Brief History & Introduction of Parkinson's disease

Several early sources, including an Egyptian papyrus, an Ayurvedic medical treatise, the Bible, and Galen's writings, describe symptoms resembling those of PD. After Galen there are no references unambiguously related to PD until the 17th century. In the 17th and 18th centuries, several authors wrote about elements of the disease, including Sylvius, Gaubius, Hunter and Chomel.

In 1817 an English doctor, James Parkinson, published his essay reporting six cases of paralysis agitans. An Essay on the Shaking Palsy described the characteristic resting tremor, abnormal posture and gait, paralysis and diminished muscle strength, and the way that the disease progresses over time. Early neurologists who made further additions to the knowledge of the disease include Trousseau, Gowers, Kinnier Wilson and Erb, and most notably Jean-Martin Charcot, whose studies between 1868 and 1881 were a landmark in the understanding of the disease. Among other advances, he made the distinction between rigidity, weakness and bradykinesia. He also championed the renaming of the disease in honor of James Parkinson.

In 1912 Frederic Lewy described microscopic particles in affected brains, later named "Lewy bodies". In 1919 Konstantin Tretiakoff reported that the substantia nigra was the main cerebral structure affected, but this finding was not widely accepted until it was confirmed by further studies published by Rolf Hassler in 1938. The underlying biochemical changes in the brain were identified in the 1950s, due largely to the work of Arvid Carlsson on the neurotransmitter dopamine and its role on PD. In 1997, alpha-synuclein was found to be the main component of Lewy bodies.

Anticholinergics and surgery (lesioning of the corticospinal pathway or some of the basal ganglia structures) were the only treatments until the arrival of levodopa, which reduced their use dramatically. Levodopa was first synthesized in 1911 by Casimir Funk, but it received little attention until the mid 20th century. It entered clinical practice in 1967 and brought about a revolution in the management of PD. By the late 1980s deep brain stimulation emerged as a possible treatment.