Closed head injuries (CHI; nonpenetrating head injury produced by sudden acceleration/deceleration, as in motor vehicle crashes) often cause memory impairments. Both retrograde amnesia (RA) and difficulty in learning and retaining new information (anterograde amnesia) can result from CHI. Post-traumatic amnesia (PTA) refers to the symptom complex of anterograde amnesia, disorientation, and attentional disturbance during the initial stage of recovery, but dissociations can occur in some patients. Even after the abatement of PTA and RA, half of severe CHI victims suffer from residual impairments. (Russell, 1971).

The pathophysiologic contribution to residual memory disturbance is difficult to isolate because of the heterogeneity of many injuries associated with CHI, including primary and secondary causes of brain damage and confounding comorbidities such as alcohol abuse. However, several pathophysiologic features of CHI, including the Glasgow Coma Scale score (GCS) and duration of coma have been linked to memory deficit. Proximity of...