[Central motor conduction time in multiple sclerosis: an comparison of visual and somatosensory evoked potentials in relation to the type of disease course].

The central motor conduction time (CMCT) was measured by electrical transcranial and spinal stimulation in 70 consecutively admitted patients with definite multiple sclerosis and 26 normal volunteers. The results of the patientgroup were compared with visual and somatosensory (median and tibial nerve) evoked potentials. The mean CMCT of the volunteers was 5.4 ms versus 11.1 ms in the patient group. In 55 of the 70 patients (79%) the CMCT was delayed (p less than 0.0001). VEP showed pathologic results in 67%, SEP of tibial nerve in 51%, SEP of median nerve in 41% of the patients. In 10 of the 70 cases (15%) only CMCT was pathologic. Especially in the first attack of the disease the CMCT (79% pathologic results) was superior in comparison to the evoked potentials (VEP and SEP together 43% pathologic findings). In our cases without clinical evidence of a pyramidal tract lesion a subclinical affection of this pathway could be determined in 69% by a pathologic CMCT. We regard this method therefore as a valuable tool in the early diagnosis of multiple sclerosis.