Physiological and Cognitive Determinants of Gait Variability of Asian Population: The Yishun Study.

INTRODUCTION: Gait variability is associated with frailty, dementia, and falls. Studies on the association of physiological and cognitive factors with gait variability have seldom included middle-aged adults, even though these adults already experienced loss of muscular strength and postural stability. This study aimed a) to examine and compare the trend of gait variability in men and women, across the adult age spectrum, and b) to identify and compare the contributions of physiological and cognitive factors to gait variability. METHODS: This was a population-based cross-sectional study at a single center. A random sample of 507 community-dwelling, well-functioning adults aged 21-90 years were studied. Cognition was measured using the Repeatable Battery for the Assessment of Neuropsychological Status. Physiological factors examined included visual contrast sensitivity (VCS), postural sway, hand reaction time, handgrip strength (HGS), knee extensor strength, and gait variability (coefficient of variation [CoV]). Multivariable regression models were used to examine the association between physiological and cognitive performance with gait CoV. RESULTS: Women walked with greater stride width CoV (p < 0.01) and double support time (DST) CoV (p < 0.01) than men. The stride width (p = 0.01) and DST variability (p = 0.03) were significantly higher in older men as compared to men in younger age-groups. Gait speed accounted for most of the gait CoV variances and attenuated the effects of physiological performance and/or attention cognition on most gait variability, except for CoV of DST and stride width. Adults with better VCS (ß = -0.19), faster hand reaction (ß = 0.12), and greater HGS (ß = -0.15) had lower variability in step length. CONCLUSION: The trends of stride width CoV and DST CoV across adult age spectrum were different between men and women. Greater stride width variability was partly attributed to greater HGS, possibly to better control lateral stability during walking. Physiological factors outweigh cognition in regulating most of the gait CoV in this study. They are modifiable and potential targets for healthy aging program.

Physiological and Cognitive Determinants of Dual-Task Costs for Gait Parameters: The Yishun Study.

BACKGROUND: Studies indicate that physiological and cognitive aging are causally related and functionally interdependent. However, the relative contribution of physiological factors and cognition to dual-task costs (DTC) of gait parameters has not been well studied. In this cross-sectional study, we examined the trajectory of DTC of gait parameters across the adult age spectrum for both sexes and identified the contributions of physical and cognitive performance to DTC of gait. METHODS: A total of 492 community-dwelling adults, aged 21-90 years, were randomly recruited into the study. Participants were divided into 7 age groups, with 10-year age range for each group. Demographic data, height, body mass, education level, and information on comorbidities were recorded. Cognition was measured using the Repeatable Battery for the Assessment of Neuropsychological Status. Physical performance included visual contrast sensitivity, postural sway, hand reaction time, handgrip strength, knee extensor strength, and single-task and dual-task gait assessments. Stepwise multivariable regression was used to examine the association between physical and cognitive performance with DTC of gait parameters. RESULTS: Women were found to have significantly higher DTC of gait speed (p = 0.01), cadence (p < 0.01), and double support time (p < 0.01) than men. However, significant aging effect on DTC of gait speed (p = 0.01), step length (p = 0.01), and double support time (p = 0.01) was observed in men but not in women. Immediate memory was the primary determinant for the DTC of gait speed (ß = -0.25, p < 0.01), step length (ß = -0.22, p < 0.01), and cadence (ß = -0.15, p = 0.03) in men. Besides immediate memory, postural sway (ß = -0.13, p = 0.03) and hand reaction (ß = 0.14, p = 0.02) were also significantly associated with DTC of step length and cadence, respectively, in women. CONCLUSION: There were sex differences in the amplitude and trajectories of DTC of gait parameters. The DTC increased with age in men but not in women. Immediate memory was the primary determinant of DTC of gait parameters in men while immediate memory, postural sway, and reaction time were associated with DTC of gait in women. Future studies should investigate the clinical implications of the sex differences in the DTC with fall risks.

Reference Values of Gait Speed and Gait Spatiotemporal Parameters for a South East Asian Population: The Yishun Study.

BACKGROUND: Age-related slowing of gait has been reported to start as early as the fifth decade and accelerate beyond the seventh decade of life. A single cut-off for slow gait may not be appropriate for men and women of different ages. We aimed to report reference values for gait speed and spatiotemporal gait parameters of adult age groups in a South East Asian population. METHODS: A total of 507 community-dwelling adults, aged 21-90 years were recruited into the study through random sampling, filling quotas of 20-40 participants in each sex and age group (10-year age groups between 21 and 60 years; 5-year age groups beyond age 60 years). Demographic data, height, weight and information on comorbidities were recorded. Habitual gait speed and spatiotemporal parameters were measured, and the average of three trials was recorded using the GAITRite system. RESULTS: Gait speed peaked in their 40s for both men and women, but the trajectories differed slightly across age groups. Although similar for men in their 50s and 60s, gait speed was significantly slower among those aged 71 years and older. For women beyond 50 years old, gait slowed with age. After adjusting for height, women were found to walk significantly faster and with a longer step length than men. Women also walked with a significantly narrower stride width and less external rotation of the feet. The lowest quintile for gait speed in our study cohort was 0.9m/s, below the recommended cut-off of 1.0m/s. CONCLUSION: We established the reference values as well as the quintiles for gait speed and spatiotemporal gait parameters across adult age groups in a multi-ethnic Asian population. This contributes to a valuable database for gait assessment and evaluation of preventive or rehabilitative programs.