evoked potential (EP) /ivōkt″/ [L, evocare, to call forth, potentia, power] , an electrical response in the brainstem or cerebral cortex that is elicited by a specific stimulus. The stimulus may affect the visual, auditory, or somatosensory pathway, producing a characteristic brain wave pattern. The activity and function of the system may be monitored during surgery while the patient is unconscious. The surgeon is thus able to prevent damage to the nerves during operative procedures. Evoked potentials are also used to diagnose multiple sclerosis and various disorders of hearing and of sight. Kinds include brainstem auditory evoked response, somatosensory evoked potential, visual-evoked potential. See also brain electric activity map.
