Evoked Potentials

Evoked potentials (EPs) are the electrical signals produced by the nervous system in response to an external stimulus. They are used for clinical diagnostic testing and for intraoperative monitoring. Visual, auditory, and short-latency or 'brainstem' auditory EPs can be used to assess sensory organs (eyes and ears) and afferent sensory pathways. Sensory EP components can be divided into latency categories, which are differentially affected by attention, cognitive tasks, and anesthesia. Motor EPs can be recorded from muscles or from the spinal cord following transcranial or direct stimulation of the brain; they are used to assess central motor pathways.