Subjective quality of life following traumatic brain injury

Traumatic brain injury (TBI) can cause impairment of functioning, that disrupts critical aspects of psychosocial functioning such as work, interpersonal relationships, and participation in recreational activity (Jennett, 1997; Seibert et al., 2002; Tate, Lulham, Broe, Strettles, & Pfaff, 1989). As such, TBI affects the quality of life of those who suffer its ongoing effects (Ponsford, Sloane, & Snow, 1996; Tennant, Macdermott, & Neary, 1995). Although many TBI rehabilitation services state their aims as being to optimize quality of life following injury, there has been very little research in this area. Reasons for this include ambiguity in conceptualisation of quality of life and lack of consensus about appropriate measures. Building on recent international consensus group recommendations (e.g., Bullinger, 2002; National Institutes of Health [NIH], 1999), this thesis addressed some fundamental gaps in knowledge in the TBl/QOL field. This project aimed to provide an understanding of SQOL outcome and ultimately develop predictive models of SQOL outcome following TBI. The project utilized outcome data from a large population-based sample, collected prospectively by the Neurotrauma Register of Tasmania. In summary, Study 1 identified an appropriate measure of subjective quality of life (SQOL), Frisch's (1994) Quality of Life Inventory (QOLI) and found it was sensitive and appropriate for adults with TBI. However, no research had been conducted with the QOLI within the TBI population. Study 2 confirmed a three-factor structure for the QOLI using both exploratory and confirmatory factor analysis and identified only subtle differences between the US-based normative distribution and pre-injury estimates of a sample of 470 people with TBI. Study 3 reported SQOL outcome over four time-points to 12 months following injury for the QOLI Total and QOLI Factor scores with a sample of 663 participants. Significant deterioration was observed in QOLI scores at one and three months following injury, returning to near pre-injury estimates by six months. Study 4 examined outcomes and relationships between a large number of potential predictive variables identified from previous research with QOLI outcomes. A number of important predictive variables were identified across the five domains suggested by Berger, Leven, Pirente, Bouillon, & Neugebauer (1999). Study 5 used regression modeling to confirm predictive models of SQOL outcome at one, three, six and twelve months following TBI and provided a means of identifying those at risk of poor outcome. This fundamental TBl/SQOL research provides clinicians and researchers with the structure as well as pre and post injury normative distributions of an appropriate measure of SQOL. The predictive models produced by this analysis explained more variance than models reported in previous research, correctly predicting participants' SQOL outcome to within a single point in over 70% of cases. The predictive models will be valuable for rehabilitation clinicians who wish to identify people who are at risk of poorer outcome. Building on the results of this project, there are many avenues for further research. These include extending the methodology to predict SQOL outcome over two, five or more years following injury, and developing effective interventions that facilitate restoration of SQOL following TBI.