[Differential diagnosis in parkinsonism].

Parkinsonism is an important cause of disability in elderly people. Parkinsonian syndromes fall into one of three major categories: Parkinson's disease, secondary (symptomatic) parkinsonism and parkinsonian syndromes occurring as one of the major manifestations of several neuronal system degenerations. Clinical differential diagnosis of parkinsonism may be difficult and studies, which correlate clinically diagnosed Parkinson's disease and the neuropathological findings in the same patients, have shown that 20-30% of these patients had another disease. The prognosis and treatment are different for parkinsonian syndromes and Parkinson's disease, and an accurate clinical diagnosis is thus important, both for research and for management of individual patients. The present article reviews some of the aspects of differential diagnosis of parkinsonism and gives guidelines as to practical diagnostic work with these patients. A new approach to diagnosis in Parkinson's disease is presented. The article also discusses the possible role of new diagnostic tools like imaging techniques and neurophysiological methods in the diagnosis of parkinsonism.