PREDICTION OF OUTCOME IN SEVERE HEAD-INJURY BASED ON RECOGNITION OF SLEEP-RELATED ACTIVITY IN THE POLYGRAPHIC ELECTROENCEPHALOGRAM

This study shows that the continuing presence of activity similar to n ormal sleep in the EEG in conjunction with the EEG polygraph (EEGP) ca n be used to determine the severity of brain damage after head injury. Recordings were taken within seven days of head injury from 154 unsel ected patients after resuscitation and emergency surgery. Sixteen pati ents with ongoing seizures were excluded. In the remaining 138 patient s the presence of activity in the EEG, EEGP, or both, which can also b e recognised in normal alertness and sleep, was noted. Particular atte ntion was paid to the presence or absence of arousal related phasic ac tivity involving EEG, motor, and autonomic changes. The traces were al located to one of five groups: group 1, wakeful traces with normal alp ha in at least one hemisphere; group 2, sleep-like traces with K compl exes responsive to stimulation; group 3, traces with phasic activity r elated to abnormal spontaneous arousal including EEG changes; group 4, traces with abnormal spontaneous arousal activity without EEG changes ; group 5, traces with no spontaneous arousal activity. The mean follo w up was 21.5 months. Groups 2 and 3 were significantly associated wit h a good outcome and group 5 with death or a vegetative state. Compari son between the EEG/EEGP findings and the Glasgow coma scale at the ti me of the recording showed the EEG/EEGP to be the better predictor of outcome, particularly for individual patients.