HOUSING HAVING EAR CANAL MOUNTED TRANSDUCER SPEAKER AND MICROPHONE

INVENTOR: ALFRED E. MANN, DAVID A. KRUBSACK, BYRON L. MORAN, ANDRE L. GOLDSTEIN

RELATED APPLICATIONS

[0001] This PCT International application claims priority based on U.S. provisional application 61/188,434 filed on 31 July 2008.

FIELD OF THE INVENTION

[0002] This invention relates generally to hearing aid systems and more particularly to a system including a housing configured for subcutaneous implantation in a patient's retro-auricular space to locate both a sound producing transducer (e.g., speaker) and a sound responsive transducer (e.g., microphone) in, or adjacent to, a patient's ear canal.

BACKGROUND OF THE INVENTION

[0003] U.S. Patent 7,127,078 issued October 24, 2006, which is incorporated herein by reference, describes a hearing aid system including a housing configured for implantation in a patient's retro-auricular space extending subcutaneously to the patient's outer ear canal. The housing includes an antenna, electronic circuitry, and a sound producing transducer. The transducer functions to convert electrical signals into sound energy which is projected into the patient's ear canal. Patents 6,786,860; 6,879,695; and 7,224,815 describe related innovations. [0004] U.S. Patent application 10/821,383 filed on April 9, 2004, which is incorporated herein by reference, describes an implantable percutaneous device, and method of implantation, especially configured to promote soft tissue ingrowth for creating an infection resistant barrier and for anchoring the implanted device in place.

[0005] PCT application PCT/US2004/041596 filed on 10 December

2004, which is incorporated herein by reference, describes a surgical instrument set and procedure for implanting a hearing aid housing so as to locate a sound producing transducer proximate to a patient's outer ear canal. In a preferred embodiment, the transducer is mounted in a housing stud which projects through a percutaneous hole opening into the ear canal. [0006] PCT application PCT/US2006/006588 filed on 23 February

2006, which is incorporated herein by reference, describes a fully implantable hearing aid system comprised of an implantable sound generator module and an implantable sound receiver module connected by an implantable electric cable. In an exemplary embodiment, the sound generator module is subcutaneously implanted in soft tissue through an incision behind the patient's pinna to place a sound producing transducer, e.g., speaker, in or adjacent to the patient's outer ear canal. The sound receiver module is implanted in a location proximate to the patient's pinna to place a sound responsive transducer, e.g., microphone, so that it is acoustically isolated from the sound producing transducer.

SUMMARY OF THE INVENTION

[0007] The present invention is directed to a hearing aid system comprised of a housing configured for subcutaneous implantation in a patient's retro-auricular space so that the distal portion of the housing extends into, or immediately adjacent to, a patients ear canal. The distal portion is configured to extend percutaneously to the patient's ear canal to locate both a sound producing transducer, e.g., speaker, and a sound responsive transducer, e.g., microphone, in, or immediately adjacent to, the patient's ear canal. In order to minimize the effects of acoustic feedback, an electronic feedback suppression subsystem is incorporated between the sound producing transducer and the sound responsive transducer. In a preferred embodiment, the feedback suppression subsystem comprises an electronic signal processor executing an adaptive acoustic cancellation algorithm. [0008] An implant housing in accordance with the invention preferably carries a layer of porous material proximate to its distal portion to promote soft tissue ingrowth around the percutaneous penetration site for creating an infection resistant barrier and for anchoring the housing. [0009] In a first embodiment of the invention, both the sound producing transducer and the sound responsive transducer are mounted at the distal end of the implant housing for placement in, or immediately adjacent to, the patient's ear canal. In an alternative embodiment, one or both of the transducers can be mounted in a separate transducer module case configured for exchangeable attachment to the implant housing via the patient's open ear canal, in a manner which allows the transducer module to be readily replaced for service and/or enhancement.

[0010] More particularly, the housing can define a cavity accessible via the patient's ear canal configured to mate with a transducer module adapted to be inserted into and withdrawn from the cavity. The transducer module can carry one or more terminals configured to automatically electrically contact mating terminals on the housing when the transducer module is properly seated in the cavity. Alternatively, the transducer module can carry an electric coil configured to inductively couple to an electric coil in the housing when the transducer module is properly seated in the cavity.

BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1 is a sectional view schematically showing a subcutaneously implanted housing having a distal portion extending percutaneously into a patient's outer ear canal;

[0012] Figure 2 is a side sectional view showing the housing distal portion extending percutaneously into a patient's outer ear canal; [0013] Figure 3 is a cross sectional view taken substantially along the plane 3-3 of Figure 2 showing a sound producing transducer and a sound responsive transducer carried by the housing distal portion; [0014] Figure 4 is a block diagram schematically representing the interconnection of the transducers and electronic components within the implant housing;

[0015] Figure 5 is an exploded isometric illustration of an alternative embodiment of the invention showing an implantable housing and an exchangeable transducer module configured for axial mounting on the housing via the patient's ear canal;

[0016] Figure 6 is similar to Figure 5 but shows the transducer module mounted on the housing;

[0017] Figure 7 is a longitudinal sectional view taken through the housing and transducer module of Figure 6; [0018] Figure 8 is a sectional view similar to Figure 7 but showing the use of coils for inductively coupling the transducer module and housing electronics;

[0019] Figure 9 is an exploded isometric view of an alternative embodiment of the invention showing the transducer module displaced from the housing and positioned for lateral mounting on the housing via the patient's ear canal;

[0020] Figure 10 is similar to Figure 9 but shows the transducer module mounted on the housing; and

[0021] Figure 11 is an exploded isometric view showing exemplary housing and module connectors of the embodiment of Figures 9 and 10.

DETAILED DESCRIPTION

[0022] Attention is initially directed to Figures 1 and 2 which illustrate a hearing aid system housing 10 implanted in a patient's subcutaneous tissue 12 of a patient's retro-auricular space. The housing 10 comprises a body portion 13 and a distal portion, or stud, 14 which projects distally from the body portion to percutaneously penetrate skin tissue 16 surrounding the patient's outer ear canal 18. A housing generally similar to that depicted in Figure 1 is described in aforementioned U.S. patent application 10/821 ,383. The housing 10 includes a longitudinally extending body surface 21, a laterally oriented shoulder surface 22, and a longitudinally extending stud surface 23. A layer of porous material 24 is preferably affixed to the longitudinal body portion surface 21, the longitudinal stud surface 23, and the lateral shoulder surface 22. The porous material 24 acts to promote healthy tissue ingrowth to form a bacteria resistant barrier around the percutaneous penetration site 26 through skin tissue 16. As described in said Application 10/821 ,383, the porous layer 24 is preferably formed by a mesh of intersecting fibers of a suitable biocompatible material such as a metal, e.g., titanium, nitinol, silver, or stainless steel or a polymeric material, e.g., polyolefins, Teflon, nylon, Dacron, or silicone. The mesh is preferably formed by cross winding the fibers in multiple layers to define a porosity conducive to promoting soft tissue ingrowth, e.g., with pore sizes within a range of 50 to 200 microns and having a porosity of 60 to 95%. Also, it is generally desirable to apply a coating containing one or more antimicrobial and/or anti-inflammatory agents on the housing exterior surface and/or porous layer to promote tissue healing and/or resist infection and inflammation. Suitable agents are known in the literature and include, for example, antibiotics, silver compounds, and steroid based agents.

[0023] The aforementioned application PCT/US2004/041596 describes a preferred surgical instrument set and procedure for implanting the housing 10 with the stud 14 extending through the percutaneous penetration site, i.e., hole 26, in tissue 16 into the outer ear canal 18. The preferred housing described in said PCT/US2004/041596 houses a power supply and electronic circuitry for driving an electroacoustic transducer mounted in the stud for projecting sound energy directly into the patient's outer ear canal. Typically, the housing 10 will have a length between its proximal face 27 and distal face 28 of about 2.5 cm, a height of about 0.7 cm and a width of about 0.5 cm. [0024] The present invention is directed to an enhanced hearing aid system in which the distal portion, or stud, 14 of the implanted housing 10, as shown in Figure 3, carries at least one electrically driven sound producing ("SP") transducer 30, e.g., speaker, for directing sound or acoustic, energy into the ear canal and at least one sound responsive ("SR") transducer 32, e.g., microphone, for responding to incident acoustic energy for generating a representative electric signal for driving transducer 30. The transducers 30 and 32 are preferably mounted in the stud 14 substantially coplanar with the stud distal face 28. The transducers 30, 32 are preferably spaced in the direction of the ear canal 18 with the SR transducer 32 preferably positioned closer to the ear canal exterior opening and the SP transducer 30 positioned more deeply in the canal.

[0025] Figure 4 is a schematic block diagram representing the SR transducer 32 and the SP transducer 30 mounted near the distal face 28. The SR transducer 32 functions to produce an electric output signal, representative of the acoustic energy incident thereon, which is supplied to signal processing circuitry 36 for producing a signal suitable for driving the SP transducer 30. In order to minimize the adverse effect of acoustic feedback from the SP transducer 30 to the SR transducer 32, the signal processing circuitry 36 also functions to electronically cancel acoustic feedback. The feedback cancellation circuitry can be implemented in a variety of ways, e.g., see U.S. Patent 6,876,751, to effectively cancel the effect of the acoustic output produced by SP transducer 30 on the SR transducer 32. Most simply this can be done by enabling the signal processing circuitry 36 to execute a feedback cancellation algorithm, of the type described in aforementioned Patent 6,876,751.

[0026] Although not expressly shown, it is assumed that signal processing circuitry 36 incorporates suitable amplification and equalization stages which can be remotely, e.g., wirelessly, set by an audiologist and/or the user via control circuitry 37. The housing 10 preferably also contains a power supply 39, e.g., a rechargeable battery, for powering the various electrical elements shown in Figure 4.

[0027] Although Figure 3 depicts the transducers 30, 32 as mounted within the stud 14, alternatively the transducers can be mounted in an exchangeable transducer module configured for detachable coupling to the stud. Now, for example, consider Figures 5-7 which illustrate a further embodiment 100 of the invention comprised of an implant housing 102 and an exchangeable transducer module 104. Housing 102 is comprised of an implantable body portion 112 having a distal stud 106 for projecting percutaneously into the patient's ear canal 108. The transducer module 104 is configured for exchangeable mounting on the stud 106 to electrically and structurally connect the module 104 to the housing 102. [0028] The transducer module 104 is comprised of a sound responsive

(SR) transducer (e.g., microphone) device 120 and a sound producing (SP) transducer (e.g., speaker) device 122. The devices 120 and 122 are structurally connected, preferably by a stiff flexible conduit 124. The length and shape of the conduit 124 may be customized to optimize acoustic performance for a particular patient's ear canal geometry. The conduit 124 can pass wires or other conductors for electronically connecting transducer devices 120, 122. The transducer module 104 may contain miniature electronic circuitry to optimally interface with the SR and SP transducers and may also include signal processing / adaptive feedback cancellation and control circuitry.

[0029] The SR transducer device 120 is preferably comprised of a casing 126 containing a miniature SR transducer, e.g., a microphone, (not shown) oriented to react primarily to sound energy incident on its flat proximal face 127. The SP transducer device 122 is preferably comprised of a casing 128 containing an SP transducer, e.g., a miniature receiver/speaker (not shown) oriented to direct sound energy out from its distal face 130. [0030] More particularly, as seen in Figures 5-7, the stud 106 defines a recess 138 in which multiple male contacts or pins 136 are mounted. A connector 138 on the SR casing 126 defines a neck 139 having a periphery which is shaped to nest in recess 134. The neck 139 carries multiple female contacts, or sleeves 140, each configured to receive and contact one of the male contact pins 136. The implant housing 102 is preferably dimensioned so that when surgically implanted in the patient's retroauricular space, the distal end of stud 106 protrudes percutaneously a short longitudinal distance, e.g., 0 to 4mm into the patient's ear canal 18.

[0031] With housing 102 properly implanted so that its stud 106 protrudes into, or immediately adjacent to, the patient's ear canal, the transducer module 104 can be inserted into the ear canal for mounting on, and removal from, the stud by applying an appropriately directed longitudinal force, to the SR casing 126 in the direction of arrow 142. The housing recess 134 and module neck 138 are preferably dimensioned with sufficient longitudinal overlay, e.g., 6mm, so that when nested, the transducer module 104 is securely structurally mounted on the implant housing 102. Of course, when properly nested, the contact pins 134 of housing 102 will be electrically engaged with contact sleeves 140 of transducer module 104. [0032] Whereas, the embodiment of Figures 5-7 relies on contact pins and sleeves for electrically connecting transducer module 104 to housing 102, Figure 8 illustrates an alternative arrangement in which housing 102 carries a coil 144 and transducer module 104 carries a coil 146. When the transducer module 104 is properly seated on the housing, the coils 144 and 146 are effectively inductively coupled.

[0033] Attention is now directed to Figures 9-11 which illustrate a further preferred embodiment 160 of the invention. Whereas the transducer module 104 of Figures 5-7 is moved longitudinally to mount module connector 138 onto housing connector 134, the transducer module 162 of Figures 9-11 is moved laterally (arrow 164) to mount it to implant housing 166. [0034] More particularly, note that implant housing 166 includes a distal Iy projecting stud 168 having a laterally, or side opening, cavity 170 containing multiple electric contacts 172 (Figure 11). The cavity 170 and contacts 172 together form a housing connector 174 for mating with a transducer module connector 178 for structurally and electrically connecting the module 160 to the implant housing 166.

[0035] Note that transducer module 160 is comprised of a casing 180 having a proximal face 182 and a distal face 184. A sound responsive transducer (not shown) is preferably oriented in casing 180 to respond to sound energy primarily incident on proximal face 182 and a sound producing transducer (not shown) is preferably oriented in casing 180 to direct sound energy out through distal face 184. Further, the transducer module may contain miniature electronic circuitry to interface with the SR and SP transducers and for implementing signal processing / adaptive feedback cancellation and control.

[0036] Note that the transducer module casing 184 is undercut at 190 to define a laterally oriented surface 192 and a longitudinally oriented surface 194. Multiple electric contacts 196, e.g., spring contacts 198, project laterally from surface 194. These contacts 198 are configured to engage contacts 172 mounted in housing cavity 170 when module surface 192 is slid laterally across the distal lateral surface 202 of housing stud 168. Although not shown, it should be appreciated that the embodiment of Figures 9-11 could be modified to use inductively coupled coils instead of spring contacts. [0037] From the foregoing, it should now be understood that the present invention is directed to a hearing aid system in which an implanted housing is configured to place both a sound producing transducer and a sound responsive transducer in, or adjacent to a patient's outer ear canal with acoustic feedback cancellation circuitry provided to eliminate acoustic coupling. Although only a limited number of embodiments have been described herein, it is recognized that additional variations and modifications are likely to occur to those skilled in the art. For example only, it is recognized that the respective mating connectors on the transducer module and implant housing can take a variety of alternative forms. Additionally, it is recognized that alternative geometries can readily be employed to optimize inductive coupling of the coils (Figure 8). It is intended that all such variations and modifications which are consistent with the spirit and teachings of the invention fall within the scope of the appended claims.