Characterize the levels of various metrics of repetitive head impacts (RHI) in contact (CS) and non-contact (NCS) sport athletes and determine the extent to which they are associated with fluid cognition.
Collegiate-aged athletes (n = 176) completed semi-structured interviews about participation in contact sport. RHI was operationalized based on current sport (CS/NCS), the cumulative number of years of participation, age at first exposure (AFE), and based on recently proposed traumatic encephalopathy syndrome (TES) categories. The NIH Toolbox Cognition Battery assessed fluid cognition. General linear models compared RHI metrics between CS and NCS athletes and tested associations of RHI measures with fluid cognition.
CS athletes had more years of RHI exposure, higher rates of “extensive” exposure based on TES criteria, and were more likely to have AFE before age 12 relative to NCS (ps  .05). Across all RHI metrics, more or earlier RHI was associated with better episodic memory (ps ≤ .05). Secondary analyses showed this effect was driven by women.
Current results find no evidence that RHI in collegiate-aged athletes is associated with worse neurocognition. Although there was extensive overlap among RHI measures, results demonstrate that categorizing athletes based on their current sport undercounts the lifetime RHI exposure in many NCS athletes.

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