Abstract: Methods and systems for measuring tissue impedance and monitoring PVD treatment using neuro-implants with improved wireless powering are disclosed. In some embodiments, an implanted device including a wireless energy receiver, a demodulation circuit, and electrodes may be configured to received modulated energy from an energy transmitter. The implanted device may convert the energy to an electrical voltage to be applied to tissue to adjust the tissue's impedance. The tissue impedance may be measured with a computing system by receiving and processing an energy signal emitted/produced in response to the electrical voltage applied by the implanted device. In some embodiments, improved microwave powering schemes may be utilized to power the implanted device. In some embodiments, improved ultrasound powering schemes may be utilized to power the implanted device.

Abstract: A system for providing neurostimulation includes an external device (“external exciter”) and an implanted device. The external exciter includes an energy source which inductively powers the implanted device. Examples of such external exciters include devices having at least one of: ultrasonic transducers, Radio Frequency (RF) transmitters, and solar cells. The implanted device includes circuitry that limits its maximum energy output to a predetermined saturation threshold such that excess stimulation from the external exciter does not raise the output of the implanted device beyond the saturation threshold. The output signal of the external exciter is then pulse-width modulated in order to produce a desired amount of output stimulation from the implanted device to stimulate the bioelectrically excitable tissue at a desired level.

Abstract: A system for providing neurostimulation includes an external device (“external exciter”) and an implanted device. The external exciter includes an energy source which inductively powers the implanted device. Examples of such external exciters include devices having at least one of: ultrasonic transducers, Radio Frequency (RF) transmitters, and solar cells. The implanted device includes circuitry that limits its maximum energy output to a predetermined saturation threshold such that excess stimulation from the external exciter does not raise the output of the implanted device beyond the saturation threshold. The output signal of the external exciter is then pulse-width modulated in order to produce a desired amount of output stimulation from the implanted device to stimulate the bioelectrically excitable tissue at a desired level.

Abstract: Methods and apparatuses for speeding the softening of the cervix (cervical ripening) by way of application of ultrasound energy. A vaginal transducer may be used to emit pulse-modulated ultrasound energy directed to the cervix. Focused ultrasound energy may be applied trans-abdominally and directed at the cervix. Ultrasound energy is widely used in medical applications such as diagnostic imaging, therapeutic heating and noninvasive surgery.

Abstract: A method for ultrasound modulation of the brain for treatment of stroke, brain injury, and other neurological disorders or the improvement of cognitive functioning in patients. The method may include identifying a stimulation site of a brain, where the stimulation site is associated with a brain disorder, applying ultrasound to the stimulation site, and initiating physical therapy. Alternately, ultrasound may be applied to the brain to enhance aspects of cognitive functioning by the combination of exercising the functionality of the brain and applying ultrasound to the region(s) or structures of the brain known to be associated with that function.

Abstract: An apparatus, system, and method for neurostimulation by high frequency ultrasound. In one embodiment, an apparatus includes a pulse generator, an ultrasound transducer coupled to the pulse generator, and an implantable stimulator. The implantable stimulator may include a piezoelectric element configured to convert ultrasound signals from the ultrasound transducer into electrical signals, a rectifier configured to convert alternating current from the piezoelectric element to a monophasic current, a capacitor coupled to the rectifier, and a first electrode and a second electrode coupled to the rectifier and capacitor and configured to transmit the monophasic current to body tissue. In addition, the apparatus may include a current-limiting circuit configured to limit the amount of current transmitted to the body tissue.

Abstract: A system for providing neurostimulation includes an external device (“external exciter”) and an implanted device. The external exciter includes an energy source which inductively powers the implanted device. Examples of such external exciters include devices having at least one of: ultrasonic transducers, Radio Frequency (RF) transmitters, and solar cells. The implanted device includes circuitry that limits its maximum energy output to a predetermined saturation threshold such that excess stimulation from the external exciter does not raise the output of the implanted device beyond the saturation threshold. The output signal of the external exciter is then pulse-width modulated in order to produce a desired amount of output stimulation from the implanted device to stimulate the bioelectrically excitable tissue at a desired level.

Abstract: Methods and systems for neurostimulation and/or neurotelemetry of electrically-excitable biological tissue. Embodiments include implanting single or multiple semiconductor diodes and applying a high frequency electrical volume current. Neurostimulation embodiments include local rectification of the volume current by the diode, which can provide a pulsating electrical waveform capable of locally stimulating neural tissue, hi neurotelemetry embodiments, semiconductor diodes can be placed in contact with excitable tissue and a low level electrical carrier wave can be passed through the tissue and implanted diode whereby low level tissue bioelectric events intermodulate with the carrier wave and encode bioelectrical effects.

Abstract: Methods and systems for neurostimulation and/or neurotelemetry of electrically-excitable biological tissue. In one embodiment, a method includes providing a radio frequency output to a diode implanted in biological tissue. The radio frequency output cause current to flow in the diode that is sufficient to provide neurostimulation. Additionally, a radio frequency receiver is configured to receive a second harmonic signal from the diode, which can be used to control the radio frequency output.

Abstract: Apparatus, systems, and methods for current monitoring in ultrasound powered neurostimulation. The apparatus may include an ultrasound transmitter configured to emit an ultrasound output directed at a piezoelectric device implanted in biological tissue. The apparatus may also include a detector configured to detect an induced current in response to the ultrasound output in the biological tissue. The piezoelectric device may include a piezoelectric material and a diode. The apparatus may include a feedback mechanism to control the amount of induced current in the biological tissue.

Abstract: Methods and systems for neurostimulation and/or neurotelemetry of electrically-excitable biological tissue. In one embodiment, a method includes providing a radio frequency output to a diode implanted in biological tissue. The radio frequency output cause current to flow in the diode that is sufficient to provide neurostimulation. Additionally, a radio frequency receiver is configured to receive a second harmonic signal from the diode, which can be used to control the radio frequency output.

Abstract: Methods and devices for stimulating nerves are disclosed. In one embodiment adapted for stimulating excitable tissue, the invention includes drive circuitry, an acoustic transducer and a pair of electrodes.

Abstract: Methods and systems for neurostimulation and/or neurotelemetry of electrically-excitable biological tissue. Embodiments include implanting single or multiple semiconductor diodes and applying a high frequency electrical volume current. Neurostimulation embodiments include local rectification of the volume current by the diode, which can provide a pulsating electrical waveform capable of locally stimulating neural tissue, hi neurotelemetry embodiments, semiconductor diodes can be placed in contact with excitable tissue and a low level electrical carrier wave can be passed through the tissue and implanted diode whereby low level tissue bioelectric events intermodulate with the carrier wave and encode bioelectrical effects.

Abstract: The present embodiments provide an apparatus, system, and method for ultrasound powered neurotelemetry. In one embodiment, the apparatus includes a piezoelectric element configured to receive an ultrasonic pulse and convert the electronic pulse into an electric potential. A diode may be coupled to the piezoelectric element, the diode configured to cause an electric current to flow in response to the electric potential. The apparatus may additionally include a reference electrode and a stimulating electrode coupled to the diode. The reference electrode may sense bioelectric activity in a region of body tissue located in proximity to the reference diode. The stimulating electrode may emit a carrier signal, wherein the carrier signal is modulated in response to the bioelectric activity sensed by the reference electrode.

Abstract: Methods and devices for stimulating nerves are disclosed. In one embodiment adapted for stimulating excitable tissue, the invention includes drive circuitry, an acoustic transducer and a pair of electrodes.

Abstract: The invention relates to wireless biotelemetry of low level bioelectric and biosensor signals by means of directly modulating the backscatter of a resonant circuit. Low level electrical analog or digital signals are directly applied to a resonant circuit containing a voltage-variable capacitor such as a varactor diode, that proportionally shifts the resonant frequency and so amplitude of radiofrequency backscatter in a way that represents analog bioelectric or biosensor waveform data. By strongly driving the resonant circuit with a radiofrequency source, a voltage variable capacitance can be caused to amplify the bio-signal level by a parametric process and so provide sufficient sensitivity to telemeter for low millivolt and microvolt level signals without additional amplification. A feature of the device is its simplicity and that it accomplishes both modulation and preamplification of low level sensor signals by the same variable capacitance circuit which reduces the device size and power consumption.

Abstract: A biochemical sensor is provided for measuring the concentration of a chemical dissolved within a fluid by providing a differential voltage proportional to a temperature differential resulting from the heat evolved from the enzymatic reaction of the chemical under test. The biochemical sensor is formed by depositing thin films of two dissimilar metals upon a substrate using microelectronic fabrication techniques. A multiplicity of thermocouple junctions are created at the intersections of the two dissimilar metal films, and the resulting series-connected thermocouple junctions are alternately designated sensing and reference junctions. The sensing junctions, but not the reference junctions, are covered by an enzyme, catalyst, or other species for initiating a chemical reaction involving the chemical under test, giving rise to a temperature differential between the sensing and reference junctions proportional to the concentration of the chemical under test.

Abstract: An anisotropic hollow fiber membrane is utilized to sample fluids for selected substances by convective flow of liquid and such substances, with conduct of the liquid to a sensor for analysis for such substances, to permit monitoring, particularly of body fluids, for such substances with short response times.

Abstract: An arrangement for noninvasively detecting both alternating and direct biocurrents in a living organism applies a magnetic field to the organism, such that a biocurrent flowing in the organism interacts with the applied magnetic field to generate a force in the tissue of the organism at the location of the biocurrent, producing an acoustic response thereat. The acoustic response is detected by placing at least one acoustic transducer detector, such as a microphone, in proximity to the organism, such that the detected acoustic response corresponds to the biocurrent. The applied magnetic field can be generated by a circular array of magnetic field generators placed symmetrically about the organism. The applied magnetic field can be rotated relative to the organism by selectively energizing opposite pairs of magnetic field generators in sequence.