Nosography of Parkinson's disease

Mean-age of onset of Parkinson's disease is 56 years. The older the patient is the more rapid is on average the progression of disability. In the early phase the motor symptoms respond well to therapy. Later, variations of response to therapy and side-effects of therapy occur (wearing-off, end-of-dose akinesia, end-of-dose dystonia, dopaminergic abnormal involuntary movements, pharmacogenic psychoses etc.). Due to the modern pharmacologic treatment of Parkinson's disease with dopaminergic substances disabling stages of the disease occur mean 3 to 5 years later than before levodopa-substitution was initiated. The incidence of depression, distinct cognitive deficits (impairment of memory, visuospatial deficits) and dementia increases in the course of the disease. The tremulous form of Parkinson's disease generally leads to less motor impairment than the rigid-akinetic form. Parkinson's disease of early onset (onset before the age of 40), may be regarded as a subtype of Parkinson's disease. Benign and malignant types of Parkinson's disease may be distinguished, as well as overlaps with multisystem atrophies.