FR2465474A1 - METHOD, MULTI-CHANNEL ELECTRODE, MULTI-CHANNEL RECEIVER AND MULTI-FREQUENCY DEVICE FOR ELECTRIC STIMULATION OF THE EAR - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS, A MULTI-CHANNEL ELECTRODE, A MULTI-CHANNEL RECEIVER AND A MULTI-FREQUENCY DEVICE FOR ELECTRICAL STIMULATION OF NERVES AND MUSCLES. RECEIVED SIGNALS ARE USED TO MODULATE HIGH FREQUENCY CARRIERS IN MULTIPLE CHANNELS 1, 2, 3, 4 AND THE MODULATED SIGNALS ARE INDUCTED BETWEEN AN EXTERIOR TRANSMITTER AND AN IMPLANTED MULTI-CHANNEL RECEIVER. AFTER THEIR DEMODULATION, THE SIGNALS ARE APPLIED TO A MULTI-CHANNEL STIMULATION ELECTRODE. THE INVENTION IS APPLIED IN PARTICULAR TO THE TREATMENT OF TOTAL OR PARTIAL DEAFNESS.

Description

The present invention relates to a method, an elec-

  multi-channel trunk, a multi-channel receiver and a multi-frequency device for

  electrical stimulation, and particularly to stimulating

  tion of nerves or muscles, for example to allow

  deaf or hard of hearing people to receive

  hearing; more particularly, the invention relates to

  leads to stimulation by electrical impulses.

  U.S. Patent No. 3,209,081 discloses a modification of standard hearing aid apparatus for the amplification of sound waves for implantation into the mastoid process. In this case, the implanted receptor is in direct contact with the bone by

  which the sound waves are transmitted to the inner ear.

by bone transmission.

  Recently appeared devices that do not rely simply on the amplification of sound waves, but

  on their conversion into electrical impulses. The impulses

  are used for electrical stimulation of the auditory nerve to produce auditory impressions in this way. U.S. Patent No. 3,449,768

  describes the use of coded pulse trains for

  to create an electric field with the desired gradients

  stimulation of the visual or acoustic system. The breed

  United States of America N 3 752 939 describes the use of

  an electrode whose surface carries two wires on

  all its length. This electrode is intended to be im-

  planted in the inner ear, in the ancient labyxinth

  TER AL. The article by Schindler et al. "Multielectrode Intracochlear Implants" in Otolaryngology Archive,

  Volume 103, December 1977, describes a local stimulation

  Spacially in the auditory nerve in cats. Clark and Hallworth's article "A Multiple-Electrode Array for Cocenlear Implant" in the Laryngology and Otolaryngology Journal 90/7, 1976, describes an electrode for

  the anterior labyrinth which has a pelvic structure

  Thin thin on a flat support made of flexible material. A

  provision has also been used including a

  thin threads for direct electrical stimulation

  auditory nerve after exiting the anterior labyrinth.

  Furthermore, European Patent Application No. 78,300,571 and German Patent Application DOS No. 2,823,798 disclose a multi-channel implantable hearing aid device based on electrical stimulation of the auditive nerve and using for this purpose

  circuits with active components.

  According to the invention, a device with multiple frequencies

  tiples for electrical stimulation by electri-

  multi-channel trode comprises: a transmission device

  mission to transmit several signals of

  each of which is modulated by a signal representing a frequency band, a multi-channel receiver

  intended to receive the transmitted signals, each channel of the receiver

  being associated with a signal representing the frequency band of a sound signal, and a device for

  apply the signal from each of the specific channels

  at least one electrode contact of the multi-channel electrode so that the latter provides a

electrical stimulation.

  Preferably, the invention relates to a device

  multi-frequency system to improve the stimulation of

  of the auditory nerve, which may include

  transcutaneous transmission channels whose frequencies

  The carrier quenches are modulated by repre-

  each one a frequency band of the audible range.

  A multi-channel receiver according to the invention essentially comprises: a plurality of independent channels each of which comprises a coil intended to receive a

  determined emitted signal, a demodulator connected to the

  and to demodulate the signal, and a device for applying the demodulated signals to the electrode contacts. These reception channels each receive

  signals transmitted wirelessly through the skin.

  The invention also relates to an electrode

  multiple channels intended to be implanted in the labyrinth

  anterior rinth and which comprises a molded piece and

  biologically compatible, within the

  what are several sons each ending in

  an electrode contact, the electrode contacts are

  on the surface of this piece and the wires being wavy

  to allow the electrode to be elastic and flexible.

  According to the invention, a method of producing such a multi-channel electrode consists in: a) producing several wires which carry a contact at their end; b) waving the wires to increase the flexibility of the body of the electrode; c) positioning these son in a mold and so that the contacts are held in position by depression; d) to fill the mold with a

biologically compatible material.

  According to the invention also, a method for improving

  electrical stimulation of the ear consists of:

  a) to emit several modulated signals corresponding to each

  cun to a frequency band inside the beach

  audible; b> to receive these modulated signals; (c) to demodulate

  ler the modulated signals; d) and to apply the signals

  demodulated to the multi-channel electrode that is implanted

in the fore labyrinth.

  Other features and advantages of the invention

  will appear in the course of the description which will

  to follow. In the accompanying drawings, given solely by way of non-limiting examples: FIG. 1 is a schematic section of a human ear, showing the positioning of the device according to the invention, FIG. 2 is a simplified electrical diagram

  of a preferred embodiment of a signal processor

  nals and external transmitter forming part of the

  multi-frequency positive to improve the

  Figure 3 is an electrical diagram of an embodiment of a multi-channel receiver

  part of the multi-frequency device for the improvement of

  electrical stimulation of the ear,

  Figure 4 schematically illustrates

  possible geometries of reception coils according to one embodiment of the invention,

  FIG. 5 shows a multi-channel electrode

  earlier labyrinth layers forming part of the

  multi-frequency stimulus enhancement

electric power of the ear,

  FIG. 6 schematically represents a labyrinthine

  the human foreground to illustrate the specificity of the pitch of the sound, the figures each indicating the frequency in Hertz which, in a given region of the length

  labyrinth, produces maximum activity in the

nerve breasts,

  FIG. 7 is a simplified section of an electrical

  multi-channel trowel of anterior labyrinth according to the invention, FIG. 8 is a perspective view of a mold intended for producing the electrode of FIG. 7,

  FIG. 9a represents another embodiment of

  According to the invention, FIG. 9b illustrates the introduction of the electrode of FIG. 9a, FIG. 10 is a simplified electrical diagram of a sound signal processor and external transmitter, the FIG. 11 is a circuit diagram of a preferred embodiment of a dynamic tape compression circuit of FIG. 10, and FIG. 12 is a circuit diagram of an embodiment of a transmitter of FIG. in the normal case, acoustic waves passing through the ear canal 10 reach the eardrum 12 which, in connection with the chain of ossicles 14 of the middle ear produces a movement of the latter which excites the previous labyrinth 16. The latter (or cochlea) is a snail shaped organ of about 2.5 turns. It comprises an upper channel 18 called vestibular ramp and a lower channel 20 called tympanic ramp. These

  two ramps are separated by cochlear laclee 22.

  Under the effect of incident acoustic waves,

  in the two ramps filled with a liquid from the bones

  of this liquid which, thanks to the function of

  version of the inner ear trigger electrical impulses; these impulses are driven to the brain by

  the acoustic nerve 24 and are interpreted as feelings

hearing.

  In people with sensory deafness

  the inner ear can no longer convert incident acoustic waves into electrical

  to transmit them to the brain. For this reason, the

  The invention therefore relates to a stimulation device for

  direct electrical stimulation of the anterior labyrinth

Eur.

  The device comprises a signal processor

  multi-channel and transmitter 30, which can be

  worn on the body. The transmitter is coupled with a receiver

  implanted. The coupling is preferably inductive,

  reading reels: '6 and 38 which are connected to the process-

  signal and transmitter 30 and coils 32

  and 34 which are part of the implanted receiver 39.

  As will appear in the detailed description

  which follows, the sound signal processor and transmits

  carrier 30 produces a plurality of carrier signals that are mod-

  by a series of signals from the audible frequency range. The emitted signals are picked up and demodulated by the implanted receiver. The demodulated signal is applied by the wires 42 and 44 to the multi-channel electrode 46 which is implanted in the anterior labyrinth. The electrode

  multiple channels has on its surface several

  electrode tacts that selectively produce a stimulus

  local labyrinth of the labyrinth according to the

frequency distribution.

  According to one embodiment of the invention, a dis-

  Multi-frequency Positive has four channels cor-

  responding to four frequency bands in l8

audible range.

  FIG. 2 is a simplified electrical diagram of an embodiment of a sound and transmitter signal processor which comprises four channels corresponding to the frequencies of 0.25 to 0.5 kHz, 0.5 to 1.0 kHz, 1 , 0 to 2.0 kHz

  and 2.0 to 4.0 kHz. The realization of each channel is

  lustrated as a simplified schematic for channel 1.

  Each channel comprises a band-pass filter 50 tuned to the desired frequency band (for example, 0.25 to 0.5 kHz for channel 1). The input of the filter 50 receives a sound signal from the microphone 52 and is amplified by a tuned amplifier 54. Behind the amplifier 54, the signal occupies a wide frequency band, as shown in, and after passing through the filter bandpass 50, the frequency range is limited as shown in 57. The channels for processing the lowest frequencies

  may include signal delay circuits,

  born to reproduce the delay in the normal ear resulting from the propagation of the progressive wave along the length

of the previous labyrinth.

  The signal 57 is then applied to a comparator 58 which delivers a clipped signal 59 whose passages through

  zero coincide with those of signal 57.

  The clipped signal 59 is applied to a voltage-to-voltage converter which delivers a variable DC voltage proportional to the frequency of the signal 59. The voltage-to-voltage converter comprises circuits

  appropriate, for example a monostable multivibrator de-

  latched by the signal 59 and which produces pulses of equal duration with the same repetition frequency as the

  signal pulses 59. The output of the multivibration circuit

  monostable transmitter is connected to a low-pass filter which de-

  delivers a variable DC voltage proportional to the

pulse frequency.

  The voltage signal at the output of the converter 60 is applied to a frequency voltage converter 62, for example a voltage-controlled oscillator whose output signal 63 consists of a pulse train of

  constant duration and whose repetition rate corresponds to

  to the control voltage of the oscillator.

  The repetition frequency of the signal pulses 63 may lie within a given band, between about 40 and 400 Hz, while the band-pass filter may

  filter a higher or lower frequency band.

  As will be explained in more detail below, the acoustic nerve responds best to repetition frequencies of the stimulation signal of less than about 400 Hz. For this reason, the bandpass filter-filtered frequency band is transformed. as described above in a lower frequency band better adapted to the acoustic nerve. This band is in many cases between 40 and 400 Hz, but can be

  also considerably more important.

  The signal at the output of the bandpass filter 50 is

  also applied to a diode 66 in series with an amplifier

  logarithmic indicator 68 to produce a

  which is logarithmically dependent on 12 am-

  amplitude of the signal rectified by the diode 66.

  All channels carry the same sets of devices to override the different pass-by-pass filters In each channel, the monostable multivibrator circuit produces

  output pulse trains with pulse durations

  variables9 whose repetition frequency varies

  be 40 and 400 HZD depending on the frequency band and

  which is particularly adapted to the evaluation of the lab-

  These impulse trains modulate the horn signals in the 7k emitter

  In the present embodiment of four

  In this context, the multi-channel channel uses four carrier signals, two to twelve 1 Hz, and the other two

  31? .5z o The pulses of channels 1 and 3 are used

  to modulate the carrier signals at 12 / is and the pulse trains of channels 2 and 4 modulate the signals

  carrier signals at 31 l.HZ.o The carrier signals that are mod-

  1 and 2 are applied to a transmitter coil and the carrier signals which are modulated to the signals of the channels 3 and 4 are applied.

  The two frequencies of

  which are applied to a resignation coil are

  also different, thus avoiding any

  Mutual fluence between channels The use of a single transmit coil for two channels is described as a simplification. But another possible way, if advantageous, is to

  use a single transmit coil for each channel.

  Figure 3 illustrates the layout of a preferred period.

  A multi-channel receiver is planned for four channels. Each channel has an 81-84 coil, the coils

  81 and 82 being inductively coupled to the transmitter coil

  76 and the coils 83 and 84 being coupled by inductive

  with the transmitting coil 78. Each receiver unit

  81-84 is connected in parallel with a capacitor

  to form an oscillating circuit whose frequency

  quence of resonance is 12 or 31 MEz.

  The signal from coil 81 is applied to

  a demodulator constituted by a diode 86, a capacitor

  87 and a resistor 88. In the case of using a modulation and demodulation by pulse duration it is possible to connect a zener diode bypass on the resistor 88 in order to limit the voltage at the output

  of the detector. This minimizes variations in

  of tension resulting from coupling variations between

  the transmitting and receiving coils.

  The voltage at the output 90 of a detector is

  preferably between 0 and 3 volts, with a frequency of

  between 40 and 400 Hz, depending on the modula-

tion.

  In particular for a device intended to

  tissue with a small number of inde-

  pendents between them, auques are applied at the same time

  different signals, and more particularly for a

  positive with 2 to 9 channels, the following procedure can be

  applied with advantage: In order to reduce the clutter

  required by the use of a number of receiver coils, these coils overlap and are

arranged in groups.

  Although each receiver coil within a group is tuned to a particular frequency,

  if the mutual induction between two or three coils

  leads to a crosstalk of unacceptable intensity.

  Ceptable, the coils are simply arranged one above the other. If we have the reels as the

  shows Figure 4 in order to compensate for their magnetic flux.

  mutual influence, their mutual inductance may be canceled.

  This makes it possible to obtain two or three channels each time independent of each other with a NEXT crosstalk.

  glaring, occupying barely more space than the

  required for a single channel. This concept is illustrated in FIG. 4 which shows the arrangement of the coils 81, 82 and 83, 84 of two groups separated from each other, thus giving an idea of the various possibilities of arranging the

  two groups with two coils each to compensate for the induc-

  mutual assistance. References 85a, 86a, 87a designate three

  associated coils of a group with inductive compensation

  mutual assistance. The diameter of each coil is of the order of 15 to 20 mm and the distance between two groups of coils is of the order of 30 mm in order to eliminate the crosstalk

between groups.

  Since the coils 81 and 82 are tuned to different frequencies (for example 12 and 31 1Hz), each receive channel only receives and demodulates the

  signal of the associated transmission channel. The demodulated signal

  from each receiving channel is applied to an elec-

  multi-channel trunk, as shown in Figure 5. Each channel can be connected to one or more

  electrode contacts 92 which are arranged according to the.

  length of the electrode body, which stimulates

  specific regions of the length of the labyrinth

  for the desired improvement of auditory perceptions

tives.

  With regard to the different patterns of connection

  xion, it is possible to use bipolar stimulation, unipolar stimulation with respect to a distant-earth electrode, or stimulation with respect to a mass

common distributed.

  The multi-channel electrode consists of an elongated silicon silicone elastomer shaped body, for example Silastic, in which several wires, designated 91, are placed. Each wire ends with a contact ball 92 located on the surface of the body. 90 of the electrode. The

  contacts are arranged on the surface of the electrode of

  nese that after implantation of the latter in the labyrinth, it is possible to selectively stimulate particular regions. As shown in Figure 6, which is a diagrammatic representation of an earlier human labyrinth, the high-frequency areas are in the base area and the high-frequency areas are in the area.

  Summit. It is thus possible to provoke the perception

  the sound of the desired heights by the positioning of the contacts 92 of the electrode inside the labyrinth

  prior. Thanks to the additional variation of the frequency

  stimulation, it is possible to obtain a spectrum

continuous sound.

  Fig. 7 is a schematic sectional view of the multi-channel electrode showing the arrangement of wires 93 and 94 within the electrode. Only two sons have been represented for simplicity. Each wire is corrugated to increase its longitudinal elasticity, which increases

  the flexibility of the electrode when it is introduced

in the labyrinth.

  In a preferred embodiment, the yarns are platinum (90%) iridium (10%), Teflon insulated, and 25 microns in diameter. The balls at the ends of the wires have a diameter of 0.3 mm on average and are formed by the

fusion of the threads in a flame.

  The contact balls are arranged in pairs in two rows facing each other along the length of the body of the electrode. According to one embodiment, the largest diameter

  of the electrode is 0.9 mm and decreases towards the tip

  than 0.5 mm. The total length of the electrode must correspond to

  lay at its location in the labyrinth on a long

from 20 to 25 mm.

  Figure 8 represents one of the two halves

  96 of a mold intended for the manufacture of electricity

  multi-channel trode. It has a groove

  narrow 97 corresponding to the desired shape of the electrode.

  In the groove are several holes 98 which are 1 1 all connected to a suction duct 99. To manufacture

  the multi-channel electrode, the wires are first

  positioned in the groove of the half-mold, and the ball-shaped ends of these son are held in the holes 98 by depression. Then, the mold is closed and plastic, for example Silastic, is injected into the groove 97. The vacuum transmitted through the holes 98 holds the contacts of the electrode in position

* exact on the surface of the body of the electrode.

  FIG. 9a illustrates a variant embodiment

  of the electrode 100 which is formed with a corresponding curvature

laying on that of the labyrinth.

  Figure 9b illustrates a method of introducing

  this electrode in the previous labyrinth. A stem

  Figure 102, for example a steel rod, is placed inside the electrode and is slowly extracted while the electrode enters the labyrinth. So,

  the electrode 100 returns to its original shape.

  Other possible configurations not yet mentioned external and implanted subassemblies are:

  1) a four or more channel electrode introduced

  in the previous labyrinth and connected to a

  4-channel implanted system and a signal processor

sound and one-channel transmitter.

  In this case, an electrode channel is selected for stimulation, or any number of contacts of the electrode are interconnected. In the latter case, it is possible by a corresponding adapter to compensate

  the different thresholds of the various electrode contacts.

  2) An electrode with a channel at the round window or in its vicinity, fixed in connection with a larger

  mass electrode, also placed outside the

  byrinth, can be used with a single-channel device and a sound signal processor and

external transmitter to a channel.

  The set described under 1) has already been tried on some selected volunteers with total deafness, and it allows, without additional reading on the lipsq

  electro-stimulation only, to obtain an understanding of

  speech clear 60 to 70ej for unknown words or phrases. This shows that this prosthesis can already provide valuable assistance to people with deafness .. However, the set described under 2) is intended for people who are not totally deaf,

  but rather for people with high levels of

and hearing-impaired children.

  Both in the one-channel and multi-channel embodiments of the external processor of

  sound and transmitter signals, it is possible to

  firing sound waves not in-of pulse trains

  but in analog signals. In this case, it is necessary to

  see an appropriate compression of the dynamic range and

  compensation for the dependence-between loudness-

  and the frequency, very important characteristics of the

  ceasing of sound signals and transmitter. These two characteristics

  These are very important because the dynamic range between the stimulation intensity needed to produce an auditory impression and that necessary to produce a too strong impression is much smaller than in the acoustics of the ear. normal, and complicates

  addition in many cases because the threshold and the

  sound intensity above the threshold depend on

  strongly of the stimulation frequency.

  Dynamic range compression is preferentially

  this to a nonlinear function. This nonlinear function can be a logarithmic function, a function of a certain power or a function with linear segments

  or any other appropriate form.

  This non-linearity can be obtained preferably

  by means of a differential amplifier or amplifier

  operational indicator operating with a diode network

  or with transistors connected in diodes.

  In order to reduce the production of unwanted frequencies by compression of the dynamics, it is

  It is possible to control the non-linearity by a de-

  stalled in frequency. In this case, the products of distortion

  order can be eliminated from the frequency signal.

  This is shifted upward by a narrow-band high-frequency band-pass filter before the signal is returned to its original range of possible frequencies. Another possibility for reducing distortion products is to use several non-linearity functions within bands of the width of the

  octave. It is also possible to use an amplification

  set with sufficient time constants

  on the ascent and descent, from two to ten

  seconds or 100 to 300 milliseconds. The characteristic

  that amplitude of this amplifier makes it possible to obtain the

  desired form by the introduction of non-linearity

  propriety in the signal circuit.

  The dynamic range compression circuit may also be connected to the frequency response compensation circuit. In this case, it is understood that

  the value of the necessary compensation for frequency response

  quence is reduced, but it must be very precise.

  Figure 10 is a simplified schematic of a process

  sound signals to one or more channels associated with a transmitter. A multi-channel stimulator consists of several substantially identical channels each with its own high frequency conversion. Each channel is adapted to a determined voice frequency band which is filtered by a respective band filter. In the

  case of a single-channel pacemaker, only one of these

  Naux is provided and therefore the band filter 103 can be eliminated. The signal received from an electret microphone 104 occupies a dynamic range of more than 80 dB. The

  transformation of this broad dynamic range for the

  lead in the admitted intensity range of stimulation of

  the order of 10 dB is achieved with the help of a dynamic compressor.

  107 which will be described in detail later, and / or a regulation controlled by the input, acting on

  the adjustable amplifier 105. Compared to the

  dynamic pressure with non-linear elements, the

  This advantage has the advantage of the low momentary nonlinear distortion, but the final rise time allows the passage of spurious pulses at the moment of noisy signals appearing suddenly, so that in general dynamic compression is also used.

although a regulation.

  The circuit 106 intended to adapt the frequency response

  the dependence between the previously measured frequency

  The constant sound power curves of the patient include frequency-dependent elements, for example RC or LC circuits. This circuit is realized in a common way. In principle, it can be connected behind the dynamic compression circuit 107 in which case an influence of the low frequency, but nevertheless very precise, is sufficient. By means of an amplitude modulated transmitter 108 associated with an output circuit 109, the transmitted signal is transmitted to the receiver circuit 110

  implanted, and the demodulator 111 and from there, it is applied

than at the electrode 112.

  Figure 11 shows the circuit used for the

  dynamic compression. It essentially comprises a cir-

  Integrated Cooking System 112 (TL 441) consisting essentially of

  four differential amplifiers attacked by divisions

  different attenuation voltage and whose outputs are connected in parallel. The output voltage, which appears as a differential voltage between points 122 and 123 (y or y), was logarithmically

  input voltage at point 121. This voltage of

  is applied to the input 124 of the circuit 112 by the

  capacitor 113 which blocks the possible DC voltage.

  Resistor 120 sets the DC voltage level at input 124 of the circuit. Differential voltage between

  points 122 and 123 are demodulated in the usual way

  in a single-phase voltage by an op-

  rational 1i4 which constitutes a subtractor circuit with the resistances 115,116,117 and 118. -A potentianètre 119 penret

  to balance the offset voltage.

  FIG. 12 is a diagram of the modulator transmitter

  amplitude. This transmitter has an oscillator which produces the carrier frequency of 12 MHz. and one

  final power stage. The output circuit 126 constitutes

  kills a band filter with the receiver circuit 127 im-

  planted, tuned to the same frequency. A current driven, high input resistance band filter produces for a determined coupling, called critical coupling, a maximum induced voltage in the secondary circuit. In the vicinity of this fixed point, secondary induced voltage

  therefore, little depends on the coupling. With the inductive coupling

  tif used in this case, the tolerances on the gap

  between the transmitting coil and the receiver coil,

  critical coupling, can be very advantageous.

  his. Thanks to these overvoltage factors chosen from the

  As much as possible, a "critical range" of about 10 to 12 mm can be obtained. For a diameter of the transmitting coil of 23 mm and a deviation of + 10 mm, the

  secondary voltage only varies by -5%.

  Since the saturation of the tran-

  output sistor 129, because of the high overvoltage factor of the transmitter circuit, the collector modulation can not be used for the amplitude modulation, and it is necessary to use either the modulation of the emitter current or

  base modulation (as in the present example).

  The modulation voltage is applied to the base by

  the resistor 133, the coupling coil 134 and the resistor

  130. The latter is chosen according to the

  power output required and allows to set exact-

  the control power at high frequency without

  It is difficult to modify the number of turns in the coupling winding 134. The capacitors 131 and 132 connect the modulation input and the supply voltage to the high frequency ground. The Schottky diode 128 prevents parasitic oscillations from occurring in the case of accidental saturation of the transistor of

exit.

  The output circuit 126 of the transmitter is mounted on

  an ear piece in "Plexiglas" and can therefore be

  precisely positioned above the implanted receiver coil. The entire transmitter is miniaturized so that it

  can also be positioned on this ear piece.

  This has the advantage of reducing the radiation of electromagnetic waves because the length of all the high frequency conductors is less than 20 mm and they can not

behave on the air

  The described method of electrical stimulation of the ear by means of a multi-frequency device according to the invention makes it possible to improve the hearing faculties

  people with deafness and

  people with severe hearing problems.

  The distribution of sound signals in bands

  and the selective stimulation of different regions

  the inner labyrinth improves the quality and

  comprehensibility of auditory perceptions. The circuit

  implanted ceptor composed exclusively of components

  passive electronics, does not consume energy and suffices

  did the stimulation signals themselves go through the

  skin to be transmitted inside the body.

  The hearing aid, comprising the

  multi-channel cochlea can be easily manufactured

  and the manufacturing process ensures exact positioning

  te electrode contacts to get the desired perceptions of pitch of the sounds by the stimulation of the labyrinth

prior.

  A modulation of duration of impulse is used in

  the described embodiment, but it is also possible

  to use other modulation methods, for example

  amplitude or frequency modulation.

  After appropriate electronic processing,

  analogical nals of stimulation can also be

  used in the form of pulsed signals or digital signals.

  c. In the described digital embodiment, the audible frequency bands are converted into bands

  corresponding signals between 40 and 400 Hz but the

  corresponding signals, both in numerical form and

  that in analog form, can be located in the same

  frequency range from that of the audible frequencies.

Claims (22)

  1 - Electronic stimulation and reception set   including a receiver which itself has a   multi-channel electrode, characterized in that   carries a transmission device (32,34,36,38) for transmitting a plurality of carrier signals each of which   is modulated by a signal that represents a frequency band   which are intended to be received by that   receiver (39), each channel of the receiver being associated with a signal representing the frequency band of a sound signal, and a device (42, 44) for applying the signals   from each of the aforementioned channels to at least one   electrode tact of the multi-channel electrode (46) so that said multi-channel electrode provides electrical stimulation.   2 - Set according to claim 1, characterized   in that it is intended for electrical stimulation of the ear, said frequency bands being in the audible range and said electrode (46) being   multiple channels being implanted in the labyrinth laughing in the ear.   3 - assembly according to claim 1, characterized   in that said multi-channel receiver (39)   door channels independent of each other for ter the received signals.   4 - Set according to claim 2, characterized   in that each of the independent channels comprises a receiving coil (81-84) tuned and a demodulator of signals (86, 87, 88).   An assembly according to claim 2, characterized in that said electrode (46) comprises an elongated and biologically compatible molded body (90), and on the inside thereof   which there are several threads (91), each thread is   by an electrode contact (92) and the contacts   electrode located on the surface of the body.   6 - assembly according to claim 5, characterized   in that each wire (93, 94) is corrugated according to the length   molded body, so as to increase the flexibility of the body for its introduction into the labyrinth Ear of the ear.   7 - assembly according to claim 5, characterized   in that said electrode contacts (92) are posi-   in order to produce a stimulation corresponding to the arrangement of the frequencies in the anterior labyrinth.   8 - The assembly of claim 2, characterized   characterized in that said transmission device comprises a plurality of channels, said frequency bands lying within the band of audible frequencies, each channel comprising a band-pass filter (50) for filtering a frequency band, a generator of pulse (58) means (66) connected to said filter for detecting the signal frequencies of said bandpass filters and for controlling the frequency of said pulse generator, the transmitting device further including a device (60,62)   by which the amplitude of the signal at the output of the filter passes   band controls the pulses of said pulse generator   and a transmitter (74) for modulating a carrier signal.   with the signal at the output of the said pulse generator   sions. 9 - An assembly according to claim 8, characterized in that said pulse generator (58) consists of a monostable multivibrator circuit, said device (60, 62) which detects the amplitude of the signal controlling the duration of the pulses.   An assembly according to claim 8, characterized in that said channels cover the bands from 0.25 to   0.5 kHz, 0.5 to 1.0 kHz, 1.0 to 2.0 kHz and 2.0 to 4.0 kHz.   11 - The assembly of claim 8, characterized   in that said multi-channel receiver comprises four channels, each of which comprises a coil (81, 84), said transmitter (74) comprising two coils (76, 78) whose   each receives two modulated carrier signals, from   that two of the said reception coils are   by induction with one of said transmitting coils   and that the other two receiving coils are 1   by induction with the other of said coils of if we.   12 - The assembly of claim 11, characterized   in that said first two receive coils are   (81, 82) and the other two receiving coils (83, 84) overlap, so as to   to minimize the mutual inductance between bines.   13 - assembly according to claim 1, characterized   in that said transmitter (74) comprises at least one   coil for transmitting said modulated signals, said receiver   having a plurality of coils (81-84) whose number corresponds to the number of channels of said receiver, said   emission coil being inductively coupled with the said receiving coils.   14 - An assembly according to claim 2, characterized   in that said transmitter comprises several channels, said frequency bands being in the audible frequency range, each channel comprising a band-pass filter (L03) for filtering a frequency band in the audible frequency range, a device Dynamic range compression device (106), a sound intensity dependent frequency compensation device (106) and a transmitter (108) for modulating a carrier signal with the analog sound signal treaty.   Assembly according to claim 14, characterized   characterized in that said multi-channel receiver   carries four channels each of which comprises a coil (81 -   84), said transmitter comprising two coils (76, 78) whose   each receives two modulated carrier signals, two des-   said receiving coils being inductively coupled with one of said transmitting coils and the other two receiving coils being inductively coupled with   the other of said transmitting coils.   16 - The assembly of claim 15, characterized   in that said first two receive coils are   overlap and said two other spools of   2o ception also overlap, so as to reduce   minimum mutual inductance between said coils.   17 - An assembly according to claim 15, characterized   in that this dynamic-range compression is ensured by providing appropriate non-linearity, for   example with electrical components of characteristic curve nonlinear risk.   19 - The assembly of claim 17, characterized   in that said non-linearity is provided by a logarithmic amplifier.   19 - The assembly of claim 15, characterized   in that said dynamic range compression is produced by first shifting the frequency of the signal upward, by shifting this shifted frequency by a   logarithmic amplifier, and then reducing the frequency   quence offset to its initial value.   Assembly according to claim 15, characterized   in that said dynamic range compression is provided by non-linearity provided in the width of an octave.   21 - assembly according to claim 15, characterized   in that said dynamic range compression is   ensured by a regulated amplifier.   22 - The assembly of claim 14, characterized   in that each channel of said transmitter comprises an amplifier   unsaturated powerplifier with base modulation.   23 - An assembly according to claim 14, characterized   in that each channel of said transmitter comprises an amplifier   unsaturated power booster with modulation by the transmitter.   24 - The assembly of claim 14, characterized   in that each channel of said transmission device   sion has a band-pass filter consisting of the cir-   cooked output of the transmitter and the receiving circuit tuned.   Assembly according to claim 24, characterized   in that said bandpass filter is critically coupled tick.   26 - An assembly according to claim 15, characterized   characterized in that said transmitter is mounted on a hook   ear that also supports the transmit coil.   27 - An assembly according to any one of the   cations 14 to 26, characterized in that, to avoid a distribution of the audible signals into several channels, these   signals are applied to one of the transmission channels.   28 - Method for manufacturing a multi-channel electrode for use in a next set   any one of claims 1 to 27, comprising a   an elongated and biologically compatible shaped body (90) within which there are several wires (91), each wire terminating in an electrode contact (92) and the electrode contacts on the surface of said body, the method characterized in that it essentially consists in preparing a plurality of threads (91) which carry a contact (92)   at their end, to wave said wires so as to increase   Maintain the flexibility of the body of the electrode, to position   said wires in a mold (96) so that said   tacts are held in position by depression, and   filling said mold with a biologically compatible material cally.