The role of surface electromyography in the assessment of myotonia in Parkinson's disease

Abstract

Objective To analyze the relationship between biceps, triceps surface integrated electromyography (iEMG) recorded by surface electromyography (sEMG) and the degree of myotonia in patients with Parkinson's disease (PD), and to explore the feasibility of iEMG value as an objective quantitative index of the degree of myotonia in patients with PD. Methods A total of 51 patients with PD who were admitted to The First Affiliated Hospital of Anhui Medical University from September 2022 to November 2023 were included, as well as 19 healthy controls matched by sex and age. The motor symptoms and myotonic degree of the subjects were evaluated by Unified Parkinson's Disease Rating Scale Ⅲ (UPDRS Ⅲ). sEMG was used to collect the sEMG signals of the biceps and triceps of the subjects during passive upper limb movement, and the iEMG value was calculated. A total of 32 patients with PD were randomly selected for Levodopa Shock Test. iEMG values and UPDRSⅢ myotonic scores of upper limbs were collected before and after the test. Spearman rank correlation analysis was used to analyze the correlation between iEMG values and UPDRSⅢ myotonic scores of upper limbs. Results In PD group, the iEMG values of biceps muscle (Z = ‑ 4.874, P = 0.000) and triceps muscle (Z = ‑ 4.880, P = 0.000) of more severe symptoms side were higher than those of less severe symptoms side. Spearman rank correlation analysis showed that myotonic scores of upper limbs (0-3 points) in PD group was positively correlated with biceps (rs = 0.735, P = 0.000) and triceps (rs = 0.545, P = 0.000) iEMG values. The iEMG values of muscles with myotonia score of 1 (biceps Z = 5.344, P = 0.000; triceps Z = 5.146, P = 0.000), 2 (biceps Z = 7.421, P = 0.000; triceps Z = 6.891, P = 0.000), 3 (biceps Z = 5.340, P = 0.000; triceps Z = 5.145, P = 0.000) in PD group were higher than those in control group. In addition, before levodopa impact (biceps rs = 0.664, P = 0.000; triceps rs = 0.386, P = 0.029) and after impact (biceps rs = 0.620, P = 0.000; triceps rs = 0.588, P = 0.000) in PD group, there was a positive correlation between myotonic scores of upper limbs and iEMG values. Conclusions The iEMG values of biceps and triceps can reflect the severity of myotonia in PD patients, and can be used as a quantitative evaluation index of myotonia in PD patients.

DOI: 10.3969/j.issn.1672‑6731.2024.03.008