Retention of the “first-trial effect” in gait-slip among community-living older adults

Abstract

"First-trial effect" characterizes the rapid adaptive behavior that changes the performance outcome (from fall to non-fall) after merely a single exposure to postural disturbance. The purpose of this study was to investigate how long the first-trial effect could last. Seventy-five (≥ 65 years) community-dwelling older adults, who were protected by an overhead full body harness system, were retested for a single slip 6-12 months after their initial exposure to a single gait-slip. Subjects' body kinematics that was used to compute their proactive (feedforward) and reactive (feedback) control of stability was recorded by an eight-camera motion analysis system. We found the laboratory falls of subjects on their retest slip were significantly lower than that on the novel initial slip, and the reactive stability of these subjects was also significantly improved. However, the proactive stability of subjects remains unchanged between their initial slip and retest slip. The fall rates and stability control had no difference among the 6-, 9-, and 12-month retest groups, which indicated a maximum retention on 12 months after a single slip in the laboratory. These results highlighted the importance of the "first-trial effect" and suggested that perturbation training is effective for fall prevention, with lower trial doses for a long period (up to 1 year). Therefore, single slip training might benefit those older adults who could not tolerate larger doses in reality.

Error variability affects the after effects following motor learning of lateral balance control during walking in people with spinal cord injury

“…Thus, both proactive and reactive control mechanisms may be involved to counteract the assistance force and maintain balance during walking (Pai & Bhatt, ). This process is consistent with a previous study in older adults when a slip perturbation was delivered during heel contact (Liu, Bhatt, Wang, Yang, & Pai, ). In particular, participants might primarily rely on the force information from the previous step to proactively adjust the ankle relative position at heel contact.…”

Perturbation-Based Balance Training in Postoperative Individuals With Degenerative Cervical Myelopathy

“…A similar observation was made in subacute individuals with stroke, indicating that PBT could facilitate balance recovery under dynamic conditions (Handelzalts et al, 2019). In elderly population, PBT could also improve proactive and reactive stability when individuals encounter slip-like perturbations during level-ground walking (Liu et al, 2017). Moreover, enhanced proprioception observed in this study could also improve the stability under perturbation.…”

Retention of improvement in gait stability over 14 weeks due to trip-perturbation training is dependent on perturbation dose

“…In contrast, retention of the robust effects obtained from multi-trial perturbation training sessions are already well established (Bhatt et al, 2012;Epro et al, 2018b;Pai et al, 2014a). However, to our knowledge only Liu et al (2017) examined this topic, demonstrating that a single slip perturbation exposure can cause long-term retention effects.…”