Non-motor symptoms of Parkinson's disease in China: a review of the literature.

Parkinson's disease (PD) is generally considered as a neurodegenerative disorder commonly characterized by bradykinesia, resting tremor, rigidity and postural instability. However, increasing evidence demonstrates that serial non-motor symptoms (NMSs), including sensory symptoms, dysautonomia, neurobehavioral disorders and sleep disturbances frequently occur prior to motor signs and invariably emerge with the disease progression. Compared with motor symptoms, the NMSs are frequently under-recognized and poorly managed in clinical practice. A growing number of clinical studies on NMSs of PD have been carried out in China over the past decade. They revealed that there were not only common features, but also some differences on NMSs between Chinese patients and those in the West. Meanwhile, pharmacological and non-pharmacological strategies are available for the treatment of some NMSs associated with PD in China contained in Chinese guidelines for the treatment of PD. Large cohort studies across the country are warranted in the future to explore the epidemiological and biological features of specific NMSs in Chinese PD patients.