Reaction time and variability 5 and 10 years after traumatic brain injury.

Improvement in performance can occur up to 10 years after traumatic brain injury (TBI). Few previous studies have examined the long-term effects of TBI on information processing. This study used reaction time (RT) tasks of increasing complexity with 10-year post-injury, 5-year post-injury, and control groups to assess any such effects. There were no significant group differences in mean RT; however, in the groups of persons with head injury only, response latency was related to age and to task demands. Older members of the groups of persons with head injury were slower than controls. The variability in performance was significantly higher in the 5-year post-injury group than in both the 10-year group and the control group. There were no significant differences among the groups in their ability to inhibit the processing of redundant information. There were no correlations between any dependent measure and severity of injury. Speed of processing is more sensitive to task complexity in individuals with head injury, but only when age at injury is considered. Most importantly, for rehabilitation purposes, recovery of consistency in performance can be expected more than 5 years after a TBI.