Abstract: A pacemaker is provided having an improved circuit for obtaining a measure of battery end-of-life. The EOL detector includes an input stage with a current mirror output providing a current which is proportional to the current being consumed by the pacemaker circuitry, and thus being expended by the battery. The proportional current is directed to charge a capacitor, which is periodically discharged at a constant current, following which the battery goes through repeated cycles of charging and discharging. A measuring circuit measures the time of capacitor discharge, thereby providing a measure of battery energy discharge during the interval that the capacitor was charging. The interval counts are accumulated to provide an overall count representative of battery expenditure, and thus of pacemaker EOL.

Abstract: A system and method are provided for accurate determination of various tremors and movements derived from Parkinson's Disease and other causes. Movement signals are generated by an accelerometer, the movement signals being analyzed to determine whether they are in a predetermined frequency range, and when there occurs an uninterrupted series of such movement signals that are within the frequency range. By determining when these two criteria are met, tremor signals are reliably discriminated from other activity signals. The system includes circuitry for collecting and storing data concerning the timing of tremor occurrences, the timing of other activity occurrences, and amplitude data concerning tremor occurrences.