Abstract: An electrode array has an elongate flexible carrier that, when viewed in cross-section, is much more flexible in a first direction than in a second direction orthogonal thereto. The elongate flexible carrier is formed with a bias force that causes the array to flex in the first direction so as to assume the general spiral or circular shape of the scala tympani duct within the cochlea. The less-flexible direction is the direction that makes it difficult for the array to twist as it is inserted within the scala tympani duct. The bias force is sufficiently strong to cause the array to assume its preformed spiral shape even after being straightened during initial insertion into the cochlea. Electrode contacts, embedded into the carrier so as to be exposed along an inner or concave surface of the spiral, thus wrap snugly around the modiolus, thereby positioning the electrode contacts against the modiolar wall in an optimum position for stimulation.

Abstract: An implantable electrode array, adapted for insertion into either a left or right cochlea, assumes a spiral shape so as to hug the modiolar wall of the cochlea after insertion into the cochlea. All of the electrode contacts are spaced apart along one edge or side of the array, termed the "medial side", which medial side resides on the inside of the spiral. The electrode contacts are thus positioned in close proximity to the modiolar wall, closest to the ganglion cells that are to be stimulated by the electrode array. A positioning stylet made from a suitable memory wire is inserted into a longitudinal channel of the array. The stylet is made from memory wire and has properties selected to return to a desired memory spiral shape at or near body temperature (e.g., approximately 37.degree. C. or 98.6.degree. F.). The positioning stylet is cooled and bent as needed to assume a relatively straight, or non-spiral shape.

Abstract: An electrode array (10, 10') for stimulation of the cochlea includes an elongated tapered carrier (15) on which a multiplicity of separately controlled electrode contacts (20) are carried. A set of flexible fins (100, 110, 120) or bumps (120') or other dielectric members extend from the carrier in particular axes so as to cause the outside dimension of the array plus the dielectric members to readily fit within the cavity wherein the array is to be inserted. The dielectric members are made from compliant, dielectric material. When formed as fins, the dielectric members can be folded against the body of the carrier as it is inserted into the cochlea so that they readily slide past obstructions and accommodate variations in the cross-sectional dimensions of the cavity, e.g., the scala tympani (5) with only modest insertion forces.

Abstract: A tapered, flexible positioner, typically molded in a curved or hooked shape from a silicone polymer, is adapted to be inserted into the scala tympani duct of a human cochlea so as to position or force an electrode array, also inserted into the scala tympani duct, against the modiolar wall of the cochlea. The positioner may be inserted into the scala tympani duct before, or preferably after, insertion of the electrode array. The flexible positioner thus fills space within the scala tympani duct so as to force the electrode array, also inserted into the scala tympani duct, against the modiolar wall of the cochlea, where the electrode contacts of the electrode array may be more effective. In a preferred embodiment, a channeling groove is formed along one side of the positioner for receiving the electrode array.

Abstract: A dual prong hearing prosthesis for surgical implantation into both the scala tympani and the scala vestibuli of the inner ear of deaf persons is presented. The prosthesis consists of two prongs each with a plurality of closely spaced electrodes at the proximal end, said electrodes configured to stimulate the auditory nerves of the inner ear at a plurality of sites. One prong carries circumferentially-configured electrodes while the electrodes of the other prong are longitudinally-configured in relation to the length of the prong. Conductor lines from each electrode on both prongs terminate at the distal end in a contact pad arrangement thereby enabling convenient electrical connection between the implant and speech processing electronics. Means are disclosed to minimize kinking of the prongs during implantation, and to enable the electrodes to be in close proximity to the modiolus and basilar membrane thereby allowing for a high degree of versatility in selecting discrete stimulation sites.

Abstract: An electrode array has a flexible carrier that, when viewed in cross-section, is much more flexible in a first direction than in a second direction orthogonal thereto. The flexible direction is the direction that allows the array to readily flex so as to assume the general spiral or circular shape of the scala tympani duct within the cochlea. The less-flexible direction is the direction that makes it difficult for the array to twist as it is inserted within the scala tympani duct. By placing the electrode contacts of the array on or near that surface of the array which becomes the inner surface of the spiral shape once implantation has occurred, the electrode array may be inserted within the cochlea using minimal force, yet twisting of the array becomes unlikely during insertion or thereafter. Four separate embodiments of the electrode array are described.

Abstract: A holder of a biocompatible material for implantation in bone tissue for controlled receipt and positional fixation of equipment for electrical transfer of information. A cylindrical mounting part is for lying outside of the bone tissue and includes a mounting end and a smooth outer surface. A conical insertion part is for insertion into the bone tissue. The insertion part is narrower than the mounting part and includes an insertion end opposite the mounting end and tapers toward the insertion end at an angle of 0.degree. to 10.degree.. A conical intermediate part is between the mounting part and the insertion part. A plurality of retention elements are at least on the insertion part for providing good initial anchoring and stability to the holder and for permitting the holder to be mounted in a preprepared hole in the bone tissue without screwing the holder. A channel extends through the holder for receiving the equipment and connections to the equipment and including an exit opening in the insertion part.

Abstract: An electrode system includes (1) an electrode array, made in a straight or curved shape, but made on a flexible carrier so that it can easily bend within a curved body cavity, such as the cochlea; and (2) a flexible positioner, typically molded in a curved shape from a silicone polymer so as to make it easy to slide into the body cavity. Some embodiments may further include an electrode guiding insert. Yet other embodiments include only a flexible positioner adapted to fill space within a human cochlea so as to force an electrode array against a modiolar wall of the cochlea. Insertion of the electrode array is performed using one of two methods.

Abstract: Implantable device, such as a femoral head prosthesis, with a body (12) of biocompatible material shaped to suit its medical function, which forms an internal cavity (16) and has open apertures (18) that lead from the cavity (16) to the outside. The cavity (16) serves to receive spongiosa or other biological material into which the tissue that surrounds the implanted device is intended to grow through the apertures (18). The device is provided with at least two electrodes (30, 32), at least one of which is located in the cavity (16) spaced apart from the inside of the body (12) that forms the cavity (16). The electrodes are provided with an arrangement for supplying a low-frequency alternating voltage, so that by means of the supplied voltage a low-frequency electrical alternating field and a low-frequency alternating current, whereby the tissue growth is promoted, are created inside the cavity (16).

Abstract: An implantable cochlear electrode array includes an electrode carrier, a groove within the electrode carrier, and a flexible element located in the groove. After the electrode array is implanted, the flexible element may be held in place while the electrode carrier may be partially withdrawn so that the electrode carrier pulls away from the flexible element which emerges from the groove through the surface of the electrode carrier, except where the electrode carrier and the flexible element are attached, so that the electrode carrier wraps around an inner scala tympani wall. A portion of the apical end of the electrode carrier may extend beyond the ends of the groove and the flexible element so that the apical end of the electrode carrier does not wrap around the inner scala tympani wall when the electrode carrier is partially withdrawn after insertion in the cochlea.

Abstract: An implant stimulator device uses tantalum and tantalum pentoxide as a system for the conveyance of electrical stimulation pulses from stimulus-forming circuitry contained within an hermetic enclosure to the saline fluids of body tissue to be stimulated. Internal coupling capacitors are not used, yet the danger of having DC current flow to the saline fluids is eliminated. A preferred embodiment provides a multiplicity of electrode contacts made from sintered, anodized tantalum, connected via tantalum wire leads to tantalum feedthroughs into the hermetically sealed package containing the stimulus pulse-forming electronic circuitry. One or more counter electrode contacts (for monopolar or bipolar configurations, respectively) made of activated iridium, non-activated iridium, iridium in combination with a noble or non-noble metal, platinum, gold, or other metal which forms a low impedance contact with body fluids, is/are connected via platinum or other conductive metal leads to return feedthroughs.

Abstract: Apparatus for electric stimulation and diagnostics of auditory nerves of a human being, e.g. for determination of sensation level (SL), most conformable level (MCL) and uncomfortable level (UCL) audibility curves, includes a stimulator detachably secured to a human being for sending a signal into a human ear, and an electrode placed within the human ear and electrically connected to the stimulator by an electric conductor for conducting the signals from the stimulator into the ear. A control unit is operatively connected to the stimulator for instructing the stimulator as to characteristics of the generated signals being transmitted to the ear.

Abstract: A hearing prosthesis for implantation into a subject's ossified cochlea includes a plurality of electrode carriers associated with a single receiver/stimulator, and a plurality of contact member pairs arranged at a predetermined spacing along a fraction of the length of each electrode carrier. Each contact member pair is superficially placed on the carrier and comprises a first contact member diametrically opposed to a second contact member.

Abstract: A hearing prosthesis is provided for implantation into a subject that includes a flexible electrode carrier for insertion along the length of the cochlea, the electrode carrier bearing along its length, a number of contact members that are superficially placed in pairs, each member of each pairs being diametrically opposite the other. A method of manufacture of the prosthesis is further provided.

Abstract: An implant device uses tantalum and tantalum pentoxide as a complete system for the conveyance of electrical stimulation pulses from stimulus-forming circuitry contained within an hermetic enclosure to the saline fluids of the cochlea (or other tissue to be stimulated). Internal coupling capacitors are not used, yet the danger of having DC current flow to the saline fluids is eliminated. A preferred embodiment is a cochlear prosthesis comprised of a multiplicity of electrode contacts made from sintered, anodized tantalum, connected via tantalum wire leads to tantalum feedthroughs into the hermetically sealed package containing the stimulus pulse-forming electronic circuitry. One or more counterelectrode contacts (for monopolar or bipolar configurations, respectively) consist of activated iridium, connected via platinum or other noble metal leads to noble metal feedthroughs.

Abstract: A tubular prosthesis formed by an assembly of electrode segments enclosing n elongated inner chamber, is inserted into the inner ear of a patient for piezoelectric generation of electrical impulses and localized injection thereof in response to externally generated sound waves. Such electrical impulses are applied from the prosthesis to nerve endings adjacent to cochlea contact locations on the electrode segments so as to improve hearing adversely affected by biological damage to the inner ear.

Abstract: A multi-electrode cochlear implant is taught in which approximately twenty or more insulated metal wires are wound around a flexible tube. These wires are held in place with a further layer of dielectric insulating material. The insulation is selectively removed with a laser beam to form electrodes. Two or more layers or valences of wires can be used, with the inner layer of wires terminating distal to the outer layers to provide a stepwise approximation of the tapering of the scala tympani. A shape memory material core may be introduced into the tube, so that the implant will retain an effective shape after implantation. In a preferred embodiment, electrical conductors are connected to the shape memory material to permit the select warming of the shape memory material by the passing of an electric current through it. In an alternative preferred embodiment, the shape memory material is warmed by adjacent heating elements.

Abstract: A method for evaluating the electromotility of hair cells within the cochlea of a mammalian ear by providing an electrode in proximate relation with the round window and applying electricity therethrough in order to electrically excite hair cells within the cochlea to produce electrically-evoked otoacoustic emissions therefrom. The electrically-evoked otoacoustic emissions further excite the internal structure of the cochlea which produces vibrations at the oval window that act through the bones of the middle ear to drive the tympanic membrane, producing corresponding acoustic sounds in the ear canal. The resulting acoustic sounds in the ear canal are subsequently detected with a microphone where they are later measured and characterized via readily available signal processing techniques.

Abstract: An implant such as a cochlear assembly, or other similar device, includes an elongated therapeutic member arranged and constructed to perform a therapeutic function. The therapeutic member has at least two configurations: an insertion and a deployed configuration. The first configuration is selected to ease the insertion of the member into a body cavity. A stiffening member is used to urge said therapeutic member toward said first configuration. The stiffening member is made of a bioresorbable material so that after insertion, the stiffening member dissolves and allows the therapeutic member to assume the second configuration.

Abstract: An electrode array for implantation in volume-conductive media, such as living tissue, includes at least two closely spaced metal contacts, with arbitrary shapes, having large enough surface areas to preclude one or both from acting as a "point source." Through proper control of the shape of the contacts, and the impedance ratio between the metal-electrolyte interface and the intervening volume-conductive media, achieved through use of appropriate materials for the metal contacts in combination with electronic adjustment of the voltage pulse applied between the contacts, desirable "edge-effect" fields are created that better control and manage the distribution of the resulting stimulation current flowing between the contacts. Such control of the stimulation current distribution allows a given electrode array to be electronically tuned to better stimulate specific neurons found within the tissue.

Abstract: An implantable cochlear electrode assembly includes a flexible rod-like electrode carrier and a flexible rod-like positioning member which are initially parallel to and closely alongside each other and, when the assembly is inserted endwise into the cochlea, adopt the spiral curvature of the cochlea. The electrode carrier and the positioning member are connected to each other at their respective leading end regions by a latchless rod-and-socket joint and at their respective trailing end regions by a ring-shaped member having a generally D-shaped cross-sectional configuration, with the flat wall of the "D" defining the circumferential boundary surface of the passageway in the ring member through which the electrode carrier and the positioning member jointly pass with a close fit.

Abstract: A multi-electrode cochlear implant is taught in which approximately twenty or more insulated metal wires are wound around a flexible tube. These wires are held in place with a further layer of dielectric insulating material. The insulation is selectively removed with a laser beam to form electrodes. Two or more layers or valences of wires can be used, with the inner layer of wires terminating distal to the outer layers to provide a stepwise approximation of the tapering of the scala tympani. A core of shape memory material may be introduced into the tube, so that the implant will retain an effective shape after implantation.

Abstract: An improved sound processor, with particular application to stimulation of implanted electrode arrays, such as cochlear implants. The processor channelizes received sound signals into at least ten analysis channels to produce amplitude signals for each channel. A predefined number of channels with the largest amplitude are used to modulate stimuli for the implanted array. The predefined number is at least four, and less than or equal to half the number of analysis channels.

Abstract: An electrode array (12) for cochlear (30) implant is formed by two layers, wherein the first layer (10, 20) is formed from a bio-compatible material and contains electrode contacts and connecting leads and the second layer (11, 21) is formed from a bio-compatible material having a property of a controlled rate of expansion when exposed to the water contained in body fluids. This material expands in use and curves the implanted array and enables more effective stimulation.

Abstract: An implantable cochlear electrode assembly includes an initially straight flexible rod-like electrode carrier and an initially straight flexible rod-like positioning member which extend in substantially parallel relation to and closely alongside each other. The assembly is inserted endwise into the scala tympani of the cochlea so as to adopt the spiral curvature of the cochlea, with the positioning member being disposed at that side region of the electrode carrier which faces the outer wall of the cochlea and is opposite to the side region of the electrode carrier at which the contact faces of the array of electrodes are exposed.

Abstract: A cochlear electrode comprising a spirally curved distal tip portion carrying electrical conductors for stimulating the cochlea, a lead offset from the distal tip portion and a bridge therebetween and extending from the distal tip adjacent the proximal terminus thereof. The bridge defines a slide for guiding the distal tip portion into and out of an insertion tool during implantation of the electrode while the proximal terminus defines a push point for a push rod included in the insertion tool for sliding the distal tip out of the tool and into the cochlea.

Abstract: Charging system for implantable hearing aids and tinnitus maskers with a repeatedly rechargeable direct voltage source. The charging system comprises an implantable receiving resonant circuit as the electrical energy source for the direct voltage source to be charged and a transmitting resonant circuit located outside the body that can be inductively coupled with the receiving resonant circuit for power transmission from outside the body to inside the body. Embodiments are provided for transcutaneous and for percutaneous power transmission between the implantable receiving resonant circuit and the external transmitting resonant circuit.

Abstract: An improved pulsatile system for a cochlear prosthesis is disclosed. The system employs a multi-spectral peak coding strategy to extract a number, for example five, of spectral peaks from an incoming acoustic signal received by a microphone. It encodes this information into sequential pulses that are sent to selected electrodes of a cochlear implant. The first formant (F1) spectral peak (280-1000 Hz) and the second formant (F2) spectral peak (800-4000 Hz) are encoded and presented to apical and basal electrodes, respectively. F1 and F2 electrode selection follows the tonotopic organization of the cochlea. High-frequency spectral information is sent to more basal electrodes and low-frequency spectral information is sent to more apical electrodes. Spectral energy in the regions of 2000-2800 Hz, 2800-4000 Hz, and above 4000 Hz is encoded and presented to three fixed electrodes.