The somatosensory evoked potentials have been considered as one of the objective prognostic factors of the hemiplegic patients. Many studies were done about the relationships of the median nerve somatosensory evoked potential with recovery of the upper extremities. But the recovery of lower extremities is thought to be different from that of upper extremities, so somatosensory evoked potential of lower extremities, for example, posterior tibial nerve somatosensory evoked potentials may be more suitable for prediction of recovery of lower extremities in the hemiplegic patients. However, studies about posterior tibial nerve evoked potentials as a prognostic factor in the hemiplegic patients are a few.

We studied median nerve and posterior tibial nerve somatosensory evoked potentials of the 72 hemiplegic patients, and follow up studies were done in 21 of them with interval of average 15 months. We compared correlations of the above two kinds of somatosensory evoked potentials with physical findings and their prognostic significance.

In result, sensory recovery was accompanied with improvement of somatosensory evoked potentials, but motor recovery was present in all patients with or without improvement of somatosensory evoked potentials. Better results in the somatosensory evoked potentials were accompanied with significantly shorter length of hospital stay, but modified Barthel Index score was not different significantly except the score of lower extremities. We suggest that both median nerve and posterior tibial nerve somatosensory evoked potentials are considered to be the prognostic factors of the hemiplegic patients because they represent mainly sensory recovery and both of them are needed for more complete prediction of the prognosis.