Parkinson's Disease.

The diagnosis of Parkinson disease (PD) is based on the presence of bradykinesia and either resting tremor or rigidity and there should be no features from the history or examination to suggest an alternative cause of parkinsonism. In addition to the motor manifestations of PD, there is a long list of nonmotor symptoms, several of which occur before motor signs and are considered "prodromal" PD. These are classified as neuropsychiatric, autonomic, sleep, and sensory. There are many medical options for the treatment of PD but levodopa remains the mainstay. Deep brain stimulation and other advanced therapies are also available.