Adaptability to Balance Perturbations During Walking as a Potential Marker of Falls History in Older Adults

Falls most commonly occur during walking due to unexpected balance perturbations like trips and slips. Walking-based balance assessment including walking stability and adaptability to such perturbations could be beneficial for fall risk assessment in older adults. This cross-sectional study reanalyzed data from two larger studies conducted with the same walking protocol. Participants walked unperturbed at speeds of 0.4 m/s up to 1.8 m/s in 0.2 m/s steps. Ten unannounced treadmill belt acceleration perturbations were applied while participants walked at equivalent stability, assessed using margins of stability. Retrospective (12 months) falls incidence was collected to divide participants into groups. Twenty older adults (mean age 70.2±2.9 years) were included; 8 with and 12 without falls history. No significant differences were found in unperturbed walking parameters or their variability. Overall perturbation-recovery step behavior differed slightly (not statistically significant) between groups after the first perturbation and differences became more pronounced and significant after repetition of perturbations. Non-fallers significantly reduced the number of recovery steps needed across the trials, whereas fallers did not show these improvements. Fallers tended to have slightly delayed and more variable recovery responses after perturbation compared to non-fallers. Non-fallers demonstrate more signs of adaptability to repeated perturbations. Adaptability may give a broader indication of the ability of the locomotor system to respond and improve responses to sudden walking perturbations than unperturbed walking variability or recovery to a single novel perturbation. Adaptability may thus be a more useful indicator of fall risk in older adults and should be considered in further research.