Short-latency somatosensory evoked potentials (SSEPs) of the tibial nerves in spinal cord injuries.

Stimulations of the tibial nerves of 76 spinal cord injured patients revealed short-latency somatosensory evoked potentials (SSEPs) especially P37 recorded from the scalp. The SSEPs findings can be classified by degrees of impairment into 5 different types as follows: Type 1: Absence of P37. This was found in all patients with complete cord lesions as well as patients with loss of joint sense. Type 2: Decreased amplitude and prolonged latency. This was elicited in patients with moderate to severe central cord lesions. Type 3: Prolonged latency only. Type 4: Decreased amplitude only. Type 5: Normal P37, which was mostly seen in patients with mild central cord lesion. The study demonstrated that SSEPs of the tibial nerves are related to joint sense and seem to relate to the extent of cord damage, especially of central cord and complete cord lesions. It can be done as early as during the first week post injury, particularly in an uncooperative patient suspected of having spinal cord injury, in which case the clinical assessment may be difficult and unreliable.