Short- and long-term prognostic value of the electroencephalogram in children with severe head injury.

To determine the prognostic value of the EEG in severely head-injured children, 24 patients were studied for 8-36 months. During coma, 4 EEG patterns were found: borderline, sleep-like, changeable and slow monotonous (SM). For the short-term prognosis, we conclude that the SM pattern (12/24 patients) indicates a bad prognosis because it was associated with a longer coma and awakening period than that of other EEG patterns and because it was observed in the 3 patients who died from brain injury. In contrast, we describe a 'prewake' pattern (11/22 survivors) which, when it occurs, always announces the onset of a complete awakening. For the long-term prognosis, only 50% of the survivors who had an SM pattern during coma have as good an intellectual and motor outcome as the survivors who displayed other EEG patterns. No other EEG features recorded during coma have short- or long-term prognostic significance.