P2‐315: Cognitive function and mobility disability in older adults with amnestic mild cognitive impairment

Abstract

Older adults with amnestic mild cognitive impairment (aMCI) are at higher risk for Alzheimer's disease (AD). Declining physical performance is associated with declining cognitive function in older adults with aMCI. Understanding relationships between indicators of mobility disability and AD severity is important for the prevention of adverse outcomes such as mobility limitations and falls. This study was a cross sectional analysis of baseline measures from a Randomized Controlled Trial, “Resources and Activities for Lifelong Independence” (NIA/NIH 2R01AG14777-06A2, PI: Linda Teri, PhD). Participants were older adults (≥ 70 years old) with aMCI. Physical Performance Measures: The Short Physical Performance Battery (SPPB) was used to assess lower extremity function and completion of the 400-meter walk was used to measure mobility disability. Cognitive Function Measures: The Alzheimer's Disease Assessment Scale (ADAS-Cog) was used to assess dementia severity. Wechsler Logical Memory and Trail Making tests were used to assess memory, attention, and executive function. Covariates: Geriatric Depression Scale (GDS) and age.Analysis: Independent t-tests were applied to examine mean differences based on the SPPB (score <8 vs. ≥ 8). Multiple linear and logistic regression were used to examine associations between ADAS-Cog, SPPB and 400-meter walk. Participants with low SPPB scores (n = 98) compared to high SPPB scores (n = 101) were older (P <.001) and had higher GDS scores (P = .012). Participants with low SPPB scores performed significantly worse on the ADAS-Cog (P = .001), Trail Making A (P = .014), Trail Making B (P = .007), and Logical Memory II (P = .018). Individuals unable to complete the 400-meter walk had higher GDS scores (P = .001) and worse Trail Making B scores (P = .01). Applying multiple linear regression, lower scores on the SPPB were associated with higher (worse) scores on the ADAS-COG after adjusting for age and GDS (β = -.21, P = .02). Applying logistic regression, the ADAS-Cog was not associated with ability to complete the 400-meter walk (OR = 0.96, 95% CI .88-1.05, P = .34). In this study of older adults with aMCI, reduced lower extremity function was associated with worse cognitive function. These findings support a relationship between indicators of mobility disability and cognitive function in older adults with aMCI.