APOE influences on neuropsychological function after mild head injury -: Within-person comparisons

Objective: To examine the relationship between neuropsychological outcome following mild head injury (MHI) and APOE genotype. Methods: Data from a population-based longitudinal study (n = 3,500) were used to identify 34 adults who experienced MHI during the course of the study. Their pre- and postinjury performances on a battery of nine neuropsychological tests were compared within person, and the postinjury performance was compared with that of age- and gender-matched control subjects. Results: The within-person comparisons showed that participants with at least one APOE epsilon4 allele (n = 11) had a significantly decreased postinjury performance on three of the tests, whereas the postinjury performance for APOE epsilon4-negative participants (n = 23) was unchanged. There was no significant difference in postinjury performance between participants with/without the epsilon4 allele, and neither group was impaired relative to controls. Conclusions: APOE genotype may influence the outcome following an MHI. Pre/postinjury within-person comparisons seem more sensitive than control group comparisons for detecting injury-related effects.