Abstract: Objective To explore the characteristics of surface electromyogram (sEMG) of the forearm muscles of Parkinson's disease patients with or without load. Methods 26 Parkinson's disease patients and 28 healthy individuals participated in this study. All the subjects performed isometric contraction for elbow flexion without load or with a load of 1.5 kg. The sEMG signals were collected by surface electrodes and processed by linear time and frequency domain method. Results The values of median frequency (MF) and mean power frequency (MPF) were higher in the patients than in the healthy controls without load (P<0.05). The value of average EMG (AEMG) was lower in the patients than in the healthy controls with a load of 1.5 kg (P<0.001). For the patients, the values of MF and MPF were higher without load than with a load of 1.5 kg (P<0.001), and the value of AEMG was er without load than with a load of 1.5 kg (P<0.001). For the healthy controls, only the value of AEMG was lower without load than with a load of 1.5 kg (P<0.001). Conclusion The values of MF and MPF are higher in Parkinson's disease patients than in the healthy controls without load while the value of AEMG is lower in Parkinson's disease patients than in the healthy controls with load.

Key words: Parkinson's disease, surface electromyogram signals, forearm muscles, loading, static tremors