1. An implantable medical device system for implantation in a patient, the system comprising: a biocompatible housing adapted to be implanted in a patient; a brain monitoring element adapted to sense activity in a brain of the patient and generate a brain signal; a respiratory monitoring element, the respiratory monitoring element adapted to sense respiratory activity and generate a respiratory signal, the respiratory monitoring element comprising a sensor stub; a therapy module at least partially supported by the housing, the therapy module adapted to deliver a therapeutic output to the brain of the patient when a respiratory event is detected in the respiratory signal; and a processor at least partially supported by the housing, the processor configured to receive the respiratory signal from the respiratory monitoring element and detect a respiratory event in the respiratory signal, activate the therapy module to deliver the therapeutic output to the brain based on detecting a respiratory event in the respiratory signal; receive the brain signal from the brain monitoring element and detect a neurological event in the brain signal; determine whether a neurological event has been detected in the brain signal within a specified period of time after detection of the respiratory event; and change the therapeutic output delivered by the therapy module based on the sensed brain activity that occurs following a detected respiratory event.