Analysis of pen grip force in writer's cramp

One cardinal symptom of writer's cramp is uncontrollable muscle co-contractions and hyperactivity in agonist and antagonist muscles during handwriting. There is however only limited amount of information about the actual forces produced during handwriting. Over the past decade researches using digitizing tablets have largely focussed on kinematic measurements to analyse the graphomotor skills in patients with writer's cramp. Specially equipped pens enabled the measurement of normal/axial pen forces. However clinical practice suggests that the measurement of the grip forces exerted against the pen surface may be…