Posttraumatic Amnesia as a predictor of outcome after severe closed head injury. Prospective assessment

To identify the demographic and clinical variables related to the duration of posttraumatic amnesia after severe closed head injury; to evaluate the usefulness of posttraumatic amnesia duration in predicting outcome at the time of hospital discharge and at 6 months after injury.

Four clinical centers located in primary care hospitals.

Three hundred fourteen severely injured subjects aged 16 years or older who did not have trauma as a result of a penetrating injury and came out of coma before hospital discharge.

Approximately half of the subjects were administered phenytoin sodium for some period after termination of coma; 17% were administered dexamethasone and 41% morphine sulfate.

Galveston Orientation and Amnesia Test scores defined the duration of posttraumatic amnesia. The Glasgow Outcome Scale was used to grade outcome at the time of hospital discharge and at 6 months.

Older age, low initial Glasgow Coma Scale score, nonreactive pupil(s), coma duration, and use of phenytoin were associated with a longer duration of posttraumatic amnesia. Poor pupillary response, time in coma, and duration of posttraumatic amnesia and use of phenytoin was predictive of the 6-month outcome.

The results support the prognostic usefulness of prospectively measuring duration of posttraumatic amnesia after termination of coma. Pending replication, our findings suggest that posttraumatic amnesia duration may be a useful surrogate outcome measure for clinical trials involving interventions for acute head injury.