APOE and Spatial Navigation in Amnestic MCI: Results From a Computer-Based Test

OBJECTIVE: We investigated the association between APOE e4 status and spatial navigation in patients with amnestic mild cognitive impairment (aMCI) and assessed the role of hippocampal volume in this association. METHOD: Participants were 74 patients with clinically confirmed aMCI (33 APOE e4 noncarriers, 26 heterozygous, and 15 homozygous e4 carriers). Body-centered (egocentric) and world-centered (allocentric) spatial navigation in a computerized human analogue of the Morris Water Maze was assessed. Brain MRI with subsequent automated hippocampal volumetry was included. RESULTS: Groups were similar in neuropsychological profile. Controlling for age, sex, education, and free memory recall, the APOE e4 carriers performed more poorly on all spatial navigation subtasks (ps .05), but not in the egocentric subtask (p < .001). CONCLUSIONS: Using an easy-to-use, computer-based tool to assess spatial navigation, we found spatial navigation deficits to worsen in a dose-dependent manner as a function of APOE e4 status. This was at least partially due to differences in right hippocampal volume.