Clinical manifestations of Parkinson's disease.

Although the clinical manifestations of PD remain similar to those described by Parkinson in the nineteenth century, knowledge of associated findings has increased dramatically. The ability to characterize the myriad of findings associated with PD enables clinicians to care better for patients with PD. Knowledge of the associated symptoms as well as the cardinal manifestations allows clinicians to target treatment to specific symptoms and thereby improve the quality of life of those affected with PD.