171 results about "Stimulus pulse" patented technology

A method of determining relative neuro-muscular response onset value thresholds for a plurality of spinal nerves, comprising: depolarizing a portion of the patient's cauda equina; and measuring the current intensity level at which a neuro-muscular response to the depolarization of the cauda equina is detected in each of the plurality of spinal nerves. A method for detecting the presence of a nerve adjacent the distal end of at least one probe, comprising: determining relative neuro-muscular response onset values for a plurality of spinal nerves; emitting a stimulus pulse from a probe or surgical tool; detecting neuro-muscular responses to the stimulus pulse in each of the plurality of spinal nerves; and concluding that the electrode disposed on the distal end of the at least one probe is positioned adjacent to a first spinal nerve when the neuro-muscular response detected in the first spinal nerve is detected as a current intensity level less than or equal to a corresponding neuro-muscular response onset value of the first spinal nerve.

A stimulator for stimulating the leg or other parts of the body e.g. the leg in a patient with drop foot is provided, the stimulator being controlled by e.g a foot switch but being reliable in use and therefore commanding acceptance by users. The foot switch has to work in adverse environmental conditions and is subject to repeated use so that its characteristics vary with time. The invention provides a functional electrical stimulator for attachment to the leg that has adaptive characteristics and comprises first and second electrodes for attachment to the leg to apply an electrical stimulus, a foot switch for sensing foot rise or foot strike, a circuit responsive to said foot switch for generating stimulation pulses; and means forming part of said circuit for responding to changes in the resistance characteristics of said switch means by adjusting a corresponding response threshold of said circuit.The invention also provides a two-channel stimulator that offers various possibilities for controlling the signals to be supplied to different muscle groups. For example, means may be provided defining a signal pathway between the first and second channels so that the supply of stimulation pulses in one of said first and second channels can be controlled by the state of switch means associated with the other of said first and second channels. In a further embodiment means defining a signal pathway between the first and second channels is arranged so that the supply of stimulation pulses in one of said first and second channels can be controlled by the state of activity of the other of said first and second channels. In a yet further embodiment the first channel has means arranged to cause the stimulation pulses to time-out after a predetermined period and the second channel having no or disabled timing means so that supply of stimulation pulses is continuous in a predetermined state of limb position responsive switch means associated with that channel. The two-channel stimulator can be used e.g., to treat bilateral dropped foot.

Apparatus and method for stimulating neuromuscular tissue in the stomach. The neuromuscular stimulator stimulates the neuromuscular tissue by applying current-controlled electrical pulses. A voltage sensor detects the voltage across the neuromuscular tissue to determine if the voltage meets a predetermined voltage threshold. A control circuit adjusts the current-controlled pulse if the voltage is found to meet the voltage threshold, such that the voltage does not exceed the voltage threshold. A voltage-controlled pulse may also be applied to the tissue. A current sensor would then detect whether the current on the neuromuscular tissue meets a predetermined current threshold, and a control circuit adjusts the voltage controlled pulse such that the current does not exceed the current threshold. A real time clock may be provided which supplies data corresponding to the time of day during the treatment period. A programmable calendar stores parameters of the stimulating pulse, wherein the parameters have a reference to the time of day.

A method of determining relative neuro-muscular response onset value thresholds for a plurality of spinal nerves, comprising: depolarizing a portion of the patient's cauda equina; and measuring the current intensity level at which a neuro-muscular response to the depolarization of the cauda equina is detected in each of the plurality of spinal nerves. A method for detecting the presence of a nerve adjacent the distal end of at least one probe, comprising: determining relative neuro-muscular response onset values for a plurality of spinal nerves; emitting a stimulus pulse from a probe or surgical tool; detecting neuro-muscular responses to the stimulus pulse in each of the plurality of spinal nerves; and concluding that the electrode disposed on the distal end of the at least one probe is positioned adjacent to a first spinal nerve when the neuro-muscular response detected in the first spinal nerve is detected as a current intensity level less than or equal to a corresponding neuro-muscular response onset value of the first spinal nerve.

An implantable cardiac rhythm management device operable in an autothreshold or autocapture verification mode, wherein the rhythm management device is capable of detecting noise that affects signal characteristics of a sensed intracardial evoked response electrogram signal. The device includes a noise detection circuit that determines whether a minimum peak timing occurs during a predetermined time following delivery of a stimulation pulse. If a minimum peak timing occurs during the predetermined time following delivery of the stimulation pulse, then significant amounts of noise affecting the signal characteristics of the electrocardiogram signal is assumed.

A percutaneous, intramuscular stimulation system for therapeutic electrical stimulation of select muscles of a patient includes a plurality of intramuscular stimulation electrodes (50) for implantation directly into select muscles of a patient and an external battery-operated, microprocessor-based stimulation pulse train generator (10) for generating select electrical stimulation pulse train signals (T). A plurality of insulated electrode leads (40) percutaneously, electrically interconnect the plurality of intramuscular stimulation electrodes (50) to the external stimulation pulse train generator (10), respectively. The external pulse train generator (10) includes a plurality of electrical stimulation pulse train output channels (E) connected respectively to the plurality of percutaneous electrode leads (40) and input means (24,26,28) for operator selection of stimulation pulse train parameters (PA,PD,PF) for each of the stimulation pulse train output channels (E) independently of the other channels. Visual output means (20) provides visual output data to an operator of the pulse train generator (10). Non-volatile memory means (66,68) stores the stimulation pulse train parameters for each of the plurality of stimulation pulse train output channels (E). The generator (10) includes means for generating stimulation pulse train signals (100,102) with the selected pulse train parameters on each of the plurality of stimulation pulse train output channels (E) so that stimulus pulses of the pulse train signals having the select stimulation pulse train parameters pass between the intramuscular electrodes (50) respectively connected to the stimulation pulse train output channels (E) and a reference electrode (52).

A CARS system and method for probing a Raman signature of a sample are described. A short femtosecond pulse from one or more lasers is split into two pulses, a stimulus pulse and a probe pulse, whereby the probe pulse is time-delayed with respect to the stimulus pulse. Both pulses can be phase- and polarization-modulated. The stimulus pulse excites a vibronic level in the sample and the probe pulse probes molecular Raman transitions in the sample. A difference in the signals with and without excitation can be used to determine on which molecule a bond is most likely located. This will allow an accurate and sensitive determination of the presence of specific molecules in the sample. The system and method can be used to analyze biological samples and to discriminate between molecules having overlapping Raman signatures.

Apparatus and method for stimulating neuromuscular tissue in the stomach. The neuromuscular stimulator stimulates the neuromuscular tissue by applying current-controlled electrical pulses. A voltage sensor detects the voltage across the neuromuscular tissue to determine if the voltage meets a predetermined voltage threshold. A control circuit adjusts the current-controlled pulse if the voltage is found to meet the voltage threshold, such that the voltage does not exceed the voltage threshold. A voltage-controlled pulse may also be applied to the tissue. A current sensor would then detect whether the current on the neuromuscular tissue meets a predetermined current threshold, and a control circuit adjusts the voltage-controlled pulse such that the current does not exceed the current threshold. A real time clock may be provided which supplies data corresponding to the time of day during the treatment period. A programmable calendar stores parameters of the stimulating pulse, wherein the parameters have a reference to the time of day.

The invention provides a method and device for inducing a conditioned neural response in a subject. The method comprises detecting spike activity in a first neural site in the subject; and delivering a stimulus pulse to a second neural site in the subject. The stimulus pulse is delivered within the time window for synaptic strengthening following the detecting of a spike. These two steps, detection and stimulation, are repeated continuously, typically for a day or two. The conditioned neural response is induced when a pattern of neural activity evoked by stimulation at the first neural site emulates a pattern of neural activity evoked by stimulation at the second neural site. The conditioned neural response persists for an extended period of time.

This invention relates to an electrotherapeutic device useful for treating a variety of aspects associated with Carpal Tunnel Syndrome. The device is a TENS-like unit that is miniaturized, comfortable and unobtrusive, thereby allowing for unencumbered performance of daily activities. The device houses an electronic circuit comprising optimally placed electrodes and a microprocessor preprogrammed to deliver an optimal stimulus pulse protocol whereby the stimulus pulse parameters are varied so as to deliver a series of stimulus pulses for treating all aspects of CTS, including but not limited to pain blockage, nerve regeneration, reduction in inflammation and biochemical release.

A method and associated stimulation device for ensuring firing of an action potential in an intended physiological target activated by a stimulus pulse generated by an electrode of a non-invasive surface based stimulation device irrespective of skin-to-electrode impedance by: (i) increasing internal impedance of the stimulation device so as to widen a Chronaxie time period thereby ensuring firing of the action potential of the intended physiological target irrespective of the skin-to-electrode impedance; and / or (ii) generating a stimulation waveform that optimizes a non-zero average current (e.g., non-zero slope of the envelope of the stimulation waveform) during preferably substantially the entire current decay of the stimulus pulse.

A neurostimulation system comprising stimulation output circuitry configured for delivering stimulation pulses to target tissue in accordance with a set of stimulation parameters. The neurostimulation system comprises monitoring circuitry configured for continuously measuring action potentials evoked in the target tissue in response to the delivery of the stimulation pulses to the target tissue, memory configured for storing a characteristic of a reference evoked action potential, and at least one processor configured for initiating an automatic mode, in which a characteristic of the measured evoked action potentials is compared to the corresponding characteristic of the reference evoked action potential, and one or more stimulation parameter values in the set of stimulation parameters are adjusted to decrease or increase the energy level of the stimulation pulses, thereby evoking action potentials in the target tissue having substantially the same corresponding characteristic as the reference evoked action potential.

A fully implantable cochlear prosthesis includes (1) an implantable hermetically sealed case wherein electronic circuitry, including a battery and an implantable microphone, are housed, (2) an active electrode array that provides a programmable number of electrode contacts through which stimulation current may be selectively delivered to surrounding tissue, preferably through the use of appropriate stimulation groups, and (3) a connector that allows the active electrode array to be detachably connected with the electronic circuitry within the sealed case. The active electrode array provides a large number of both medial and lateral contacts, any one of which may be selected to apply a stimulus pulse through active switching elements included within the array. The active switching elements included within the array operate at a very low compliance voltage, thereby reducing power consumption. The entire prosthesis is very efficient from a power consumption standpoint, thereby allowing a smaller battery to power the system for longer periods of time before recharging or replacement is required. The hermetically sealed case within which the electronic circuitry, battery, and microphone are housed may be replaced, when needed, through minimally invasive surgery. Further, the electronic circuitry housed within the hermetically sealed case may be programmed, as needed, using acoustic and / or RF control signals. In one embodiment, such control signals may be realized using phase-shift keyed (PSK) modulation of an acoustic signal within a very narrow frequency band centered at about 6 KHz.

An intra-pericardial medical device is provided that comprises a lead body having a proximal portion, a distal end portion, and an intermediate portion extending between the proximal portion and the distal end portions. An intra-pericardial medical device further includes the control logic housed with the lead body and an energy source housed within the lead body. A stimulus conductor is included and extends along the lead body. An electrode is joined to the stimulus conduct near the distal end portion, where the electrode configured to deliver stimulus pulses. A telemetry conductor is provided within the lead and extends from the proximal portion and along the intermediate portion of the lead body. The telemetry conductor is wound into a series of coil groups to form inductive loops for at least one of receiving and transmitting radio frequency (RF) energy.

Amplification of an evoked potential signal is carried out utilizing a high pass filter implemented as an integrator in a feedback loop which drives the DC offset voltage to zero. As a result, the feed-forward amplifier circuit has almost zero volts at its output since the only voltage remaining is the offset voltage of the operational amplifier, which is selected so as to maintain this parameter as low as possible. Because the voltage impressed across the feed-forward amplifier section is close to zero, the gain of this section can be set to zero during the time that the electrical stimulus pulse is present without introducing any additional artifacts and subsequent amplifier stages are not driven into saturation. When the electrical stimulus potential is no longer present or is significantly reduced in amplitude and before the time of receipt of the response signal, the feed-forward amplifier is brought back into the circuit to provide the high gain required to amplify the response signal, which can be measured without interference from saturation of any of the amplifier stages as they recover to baseline.

A portable apparatus which allows a user to perform self-diagnostic evaluation of nerve sensory latency between a pair of epidermal locations proximal to nerve conduction paths. The device provides a simple and low-cost self-diagnostic apparatus which may be used for the detection and ongoing monitoring of sensory latency, such as sensory latency which is the result of carpal tunnel syndrome. The apparatus is powered by a single battery which provides power to all circuitry of the apparatus. Upon power activation, the device generates a series of high voltage stimulus pulses at an electrode in epidermal contact with the user / operator. The nerve response voltage is detected by a second electrode located along nerve pathway and the time delay between stimulus and response is displayed and periodically updated as each new response is detected.

An implantable electroacupuncture device (IEAD) treats a medical condition of a patient through application of electroacupuncture (EA) stimulation pulses applied at a target tissue location, such as an acupoint. The IEAD comprises an implantable, coin-sized, self-contained, leadless electroacupuncture device having at least two electrodes attached to an outside surface of its housing. The device generates EA stimulation pulses in accordance with a specified stimulation regimen. Power management circuitry within the device allows a primary battery, having a high internal impedance, to be used to power the device. The stimulation regimen generates stimulation pulses during a stimulation session of duration T3 minutes applied every T4 minutes. The duty cycle, or ratio T3 / T4, is very low, no greater than 0.05. The low duty cycle and careful power management allow the IEAD to perform its intended function for several years.

A CARS system and method for probing a Raman signature of a sample are described. A short femtosecond pulse from one or more lasers is split into two pulses, a stimulus pulse and a probe pulse, whereby the probe pulse is time-delayed with respect to the stimulus pulse. Both pulses can be phase- and polarization-modulated. The stimulus pulse excites a vibronic level in the sample and the probe pulse probes molecular Raman transitions in the sample. A difference in the signals with and without excitation can be used to determine on which molecule a bond is most likely located. This will allow an accurate and sensitive determination of the presence of specific molecules in the sample. The system and method can be used to analyze biological samples and to discriminate between molecules having overlapping Raman signatures.

An apparatus and method for electrical charge balancing when generating a stimulus during functional neural stimulation is presented. A stimulus pulse is generated (cathodic or anodic), and after a selected delay a charge compensating pulse is generated of an opposite polarity. The electrode circuit discontinuously examines electrode voltage after termination of the stimulus pulse, and utilizes this voltage to determine how long to extend the width of the charge compensating pulse. The electrode circuit thus performs accurate electrical charge cancellation to remove residual charges from the electrode by precisely controlling pulse width for an opposing polarity compensating pulse that need not have the same current level as the stimulus pulse.

The external event detection device comprises an electronic unit (22) and an external event sensor (16), the electronic unit having at least a non-volatile memory cell (24, T1) in which data relative to at least one external event detected by the external event sensor can be stored. According to the invention, the external event sensor defines an energy harvester that transforms energy from said at least one external event into electrical energy contained in an electrical stimulus pulse provided to the electronic unit. The electronic unit is arranged for storing said data by using only the electrical energy contained in the electrical stimulus pulse. In particular, the non-volatile memory cell is directly set to its written logical state from its initial logical state by the electrical stimulus pulse provided by said energy harvester. In a preferred embodiment, the electronic unit further comprises a set circuit (26) comprising a second FET transistor (T2) arranged between the ground of the electronic unit and the drain of a first FET transistor (T1) defining the non-volatile memory cell, this switch having a control gate connected to the control gate of the first FET transistor. The second FET transistor is turned on when an electrical stimulus pulse is provided to the electronic unit, connecting the drain (DRN) of the first FET transistor (T1) to ground and thus allowing the secure setting of the non-volatile memory cell.

An implantable medical device includes a lead, a monitoring module, a multi-function conductive (MFC) coil, and a field detection module. The monitoring module identifies cardiac events based on the cardiac signals and directs stimulus pulses to be delivered to the heart through one or more electrodes connected to the lead. The MFC coil has an electric characteristic that varies based on exposure of the coil to an external magnetic field. The field detection module detects exposure of the coil to the external magnetic field by applying a field detection signal to the coil and identifying a change in the electric characteristic of the MFC coil. The field detection module switches operation of the monitoring module to an MR safe mode based on the change that is identified.

The invention provides a multi-channel FES (Functional Electrical Stimulation) synchronous walking aid. The multi-channel FES synchronous walking aid comprises a hose, a trigger and an electrode; a stimulator connected to the electrode and a synchronous controller connected to the trigger are arranged in the host so as to form an electrical stimulation close-loop control circuit for tracking gait actions of the diseased limb. In the hose, a plurality of timing sequence operation control module arranged in the synchronous controller are nested in each other and inserted in two foot control trigger elements of the trigger by use of a wiring harness, and used for alternatively switching the operations of walking timing sequences and synchronously controlling stimulation pulse sequences output by the stimulator. The stimulator is provided with a low-frequency pulse circuit module and a stimulation pulse power-driven circuit module, the two of which are inserted in four groups of electrodes A, B, C and D by use of a wiring harness to stimulate the actions of the diseased limb. The main controller comprises an operating interface, a memory, a single chip and a control program thereof. The synchronous walking aid is capable of stimulating the diseased limb so that the diseased limb is off the ground to exercise gait actions, and also helping a patient with walking on the ground; the synchronous walking aid can be applied independently to stimulate the diseased limb of one single side, and two aids can be liked to stimulate the diseased limbs of two sides to act alternately and cooperatively.