Parkinson’s disease is a chronic, progressive, and debilitating neurodegenerative disorder that affects approximately one million people in the United States and six million people worldwide. Parkinson’s disease is caused by low dopamine levels produced in the brain. Dopamine helps transmit signals between the areas of the brain that control all purposeful movements, including talking, walking, and writing. As Parkinson’s disease progresses, dopamine production steadily decreases, resulting in increased problems with motor symptoms including slowed movement (bradykinesia), tremor, rigidity, impaired posture and balance, and difficulty with speech and writing.
There is presently no cure for Parkinson’s disease and management of the disease consists of the use of treatments that attempt to control motor symptoms primarily through dopaminergic mechanisms. The current gold standard for treatment of motor symptoms is levodopa/carbidopa. While levodopa/carbidopa improves patients’ motor symptoms, as the disease progresses, the beneficial effects of levodopa begin to wear off more quickly. Patients then experience motor fluctuations throughout the day between “on” time, periods when the medication is working and Parkinson’s disease symptoms are controlled, and “off” time, when the medication is not working and motor symptoms return.