Unexpected perturbations training improves balance control and voluntary stepping times in older adults - a double blind randomized control trial

Abstract

BackgroundFalls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls.MethodsIn a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were recruited and randomly allocated to an intervention group (n = 27) or a control group (n = 26). The intervention group received 24 training sessions over 3 months that included unexpected perturbation of balance exercises during treadmill walking. The control group performed treadmill walking with no perturbations. The primary outcome measures were the voluntary step execution times, traditional postural sway parameters and Stabilogram-Diffusion Analysis. The secondary outcome measures were the fall efficacy Scale (FES), self-reported late life function (LLFDI), and Performance-Oriented Mobility Assessment (POMA).ResultsCompared to control, participation in intervention program that includes unexpected loss of balance during walking led to faster Voluntary Step Execution Times under single (p = 0.002; effect size [ES] =0.75) and dual task (p = 0.003; [ES] = 0.89) conditions; intervention group subjects showed improvement in Short-term Effective diffusion coefficients in the mediolateral direction of the Stabilogram-Diffusion Analysis under eyes closed conditions (p = 0.012, [ES] = 0.92). Compared to control there were no significant changes in FES, LLFDI, and POMA.ConclusionsAn intervention program that includes unexpected loss of balance during walking can improve voluntary stepping times and balance control, both previously reported as risk factors for falls. This however, did not transferred to a change self-reported function and FES.Trial registrationClinicalTrials.gov Registration number: NCT01439451.

Transient visual perturbations boost short-term balance learning in virtual reality by modulating electrocortical activity

“…Both virtual reality training with perturbations and unaltered viewing showed significantly improved performance compared with virtual reality without perturbations. Increased improvement during perturbations training agrees with similar research using unexpected mechanical perturbations during walking to improve balance control (Kurz et al 2016). Comparing the two virtual reality groups, we found no evidence that the perturbation affects the quantity of training errors, subjects' experience of virtual reality, or physical exertion.…”

An Initial Passive Phase That Limits the Time to Recover and Emphasizes the Role of Proprioceptive Information

“…Previously, it was assumed that small and/or predicted internal perturbations can be counteracted with a feed-forward control (APAs) whereas a feedback-based postural muscle activation (CPAs) is the main mechanism of balance restauration to cope with large and/or unexpected perturbations ( 78 , 79 ). However, several studies reported an increase of efficiency in the reactive recovery response after unexpected perturbation training which challenged mechanisms for dynamic stability ( 70 , 80 ).…”

“…Thus, we believe that during a fall from standing height, it takes about 300 ms for postural responses to start correcting the body trajectory, while the impact is expected (to occur) around 700 ms. It has been argued that this time is sufficient to change the way one falls and that this makes it possible to apply safer ways of falling ( 7 , 69 , 70 ), for example by using martial arts fall techniques ( 68 , 71 – 73 ). Despite these constraints, our study also supports the idea that learning is possible even though it may take a large number of trials.…”

Single and multiple step balance recovery responses can be different at first step lift-off following lateral waist-pull perturbations in older adults

“…Overall, the findings indicated that although reduced stability at first foot contact could be a determinant of taking additional steps, stepping responses could also be attributable to the COM motion state as early as first step lift-off, preceding foot contact. Since perturbation training has been reported to improve the reactive control of balance stability (Barrett et al, 2012; Dijkstra et al, 2015; Kurz et al, 2016; Mansfield et al, 2015; Pai et al, 2014; Rosenblatt et al, 2013), which increased balance stability at the instant of step lift-off (Lee et al, 2016; Liu et al, 2016), perturbation-based training interventions aimed at improving the reactive control of stability would reduce initial balance instability at first step lift-off and possibly the consequent need for multiple steps in response to balance perturbations.…”