IS EEC USEFUL IN ASSESSING PATIENTS WITH ACUTE ENCEPHALITIS TREATED WITH ACYCLOVIR

EEG has been used widely in diagnosing encephalitis. as it demonstrate s rather typical abnormalities, especially in herpes simplex virus enc ephalitis (HSVE). We analysed 204 EEG recordings from 98 consecutive a cyclovir-treated patients with acute encephalitis between 1984 and 199 4. Periodic complexes (PC) in the acute phase predicted poor outcome ( Kendall tau 0.40, P < 0.001). However, unlike in many other diseases, e.g. stroke and intracerebral haemorrhage, the diffuse slowing of the background activity at acute phase did not predict outcome (Kendall ta u -0.6, P = 0.35). At follow-up, the emergence of diffuse slow backgro und activity was significantly associated with a less favourable outco me (Kendall tau 0.33, P = 0.0016). Among clinical variables, only epil eptic seizures early during the course of the disease correlated signi ficantly with outcome. EEG does have Value as a prognostic indicator i n acute encephalitides, but it seems that diffuse slowing of backgroun d activity or irritative features acutely are not as important as prev iously thought, based on the experiences of the pre-acyclovir era. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.