This cohort study investigated the magnitude of neurobehavioral, academic, and ''real world'' deficits over the course of 3 years in children with mild, moderate, and severe traumatic brain injury (TBI), and their individually matched controls. This series of analyses addresses the history of recovery, tracing changes in performance over time. Data on 72 case-control pairs (mild, n = 40; moderate, n = 17; severe, n = 15) were available for three testing times: 3 weeks, 1 year, and 3 years after the resolution of post-traumatic amnesia. The same standardized battery of tests was used at all testing times. The dependent variables in these analyses included individual test results, a variable summarizing results within each of 10 neurobehavioral domains, and an overall score across all domains. Three statistics were calculated for each variable: (1) the ''grand'' mean across the three testing times; (2) the slope (expressing the linear trend in performance); and (3) the change in slope over time (expressing the change in the rate of recovery). Use of the differences between case and control scores controlled for premorbid factors, maturation, and test-retest effects. Results indicate the chronicity of neurobehavioral deficits across all 3 years for moderately and severely injured children. They show a strong improvement rate during the first year, but a negligible rate of change during the following 2 years postinjury in most domains, All three of the time components-grand mean, slope, and change in slope-have significant Spearman correlations with severity ranging up to rho = -.5. Over time, the recovery rate slows down more for those with greater brain injury severity. The greatest slowing of recovery occurs in Performance IQ, adaptive problem solving, memory, and motor skills, as well as on a summary score of overall performance. Given this ''plateauing'' of recovery, achievement of parity with peers by the moderately and severely injured seems unlikely. Mildly injured children, however, exhibit negligible deficits or change in performance over time. (C) 1995 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation
