Bidirectional associations between word memory and one-legged balance performance in mid and later life.

Joanna M Blodgett,Rebecca Hardy,Diana Kuh,Daniel H J Davis,Rachel Cooper

doi:10.1016/j.exger.2020.111176

Abstract

BackgroundAge-related changes in cognitive and balance capabilities are well-established, as is their correlation with one another. Given limited evidence regarding the directionality of associations, we aimed to explore the direction and potential explanations of associations between word memory and one-legged balance performance in mid-later life.MethodsA total of 3062 participants in the Medical Research Council National Survey of Health and Development, a British birth cohort study, were included. One-legged balance times (eyes closed) were measured at ages 53, 60–64 and 69 years. Word memory was assessed at ages 43, 53, 60–64 and 69 with three 15-item word-recall trials. Autoregressive cross-lagged and dual change score models assessed bidirectional associations between word memory and balance. Random-effects models quantified the extent to which these associations were explained by adjustment for anthropometric, socioeconomic, behavioural and health status indicators.ResultsAutoregressive cross-lagged and dual change score models suggested a unidirectional association between word memory and subsequent balance performance. In a sex-adjusted random-effects model, 1 standard deviation increase in word memory was associated with 9% (7,12%) higher balance performance at age 53. This association decreased with age (−0.4% /year (−0.6,-0.1%). Education partially attenuated the association, although it remained in the fully-adjusted model (3% (0.1,6%)).ConclusionsThere was consistent evidence that word memory is associated with subsequent balance performance but no evidence of the reverse association. Cognitive processing plays an important role in the balance process, with educational attainment providing some contribution. These findings have important implications for understanding cognitive-motor associations and for interventions aimed at improving cognitive and physical capability in the ageing population.

Highlights

As both cognitive and balance abilities decline with age, associations between measures are frequently found
In a large nationally representative study with multiple measure ments of word memory and balance performance over 26 years, there was consistent evidence that higher word memory was associated with better subsequent balance performance
When the model was adjusted for covariates, only education had a meaningful impact on estimates. These results suggest that cognition, as assessed by word memory, may play an important role in balance ability, with educational attainment partially explaining this association

Summary

Introduction

As both cognitive and balance abilities decline with age, associations between measures are frequently found. Functional decline in areas of the brain responsible for integrating sensory and motor information could impact an individual’s balance ability This may include fronto-parietal areas, the right cerebellum, and basal ganglia structures (Emch et al, 2019). In a sex-adjusted random-effects model, 1 standard deviation increase in word memory was associated with 9% (7,12%) higher balance performance at age 53. This association decreased with age (− 0.4% /year (− 0.6,-0.1%). Cognitive processing plays an important role in the balance process, with educational attainment providing some contribution These findings have important implications for understanding cognitive-motor associations and for interventions aimed at improving cognitive and physical capability in the ageing population

Objectives

Methods

Results

Discussion

Conclusion