| Objective: To compare surface electromyogram (EMG) signals of superficial trunk muscles during the trunk rotating to the left (the paralyzed side) and the right (the non-paralyzed side) between normal individuals and stroke patients with hemiplegia. Methods: Seventeen stroke patients with hemiplegia and 16 healthy volunteers were selected. Root mean square (RMS) of surface EMG signals of rectus abdominis, external oblique abdominal muscle, thoracic erector spinae muscles, lumbar erector spinae muscles and latissimus dorsi were collected from the 2 groups when the trunk rotating 45° to the left (the paralyzed side) and 45° to the right (the non-paralyzed side). Results: When the trunk of normal individuals rotated to one side, RMS value of contralateral external oblique abdominal muscle was higher than that of the rotating side (P<0.01), and RMS values of thoracic erector spinae muscles and latissimus dorsi in the rotating side were higher than those of the opposite side (P<0.01). When stroke patients rotated to the left (the paralyzed side), RMS values of external oblique abdominal muscle, thoracic erector spinae muscles and latissimus dorsi in the side of hemiplegia were lower than those of the left side in the normal group (P<0.01), and RMS value of external oblique abdominal muscle in the non-paralyzed side was lower than that of the normal group in the right side (P<0.01). When stroke patients rotated to the right (the non-paralyzed side), RMS values of external oblique abdominal muscle and thoracic erector spinae muscles in the side of hemiplegia were lower than those of the normal group in the left side (P<0.01), RMS value of lumbar erector spinae muscles in the side of hemiplegia was lower than that of normal group in the left side (P<0.05), and RMS values of external oblique abdominal muscle, thoracic erector spinae muscles and lumbar erector spinae muscles in the non-paralyzed side were lower than those of the normal group in the right side (P<0.01). Conclusion: In normal individuals rotating the trunk, thoracic erector spinae muscles, latissimus dorsi and external oblique abdominal muscle show obvious cross, EMG activities of thoracic erector spinae muscles and latissimus dorsi in the rotating side increase significantly, and EMG activities of external oblique abdominal muscle in the opposite side increase evidently. In stroke patients, no such cross is found. |
