The differential contributions of posttraumatic amnesia duration and time since injury in prediction of functional outcomes following moderate-to-severe traumatic brain injury

OBJECTIVE: To examine the relative contributions of preinjury, injury severity, and acute postinjury variables in predicting outcomes at 1 year following moderate-severe traumatic brain injury (TBI). DESIGN: Secondary analysis of a prospective longitudinal cohort study. SETTING: Four Veterans Affairs Medical Center acute inpatient rehabilitation programs. PARTICIPANTS: Active duty military or veterans with a nonpenetrating moderate-to-severe TBI. MAIN OUTCOME MEASURES: Independent living status (N = 280) and work status (N = 248) at one year postinjury. RESULTS: Preinjury characteristics as a group accounted for the largest amount of variance in independent living status at 1 year; however, posttraumatic amnesia (PTA) uniquely explained the largest amount of variance (8.8%). Those with less than 60 days PTA were 9 times more likely to be independent; those with less than 30 days PTA were 3 times more likely to be independent. In contrast, acute postinjury characteristics accounted for the largest amount of variance in work status, with time to rehabilitation explaining the most unique variance (10.4%). Those with less than 48 days time to rehabilitation were 2.4 times more likely to be productive. CONCLUSIONS: This study highlights the differential contribution of variables in the prediction of 2 specific functional outcomes in a military sample, adding to our current body of knowledge to assist clinicians, patients and their families following TBI.