A Longitudinal Electromyography Study of Complex Movements in Poststroke Therapy. 2: Changes in Coordinated Muscle...

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomechanics

Background:

• Fine motor control relies on coordinated muscle group activation, known as muscle synergies.
• Stroke significantly alters muscle synergies, impacting motor deficits.
• Understanding these changes during therapy is crucial for optimizing rehabilitation strategies.

Purpose of the Study:

• To investigate the pattern and longitudinal changes in upper limb muscle synergies during therapy in stroke patients.
• To correlate muscle synergy characteristics with motor function levels.
• To assess the impact of Wii-based Movement Therapy (WMT) on muscle activation patterns.

Main Methods:

• Electromyography (EMG) was recorded from 6 upper limb muscles in 24 stroke patients during WMT.
• Non-negative matrix factorization (NMF) analyzed EMG data to extract muscle synergies.
• Clinical assessments (WMFT, FMA, MAL) evaluated motor function pre-, post-therapy, and at 6-month follow-up.

Main Results:

• All patients showed improved motor function post-therapy and sustained improvements at follow-up.
• Fewer muscle synergies were observed in patients with low motor function compared to high motor function at early therapy.
• Increased number of synergies and changes within synergies by late therapy indicated improved motor control and movement quality.

Conclusions:

• Stroke patients with lower motor function exhibit less complex muscle activation patterns.
• Wii-based Movement Therapy promotes increased muscle synergy complexity and distinctness, correlating with improved motor function.
• Muscle synergy analysis provides insights into motor recovery post-stroke and can inform therapeutic interventions.