United States Patent (11 3,629,521

72 Inventors Henry K. Puharich energy. More particularly, the present invention relates to a
Ossining; method and apparatus for imparting synchronous AF or
Joseph L. Lawrence, New York, both of "acoustic' signals and so-called "transdermal" or RF signals.
N.Y. Hearing and improved speech discrimination, in accordance
(21) Appl. No. 1,334 with one aspect of the present invention, is stimulated by the
(22 Filed Jan. 8, 1970 application of an AF acoustical signal to the 'ear system' con
45 Patented Dec. 21, 1971 ventional biomechanism of hearing, which is delivered to the
73) Assignee Intelectron Corporation brain through the "normal' channels of hearing and a
New York, N.Y. separate transdermal RF electrical signal which is applied to
Continuation-in-part of application Ser. No. the "facial nerve system' and is detectable as a sensation of
682,152, Nov. 13, 1967, now Patent No. hearing. Vastly improved and enhanced hearing may be
3,497,637, and a continuation-in-part of achieved by imparting an AF acoustic signal to the ear system
446,267, Apr. 6, 1965, now abandoned. by means of "conventional' transducers, such as elec
This application Jan. 8, 1970, Ser. No. troacoustic speakers of "in the ear' hearing aids; piezoelectric
1,334 or mechanical transducers of conventional "bone conduc
tion'-type hearing aids; and so-called "intraoral bone conduc
tion transducers' of the type employed in the hearing system
54 HEARING SYSTEMS disclosed in Puharich and Lawrence U.S. Pat. No. 2,995,633
11 Claims, 3 Drawing Figs. and No. 3,170,993 and No. 3,156,787, and by simultaneously
52 U.S. Cl........................................................ 179/107 R applying a transdermal signal, which signal is an RF carrier
51 int. Cl............ ... H04r 25/00 signal amplitude modulated with AF information across the
50 Field of Search............................................ 179/107 R, head of the subject, the head acting as capacitance in LC se
107 BC, 107 E, 107 H, 107 S; 128/.5 ries resonance of the RF carrier frequency. Importantly, the
Primary Examiner-Kathleen H. Claffy applied balanced transdermal signal is in the form of a sub
Assistant Examiner-Thomas L. Kundert
stantially pure sine wave, and it is applied to the head through
one bare and one insulated electrode. The applied trans
Attorney-Mandeville and Schweitzer dermal signal is applied to the periaural and stylomastoid re
gions of the head and, accordingly, the apparatus of the inven
ABSTRACT: The present invention relates to the stimulation tion may be readily adapted for use in the temples of
of the sensation of hearing in persons of impaired hearing "eyeglass" hearing aid devices.
abilities or in certain cases in persons totally deaf utilizing RF

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INVENTORS
HENRY K. PUHARCH
JOSEPH L. LAWRENCE

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HENRY K. PUHARCH
JOSEPH L LAWRENCE
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HEARNG SYSTEMS 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
RELATION TO COPENDINGAPPLICATIONS taken in conjunction with the accompanying drawings.
This application is a continuation-in-part of our copending DESCRIPTION OF DRAWINGS
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 FIG. 1 is a schematic view of a dual stimulus hearing system,
copending application Ser. No. 446,267, filed Apr. 6, 1965, mounted in an eyeglass frame and embodying the principles of
now abandoned. This application is also related to our 10 the present invention;
copending application Ser. No. 633,035, filed Apr. 24, 1967, FIG. 2 is an enlarged, cross-sectional view of an improved
now U.S. Pat. No. 3,563,246. This pertinent subject matter of transdermal electrode means for use in coupling transdermal
the aforementioned applications is hereby incorporated by signals to a subject for the practice of the present invention;
reference. FIG. 3 is a preferred circuit arrangement for transdermal
15 signal generating apparatus of the present invention.
SUMMARY OF THE INVENTION
DETAILED DESCRIPTION OF THE PRESENT
Heretofore, several systems employing so-called "dual INVENTION
stimulation' have been proposed for use in the aiding of the Referring now to FIG. 1, audio information is introduced
hearing of persons who are partially deaf. Some of these 20 through microphone 11 to a transdermal signal generator 10,
systems have employed dual modes of acoustical stimulation; of the type disclosed in copending applications Ser. No.
for example, a conventional air-conducted acoustical signal 633,035, now U.S. Pat. No. 3,563,246; Ser. No. 682,152; now
may be delivered to the ear canal through an earphone type of
speaker while a separate bone-conducted acoustic signal is U.S. Pat. No. 3,497,637; and Ser. No. 446,267, now aban
delivered to the same normal channels of hearing, i.e., ear 25
doned. The output of signal generator 10 is applied both
system or conventional hearing biomechanism, through an ap "acoustically'and "transdermally" to the head H of a subject
propriately situated bone conductor. It has also been broadly in the following manner and in accordance with the principles
proposed heretofore to combine acoustic hearing with electri of the present invention.
cally stimulated hearing to aid deaf or partially deaf persons. The transdermal (TD) signal, an amplitude modulated
The present invention is directed to a specific improvement in 30 balanced RF signal, is coupled to the contralateral
the latter type of dual stimulation hearing systems and pro stylomastoid regions of the head through two separate induc
vides a significant improvement in hearing and speech dis tors 12 and 13, a dielectric covered electrode 14, and a bare
crimination over what has heretofore been obtainable in the metal electrode 15, which electrodes are mounted on the
att. inner surfaces of eyeglass temples T, as shown in FIG. 1. That
Specifically, the vastly improved results of the method and 35 is to say, the TD signal levels are balanced on each side of the
apparatus of the new invention are obtained by the employ head for optimum speech discrimination in accordance with
ment of a new and improved transdermal transmitting system; the invention. The dielectric covered electrode 14, which is
the employment of new and improved transdermal transducer shown in greater detail in FIG. 2 and described more specifi
means for coupling the transdermal signal to the subject; and cally hereinafter, is placed on the same side of the head as the
the employment of specific circuit parameters to achieve max 40 magnetic speaker 25 or other conventional transducer such as
imum improvement in hearing. a bone conductor, which imparts an amplified acoustic signal
More specifically, the apparatus of the present invention directly into the ear system of the subject. The bare electrode
delivers an acoustic signal to an earphone or bone conductor 15 is always placed on the opposite side of the head from the
type transducer and simultaneously delivers a transdermal speaker 25 and the dielectric covered electrode 14, in ac
signal to the head of the user at contralateral, periaural, 45 cordance with a specific aspect of the present invention and in
and/or stylomastoid regions of the head. The applied trans order to minimize distortion of the pure sine wave type of
dermal signal is a narrow width, amplitude modulated carrier transdermal signal applied to the head. As shown in FIG. 1,
signal, which carrier is usually in the range of 18 to 36 kHz. electrodes 14 and 15 are connected to the output of the TD
and which carrier is generated and coupled to the head of the 50 transmitter 10 by conductors 15' and 14, respectively.
subject in a manner whereby the transdermal signal is con The transdermal (TD) signal generator 10 may ad
stantly driven across the head at peak LC series resonance of vantageously incorporate certain of the features described in a
the carrier frequency. Appropriate circuitry is provided in copending application, Ser. No. 633,035, filed Apr. 24, 1967,
order to maintain the transdermally applied signal at the peak now U.S. Pat. No. 3,563,246, by Henry K. Puharich and
LC series resonance despite changes in the capacitance of the 55 Joseph L. Lawrence and also certain features described in an
coupling of the transdermal signal to the head of the subject earlier application, Ser. No. 446,267, filed Apr. 6, 1965, now
which may be occasioned by physiological changes in the sub abandoned, by the same inventors. Reference to these appli
ject. cations may be made for further details.
Importantly and in accordance with an important principle More specifically and with reference to FIG. 1, the output
of the present invention, improved speech discrimination is 60 of the transdermal signal generator 10 includes the pair of
achieved by applying the transdermal signal to the head in the electrodes 14, 15, one of which is covered with a dielectric
form of a substantially pure sine wave. Heretofore, applied material (14) and the other of which is bare (15), although in
sine waves have tended to be distorted by the head. However, certain applications (e.g. for totally deaf persons) both may be
in accordance with the invention, when the signal is applied to bare. In series with the electrodes 14, 15 are large inductances
the stylomastoid regions of the head through one bare trans 65 12, 13, advantageously in the range of 2 to 30 millihenries and
dermal electrode and one insulated transdermal electrode adjustable within that range for the accommodation of dif
placed contralaterally of the head, distortion of the sine wave ferent subjects. The TD signal generating circuitry of the
is effectively eliminated. transmitter 10, once energized and periodically pulsed, will
In the case of totally deaf subjects who cannot "hear' any oscillate at a frequency, herein referred to as the carrier
acoustic signals whatever through the conventional hearing 70 frequency, which is substantially in a circuit resonant relation
biomechanism, i.e., the "ear system,' the use of two bare elec with the body of the subject, for maximum effectiveness of the
trodes has enabled the totally deaf to perceive sounds trans power input, as described in more detail in the above-men
mitted to the brain "transdermally' through the single stimu tioned copending applications.
lus of a transdermal, amplitude modulated RF signal, coupled Desirably and as an important aspect of the invention, the
in peak iC series resonance of the carrier frequency. 75 inductances 12, 13 are selected, with respect to a given sub

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ject, to provide a carrier signal at a frequency on the order of the earphone signals of the second testing and the TD signal of
about 18 to about 36 kHz. By designing and constructing the the third testing, which signals were synchronously applied in
circuit for the TD transmitter 10 so that the inductances 12, accordance with the invention. Remarkably, the average PB
13 are the primary determinants of resonant frequency, in speech discrimination score of the group was raised to 73.8
relation to the capacitance of the coupled electrodes 14, 15, percent, an improvement of 47.6 percent.
the resonant frequency may be kept constant notwithstanding In accordance with one more specific aspect of the present
momentary changes in circuit capacitance due to physiologi invention, the dielectric covered electrode 14 may have the
cal and other changes in the body of the subject. following configuration which has been found to couple, in a
In accordance with the principles of the present invention, 10
highly efficient manner, transdermal signals to the head of the
an in-phase acoustic or AF signal is simultaneously applied to subject. The electrode 14 comprises three layers, a fine wire
the head of the subject through a conventional transducer mesh conductor 52; a 0.25mil Mylar film 54 superimposed on
such as an electromagnetic speaker of an earphone 25. The the mesh; and a heat bonded laminate 56 of 0.25 mill Mylar
acoustic signal is derived from the transdermal transmitter 10 1-mil aluminum foil-0.25 mil Mylar superimposed on the
and is applied to the coil 18 of the magnetic speaker 25 by 15 layer 54. The layers 52,54, 56 loosely contact one another but
connecting one side of the coil 18 to the conductor 14' by are substantially unbonded throughout their interfaces.
conductor 18', while the other side of the coil 18 is connected Furthermore, the integrity of the electrode 14 may be
to a conductor 19' which is connected to an auxiliary bare preserved mechanically by uniting the peripheral portions of
metal electrode 19, which is placed against the side of the the layers with cement or using a plastic housing disc 58 to
head (above the ear) opposite the site of the bare transdermal 20 hold the layers in the aforementioned contacting, but un
electrode 15. In accordance with the principles of the inven bonded, relation. The disc electrode 14 may be used to ad
tion, two separate circuits will be completed through the head, vantage in any transdermal system such as those transdermal
a transdermal circuit between the electrodes 14 and 15 and hearing and therapeutic systems illustrated and described in
the acoustic circuit in which one side of the coil 18 is con the aforementioned copending applications and may be
nected directly to the TD transmitter while the other side of 25 formed as an integral part of an eyeglass hearing aid,
the coil 18 is connected through the head to the other side of In the illustrated configuration of the electrode 14, the un
the TD transmitter 10. bonded laminar construction provides highly effective trans
in accordance with the principles of the invention, vastly dermal energy transfer (i.e., more power and less distortion)
improved hearing and speech discrimination may be obtained from a signal source to the nervous system. It is theorized that
by a person having impaired hearing when the stem of FIG. 1 30 the wire
is operated in the following manner. A desired audio input in imize themesh conductor layers of the electrodes tend to max
nonuniform distribution of energy of the TD signal,
the form of an audio (AF) signal may be delivered to the while the loose or floating intermediate Mylar film layers tend
transdermal transmitter system 10 through an input to provide infinite
microphone 11 and the RF output of the transmitter will then freely relative to thecapacitive conductor.
adjustments as the layer flaps
Furthermore, it is believed
be transmitted to the head of the subject applied thereto in the 35
form of synchronous transdermal (RF) signals and acoustic tends to smooth out nonuniformities ofthe
that the laminated layer which contacts skin of the subject
(AF) signals, the combined effect of which, on hearing, will be which exist in the other two layers. That energy concentration
significantly better than if either type of signal stimulation had ducts laterally of the direction of energy transfer,thethus
is to say, foil con
coun
been used independently. That is to say, using a conventional
acoustic type earphone hearing aid, the subject's hearing and 40 teracting and preventing undue energy concentrations at the
speech discrimination abilities typically will be enhanced skin-electrode
The
interface.
importance of the multiple layers and the significance
(over completely unaided hearing) approximately 50 percent;
the same may be said for the use of a transdermal type hearing of their loose or unbonded relationship may be demonstrated
by a comparison to a similar, but bonded, structure. Were the
aid by itself. However, when both AF and RF stimulations are 45 electrode layers to be bonded at their interfaces, energy
used simultaneously and in accordance with the inventive transfer would occur, however, hearing improvement and
principles, hearing abilities and speech discrimination have minimization of distortion would be significantly less than that
been enhanced (over completely unaided hearing) as much as for the unbonded arrangement. Likewise, while an electrode
75 percent. Therefore, there is a definite increase in hearing configuration having only two layers, a conductor layer and a
(in terms of PB speech discrimination) over and beyond what Mylar layer, would,
has heretofore been available by the use of either pure 50 efficiency in fact, transfer transdermal energy, the
acoustic stimulation or pure transdermal stimulation, which is third layer of the transfer is significantly less than when the
of a Mylar-aluminum-Mylar laminate is employed.
attributed to synergistic effects of the combination of AF and The operation of the new system is quite simple and is as fol
RF signals in the manner described.
More specifically and by way of example, a sample group 55 lows. The output signal from the TD transmitter 10 is applied
comprised of 12 hard of hearing patients was measured in a "- transdermally and in peak LC series resonance to the head of
first or control testing" with standard audiometry techniques, the subject through the dielectric covered electrode 14 and
and it was found that the average speech discrimination ability the oppositely placed bare electrode 15 in the manner
of the group was 26.2 percent as measured with phonetically described hereinabove. The acoustic signal is applied to the
balanced words, or the "PB test.' This measurement head of the subject in phase with the transdermal signal
represented a "control' or standard for comparison. through the acoustic earphone 25 or, if desired, through
Thereafter, the 12 patients took several weeks of TD therapy another appropriate suitable acoustic transducer such as a
in accordance with the principles and inventions set forth in conventional bone conductor. Regardless of the choice of
detail in our copending application, Ser. No. 633,035, filed acoustic transducer (it being understood that it is possible in
Apr. 24, 1967, for "Electrotherapy System." When measured 65 some instances to employ an intraoral, bone conductor type
in a "second testing' with the same type of acoustic earphone transducer), the acoustic transducer is placed on the same
PB test as used in establishing the control level, the average side of the head as the dielectric covered electrode of the
PB speech discrimination score of the group showed 43.0 per transdermal electrode pair 14, 15. In this manner, through a
cent or an increment of 16.8 percent. Following the "second mechanism not yet completely understood, there appears to
testing," the group of patients was tested in a "third or TD 70 be some synergistic effect between the dielectric covered elec
testing' with the TD signal rather than the acoustic signal, as trode 14 and the acoustic transducer 25. The dual AF and RF
the speech signal source, and the average PB speech dis signals then provide the subject with a vastly enhanced sensa
crimination of the group was 54 percent, an increment of 27.8 tion of hearing in comparison to the hearing improvement that
percent. Following the second and third testing, the group was has heretofore been available with either of a transdermal type
tested with the signal source of the invention which combined 75 signal stimulation or an acoustic type signal stimulation.
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The principles of the present invention may be used to described modulation transformer 9, The resistors 180 and
adapt existing, conventional acoustic hearing aids in the fol 181 prevent the appearance of DC on the coil side of the
lowing manner, without otherwise altering a conventional capacitors 47 and 48.
hearing aid, i.e., one comprising a microphone, amplifier, and While the circuit of FIG. 3 is currently preferred for operat
earphone. It is necessary only to attach one side of the conven ing the system of the present invention, it should be un
tional coil 8 of the hearing aid earphone 25 to the head via derstood that any appropriate transmitting circuit which is
conductor 19' and bare electrode 19 while conducting the adapted to deliver an amplitude modulated carrier signal in
other side of the conventional hearing aid speaker coil 18 to the range of approximately 18 to 36 kHz. to the head of a sub
the same side of the head through an insulated electrode 14 ject in LC series resonance will be acceptable for the purposes
O of the present invention. Accordingly, the circuit of FIG. 3
appropriately directly connected to the other side of the
speaker coil 18. Additionally, an adjustable resistance of from should be taken as illustrative of the principles of the inven
0 to 10 kilohms and a diode of the type N 34 are placed in se tion and not limiting thereof,
ries with the speaker coil 18, as shown in FIG. 1. With these We claim:
two modifications, a conventional acoustic-type hearing aid 1. A method for enhancing speech discrimination by a
15 human subject of an AF signal comprising the steps of
may contribute to improved hearing performance by its
further combination with a transdermal system comprising the a. amplifying said AF signal and introducing said amplified
transmitter 10, the inductors 12 and 13 and the capacitive signal to a region immediately adjacent the "ear canal' of
coupling electrode 15 and the capacitive coupling dielectric said subject,
covered electrode 14, in the manner generally shown in FIG. b. modulating an RF carrier signal with said AF signal to
1. This modified system will ordinarily employ only the produce a transdermal signal,
microphone 11 of the transdermal system and will dispense c. balancedly applying said predetermined sites of trans
with the microphone of the hearing aid (not shown). The RF dermal signal to the facial nerve system of the subject at
transdermal signal and the AF acoustic signal are indepen opposite sides of the head at the periaural and
dently delivered in synchronism to the head H of the listener 25 stylomastoid regions thereof,
through the electrodes 14, 15 and the earphone 25, respec d. the applications of said amplified AF signal and of said
tively. It should be understood, however, that the diode 20 and transdermal signal being synchronous.
the resistor 21 illustrated in F.G. 1 are necessary only when 2. The method of claim , further characterized in that
adapting a conventional hearing aid of "synergistic boosting' a. said TD signal is applied to each side of the head through
an inductor.
by a separately provided transdermal stimulation system. 30
3. The method of claim 2, further characterized in that
When the combined stimulation hearing system is supplied as a. said transdermal signal is applied to the head at peak LC
an original unit, such as shown in FIG. 3, the volume control in series resonance at the carrier frequency.
arrangement, provided by the resistor 20 and the diode 21, is 4. The method of claim 1, further characterized in that
not necessary.
A circuit arrangement of a transdermal transmitter 10 hav 35 a said transdermal signal is applied through a pair of elec
trodes one of which is bare and the other of which is insu
ing a balanced output and "automatic carrier frequency con lated,
trol' is illustrated in FIG. 3. The output of the TD signal b. said bare electrode is placed on a first side of the head
generator of FIG. 3 is applied to the head of the subject and said AF signal is applied to the opposite side of the
through inductors 12, 13 and a pair of electrodes 14, 15, one 40 head.
of which is bare and one of which is dielectrically covered. As S. Apparatus for enhancing speech discrimination in a hard
mentioned hereinabove, in certain applications where stimula of hearing subject, comprising
tion of hearing in the totally deaf is desired through trans a. means for amplifying an AF signal and introducing said
dermal stimulation only, it is necessary to employ two bare amplified signal to a region immediately adjacent the "ear
electrodes which are applied to contralateral stylomastoid 45 canal' of said subject,
sides of the head. b. means for modulating an RF carrier signal with said AF
The circuit of FIG. 3, comprises five transistors 151-155, signal to produce a transdermal signal,
respectively; 21 resistors, reference numerals 161-181, c. means for balancedly applying said transdermal signal to
respectively; nine capacitors, 141-149, respectively; and one the facial nerve system of the subject at opposite sides of
transformer 19, appropriately interconnected by conductors the head at predetermined sites of the periaural and
in the manner shown in FIG, 3. In this version of an "auto 50 stylomastoid regions thereof,
matic carrier frequency controlled transdermal transmitter,' d. the applications of said amplified AF signal and of said
the transistors 15, 156, and 157 cooperate to form a constant transdermal signal being synchronous.
current differential amplifier which feeds the emitter followers 6. The apparatus of claim 5, further includes
of the transistors 153 and 154. These transistors 153 and 154 55 a. a pair of inductor means through which said transdermal
in turn feed a series resonant circuit, which includes the induc signal may be applied to the head of the subject.
tors 2 and 13 and the human head, itself, which is, of course, 7. The apparatus of claim 5, further characterized in that
disposed therebetween, as shown. In this manner, the head of a. said transdermal signal is applied to the head at peak LC
the subject functions as a capacitor, as should be understood. series resonance at the carrier frequency.
In accordance with the principles outlined hereinabove, at 60 8. The apparatus of claim 5, which is further characterized
resonant frequency of this circuit, the current within the cir in that
cuit peaks and the voltage drop across the resistor 164 a said means for balancedly applying said transdermal
becomes maximized. This maximum voltage across the re signal to the facial nerve system of the subject at opposite
sistor 164 is in turn fed to the base of the transistor amplifier sides of the head at predetermined sites of the periaural
152 and through a modulation network comprised of diodes 65 and stylomastoid regions thereof includes a pair of elec
92 and 93 and fed back to the input of the differential amplifi trodes, one of which is bare and the other of which is insu
er. Therefore, the transistors 152, 153, 154, 155, and 156, in lated. or
accordance with the principles of the invention, form an oscil 9. The apparatus of claim 5, further characterized in that
lator circuit, the frequency of which is determined by the in a means for amplifying said AF signal and introducing said
ductors 12 and 13, and instantaneous capacitance of the head 70 amplified signal to a region immediately adjacent the "ear
H. In this circuit, the resistor 74 provides a level adjustment. canal' of said subject, and said means for balancedly ap
As shown and as will be appreciated, the audio signal is in plying said transdermal signal to the facial nerve system
troduced into the circuit of FIG. 3 through the microphone 11 of the subject at opposite sides of the head at predeter
and is fed from a conventional hearing aid amplifier 100 to the mined sites of the periaural and stylomastoid regions
base of the emitter follower 151, which drives the above 75 thereofare housed within a frame means.
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10. The apparatus of claim 9, in which b. a second layer comprising a thin self-supporting film of
a. said frame means includes an eyeglass frame and temples, insulating material superimposed on said layer of conduc
b, said means for balancedly applying said transdermal tive material,
signal to the facial nerve system of the subject at opposite c. a third layer comprising a laminate of insulating film con
sides of the head at predetermined sites of the periaural ductive foil-insulating film superimposed on said self-sup
and stylomastoid regions thereof includes a pair of elec porting film and adapted to contact the skin of said sub
trodes mounted on inner surfaces of said temples. ject, and
11. The apparatus of claim 8, in which said insulated elec d. means maintaining said layers in unbonded surface con
trode comprises
a. a first layer comprising a layer of conductive material O tact with one another.
adapted to be directly connected to said signal source, t

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