Recent findings in cranial and cervical dystonia: how they help us to understand the pathophysiology of dystonia.

Focal dystonia is a hyperkinetic movement disorder confined to a single body district. The most common forms are cranial and cervical dystonia. Cranial dystonia is characterized by muscle contractions causing involuntary forceful eye closure (blepharospasm) or involuntary movements of the lower facial and jaw muscles (oromandibular dystonia), or both manifestations. Cervical dystonia manifests with sustained neck muscle contractions that force the head to twist (torticollis), tilt (laterocollis), flex (anterocollis), or extend (retrocollis) from its normal position. This paper reviews the recent findings in cranial and cervical dystonia and discusses how they contribute to our understanding of the pathophysiology of dystonia.