Spatial and Temporal Asymmetries in Gait Predict Split-Belt Adaptation Behavior in Stroke

When I was still having therapy 7 years ago, my PT had colleagues that were studying split-belt treadmills. I wonder how many more years before it is determined whether this is useful or not and what the protocol should be.
http://nnr.sagepub.com/content/28/3/230?etoc

1. Laura A. Malone, PhD1,2
2. Amy J. Bastian, PhD1,2

1. ¹The Johns Hopkins School of Medicine, Baltimore, MD, USA
2. ²The Kennedy Krieger Institute, Baltimore, MD, USA

1. Amy J. Bastian, The Kennedy Krieger Institute, 707 N. Broadway, G05, Baltimore, MD 21205, USA. Email: bastian@kennedykrieger.org

Abstract

Background. Step asymmetries during gait in persons after stroke can occur in temporal or spatial domains. Prior studies have shown that split-belt locomotor adaptation can temporarily mitigate these asymmetries. Objective. We investigated whether baseline gait asymmetries affected how patients adapt and store new walking patterns. Methods. Subjects with stroke and age-matched controls were studied walking at a 2:1 speed ratio on the split-belt during adaptation and assessed for retention of the learned pattern (the after-effect) with both belts at the same speed. Results. Those with stroke adapted more slowly (P < .0001), though just as much as healthy older adults. During split-belt walking, the participants with stroke adapted toward their baseline asymmetry (eg, F = 14.02, P < .01 for step symmetry), regardless of whether the subsequent after-effects improved or worsened their baseline step asymmetries. No correlation was found between baseline spatial and temporal measures of asymmetry (P = .38). Last, the initial spatial and temporal asymmetries predicted after-effects independently of one another. The after-effects in the spatial domain (ie, center of oscillation difference) are only predicted by center of oscillation difference baseline (F = 15.3, P = .001), while all other parameters were nonsignificant (all Ps > .17). Temporal coordination (ie, phasing) after-effects showed a significant effect only from phasing baseline (F = 26.92, P < .001, all others P > .33). Conclusion. This work demonstrates that stroke patients adapt toward their baseline temporal and spatial asymmetries of walking independently of one another. We define how a given split-belt training session would affect asymmetries in these domains, which must be considered when developing rehabilitation interventions for stroke patients.