Effect of the Visual Information Change in Functional Dystonia

Cervical dystonia occurring only during the writing task is a rare form for which there is no established treatment. Many authors agree that alteration of sensory integration is associated with dystonia. Similar disturbances in the integration of oculomotor information could have a role in cervical dystonia forms involving visuo-cervico-manual coordination such as handwriting. We hypothesize that orthoptic treatment by wearing prisms when writing (i) will reduce the abnormal posture of the head occurring whilst writing and remove the associated nuchal pain; (ii) the correction after a period of systematic wearing of the prisms during handwriting tasks will have a sustainable effect allowing to keep a normal head position after the suppression of the prisms.