Few studies have assessed the long-term functional outcomes of traumatic brain injury (TBI) in large, well-characterized samples. Using the Traumatic Brain Injury Model Systems cohort, this study assessed the maintenance of independence between years 5 and 15 post-injury and risk factors for decline. The study sample included 1381 persons with TBI who received inpatient rehabilitation, survived to 15 years post-injury, and were available for data collection at 5 or 10 years and 15 years post-injury. The Functional Independence Measure (FIM) and Disability Rating Scale (DRS) were used to measure functional outcomes. The majority of participants had no changes during the 10-year time frame. For FIM, only 4.4% showed decline in Self-Care, 4.9% declined in Mobility, and 5.9% declined in Cognition. Overall, 10.4% showed decline in one or more FIM subscales. Decline was detected by DRS Level of Function (24% with >1-point change) and Employability (6% with >1-point change). Predictors of decline factors across all measures were age >25 years and, across most measures, having less than or equal to a high school education. Additional predictors of FIM decline included male sex (FIM Mobility and Self-Care) and longer rehabilitation length of stay (FIM Mobility and Cognition). In contrast to studies reporting change in the first 5 years post-TBI inpatient rehabilitation, a majority of those who survive to 15 years do not experience functional decline. Aging and cognitive reserve appear to be more important drivers of loss of function than original severity of the injury. Interventions to identify those at risk for decline may be needed to maintain or enhance functional status as persons age with a TBI.
Keywords: brain injuries; cognition; disabled persons; function; prognosis; rehabilitation outcome.