Many Faces of Parkinson's Disease: Non-Motor Symptoms of Parkinson's Disease

Parkinson's disease (PD) is a multi-systemic disorder that is characterized by a combination of motor and non-motor symptoms (NMS). The dopaminergic neurodegeneration of PD is involved in the genesis of NMS, but other conditions and side effects of levodopa are also associated with NMS. NMS can develop at all stage of PD and rapid eyeball movement sleep behavior disorder (RBD), constipation, depression, and olfactory dysfunction are considered prodromal signs of PD. Many NMS related with motor deficits and cognitive dysfunction. Some NMS including olfactory dysfunction, RBD and abnormal stereopsis are associated with presence of other NMS of PD. In addition, several NMS can be helpful to differentiate between idiopathic PD and other parkinsonian disorders. Early recognition and management of NMS in PD patients is important for preserving quality of life.