Abstract: Tools and methods for creating isolated or localized temperature changes on components in an electric circuit. By isolating temperature changes to individual components or small sets of components, the tools and methods allow greater control over the analysis of interactions within a board. This may allow clearer understanding of the effects of temperature on circuit component behavior. The tools and analysis advances analysis such as failure analysis and design testing.

Abstract: Tools and methods for creating isolated or localized temperature changes on components in an electric circuit. By isolating temperature changes to individual components or small sets of components, the tools and methods allow greater control over the analysis of interactions within a board. This may allow clearer understanding of the effects of temperature on circuit component behavior. The tools and analysis advances analysis such as failure analysis and design testing.

Abstract: The invention provides a canal hearing device and method in which the device is implemented with a mode of operation that provides acoustic transparency as well as a power-saving function, particularly useful to permit the user to wear the device in the ear canal during periods of sleep or inactivity without substantial loss of normal unaided response. The transparent mode has an in-situ acoustic transfer function that compensates for the insertion loss caused by the presence of a hearing device in the ear canal. While the device is in this transparent mode, its acoustic transfer function gives the user a perception of unaided hearing, as though the device were removed, when it is actually being worn continuously in the ear canal. Current drain of the device is significantly reduced as the transparent mode serves to shut off or reduce bias currents of at least one circuit element within the device circuitry.

Abstract: A defibrillator for providing a constant low pulsed current to a patient's heart has a high voltage capacitor for storing electrical energy. An inductor connected to the capacitor smooths out the discharge curve and produces a low current low frequency defibrillator pulse supplied to a patient's heart. The pulse is usually biphasic.

Abstract: A method of treating patients suffering from refractory hypertension includes identifying a patient suffering from the disorder and applying a stimulating electrical signal to the patient's vagus nerve predetermined to modulate the electrical activity of the nerve and to alleviate the hypertension. The step of applying the stimulation may be performed manually by the patient, or automatically following detection of the hypertension by sensing the patient's blood pressure, or, preferably by continuous or periodic application without use of a sensor. The stimulating signal is a pulse waveform with programmable signal parameter values including pulse width, output current, frequency, on time and off time.

Abstract: A method of treating a patient in coma is performed by placing an electrode in juxtaposition with a preselected cranial nerve of the patient for electrical stimulation of the nerve, applying an electrical pulse waveform to the electrode to stimulate the cranial nerve, and adjusting electrical parameters of the pulse waveform to modulate electrical activity of the nerve in an effort to rouse the patient from the coma. The patient's response to the treatment is monitored and assessed by the attending physician according to Glasgow coma scale. The preferred cranial nerve is the vagus nerve, and the stimulation is performed either for acute treatment by positioning an esophageal electrode in the patient for stimulating a region of the vagus nerve in the neck, or for longer term treatment by implanting a nerve electrode on the vagus nerve.

Abstract: Apparatus for treating patients with motility disorders applies a modulating signal to the patient's vagus nerve to stimulate or inhibit neural impulses and produce excitatory or inhibitory neurotransmitter release by the vagus nerve according to the specific nature of the motility disorder. The apparatus includes a neurostimulator which can be activated to generate an electrical output signal. The neurostimulator is responsive to the sensing of a selected event having occurred which is indicative of the need for treatment of the motility disorder, and includes an activation element which responds to sensing of that event to activate the neurostimulator, and a lead with an electrode array to apply the electrical output signal as the modulating signal to the patient's vagus nerve. Certain parameters of the output signal are programmable, and the neurostimulator can be calibrated according to the specific patient and the specific motility disorder being treated.

Abstract: An electrode assembly of a lead to be implanted on a patient's nerve includes a flexible electrically insulative carrier of helical configuration, a flexible ribbon electrode secured to the underside of at least a segment of the helical configuration carrier, an elongate conductor for electrical connection to the ribbon electrode, and a flexible conducting spacer electrically connected to the ribbon electrode and to the elongate conductor for separating the latter from the helical configuration while maintaining electrical connection between the two at the distal end of the elongate conductor. The distal end of the conductor projects directly and tangentially from a curved portion of the spacer in a direction substantially parallel to the longitudinal axis of the helical configuration.

Abstract: Improvements are disclosed in apparatus and techniques for activating an implantable medical device, such as a neurostimulator adapted to treat and control a disorder of a patient where the disorder is susceptible to relief in response to predetermined modulation of the electrical activity of a selected nerve or group of nerves of the patient. The neurostimulator includes a stimulus generator responsive, when activated, to generate a programmable electrical waveform, and an electrode array electrically connected to the stimulus generator for delivering the waveform to a selected nerve of the patient, such as the vagus nerve. The neurostimulator is also adapted to be programmed to provide the waveform with parameter values selected to stimulate the selected nerve to produce the predetermined modulation of the nerve's electrical activity.

Abstract: A method of treating patients with compulsive eating disorders includes the steps of detecting a preselected event indicative of an imminent need for treatment of the specific eating disorder of interest, and responding to the detected occurrence of the preselected event by applying a predetermined stimulating signal to the patient's vagus nerve appropriate to alleviate the effect of the eating disorder of interest. For example, the preselected event may be a specified level of food consumption by the patient within a set interval of time, or the commencement of a customary mealtime according to the patient's circadian cycle, or the passage of each of a sequence of preset intervals of time, or the patient's own recognition of the need for treatment by voluntarily initiating the application of the stimulating signal to the vagus nerve. In cases in which the disorder is compulsive eating to excess, the stimulating signal is predetermined to produce a sensation of satiety in the patient.

Abstract: An implantable medical device is provided with a removable dummy load across its connector output terminals to allow the device to be tested without removal from the sterile disposable package in which it is shipped and stored. The dummy load is confined with the device entirely within the sterile package to simulate the electrical impedance across the output terminals when the device is implanted in a patient and connected to an electrical lead for tissue stimulation. Testing is performed using a conventional external programmer normally provided for programming and monitoring output functions and parameters of the device. The programmer communicates by telemetry with the device confined within the package, to test selected functions and parameters. The dummy load has posts adapted to mate with the receptacles of the electrical connector of the device, and to be secured mechanically and electrically in the receptacles by set screws.

Abstract: Apparatus is disclosed for stabilizing the value of a parameter of the output pulses of a tissue stimulator, such as the magnitude of the current or the charge delivered in each output pulse to excite the cell membranes of the tissue to be stimulated. The apparatus measures the value of this parameter against target limits, and if either limit is exceeded, adjusts the value of a second parameter of the output pulses, such as voltage level or pulse width, to stabilize the value of the first parameter. The value of the first parameter may be measured by sampling thereof at a rate considerably less than the frequency of the output pulses, and the value of the second parameter then adjusted to bring the value of the first parameter within the target limits. Both current and charge stabilization modes of the pulse generating stimulator for efficient excitation of cell membranes of the selected tissue are described.

Abstract: Method and apparatus for treating and controlling migraine by selectively applying a predetermined electrical signal to the patient's vagus nerve for stimulation thereof to alleviate the migraine attack. The signal is a pulse waveform having parameters programmed to desynchronize the patient's EEG if paroxysmal activity is detected in the EEG, or to synchronize the EEG if low voltage fast wave activity is detected. Alternatively, the application of the stimulating signal to the vagus nerve may be initiated manually by the patient upon recognition of the onset of a migraine attack. The neurostimulator device implanted in the patient to generate the appropriate signal has a power down circuit to conserve battery power between migraine episodes.

Abstract: A nerve electrode array includes one or more Y-shaped carriers in which the three legs of the Y are curled about a common axis with the lower leg of the Y oppositely directed relative to the other two so that the legs will encircle a nerve substantially sharing the common axis, and a flexible electrode secured to the underside of at least one of the legs.

Abstract: In conjunction with a medical device for stimulating the vagus nerve of a patient to modulate the electrical activity thereof as part of a prescribed therapy, apparatus is provided to selectively suppress the stimulation while the patient is speaking, to avoid undesirable modulation of the voice. The suppression apparatus includes a speech sensor and discriminator, to detect speech by the patient while avoiding false detection attributable to sounds other than speech. The suppression of nerve stimulation is ceased after a preset time interval regardless of continued detection of speech, to assure that beneficial therapy is not unduly inhibited in favor of mere cosmetic considerations or in the presence of prolonged false detections.

Abstract: A method of treating patients with compulsive eating disorders includes the steps of detecting a preselected event indicative of an imminent need for treatment of the specific eating disorder of interest, and responding to the detected occurrence of the preselected event by applying a predetermined stimulating signal to the patient's vagus nerve appropriate to alleviate the effect of the eating disorder of interest. For example, the preselected event may be a specified level of food consumption by the patient within a set interval of time, or the commencement of a customary mealtime according to the patient's circadian cycle, or the passage of each of a sequence of preset intervals of time, or the patient's own recognition of the need for treatment by voluntarily initiating the application of the stimulating signal to the vagus nerve. In cases in which the disorder is compulsive eating to excess, the stimulating signal is predetermined to produce a sensation of satiety in the patient.

Abstract: A body function assistance device, capable of analyzing changing but cyclic physiologic needs of a patient and generating a response based on the analysis. A microprocessor in the body function assistance device controls the response of the device to various external events and internal timer events. The microprocessor recognizes variations in patterns of recurrent events and adjusts the output of the body function assistasnce device in response to the detected variations. In a particular embodiment, an implantable cardiac pacer is responsive to a circadian wake-sleep cycle.

Abstract: A state machine for automatic gain control of sensing functions in an implantale cardiac stimulator. The state controls sensing levels based on present sensed conditions and on the prior state of the heart. Different rates of adjustment are selected under varying conditions so that the gain level for sense amplifiers can be adjusted without significant overshoot. The state machine comprises a set of four conditions or states together with interconnections or logical paths from one state to another. The rate of adjustment of sense amplifier gain is based on the path traversed in the state machine so that different effective time constants for the control function may be used for different conditions.

Abstract: A series of test signals are generated by a microprocessor of a pacemaker to determine whether a bipolar or unipolar lead is attached to an implanted cardiac pacemaker restricting programming of said pacemaker to only an unipolar pacing mode unless the presence of an operational bipolar lead is detected. Detection is accomplished by generating a series of low frequency high impedance pulses, applying them to lead contacts and sensing a return signal. If a return signal is detected, then that indicates either a unipolar lead is connected to the pacemaker or that the ring conductor of a bipolar lead is open and bipolar pacing must be inhibited.

Abstract: A body function assistance device, capable of analyzing changing but cyclic physiologic needs of a patient and generating a response based on the analysis. A microprocessor in the body function assistance device controls the response of the device to various external events and internal timer events. The microprocessor recognized variations in patterns of recurrent events and adjusts the output of the body function assistance device in response to the detected variations. In a particular embodiment, an implantable cardiac pacer is responsive to a circadian wake-sleep cycle.