Background: Subsequent to spasticity, which is a positive impairment of stroke, neural and mechanical changes often occur in paretic muscles, affecting muscle function. The aim of this study was to find more accurate indices, which could affect decisions about spasticity treatment by investigating the relationship among neural, mechanical, functional outcomes, and clinical parameters in spastic chronic stroke patients.
Methods: In this cross sectional study, 45 spastic chronic stroke patients were included. Clinical assessments, such as spasticity evaluation, were conducted, using the Modified Modified Ashworth Scale (MMAS). Neural properties including H-reflex latency and Hmax / Mmax ratio were acquired. Also, mechanical properties including fascicle length, pennation angle, and thickness of spastic medial gastrocnemius muscle were evaluated. Functional outcomes were evaluated through Timed Up and Go (TUG) test and Timed 10-Meter Walk Test (10-m WTT). Spearman's rank correlation analysis in SPSS version 22.0 was used to find correlations between parameters.
Results: There was a low negative correlation between MMAS and H-reflex latency (r= -0.320, p = 0.032). MMAS score had a low significant relationship with pennation angle (r=0.296, p= 0.049) and thickness of muscles (r=0.389, p=0.008). However, there was no significant correlation between MMAS and functional outcomes.
Conclusion: Based on these findings, MMAS can partly identify changes in neural and mechanical properties of spastic muscles.