U.S. patent number 3,563,246 [Application Number 04/633,035] was granted by the patent office on 1971-02-16 for method and apparatus for improving neural performance in human subjects by electrotherapy.
This patent grant is currently assigned to Intelectron Corporation. Invention is credited to Joseph L. Lawrence, Henry K. Puharich.
United States Patent |
3,563,246 |
Puharich , et al. |
February 16, 1971 |
METHOD AND APPARATUS FOR IMPROVING NEURAL PERFORMANCE IN HUMAN
SUBJECTS BY ELECTROTHERAPY
Abstract
A method of patient rehabilitation by electrotherapy including
periodically electrically stimulating the patient in the region of
his facial nerve system by a controlled alternating electrical
treatment signal, which signal is an amplitude modulated, double
sideband signal of less than 100 kHz. The treatment signal is
applied to the patient's head through a pair of electrodes
comprised of two bare electrodes or two insulated electrodes, or
one insulated electrode and one bare electrode. The patient's head
is an element in an LC series resonant circuit established with the
treatment signal source.
Inventors: |
Puharich; Henry K. (Ossining,
NY), Lawrence; Joseph L. (New York, NY) |
Assignee: |
Intelectron Corporation (New
York, NY)
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Family
ID: |
24538022 |
Appl.
No.: |
04/633,035 |
Filed: |
April 24, 1967 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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446267 |
Apr 7, 1965 |
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Current U.S.
Class: |
607/55; 331/47;
600/26; 607/66; 607/69; 331/56 |
Current CPC
Class: |
A61N
1/32 (20130101) |
Current International
Class: |
A61N
1/32 (20060101); H05g 000/00 () |
Field of
Search: |
;128/362,380,404,409,413,419,420,421,422 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lowe; Delbert B.
Parent Case Text
RELATED PATENTS AND APPLICATIONS
The present invention is closely related to the subject matter of
our prior U.S. Pat. Nos. 2,995,633, 3,156,787, 3,170,993, and
3,267,931, and to the subject matter of our copending U.S.
application Ser. No. 446,267, filed Apr. 7, 1965, now abandoned.
With respect to certain of the subject matter hereof, the present
application is a continuation in part of said copending application
Ser. No. 446,267.
Claims
We claim:
1. Apparatus for treating human subjects for the purpose of
effecting hearing ability rehabilitation, which comprises:
a. a plurality of electrodes including two insulated and two
uninsulated electrodes, said electrodes being adapted to contact
physically contralateral regions of the facial nerve region of a
subject;
b. a plurality of open oscillator circuits, each of which is
adapted to oscillate at a different frequency and to provide a
carrier signal when completed;
c. selector switch means for connecting predetermined selected
electrode pairs and predetermined open oscillator circuits,
different pairs of said electrodes being adapted for use with
different ones of said open oscillator circuits;
d. the oscillator circuits being adapted to be completed upon
closure of said switch means and application of said electrodes to
said subject and having circuit parameters so chosen as to provide
predetermined LC series resonant frequency conditions in
conjunction with the subject and with the selected electrodes
applied to the subject; and
e. means for applying am an amplitude modulating signal with not
more than 100 percent modulation to said oscillator circuits in a
manner productive of a double side bank treatment signal of less
than 100 kHz.
2. The apparatus of claim 1, further characterized by said open
oscillator circuits including inductance coils of large enough
reactance in relation to the capacitance of the coupling between
said electrodes and a subject and to the carrier frequency to
maintain said LC series resonant conditions while accommodating
limited changes in said capacitance due to physiological variations
in the subject.
3. The apparatus of claim 1, further characterized by:
a. said means for applying a modulating signal comprising a pure
tone generator for tones in the range of approximately 20--20,000
Hz.; and
b. means being provided for varying the frequency of said tones
from a minimum value of not less than approximately 20 Hz. to a
maximum value of not more than approximately 20,000 Hz. and back to
said minimum in a sweep cycle of not significantly less than about
ten minutes duration.
4. The apparatus of claim 3, further characterized by said pure
tone generator including means for varying the amplitude of the
tone signal over a substantial modulation range in cycles
significantly shorter than those of said sweep cycle.
5. A method of treating human subjects for the purpose of a
effecting hearing ability rehabilitation which comprises the steps
of:
a. developing an alternating carrier signal of approximately 2--60
kHz. with a circuit which includes the head of the subject;
b. controllably amplitude modulating said carrier signal with an
audio frequency signal to provide a double side band treatment
signal of less than 100 kHz., limiting said amplitude modulation of
said carrier signal to not more than 100 percent;
d. applying said treatment signal to the head of the subject in the
region of the facial nerve system under conditions of substantial
LC series circuit resonance; and
e. continuing the application of said treatment signal for a
predetermined period of stimulation of not less than several
minutes.
6. The method of claim 5, further characterized by said double side
band treatment signal being modulated with cyclically increasing
and decreasing signals varying between an upper limit of
approximately 20,000 Hz. and a lower limit of approximately 20
Hz.
7. The method of claim 6, further characterized in that said
treatment signal is modulated within a cyclical period of about 10
minutes.
8. The method of claim 7, further characterized in that said
treatment signal is modulated between 0 percent and not more than
100 percent on a cyclical basis of substantially greater frequency
than said cyclical period.
9. The method of claim 5, further characterized in that said
electrical treatment signal is applied to the head of the subject
through the tragal areas of the ear and/or the stylomastoid areas
by the application of a physically contacting electrodes
thereto.
10. A method of treating human subjects for the purpose of
effecting hearing ability rehabilitation, in which the subject is
given one of or more treatments, comprising:
a. applying electrodes to the subject in the region of the facial
nerve system to establish an LC series resonant coupling with an
oscillator circuit, said circuit including the head of the subject
and being capable of generating a carrier signal of approximately
2--60 kHz.
b. amplitude modulating said carrier signal with an A-F signal to
generate a treatment signal of less than 100 kHz., said treatment
signal comprising said carrier signal not more than 100 percent
modulated with said audio frequency signal; and
c. applying said treatment signal to the subject for discrete time
intervals and varying the A-F component of said treatment signal
within said intervals throughout predetermined and regularly
controlled ranges.
11. A method of improving neural performance in human subjects,
which comprises:
a. electrically stimulating the subject in the region of the facial
nerve system by a controlled electrical treatment signal; and
b. said treatment signal including a carrier signal generated at a
frequency substantially corresponding to the circuit resonance
frequency of the circuit, including the subject, said carrier
frequency being in the range of 2--60 kHz. and being amplitude
modulated not more than 100 percent with an audio signal to provide
a double sideband signal of not more than 100 kHz.
12. The method of claim 11, which is intended principally for the
purpose of rehabilitating the hearing abilities, and which is
further characterized by said audio frequency signal being
controllably varied between upper and lower end regions of a
spectrum of approximately 20--20,000 Hz.
13. The method of claim 12, further characterized by said
electrical stimulation being applied in a series of discrete
treatment periods of not less than several minutes each, each of
said treatment periods being separated from the others by intervals
greater in duration than the duration of said treatment periods.
Description
Whereas our prior patents and our prior application are directed to
unique methods and equipments for imparting sensations of sound to
human subjects, through controlled electrical stimulation of the
facial nerve system, the present invention is more specifically
directed to techniques of therapy, utilizing many of the principles
of our prior inventions, whereby to effect hearing rehabilitation
in many hard-of-hearing patients, as well as achieving other
desirable therapeutic advantages.
BACKGROUND OF INVENTION
For many years, the medical arts have made advantageous use of
electrical energy stimulations, to achieve various desired effects
upon the body of a human subject. A typical well-known example is
the conventional diathermy treatment, by which heat is generated
within the body tissues, through the controlled application of
radio frequency energy. Electric shock treatments are used
occasionally in psychiatric treatment. And, considerable work has
been done in the art in connection with achieving various
therapeutic effects through the use of electrically induced sleep.
Efforts also have been made in the past to achieve therapeutic
effects upon hearing loss patients through the application of
extremely high frequency energy; however, such efforts have not
been entirely successful due to certain shortcomings in equipment
and procedural approach, which have been obviated by the present
invention.
SUMMARY OF INVENTION
In accordance with one significant aspect of the invention, a
basically new therapeutic procedure is provided, involving
specifically controlled electrostimulation of the patient, possibly
accompanied by audible stimulation, whereby, over a period of
treatments, the subnormal hearing abilities of a variety of
patients, suffering from a variety of hearing loss problems, can be
significantly rehabilitated. One fundamental aspect of the
invention involves the discovery that the patient should be
electrically stimulated, in the region of the facial nerve system,
using an alternating carrier signal of relatively low (compared
with previous efforts) frequency, typically around 60 kHz. maximum.
This carrier frequency signal is imparted to the subject in such a
way as to constitute substantially the resonant frequency for the
output circuit of the system, which includes the subject.
In the procedure of the invention, the resonant frequency carrier
signal is applied to the subject in accordance with a
predetermined, controlled schedule. This schedule includes
amplitude modulation of the carrier signal at modulation
frequencies corresponding to the audible range of hearing of a
typical human subject, for example from about 20 Hz. to about
20,000 Hz. The subject thus is electrically stimulated by an
amplitude modulated, resonant frequency carrier signal of such
characteristics that it can produce sensations of sound within the
subject, or at least within a subject having relatively normal
faculties.
A particularly advantageous aspect of the invention resides in the
provision of circuit arrangements, for application to the subject
in the region of the facial nerve system, which enable
substantially resonant circuit conditions to be maintained without
extraordinary variations in the frequency of the carrier signal, so
that uncontrolled changes in circuit parameters, resulting from
such causes as physiological variations in the subject, can be
accommodated.
Another advantageous aspect of the invention is the development of
a clinical regimen, enabling specific application of the inventive
treatment concepts to a wide variety of hearing loss patients. This
enables standardized treatment programs to be given in most
instances, although specialized treatment programs may be required
in particularly difficult cases. The use of standardized treatment
programs is particularly desirable in the present environment, in
that it renders the entire treatment series susceptible of
relatively automated control, as by means of a prepared tape
program, for example.
As a secondary, but by no means insignificant, objective, the
therapy program of the invention appears to have therapeutic
benefits with respect to a wider range of conditions than hearing
loss alone, and it is an objective of the invention to apply the
treatment program to other areas of rehabilitation as
appropriate.
For a better understanding of the invention, reference should be
made to the following description of a preferred embodiment, and to
the accompanying drawing.
DESCRIPTION OF THE DRAWING
FIG. 1 is a simplified schematic representation of a typical signal
generating and controlling system, with appropriate data readout,
which may be advantageously used in connection with a clinical
program utilizing the procedures of the invention.
FIG. 2 is a simplified schematic representation of a circuit
arrangement, advantageously incorporated with the system of FIG. 1,
for applying controlled electrical signals to a human subject in
accordance with the procedures of the invention.
FIG. 3 is a simplified graphic representation illustrating a
program of power and frequency modulation of a carrier signal
applied to a subject in a typical therapeutic procedure according
to the invention.
DESCRIPTION OF THE INVENTION
In accordance with the procedural concepts of the invention, it has
been found that significant hearing rehabilitation, as well as
other desirable therapeutic effects, can be realized by applying a
course of therapy which involves a properly controlled
electrostimulation of the subject. In accordance with this
invention, it is of significance that the subject be
electrostimulated in the region of the facial nerve system, which
is well-defined nerve network believed to be confined substantially
to the head and neck areas of the human body. The character of the
stimulation, too, is significant, and this, in accordance with the
present invention, is in the form of an alternating carrier signal,
of a frequency advantageously below, say, 100,00 Hz. The carrier
signal is applied to the subject under conditions of circuit
resonance for the carrier frequency, and this aspect of the
procedure is believed to have considerable significance. In
addition, the carrier is a double sideband signal amplitude
modulated by an audio frequency signal, advantageously of
frequencies within the audible range of a typical subject.
As explained in our prior patents and application, it is possible
to create sensations of sound, within the brain of a typical human
subject, by stimulating the facial nerve system of the subject with
modulated electrical signals corresponding to the sounds sought to
be generated. The teachings of our prior inventions thus afforded a
particularly advantageous method and means for aiding or augmenting
the subnormal hearing capabilities of a subject by providing a
source of controlled electrical signals which, in effect, tended to
bypass certain of the ear mechanisms of the patient.
The present invention represents a valuable extension of our
previous inventions, in that it provides not only for the
augmentation of the subject's hearing facilities, but, with many
patients, can actually effect a rehabilitation of the subject's
natural hearing system, occasionally to such an extent that the
rehabilitated patient hears satisfactorily even without
augmentation or assistance.
The treatment of the present invention, in its most advantageous
specific form, involves the application of controlled electrical
stimulation to the subject, by means of electrodes applied to the
tragal areas of the ear and/or the stylomastoid areas of the neck.
Typically, the electrodes are either of the insulated (dielectric)
type or of the bare type, and they may be used in like or
dissimilar pairs, applied to like or dissimilar areas of the
subject, accompanied by appropriate circuit adjustments enabling
resonance to be maintained in the output circuit, which includes
the head of the subject, for the desired carrier frequency
range.
Experience has shown that different subjects may respond
differently to different types of stimuli, so it is difficult to
generalize as to a single optimum form of stimulation. However, it
appears that most subjects respond to one or more of the following
stimulus modes:
Mode 1A: Two bare electrodes are applied bilaterally in the
stylomastoid areas, with the output circuit being tuned to a
carrier frequency in the range of about 2 to 10 kHz. An audio
modulation band width of from about 20 to 2,000 Hz. is
utilized.
Mode 1B: Two bare electrodes are applied bilaterally to the
stylomastoid areas. The output circuit is tuned to accommodate a
carrier frequency in the range of about 10 to 20 kHz., and the
audio frequency bandwidth may extend from 2,000 to 8,000 Hz.
Mode 2: Two dielectric electrodes are applied bilaterally to the
tagal areas. The output circuit is tuned to accommodate a carrier
frequency in the range of about 40 to 60 kHz., and the contemplated
audio bandwidth range is from about 20 to 18,000 Hz.
Mode 3A: One bare and one dielectric electrode are utilized, with
the bare electrode being applied to the stylomastoid area and the
dielectric electrode being applied on the opposite side to the
tragal area. The output circuit is tuned for a carrier frequency in
the range of about 20 to 40 kHz., and the audio bandwidth
contemplated ranges from about 200 to 8,000 Hz.
Mode 3B: Electrode configuration is similar to Mode 3A. The output
circuit is tuned for a carrier frequency in the range of about 20
to 40 kHz., and the audio bandwidth contemplated ranges from about
200 to 10,000 Hz.
Although a specific patient may respond more favorably to one
stimulation mode than to another, it may be advantageous in some
instances to provide a standardized sequence of treatments
involving some exposure of the subject to all of the different
modes.
Advantageously, although the electrical energy applied to the
subject will vary somewhat according to the physiology of the
subject, and, more significantly, the mode of stimulation, it is
contemplated that the output voltage of the energizing system (as
measured between a center tap of an output circuit transformer and
ground) with two bare electrodes will range from around 1.4 volts
to around 2.5 volts (RMS). With one bare and one dielectric
electrode, the voltage may range from about 8 to about 18 volts.
And, with a pair of dielectric electrodes, the voltage may range
from about 20 to about 40 volts. The peak-to-peak reactive voltage
across the head of the subject may be significantly higher than the
above, depending upon the nature of the electrodes used. Thus, in a
typical application of bare electrodes, the peak-to-peak reactive
voltage may be around 12 volts. With one bare and one dielectric
electrode, the reactive voltage typically might be in the range of
200 to 400 volts. With a pair of dielectric electrodes, the
reactive voltage may have a much wider range, typically from about
1,200 to about 2,400 volts, for example.
Output current of the system (applied through the subject) may
typically be in the range of 0.8 to 2.8 milliamps (RMS) for bare
electrodes, 8 to 18 milliamps for one bare and one dielectric
electrode, and 20 to 45 milliamps for dielectric electrodes.
It will be understood, of course, that the foregoing current and
voltage values are intended not as a limitation on the scope of the
invention, but rather as being illustrative of the general ranges
of current and voltage values in which the practice of the
invention has been found to be most effective.
In accordance with the invention, a therapeutic procedure suitable
for a typical subject involves periodic stimulation treatments
given to the subject, such as hour-long sittings, or perhaps even
day-long sittings, with appropriate intervening rest periods. The
subject has applied thereto a pair of electrodes, which may be
either a like or dissimilar pair, depending upon the circumstances.
Usually, dielectric electrodes are applied in the tragal area and
bare electrodes are applied in the stylomastoid area. The applied
electrodes are then energized by an appropriately modulated carrier
signal, at the resonant frequency for the output circuit, as will
be described in more detail hereinafter. Typically, the carrier
frequency will fall between 2 kHz. and about 60 kHz., depending
significantly upon the electrode combinations utilized.
In accordance with the invention, the treatment signal is a double
sideband, amplitude modulated carrier signal, which is modulated by
a controllable audio frequency signal. By body mechanisms not
clearly understood, the subject is effectively able to demodulate
the impressed treatment signal, and apparently to derive therefrom
neural stimuli corresponding to those derived from a normal hearing
system. In this respect, a perfectly normal subject will
immediately be able to hear the sound of the audio frequency
modulating signal, substantially as if he were wearing a pair of
acoustical earphones. A patient requiring substantial
rehabilitation, on the other hand, may not derive any sensation of
sound from the impressed signal, at least in the initial stages of
treatment.
Most advantageously, the audio frequency modulating signal is
varied over a predetermined audio bandwidth in cycles of about 10
minutes. In other words, if the audio bandwidth ranges from, say
about 2,000 to 10,000 Hz., the frequency of the modulating signal
is varied, either progressively or in steps, from 2,000 to 10,000
Hz., and then back down to 2,000 Hz. in a period of about 10
minutes. In addition, the amplitude of the audio frequency signal
advantageously is varied from 0 to 100 percent of maximum amplitude
in cycles of about 1 second. The envelope of the audio frequency
signal typically is triangular or sine wave (log to linear
amplification), but in any event desirably cycles gradually in both
directions, as distinguished from having a modulation envelope
similar to a square wave or sawtooth wave, for example.
By way of example, the therapeutic procedure of the invention, as
applied to a typical deaf patient having a profound bilateral
sensorineural loss of hearing of about 20 years duration, might be
as follows:
At the commencement of treatment, the typical patient might be
anacoustic for pure tones in the frequency range from 125 to 8,000
Hz. at 100 db. pressure levels. At 125 db. pressure levels, the
patient is incapable of discriminating a single word, although the
sensation of noise could be experienced. A patient such as this is
considered totally deaf for word discrimination.
The typical patient is given 1 -hour treatments each day for a
week, during which selected electrode combinations are applied
across the head of the patient for predetermined periods. For each
combination, the carrier signal is brought to peak resonance and is
modulated with an audio frequency band ranging from a preselected
minimum to a preselected maximum for the stimulation mode, in a
cycling period of about 10 minutes. The audio frequency signal is
amplitude modulated between 0 and 100 percent with a triangular
envelope about once per second, the maximum amplitude of the audio
signal approximating or being slightly less than the amplitude of
the carrier signal.
After one week's treatments, the typical patient is given
electrical stimulation with pure tone. When the patient first
reports hearing a given frequency, say, 1,300 Hz., the
electrostimulation therapy program is commenced, using the
initially heard frequency as a starting point and stimulating the
patient upward and downward therefrom. As the treatment continues,
the patient will begin to hear tones continuously up and down from
the initial frequency. By the end of the second week, a typical
patient will be able to hear, through electrostimulation, pure
tones within a bandwidth from about 200 Hz. to about 4,00 Hz., and
also will be able to begin to distinguish frequency changes from
volume changes. This process of tone stimulation and tone
discrimination is continued for another week, and, at the end of
the third week, a typical patient will be able to hear tones within
the bandwidth of electrostimulation from about 100 to about 8,000
Hz.
At the commencement of the fourth week of treatment, the patient
usually is ready to be stimulated with complex audio frequency
waves, as distinguished from pure tones. The patient then may be
stimulated, using a magnetic tape source, for example, containing
rhythmic music and speech. As soon as the patient is able to
distinguish closely between speech and music, a process of speech
education is begun. This consists of live voice stimulation from a
therapist (i.e., the carrier signal is modulated by the therapist's
voice). Simultaneously, the therapist's voice is directed
acoustically at the patient, at a pressure level of about 80 db.
Under this program, the patient is given blocks of about 10 words
to learn by combined and synchronous electrostimulation and live
voice stimulation (electroacoustic stimulation). By the end of the
fourth week, a typical patient is able to learn to distinguish
about 25 words by means of this program of stimulation. The words
are so chosen that they readily combine into short sentences. When
the patient is able to discriminate such sentences, when given in
randomized order, at an accuracy level of 90 percent or better, it
is considered that the patient is recovering utilitarian
hearing.
By the fifth or sixth week, the typical patient usually is able to
give a 7 percent or better correct response to numbers chosen at
random and given to the patient by electroacoustic stimulation. At
this point in the program, the patient may be taught Spondaic
words. At this time, it may be desirable to fit the patient with an
acoustic hearing aid that is energized from the electrostimulation
source, so that the acoustic signal and the electrostimulation
signal are precisely in phase. After having learned to use the
hearing aid properly, the typical patient can score from 30 to 90
percent on Spondaic word lists, with electroacoustic
stimulation.
During the continuation of the therapeutic process, most patients
will show objective improvements in pure tone acoustic audiology
(determined without electrostimulation). Such improvements in
acoustic hearing ability have been found to last for an
indeterminate period of time, days in some cases and weeks in
others. However, it also has been found that the improved condition
may be maintained by periodic, short electrostimulation treatments.
The frequency of maintenance treatments required for any patient is
determined empirically.
For patients having extremely difficult hearing loss problems, the
ability to effect rehabilitation, to enable the patient to hear
even by electrostimulation, appears to be a function of time and
the number of treatments. In addition, in the later stages of
treatment, it has been found particularly advantageous to
supplement the electrostimulation with an acoustic stimulation.
There appears to be a definitely synergistic effect to the
combination of these signals, at least in difficult patients.
Although the foregoing reflects a composite of typical patient
responses, individual difficult cases may show optimum responses to
slightly different sequences of treatment. In all cases, however,
the subject is stimulated by a carrier frequency at or near the
resonance frequency of the output circuit, including the subject,
and the carrier signal is modulated by an audio frequency signal in
the range of the audible frequencies of a typical subject. A
summary of selected such individual cases is set forth below.
SUMMARY OF TYPICAL CLINICAL CASES
Case No. 1
The patient was a male, age 70, having clinical total deafness in
the left ear of 30 years' duration, following an episode of
Meniere's disease, and progressive presbyacusis in the right ear,
etiology unknown. The speech reception threshold for the patient's
right ear is 60 db., with a 36 percent Spondi word discrimination
capability at 95 db.
The patient was given daily transdermal electrical stimulation
therapy for a period of 14 days, according to the following
schedule:
a. The patient was first given a 10 minute treatment using
insulated electrodes applied to the tragal areas. A resonant
frequency carrier signal was applied to the patient, amplitude
modulated from 0 percent to 100 percent power in cycles of about 1
second. The carrier signal was (amplitude) audio modulated from 100
to 20,000 Hz. and back to 100 Hz. in an audio band cycle of about
10 minutes. The patient was then given a 5-minute rest period,
during which he was tested for audio bandwidth response to
controlled signals applied through the electrodes.
b. The patient then was given a 10 minute treatment, using one bare
and one insulated electrode, with the bare electrode being placed
upon the right stylomastoid area and the dielectric, or insulated,
electrode being placed upon the left tragal area. The carrier
signal power was modulated from 0 percent to 100 percent on a
1-second cycle, and an audio band cycle of about 10 minutes was
provided, during which the audio modulation of the carrier signal
was varied between about 50 and 10,000 Hz. and back to 50 Hz.
Thereafter, a 5-minute testing period was provided to determine the
patient's response to controlled signals applied through the
electrodes.
c. The patient was then given a further 10-minute treatment, using
bare electrodes applied at the stylomastoid areas, with a 1-second
power modulation cycle and a 10-minute audio band cycle between 50
and 3,000 Hz. After this, the patient was given a further 5-minute
testing period for determining response to controlled signals.
Tests conducted upon the patient indicated a significant extension
of the patient's high frequency audio range response, as a function
of the number of treatments, as determined by tests made with the
dielectric electrodes. Tests conducted with the bare electrodes
indicated minimal response, although favorable response was shown
upon further therapy, particularly within the middle frequency
range. (Paradoxically, the bare electrodes have been shown to be
most efficient with respect to rehabilitation of word
discrimination capability in the totally deaf.)
The patient's acoustic pure tone audiogram showed considerable
improvement, after 14 days of treatment, and this is considered
significant in cases of presbyacusis. At the same time, the
patient's Spondi word discrimination score, when tested at 100 db.,
improved from 36 percent at the beginning to 74 percent on the 14th
day.
The treatment was then continued as above specified for a total of
54 sessions, with the following indicated results:
Prior to the transdermal treatment the patient wore a large body
hearing aid. This was the only means whereby the patient could hear
speech in quiet areas. In a noisy environment this aid proved
ineffective for speech discrimination hearing. After 14 days of
transdermal treatment according to the invention, the patient was
able to get effective use from a small (Radioear, in-ear-canal
type) hearing aid. His discrimination had improved to the point
where he could effectively hear speech with this aid in a noisy
environment.
Prior to treatment (for several years) head noises were prominent
and disturbing, and described by the patient as "subway train
sounds roaring through my head." By the 14th day of treatment, the
head noises had subsided to a level where they were not disturbing,
although still present. During the period from the 22nd to the 27th
treatments, the head noises recurred to their former loud and
disturbing level. However, they subsided by the 30th treatment, and
were scarcely noticeable to the patient thereafter while under
treatment.
During the 5 years prior to the transdermal treatment, the patient
was subject to attacks of vertigo at least once or twice a month.
During the initial period of treatment (3 months) the patient was
free of vertiginous attacks.
By the 22nd day of the treatment (the 18th Therapeutic Session) the
left ear of the patient began to show significant improvement in
the low frequency spectrum of the pure tone audiogram. By the 43rd
transdermal treatment the left ear had so improved that the patient
was able to hear words for the first time in thirty years.
Therefore, he was fitted with Sonotone M72 binaural hearing aids.
As he learned to use a binaural aid, he was able to repeat live
voice sentences correctly 100 percent. When tested with the right
ear aid alone he could repeat such sentences 90 percent. When
tested with the left ear aid along (masking to right ear) he could
repeat sentences with 80 percent accuracy. After the 54th
transdermal treatment, with the use of the Sonotone binaural aids,
the patient was able to resume full time participation in his
business.
The patient's improved abilities were found to have remained
substantially at the same levels when the patient was retested
about 3 months later. However, after the patient had been off of
therapy for 2 months, his attacks of vertigo reoccured. Therapy was
resumed, and in 2 weeks the symptoms of vertigo disappeared, and
have not returned.
The following is a summary of the hearing changes observed in the
patient after 54 one-hour each treatments, given over a 3-month
period. ##SPC1##
Case No. 2
The patient was a male, age 181/2 years, normal except for
congenital hearing loss, probably due to Rh factor pathology.
The patient was given a total of 70 minutes of treatment at one
visitation, which included the following:
With dielectric electrodes applied bilaterally over the tragal
area, a carrier frequency signal of 49 kHz., with pure tone
modulation from 100 to 12,000 Hz. This stimulation was continued
for 15 minutes.
Thereafter, the patient was given a 17-minute treatment, using one
dielectric electrode and one bare electrode, both applied
bilaterally to the stylomastoid area. The resonant carrier
frequency applied was 36 kHz. with pure tone modulation from 100 to
4,000 Hz.
Next, the patient was given a 17-minute treatment with dielectric
electrodes applied bilaterally over the tragal areas, substantially
as in the first described sequence.
The patient was then given short periods of stimulation with
acoustical assistance with live voice in one instance and hearing
aids in another.
A 10-minute stimulation sequence was then given, using bare
electrodes applied to the stylomastoid areas, using a carrier
frequency of about 3.1 kHz. and voice modulation. This was followed
by a similar sequence, in which the patient was aided by a
conventional hearing aid.
In audiomentry tests performed on the patient before and after a
single 70-minute treatment, remarkable improvement was shown after
the treatment, as indicated in the following table. ##SPC2##
The patient showed the above-indicated enhanced auditory activity
for a period of 2 days following the transdermal electrostimulation
therapy. The patient was then begun on a course of therapy
involving 1-hour treatments, twice a week, shortly reduced to one
session per week. Maintenance therapy has now been empirically
established as one treatment (1 hour) per month to maintain the
enhanced abilities indicated in the above table.
Case No. 3
The patient is a male, age 38, with a history of hearing loss at
age 5, following episodes of measles, mumps, and scarlet fever.
There is present bilateral symmetrical severe sensorineural loss of
hearing activity. The patient has shown marked improvement in word
discrimination acuity after 20 treatments of 1 hour each, in
accordance with the invention. A combination of acoustic
stimulation plus transdermal electrostimulation allows the patient
to carry on normal conversational speech and, for the first time in
the patient's life, he is able to use an amplified telephone to
carry on a conversation.
In the following table, Part A, acoustic audiometry test results
for the patient are indicated, before and after treatment. Part B
of the table sets forth the patient's enhanced acuity when the
acoustical stimulus is enhanced by transdermal electrostimulation.
##SPC3##
Case No. 4
The patient was a female, age 27, having a history of progressive
sensorineural loss of hearing acuity, probably of otosclerotic
origin. After 12 1-hour treatments, the patient's speech audiometry
showed a significant increase in PB word discrimination, although
this was not accompanied by any significant increase in pure tone
audiometry. After the 27th 1-hour treatment, a PB word
discrimination test, with the patient being electrically and
acoustically stimulated, indicated repeated scores of 100 percent,
as against a pretreatment control level of 42 percent for the left
ear and 58 percent for the right ear.
After 30 treatments, the patient, assisted by a conventional
hearing aid, was able to carry on conversations effectively in high
noise level environments (e.g., 90 to 100 db.).
In the following table, Part A sets forth the patient's speech
audiometry prior to treatment; Part B sets forth the patient's
speech audiometry subsequent to the 12th 1-hour treatment; and Part
C indicates the patient's hearing acuity after the 12th treatment,
when subjected to electroacoustic stimulation. ##SPC4##
##SPC5##
Case No. 5
The patient was a male, age 72, with total deafness in the left ear
of 55 years' duration, etiology unknown. The right ear showed
progressive presbyacusis over the past 16 years. The patient's
hearing loss was complicated by senile symptoms, with agitated
depression occasionally, and memory confusion. The patient was
given one course of treatment, of 60 minutes each day for 24
sessions. One bare and one dielectric electrode were applied
bilaterally over the stylomastoid area, using a 36 kHz. amplitude
modulated sine wave carrier, with audio modulation from 60 to
12,000 Hz. After the treatment, the patient showed significant
improvement in the right ear acoustic audiometry, and a small
improvement in the left ear. The patient achieved significant
improvement for the right ear with respect to acoustic source PB
word discrimination, which was even further improved with
electroacoustic stimulation. This is reflected in the following
table: ##SPC6## ##SPC7##
A most noteworthy therapeutic effect on the patient, apart from
hearing improvement, was the fact that most of his behavioral
symptoms of senility cleared up after 6 weeks of the
electrostimulation therapy. His short term memory improved,
temporal disorientation cleared up, and irritability and emotional
instability diminished markedly. Moreover, according to the
patient, Tinnitus and head noises diminished markedly.
Case No. 6
The patient was female, age 48, whose hearing was normal until she
was treated with Kanamycin therapy for a fulminating Peritonitis.
Typical ototoxic sensorineural hearing loss followed the
administration of Kanamycin. The patient was given 26 1-hour
treatments, according to the invention. She showed steady
improvement with continued therapy, and, at times, can use an
unamplified telephone to hear voice conversation.
The following table indicates that the patient's acoustic audiogram
improvement was positive, but small. However, the improvement in PB
word discrimination was remarkable, in response to acoustic source
alone, as well as with electrostimulation. ##SPC8##
Case No. 7
The patient was a male, age 83, with presbyacusis, whose onset was
first noticed over 40 years ago. The patient could not get
effective help with a conventional hearing aid and, therefore, did
not use one. He retired from business because he was unable to
discriminate in conferences and on the telephone.
The patient was given 36 1-hour treatments in accordance with the
procedures of the invention. By the 16th treatment, the patient
began to make effective use of the telephone, again. After 36
treatments, the patient's PB word discrimination improved from 40
percent before therapy to 84 percent after therapy. His hearing had
improved to the extent that he could hear normal conversation, both
in quiet and in noisy environments, without a hearing aid.
Case. No. 8
The patient was female, age 58 58, with profound bilateral
sensorineural loss of 30 years' duration, believed to be of
otosclerotic origin. The patient showed absolutely no pure tone
response with the most powerful audiometer available. Before
treatment, her speech discrimination was 0 percent, a case of total
deafness.
The patient is undergoing a continuing series of treatments. After
the 20th treatment, she indicated ability to hear an occasional
word during conversation. By the 23rd treatment, she was able to
identify 80 percent of selected words given at 100 db. The patient
is now able to discriminate more than 10 percent of Spondi words,
given at a level of 95 db. She continues to improve slowly in her
word discrimination hearing acuity, with continued therapy in
accordance with the invention.
Case No. 9
The patient was female, age 52, with a history of progressive
hearing loss bilaterally over the past 20 years. Recently, she
suddenly lost all hearing completely. Before commencing treatment,
she showed absolutely no response to air conduction or bone
conduction at peak audiometer output, and had no speech
discrimination. She also indicated subjective disturbance from
loudness and severity of head noises.
After 10 treatments in accordance with the invention, the a patient
showed no response to pure tones from a transdermal electrostimulus
source. By the 36th treatment, however, she was able to respond to
the electrostimulation pure tone source in the frequency range from
27 to b 5,100 Hz. on each ear, using one dielectric and one bare
electrode. It is noteworthy that the patient hears only with the
electrodes in the stylomastoid position, and then only on the side
of the bare metal electrode.
After the 49th treatment, the patient showed her first response to
an acoustic source, and the patient is now able to correctly repeat
20 percent of numbers, given at random from 1 to 10, using a
combination of electrostimulation and an acoustic source at 100
db.
This patient, who represents an extremely difficult case of total
deafness, is showing slow improvement in pure tone thresholds and
increases in audio band width response. Particularly notable,
however, has been the almost complete subsidence of the subjective
head noises, of which the patient complained prior to
treatment.
Case No. 10
The patient was male, age 77, with bilateral symmetrical
prebyacusis of about 8 year' duration. The patient wears a binaural
"radioear" air conduction hearing aid.
After 19 treatments in accordance with the invention the patient
shows significant improvement in pure tone threshold, in the low
frequency end of the audio spectrum. In addition, the patient shows
a slight improvement in PB word discrimination ability, in that the
right ear has improved from 72 percent discrimination prior to
treatment to 86 percent after, while the left ear has increased
from 60 percent to 80 percent. The ultimate prognosis in this case
is comparable to that reflected by the patient of Case No. 7.
Case No. 11
The patient was male, age 56, having a profound unsymmetrical
sensorineural hearing loss in the right ear, probably due to
petrous pyramid fracture at age 15.
Up to the 20th treatment, the patient could hear only in the
frequency range from 20 to 740 Hz. in the right ear, with
electrostimulation. Between the 22nd and the 24th treatments,
however, he was suddenly able to hear from 20 to 5,200 Hz. with
excellent tone discrimination in the right ear, with
electrostimulation. Concurrently, there was a small improvement in
the PB word discrimination acuity of the right ear, from 16 to 26
percent. A slight improvement also was reflected in the left ear,
although the initial hearing loss in the left ear was minor.
A summary of the foregoing case histories, reflecting principally
PB word discrimination acuity prior to treatment and after
treatment, is set forth below. ##SPC9##
Referring now to the drawing, and initially to FIG. 1, a clinical
apparatus suitable for a carrying out the process of the invention
includes two pairs of electrodes 10, 11 arranged selectively to be
applied to the subject and to be appropriately energized. One pair
of the electrodes, No. 10 in the illustration, is insulated, while
the other pair of electrodes is bare. Typically, the electrodes may
have a cross-sectional area of 3 square centimeters, usually
circular, and the insulated electrodes may be covered by one of
more films of a dielectric material, such as Mylar, having a total
thickness on the order of .25 mil.
The electrode pairs 10, 11 are electrode through ganged selector
switches 12, 13 which, in a plurality of operative serve to connect
the electrodes 10, 11 in circuit in various combinations to the
output conductors 14, 15. Thus, for purposes of illustration, the
selector switches 12, 13 may be designated as being associated with
the left side right side electrodes, respectively, and each switch
has a series of four contacts, designated A through D. Since the
switches are ganged to operate in unison, their contact positions
will be the same.
When the selector switches 12, 13 are in the A position, the output
conductors 14, 15 are connected to the bare electrodes 11. In the B
position, the output conductors are connected to the insulated
electrodes. In the C position, the conductor 14 is connected to the
left side insulated electrode 10, and the output conductor 15 is
connected to the right side bare electrode 11. In the D position,
the output conductor 14 is connected to the left side bare
electrode 11, and the conductor 15 is connected to the right side
insulated electrode 10. Thus, as will be understood, the A and B
switch positions involve the use of like pairs of electrodes, while
the C and D positions involve the use of dissimilar electrodes.
The output conductors 14, 15 are connected to stages 16 and 17 of
the selector switch, which operate in unison with the stages 12,
13. The switches 16 and 17 are appropriately connected to the
output terminals of a bank of three tuned oscillator circuits
18--20, to be described in more detail. Thus, the A contacts of the
switches 16, 17 are connected to the output terminals 21, 22 of the
oscillator 18, the B contacts are connected to the output terminals
23, 24 of the oscillator 19, and the C contacts are connected to
terminals 25, 26 of the oscillator 20. The C and D contacts of the
switches 16, 17 are jumped, so that the D contacts likewise are
connected to the oscillator 20. Thus, in any set position of the
selector switches 12, 13 and 16, 17, a selected like or dissimilar
pair of electrodes 10, 11 will be connected to the terminals of a
predetermined one of the oscillator circuits 18--20. The purpose of
this, as will be made more evident, is to provide for an optimum
resonant frequency in the output circuit for each type of electrode
pair which may be in use.
For informational purposes, a voltage meter 27 is connected between
the center taps of several transformers 28--30 incorporated in the
individual oscillator circuits 18--20, and one of the output
conductors 14, 15, to indicate the output voltage of the oscillator
circuit in use at a given moment. Likewise, an amperage meter 31 is
connected in series in one of the output lines 14, 15 to indicate
the magnitude of current being applied to the subject.
For monitoring the operation of the oscillator circuits, there are
connected between the center tap and one terminal of the oscillator
transformers 28--30, through a four-position selector switch stage
32, a voltage meter 33, oscilloscope 34, and frequency meter
35.
Various inputs to the system thus described typically include a
tape deck-preamp combination 36, a microphone-preamp combination
37, and a pure tone generator 38 with modulation and sweep
controls. An auxiliary input 39 also is provided for special input
devices. All of the foregoing feed through an input selector switch
40 to an amplifier 41 which feeds the input to all of the
oscillator sections 18--20.
The apparatus may also include a monitor earphone section 42, by
means of which the therapist may monitor the inputs. A signal
section 43 likewise is provided having pushbutton switches 44, 45
and indicator lights 46, 47, by means of which the patient may
signal responses to the therapist from time to time.
Referring now to FIG. 2, there is shown schematically a typical
amplifier-oscillator circuit arrangement for advantageous
incorporation in the system of the invention. In particular, the
output circuit oscillator system is especially advantageous in that
it provides for the generation of a carrier signal which is at all
times in or substantially in resonance with the output circuit,
which includes the subject. Moreover, the oscillator circuit is
effectively able to maintain resonance conditions as the a
parameters of the output circuit change with physiological changes
in the body of the subject, variations in electrode contact
pressures, etc.
The amplifier section 41 shown in FIG. 2 is a simple, two-stage
amplifier, the output section of which includes a transistor 50,
suitably a 2N1184B, the emitter side of which is connected through
a 680-ohm resistor 51 to the positive terminal of an 18-volt power
supply 52. The collector element of the transistor is connected
through a .01-microfarad condenser 53 to ground at 54, and the
signal output tap for the amplifier is also connected to the
collector electrode at 55. The base electrode of the transistor 50
is connected through a 1,000 ohm variable resistor 56 to the
positive side of the power supply and through a 1,000-ohm resistor
57 to the collector element of a transistor 58, suitably a 2N1481.
The emitter side of the input stage transistor 58 is connected
through a 1,000-ohm resistor 59 to ground and through a 35,000-ohm
resistor 60 to the collector of the output stage transistor 50. The
base element of the transistor 58 is connected to the input at 61.
It is also connected through a 100,000-ohm resistor 62 to the
positive terminal of the power source and through a 3,300-ohm
resistor 63 to ground.
The output signal of the amplifier stage 41 is applied to an
oscillator circuit (18, 19 or 20) which includes a pair of
electrodes 10 or 11 and the head of the subject 64. In accordance
with the present invention, the output circuit, including the
subject, is specially designed to constitute an LC oscillator
circuit having a resonant frequency in a desired frequency range,
most advantageously below 100,000 Hz. Of particular significance,
the oscillator circuit is designed to accommodate the fact that a
significant circuit component is the capacitance of the coupling
between the electrodes 10, 11 and the body of the subject. This can
vary widely as a function of frequency, and of the interface
conditions between the electrodes and the subject (e.g., assume
that the subject begins to perspire), and is also known to vary
with physiological changes in the subject having to do with his
emotional condition. In this respect, experience has shown that
capacitance across the head of a subject may vary as widely as from
about 0.002 to about 1 microfarad.
Since the circuit coupling to the subject is essentially
capacitive, and since the capacitance values of such coupling may
vary significantly because of factors beyond the control of the
therapist and which also may be transient in nature, the circuit
has incorporated therein relatively large inductances, a such that
the inductances are principally influential in determining the
resonant frequency of the oscillator system. Pursuant to this
arrangement, significant variations in the capacitance at the
subject will have a relatively suppressed effect upon the resonant
frequency of the circuit as a whole, such that the oscillator can
readily accommodate these changes in circuit parameters.
The design parameters of the oscillator circuit are such as to
oscillate at the desired carrier signal frequency. Accordingly, the
output of the amplifier stage 41 may be a low frequency signal,
which is combined in the oscillator stage with the higher frequency
carrier. The thus modulated carrier is applied to the subject 64 in
a manner which assures the resonance conditions which are
desired.
For a circuit as thus far described, intended for use in a
therapeutic program as described, the oscillator circuits 18--20
may be provided with added inductance, usually in the form of coils
65, 66 on opposite sides of the subject, which typically have the
following inductance values for the following circuit conditions:
The oscillator 18, connected for use in conjunction with a pair of
bare metal electrodes, most advantageously has a pair of series
inductances of 70 millihenries each, which experience indicates
provides for a carrier frequency oscillation in the range of 2 to
10 kHz. (It may also be desirable to provide a still further
oscillator, not specifically shown, having a pair of series
inductance elements of 2 millihenries each, for use in connection
with a pair of bare electrodes, to provide for a carrier frequency
oscillation in the range of about 10 to 20 kHz.) The oscillator 19,
intended for use in connection with the insulated electrodes 10,
advantageously includes a pair of inductance elements of 30
millihenries each, which experience indicates typically results in
a carrier frequency oscillation of 40 to 60 kHz. The oscillator 20,
intended for use with dissimilar pairs of electrodes,
advantageously has a pair of inductance elements of 50 millihenries
each, which experience indicates will provide a carrier frequency
oscillation of from about 20 to 40 kHz.
In the overall oscillator circuit, the amplifier output is
connected through a 180,000-ohm resistor 67, a .01 microfarad
condenser 68, and one of the large inductances 65 to one side of
the head of the subject. The other side of the subject's head is
connected through the inductance coil 66, one side of a transformer
69, which suitably may be an NH1702GA, and thence through conductor
70 to ground. The other coil of the transformer 69 is connected to
the collector element of a transistor 71, which suitably may be a
2N3053. The emitter element of the transistor is connected to
ground at 72, and the base element is connected between the
resistor 67 and capacitor 68 and through a diode 73 to ground.
When activated by signals from the amplifier stage 41, the
oscillator circuits will oscillate at a desired carrier frequency
signal, as a function of the LC parameters (principally) thereof.
Since the resonant circuit includes the subject itself, the carrier
signal typically can be applied under peak resonance conditions,
extraordinary changes in the circuit parameters being suppressed
through the utilization of relatively large inductance elements, as
described.
To accommodate the desired clinical procedure, at least the audio
tone generator input 38 desirably is provided with facilities for
varying the generator tone between the minimum and maximum desired
limits (e.g., 20 to 20,000 Hz.) on a fairly long cyclical basis,
such as an approximate 10 minute overall cycle, as reflected in
FIG. 3. While the generated tones are varying in accordance with
the long period cycle, the amplitude of the generated audio
frequency signal is also desirably modulated between 0 and 100
percent on a much shorter cycle, such as about 1 second, as
reflected in the upper portion of FIG. 3. This appears to have a
desirable, stimulating effect upon the patient.
The system also desirably is provided with means for controlling
the relative amplitude of the carrier signal and the modulating
audio frequency signal. Typically, the modulating signal amplitude
is slightly less (e.g., 80 to 90 percent) than the amplitude of the
carrier signal, although occasionally it may be desirable that the
modulating signal amplitude be as low as, say, 40 percent of the
carrier signal, and occasionally it may be larger, say, 120 percent
of the carrier signal.
The method and apparatus of the present invention have particular
significance in that they are useful in the effective
rehabilitation of hard-of-hearing patients. Thus, regardless of
whether the subject ultimately is given hearing augmentation, in
the form of a conventional acoustical hearing aid or in the form of
electrically stimulated hearing in accordance with our prior
inventions, or possibly both, the ability of the subjects to hear
naturally or with augmentation often may be enhanced by a prior
course of treatment in accordance with the invention.
In its basic form, the treatment of the invention involves a
programmed course of electrostimulation of the subject, in the
region of the facial nerve system, by means of an audio frequency
signal, within the typical audible range of the human subject. Most
effectively, this audio frequency signal is derived by appropriate
modulation of a higher frequency carrier signal, which carrier
signal is imparted to the subject under conditions of substantial
circuit resonance, and ideally at relatively low carrier signal
frequencies, typically on the order of less than 100,000 Hz.
It is possible that an electrostimulation program as contemplated
by the present invention in effect tends to exercise and restore
the initial capabilities of atrophied nerve networks of otherwise
hard-of-hearing patients, such that their ability to hear through
electrostimulation and otherwise is somewhat enhanced. However, it
is not intended that the invention be limited to a particular
theorization or explanation.
As will be understood, the specific treatment sequences recited
herein and the specific apparatus utilized therefor, are intended
to be illustrative only, as certain changes may be made therein
within the clear teachings of the disclosure. Accordingly,
reference should be made to the following appended claims in
determining the full scope of the invention.
* * * * *