Repeated Split-Belt Treadmill Training Improves Poststroke Step Length Asymmetry

Abstract

Background and objective Previous studies suggest that error augmentation may be used as a strategy to achieve longer-term changes in gait deficits after stroke. The purpose of this study was to determine whether longer-term improvements in step length asymmetry could be achieved with repeated split-belt treadmill walking practice using an error augmentation strategy. Methods 13 persons with chronic stroke (>6 months) participated in testing: (1) prior to 12 sessions of split-belt treadmill training, (2) after the training, and (3) in follow-up testing at 1 and 3 months. Step length asymmetry was the target of training, so belt speeds were set to augment step length asymmetry such that aftereffects resulted in reduced step length asymmetry during overground walking practice. Each individual was classified as a “responder” or “nonresponder” based on whether their reduction in step length asymmetry exceeded day-to-day variability. Results For the group and for the responders (7 individuals), step length asymmetry improved from baseline to posttesting (P < .05) through an increased step length on both legs but a relatively larger change on the shorter step side (P < .05). Other parameters that were not targeted (eg, stance time asymmetry) did not change over the intervention. Conclusions This study demonstrates that short-term adaptations can be capitalized on through repetitive practice and can lead to longer-term improvements in gait deficits poststroke. The error augmentation strategy, which promotes stride-by-stride adjustment to reduce asymmetry and results in improved asymmetry during overground walking practice, appears to be critical for obtaining the improvements observed.

Perception of lower extremity loads in stroke survivors

“…Spatial symmetry has been shown to improve with various types of gait training, such as body weight supported treadmill training, split belt treadmill training, rhythmic facilitation, and traditional physical therapy such as neurodevelopmental treatment (i.e. NDT) (Hassid et al, 1997;Thaut et al, 1997;Patterson et al, 2010;Reisman et al, 2013). Some studies have shown temporary improvements in temporal and kinetic symmetry (Hassid et al, 1997;Reisman et al, 2007), however, others show temporal symmetry remains unchanged after treadmill training or traditional gait rehabilitation (Silver et al, 2000;Den Otter et al, 2006;Reisman et al, 2013).…”

Motor learning in childhood reveals distinct mechanisms for memory retention and re-learning

“…Furthermore, adults show this faster re-learning even if the adapted pattern has been "washed-out" or unlearned, demonstrating memory of a different version of the same motor skill (Huang et al 2011;Malone et al 2011). This faster re-learning is important not only for successful movement in everyday life, but it can also facilitate motor learning in rehabilitation (Reisman et al 2013).…”

Improving Interlimb Coordination Following Stroke: How Can We Change How People Walk (and Why Should We)?

“…Furthermore, a relatively short training period can cause large changes in coordination: for example, hemiparetic individuals with an average step length asymmetry of 0.15m improved this to <0.05m immediately following 15 minutes of split-belt walkingroughly a 67% improvement in symmetry [35]. Improvements reported over the course of a four-week split-belt training study were not as large (~32% change in step length symmetry from pre-to post-training), but these were retained nearly 100% for upwards of 3 months post-training [40].…”

“…In their long-term training study, Reisman et al [40] found that while split-belt training improved step length symmetry, there was no concurrent change in preferred walking speed. Although Kahn and Hornby [24] found improvements in preferred gait speed following unilateral stepping training, there was no correlation between these gains and improvements in step length symmetry.…”

“…Spatiotemporal measures of interlimb coordination (e.g. step length, double support duration) can be made more symmetric in stroke survivors following 10-15 minutes of split-belt walking when the limb with the shorter step length is trained at the faster speed [35,[39][40][41]. Furthermore, a relatively short training period can cause large changes in coordination: for example, hemiparetic individuals with an average step length asymmetry of 0.15m improved this to <0.05m immediately following 15 minutes of split-belt walkingroughly a 67% improvement in symmetry [35].…”