DTI MRI Reveals Abnormalities in Pathways Connecting Brain Regions in Individuals with Writer's Cramp

Abnormalities in the fibers connecting different brain areas may contribute to muscle disorders such as writer's cramp, according to recent research.

Earlier studies of persons with writer's cramp have identified alterations in the gray matter of several brain areas, according to the investigators. These include the basal ganglia (structures that help control and start movement), sensorimotor cortex (controls sensory and motor functions), thalamus (coordinates multiple impulses including some related to the senses), and cerebellum (controls voluntary movements, posture, and balance).

In the new study, Christine Delmaire, M.D., and colleagues from the Centre Hospitalier Régional Universitaire Roger Salengro (Lille, France) and the Institut National de la Santé et de la Récherche Médicale (Paris, France) examined 26 right-handed patients with writer's cramp and 26 right-handed control participants who were the same sex and age but did not have writer's cramp. All participants underwent diffusion-tensor magnetic resonance imaging (DTI MRI), which has been shown to assess the status of white matter (coated nerve fibers that allow impulses to travel through the brain).

The DTI scans of patients with writer's cramp revealed areas of abnormalities in the white matter of nerve pathways connecting the main sensorimotor cortex to brain areas below the cortex, such as the thalamus. The same abnormalities were not observed in healthy controls. "In conclusion, this study suggests that writer's cramp is associated with microstructural changes involving fibers that carry afferents [information from senses to the brain] and efferents [motor information from the brain to the muscles] to the primary sensorimotor cortex," the authors reported in their article, which was published in the April 2009 issue of Archives of Neurology. "However, it is unknown how these changes relate to the physiopathology of the disease."

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Institut National de la Santé et de la Récherche Médicale