Diffusion Abnormalities in the Primary Sensorimotor Pathways in Writer's Cramp

Abstract

To determine whether there are diffusion abnormalities along the fibers connecting sensorimotor regions, including the primary sensorimotor areas and the striatum, in patients with writer's cramp using voxelbased diffusion analysis and fiber tracking. Recent studies have shown structural changes in these regions in writer's cramp. Design: Patient and control group comparison. Setting: Referral center for movement disorders. Participants: Twenty-six right-handed patients with writer's cramp and 26 right-handed healthy control subjects matched for sex and age. Interventions: Clinical motor evaluations. Main Outcome Measures: Fractional anisotropy changes and results of fiber tracking in writer's cramp. Results: Diffusion-tensor imaging revealed increased fractional anisotropy bilaterally in the white matter of the posterior limb of the internal capsule and adjacent structures in the patients with writer's cramp. Fiber tracking demonstrated that fractional anisotropy changes involve fiber tracts connecting the primary sensorimotor areas with subcortical structures. Conclusions: Diffusion abnormalities are present in fiber tracts connecting the primary sensorimotor areas with subcortical structures in writer's cramp. These abnormalities strengthen the role of the corticosubcortical pathways in the pathophysiologic mechanisms of writer's cramp.

A Transverse and Longitudinal MR Imaging Voxel-Based Morphometry Study in Patients with Primary Cervical Dystonia

“…[19][20][21][22] In patients with focal hand dystonia, VBM data receive support from the recent finding of DTI abnormalities in the fiber tracts connecting the primary sensorimotor areas with subcortical structures. 23 The reduced connectivity reported in the subcortical white matter of the sensorimotor area in DYT1 mutation carriers 24 further supports the axonal loss in this subcortical white matter region and abnormalities in the neuronal density in the overlying cortex, which may contribute to the development of dystonia.…”

Structural, functional and molecular imaging of the brain in primary focal dystonia—A review

“…One study comparing 26 WC patients with controls, found an increase in FA in the fiber tracks connecting the primary sensorimotor areas to subcortical structures, including the corticospinal tract (Delmaire et al, 2009).…”

A preliminary study of the neuroanatomical correlates of primary writing tremor: role of cerebellum

“…In the present study, patients with PWT compared to controls had significantly reduced FA in the ATR, cingulum, IFO, ILF, forceps minor, and the uncinate fasciculus. While DTI has been used to explain the pathophysiology of ET [28][29][30] and WC [31], to the best of our knowledge, there are no DTI studies in PWT. In a DTI study in WC, FA values were reported to be increased bilaterally in the white matter of the posterior limb of the internal capsule and adjacent structures in the patients compared to the controls.…”