Automatic activation of a neurostimulator device using a detection algorithm based on cardiac activity

Abstract

A device and method of controlling seizures in an epileptic patient, in which the device is implanted in the patient for selective activation to generate an electrical waveform constituting a pre-programmed therapy regimen for application to the patient's vagus nerve to modulate the electrical activity thereof in a manner to inhibit, abort, or reduce the severity and duration of the seizure. The device is activated to generate the waveform upon detecting a time rate of change in the patient's heart rate relative to a predetermined threshold time rate of change which is sufficiently abrupt and of sufficient magnitude to be inconsistent with normal physical activity, as being indicative of an imminent epileptic seizure. Sustained cardiac activity at the highest heart rate detected in the change in heart rate is used as a confirmation of imminent seizure. The electrical waveform is generated a burst of pulses, with a minimum time interval between consecutive pulse bursts selected to avoid overstimulation of the nerve. Cardiac activity of the patient is detected using electrodes which include the conductive housing for the device and a stimulating electrode to be mounted on the nerve for large signal detection, or which are integral with the device housing itself so that no electrical leads are required to be implanted for such detection and the electrodes are arranged to detect the cardiac activity with a sensitivity that is substantially independent of orientation of the device as implanted in the patient.

Dependencies are inferred from the claim text.