Sports-related concussion not a culprit of long-term cognitive or behavioural deficit

Individuals with sports-related concussion (SRC) in the general population showed no long-term cognitive or behavioural deficits compared with those have not had concussion, a study has found.

The PROTECT-TBI study, a longitudinal cohort study of community-dwelling adults (n=15,214; age, 50–90 years; male, 24 percent) in the UK, was conducted between November 2015 and November 2020, with up to 4 years of annual follow-up. Lifetime history of concussions was collected at baseline using the Brain Injury Screening Questionnaire, and the effect of type and number of concussions on cognitive scores at baseline (working memory, verbal reasoning, processing speed and attention), score trajectories over time, as well as behavioural outcomes (using the Mild Behavioural Impairment-Checklist [MBI-C]) were assessed. [J Neurol Neurosurg Psychiatry 2025;96:397-405]

Concussion (mild or symptomatic traumatic brain injury [TBI]) was defined as a head injury followed by loss of consciousness (LOC) of <30 minutes or a dazed or confused episode.

Compared with individuals in the no concussion group, those in the SRC and mixed concussion groups (SRC + non-SRC [nSRC]) were substantially more likely to be male (57.3 and 58 percent, respectively, vs 19.2 percent; p<0.001). At baseline, individuals in the SRC group were found to have significantly better working memory and verbal reasoning compared with those who had never suffered concussion (p=0.003 and p<0.001, respectively). For behavioural outcomes, individuals in the nSRC and mixed concussion groups had significantly worse MBI-C scores compared with the no concussion group (both p<0.001). No significant differences in various groups score trajectories with increasing age were found.

Analysis of the effect of number of concussions (0, 1, 2 or ≥3 SRC or nSRC) found that, compared with those with no SRC at baseline, those who had suffered one (but not more) SRC had significantly better verbal reasoning and attention (p=0.006 and p=0.010, respectively). For nSRCs, compared with those without nSRC, those with ≥3 nSRCs had significantly worse processing speed and attention (p=0.010 and p=0.001, respectively) as well as worse trajectory of verbal reasoning with increasing age (p=0.005). Each additional nSRC was also associated with progressively worse attention (p<0.001). For behavioural outcomes, those with any number of nSRCs had significantly worse MBI-C scores vs those without nSRC, while there was no significant difference in the scores for SRCs vs no SRC.

TBI can increase dementia risk by 1.5–3 times, and estimates indicate that TBI contributes 5–15 percent of the current dementia burden. The impact of SRC (mild TBI) on long-term cognitive outcomes and dementia has been vigorously debated. [J Neurol Neurosurg Psychiatry 2019;90:1221-1233]

“Given our understanding of the pathophysiology of concussion, it is clear that there is something other than the head injury itself that underlies the better cognitive outcomes in [the SRC] group,” wrote the authors.

“One possibility is that lifetime physical activity has a cumulative, greater positive impact on cognition… Alternatively, involvement in sports may be associated with greater lifetime social connectivity, which is also known to be associated with lower rates of cognitive decline and dementia. It is also likely that sports-related physical, social and economic benefits that may offset the cognitive risks of SRC are not present in the same way for concussions associated with falls, assaults and motor vehicle accidents,” the authors postulated.