Associations of Word Memory, Verbal Fluency, Processing Speed, and Crystallized Cognitive Ability With One-Legged Balance Performance in Mid- and Later Life.

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

doi:10.1093/gerona/glab168

Abstract

BackgroundCognitive integration of sensory input and motor output plays an important role in balance. Despite this, it is not clear if specific cognitive processes are associated with balance and how these associations change with age. We examined longitudinal associations of word memory, verbal fluency, search speed, and reading ability with repeated measures of one-legged balance performance.MethodUp to 2 934 participants in the MRC National Survey of Health and Development, a British birth cohort study, were included. At age 53, word memory, verbal fluency, search speed, and reading ability were assessed. One-legged balance times (eyes closed) were measured at ages 53, 60–64, and 69 years. Associations between each cognitive measure and balance time were assessed using random-effects models. Adjustments were made for sex, death, attrition, height, body mass index, health conditions, health behaviors, education, and occupational class.ResultsIn sex-adjusted models, 1 SD higher scores in word memory, search speed, and verbal fluency were associated with 14.1% (95% CI: 11.3, 16.8), 7.2% (4.4, 9.9), and 10.3% (7.5, 13.0) better balance times at age 53, respectively. Higher reading scores were associated with better balance, although this association plateaued. Associations were partially attenuated in mutually adjusted models and effect sizes were smaller at ages 60–64 and 69. In fully adjusted models, associations were largely explained by education, although remained for word memory and search speed.ConclusionsHigher cognitive performance across all measures was independently associated with better balance performance in midlife. Identification of individual cognitive mechanisms involved in balance could lead to opportunities for targeted interventions in midlife.

Highlights

Age-related declines in cognitive and physical capability from mid-life onwards are common, with increasing recognition of the interdependency of these two domains; this includes theories of an underlying common cause of ageing [1] and evidence that declines in one domain may contribute directly to declines in the other [2-6]
Adjustments were made for sex, death, attrition, height, body mass nu index, health conditions, health behaviours, education, and occupational class. a Results: In sex-adjusted models, one SD higher scores in word memory, search speed and verbal M fluency were associated with 14.1% (95%CI: 11.3,16.8), 7.2% (4.4,9.9) and 10.3% (7.5,13.0) better balance times at age 53, respectively
In fully-adjusted models, associations p were largely explained by education, remained for word memory and search speed. ce Conclusions: Higher cognitive performance across all measures was independently associated with Ac better balance performance in midlife

Summary

INTRODUCTION

Age-related declines in cognitive and physical capability from mid-life onwards are common, with increasing recognition of the interdependency of these two domains; this includes theories of an underlying common cause of ageing [1] and evidence that declines in one domain may contribute directly to declines in the other [2-6]. Single cognitive tests could identify individuals at risk of poor balance, providing s opportunities for both screening and interventions Understanding these associations earlier in u midlife, either before or in the early stages of decline, is important to prevent or mitigate n loss of independent mobility. A To address important limitations within the current evidence base, our primary aim was to examine M longitudinal associations between four cognitive measures (word memory, verbal fluency, d processing speed, crystallised cognitive ability) at age 53 and one-legged balance performance at te ages 53, 60-64 and 69. Given limited and conflicting evidence in this area, we sought to test if p these associations differed by i) age using repeated balance assessments; or ii) sex; and if they e remained after iii) mutual adjustment for other cognitive measures; and iv) adjustment for c education, other indicators of SEP, health status and health behaviours. We expected associations to weaken after adjustment for SEP, health status and health behaviours

METHODS

RESULTS

Search speed