Duration of Unconsciousness

Duration of unconsciousness is another measure of severity and has the advantage of longer obser­vation than GCS. It is also easier to recognize than the duration of amnesia in children and is more easily determined in retrospective chart reviews.

Although most outcome studies have correlated outcome with only one index of brain injury sever­ity (62,63), McDonald and colleagues (57) compared 10 measures. In their report, the number of days to reach age-adjusted 75% performance on the COAT, the number of days to GCS 15, and the initial GCS scores were most predictive of outcome across all neurobe- havioral and functional measures when measured early and at 1 year post injury. The intercorrelations of these brain injury indexes were also quite high. In general, these indexes could be used interchangeably and a single measure of severity predicted most out­comes almost as well as multiple measures. Severity ratings as determined by these alternative criteria are summarized in Table 10.1.

In summary, it is important to use these tools and correlate them with clinical findings to make an assessment of severity of injury and therefore possible long-term outcome. Although useful, these assessment tools do have limitations in determining outcome, and a clinician’s clinical impression is also important.