Concussion-related deficits in the general population predict impairments in varsity footballers.

ABSTRACT

OBJECTIVE: We investigated the long-term cognitive effects of concussion in 19,261 members of the general population and a cohort of varsity American football players with a history of frequent head impacts, using tests that are known to be sensitive to small changes in performance. METHODS: We asked 19,261 participants to complete a demographic questionnaire and 12 cognitive tests measuring aspects of executive function, including inhibitory control. We compared the performance of those reporting a history of concussion (post-concussion) to those reporting no history of concussion (non-concussed) on the cognitive battery and four non-cognitive variables. We used the results of this population-level study to predict the profile of cognitive performance in varsity American football players, who completed the same cognitive tasks. RESULTS: Post-concussion and non-concussed participants did not differ on 11 of the 12 cognitive tasks employed. However, on a test of inhibitory control based on the classic Stroop paradigm, post-concussion participants showed accuracy-related impairments specific to the incongruent conditions of the task. Post-concussion participants reported higher levels of anxiety, depression, and trouble concentrating. An entirely independent sample of 74 varsity American football players demonstrated the same pattern of impairment compared to healthy controls, they scored significantly lower on the test of inhibitory control but were indistinguishable from controls on the 11 other tasks. INTERPRETATION: Self-reported concussion is not associated with long-term general effects on cognitive function. Nevertheless, those who report at least one concussion and those who expose themselves to long-term frequent sport-related head impacts do have a modest, but statistically robust, deficit of inhibitory control.