Assessing brain function in post-traumatic coma by means of bit-mapped SEPs, BAEPs, CT, SPET and clinical scores. Prognostic implications.

Sixty-eight severely head injured comatose patients were studied. Bit-colour-mapped SEPs to median nerve stimulation, BAEPs, CT and SPET regional values and ICP were assessed in relation to clinical information in evaluating cerebral function. All these variables were related to a 1-year outcome. Statistical tests confirmed the higher predictive reliability of both neurophysiological and perfusive (SPET) functional parameters compared to CT structural findings. Generally, SEPs appeared to be more reliable in predicting outcome than BAEPs. Modifications of frontal components could occur independently of post-central ones, being closely related to underlying cerebral lesions. The parameter showing the greatest correlation with outcome in the first recording session was the P25 latency, whereas this prognostic role was mainly assumed by the amplitude value of the frontal N30-P45 complex in a second recording session carried out during the third week following head trauma.