Brain Structural Changes In Primary Focal Dystonia (P2.045)

OBJECTIVE: To investigate grey (GM) and white matter (WM) abnormalities in patients with primary focal dystonia and if such changes are related to clinical features BACKGROUND: Conventional MRI studies suggest that primary focal dystonia is not accompanied by structural brain abnormalities. Voxel-based morphometry and diffusion tensor (DT) MRI reported inconsistent findings on GM and WM damage in these patients. DESIGN/METHODS: 3D T1-weighted and DT MRI scans were obtained from 75 patients with focal dystonia (20 blepharospasm [BL], 15 spasmodic disphonia [SD], 21 spasmodic torticollis [ST], 19 writer’s cramp [WC]) and 83 healthy controls. RESULTS: Patients with BL showed decreased GM in the right postcentral gyrus, rolandic operculum, bilateral cerebellum and left supramarginal and parahippocampal gyri, which was associated with clinical severity. SD patients showed decreased GM in bilateral superior frontal gyrus, and bilateral rolandic operculum/insula and right temporal lobe compared to controls. WC patients did not show regions of GM decrease but GM increases were found in the right middle frontal gyrus and insula, left superior frontal and postcentral gyri, as well as in bilateral thalami. In WC, GM increase of the left supramarginal gyrus was associated with disease duration and WC rating scale movement score. The comparison between ST and controls showed no GM difference. Compared with controls, BL and SD patients showed a widespread pattern of WM damage. Increased mean diffusivity and decreased fractional anisotropy of the right internal and external capsule were found in ST and WC patients. No relationship was observed between WM damage and disease severity and duration in dystonia patients. CONCLUSIONS: Patients with focal dystonia exhibit GM and WM alterations in regions highly relevant to motor function, sensory processing, and cognitive modulation of motor behavior. These abnormalities may contribute to the understanding of the clinical features of focal dystonia. Study Supported by: MPNS #175090 grant