Evaluating Hand Motor Coordination of Chronic Stroke Survivors Through the Combination of Features Extracted From a High-density EMG Sleeve 4361

Abstract

Objectives

To investigate whether hand motor coordination of stroke survivors can be explained through a combination of features extracted from a high-density electromyography (HD-EMG) sleeve.

Design

Standardized clinical assessments were evaluated in participants with stroke and scored by a licensed occupational therapist. Assessments included the upper extremity section of the Fugl-Meyer and the Modified Ashworth Scale test to assess finger and wrist spasticity. After clinical assessments, subjects performed 12 functional hand and wrist movements while HD-EMG was recorded using a wearable sleeve. Movements were visually evaluated based on an observed movement score (0=no movement, 1=visible movement, 2=incomplete movement, and 3=normal movement). After data collection, a variety of HD-EMG features, or views, were calculated from EMG, namely cocontraction, muscle correlation, muscle synergies, and motor unit firing coherence.

Setting

This study was performed at Battelle Memorial Institute.

Participants

This study enrolled able-bodied adults (n=7) and chronic stroke subjects with upper limb hemiparesis (n=7). Participants with stroke had hand impairment that interferes with their ability to perform activities of daily living and were classified as stage 1-6 on the hand subscale of the Chedoke McMaster Stroke assessment.

Interventions

Not applicable.

Main Outcome Measures

Main outcome measures include the correlation of HD-EMG features, or a combination of features, with the upper extremity section of the Fugl-Meyer and Modified Ashworth Scale scores.

Results

Stroke subjects had higher cocontraction and reduced muscle coupling when attempting to open their hand and actuate their thumb. Muscle synergies decomposed in the stroke population were relatively preserved. Alterations in synergy composition demonstrated reduced coupling between digit extensors and muscles that actuate the thumb, as well as an increase in flexor activity in the stroke group. Average synergy activations during movements revealed differences in coordination, highlighting overactivation of antagonist muscles and compensatory strategies. Motor units decomposed in the stroke population had a lower firing coherence across movements, demonstrating reduced neural drive to muscles. When combining features using canonical correlation analysis, the first latent component was correlated with upper extremity section of the Fugl-Meyer hand subscore (R²=0.85). Latent component weightings revealed interpretable measures of motor coordination and muscle coupling alterations.

Conclusions

These results demonstrate the feasibility of predicting motor function through features decomposed from a wearable HD-EMG sleeve, which could be leveraged to improve stroke research and clinical care. Disclaimer: This device has not been approved or cleared as safe or effective by US Food and Drug Administration. This device is limited by US federal law to investigational use.

Disclosures

All authors are employees of Battelle Memorial Institute, which has developed the NeuroLife Sleeve.