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

Abstract

Given that 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 completed unperturbed walking trials 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 then applied while participants walked at equivalent stability, assessed using the margins of stability. Retrospective (12 months) falls incidence was collected to divide participants into people with and without a history of falls. Twenty older adults (mean age 70.2 ± 2.9 years) were included in this analysis; eight people with one or more recent falls and 12 people without, closely matched by sex, age and height. No significant differences were found in unperturbed walking parameters or their variability. Overall perturbation-recovery step behavior differed slightly (not statistically significant) between the groups after the first perturbation and differences became more pronounced and significant after repetition of perturbations. The No-Falls group significantly reduced the number of recovery steps needed across the trials, whereas the Falls group did not show these improvements. People with a previous fall 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 marker of falls history in older adults and should be considered in further research.

Perturbation-based balance training: Principles, mechanisms and implementation in clinical practice

“…The obvious advantage of the treadmill in comparison to such overground setups is that predicting when a perturbation will be applied is more difficult, as there is no location-based reference point ( 31 ), which ensures that predictive adjustments in in anticipation of perturbations are reduced [though not necessarily completely absent ( 123 , 155 )]. However, walking on a treadmill can provide additional challenges in some populations at increased fall risk, due to lack of familiarity and the requirement to maintain a specific speed [walking speed can be instantaneously adjusted in an overground setup but maintaining it provides an additional challenge during perturbed treadmill walking ( 205 )]. Another inherent limitation in some setups is that the perturbations themselves may not strictly mimic common causes of falls like slips and trips ( 60 ) despite the subsequent recovery mechanics being suggested to be similar ( 53 , 54 ) (see also Figure 2 in section What is task-specificity in the context of PBT?).…”

Systematic review of candidate prognostic factors for falling in older adults identified from motion analysis of challenging walking tasks

“…Two older adult performance studies assessed fall risk prospectively (Ackermans et al, 2021; Hansson et al, 2021), by following subjects for one year to determine whether they fall, after they performed the challenging walking task. Six studies assessed fall risk retrospectively (Brach et al, 2011; Oh-Park et al, 2011; Uemura et al, 2011; Ackermans et al, 2019; Pieruccini-Faria and Montero-Odasso, 2019; Guadagnin et al, 2020; Gerards et al, 2021), by asking subjects at the time of the walking measurement whether they had fallen in the previous months. Three studies evaluated risk based on physical or mental performance at the time of the walking measurement using clinical tests or questionnaires (Zietz et al, 2011; de Carli et al, 2014; Pan et al, 2016).…”

Perturbation-based Balance Training: Principles, Mechanisms and Implementation in Clinical Practice

“…The obvious advantage of the treadmill in comparison to such overground setups is that predicting when a perturbation will be applied is more difficult, as there is no location-based reference point (McCrum et al, 2017b), which ensures that predictive adjustments in in anticipation of perturbations are reduced (though not necessarily completely absent (Wang et al, 2019b, Dusane and). However, walking on a treadmill can provide additional challenges in some populations at increased fall risk, due to lack of familiarity and the requirement to maintain a specific speed (walking speed can be instantaneously adjusted in an overground setup but maintaining it provides an additional challenge during perturbed treadmill walking (Gerards et al, 2021b)). Another inherent limitation in some setups is that the perturbations themselves may not strictly mimic common causes of falls like slips and trips (Song et al, 2021) despite the subsequent recovery mechanics being suggested to be similar (Owings et al, 2001 (see also Figure 2 in section 2.2).…”