Comparing Cognitive-Motor Interference Across Younger, Middle-Aged, and Older Adults During Dual-task Walking

INTRODUCTION: Walking while listening or talking is a functionally relevant cognitive-motor dual-task (DT) activity that may challenge attentional capacity. DT activity alters gait and increases falls risk. The aging process may magnify challenges in DT performance. This study compared cognitive-motor interference (CMI) and DT performance across younger, middle-aged, and older adults during walking under varying memory task types. METHODS: A cross-sectional sample of 32 younger (mean age=25),18 middle-aged (mean age=56), and 19 older (mean age=73.6) healthy adults completed walking trials under single-task (ST) and four DT conditions with different memory-based tasks, two auditory encoding (story memory and list encoding), and two verbal retrieval (verbal fluency and list retrieval). Participants wore sensors that transmitted spatiotemporal walking data to a mobile iOS device. Gait parameters (speed (m/s), stride time (s), stride time variability (%CoV)) and memory performances were measured under ST and DT conditions. DT effects (DTE) were calculated for all measures to quantify CMI, the percent change in performance under DT relative to ST. Statistical analyses included ANOVAs with post hoc tests and correlations with age. RESULTS: We found a decreasing trend in DTgait performance and worsening CMI across conditions with advancing age (for example, DT verbal fluency gait speed: younger= 1.10m/s DTE= -15%; middle-aged= 0.98m/s DTE= -18%, older= 0.82m/s DTE= -24%). ANOVA showed differences between the 3 age groups in the DTE of all memory tasks on the gait measures (p<0.05), with the DTE being consistently higher (worse) in older than younger adults. Middle-aged and older adults did not differ in DTE on speed or stride variability under memory retrieval tasks, but the latter had greater DTE on speed under memory encoding tasks. Middle-aged adults had similar DTE on gait measures to younger adults under encoding tasks, but greater on stride time and variability under retrieval tasks. Groups had similar DTE on memory tasks. CONCLUSION: Age-related differences in CMI were more prominent for gait than for memory tasks. Findings support that DT performance incrementally declines with age. Middle-aged and older adults had similar gait destabilization in different DT walking demands, but older adults had higher interference with DT walking of auditory processing demands. Retrieval tasks during walking expose early deficits in middle-aged adults that differentiate them from younger adults. Results further suggest assessing DT walking of different demands and beginning from middle age to reduce fall risk and enhance DT ability early in life via education or cognitive-motor training.