Responsiveness and Change in Functional Mobility Measures According to Ankle Plantar Flexor Spasticity Severity in...

Ankle plantar flexor spasticity is a common post-stroke impairment that may influence functional performance and responsiveness. However, descriptive responsiveness patterns across spasticity severity levels remain insufficiently explored. This study aimed to descriptively examine functional changes and responsiveness across ankle plantar flexor spasticity severity categories in individuals with subacute stroke.

In this prospective observational cohort study with a 4-week follow-up, 58 participants were categorized based on ankle plantar flexor spasticity severity using Modified Ashworth Scale (MAS) scores (MAS = 0, MAS = 1-1⁺, and MAS ≥ 2). Functional performance was assessed using the 10-M Walk Test (10 mWT), 6-Minute Walk Test (6 MWT), Timed Up and Go (TUG), 5-Times Sit-to-Stand Test (5-Times STS), Figure-of-8 Walk Test (F8WT), and Four Square Step Test (FSST) at baseline and after 4 weeks. Responsiveness was quantified using effect size (ES) and standardized response mean (SRM), and subgroup findings were descriptively examined across MAS categories.

All outcome measures showed changes over 4 weeks, with moderate-to-large responsiveness observed across tests. Responsiveness estimates appeared numerically greater in the MAS = 0 subgroup, whereas more variable estimates were observed in participants with spasticity (MAS ≥ 1). Similar patterns were observed across gait-related and functional mobility measures.

Responsiveness estimates varied across spasticity levels, suggesting that responsiveness, as a measurement property, may differ according to impairment severity. These findings provide preliminary descriptive information regarding responsiveness across spasticity severity categories. Given the exploratory design and descriptive subgroup analyses, the findings should be interpreted cautiously.