Transcranial sonography in dystonia.

The cause of idiopathic dystonia is not entirely elucidated. In the pathophysiological model of dystonia, the basal ganglia play a major role, mainly putamen, globus pallidus internus, thalamus, and cortex. However, using conventional structural neuroimaging methods, no specific alterations could be detected in this area. Using transcranial sonography (TCS) as a noninvasive, easy to perform, and side-effect-free method, it could be shown that in up to 75% of patients with cervical dystonia (CD), in a high percentage of other focal dystonias, but seldom in facial and genetically determined dystonia, hyperechogenicity of the medial part of the lentiform nuclei (LN) can be visualized in the third ventricular scanning plane. Based on these TCS findings an increased copper content of the LN could be verified in dystonia, opening new perspectives on possible pathophysiological aspects and future research. In clinical routine, this method may be used for early and differential diagnosis of primary dystonia.