A medical device system includes a housing, a therapy module and a processor at least partially supported by the housing, and a cardiac monitoring element coupled to the processor, the cardiac monitoring element comprising a stub sensor. The processor is configured to activate the therapy module upon detection of a cardiac event in a cardiac signal. In some embodiments, the system may further comprise a brain monitoring element coupled to the processor. In some embodiments, the processor may be configured to monitor a brain signal and change the therapeutic output based upon the brain signal.