Impact of Fall-Related Psychological and Physiological Factors on Dual-Task Performance in Older Adults: An Investigation of the Posture-First Hypothesis

Abstract

Objective: The current study examined the moderating effects of fall-related psychological and physiological factors on dual-task (DT) performance and task prioritization strategy in a cohort of non-demented, community-dwelling older adults. Participants and Methods: A cross-sectional sample of 512 non-demented community dwellers (age 65 -- 95 years, 57% female) provided information regarding fall-related psychological factors including completion of a single-item fear of falling (FoF) question and the Activities-specific Balance Confidence (ABC) Scale. These individuals also completed a mobility questionnaire assessing their fall history over the past year as well as a standardized assessment of static balance (Unipedal Stance Test). Participants' gait speed was calculated for both normal walk (NW) and walking-while-talking (WWT) conditions on an instrumented walkway. Cognitive performance was measured by percent accuracy on a Serial 7s subtraction task for both single-task Normal Talk (NT) and dual-task WWT conditions. Results: Adjusted linear mixed effects models revealed that participants with high-risk psychological factors (i.e., FoF, low BC, or combined FoF/low BC) demonstrated less DT cost in gait speed compared to those without these risk factors (i.e., no FoF, high BC, or combined FoF/high BC, no FoF/low BC, no FoF/high BC). Similarly, participants with high-risk physiological factors (i.e., falls, low balance, or combined falls/low balance) demonstrated less dual-task cost in gait speed compared to those without (i.e., no falls, high balance, or combined falls/high balance, no falls/low balance, no falls/high balance). In contrast, with the exception of balance confidence, none of the other fall-related psychological or physiological factors (FoF, fall history, or balance performance) moderated the effect of dual-tasking on Serial 7s cognitive accuracy. Conclusion: Consistent with the posture-first hypothesis, results suggest that older adults with the specific fall-related psychological and physiological risk factors described above may be more likely to prioritize mobility over a cognitively demanding interference task, in order to maintain safety and postural stability under dual-task conditions. With a more complete understanding of the factors influencing attention and mobility functioning in aging, clinicians may be better able to develop effective screening tools and intervention strategies for fall prevention among a rapidly growing population of older adults.