[Role of multimodal evoked potentials in evaluations of persistent vegetative state of nontraumatic origin]

Persistent vegetative state (PVS) is a kind of release from coma, manifesting by absence of any signs of cognitive activity. Progress in reanimatology leads to an increase in the number of patients with PVS, thus creating a new medical and social problem. Study of atraumatic PVS acquires special importance because of a drastic increase in its incidence, necessitating definition of criteria of this state formation and its prognostic signs. Multimodal evoked potentials (MEP) now play an important role in diagnosis and prediction of PVS. The impact of acoustic stem (ASEP), visual (VEP), somatosensory (SSEP), and cognitive (CEP) evoked potentials is analyzed and early diagnostic and prognostic neurophysiological criteria are defined. Results of dynamic examinations of 23 patients (9 men and 14 women) aged 10-67 years with atraumatic PVS are presented. According to neurophysiological data, PVS in the majority of patients is characterized by absence of cognitive responses to a significant stimulus (wave P300) during examinations of CEP and of cortical response during examination of SSEP. VEP and long latent acoustic evoked potentials are as rule intact in atraumatic PVS. According to ASEP, stem functions were intact or slightly changed in the examined patients with PVS. Prognostically unfavorable and relatively favorable signs in the time course of MEP are defined.