The development and feasibility of treadmill-induced fall recovery training applied to individuals with chronic stroke

Abstract

Background: Exercise has failed to reduce falls in those with chronic stroke. A limitation of traditional exercise is that the motor responses needed to prevent a fall are not elicited (i.e. they lack processing specificity). Balance reactions often require compensatory steps. Therefore, interventions that target such steps have the potential to reduce falls. Computerized treadmills can deliver precise, repeatable, and challenging perturbations as part of a training protocol. The objective of this study was to develop and determine the feasibility of such training applied to those with chronic stroke. We developed the training to address specificity, appropriate duration and repetition, and progressive overloading and individualization. We hypothesized that our intervention would be acceptable, practical, safe, and demonstrate initial signs of efficacy.

Methods: In this single-arm study, thirteen individuals with chronic stroke (29-77 years old, 2-15 years post stroke) performed up to six training sessions using a computer-controlled treadmill. Each session had separate progressions focused on initial steps with the non-paretic or paretic limbs in response to anterior or posterior falls. Perturbation magnitudes were altered based on performance and tolerance. Acceptability was determined by adherence, or the number of sessions completed. Practicality was documented by the equipment, space, time, and personnel. Adverse events were documented to reflect safety. In order to determine the potential-efficacy of this training, we compared the proportion of successful recoveries and the highest perturbation magnitude achieved on the first and last sessions.

Results: The training was acceptable, as evident by 12/13 participants completing all 6 sessions. The protocol was practical, requiring one administrator, the treadmill, and a harness. The protocol was safe, as evident by no serious or unanticipated adverse events. The protocol demonstrated promising signs of efficacy. From the first to last sessions, participants had a higher proportion of successful recoveries and progressed to larger disturbances.

Conclusions: Using a computerized treadmill, we developed an approach to fall-recovery training in individuals with chronic stroke that was specific, considered duration and repetition, and incorporated progressive overloading and individualization. We demonstrated that this training was acceptable, practical, safe, and potentially beneficial for high-functioning individuals with chronic stroke.

Trial registration: Retrospectively registered at clinicaltrials.gov ( NCT03638089 ) August 20, 2018.

Keywords: Balance; Falls; Perturbation training; Rehabilitation; Stability.

Fig. 1

A flowchart depicting a single fall-recovery training session. Participants performed training in this order for each of the six training sessions

Fig. 2

Individuals with chronic stroke participate in trip-recovery (left) and slip-recovery (right) training. Treadmill-induced disturbances were applied to standing participants, necessitating steps to prevent a fall into a safety harness. On the left, a participant fell in response to a simulated trip (a = 4.5 m/s²) on the first training session. On the last training session, he successfully recovered from the same disturbance, initially stepping with his paretic limb. On the right, a participant fell in response to a simulated slip (a = 5.0 m/s²) during the first session. On the last training session, he successfully recovered from the same disturbance, initially stepping with his non-paretic limb