Abstract: An implantable microphone system senses “sound” by sensing motion of middle ear components without having to physically touch or contact such elements. In one embodiment, acoustically induced vibrations in any of the moving components of the middle ear are detected using a pulsed echo Doppler ultrasound transducer, implanted in the middle ear. The implantable microphone system is ideally suited for use with a cochlea implant device.

Abstract: Improved implantable microstimulators are covered with a biocompatible polymeric coating in order to provide increased strength to the capsule and to capture fragments of the microstimulator should it become mechanically disrupted. Such coating also makes the microstimulator safer and easier to handle. The coating may include one or more diffusible chemical agents that are released in a controlled manner into the surrounding tissue. The chemical agents, such as trophic factors, antibiotics, hormones, neurotransmitters and other pharmaceutical substances, are selected to produce desired physiological effects, to aid, support or to supplement the effects of the electrical stimulation. Further, microstimulators in accordance with the invention provide systems that prevent and/or treat various disorders associated with prolonged inactivity, confinement or immobilization of one or more muscles. Such disorders include pressure ulcers, venous emboli, autonomic dysreflexia, sensorimotor spasticity and muscle atrophy.

Abstract: An external power transfer circuit (12) couples ac power having a fixed frequency into an implantable electrical circuit (14), e.g., an implantable tissue stimulator, while automatically maintaining optimum power transfer conditions. Optimum power transfer conditions exist when there is an impedance match between the external and implanted circuits. The external transfer circuit includes a directional coupler (42) and an impedance matching circuit (44). The directional coupler senses the forward power being transferred to the implant device, as well as the reverse power being reflected form the implant device (as a result of an impedance mismatch). The impedance matching circuit includes at least one variable element controlled by a control signal.

Abstract: A stapedius electrode attaches to or is embedded within the stapedius muscle (20) at a point near where the stapedius muscle is visible as it exits a bony channel (30) within the middle ear. In one embodiment, the electrode is made from a biocompatible metal wire formed into a flat blade (102) having a sharp tip (104) and serrations (103) along one edge. An insulated lead attaches electrically and mechanically to the blade. Such attachment may be made by welding and wrapping the insulated lead at one end of the wire around the body of the electrode and protecting such weld and securing such wrappings with a coating or blob of epoxy. During implantation of the electrode, the electrode blade is inserted through a small slot made in the muscle tissue. Alternatively, the electrode may be inserted alongside the muscle tissue through an opening in the bony wall as it passes through the bony channel, with a tip of the electrode protruding from the bony channel.

Abstract: A paddle-type electrode or electrode array is implantable like a percutaneously inserted lead, i.e., without requiring major surgery, but once inserted, expands to provide a platform for many electrode configurations. The electrode array is provided on a flexible, foldable, subcarrier or substrate. Such subcarrier or substrate is folded, or compressed. during implantation, thereby facilitating its insertion using simple, well-known percutaneous implantation techniques. Once implanted, such subcarrier or substrate expands, thereby placing the electrodes in a desired spaced-apart positional relationship, and thus achieving a desired electrode array configuration. A memory element is used within the subcarrier or substrate which causes the electrode array to expand or unfold to a desired unfolded or expanded state after it has been implanted while in a folded up or compressed state.

Abstract: A multi-output connector for use with an implantable neurostimulator, or similar implantable stimulator, is described. The connector includes three main components: an output bracket (10), a receiver (20), and a clamp (30). The output bracket forms part of the stimulator and is typically made from a hard polymer, such as epoxy resin. It has a T-shaped cross section, and has an array of metal contacts placed on both sides of the base of the “T”. The receiver is made from a soft polymer, such as silicone rubber, and has a T-slot formed therein adapted to match the T-shaped cross-section of the output bracket. Contact pins are formed in the side walls of the receiver so as to make electrical contact with the metal contacts of the output bracket when the receiver is placed over the bracket. The clamp is made from metal in the form of a U-shape and fits over the top of the receiver 20 to apply compression to both side of the receiver.

Abstract: Monitoring/measurement circuitry within an implantable stimulator, e.g., an implantable cochlear stimulator (ICS), includes a first analog multiplexer (MUX) connected to a gain controlled, low noise, differential amplifier. The output of the differential amplifier is coupled to a second analog MUX along with other analog signals, e.g., operating or bias voltages used within the implantable stimulator. The signal appearing at the output of the second analog MUX is preliminary processed as required, e.g., to adjust the amplitude (attenuate) and/or filter out high frequency components. Once processed, the signal is then digitized in an analog-to-digital (A/D) converter. The digitized signal is then stored in memory as measured data, and eventually transmitted to a remote (non-implanted) processor for further processing, analysis, examination and/or feedback.

Abstract: An implantable space-filling electrode system, adapted for insertion into a cochlea, includes an elongate electrode array and a positioner. The electrode array has a multiplicity of electrode contacts carried on a flexible elongate carrier, which carrier is adapted for insertion into one of the spiraling ducts, e.g., the scala tympani, of the cochlea. The positioner is an elongate, flexible member, having a longitudinal channel that passes therethrough. The positioner is adapted to reside in and fill the space in the cochlear channel behind the electrode array so as to position and maintain the electrode array against a modiolar wall of the cochlea. A distal tip of the positioner is detachably joined to the electrode array at one point near the distal tip of the electrode array. To insert the electrode system into the cochlea, a stylet wire is inserted into the channel of the positioner, and the positioner is then gently guided and pushed into the cochlea by extending the stylet wire.

Abstract: Improved implantable microstimulators are covered with a biocompatible polymeric coating in order to provide increased strength to the capsule and to capture fragments of the microstimulator should it become mechanically disrupted. Such coating also makes the microstimulator safer and easier to handle. The coating may include one or more diffusible chemical agents that are released in a controlled manner into the surrounding tissue. The chemical agents, such as trophic factors, antibiotics, hormones, neurotransmitters and other pharmaceutical substances, are selected to produce desired physiological effects, to aid, support or to supplement the effects of the electrical stimulation. Further, microstimulators in accordance with the invention provide systems that prevent and/or treat various disorders associated with prolonged inactivity, confinement or immobilization of one or more muscles. Such disorders include pressure ulcers, venous emboli, autonomic dysreflexia, sensorimotor spasticity and muscle atrophy.

Abstract: A programmable output current source for use within an implantable tissue or nerve stimulator, e.g., an implantable cochlear stimulator or spinal cord stimulator, includes parallel-connected P-FET current source sets connected between a positive voltage rail and an electrode node, and parallel-connected N-FET current source sets connected between the electrode node and a negative voltage rail. The N-FET current source sets include n N-FET current sources, where n is an integer 0, 1, 2, 3, 4, . . . , and wherein each N-FET current source, when enabled, respectively sinks a current 2nI from the electrode node to the negative rail, where I is a selectable fixed current. Similarly, the P-FET current source sets include n P-FET current sources, where n=0, 1, 2, 3, . . . n, and wherein each P-FET current source, when enabled, respectively sources a current 2nI from the positive voltage rail to the electrode node.

Abstract: An implantable medical device, such as an implantable cochlear stimulator (ICS) system, utilizes laminated, sectionalized or particle-ized permanent magnets and/or keepers in both the implant portion and external (non-implanted) portion so as to reduce the electrical energy absorbed by both the implant device and the external device when in use. In one embodiment, the implant device employs a sectionalized, laminated or particle-based “keeper”, while the external device employs a sectionalized, laminated or particle-ized magnet, making the implant device immune to being damaged by MRI (magnetic resonance imaging).

Abstract: Improved implantable microstimulators are covered with a biocompatible polymeric coating in order to provide increased strength to the capsule and to capture fragments of the microstimulator should it become mechanically disrupted. Such coating also makes the microstimulator safer and easier to handle. The coating may include one or more diffusible chemical agents that are released in a controlled manner into the surrounding tissue. The chemical agents, such as trophic factors, antibiotics, hormones, neurotransmitters and other pharmaceutical substances, are selected to produce desired physiological effects, to aid, support or to supplement the effects of the electrical stimulation. Further, microstimulators in accordance with the invention provide systems that prevent and/or treat various disorders associated with prolonged inactivity, confinement or immobilization of one or more muscles. Such disorders include pressure ulcers, venous emboli, autonomic dysreflexia, sensorimotor spasticity and muscle atrophy.

Abstract: A method of positioning an electrode array within a human cochlea includes making a flexible positioner as a curved or hooked shape from a silicone polymer. The positioner is adapted to be inserted into the scala tympani duct of a human cochlea. The positioner may be inserted into the scala tympani duct before, concurrent with, or after, insertion of the electrode array. The flexible positioner 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 one embodiment, a channeling groove is formed along one side of the positioner for receiving the electrode array. Also, in one embodiment, a silastic tube forms a molded-in tube within the molded positioner, and provides a lumen, sealed or closed at its distal end, into which a stylet wire may be inserted during the insertion process.

Abstract: A self-adjusting implantable cochlear implant system (46) includes an implant portion (50) and an external portion (53). The system provides a device and a way to objectively determine selected psychophysical parameters, such as stimulation threshold, comfort level and loudness resolution, used by the implant portion, which includes an implantable cochlear stimulator (ICS), as it carries out its stimulation function. The input to the system is an electrical stimulation. The outputs of the system include a middle ear reflex (MER) and evoked potentials, such as a compound action potential (CAP) along the auditory/cerebral pathways, both of which are sensed using objective measurement techniques and tools. In accordance with one embodiment, the adjustment process uses the MER for determining a coarse threshold value, and then (using such coarse threshold value as a starting point) uses evoked potentials to determine a more precise o fine threshold value, thereby zeroing in on a desired threshold.

Abstract: An insertion tool is used to insert an electrode array or positioner into a human cochlea. The insertion tool includes a main body portion (151), a pushing tube (152) slidably engaged within the main body portion so that the pushing tube may assume a retracted or extended position, and a stylet (154) slidably inserted into the pushing tube and having a retracted position and an extended position. In use, a positioner (or other flexible member), having a longitudinal hole or channel passing therethrough, is threaded onto the distal end of the stylet at a time when the stylet is in its extended position and the pushing tube is in its retracted position. Then, the pushing tube is pushed or slid to its extended position while maintaining the stylet in its extended position, thereby pushing the positioner (or other flexible member) off of the stylet and into the cochlea.

Abstract: 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. The electrode array having a multiplicity of electrode contacts along a front side of the electrode array and a plurality of flexible ribs located on an opposite rear side. Insertion of the electrode array is performed by inserting the electrode array into the scala tympani (one of the channels of the cochlea) to a desired depth, which desired depth typically involves a rotation of about 360 degrees and causes the flexible ribs to make contact against the outer or lateral wall of the scala tympani, positioning the electrode contacts adjacent the inner wall of the scala tympani.

Abstract: A method of making an implantable electrode array, adapted for insertion into a cochlea, provides stability relative to the electrode contact direction. In-line electrodes are spaced-apart along one side of a flexible carrier. The structure of the electrode array facilitates bending of the array with the electrode contacts on the inside of the bend, yet deters flexing or twisting of the array in other directions. The electrode contacts preferably are each made from two strips of metal, arranged in a "T" shape (top view). During assembly, all of the "T" strips are held in position on an iron sheet. Two wire bundles are formed that pass along each side of each "T". The leg of each "T" is folded over to pinch at least one of the wires from one of the wire bundles therebetween. This pinched wire is then resistance welded to the strip. The sides of the "T" are then folded up and touch or nearly touch to form a ".DELTA." shape (side view). The wire bundles going to more distal electrodes pass through the ".DELTA.

Abstract: An implantable receiver (12) is powered and controlled by an external (not-implanted) transmitter (14) when a transmitter coil (22) is properly aligned with a receiver coil (20). No magnets are used in either the transmitter or receiver to achieve and maintain the needed alignment. Rather, a special set of implant tools (50) are used to assure that alignment is achieved and maintained between the implantable receiver (12) and external transmitter (14) when the implant operation is carried out. A preferred embodiment of the invention provides a magnetless implantable cochlear stimulator (ICS) (40) and a corresponding magnetless headpiece (30) worn behind the ear.

Abstract: An implantable electrode array, adapted for insertion into a cochlea, provides improved stability of electrode contact direction. In-line electrodes are spaced-apart along one side of a flexible carrier. The structure of the electrode array facilitates bending of the array with the electrode contacts on the inside of the bend, yet deters flexing or twisting of the array in other directions. The electrode contacts preferably are each made from two strips of metal, arranged in a "T" shape (top view). During assembly, all of the "T" strips are held in position on an iron sheet. Two wire bundles are formed that pass along each side of each "T". The leg of each "T" is folded over to pinch at least one of the wires from one of the wire bundles therebetween. This pinched wire is then resistance welded to the strip. The sides of the "T" are then folded up and touch or nearly touch to form a ".DELTA." shape (side view). The wire bundles going to more distal electrodes pass through the ".DELTA.

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.