Investigating the Optimal Assistive Strategy for Freezing of Gait: A Comparison of Unilateral and Bilateral Artificial Muscle Assistance

As the global population continues to age, the number of individuals with Parkinson’s disease (PD) is pro- jected to increase significantly. Freezing of Gait (FoG), a common motor symptom in PD, affects more than half of patients and becomes more prevalent with disease progression. Suppression of FoG is essential for improving quality of life (QoL), and various assistive strategies have been proposed. This study evaluates the effectiveness of unilateral versus bilateral assistance using the Unplugged Suit for PD Patients (UPS-PD), a wearable gait assistive device powered by pneumatic artificial muscles. While prior UPS-PD studies examined only unilateral assist, bilateral assist has not been comparatively investigated. A slalom walking experiment was conducted as a single-case study with one PD participant under both assist conditions. The results indicated that bilateral assist produced more favorable gait patterns, including reduced gait asymmetry, increased swing duration, lower %DLS, and smaller variability, compared with unilateral assist. These improvements were supported by medium-to-large effect sizes in key parameters. Although generalization is limited due to the single-case design, these findings provide preliminary insights into assistive strategies for FoG suppression. Future studies involving larger and more diverse cohorts are required to validate these results.