lack of recruitment

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.

Inclusion Criteria:

Case

• Presenting a cervical dystonia that occurs only during handwriting tasks, diagnosed by a neurologist specialised in movement disorders
• Being treated or not by injection of Botulinum Neurotoxin (but last injection > 3 months before the initial assessment)

Control

• No cervical dystonia
• Same sex, age (± 5 years), socio-professional level and hand laterality as the cases

Exclusion Criteria:

Case

• Cervical dystonia occuring in other circumstances than handwriting
• Neurological disease other than cervical dystonia (e.g. Parkinson's syndrome)
• Pain, trauma or pathology of the cervical spine of another cause than cervical dystonia and which have required medical or surgical treatment in the last 6 months preceding the initial assessment

Control

• Cervical disorders requiring medical or surgical treatment in the last 6 months prior to the tests
• Neurological disease affecting the cervical region or the writing hand
• Uncorrected visual disorders