MRI morphometry in primary focal dystonia

Abstract

Primary blepharospasm (BS) is one of most frequent forms offocal dystonia characterized by excessive involuntary eye closure.Pathophysiology of primary BS remains obscure. The purposeof this study: to determine changes of the cerebral gray mattervolume that may be pathogenically important in primary BS.We examined 23 right-handed patients with primary BS (6 malesand 17 females) and 16 healthy age- and sex-matched individualswho underwent voxel-based morphometry (VOM) amethod of assessment of fine regional quantitative changes ofgray matter volume. In 15 patients VOM studies were performedtwice, before and one month after injections of botulinum toxintype A (BTA). Compared to controls, BS patients were characterizedby the decrease in gray matter volume in the head of theright caudate nucleus, anterior and posterior lobes of the rightcerebellar hemisphere, and the right fusiform gurus. Multiplefactoranalysis did not show relationships between gray matterchanges and age of patients, age at the debut of BS, and durationof the disease or BTA treatment. On repeat examination afterlocal BTA injections in the circular orbicular muscles (aimed atreducing dystonic spasms in BS patients), the increase in graymatter volume in both fusiform gyri, the opercular parts of theleft Rolandic gyrus, the right middle and the left inferior temporalgyri, the left inferior frontal gyrus, and the left cingular gyruswas observed. The obtained data demonstrate the presence ofstructural brain changes in primary BS, confirming a significantrole of the striatum and the cerebellum in pathophysiology ofthis form of focal dystonia.

Keywords

• focal dystonia
• blepharospasm
• voxel-based morphometry
• botulinim toxin type a