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Published on: June 12, 2019
A new EMG-based index towards the assessment of elbow spasticity for post-stroke patients
Abstract:
The commonly used method for grading spasticity in clinical applications is Modified Ashworth Scale (MAS). The MAS-based method depends on the subjective evaluations and the experience of physicians, which may lead to imprecise and inconsistent evaluations. In this study, we propose a novel index (A-ApA, which was calculated with the root mean square (RMS) of agonist muscle activity by the mean between the RMS of agonistic and antagonistic muscle activations extracted from surface electromyography (sEMG) signals to quantitatively assess elbow spasticity. 39 post-stroke patients with elbow spasticity caused by hemiplegia participated in the experiments, and their elbow spasticity was assessed with MAS by one experienced physiotherapist. Patients were thereafter divided into four groups according to the MAS scales. The sEMG signals were recorded simultaneously on the patients' biceps and triceps when they extended or bended their elbows passively. The correlations between MAS and RMS of sEMG signals as well as the newly proposed index were calculated. The results demonstrated that the correlation between the MAS and the sEMG-based index in the assessment of elbow spasticity was significant. This suggests that the EMG-based index would be helpful for the assessment of spasticity..
Insights
A new surface electromyography (sEMG) index quantifies elbow spasticity in stroke patients. This objective measure shows significant correlation with the subjective Modified Ashworth Scale (MAS), offering a more consistent spasticity assessment.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Rehabilitation Medicine
Background:
- The Modified Ashworth Scale (MAS) is the standard for grading spasticity but relies on subjective physician assessments, leading to variability.
- Objective and consistent methods are needed for accurate spasticity evaluation in clinical settings.
Purpose of the Study:
- To introduce and validate a novel quantitative index, A-ApA, derived from surface electromyography (sEMG) signals for assessing elbow spasticity.
- To compare the proposed sEMG-based index with the established MAS for elbow spasticity in post-stroke patients.
Main Methods:
- Collected sEMG data from biceps and triceps during passive elbow movements in 39 hemiplegic stroke patients.
- Calculated the A-ApA index using the root mean square (RMS) of agonist muscle activity relative to mean agonist and antagonist muscle activations.
- Correlated the A-ApA index and sEMG RMS values with MAS scores assigned by an experienced physiotherapist.
Main Results:
- A significant correlation was found between the novel sEMG-based index (A-ApA) and the MAS scores for elbow spasticity.
- The study demonstrated the potential of sEMG-derived metrics for objective spasticity assessment.
Conclusions:
- The proposed A-ApA index offers a promising, quantitative approach to supplement or potentially replace subjective MAS evaluations for elbow spasticity.
- This sEMG-based method could improve the consistency and precision of spasticity assessment in stroke rehabilitation.
