Clinical and electroencephalographic correlates of acute encephalopathy.

The term encephalopathy encompasses a wide variety of syndromes caused by a large number of different toxic, metabolic, and degenerative derangements. Despite advances in intensive medical care and new diagnostic procedures, encephalopathy remains a frequent and underrecognized critical medical condition with high morbidity and mortality. Electroencephalography (EEG) enables rapid bedside electrophysiological measurements of brain dysfunction and complements clinical and neuroimaging assessment of encephalopathic patients. Both progressive slowing of EEG background activity with increasing cerebral compromise and decreased EEG reactivity to external stimuli provide important diagnostic and prognostic information. The aim of this review was to provide an overview of the diagnostic and prognostic value of EEG in encephalopathic patients.