Median nerve and posterior tibial nerve somatosensory evoked potentials in the non-affected hemisphere: a prospective one-year follow-up study in patients with supratentorial cerebral infarction.

Somatosensory potentials in the non-affected hemisphere evoked by simulation of both the median nerve (median nerve SEPs) and the posterior tibial nerve (tibial nerve SEPs) were studied in 40 patients with supratentorial nonhaemorrhagic cerebral infarction three times during a one-year follow-up period. The EP-N20 interpeak latencies (IPLs) of the median nerve SEPs were on average longer in the patient group than in the control group (especially in patients with evidence of mass displacements in the cerebral computed tomography), whereas no significant differences were observed in the amplitudes of the median nerve SEPs. The P57-N75 amplitudes of the tibial nerve SEPs were on average lower in the patient group than in the control group. During the follow-up period the peak latencies and the P40-N75 IPLs of the tibial nerve SEPs increased and the amplitudes of the tibial nerve SEPs diminished.