The natural history of Parkinson's disease in the pre-levodopa and post-levodopa eras

Since Parkinson's disease was first described by James Parkinson in 1817, the natural history has been confounded by various treatment modalities: the replenishment of deficient dopamine, the addition of the dopamine agonists, and the more recent addition of drugs whose putative action may slow the natural history of the disease. Nevertheless it remains a disease that is slowly and inexorably progressive over several decades. The quality of life during this progression can be improved, and the duration of life before inanition produces life-threatening complications can be extended. New approaches to identifying the disease before the overt symptoms appear and to slowing the progression of the underlying pathophysiology are being explored but to date have not produced significant changes in the prognosis for the individual patient.