Patent No. 4305402 Method for transcutaneous electrical stimulation
Patent No. 4305402 Method for transcutaneous electrical stimulation (Katims, Dec 15, 1981)
Abstract
A method and apparatus for monitoring and obtaining actual bio-electrical characteristics of a subject, such as EEG, or determinants of the psycho-electro-physiological state of the subject, under predetermined conditions of evoked response stimuli, and by interaction with a computer, apply 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 may have an output of several frequencies simultaneously, and 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.
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BACKGROUND
OF THE INVENTION
The present invention relates to bio-electric stimulators utilized and more
particularly to stimulation by transcutaneous application of electricity as
a therapeutic tool.
In medicine the earliest known bio-electric stimulators 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, allevation 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.
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 over-all 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 neuro-electrophysiology. 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-electro-physiological 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 electro-physiological 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.
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