Writer’s cramp, or graphospasm, is a focal dystonia of the hand in which dystonic posturing is induced specifically by writing: this is the most common task-specific dystonia. The involuntary movements may eventually make it impossible to write with the dominant hand. Learning to write with the opposite hand may only be a partial solution, since it too may become affected. Muscle fatigue may make writing more legible. Writer’s cramp is much commoner than primary writing tremor as a cause of writing difficulty.
Botulinum toxin injections may be of benefit if relatively few muscles are affected. There may be an associated carpal tunnel syndrome.
Sheehy MP, Marsden CD. Writer’s cramp – a focal dystonia. Brain
1982; 105: 461-480