Symptomatic dystonias associated with structural brain lesions: report of 16 cases.

BACKGROUND Symptomatic (secondary) dystonias associated isolated lesions in the brain provide insight into etiopathogenesis of the idiopathic form of dystonia and are a basis for establishing the possible correlation between the anatomy of a lesion and the type of dystonia according to muscles affected. METHODS In 358 patients with differently distributed dystonias, a group of 16 patients (4.5%) was encountered in whom dystonia was associated with focal brain lesions. RESULTS Of the 16 patients, 3 patients had generalized, 3 segmental and 4 hemidystonia, while the remaining 6 patients had focal dystonia. The most frequent etiologies were infarction in 7, and tumor in 4 patients. These lesions were usually found in the lenticular and caudate nucleus, thalamus, and in the case of blepharospasm in the upper brainstem. CONCLUSIONS Our results support the suggestion that dystonia is caused by a dysfunction of the basal ganglia.