Devices and methods for sensing physiological signals during stimulation therapy

Abstract

Devices and methods provide for the sensing of physiological signals during stimulation therapy by preventing stimulation waveform artifacts from being passed through to the amplification of the sensed physiological signal. Thus, the amplifiers are not adversely affected by the stimulation waveform and can provide for successful sensing of physiological signals between stimulation waveform pulses. A blanking switch may be used to blank the stimulation waveform artifacts where the blanking switch is operated in a manner synchronized with the stimulation waveform so that conduction in the sensing path is blocked during the stimulation pulse as well as during other troublesome artifacts such as a peak of a recharge pulse. A limiter may be used to limit the amplitude of the sensed signal, and hence the stimulation artifacts, that are passed to the amplifier without any synchronization of the limiter to the stimulation waveform.

1 - 21 . (canceled) 
     
     
         22 . A method of sensing physiological signals while providing stimulation therapy, comprising:
 while a stimulation signal having a stimulation phase and a recharge phase is being output from a first electrode at a stimulation site, sensing a physiological signal at a second electrode in proximity to the stimulation site; and   while sensing the physiological signal, limiting an amplitude of the sensed signal.   
     
     
         23 . A device for sensing a physiological signal while stimulation therapy is being provided, comprising:
 a sensing electrode;   a signal limiter;   an electrically conductive pathway connected between the sensing electrode and the signal limiter; and   a sensing amplifier electrically coupled to the signal limiter.