B - 49 A-Head of the Game: a Preliminary Meta-Analytic Review of Neuropsychological Performance in Individuals Exposed to Repetitive Head Impacts

Abstract Objective We conducted a meta-analysis of the extant neuropsychological literature within individuals exposed to repetitive head impacts (RHI) in order to determine the impact of RHI on neuropsychological ability. Method Standardized search terms were applied in Embase, Scopus, Cochrane, PsycINFO, and PubMed. The search interval covered articles published from 1946 to October 2023. Analyses were random-effects models. Hedge’s g was used as a bias-corrected estimate of effect size. Between-study heterogeneity was assessed using Cochran’s Q and I2. Publication bias was assessed with Duval and Tweedie’s Trim-and-Fill method to identify evidence of missing studies. Results The initial omnibus literature search yielded 2143 studies. 35 studies (10,343 RHI exposed and 5211 referents) met our inclusion criteria of having RHI exposed participants and neuropsychological outcomes. Preliminary results showed RHI exposed individuals demonstrated significantly worse performance overall when compared to referents (k = 35, g = −0.20, p = 0.003; Q = 154.63) with a small effect size. Multiple moderation analyses were conducted examining specific cognitive domains, age, and RHI subgroups, among others. Trim-and-fill procedure estimated seven studies to be missing due to publication bias (adjusted g = −0.06, 95% CI = -0.20, 0.08). Conclusions In our preliminary analysis, individuals exposed to RHI performed slightly worse on average when compared to referents, though this effect was attenuated by accounting for publication bias and differed when accounting for specific moderating variables. Improved methodological standardization within the RHI literature is needed as well as more data collection and greater implementation of longitudinal study designs.