[Transcranial sonography in Parkinson's disease].

An abnormal hyperechogenecity of substantia nigra is thought to be the most characteristic sonographic feature in Parkinson's disease (PD). However specificity and sensitivity of the ultrasound method should be refined. Using transcranial sonography, authors have examined 168 patients with different clinical signs of parkinsonism, including 99 patients with idiopathic PD, and 56 patients without extrapyramidal disorders. Hyperechogenecity of substantia nigra was found in 93% of patients and in 14% of controls. It has been shown that this biomarker can successfully discriminate PD from a number of similar disorders (essential tremor, atypical parkinsonian syndromes). Sonographic features of late, early and genetically determined parkinsonism specifying some pathogenetic aspects of these pathologies are described. Taking into account the data obtained, transcranial sonography can be considered as a highly informative method in the differential and early diagnosis of PD.