Writer cramp due to brain abnormalities?

What exactly is writer's cramp? From wikipedia:

Writer's cramp is a form of cramp or spasm that affects certain muscles of the hand and fingers as a result of excessive fine motor activity like writing or playing the piano. It is referred to medically as task-specific focal dystonia of the hand.

From physorg:

People with serious cases of writer’s cramp have brain abnormalities, according to a study published in the July 24, 2007, issue of Neurology, the medical journal of the American Academy of Neurology. People with writer’s cramp had less brain tissue than healthy people in three areas of the brain that connect the senses and movement with their affected hand...

The researchers found that those with writer’s cramp had less grey matter in three areas of the brain: the cerebellum, the thalamus, and the sensorimotor cortex.

At least there are computers, so those with writer's cramp can see if they are any more or less susceptible to carpal tunnel.