Learning from laboratory-induced falling: long-term motor retention among older adults

Abstract

Falls in older adults are a major health and societal problem. It is thus imperative to develop highly effective training paradigms to reduce the likelihood of falls. Perturbation training is one such emerging paradigm known to induce shorter term fall reduction in healthy young as well as older adults. Its longer term benefits are not fully understood, however. The purpose of this study was to determine whether and to what degree older adults could retain their fall-resisting skills acquired from a single perturbation training session. Seventy-three community-dwelling older adults (≥65 years) received identical single-session perturbation training consisting of 24 slips. This was delivered through unannounced unlocking (and mixed with relocking) of low-friction movable sections of the walkway. A single retest was subsequently scheduled based on a three-stage sequential, pre-post-retest design. Outcome measurements, taken upon the first (novel) and the 24th (final) slips of the initial session and the retest slip, included fall-or-no-fall and stability (quantified by the shortest distance from relative motion state of the center-of-mass and the base-of-support to the limits of stability) at instants prior to (proactive) and after (reactive) the onset of the slip. The training boosted subjects' resilience against laboratory-induced falls demonstrated by a significant reduction from 42.5 % falls on the first slip to 0 % on the 24th slip. Rate of falls which occurred during the laboratory retest remained low in 6-month (0 %), 9-month (8.7 %), and 12-month retest (11.5 %), with no significant difference between the three time intervals. Such reduction of laboratory-induced falls and its retention were attributable to the significant training-induced improvement in the proactive and reactive control of stability. This unique pre-post-retest design enabled us to provide scientific basis for the feasibility of a single session of perturbation training to "inoculate" older adults and to reduce their annual risk of falls in everyday living.

Can augmented feedback facilitate learning a reactive balance task among older adults?

“…However, it is possible that, for participants in the current study, the task was not sufficiently challenging for participants to show improvement throughout the acquisition period. Alternatively, others have reported acquisition and long-term retention of reactive balance tasks among older adults with few practice trials (Bhatt et al 2012;Pai et al 2014). These authors have speculated that the threat to postural stability and risk of fall-related injury imposed by external postural perturbations drives this rapid learning (Bhatt et al 2012); a similar process could underlie the large improvements in postural control early in the acquisition period in the current study.…”

A systematic review of gait perturbation paradigms for improving reactive stepping responses and falls risk among healthy older adults

“…Improvement in limb support & stability in the first 3 trials with no further improvement.Pai et al [57] n  = 67, 44♀, 72 ± 5.5y. Community dwelling, healthy.Slip (low friction moveable platform; slid up to 90 cm forward at foot contact).24 slips in 37 gait trials.Retrospective falls data 12mo preceding & 12mo prospective following the session.Reduction in falls 12mo post-session compared to 12mo pre-session (15% compared to 34% incidence).Pai et al [63]3 groups tested +6, +9 & +12mo respectively: +6mo: n  = 24, 13♀ 74.6 ± 5.8y; +9mo: n  = 23, 15♀ 71.8 ± 5.5y; +12mo: n  = 26, 19♀ 72.0 ± 4.7y. All community dwelling, healthy.Slip (low friction moveable platform; slid up to 90 cm forward at foot contact).24 slips in 37 gait trials.Proactive & reactive stability (measured at touchdown of the to-be-perturbed step & the first recovery step respectively).…”

Can Recovery Foot Placement Affect Older Adults’ Slip-Fall Severity?

“…During the slip trial, it could slide freely in the anteroposterior (AP) direction for up to 90 cm forward or 58 cm backward. Once a subject’s right (slipping) foot was detected in contact with the right platform by the force plates (AMTI, Newton, MA) installed beneath the platforms, 24 a computer controlled triggering mechanism would release the platform. The left platform was automatically released after the left (recovery) foot landed on it.…”