. Thus, for purposes of the present
invention, a sinusoidal waveform is used.
When more than one frequency
is applied such as when using triple output signal generator 11 in the system,
psychological states corresponding with the several frequencies or sum and
different frequencies will be experienced.
The present invention is used
to induce different psychological states but due to the apparatus of this
invention such states can be reached more quickly and with less current, thus
reducing the danger from such currents to the subject.
The present
invention has numerous practical applications dependent on attainment of these
psychological states and controlled maintaining of such a state.
The
subject first performs an act or is subjected to evoked response system 15. Such
evoked response could include listening to certain sounds, seeing certain
pictures, stimulation of the skin, subjection to a particular environment, or
taking of a drug, such as by an addict. The monitoring system 17 receives
electro-physiological parameters monitored from the subject and feeds this
information to computer 13. Using this information, the electrical parameters of
stimulation by the signal generator electrical stimulator apparatus 10 to
electrically mimic the effects of the evoked response system in the subject can
be determined. Computer 13 can be connected to control stimulation apparatus 10
to vary in accordance with maintaining a particular state based on information
being received from monitoring system 17.
An important aspect of such a
system is that by cutaneous electrical stimulation to produce particular
psychological states, the need of the original evoked response system may be
then eliminated and the subject may then be subjected or brought to the desired
psychological state without repeating of the evoked response system which system
as originally applied to the subject, may have deleterious effects on the
subject. One such case may be in respect to additive drugs where their effect on
the body may be simulated by cutaneous electrical stimulation at the point where
the electrodes 18 of the present invention are placed on the subject. Such
electrical stimulation being possible of close control may help in overcoming
withdrawal symptoms without the use of the deleterious drug. Concomitantly with
the cutaneous electrical stimulation for attenuation of withdrawal symptoms the
subject may self-administer nitrous oxide gas (N.sub.2 O) (or a similar type
cognitive activator) at physiological concentrations of approximately 60%
N.sub.2 O and 40% oxygen where conscious awareness is maintained. Such
self-administration of N.sub.2 O is to facilitate the formation of neuronal
connections and the consolidation of the memory of the experience and should
lessen the time needed for withdrawal than use of cutaneous stimulation alone.
This process will serve to permit the former drug addicts to have conscious
awareness of their natural electro-cotical and electro chemical state which they
had been artificially inducing with the drugs. By sensitizing these natural
systems within the brain through the use of cutaneous electrical stimulation,
this process will induce an antibuse type of physiological state in the event of
further drug use. Since the effects of cutaneous electrical stimulation involve
primarily regions of the brain involved with non-verbal conscious stages of
awareness, this therapy should include psychotherapy to bring to the subject's
conscious awareness, through verbal communication, the effects of the electrical
stimulation being administered. This may be done by electronically inducing a
hypnotic state of awareness in the subject at which time a trained
psychotherapist can explain to the subject that future self-administration of
the drug is not necessary. If the desire for the drug again should occur, this
desire can be relieved by the electrical stimulator which would reduce the
physiological craving for the drug as well as evoking a psychoelectrical
stimulus which is associated with a psychological state in which the drug is
unnecessary.
Other uses may be made of the apparatus of the present
invention and the method of the present invention may be applied to obtain other
therapeutic results.
The words "cutaneous" and "cutaneously" to be
correctly interpreted as to where electrical stimulation may be applied in the
present invention includes the application of electrical stimulation on surfaces
of the body even where such surfaces may extend into orifices of the body.
It will be obvious to those skilled in the art that various changes may
be made without departing from the scope of the invention and the invention is
not to be considered limited to what is shown in the drawings and described in
the specification.
* * * * *