Late contributions of repetitive head impacts and TBI to depression symptoms and cognition

Objective To test the hypothesis that repetitive head impacts (RHIs), like those from contact sport play and traumatic brain injury (TBI) have long-term neuropsychiatric and cognitive consequences, we compared middle-age and older adult participants who reported a history of RHI and/or TBI with those without this history on measures of depression and cognition. Methods This cross-sectional study included 13,323 individuals (mean age, 61.95; 72.5% female) from the Brain Health Registry who completed online assessments, including the Ohio State University TBI Identification Method, the Geriatric Depression Scale (GDS-15), and the CogState Brief Battery and Lumos Labs NeuroCognitive Performance Tests. Inverse propensityweighted linear regressions accounting for age, sex, race/ethnicity, and education tested the effects of RHI and TBI compared to a non-RHI/TBI group. Results A total of 725 participants reported RHI exposure (mostly contact sport play and abuse) and 7,277 reported TBI (n = 2,604 with loss of consciousness [LOC]). RHI (beta, 1.24; 95% CI, 0.36-2.12), TBI without LOC (beta, 0.43; 95% CI, 0.31- 0.54), and TBI with LOC (beta, 0.75; 95% CI, 0.59-0.91) corresponded to higher GDS-15 scores. While TBI with LOC had the most neuropsychological associations, TBI without LOC had a negative effect on CogState Identification (beta, 0.004; 95% CI, 0.001-0.01) and CogState One Back Test (beta, 0.004; 95% CI, 0.0002-0.01). RHI predicted worse CogState One Back Test scores (beta, 0.02; 95% CI, -0.01 to 0.05). There were RHI x TBI interaction effects on several neuropsychological subtests, and participants who had a history of both RHI and TBI with LOC had the greatest depression symptoms and worse cognition. Conclusions RHI and TBI independently contributed to worse mid- to later-life neuropsychiatric and cognitive functioning.