Summary

The nonmotor symptoms (NMS) of Parkinson's disease (PD) are common and occur across all stages of disease. Often underreported and a key determinant of quality of life, they can occur in conjunction with nonmotor fluctuations (dysautonomic, cognitive/psychiatric, and sensory/pain). NMS in PD may be associated with dopamine deficiency due to degeneration of the substantia nigra, but they may have a nondopaminergic origin as well. This article discusses several of the PD-related NMS, management strategies for patients with PD with nondopaminergic NMS, and the emerging use of animal models to improve treatment of PD-related NMS and learn about early-onset NMS.