
A somatosensory evoked potential (SSEP) is an evoked potential caused by a physical stimulus (usually a small electric pulse). Electrodes positioned over particular areas of the body record responses of the SSEP, these are then observed as a reading on an electroencephalogram (EEG). A SSEP can most commonly involve stimulation of the median nerve at the wrist, or the posterior tibial nerve at the ankle. This investigation therefore tests the pathway of the sensory nerves to the sensory areas of the brain, even though the stimuli are non-physiological.