Multidirectional Trunk Movements Reveal Hidden Symmetry Loss in Stroke: An Electromyography-Based Comparative Study

Area of Science:

• Neurology
• Rehabilitation Science
• Biomechanics

Background:

• Stroke and hemiplegia cause asymmetrical muscle activation, impairing trunk control and movement.
• Understanding trunk muscle symmetry is crucial for effective stroke rehabilitation strategies.

Purpose of the Study:

• To compare trunk muscle activation symmetry between healthy adults and stroke patients across various functional tasks.
• To identify movement-specific patterns of asymmetry in different groups.

Main Methods:

• A comparative cross-sectional study involving healthy adults and stroke patients.
• Analysis of rectus abdominis, external oblique, internal oblique, and multifidus symmetry during trunk flexion, extension, and lateral flexion.
• Two-way repeated measures ANOVA to examine group, condition, and muscle effects.

Main Results:

• Trunk muscle symmetry is significantly influenced by movement conditions, with differing patterns between healthy individuals and stroke survivors.
• Lateral flexion demonstrated the most significant asymmetry, with distinct responses in the two groups.
• Condition-dependent variations in symmetry were observed, particularly between abdominal and deep spinal muscles.

Conclusions:

• Trunk muscle symmetry is dynamic and condition-dependent, varying significantly between healthy adults and stroke patients.
• Rehabilitation interventions for stroke survivors should prioritize movement-specific demands and dynamic symmetry over isolated muscle training.
• Optimizing functional recovery in stroke requires addressing the complex interplay of trunk muscles during functional movements.