Muscle disorders like writer's cramp may result from abnormalities in fibres connecting different brain areas, according to a study.
Dr. Christine Delmaire, of Centre Hospitalier Regional Universitaire Roger Salengro, Lille, France, and Institut ational de la Sante et de la Recherche Medicale, Paris, came to this conclusion after studying 26 right-handed patients with writer's cramp and 26 right-handed control participants, who were the same sex and age.
All subjects underwent diffusion-tensor magnetic resonance imaging (DTI) that assesses the status of white matter, coated nerve fibres that allow impulses to travel through the brain.
Christine said that the DTI scans of the writer's cramp patients 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 researchers further revealed that the same abnormalities were not observed in healthy controls.
"In conclusion, his study suggests hat writer's ramp 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. However, it is unknown how these changes relate to the physiopathology of the disease," the authors write.
The study has been published in the Archives of Neurology, one of the JAMA/Archives journals.