Spinal and cortical evoked potentials in multiple sclerosis.

Spinal and cortical sensory evoked potentials following stimulation of median and lateral popliteal nerves were performed in patients with definite multiple sclerosis in order to assess the usefulness of these procedures in the diagnosis and subsequent evaluation of multiple sclerosis. Abnormal SEP's were detected in 69% of patients. Abnormal spinal evoked potentials following median nerve stimulation were detected in 21 of 40 (52%) patients, and in a further 7 patients abnormalities were detected in cortical SEP's or in spinal SEP's when stimulating the lateral popliteal nerves. Close correlation was observed between the frequency of abnormal sensory signs or symptoms and the presence of electrophysiological abnormalities. When progress studies were performed a gradual deterioration was demonstrated in one or more SEP's of 12 of 24 patients.