Dynamic Postural Stability Among Individuals With Parkinson's Disease Following Performance-Based Overground Locomotor Training

Abstract

Individuals with Parkinson’s disease (PD) exhibit compromised dynamic postural stability with impaired gait and balance, which contribute to walking limitations. Performing turns while walking perturbs mediolateral stability, challenges the daily functioning of people with PD, and is attributed to altered thoracic movement patterns that include reducing peak turn velocity (°/s). Although previous studies in our lab demonstrated that individuals with neurological impairments improved walking capacity following performance-based overground locomotor training (OLT), dynamic postural stability changes following OLT in people with PD remain unknown. PURPOSE: Characterize changes in dynamic postural stability during turns while walking among individuals with PD following OLT, evidenced by peak turn velocity change. METHODS: Twelve participants with PD (7 Male / 5 Female; Age: 68.5 ± 6.4 years; Hoehn and Yahr: 1-3) completed 24 60-minute OLT sessions twice-weekly. Baseline (PRE) and follow-up (POST) assessments included the 10-minute walk test (10MWT) indoors along a 60-meter corridor while wearing inertial sensors around the fourth lumbar vertebra and the sternum. Angular velocity was collected from each sensor and processed offline. First, turns were identified using integrated lumbar data and extracted from the sternum sensor. Next, peak turn velocity was averaged across all turns at PRE and POST, respectively. Finally, the mean peak turn velocity changes were calculated in the frontal (PTVF) and transverse (PTVT) planes of motion. Positive (+) change reflects improved dynamic postural stability during turns. Statistical analysis included one-tailed t-tests and Cohen’s d effect size. RESULTS: Completed turns increased after OLT (+1.5 ± 1.51; p < 0.01). PTVF showed a moderate and significant increase following OLT (+1.59 ± 2.18 °/s; 95%CI: 0.20, 2.98; p = 0.014; Cohen’s d = 0.43) while PTVT change was small and not significant (+0.88 ± 3.18 °/s; 95%CI: -2.90, 1.14; p = 0.179; Cohen’s d = 0.25). CONCLUSION: This study provides preliminary evidence suggesting that participants moderately improved frontal plane dynamic postural stability during turns after OLT by adapting thoracic movement patterns in ways that likely attenuated perturbed mediolateral stability.