Generalization of In-Place Balance Perturbation Training in People With Parkinson Disease

Abstract

Background and Purpose: Reactive balance training improves reactive postural control in people with Parkinson disease (PwPD). However, the extent to which reactive balance training generalizes to a novel, unpracticed reactive balance task is unknown. This study aimed to determine whether reactive training stepping through support surface translations can be generalized to an unpracticed, instrumented tether-release task. Methods: Twenty-five PwPD (70.52 years ± 7.15; Hoehn and Yahr range 1-3) completed a multiple baseline, open-label, uncontrolled pre-post intervention study. Stepping was trained through a 2-week (6-session) intervention with repeated support surface translations. Performance on an untrained tether-release task (generalization task) was measured at 2 baseline assessments (B1 and B2, 2 weeks apart), immediately after the intervention (P1), and 2 months after training (P2). The tether-release task outcomes were the anterior-posterior margin of stability (MOS), step length, and step latency during backward and forward steps. Results: After support surface translation practice, tether-release stepping performance improved in MOS, step length, and step latency for both backward and forward steps compared to baseline (P < 0.05). Improvements in MOS and step length during backward and forward steps in the tether-release task, respectively, were related to stepping changes in the practiced task. However, the improvements in the generalization task were not retained for 2 months. Discussion and Conclusions: These findings support short-term generalization from trained balance tasks to novel, untrained tasks. These findings contribute to our understanding of the effects and generalization of reactive step training in PwPD. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content available at http://links.lww.com/JNPT/A465).