MONITORING SEVERE HEAD-INJURY - A COMPARISON OF EEG AND SOMATOSENSORY-EVOKED POTENTIALS

We report on our experience with long-term monitoring of the EEG power spectrum and somatosensory evoked potentials (SSEPs) in 103 patients with severe closed head injury (Glasgow Coma Scale - GCS less than or equal to 8). Patients were monitored for an average of 5 days post inj ury and monitoring was terminated when they died, regained consciousne ss or their intracranial physiologic parameters (primarily intracrania l pressure - ICP) were stable for 2-3 days, Patients were treated acco rding to a standard protocol that included mechanical ventilation, sed ation, and neuromuscular blockade, At 7 of 9 twelve hour time interval s post injury, SSEPs were significantly (p < .05) different between ou tcome groups using the Glasgow Outcome Score collapsed to 3 categories . The percent slow (delta) activity in the EEG was not significantly d ifferent between outcome groups at any time point, post injury. The to tal power in the EEG power spectrum differed only at the last time epo ch post injury (108 hr.). Based on the superior prognostic capabilitie s of the SSEP, we routinely base critical management decisions on SSEP values. We have not been able to rely on EEG parameters for these sam e decisions due to the lack of clear distinction between good and poor prognosis groups based on common EEG parameters.