Diagnosis and epidemiology of Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. The last 5 years have been marked by rapid developments in understanding the pathophysiology of PD as well as by the introduction of a number of new drugs for symptomatic treatment of the disease. On the other hand, the diagnosis of PD is still made purely on clinical grounds. Due to continuing advances in therapy, it is increasingly important to recognize PD in its earliest stages and to distinguish it from other causes of parkinsonism, for which prognosis and response to treatment differ. This article reviews the epidemiology of PD and then elaborates on the diagnosis and differential diagnosis.