Parkinson's disease is a progressive neurodegenerative disorder with prominent motor features. The cardinal motor signs, bradykinesia, rigidity, and tremor, are treated effectively by dopaminergic therapies. Levodopa is standard, and often initial, therapy for patients with this condition. However, with continued treatment, and as the disease progresses, the response to oral dopaminergic drugs becomes unstable and motor fluctuations emerge, including off periods (when medication effects wear off) and dyskinesia (dystonic or choreatic movements) (Slide 1). Risk factors for motor complications include younger age at disease onset, longer disease duration, higher levodopa dosage, and more severe motor symptoms.