Advanced strategies for treatment of Parkinson's disease: the role of early treatment.

Parkinson's disease (PD) is associated with significant patient disability and costs to the healthcare system. It is questioned whether early treatment may improve outcomes and delay disability. Early treatment relies on early diagnosis, which can be difficult to achieve because the diagnosis of PD is based on motor symptoms, is clinical in nature, and is complicated by potential presentation of nonmotor symptoms prior to motor symptoms. Economic analyses demonstrate that treatments other than levodopa may be cost-effective. The lack of correlation between Unified PD Rating Scale (UPDRS) outcomes and imaging studies of dopamine uptake may reflect the inappropriate selection of study end points, since activities of daily living scores may be more applicable than motor function scores. Levodopa, the standard therapy for motor control of PD and one of the most effective options, is associated with complications (a wearing-off effect) when used long term. Other therapies, including dopamine agonists and monoamine oxidase type-B (MAO-B) inhibitors, may limit the rate of dyskinesia relative to levodopa-based regimens. It appears that early treatment with the MAO-B inhibitor rasagiline (1 mg), as compared with late treatment, delays the onset of worsened UPDRS score, especially the nonmotor activities of daily living subscore.