The sex specificity of navigational strategies in Alzheimer disease

Alzheimer disease (AD) is associated with navigational impairments that limit functional independence. We have now examined the role of cognitive and perceptual mechanisms in the navigational impairment of AD to test the hypothesis that men and women with AD may focus on different navigational cues. We conducted navigational, neuropsychologic, and psychophysical testing in men and women from 3 groups: older normal controls, patients with mild cognitive impairment, and patients with AD. Men and women showed parallel declines in navigational capacities from the older normal control, to the mild cognitive impairment, to the AD groups with men and women making similar numbers of errors but different types of errors. There were small sex differences in neuropsychologic and psychophysical performance but large sex differences in how those measures related to navigational capacity: men showed strong links between visual motion processing and navigation. Women showed strong links between verbal capacities and navigation. The findings of these cross-sectional comparisons suggest that there may be sex differences in the progressive navigational decline of AD: men and women who are impaired to the same degree may suffer somewhat different patterns of decline with men relying more on visuospatial processing and women relying more on verbal mediation.