BIMODAL HEARING PROSTHESIS
A bimodal hearing prosthesis for rehabilitating the hearing of a recipient. The hearing prosthesis comprises: a sound processing unit configured to process a received sound signal; and an implantable bimodal stimulation system, comprising: a mechanical stimulation arrangement configured to generate waves of fluid motion in a recipient's inner ear fluid based on the processed sound signal; an electrode assembly configured to deliver electrical stimulation signals generated based on the processed sound signal to a recipient's cochlea.
The present application is a National Stage Application of International Application No. PCT/US2009/038937, filed Mar. 31, 2009, and claims the benefit of U.S. Provisional Patent Application 61/041,185; filed Mar. 31, 2008. The contents of these applications are hereby incorporated by reference herein.
BACKGROUND1. Field of the Invention
The present invention is generally directed to a hearing prosthesis, and more particularly, to a bimodal hearing prosthesis.
2. Related Art
Hearing loss, which may be due to many different causes, is generally of two types, conductive and sensorineural. In some cases, an individual may have hearing loss of both types. In many people who are profoundly deaf, however, the reason for their deafness is sensorineural hearing loss. Sensorineural hearing loss occurs when there is damage to the inner ear, or to the nerve pathways from the inner ear to the brain. As such, those suffering from sensorineural hearing loss are thus unable to derive suitable benefit from conventional acoustic hearing aids. As a result, hearing prostheses that deliver electrical stimulation to nerve cells of the recipient's auditory system have been developed to provide persons having sensorineural hearing loss with the ability to perceive sound. Such electrically-stimulating hearing prostheses deliver electrical stimulation to nerve cells of the recipient's auditory system.
As used herein, the recipient's auditory system includes all sensory system components used to perceive a sound signal, such as hearing sensation receptors, neural pathways, including the auditory nerve and spiral ganglion, and parts of the brain used to sense sounds. Electrically-stimulating hearing prostheses include, for example, auditory brain stimulators and cochlear™ prostheses (commonly referred to as cochlear prosthetic devices, cochlear implants, cochlear devices, and the like; simply “cochlear implants” herein.)
Most sensorineural hearing loss is due to the absence or destruction of the cochlea hair cells which transduce acoustic signals into nerve impulses. It is for this purpose that cochlear implants have been developed. Cochlear implants electrically stimulate a recipient's cochlea by directly delivering direct electrical stimulation signals to the auditory nerve cells, thereby bypassing absent or defective hair cells that normally transduce acoustic vibrations into neural activity. Such devices generally use an electrode array implanted in the cochlea so that the electrodes may differentially activate auditory neurons that normally encode differential pitches of sound.
In contrast to sensorineural hearing loss, conductive hearing loss occurs when the normal mechanical pathways used to provide sound to hair cells in the cochlea are impeded, for example, by damage to the ossicular chain or to the ear canal. Individuals who suffer from conductive hearing loss typically have some form of residual hearing because the hair cells in the cochlea are undamaged. As a result, individuals suffering from conductive hearing loss typically receive an acoustic hearing aid. Acoustic hearing aids stimulate an individual's cochlea by providing an amplified sound to the cochlea, where the amplified sound causes mechanical motion of the cochlear fluid.
Unfortunately, not all individuals who suffer from conductive hearing loss are able to derive suitable benefit from hearing aids. For example, some individuals are prone to chronic inflammation or infection of the ear canal and cannot wear hearing aids. Similarly, hearing aids are typically unsuitable for individuals who have malformed, damaged or absent outer ears, ear canals and/or ossicular chains.
SUMMARYIn one aspect of the invention, a bimodal hearing prosthesis for rehabilitating the hearing of a recipient is provided. The hearing prosthesis comprises: a sound processing unit configured to process a received sound signal; and an implantable bimodal stimulation system, comprising: a mechanical stimulation arrangement configured to generate waves motion in a recipient's inner ear fluid based on the processed sound signal; an electrode assembly configured to deliver to the recipient's cochlea electrical stimulation signals generated based on the processed sound signal.
In another aspect of the invention, a method for rehabilitating the hearing of a recipient with a bimodal hearing prosthesis comprising an implantable electrode assembly configured to electrically stimulate a recipient and an implantable mechanical stimulation arrangement configured to directly mechanically stimulate the recipient's inner ear by generating waves of fluid motion in the recipient's inner ear fluid is provided. The method comprises: receiving an acoustic sound signal; processing the acoustic sound signal; generating one or more of electrical stimulation signals and mechanical stimulation signals, based on the processed acoustic sound signal; and stimulating the recipient's inner ear using the generated stimulation signals.
In a still other aspect of the present invention, a bimodal hearing prosthesis for rehabilitating the hearing of a recipient is provided. The prosthesis comprises: means for receiving an acoustic sound signal; means for processing the acoustic sound signal; means for generating one or more of electrical stimulation signals and mechanical stimulation signals, based on the processed acoustic sound signal; and means for stimulating the recipient's inner ear based on the generated stimulation signals
Illustrative embodiments of the present invention are described herein with reference to the accompanying drawings, in which:
Aspects of the present invention are generally directed to a hearing prosthesis configured to selectively electrically and/or mechanically stimulate a recipient's cochlea. Such a hearing prosthesis, referred to herein as a bimodal hearing prosthesis, comprises an electrode assembly configured to be implanted in a recipient's cochlea, and a mechanical stimulation arrangement. The electrode assembly delivers electrical stimulation signals to the cochlea, while the mechanical stimulation arrangement bypasses the recipient's outer and middle ears to directly generate waves of fluid motion in the recipient's inner ear. In certain embodiments, the mechanical stimulation arrangement is configured to be positioned adjacent the inner ear and may comprise, for example, a middle ear or inner ear mechanical stimulator. In other embodiments, the mechanical stimulation arrangement is a bone conduction device.
Also shown in
Each of the semicircular canals 125 is filled with a fluid known as endolymph, and contains a tiny hairs (not shown) whose ends are embedded in a gelatinous structure known as the cupula (also not shown). As the individual's head 100 twists in various directions, the endolymph moves into different sections of semicircular canals 125. The hairs detect when the endolymph passes thereby, and a signal is then sent to the brain. Therefore, using the hair cells, horizontal canal 126 is able to detect horizontal head movements, while the superior 128 and posterior 127 canals are able to detect vertical head movements.
The details of cochlea 140 are described next below with reference to
Referring to
Cochlea 140 spirals about modiolus 154 several times and terminates at cochlea apex 146. Modiolus 154 is largest near its base where it corresponds to first turn 151 of cochlea 140. The size of modiolus 154 decreases in the regions corresponding to medial 152 and apical turns 156 of cochlea 140.
Referring now to
Portions of cochlea 140 are encased in a bony capsule 170. Bony capsule 170 resides on lateral side 172 (the right side as drawn in
Sound entering auricle 110 causes pressure changes in cochlea 140 to travel through the fluid-filled tympanic and vestibular canals 138, 134. As noted, organ of Corti 150 is situated on basilar membrane 158 in cochlear duct 136. It contains rows of 16,000-20,000 hair cells (not shown) which protrude from its surface. Above them is the tectoral membrane 162 which moves in response to pressure variations in the fluid-filled tympanic and vestibular canals 138, 134. Small relative movements of the layers of membrane 162 are sufficient to cause the hair cells to send a voltage pulse or action potential down the associated nerve fiber 178. Nerve fibers 178, embedded within spiral lamina 182, connect the hair cells with the spiral ganglion cells 180 which form auditory nerve 114. Auditory nerve 114 relays the impulses to the auditory areas of the brain (not shown) for processing.
The place along basilar membrane 158 where maximum excitation of the hair cells occurs determines the perception of pitch and loudness according to the place theory. Due to this anatomical arrangement, cochlea 140 has characteristically been referred to as being “tonotopically mapped.” That is, regions of cochlea 140 toward basal region 116 (
The fluid in tympanic and vestibular canals 138, 134, referred to as perilymph, has different properties than that of the fluid which fills cochlear duct 136 and which surrounds organ of Corti 150, referred to as endolymph. As described above with reference to
Internal component 244 comprises an internal receiver unit 232, a stimulator unit 220, and a bimodal stimulation system 280. Bimodal stimulation system 280 comprises an elongate electrode assembly 248 and a mechanical stimulation arrangement 215. Internal receiver unit 232 comprises an internal coil 236, and preferably, a magnet (also not shown) fixed relative to the internal coil. Internal receiver unit 232 and stimulator unit 220 are hermetically sealed within a biocompatible housing, sometimes collectively referred to as a stimulator/receiver unit.
In the illustrative embodiment of
As noted, internal component 244 further includes a bimodal stimulation system 280. As shown, bimodal stimulation system 280 comprises an electrode assembly 248 which is configured to be implanted in cochlea 140. Electrode assembly 248 comprises a longitudinally aligned and distally extending array 245 of electrodes 246, sometimes referred to as electrode array 245 herein, disposed along a length thereof. Although electrode array 245 may be disposed on electrode assembly 248, in most practical applications, electrode array 245 is integrated into electrode assembly 248. As such, electrode array 245 is referred to herein as being disposed in electrode assembly 248. The proximal end of electrode assembly 248 is electrically connected to a lead 262 extending from stimulator unit 220. As described below, in embodiments of the present invention, stimulator unit 220 generates, based on data signals received at receiver unit 232, electrical stimulation signals which are delivered to electrode assembly 248 via lead 262. The stimulation signals are applied by electrodes 246 to cochlea 140, thereby stimulating auditory nerve 114.
As described in greater detail below, in embodiments of the present invention, electrode assembly 248 is implanted at least in basal region 116 of cochlea 140, and sometimes further. For example, electrode assembly 248 may extend towards apical end of cochlea 140, referred to as cochlea apex 134. In certain circumstances, electrode assembly 248 may be inserted into cochlea 140 via a cochleostomy 122. In other circumstances, a cochleostomy may be formed through round window 121, oval window 112 (
Electrode assembly 248 may comprise a perimodiolar electrode assembly which is configured to adopt a curved configuration during and or after implantation into the recipient's cochlea. In one such embodiment, electrode assembly 248 is pre-curved to the same general curvature of a cochlea. Electrode assembly 248 is held straight by, for example, a stiffening stylet (not shown) which is removed during implantation so that the assembly adopts the curved configuration. Other methods of implantation, as well as other electrode assemblies which adopt a curved configuration may be used in alternative embodiments of the present invention.
In other embodiments, electrode assembly 248 comprises a non-perimodiolar electrode assembly which does not adopt a curved configuration. For example, electrode assembly 248 may comprise a straight assembly or a mid-scala assembly which assumes a mid-scala position during or following implantation.
As shown in
In the illustrative embodiment of
Stimulation arrangement 215 comprises an actuator 240 electrically connected to stimulator unit 220 by lead 264, a stapes prosthesis 254 and a coupling element 253. As described in greater detail below with reference to
Although the embodiments of
Sound input element 324 receives a sound signal 301 and generates an electrical output signal 303 representing the sound. Electrical signal 303 is provided to sound processing unit 326 which converts the signal into encoded data signals which may be transmitted to internal component 344. More specifically, in the illustrative embodiment of
Electrical stimulation processor 352 processes signal component 305 to generate a processed electrical signal 309 representing the high frequency components of sound signal 301. Similarly, mechanical stimulation processor 354 processes signal component 307 to generate a processed electrical signal 311 representing the low frequency components of sound signal 301. Signals 309, 311 are then provided to transmitter unit 328 where the signals are encoded and transmitted to receiver unit 332 in internal component 344. Internal receiver unit decodes the transmitted signals, and provides electrical signals 309, 311 to stimulator unit 320.
Based on electrical signals 309, 311, stimulator unit 320 generates stimulation signals which are provided to one or more components of bimodal stimulation system 380. As shown, bimodal stimulation system 380 comprises an electrode assembly 318 and a mechanical stimulation arrangement 315. Stimulator unit 320 comprises an electrical stimulation signal generator 356 configured to generate electrical stimulation signals 319 based on electrical signals 309. Electrical stimulation signals 319 are provided to electrode assembly 318 for delivery to the recipient, thereby stimulating auditory nerve 114 (
Stimulator unit 320 further comprises actuator drive components 358. Based on signal 311, actuator drive components 358 generate stimulation signals 321 which are provided to mechanical stimulation arrangement 315. Stimulation signals 321, sometimes referred to herein as actuator drive signals 321, cause vibration of an actuator within mechanical stimulation arrangement 315. As described above, in certain embodiments the actuator is coupled to the recipient's inner ear, the vibration is transferred to the inner ear fluid, thereby evoking a hearing percept by the recipient. In other embodiments, the actuator is a positioned to deliver vibration to the recipient's skull. For example, the actuator may be part of an externally worn bone conduction device, or an implanted bone conduction device.
Although the embodiments of
Similarly, bimodal hearing prosthesis 300 has been described above with reference to a preprocessor 350 which filters electrical signal 303 based on the frequency of received sound signal 301. It should be appreciated that preprocessor 350 may also filter electrical signal 303 using alternative criteria, signal characteristics, etc. For example, in certain embodiments, preprocessor 350 may allocate the entirety of electrical signal 303 to electrical stimulation processor 352 or mechanical stimulation processor 354.
Stimulation arrangement 415 comprises an actuator 440 coupled to a stimulator unit (not shown) by a lead or cable 428. Actuator 440 may be positioned and secured to the recipient by a fixation system. Exemplary fixation systems that may be used to secure actuator 440 to the recipient are described in commonly owned and co-pending U.S. patent application Ser. No. 12/349,495 entitled “MECHANICAL SEMICIRCULAR CANAL STIMULATOR,” and commonly owned and co-pending U.S. patent application Ser. No. 12/349,502 entitled “MECHANICAL SCALA TYMPANI CANAL STIMULATOR,” the contents of both are hereby incorporated by reference herein in their entirety.
In the embodiments of
To implant stimulation arrangement 415, a surgeon may drill or form a passageway in the mastoid of the skull. This passageway is preferably constructed and arranged such that it provides direct access to the cochlea. In this embodiment, the surgeon then drills or forms an opening in one of the recipient's semicircular canals 125 (
Stimulation arrangement 515 comprises an actuator 540 coupled to a stimulator unit (not shown) by a lead or cable (not shown). Actuator 540 may be positioned and secured to the recipient by a fixation system. Exemplary fixation systems that may be used to secure actuator 540 to the recipient are described in commonly owned and co-pending U.S. patent application Ser. No. 12/349,495 entitled “MECHANICAL SEMICIRCULAR CANAL STIMULATOR,” and commonly owned and co-pending U.S. patent application Ser. No. 12/349,502 entitled “MECHANICAL SCALA TYMPANI CANAL STIMULATOR,” the contents of both are hereby incorporated by reference herein in their entirety.
Stimulation arrangement 515 further comprises a stapes prosthesis 554. As shown in
Connecting actuator 540 and stapes prosthesis 554 is a coupler 509. In the illustrative embodiment, coupler 509 comprises an elongate rod extending longitudinally from actuator 540 along axis 507. The distal portion of rod 508 is connected to stapes prosthesis 554. In the illustrative embodiment of
As noted above, various electrode assemblies may be used in embodiments of the present invention. For example, in embodiments of the present invention an electrode assembly may be implanted in basal region 116 (
As noted above, cochlea 140 is “tonotopically mapped.” That is, regions of cochlea 140 in basal region 116 are responsive to high frequency signals, while regions of cochlea 140 toward apex 146 are responsive to low frequency signals. As a result of this tonotopic arrangement, individuals may suffer sensorineural hearing loss only in certain frequency ranges. For example, certain individuals may loss the ability to perceive high frequency signals (ie. suffer sensorineual hearing loss in the basal regions of the cochlea), while retaining the ability to perceive low frequency signals. Such individuals maintain the ability to perceive middle to lower frequency sounds naturally, but have limited or no ability to perceive high frequency sounds. Short electrode assembly 646 of
In the embodiment of
As shown, short electrode assembly 646 includes an array of electrodes 648. Electrodes 648 are configured to apply electrical stimulation signals (not shown) to basal region 116 of cochlea 140. In certain embodiments, electrode assembly 646 comprises a perimodiolar electrode assembly configured to adopt a curved configuration during and or after implantation into the recipient's cochlea. In one such embodiment, distal portion 618 of electrode assembly 646 is pre-curved so as to be positioned in first turn 641. Electrode assembly 646 is held straight by, for example, a stiffening stylet (not shown) which is removed during implantation so that distal end 636 adopts the curved configuration. Other methods of implantation, as well as other electrode assemblies which adopt a curved configuration may be used in alternative embodiments of the present invention. In other embodiments, electrode assembly 646 comprises a non-perimodiolar electrode assembly which does not adopt a curved configuration.
Although the embodiments of
As previously noted, a bimodal hearing prosthesis in accordance with embodiments of the present invention may be configured to electrically and/or mechanically stimulate a recipient's cochlea. As such, at block 704, the bimodal hearing prosthesis selects which of these mode or modes of stimulation will be used to stimulate the recipient's cochlea. At block 706 the bimodal hearing prosthesis generates stimulation signals in accordance with the modes selected at block 704. At block 708, the recipient's inner ear is stimulated using the stimulation signals.
The invention described and claimed herein is not to be limited in scope by the specific preferred embodiments herein disclosed, since these embodiments are intended as illustrations, and not limitations, of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention.
Claims
1. A bimodal hearing prosthesis for rehabilitating the hearing of a recipient, comprising:
- a sound processing unit configured to process a received sound signal; and
- an implantable bimodal stimulation system, comprising: a mechanical stimulation arrangement configured to generate waves of fluid motion in the recipient's inner ear fluid based on the processed sound signal; an electrode assembly configured to deliver to the recipient's cochlea electrical stimulation signals generated based on the processed sound signal.
2. The prosthesis of claim 1, wherein the mechanical stimulation arrangement comprises:
- a stapes prosthesis having a first end configured to be positioned so as to abut an opening in one of the recipient's semicircular canals;
- an actuator configured to receive electrical signals representing the processed sound configured to vibrate in response to the electrical signals; and
- a coupler connecting the actuator to the stapes prosthesis such that vibration of the actuator results in the direct generation of waves of fluid motion in the semicircular canal.
3. The prosthesis of claim 1, wherein the mechanical stimulation arrangement comprises:
- an actuator configured to receive electrical signals representing the processed sound signal and configured to vibrate in response to the electrical signals;
- a stapes prosthesis having first and second ends, the first end having a surface configured to be positioned abutting the round window in the recipient's cochlea, and wherein the first end surface is substantially orthogonal to a longitudinal axis extending through the actuator; and
- an elongate rod connecting the actuator to the stapes prosthesis such that vibration of the actuator results in the direction generation of waves of fluid motion in the recipient's scala tympani.
4. The prosthesis of claim 2, wherein the coupler comprises:
- a first elongate component extending longitudinally from the actuator, and
- a second component attached to, and extending from the distal portion of the first component at an angle.
5. The prosthesis of claim 2, wherein the first elongate component comprises:
- an elongate rod having an adjustable length.
6. The prosthesis of claim 4, wherein the second component is attached to the first component by a pivot joint configured to permit adjustment of the angle at which the second component extends from the first component.
7. The prosthesis of claim 1, wherein the mechanical stimulation arrangement comprises an actuator configured to vibrate the recipient's skull.
8-14. (canceled)
15. The prosthesis of claim 1, further comprising:
- a preprocessor configured to evaluate the processed sound signal and to select which one or more of the mechanical stimulation arrangement and the electrode assembly is to be used to stimulate the recipient's cochlea based on the processed sound signal.
16. The prosthesis of claim 15, wherein the preprocessor is configured to perform a frequency analysis of the received sound signal to select which one or more of the mechanical stimulation arrangement and the electrode assembly is to be used to stimulate the recipient's cochlea
17. A method for rehabilitating the hearing of a recipient with a bimodal hearing prosthesis the prosthesis comprising an implantable electrode assembly configured to electrically stimulate a recipient and an implantable mechanical stimulation arrangement configured to mechanically stimulate the recipient's inner ear by generating waves of fluid motion in the recipient's inner ear fluid, the method comprising:
- receiving an acoustic sound signal;
- processing the acoustic sound signal;
- generating one or more of electrical stimulation signals and mechanical stimulation signals, based on the processed acoustic sound signal; and
- stimulating the recipient's inner ear based on the generated stimulation signals.
18. The method of claim 17, wherein generating one or more of electrical stimulation signals and mechanical stimulation signals, comprises:
- generating electrical stimulation signals, and
- simultaneously generating mechanical stimulation signals.
19. The method of claim 17, further comprising:
- directly generating waves of fluid motion in one of the recipient's semicircular canals.
20. The method of 17, further comprising:
- directly generating waves of fluid motion in the recipient's scala tympani.
21. The method of claim 19, wherein the mechanical stimulation arrangement comprises a stapes prosthesis having a first end configured to be positioned abutting an opening in the semicircular canal, an actuator and a coupler connecting the actuator to the stapes prosthesis, wherein generating the fluid motion comprises:
- receiving at the actuator electrical signals representing the processed sound signals;
- generating vibration with the actuator based on the electrical signals; and
- delivering the vibration to the fluid in the semicircular canal with the stapes prosthesis.
22. The method of claim 21, wherein the coupler comprises a first elongate component extending from the actuator, and a second component extending from the distal portion of the first component at an angle, wherein delivering the vibration to the fluid in the semicircular canal with the stapes prosthesis comprises:
- actuating the first component to exert a force on the fluid in the semicircular canal.
23. The method of 17, further comprising:
- delivering the mechanical stimulation signals to an actuator configured to generate vibration of the recipient's skull.
24. The method of claim 20, wherein the mechanical stimulation arrangement comprises a stapes prosthesis having a first end configured to be positioned abutting the round window in a recipient's cochlea, an actuator, and an elongate rod connecting the actuator to the stapes prosthesis, wherein generating the fluid motion further comprises:
- receiving at the actuator electrical signals representing the processed sound signals;
- generating vibration with the actuator based on the electrical signals; and
- delivering with the stapes prosthesis the vibration to round window.
25. (canceled)
26. The method of claim 17, further comprising:
- performing a frequency analysis of the received sound signal.
27-32. (canceled)
33. A bimodal hearing prosthesis for rehabilitating the hearing of a recipient, comprising:
- means for receiving an acoustic sound signal;
- means for processing the acoustic sound signal;
- means for generating one or more of electrical stimulation signals and mechanical stimulation signals, based on the processed acoustic sound signal; and
- means for stimulating the recipient's inner ear based on the generated stimulation signals.
34. The prosthesis of claim 33, wherein generating one or more of electrical stimulation signals and mechanical stimulation signals, comprises:
- means for generating electrical stimulation signals, and
- means for simultaneously generating mechanical stimulation signals.
35. The prosthesis of claim 33, further comprising:
- means for directly generating fluid motion in one of the recipient's semicircular canals.
36. The prosthesis of claim 33, further comprising:
- means for directly generating fluid motion in the recipient's scala tympani.
37. The prosthesis of claim 33, further comprising:
- means for delivering the mechanical stimulation signals to an actuator configured to generate vibration of the recipient's skull.
38. The prosthesis of claim 33, further comprising:
- means for performing a frequency analysis of the received sound signal.
Type: Application
Filed: Mar 31, 2009
Publication Date: Feb 3, 2011
Inventor: John Parker (New South Wales)
Application Number: 12/935,650
International Classification: A61F 11/04 (20060101); A61N 1/36 (20060101);