The determinants and correlates of outcome following traumatic brain injury, a prospective study

by Dawson, Deirdre R.

The determinants and correlates of outcome at one (Time 1) and four (Time 2) years posttraumatic brain injury (TBI) were investigated prospectively in patients (n=92) recruited consecutivefy following admission to Canada's largest regional trauma centre. Friends and family members sewed as control subjects. Sixty-three percent of subjects who completed baseline testing completed follow-up interviews at Time 1. Of these, 72% completed neuropsychological testing. Fifty-three percent of subjects completed follow-up interviews and neuropsychological testing at Time 2. Demographic, injury-severity, acute imaging findings, and acute neuropsychologicalfunction (attention, orientation, memory) were investigated as determinants of outcome. Neuropsychological status (attention, memory, executive function) at Time 1 and 2, and psychological status (depression, locus of control, coping style) and social support at Time 2 were investigated as correlates of outcome. Outcomes evaluated at both time points included psychosocial outcome, and a measure of return to productivity (RTP) (work andlor school). At Time 2, quaiity of life (QOL) data were also reported. At both time points, TBI subjects reported considerable psychosocial distress relative to controls. At Time 1, 66% of TBI subjects had returned to productive activity, at Time 2, this increased to 78%. Determinants of outcome at Time 1 showed baseline memory status to be significantly associated with RTP (p50.0007). Injury severity and measures of acute neuropsychological status showed a trend to be associated with psychosocial outcome and RTP (ps0.05). Determinants of outcome at Time 2 again showed acute memory status to be associated with RTP (pi0.003) and other measures of acute neuropsychological status to be associated with psychosocial status, RTP, and QOL at ps0.05. Psychological variables and social support were strongly correlated with psychosocial status, RTP, and QOL at Time 2. When included in hierarchical regression analyses with acute neuropsychologicaI variables, they accounted for substantially more variance in each outcome. A small proportion of the neuropsychologicaltest scores (measuring general slowing, memory and executive function) correlated with outcome at both time points. These data suggest that the influence of brain pathology on outcome is attenuated over time. Long-term outcome is explained by many factors: psychological factors and social support are particularly important. I would like to acknowledge and thank the people who made the completion of this thesis possible; ... the patients interviewedfor this study, for their time and patience during assessment; .. . Dr. Donald T. Stuss, my supervisor, for his mentorship, guidance, and direction; ... my thesis committee members, Dr. Mary Lou Smith and Dr. Gordon Winocur for their insightful input; ... my collegues within the Department of Occupational Therapy at the University of Toronto for their support; ... and most importantly my husband, family, and friends for their ongoing encouragement and confidence in a successfuI conclusion. I would also like to acknowledge the financial support for my doctoral studies received from the Ontario Ministry of Health as a Health Research Personnel Development Program Fellowship. -. -