You searched for: “graphospasm
1. Writer’s cramp.
2. Muscular spasms of thumb and forefinger while writing with a pen or pencil.

A dystonia that affects the muscles of the hand and sometimes the forearm and only occurs during handwriting.

Similar focal dystonias have also been called typist's cramp, pianist's cramp, musician's cramp, golfer's cramp, and computer cramp.