APOE genotype and neuropsychological outcome in mild-to-moderate traumatic brain injury: A pilot study

Primary objective: The influence of apolipoprotein (APOE) on neuropsychological outcome was investigated in 19 patients (25.79 +/- 7.22 years) with mild-to-moderate traumatic brain injury and 14 matched healthy control subjects (27.43 +/- 6.65 years). Research design: Within- and between-group comparisons were employed. Methods and procedure: APOE genotype was determined using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method. Verbal learning and memory, speed of processing and executive function were assessed at 6 weeks and 6 months post-injury. A three-way [Group(star)Type(star)Time] ANOVA with repeated measures on the third factor was employed to determine the differences between groups and APOE genotype. Main outcomes and results: No Group(star)APOE Genotype(star)Time interaction was found for all neuropsychological measures, Auditory Verbal Learning Test (p = 0.484, eta(2) = 0.017), Trail Making Test-B (p = 0.454, eta(2) = 0.019), Controlled Oral Word Association (p = 0.107, eta(2) = 0.087) and Wisconsin Card Sorting Test-64 (p = 0.291, eta(2) = 0.038). The results of this pilot study support earlier findings that showed no relationship between APOE epsilon 4 and poor recovery in the same population. Conclusion: The preliminary findings suggest no clear APOE genotype influence on neuropsychological outcome in mild and moderate TBI patients. Large-scale studies with longer follow-up duration are warranted.