Treatments of Parkinson disease: circa 2003.

Parkinson disease (PD) is a progressive degenerative neurological disorder characterized by resting tremor, bradykinesia, cogwheel rigidity, and postural instability.1 In the later stages, approximately 25% or more of patients develop cognitive compromise. The cardinal pathological features of PD are degeneration of dopaminergic neurons in the substantia nigra pars compacta and their axons, which project principally to the caudate and putamen, and the presence of eosinophilic intracytoplasmic inclusions, Lewy bodies.2-3 Although the loss of neurons is most conspicuous in the substantia nigra pars compacta, neuronal loss and/or Lewy bodies are found in other brain regions (eg, the locus coeruleus, entorhinal region, and amygdala),2 which suggests that treatments that target only the nigrostriatal dopaminergic system, though they may substantially benefit patients, are unlikely to completely resolve the deficits of PD.