Abstract: A system and method that facilitates stimulating neural pathways, e.g., muscles and/or associated nerves, of a patient's body for the purpose of therapeutic medical treatment by rehabilitating weakened muscles and using neuroplasticity to retrain sequential muscle movements and/or to provide the ability to directly deliver functional motor movements. Use of the present invention is of particular value for treating a patient following a stroke. More particularly, such systems are characterized by a plurality of discrete devices, preferably battery powered but may alternatively include RF-powered devices as well or in combination, configured for implanting within a patient's body via injection, each device being configured to affect a parameter, e.g., via nerve and/or muscle stimulation and/or to sense a body parameter, e.g., temperature, O2 content, physical position, electrical potential, etc.

Abstract: A DC to DC transmission system includes at least three conductors between a source and a sink, a first switch which alternately connects each conductor to the source, a second switch which alternately connects each conductor to the sink. The switches are synchronized such that one conductor is alternately coupled between the same polarity side of the source and sink and another conductor is alternately coupled between the other polarity side of the source and sink. The alternating connection between the conductors and source and sink may be undertaken at a wide range of frequencies.

Abstract: System and apparatus for measuring pressure comprising a microelectronic device, an interface member attached to the microelectronic device, a pressure sensor having a diaphragm responsive to external pressure exerted upon the diaphragm, wherein the interface member is positioned between the microelectronic device and the pressure sensor and is attached to the pressure sensor providing a first cavity between the pressure sensor diaphragm and the interface member and wherein the pressure in the first cavity is set at an initial predetermined pressure.

Abstract: A system and method that facilitates multiple systems of communicating devices, i.e., a master device and one or more implantable slave devices, to coexist on a common, e.g., RF, communication channel having a limited temporal bandwidth while maintaining the required update rate between each master device and its associated slave devices. In embodiments of the present invention, master devices periodically transmit one or more beacon messages that are suitable for identification by other such master devices at a communication range greater than the communication range that may cause interference between systems and thus enabling one or more systems to cause the position of its frame periods to be interleaved with the frame periods of other such systems in anticipation of systems moving in closer proximity and actually interfering with each other.

Abstract: A system, method and power/data transmission device comprising a coil having a high Q, a low-voltage driver and a high-voltage driver switchably coupled to the coil. The low-voltage driver and the high-voltage driver are controlled by a microcontroller and switch at about the same time thereby providing a modulated data signal for transmission. Furthermore, the system includes at least one implantable microstimulator coupled to the transmission device.

Abstract: An amplifier circuit is disclosed that allows for practical integrated circuit implementation of a dc-blocked, low-noise differential amplifier capable of amplifying ultra low-frequency signals and amplitudes ranging upwards of a few microvolts. DC-blocking capacitors having a capacitance value close to that of the effective input capacitance of the low-noise amplifier's inputs can be used by incorporating a positive feedback mechanism that tracks any variations in the amplifier gain or integrated circuit's technology process and lowers or cancels the input parasitic capacitances. Advantageously, the parasitic capacitance of transistors, typically field effect transistors, located on an integrated circuit chip are used in the feedback mechanism. This reduces the capacitive voltage division loss of the signal at the input of the amplifier while still allowing for the use of very small values of dc-blocking capacitance.

Abstract: System and apparatus for measuring pressure including a microelectronic device, an interface member attached to the microelectronic device, a pressure sensor having a diaphragm responsive to external pressure exerted upon the diaphragm, wherein the interface member is positioned between the microelectronic device and the pressure sensor and is attached to the pressure sensor providing a first cavity between the pressure sensor diaphragm and the interface member and wherein the pressure in the first cavity is set at an initial predetermined pressure.

Abstract: A method for treating shoulder subluxation using an implantable device to stimulate the axillary nerve which in turn activates sensory fibers to relieve shoulder pain and activates deltoid muscle to treat disuse atrophy and possibly augment any weakened voluntary movements. Known stimulation devices are either (1) external requiring surface electrodes or (2) implantable located directly into the deltoid muscle allowing stimulation of the proximate motor-points; each requiring relatively large stimulus currents and neither directly dealing with the pain resulting from the shoulder subluxation. In the present invention, a device is implanted via injection or open surgery proximate to the axillary nerve. Advantageously, the nerve branches into portions that stimulate the deltoid muscle and pass sensory signals. By stimulating the axillary nerve (1) a lower stimulus signal level can be used and (2) pain may be blocked while treating the atrophied deltoid muscle and augmenting weakened voluntary movements.

Abstract: An implantable device and a wireless communication integrated circuit (IC) implementable in the implantable device for communicating with a remote unit, wherein the communication IC is capable of self-initializing, namely initial booting without requiring an external general booting program to force the booting process. Moreover, the implantable device and the communication IC provide for checking of the validity and integrity of any program instructions received from the remote unit for the desired operation of the implantable device. The implantable device and the communication IC therein have power-saving capability in order to extend the operation of the implantable device between battery charges. A further embodiment provides a robust communication IC, whereby signal distortion or interference between the analog and digital components collectively residing on the same communication IC is minimized or eliminated.

Abstract: A housing for an implantable medical device in the shape of a hollow magnetic field concentrating tube about which an electrically conductive wire coil is wound and within which medical device electronics is housed. The tube, preferably made of ferrite, is encased in a protective sleeve formed of a material that is impervious to body fluids. The coil provides an electrical output as a result of being exposed to a varying magnetic field that is concentrated around the coil by virtue of the field concentrating tube. The output of the coil is utilized as part of a power supply for the medical device electronics. The sleeve has a generally cylindrical cross-section having an outside diameter of about 3.175 mm and an axial length in the range of about 3.2 mm to 8 mm.

Abstract: An implantable device comprising a sensing unit, wherein the sensing unit is adapted to rectify biological/neurological signals in the form of sensed electrical signals from body tissue adjacent to the location of the implantable device. The sensing unit of the implantable device comprises at least one amplifier, wherein the supply current to the at least one amplifier is responsive to the magnitude of the sensed electrical signals provided to the at least one amplifier. The implantable device is further capable of integrating the rectified sensed electrical signals and generating output signals, wherein the output signals contain indicia of biopotential parameters of the body tissue.

Abstract: A circuit may be tuned to resonate at a driving frequency. The circuit includes a source that provides an output at a drive frequency and a resonant circuit having an input coupled to the source, an output, and first and second selectable resonant frequencies. The first resonant frequency is below the drive frequency and the second resonant frequency is above the drive frequency. A control coupled to the resonant circuit output selects the first and second resonant frequencies to cause the resonant circuit to provide an output at an apparent resonant frequency equal to the drive frequency.

Abstract: An oxygen monitoring system measures the oxygen concentration in a patient's blood for use as a physiological control parameter in rate responsive pacing. The oxygen monitoring system includes an oxygen monitoring circuit embedded in a cardiac stimulation lead and monitors the blood oxygen in a patient's venous system that passes through and into the lead. The oxygen monitoring circuit includes a working electrode, a counter electrode, a reference electrode and an IC chip electrically interconnected between the electrodes and programmed to carry out an oxygen concentration measuring process. Oxygen surrounding the electrodes causes current to flow between the electrodes and the IC chip varies the value of current generated by a current source coupled between the working electrode and counter electrode in a manner to maintain the voltage between the working electrode and reference electrode at a preselected value. The variation of the current source value is a direct measure of the blood oxygen concentration.

Abstract: A method and apparatus for protecting an electronic implantable medical device prior to it being implanted in a patient's body. The apparatus affords protection against electronic component damage due to electrostatic discharge and/or physical damage due to improper handling. The apparatus is comprised of a circuit board having a conductive surface for receiving and releasably grasping the electrodes of the medical device to support the device's housing proximate to the surface of the circuit board. Two conductive paths are formed on the circuit board extending between two conductive surfaces for shunting electrostatic discharge currents to prevent such currents from passing through the device's electronic circuitry. The conductive paths include oppositely oriented diodes, preferably comprising diodes which emit light (i.e., LEDs) when current passes therethrough. Additionally, an external monitor/generator is provided to enable functional testing of the medical device.

Abstract: A full-body charger for charging one or more battery-powered devices wherein such devices are configured for implanting beneath a patient's skin for the purpose of tissue, e.g., nerve or muscle, stimulation and/or parameter monitoring and/or data communication. Devices in accordance with the invention include a support structure, typically chair-shaped or bed-shaped, capable of supporting a patient's body while providing a magnetic field to one or more of the implanted devices using one or more coils mounted within for providing power to the implanted devices. Consequently, in a preferred embodiment, a single, generally sequential, charging cycle can charge all of the implanted devices and thus minimize the charge time requirements for a patient and accordingly improve the patient's life style.

Abstract: An automatic tuning system for a magnetic field generating tuned circuit includes a processor configured to maintain the resonant frequency of a tuned circuit equal to a reference frequency. The tuned circuit is driven by a power amplifier whose output provides an amplified signal at the reference frequency. The tuned circuit includes a magnetic field generating inductor and a bank of individually switchable capacitors controlled by the processor capable of adding and removing the respective capacitances to and from the tuned circuit. The inductor includes a Faraday shield to shield the tuned circuit from the influence of electric fields. A power sense circuit monitors the power delivered by the power amplifier to the tuned circuit and the processor sequentially switches the capacitors in a binary progression format to achieve maximum power delivery indicative of conforming the resonant frequency of the tuned circuit to the reference frequency.

Abstract: An improved telemetry system for telemetering data from an implantable device such as a heart pacemaker to an external device with minimum energy consumption. The external device first sweeps its receiver across a predetermined frequency band, e.g., the fm broadcast band of 88 MHz to 108 MHz, to determine the particular frequency having the lowest ambient electromagnetic noise level, which it deems the optimum frequency for the telemetry to occur. The external device's transmitter then commands the pacemaker to telemeter a predetermined start signal at a succession of frequencies that sweep across that same frequency band, while the external device's receiver remains tuned to the optimum frequency. Eventually, the external devices receiver will receive the start signal and the external device thereupon will command the pacemaker to thereafter remain at its current frequency for the subsequent telemetry of data.

Abstract: An expanded screen current collector is provided with side edges coined inwardly to prevent sharp tines formed along the side edges from damaging adjacent components within the electrochemical cell. The expanded screen current collector is formed by cutting a thin flat sheet of current collector material, such as titanium or stainless steel, to have a height somewhat greater than a height required for use within the electrochemical cell. The current collector material is cut and expanded, then the side edges are coined inwardly by an amount sufficient to reduce the height of the resulting expanded screen current collector to a height appropriate for use within the electrochemical cell. An active cathode material, such as polycarbonmonoflouride, is coated onto side surfaces of the expanded screen current collector. An electrode structure employing the expanded screen current collector having the coined edges is also described.

Abstract: A pacing lead having a stylet introduced anti-inflammatory drug delivery element advanceable from the distal tip electrode. The element is preferably formed as a moldable biocompatible composite material. The element has a biocompatible matrix material which may be combined with drugs and therapeutic agents to deliver the drugs and agents by co-dissolution or diffusion to the point of either passive or active fixation. The drug delivery element may be rigid and serve to center the means, preferably a helix, for active fixation of the lead in the myocardium.

Abstract: A cardiac device that stores physiological sensor data from multiple sensors is provided. A patient may use a portable triggering device to cause the cardiac device to store the data when the patient experiences symptoms that appear to be due to an abnormal heart condition. Alternatively, the data may be stored when the cardiac device identifies an abnormal physiological condition. A physician may select which sensors are used to store the data and may also adjust the number of memory buffers in which the data is to be stored.