The influence of the apolipoprotein e (APOE) gene on subacute post-concussion neurocognitive performance in college athletes

Objective: The purpose of this study was to determine whether the ϵ4 allele of the APOE gene influences neurocognitive outcome following sports-related concussion. It was hypothesized that participants with an ϵ4 allele would show poorer neurocognitive performance and greater neurocognitive variability than those without an ϵ4 allele. Method: Participants included 57 concussed collegiate athletes (77.2% male) who participated in a concussion management program at a large university. All athletes underwent a comprehensive neuropsychological assessment and provided a DNA sample for determination of their APOE genotype. The test battery included measures sensitive to concussion, covering the broad domains of learning and memory, attention, processing speed, and executive functions. Results: The sample was divided into ϵ4 + (n = 20) and ϵ4-(n = 37) groups. No significant differences were found between athletes with and without an ϵ4 allele when examining mean neurocognitive standardized scores (all p > .05; d = 0.16-0.18). However, athletes with an ϵ4 allele were more likely to show a greater number of impaired neurocognitive scores post-injury compared to athletes without an ϵ4 allele, x² (1, N = 57) = 3.96, p = < .05, φ = 0.26. Additionally, athletes with an ϵ4 allele demonstrated greater neurocognitive variability than athletes without an ϵ4 allele, t(55) = ?2.04, p < .05, d = 0.53. Conclusions: This research furthers our understanding of how genetic factors uniquely contribute to neurocognitive performance differences following concussion. Our findings suggest a possible relationship between the ϵ4 allele and post-concussion impairment, as well as between the ϵ4 allele and neurocognitive performance variability, suggesting that the ϵ4 genotype may be a risk factor for less efficient cognitive processing in concussed athletes.