Somatosensory evoked potentials are the electrical responses of the Central Nervous System (CNS) to stimulation of a peripheral nerve.
SSEPs are induced by electrically stimulating peripheral nerves and are recorded using epidural or scalp electrodes.
The posterior tibial or common peroneal nerves are most commonly used. Adhesive electrodes (pads) are used for stimulation. Recording electrodes are placed directly in the epidural space or on the scalp and on the cervical spine. Adequate filtering and shielding must be used to remove or reduce all mains, electrical and neurophysiological interference.
Amplitude, latencies and shape of the responses are monitored and recorded. Establishing a stable baseline recording prior to any major surgical activities is very important.
Changes from the baseline responses are the most important indicators of neurological dysfunction.