Tai Chi improves non-motor symptoms of Parkinson's disease: One-year randomized controlled study with the investigation of mechanisms

Background: Tai Chi was found to improve motor symptoms in Parkinson's disease (PD). Whether long-term Tai Chi training could improve non-motor symptoms (NMS) and the related mechanisms were unknown. Objective: To investigate Tai Chi's impact on non-motor symptoms in PD and related mechanisms. Methods: 95 early-stage PD patients were recruited and randomly divided into Tai Chi (N = 32), brisk walking (N = 31), and no-exercise groups (N = 32). All subjects were evaluated at baseline, 6 months, and 12 months within one-year intervention. Non-motor symptoms (including cognition, sleep, autonomic symptoms, anxiety/ depression, and quality of life) were investigated by rating scales. fMRI, plasma cytokines and metabolomics, and blood Huntingtin interaction protein 2 (HIP2) mRNA levels were detected to observe changes in brain networks and plasma biomarkers. Results: Sixty-six patients completed the study. Non-motor functions assessed by rating scales, e.g. PD cognitive rating scale (PDCRS) and Epworth Sleepiness scale (ESS), were significantly improved in the Tai Chi group than the control group. Besides, Tai Chi had advantages in improving NMS-Quest and ESS than brisk walking. Improved brain function was seen in the somatomotor network, correlating with improved PDCRS (p = 0.003, respectively). Downregulation of eotaxin and upregulation of BDNF demonstrated a positive correlation with improvement of PDCRS and PDCRS-frontal lobe scores (p <= 0.037). Improvement of energy and immune-related metabolomics (p <= 0.043), and elevation of HIP2 mRNA levels (p = 0.003) were also found associated with the improvement of PDCRS. Conclusions: Tai Chi improved non-motor symptoms in PD, especially in cognition and sleep. Enhanced brain network function, downregulation of inflammation, and enhanced energy metabolism were observed after Tai Chi training.