From the Neuropharmacology Unit, Defense and Veteran Head Injury Program, Henry M. Jackson Foundation, and National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Md.
Edited by Thomas C. Jefferson, MD, JAMA Fishbein Fellow.
Parkinsonian syndromes can be classified into 2 major groups: Parkinson
disease (PD) and atypical parkinsonian disorders. Common characteristics include
akinesia, expressed as slowness and paucity of movement (eg, decreased arm
swing or facial expression) and difficulty in initiating movement, and are
associated with rigidity with or without resting tremor. Parkinsonian syndromes
frequently occur in the elderly, their prevalence increasing markedly with
age (14.9% at the age of 65 to 74 years; 52.4% at the age of 85 years or older).1 The most common parkinsonian syndrome, PD affects
approximately one half million Americans. The incidence of PD is about 10
times that of atypical parkinsonian disorders.2,3
Litvan I. Parkinsonian FeaturesWhen Are They Parkinson Disease?. JAMA. 1998;280(19):1654-1655. doi:10.1001/jama.280.19.1654