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Patent No. 3850161
Method and apparatus for monitoring and counteracting excess brain electrical
energy to prevent epileptic seizures and the like (Liss, Nov 26, 1974)
Abstract
This invention pertains to a biomedical detecting and control apparatus wherein electrical signals in the brain of mammals are continuously monitored by electrodes implanted in certain critical places in the brain wherein excess electrical energy is manifest during epileptic seizure conditions as well as during psychic storms of some types of mental illness. Such signals are processed via electrical systems of various circuits for inversion, comparison, vector analog addition, filtering, modulation, level set, safety level limits and self test to provide a controlled signal output which automatically reduces or eliminates the excess electrical energy at the point of detection. The points of detection and control may be, but do not have to be, the same spots on the brain. The probes may be near the surface of the brain or deep set in the brain depending upon the area affected. In addition to the method, there is described an electronic device which is contemplated to be housed in a small housing outside the body of the mammal and connected through wire conductors connected to the electrodes at the point of detection and at the other end of the conductors to outlet connectors in the housing providing the point of control.
Notes:
BACKGROUND
OF THE INVENTION
1. Field of the Invention
With reference to the classification of art as established in the U.S. Patent
Office the present invention pertains to art found in the Class entitled, "Surgery"
(Class 128) and the subclass of "pulsating and alternating electric circuits"
(subclass 421).
2. Description of the Prior Art
Many patents are directed toward analysis of and conditions causing mental illness.
These studies of mammal brains and the resulting behaviors have confirmed that
electrical impulses within the brain cause predicted results in parts of the
body associated with specific areas of the brain. Among these patents are U.S.
Pat. No. 3,495,596 to CONDICT as issued on Feb. 17, 1970; U.S. Pat. No. 2,368,207
to EATON as issued on Jan. 30, 1945 and U.S. Pat. No. 2,473,378 to LIBERSON
as issued on June 14, 1949.
As a result of these studies of mammals, including humans, it has been found
that there are certain types of epilepsy and psychic diseases (mental illness)
wherein an aura condition exists prior to the happening of an epileptic or psychic
storm. During that period of time it has been found that the level of electrical
activity rises by a magnitude of 5 to 10 times the normal 10 millivolt level
typically found in the average human brain. The frequency of the brain signals
change from 5 to 8 herz down to one-half to one herz. During this storm period
in particular areas of the brain, the pattern of electrical activity or irregularity
can spread to other various spots and areas of the brain much in the way worn
electrical insulation may give way to excess electrical potential causing an
electrical discharge either locally or in large areas depending on the specific
characteristics of insulation and voltage application. Just as electrical systems
of extreme precision are protected and controlled by regulators, filters, fuses,
etc. so also is it a purpose of this device to counteract automatically any
excess electrical energy in the brain at the spots being monitored and detected.
Cases have been reported wherein olfactory senses have been utilized to overcome
the aura effect and by this means prevent the consequential seizure. This has
produced a belief that, at least in some cases, the electrical energy in the
brain indicated by such reaction can be duplicated under controlled conditions
and can be used to control a brain center other than at the place at which the
excessive aberrant energy is resent. Hence, the method and present. of this
invention contemplates conditions where implanted electrodes for detection and
control may be placed in selected parts of the brain not directly involved with
the excessive pattern.
Temporal lobe epilepsy is a typical disease where it is believed to be necessary
to provide deep implanted electrodes; first of all to detect the electrical
presence of the aberrant energy and second of all to counteract locally this
excessive aberrant energy. The method and apparatus of this invention is intended
to provide the detection means and the electrical signals necessary to counteract
and restrain these excesses.
SUMMARY OF THE INVENTION
This invention may be summarized at least in part with reference to its objects.
It is an object of this invention to provide both the method and the means of
monitoring the brain of a mammal by means of permanently inserted electrodes
in selected critical areas of the brain. By connecting these electrodes to a
monitoring device, safety limits for brain signal outputs can be evaluated and
upon indications of excess outputs counteracting signals can be fed to the brain
to prevent aberrant activity as produced in certain mental illness conditions
and epilepsy seizures.
In addition to the above summary the following disclosure is detailed to insure
adequacy and aid in understanding of the invention. This disclosure, however,
is not intended to prejudice that purpose of a patent which is to cover each
new inventive concept therein no matter how it may later be disguised by variations
in form or additions of further improvements. For this reason there has been
chosen a specific circuit diagram showing a means of employing the signals within
a brain of a mammal and by monitoring and counteracting excessive energy showing
a preferred means for preventing these excesses. This specific embodiment has
been chosen for the purposes of illustration and description as shown in the
accompanying drawings wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 represents a block diagram showing the principal operation of the apparatus;
FIG. 2 represents a pictorial representation of a human brain and the typical
implanting of three electrodes for control of epileptic seizure conditions,
and
FIG. 3 represents a diagram showing the attachment of and the support of the
apparatus to and by a human.
In the following description and in the claims various details will be identified
by specific names for convenience, these names, however, are intended to be
generic in their application. Corresponding reference characters refer to like
members throughout the three figures of the drawings.
The drawings accompanying, and forming part of, this specification disclose
certain details for the purpose of explanation of the broader aspects of the
invention, but it should be understood that details may be modified without
departure from the concept of the invention and that the invention may be incorporated
in other structural forms than shown.
PRINCIPLE OF OPERATION AS SEEN IN THE
ASSOCIATED BLOCK DIAGRAM
In the skull or head 10 of the mammal a common electrode 12 is placed into the
frontal bone or other zero level activity point from which to detect levels
of normal and abnormal electrical energy created in the brain. This electrode
is connected by a conductor 13 to an electronic circuit.
The second detecting electrode 14 is placed into one of the critical brain areas
such as the eleptogenic lesion portions of the skull 10, while a third electrode
16 is placed into a control point of the brain. This may be in the same area
as the detecting electrode or a different area of the brain.
Signals from electrode 14 are fed through a conductor 20 to an inverting electronic
device 22 which changes the electrical phase of the detected signal in preparation
for use by a comparison circuit 24. The signal from the inverter 22 is fed to
the comparison circuit through a conductor 26.
A reference voltage level R, which typically may be about 10 millivolts in the
case of a human, is set by the doctor in charge who has determined by appropriate
tests the level of voltage in the brain beyond which the patient to which the
device is affixed needs a countermotive force brought to action to quell the
ensuing anticipated storm. This reference voltage after the level has been established
is set and then is fed to the comparison circuit 24 through a conductor 28.
The comparison and analog addition circuit 24 will perform a vector addition
so that the resultant R-X should be a quantity negative in phase to that of
the original detected value X from electrode 14. The resultant is such that
X+(R-X) equals the value R, the normal set level. However, it may be found that
the point of control as compared to the point of detection may be scale factors
apart. When this occurs a level set amplifier 30 provides compensation for such
a condition.
Between the output from comparison circuit 24 which is fed to amplifier 30 is
a filter 32 which receives the output (R-X) from circuit 24 as fed through conductor
34. This filter 32 is used to prevent the electronics of the brain analysis
from interfering with other electrical functions such as heart beat and respiration.
An oscillator 40 is adapted to generate a high frequency signal which signal
is used as a carrier for the feedback information being communicated to the
brain point of control.
Since the synaptic chains (in the brain) have the manifestation of semiconductors
in that they act as diode detectors as in a radio circuit the information provided
to the snyaptic circuits is oriented in such a manner that the normal operation
of the nervous system will now detect the control data at minimum energy level
to accomplish the needed reduction of the brain energy at the localized areas
and provide an elimination of the excess electrical energy in the brain.
Signals from the modulator 30 are sent through conductor 42 to a safety limit
circuit 44 which provides standby passive and active networks which act as a
limiting fuse to insure and prevent any excessive energy from the said electrical
apparatus to be fed to the brain to cause or affect the brain or other nervous
system. Signals from the circuit 44 to electrode 16 is carried by conductor
46. A battery power supply 50 energizes the circuit and because of the serious
nature of this control device and what a deficiency in energization would cause
preferably includes a self test circuit with a low limit control 54 and an alarm
56 for extra protection.
Referring next to FIG. 3, there is depicted the normal arrangement and mounting
of the apparatus on the patient. The electrodes 12, 14 and 16 are implanted
in the brain in the skull 10 of the patient 60 to be treated and controlled.
Conductors 13, 20 and 46 carry the signals and controlling voltage to the electronic
circuits carried in a small case 62. The components carried by the case are
enclosed in phantom outline in FIG. 1. Except for the battery power which is
contemplated to be a small battery, the circuits providing the inverter 22,
the comparison and analog addition 24, filter 32, modulator 30, safety circuit
44, oscillator 40 and self test circuit 54 are all contemplated to be solid
state minaturized as much as possible. The reference voltage set is usually
an adjustable resistor located within the case and set by key means to prevent
an accidental change. It is contemplated that the case 62 when used externally
is less than the size of a package of cigarettes. With integrated circuitry
the case 62 may be made even smaller for implanting under the skin of the patient
60.
USE AND OPERATION
Automatic feedback control is the essence of this invention in that this control
receives signals indicating aberrant energy from the brain, analyses it electronically
as necessary and with a proper safety and power supply means then feeds electric
energy back into the brain in opposition to the original aberrant level so that
the net resultant voltage, current and/or electrical field in localized areas
on the brain is maintained at no level greater than that experienced during
normal behavior. The electronic feedback device of this invention is applied
not only to those types of epilepsy where aura is electrically seen prior to
an actual seizure (typified by some types of Grand Mal and Temporal Lobe Epilepsy)
but also is applied to some types of mental illness where psychic storms occur
providing electrical activity in the brain similar to that of epilepsy but having
as its manifestations psychic storms instead of physiological seizures.
The means of detecting and controlling the voltage level of the brain is through
the use of implanted electrodes 12, 14 and 16. The reason for employing implanted
electrodes as compared to surface electrodes is to provide the exact point of
application in the brain where either the point of detection or the point of
control can be found without having the electrical path through the skull either
deterioriate the signal in terms of the detection signal due to the impedance
of the fluids, tissue, skull bone and other media between such point of detection
and an external point. Similarly, a control signal for feedback data, if applied
externally, would require a larger electrical signal to produce a comparable
control. Typical electrical voltages represented in medical research studies
reveal that when monitored internally a normal brain pattern signal can reach
10 millivolts while the same signal monitored outside the skull produces a level
of approximately 10 microvolts.
The aura condition of an epileptic seizure can in fact increase the electrical
activity a factor of 10 times to a level 100 millivolts (when monitored internally).
Hence, for a corrective signal to be applied in opposition to such an aberrant
level, a minus 90 millivolts level would be internally applied whereas approximately
minus 90 volts would be externally applied; a quantity which could be dangerous.
Therefore, in the present invention internal electrodes are to be used so that
the voltage control will be at low levels which is safe.
The concept of automatic feedback has been used in the field of servo technology
for many years. The uniqueness of the present invention is the application of
automatic feedback theory and devices wherein the electrical energy of a mammal
such as a human is considered part of a servo loop in the automatic feedback.
The normalizing of this current flow provides a resultant improvement in the
mammal's performance where without such feedback control afflictions such as
epilepsy and mental illness prevent the normal behavior of that particular mammal
and the resulting deterioration caused by the affliction.
The employment of this system requires implanted electrodes, transdermal wires
and external electronics. It is noted that just as history with heart pacemakers
has shown that totally implanted devices can be made practical, so also is it
anticipated that this device with sufficient experience and history will be
implanted with the application of electronic miniaturization. The miniature
electronic detection and control device of this invention will be capable of
being totally implanted thus eliminating transdermal wire with the inherent
possibility of damage and failure of the system.
In use, detected signal from electrode 14 is carried by conductor 20 to an inverting
circuit 22 where the signal is reversed in polarity (minus the reference voltage
level) in order to be added to the aberrant brain electrical level during the
epileptic or psychic storms. This causes the brain voltage to be reduced to
that of the reference level. This action is similar to that of adding several
voltages together in an analog computer at a "summing junction" where the resultant
electrical levels are the algebraic sum of all voltages added at that point.
This, of course, takes into consideration the sign or phase of the voltages
being added.
The "common" or "ground" electrode 12 is used as a reference point against which
the electrical levels at the point of detection, the point of control and all
other computing reference and safety electrical levels is judged and conditioned.
The inverted signal -X from circuit 22 is carried by conductor 26 to the comparison
and analog addition circuit 24. Also to electronic circuit 24 is fed signal
R which is carried by conductor 28 and is the reference voltage level set by
the doctor. Another signal is the brain signal from the "common" electrode 12
which is fed to this comparison circuit. Direct current power to operate the
electronic circuitry is derived from the power supply 50 which has its own related
safety and self-test circuitry 54 which when used as a permanently installed
unit includes a low limit alarm 56 which indicates when a malfunction or voltage
loss occurs.
The comparison and analog addition circuitry 24 receives the inverted signal
-X from conductor 26 and combines this algebraically with signal R carried by
conductor 28 so that the electrical quantity R-X is produced as a raw signal
yet to be conditioned for use as the ultimate feedback signal. This raw signal
is fed by conductor 34 to the filter 32 which removes all frequency components
which could effect vital functions such as respiration and heart action. The
frequency band usable for these functions is approximately 5 to 40 herz. The
signal entering the modulation and level set amplifier 30 is the electrical
quantity R-X limited within the frequencies of F to F2 (approximately 5 to 10
herz).
The oscillator 40 and modulator level set amplifier 30 are both operated from
the same battery power supply 50, noted above.
The oscillator generates a high frequency carrier signal wherein there is created
a selected frequency having a range from 40,000 herz to 1 million herz. The
need to use a high frequency carrier is so as to utilize the lowest voltage
possible in the carrier electrical signals and also to utilize the inherent
electrical phenomenon manifest in the synapsis of the brain. Since the electrical
nerve pathways in the body are really composed of synapsis which react to provide
electrical energy transfer similar to the semiconductor devices called diodes
the operator of the device is able to forecast the utilization of these synaptic
pathways as diode detectors. This means that the diode characteristic which
is used in radio circuits to separate the audio information from the high frequency
carrier signal is like the present circuit of this invention where it is planned
to use the conditioned feedback signal to detect and provide for brain control
utilizing the brain synapsis. The brain synapsis is emloyed to demodulate the
correct data from the high frequency carrier which by itself is not seen by
the rest of the body. The level set amplifier 30 is set by the doctor so that
the particular mammal being treated has the determined electrical levels set
to compensate for the particular levels required to stablize the brain activity
of that mammal. If the control signal is fed back into the same area from which
the electrode received signals are set, the voltage is likely to be at unity
value with respect to the originating signal. However, when it is necessary
to apply the control signal at a point of control which is different from the
point of detection by the electrodes it will be required to use a ratio scale
to increase or decrease the control signal experimentally to determine that
signal level necessary at the point of control which is required to quell or
stabilize the detected aberrant energy in the brain.
The modulator 30 receives the high frequency signal generated by the oscillator
40 and impinges on the signal the envelope of frequencies entering the modulator
and level set amplifier 30. These frequencies include the electrical signal
quantity R-X filtered from F1 to F2 by filter 32 which modulates in amplitude
the high frequency signal. The resulting conditioned electrical signal is sent
by conductor 42 to the safety limit circuit 44.
This safety limit circuit 44 provides additional electrical safeguards to prevent
either momentary or long term pulses or continuous electrical signals from developing
to a level which will be injurious to the mammal involved. As the time constant
of energy of the physiological mammal is in terms of milliseconds and the electrical
condition and functioning of the control circuit is in terms of microseconds,
the electronic circuit acts at a rate which is responsive and available to assist
the physiological needs of the mammal.
Self-test circuit 54 is designed to assure the mammal, when human, to which
this device is connected that the electronic circuit is in an operative condition
ready for activiation without any jeopardy of the operation arising from low
battery voltage.
It is anticipated, as above noted, that the initial electronics and power source
(battery and control safety circuits) will occupy a volume less than a pack
of standard cigarettes and be externally carried on the user. With the use of
micro electronics it is further anticipated that this size can ultimately be
further reduced and the electronics and power source be mounted beneath the
skin surface of the user in the form of a small wafer.
Terms such as "left," "right," "up," "down," "bottom," "top," "front," "back,"
"in," "out" and the like are applicable to the embodiment shown and described
in conjunction with the drawings. These terms are merely for the purpose of
description and do not necessarily apply to the position in which the apparatus
for monitoring and counteracting excess brain energy may be constructed or used.
While this particular embodiment of the apparatus and method of use has been
shown and described it is to be understood the invention is not limited thereto
since modifications may be made within the scope of the accompanying claims
and protection is sought to the broadest extent the prior art allows.