A Clinico-Physiological Study of Visually Evoked Potential (VEP) and Somatosensory Evoked Potential (SEP) in So-Called Vegetative State and Delta Coma

Abstract

We reported the results of visually evoked potential (VEP) and somatosensory evoked potential (SEP) examinations in 10 patients in the vegetative state and 20 patients in the coma state following acute serious brain damages. Variable behaviors of average VEP and SEP in vegetative state were divided into four groups, Group I, had a marked suppression or absence of VEP and SEP simultaniously (20%). Group II had a suppression or absence of VEP with a near-normal SEP (20%). Group III had a suppression or absence of SEP with a near-normal VEP (30%). Group IV had a near-normal VEP and SEP respectively (30%). On the other hand, all of 20 patients with acute disturbed consiousness of delta coma had a marked suppression or absence of each component of average VEP and SEP. Concerning the prognoses of cases of acute serious brain damages, those who had recovered from VEP and SEP within three or four weeks after the serious brain damage, did not fall into the vegetative state. Even when patients had fallen into the vegetative state for about four months, in cases where recoveries of VEP and SEP were observed antecedent to those of EEG, they managed to be free from falling into a permanent vegetative state. Based on these results, it is concluded that clinical study of VEP and SEP in the vegetative state or the acute coma state could be a useful diagnostic aid to predict the prognoses of these vegetative patients. © 1975, The Japan Neurosurgical Society. All rights reserved.