The characteristics of trunk muscle activity in patients with Parkinson′s disease

Abstract

Objective To explore the characteristics of trunk muscle activity in persons with Parkinson′s disease (PD) in search of better treatments for abnormal posture. Methods Ninety persons with PD of different severity and 8 normal controls were studied using surface electromyography (sEMG). A sixteen-lead sEMG instrument was used to collect sEMG amplitudes from the bilateral thoracic erector spinae, lumbar erector spinae, external oblique and rectus abdominis muscles when the subjects were lying, standing and walking. Results Compared with the control group, a significant increase was observed in the sEMG amplitude of the lumbar erector spinal muscle [(18.56±14.57)μV] and rectus abdominis muscles [(24.00±18.80)μV] of the PD group when lying. Significant relative increases in (P<0.05), of the external oblique muscles were observed [(27.87±11.49)μV] when standing (P<0.05), and in the thoracic erector spinae muscle [(58.74±29.69)μV] and external oblique muscles [(59.01±25.20)μV] increased when walking (P<0.05). Compared with the control group, the sEMG activity of the external oblique muscles was significantly elevated in PD patients at Hoehn and Yahr stage 1 to 1.5 when walking. One or more of the trunk muscle groups showed significantly greater activity in the PD patients in Hoehn and Yahr stage 2 or 3 in all three positions. Conclusions The sEMG activities of the extensor and flexor muscles increase simultaneously in PD patients. More trunk muscles are involved in PD patients with higher H-Y grades. These findings provide a neurophysiological basis for the customizaton of rehabilitation therapy for patients with Parkinson′s disease and for the precise selection of muscles for botulinum toxin injection. Key words: Parkinson′s disease; Trunk muscles; Surface electromyography