O1‐08‐02: Cognition and gait reveal distinct patterns of association in an aging population

Abstract

With aging and in Alzheimer's disease, various brain functions deteriorate. Most research has focused on cognition, which includes processing speed, memory and executive function. Recent evidence suggests that gait is also affected by aging and AD. Gait, too, consists of various aspects, such as Time (e.g. swing time), Space (e.g. stride length), and Variability (consistency of walking). It is unclear if and how cognitive impairment associates with gait deterioration. We investigated the relation between cognition and gait in community-dwelling elderly. From the Rotterdam Study, 1465 elderly (49 years and older) underwent cognitive testing and assessment of gait. Cognition was tested using a validated test-battery, measuring processing speed, memory, and executive function. Gait was assessed using an electronic walkway. Each person performed 6 regular walks, which yielded a total of 21 variables. PCA was used to group these variables together into three factors: Time (e.g. stride length and velocity), Space (e.g. stride length and width), and Variability (variance of the variables across 6 walks). We used age/sex-adjusted linear regression to relate cognition with gait. Additionally, in multivariate models we adjusted cognitive domains for each other. In univariate analyses we found that all cognitive domains were associated with various aspects of gait. However, in multivariate analyses interesting patterns emerged: certain cognitive domains were only association with certain aspects of gait, whilst the association with other aspects of gait strongly attenuated. Processing speed was associated with Time-aspect of gait (difference in Z-score of Time per SD decrease in cognition -0.22 (-0.34;-0.10), but not Space or Variability. Executive function was associated with Variability (-0.17 (-0.29;-0.04)) and Space (-0.15 (-0.26;-0.03)), but not Time. Memory was not associated with any gait-aspect. The magnitude of effect of these associations correspond to a 10-year deterioration in gait. Cognition and gait are tightly linked with processing speed associating with Time, and executive function associated with Space and Variability. These data provide novel insights into the full clinical spectrum of brain pathology. Future studies should investigate the role of gait in aging, MCI, and Alzheimer's disease.