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July 23, 2007 -- Severe cases of writer’s cramp may have their roots in the brain as well as the hands, according to a new study.
Researchers found people with severe writer’s cramp had less brain tissue in three areas of the brain that connect the senses and control movement in their affected hand.
It’s not clear whether the brain abnormalities caused the writer’s cramp or vice versa, but researchers say the results suggest the brain is involved in the painful ailment.
Although the precise cause of writer’s cramp is unknown, the condition can occur in the hands after years of using the same muscles over and over again during highly skilled tasks like writing, playing the piano, or typing. It’s a form of dystonia, or involuntary, sustained muscle contraction.
Researchers say previous attempts to find structural differences in the brains of people with writer’s cramp using MRI (magnetic resonance imaging) technology have been unsuccessful.
But in this study, published in Neurology, researchers used more advanced brain imaging scans to identify abnormal brain regions in 30 people with severe writer’s cramp in their right hands.
Compared with healthy individuals, the study showed those with severe writer’s cramp had decreased gray matter brain tissue in three areas in the left side of the brain: the cerebellum, the thalamus, and the sensorimotor cortex.
“It’s not clear whether these abnormalities are a cause or a result of the disease,” says researcher Stéphane Lehéricy, MD, PhD, of Salpêtrière Hospital in Paris, in a news release. “The fact that the brain abnormalities are in the areas that control the affected hand suggests that these differences are specific to this problem.”
“Another theory is that the brain structure changed and adapted as a result of the sustained repetitive movement,” says Lehéricy. “Studies have shown that people with no dystonia can experience brain changes due to learning new information, which supports this theory.”