Advanced Neuroimaging Techniques to Assess Brain Structural Abnormalities in Writer’s Cramp Primary Dystonia (P4.319)

OBJECTIVE: To investigate cortical and subcortical gray matter (GM) and white matter (WM) patterns of alterations characterizing Writer’s Cramp (WC) primary dystonia. BACKGROUND: Several recent neuroimaging studies showed cortical thickening as well as WM damage in sensorimotor as well as extra-sensorimotor regions in WC, suggesting a complex network dysfunction playing a role in the development of dystonia. DESIGN/METHODS: T1-weighted and diffusion tensor (DT) MRI scans were obtained from 19 WC patients and 30 healthy controls (HC). Surface-based morphometry analysis was used to assess cortical measures. FMRIB-FIRST tool in FSL was used to segment basal ganglia on 3D T1-weighted images; then, volumes and DT MRI metrics were measured for each GM nucleus. TBSS was used to perform a voxel-wise analysis of DT MRI metrics. The effects of disease severity were examined by correlating GM and WM metrics with disease duration and WC severity scales. RESULTS: Increases in cortical area and volume were found bilaterally in paracentral and postcentral gyri as well as supramarginal and temporo-occipital gyri in WC patients compared with HC. No cortical thickness abnormalities were found. Relative to controls, WC patients did not show significant differences in the basal ganglia volumes, while they showed altered DT MRI metrics of the right caudate, pallidum and putamen. WM microstructural analysis in WC showed increased diffusivities of the corpus callosum and thalamic radiations bilaterally, and right corticospinal tracts and major associative tracts. WCRS score correlated with WM damage of the corpus callosum. CONCLUSIONS: These findings corroborate the hypothesis that WC dystonia is a complex disturbance which results from the involvement of both sensorimotor and associative neural circuits. Advanced MRI techniques may give insight in the pathophysiology of this multifaceted disease.