Parkinson's disease: epidemiology, (differential) diagnosis, therapy, relation to dementia.

Parkinson's disease is a neurodegenerative progressive disorder with a prevalence of 1% in the population above 65 years of age. Thus, Parkinson's disease (PD) is 5 times less common than senile dementia of the Alzheimer type (SDAT). This article summarizes an epidemoliogical door to door survey on the prevalence of Parkinson syndromes in two German villages. It reviews the present possibilities to diagnose Parkinson's disease clinically and with pharmacological and imaging techniques. As 10-30% of Parkinson's disease patients become demented in the course of the disease, the question is addressed, how Parkinson's disease relates to SDAT. In addition, it is discussed, whether a global or focal deficit of cognitive function is present in Parkinson's disease. Finally, a new imaging technique based on the visualisation of dopamine uptake sites in the striatum by single photon computed emission tomography is presented. This technique may allow to diagnose Parkinson's disease in the very early clinical and may be even preclinical phase.