Sex-Specific Interactions Between Hearing and Memory in Older Adults With Mild Cognitive Impairment: Findings From the COMPASS-ND Study.

OBJECTIVES: Hearing loss (HL) in older adults is associated with a decline in performance on cognitive tasks and the risk of developing dementia. However, very few studies have investigated sex-related effects on these associations. A previous study of cognitively healthy older adults showed an association between HL and lower cognitive performance in females only. In the present study, we examined the effects of sex and hearing on cognition in individuals with mild cognitive impairment (MCI). We predicted that females with HL would be more likely to show poorer performance on the cognitive measures compared to females with normal hearing (NH), while cognitive performance in males would not depend on hearing. We further predicted that these auditory-cognitive associations would not depend on test modality, and would thus be observed in females for both auditory and visual tests. DESIGN: Participants were 101 older adults with amnestic MCI (M = 71 years, 45% females) in the Canadian Consortium on Neurodegeneration in Aging (CCNA) COMPASS-ND study. Performance on the Montreal Cognitive Assessment (MoCA), Rey Auditory Verbal Learning (RAVLT), and Brief Visuospatial Memory Test-Revised (BVMT-R) was analyzed to investigate sex-related differences and/or hearing-related differences. Participants were categorized as having NH or HL using two different measures: pure-tone hearing screening results (normal based on a pure-tone threshold < 25 dB HL at 2000 Hz in the worse ear) and speech-in-noise speech reception thresholds (SRTs; normal < -10 dB SNR on the Canadian Digit Triplet Test [CDTT]). RESULTS: Males and female groups did not differ in age, years of education, or other relevant covariates. Yet, females with better hearing on either pure-tone or speech-in-noise measures outperformed their worse hearing counterparts on the MoCA total score. Additionally, females with better hearing were more likely to recall several words on the MoCA delayed recall trial relative to those with worse hearing. Females with NH showed significant correlations between CDTT SRTs and both MoCA and RAVLT scores, while no correlations were observed in males. In contrast, males but not females showed an effect of hearing group on BVMT-R test status. CONCLUSIONS: There were sex-specific differences in auditory-cognitive associations in individuals with MCI. These associations were mostly observed in females and on auditory tests. Potential mechanisms and implications are discussed.

Visual Performance and Cortical Atrophy in Vision-Related Brain Regions Differ Between Older Adults with (or at Risk for) Alzheimer's Disease.

BACKGROUND: Visual impairment is associated with deficits in cognitive function and risk for cognitive decline and Alzheimer's disease (AD). OBJECTIVE: The purpose of this study was to characterize the degree of visual impairment and explore the association thereof with cortical atrophy in brain regions associated with visual processing in individuals with (or at risk for) AD. METHODS: Using the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) dataset, we analyzed vision and brain imaging data from three diagnostic groups: individuals with subjective cognitive decline (SCD; N = 35), mild cognitive impairment (MCI; N = 74), and mild AD (N = 30). We used ANCOVAs to determine whether performance on reading acuity and contrast sensitivity tests differed across diagnostic groups. Hierarchical regression analyses were applied to determine whether visual performance predicted gray matter volume for vision-related regions of interest above and beyond group membership. RESULTS: The AD group performed significantly worse on reading acuity (F(2,138) = 4.12, p < 0.01, ω2 = 0.04) compared to the SCD group and on contrast sensitivity (F(2,138) = 7.6, p < 0.01, ω2 = 0.09) compared to the SCD and MCI groups, which did not differ from each other. Visual performance was associated with volume in some vision-related structures beyond clinical diagnosis. CONCLUSION: Our findings demonstrate poor visual performance in AD and that both group membership and visual performance are predictors of cortical pathology, consistent with the idea that atrophy in visual areas and pathways contributes to the functional vision deficits observed in AD.