[The EEG in necrotizing herpes encephalitis (author's transl)].

34 EEG records of 9 patients with verified necrotizing-herpes-encephalitis permit the following statements concerning the electroencephalographic findings. 1. The EEG is always severely affected in the acute stage. This is characterized by a progressive slowing and disorganization, almost constantly coexistent with focal signs or pronounced asymmetries. 2. The preferential site in the temporo-insular, hippocampal and orbitofrontal regions of the pathological process is almost invariably reflected by the uni- or bilateral fronto-temporal local slow-wave abnormality. Even bilateral processes may show asymmetries, which correspond to the different expansion of the process in the hemispheres. 3. Periodic complexes, if present differ from those seen in Creutzfeldt-Jakob disease and in subacute sclerosing panencephalitis. They are highly suggestive of the diagnosis of herpes encephalitis but do not indicate always a poor prognosis. 4. Local slow wave abnormality may be followed by local flattening indicating a necrosis of large cortical areas. 5. Epileptiform discharges present in only 7 of the 34 records were always focal or lateralized. 6. In a case followed up to 46 months the EEG became temporarily normalized although severe neurologic deficits were present at the same time.