U.S. patent number 3,629,521 [Application Number 05/001,334] was granted by the patent office on 1971-12-21 for hearing systems.
This patent grant is currently assigned to Intelectron Corporation. Invention is credited to Joseph L. Lawrence, Henry K. Puharich.
United States Patent |
3,629,521 |
Puharich , et al. |
December 21, 1971 |
HEARING SYSTEMS
Abstract
The present invention relates to the stimulation of the
sensation of hearing in persons of impaired hearing abilities or in
certain cases in persons totally deaf utilizing RF energy. More
particularly, the present invention relates to a method and
apparatus for imparting synchronous AF or "acoustic" signals and
so-called "transdermal" or RF signals. Hearing and improved speech
discrimination, in accordance with one aspect of the present
invention, is stimulated by the application of an AF acoustical
signal to the "ear system" conventional biomechanism of hearing,
which is delivered to the brain through the "normal" channels of
hearing and a separate transdermal RF electrical signal which is
applied to the "facial nerve system" and is detectable as a
sensation of hearing. Vastly improved and enhanced hearing may be
achieved by imparting an AF acoustic signal to the ear system by
means of "conventional" transducers, such as electroacoustic
speakers of "in the ear" hearing aids; piezoelectric or mechanical
transducers of conventional "bone conduction"-type hearing aids;
and so-called "intraoral bone conduction transducers" of the type
employed in the hearing system disclosed in Puharich and Lawrence
U.S. Pat. No. 2,995,633 and No. 3,170,993 and No. 3,156,787, and by
simultaneously applying a transdermal signal, which signal is an RF
carrier signal amplitude modulated with AF information across the
head of the subject, the head acting as capacitance in LC series
resonance of the RF carrier frequency. Importantly, the applied
balanced transdermal signal is in the form of a substantially pure
sine wave, and it is applied to the head through one bare and one
insulated electrode. The applied transdermal signal is applied to
the periaural and stylomastoid regions of the head and,
accordingly, the apparatus of the invention may be readily adapted
for use in the temples of "eyeglass" hearing aid devices.
Inventors: |
Puharich; Henry K. (Ossining,
NY), Lawrence; Joseph L. (New York, NY) |
Assignee: |
Intelectron Corporation (New
York, NY)
|
Family
ID: |
21695507 |
Appl.
No.: |
05/001,334 |
Filed: |
January 8, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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682152 |
Nov 13, 1967 |
3497637 |
|
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446267 |
Apr 6, 1965 |
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Current U.S.
Class: |
607/56; 381/151;
434/112; 381/327; 381/381; 381/326 |
Current CPC
Class: |
A61F
11/04 (20130101) |
Current International
Class: |
A61F
11/04 (20060101); A61F 11/00 (20060101); H04r
025/00 () |
Field of
Search: |
;179/17R,17BC,17E,17H,17S ;128/1.5 |
Primary Examiner: Claffy; Kathleen H.
Assistant Examiner: Kundert; Thomas L.
Parent Case Text
RELATION TO COPENDING APPLICATIONS
This application is a continuation-in-part of our copending
application Ser. No. 682,152, filed Nov. 13, 1967, and now U.S.
Pat. No. 3,497,637, and a continuation-in-part of our copending
application Ser. No. 446,267, filed Apr. 6, 1965, now abandoned.
This application is also related to our copending application Ser.
No. 633,035, filed Apr. 24, 1967, now U.S. Pat. No. 3,563,246. This
pertinent subject matter of the aforementioned applications is
hereby incorporated by reference.
Claims
We claim:
1. A method for enhancing speech discrimination by a human subject
of an AF signal comprising the steps of
a. amplifying said AF signal and introducing said amplified signal
to a region immediately adjacent the "ear canal" of said
subject,
b. modulating an RF carrier signal with said AF signal to produce a
transdermal signal,
c. balancedly applying said predetermined sites of transdermal
signal to the facial nerve system of the subject at opposite sides
of the head at the periaural and stylomastoid regions thereof,
d. the applications of said amplified AF signal and of said
transdermal signal being synchronous.
2. The method of claim 1, further characterized in that
a. said TD signal is applied to each side of the head through an
inductor.
3. The method of claim 2, further characterized in that
a. said transdermal signal is applied to the head at peak LC in
series resonance at the carrier frequency.
4. The method of claim 1, further characterized in that
a. said transdermal signal is applied through a pair of electrodes
one of which is bare and the other of which is insulated,
b. said bare electrode is placed on a first side of the head and
said AF signal is applied to the opposite side of the head.
5. Apparatus for enhancing speech discrimination in a hard of
hearing subject, comprising
a. means for amplifying an AF signal and introducing said amplified
signal to a region immediately adjacent the "ear canal" of said
subject,
b. means for modulating an RF carrier signal with said AF signal to
produce a transdermal signal,
c. means for balancedly applying said transdermal signal to the
facial nerve system of the subject at opposite sides of the head at
predetermined sites of the periaural and stylomastoid regions
thereof,
d. the applications of said amplified AF signal and of said
transdermal signal being synchronous.
6. The apparatus of claim 5, further includes
a. a pair of inductor means through which said transdermal signal
may be applied to the head of the subject.
7. The apparatus of claim 5, further characterized in that
a. said transdermal signal is applied to the head at peak LC series
resonance at the carrier frequency.
8. The apparatus of claim 5, which is further characterized in
that
a. said means for balancedly applying said transdermal signal to
the facial nerve system of the subject at opposite sides of the
head at predetermined sites of the periaural and stylomastoid
regions thereof includes a pair of electrodes, one of which is bare
and the other of which is insulated.
9. The apparatus of claim 5, further characterized in that
a. means for amplifying said AF signal and introducing said
amplified signal to a region immediately adjacent the "ear canal"
of said subject, and said means for balancedly applying said
transdermal signal to the facial nerve system of the subject at
opposite sides of the head at predetermined sites of the periaural
and stylomastoid regions thereof are housed within a frame
means.
10. The apparatus of claim 9, in which
a. said frame means includes an eyeglass frame and temples,
b. said means for balancedly applying said transdermal signal to
the facial nerve system of the subject at opposite sides of the
head at predetermined sites of the periaural and stylomastoid
regions thereof includes a pair of electrodes mounted on inner
surfaces of said temples.
11. The apparatus of claim 8, in which said insulated electrode
comprises
a. a first layer comprising a layer of conductive material adapted
to be directly connected to said signal source,
b. a second layer comprising a thin self-supporting film of
insulating material superimposed on said layer of conductive
material,
c. a third layer comprising a laminate of insulating film
conductive foil-insulating film superimposed on said
self-supporting film and adapted to contact the skin of said
subject, and
d. means maintaining said layers in unbonded surface contact with
one another.
Description
SUMMARY OF THE INVENTION
Heretofore, several systems employing so-called "dual stimulation"
have been proposed for use in the aiding of the hearing of persons
who are partially deaf. Some of these systems have employed dual
modes of acoustical stimulation; for example, a conventional
air-conducted acoustical signal may be delivered to the ear canal
through an earphone type of speaker while a separate bone-conducted
acoustic signal is delivered to the same normal channels of
hearing, i.e., ear system or conventional hearing biomechanism,
through an appropriately situated bone conductor. It has also been
broadly proposed heretofore to combine acoustic hearing with
electrically stimulated hearing to aid deaf or partially deaf
persons. The present invention is directed to a specific
improvement in the latter type of dual stimulation hearing systems
and provides a significant improvement in hearing and speech
discrimination over what has heretofore been obtainable in the
art.
Specifically, the vastly improved results of the method and
apparatus of the new invention are obtained by the employment of a
new and improved transdermal transmitting system; the employment of
new and improved transdermal transducer means for coupling the
transdermal signal to the subject; and the employment of specific
circuit parameters to achieve maximum improvement in hearing.
More specifically, the apparatus of the present invention delivers
an acoustic signal to an earphone or bone conductor type transducer
and simultaneously delivers a transdermal signal to the head of the
user at contralateral, periaural, and/or stylomastoid regions of
the head. The applied transdermal signal is a narrow width,
amplitude modulated carrier signal, which carrier is usually in the
range of 18 to 36 kHz. and which carrier is generated and coupled
to the head of the subject in a manner whereby the transdermal
signal is constantly driven across the head at peak LC series
resonance of the carrier frequency. Appropriate circuitry is
provided in order to maintain the transdermally applied signal at
the peak LC series resonance despite changes in the capacitance of
the coupling of the transdermal signal to the head of the subject
which may be occasioned by physiological changes in the
subject.
Importantly and in accordance with an important principle of the
present invention, improved speech discrimination is achieved by
applying the transdermal signal to the head in the form of a
substantially pure sine wave. Heretofore, applied sine waves have
tended to be distorted by the head. However, in accordance with the
invention, when the signal is applied to the stylomastoid regions
of the head through one bare transdermal electrode and one
insulated transdermal electrode placed contralaterally of the head,
distortion of the sine wave is effectively eliminated.
In the case of totally deaf subjects who cannot "hear" any acoustic
signals whatever through the conventional hearing biomechanism,
i.e., the "ear system," the use of two bare electrodes has enabled
the totally deaf to perceive sounds transmitted to the brain
"transdermally" through the single stimulus of a transdermal,
amplitude modulated RF signal, coupled in peak LC series resonance
of the carrier frequency.
For a more complete understanding of the present invention and a
better appreciation of its attendant advantages, reference should
be made to the following detailed description taken in conjunction
with the accompanying drawings.
DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic view of a dual stimulus hearing system,
mounted in an eyeglass frame and embodying the principles of the
present invention;
FIG. 2 is an enlarged, cross-sectional view of an improved
transdermal electrode means for use in coupling transdermal signals
to a subject for the practice of the present invention;
FIG. 3 is a preferred circuit arrangement for transdermal signal
generating apparatus of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Referring now to FIG. 1, audio information is introduced through
microphone 11 to a transdermal signal generator 10, of the type
disclosed in copending applications Ser. No. 633,035, now U.S. Pat.
No. 3,563,246; Ser. No. 682,152; now U.S. Pat. No. 3,497,637; and
Ser. No. 446,267, now abandoned. The output of signal generator 10
is applied both "acoustically" and "transdermally" to the head H of
a subject in the following manner and in accordance with the
principles of the present invention.
The transdermal (TD) signal, an amplitude modulated balanced RF
signal, is coupled to the contralateral stylomastoid regions of the
head through two separate inductors 12 and 13, a dielectric covered
electrode 14, and a bare metal electrode 15, which electrodes are
mounted on the inner surfaces of eyeglass temples T, as shown in
FIG. 1. That is to say, the TD signal levels are balanced on each
side of the head for optimum speech discrimination in accordance
with the invention. The dielectric covered electrode 14, which is
shown in greater detail in FIG. 2 and described more specifically
hereinafter, is placed on the same side of the head as the magnetic
speaker 25 or other conventional transducer such as a bone
conductor, which imparts an amplified acoustic signal directly into
the ear system of the subject. The bare electrode 15 is always
placed on the opposite side of the head from the speaker 25 and the
dielectric covered electrode 14, in accordance with a specific
aspect of the present invention and in order to minimize distortion
of the pure sine wave type of transdermal signal applied to the
head. As shown in FIG. 1, electrodes 14 and 15 are connected to the
output of the TD transmitter 10 by conductors 15' and 14',
respectively.
The transdermal (TD) signal generator 10 may advantageously
incorporate certain of the features described in a copending
application, Ser. No. 633,035, filed Apr. 24, 1967, now U.S. Pat.
No. 3,563,246, by Henry K. Puharich and Joseph L. Lawrence and also
certain features described in an earlier application, Ser. No.
446,267, filed Apr. 6, 1965, now abandoned, by the same inventors.
Reference to these applications may be made for further
details.
More specifically and with reference to FIG. 1, the output of the
transdermal signal generator 10 includes the pair of electrodes 14,
15, one of which is covered with a dielectric material (14) and the
other of which is bare (15), although in certain applications (e.g.
for totally deaf persons) both may be bare. In series with the
electrodes 14, 15 are large inductances 12, 13, advantageously in
the range of 2 to 30 millihenries and adjustable within that range
for the accommodation of different subjects. The TD signal
generating circuitry of the transmitter 10, once energized and
periodically pulsed, will oscillate at a frequency, herein referred
to as the carrier frequency, which is substantially in a circuit
resonant relation with the body of the subject, for maximum
effectiveness of the power input, as described in more detail in
the above-mentioned copending applications.
Desirably and as an important aspect of the invention, the
inductances 12, 13 are selected, with respect to a given subject,
to provide a carrier signal at a frequency on the order of about 18
to about 36 kHz. By designing and constructing the circuit for the
TD transmitter 10 so that the inductances 12, 13 are the primary
determinants of resonant frequency, in relation to the capacitance
of the coupled electrodes 14, 15, the resonant frequency may be
kept constant notwithstanding momentary changes in circuit
capacitance due to physiological and other changes in the body of
the subject.
In accordance with the principles of the present invention, an
in-phase acoustic or AF signal is simultaneously applied to the
head of the subject through a conventional transducer such as an
electromagnetic speaker of an earphone 25. The acoustic signal is
derived from the transdermal transmitter 10 and is applied to the
coil 18 of the magnetic speaker 25 by connecting one side of the
coil 18 to the conductor 14' by conductor 18', while the other side
of the coil 18 is connected to a conductor 19' which is connected
to an auxiliary bare metal electrode 19, which is placed against
the side of the head (above the ear) opposite the site of the bare
transdermal electrode 15. In accordance with the principles of the
invention, two separate circuits will be completed through the
head, a transdermal circuit between the electrodes 14 and 15 and
the acoustic circuit in which one side of the coil 18 is connected
directly to the TD transmitter while the other side of the coil 18
is connected through the head to the other side of the TD
transmitter 10.
In accordance with the principles of the invention, vastly improved
hearing and speech discrimination may be obtained by a person
having impaired hearing when the stem of FIG. 1 is operated in the
following manner. A desired audio input in the form of an audio
(AF) signal may be delivered to the transdermal transmitter system
10 through an input microphone 11 and the RF output of the
transmitter will then be transmitted to the head of the subject
applied thereto in the form of synchronous transdermal (RF) signals
and acoustic (AF) signals, the combined effect of which, on
hearing, will be significantly better than if either type of signal
stimulation had been used independently. That is to say, using a
conventional acoustic type earphone hearing aid, the subject's
hearing and speech discrimination abilities typically will be
enhanced (over completely unaided hearing) approximately 50
percent; the same may be said for the use of a transdermal type
hearing aid by itself. However, when both AF and RF stimulations
are used simultaneously and in accordance with the inventive
principles, hearing abilities and speech discrimination have been
enhanced (over completely unaided hearing) as much as 75 percent.
Therefore, there is a definite increase in hearing (in terms of PB
speech discrimination) over and beyond what has heretofore been
available by the use of either pure acoustic stimulation or pure
transdermal stimulation, which is attributed to synergistic effects
of the combination of AF and RF signals in the manner
described.
More specifically and by way of example, a sample group comprised
of 12 hard of hearing patients was measured in a "first or control
testing" with standard audiometry techniques, and it was found that
the average speech discrimination ability of the group was 26.2
percent as measured with phonetically balanced words, or the "PB
test." This measurement represented a "control" or standard for
comparison. Thereafter, the 12 patients took several weeks of TD
therapy in accordance with the principles and inventions set forth
in detail in our copending application, Ser. No. 633,035, filed
Apr. 24, 1967, for "Electrotherapy System." When measured in a
"second testing" with the same type of acoustic earphone PB test as
used in establishing the control level, the average PB speech
discrimination score of the group showed 43.0 percent or an
increment of 16.8 percent. Following the "second testing," the
group of patients was tested in a "third or TD testing" with the TD
signal rather than the acoustic signal, as the speech signal
source, and the average PB speech discrimination of the group was
54 percent, an increment of 27.8 percent. Following the second and
third testing, the group was tested with the signal source of the
invention which combined the earphone signals of the second testing
and the TD signal of the third testing, which signals were
synchronously applied in accordance with the invention. Remarkably,
the average PB speech discrimination score of the group was raised
to 73.8 percent, an improvement of 47.6 percent.
In accordance with one more specific aspect of the present
invention, the dielectric covered electrode 14 may have the
following configuration which has been found to couple, in a highly
efficient manner, transdermal signals to the head of the subject.
The electrode 14 comprises three layers, a fine wire mesh conductor
52; a 0.25 mil Mylar film 54 superimposed on the mesh; and a heat
bonded laminate 56 of 0.25 mil Mylar--1-mil aluminum foil--0.25 mil
Mylar superimposed on the layer 54. The layers 52, 54, 56 loosely
contact one another but are substantially unbonded throughout their
interfaces. Furthermore, the integrity of the electrode 14 may be
preserved mechanically by uniting the peripheral portions of the
layers with cement or using a plastic housing disc 58 to hold the
layers in the aforementioned contacting, but unbonded, relation.
The disc electrode 14 may be used to advantage in any transdermal
system such as those transdermal hearing and therapeutic systems
illustrated and described in the aforementioned copending
applications and may be formed as an integral part of an eyeglass
hearing aid.
In the illustrated configuration of the electrode 14, the unbonded
laminar construction provides highly effective transdermal energy
transfer (i.e., more power and less distortion) from a signal
source to the nervous system. It is theorized that the wire mesh
conductor layers of the electrodes tend to maximize the nonuniform
distribution of energy of the TD signal, while the loose or
floating intermediate Mylar film layers tend to provide infinite
capacitive adjustments as the layer flaps freely relative to the
conductor. Furthermore, it is believed that the laminated layer
which contacts the skin of the subject tends to smooth out
nonuniformities of energy concentration which exist in the other
two layers. That is to say, the foil conducts laterally of the
direction of energy transfer, thus counteracting and preventing
undue energy concentrations at the skin-electrode interface.
The importance of the multiple layers and the significance of their
loose or unbonded relationship may be demonstrated by a comparison
to a similar, but bonded, structure. Were the electrode layers to
be bonded at their interfaces, energy transfer would occur,
however, hearing improvement and minimization of distortion would
be significantly less than that for the unbonded arrangement.
Likewise, while an electrode configuration having only two layers,
a conductor layer and a Mylar layer, would, in fact, transfer
transdermal energy, the efficiency of the transfer is significantly
less than when the third layer of a Mylar-aluminum-Mylar laminate
is employed.
The operation of the new system is quite simple and is as follows.
The output signal from the TD transmitter 10 is applied
transdermally and in peak LC series resonance to the head of the
subject through the dielectric covered electrode 14 and the
oppositely placed bare electrode 15 in the manner described
hereinabove. The acoustic signal is applied to the head of the
subject in phase with the transdermal signal through the acoustic
earphone 25 or, if desired, through another appropriate suitable
acoustic transducer such as a conventional bone conductor.
Regardless of the choice of acoustic transducer (it being
understood that it is possible in some instances to employ an
intraoral, bone conductor type transducer), the acoustic transducer
is placed on the same side of the head as the dielectric covered
electrode of the transdermal electrode pair 14, 15. In this manner,
through a mechanism not yet completely understood, there appears to
be some synergistic effect between the dielectric covered electrode
14 and the acoustic transducer 25. The dual AF and RF signals then
provide the subject with a vastly enhanced sensation of hearing in
comparison to the hearing improvement that has heretofore been
available with either of a transdermal type signal stimulation or
an acoustic type signal stimulation.
The principles of the present invention may be used to adapt
existing, conventional acoustic hearing aids in the following
manner, without otherwise altering a conventional hearing aid,
i.e., one comprising a microphone, amplifier, and earphone. It is
necessary only to attach one side of the conventional coil 18 of
the hearing aid earphone 25 to the head via conductor 19' and bare
electrode 19 while conducting the other side of the conventional
hearing aid speaker coil 18 to the same side of the head through an
insulated electrode 14 appropriately directly connected to the
other side of the speaker coil 18. Additionally, an adjustable
resistance of from 0 to 10 kilohms and a diode of the type IN 34
are placed in series with the speaker coil 18, as shown in FIG. 1.
With these two modifications, a conventional acoustic-type hearing
aid may contribute to improved hearing performance by its further
combination with a transdermal system comprising the transmitter
10, the inductors 12 and 13 and the capacitive coupling electrode
15 and the capacitive coupling dielectric covered electrode 14, in
the manner generally shown in FIG. 1. This modified system will
ordinarily employ only the microphone 11 of the transdermal system
and will dispense with the microphone of the hearing aid (not
shown). The RF transdermal signal and the AF acoustic signal are
independently delivered in synchronism to the head H of the
listener through the electrodes 14, 15 and the earphone 25,
respectively. It should be understood, however, that the diode 20
and the resistor 21 illustrated in FIG. 1 are necessary only when
adapting a conventional hearing aid of "synergistic boosting" by a
separately provided transdermal stimulation system. When the
combined stimulation hearing system is supplied as an original
unit, such as shown in FIG. 3, the volume control arrangement,
provided by the resistor 20 and the diode 21, is not necessary.
A circuit arrangement of a transdermal transmitter 10 having a
balanced output and "automatic carrier frequency control" is
illustrated in FIG. 3. The output of the TD signal generator of
FIG. 3 is applied to the head of the subject through inductors 12,
13 and a pair of electrodes 14, 15, one of which is bare and one of
which is dielectrically covered. As mentioned hereinabove, in
certain applications where stimulation of hearing in the totally
deaf is desired through transdermal stimulation only, it is
necessary to employ two bare electrodes which are applied to
contralateral stylomastoid sides of the head.
The circuit of FIG. 3, comprises five transistors 151-155,
respectively; 21 resistors, reference numerals 161-181,
respectively; nine capacitors, 141-149, respectively; and one
transformer 191, appropriately interconnected by conductors in the
manner shown in FIG. 3. In this version of an "automatic carrier
frequency controlled transdermal transmitter," the transistors 151,
156, and 157 cooperate to form a constant current differential
amplifier which feeds the emitter followers of the transistors 153
and 154. These transistors 153 and 154 in turn feed a series
resonant circuit, which includes the inductors 12 and 13 and the
human head, itself, which is, of course, disposed therebetween, as
shown. In this manner, the head of the subject functions as a
capacitor, as should be understood.
In accordance with the principles outlined hereinabove, at resonant
frequency of this circuit, the current within the circuit peaks and
the voltage drop across the resistor 164 becomes maximized. This
maximum voltage across the resistor 164 is in turn fed to the base
of the transistor amplifier 152 and through a modulation network
comprised of diodes 92 and 93 and fed back to the input of the
differential amplifier. Therefore, the transistors 152, 153, 154,
155, and 156, in accordance with the principles of the invention,
form an oscillator circuit, the frequency of which is determined by
the inductors 12 and 13, and instantaneous capacitance of the head
H. In this circuit, the resistor 174 provides a level
adjustment.
As shown and as will be appreciated, the audio signal is introduced
into the circuit of FIG. 3 through the microphone 11 and is fed
from a conventional hearing aid amplifier 100 to the base of the
emitter follower 151, which drives the above-described modulation
transformer 191. The resistors 180 and 181 prevent the appearance
of DC on the coil side of the capacitors 47 and 48.
While the circuit of FIG. 3 is currently preferred for operating
the system of the present invention, it should be understood that
any appropriate transmitting circuit which is adapted to deliver an
amplitude modulated carrier signal in the range of approximately 18
to 36 kHz. to the head of a subject in LC series resonance will be
acceptable for the purposes of the present invention. Accordingly,
the circuit of FIG. 3 should be taken as illustrative of the
principles of the invention and not limiting thereof.
* * * * *