The impact of brain network microstructural changes on upper limb mirror movements after stroke

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Medical Imaging

Background:

• Mirror movements (MMs) are involuntary movements observed in stroke patients.
• Upper limb MMs can indicate impaired motor control after stroke.
• The relationship between brain microstructural changes and MMs requires further investigation.

Purpose of the Study:

• To investigate the association between brain network microstructural changes and surface electromyographic (sEMG) signs of upper limb MMs in stroke patients.
• To explore the role of the corpus callosum and corticospinal tracts (CSTs) in post-stroke MMs.

Main Methods:

• Retrospective analysis of 48 stroke patients.
• Utilized surface electromyography (sEMG) to quantify MMs (overflow percentage, standardized net excitation).
• Employed diffusion tensor imaging (DTI) to analyze microstructural integrity (FA, MD, AD, RD) of the corpus callosum and bilateral CSTs.

Main Results:

• Significant asymmetry in motor overflow was observed between affected and unaffected limbs.
• Patients with right-sided cerebral infarction (RCI) showed more pronounced MMs than left-sided cerebral infarction (LCI) patients.
• In the LCI group, reduced fractional anisotropy (FA) in the corpus callosum and CSTs correlated with increased MMs.

Conclusions:

• sEMG-detected MMs can serve as an indicator of upper limb motor function in stroke survivors.
• Microstructural changes in the corpus callosum and CSTs are potential contributors to post-stroke MMs.
• These findings highlight the neural basis of MMs and their implications for stroke rehabilitation.