Department of Neurology;
the First Affiliated Hospital of Xi'an Jiaotong University;
Xi'an 710061;
Shaanxi Province;
China;
Department of Neurology;
Xi'an Third Hospital;
Xi'an 710021;
Shaanxi Province;
China;
Department ofNeurology;
the Shaanxi Sengong Hospital;
Xi'an 710300;
Shaanxi Province;
China;
Department of Rehabilitation Medicine;
the First Affiliated Hospital of Xi'an Jiaotong University;
Xi'an 710061;
Shaanxi Province;
China;
Parkinson’s disease; Non-motor symptoms; Constipation; Clinical characteristics; Quality of life; Depression;