Lenticular nucleus lesion in idiopathic dystonia detected by transcranial sonography

We report the transcranial sonography (TCS) findings of the basal ganglia in 86 patients with dystonic disorders including idiopathic dystonia (facial, cervical, upper limb, and generalized dystonia), drug-induced tardive dystonia, dopa-responsive dystonia, and kinesigenic dystonia. The TCS was focused on alterations of the lenticular, caudate, raphe nuclei, and the thalamus. Seventy-five percent of patient with idiopathic cervical and 83% of those with idiopathic upper limb dystonia had a hyperechogenic lesion of the middle segment of the lenticular nucleus on the side opposite to the clinical dystonic symptoms. The ipsilateral side was also affected in 20%. In facial dystonia, only one-third of the patients revealed lenticular nucleus lesions. The mean area of the lenticular nucleus lesion opposite to the clinically affected side was 30 mm2 in cervical dystonia, 17 mm2 in upper limb dystonia, and 7.5 mm2 in facial dystonia. These lenticular abnormalities were significantly more frequent (p < 0.001) and their areas were significantly greater (p < 0.001) compared with a control group of 50 patients afflicted with radiculopathy. There was a significant correlation of the severity of symptoms with the intensity of lenticular nucleus hyperechogenicity in patients with cervical and upper limb dystonia (p < 0.05). Increased caudate nucleus echogenicity was present in 20% of patients with cervical and upper limb dystonia, mostly contralateral to the clinically affected side and raphe abnormalities were present in 7% of all patients with idiopathic dystonia. In contrast, there were no abnormalities of the lenticular nucleus or thalamus in nonidiopathic dystonias. We conclude that idiopathic dystonia is associated with lesions in the basal ganglia, particularly the lenticular nucleus, that can be visualized by TCS. An alteration of the basal ganglia matrix may be the pathologic basis of idiopathic dystonia with secondary affliction of striatopallidothalamic pathways.