Clinical Research Directory

Inclusion Criteria: 1. aged 40-70 years; 2. had a PD diagnosis designated by movement disorder neurologists (Ke-zhong Zhang and Yong-sheng Yuan) according to Movement Disorder Society Clinical Diagnostic Criteria; 3. fulfilled Rome IV criteria for functional constipation, including having \< 3 spontaneous bowel movements (SBM; i.e., not induced by rescue medication) per week for the past 3 months with symptom duration of at least 6 months; 4. stable initiation of PD medications, leastways 3 month before this investigation; (5) provided written informed consent. Exclusion Criteria: 1. a history of previous abdominal surgery (other than appendectomy); 2. the presence of carcinoma; 3. any organic diseases causing constipation or neurologic diseases such as multiple sclerosis, rachischisis, or spinal cord injury; 4. taking antidepressant agents including tricyclic antidepressants and selective serotonin reuptake inhibitors; 5. a serious concomitant disease of the heart, liver, kidney, or diabetes; 6. pregnancy or lactation; 7. participating in another trial or enrolled in a trial during the past month; 8. an allergic reaction to surface electrodes.