Facial dystonia, essential blepharospasm and hemifacial spasm.

Movement disorders, or dyskinesias, in the facial region may be categorized in several ways. Dystonic movement disorders in the cranial-cervical region, including essential blepharospasm, Meige syndrome and spasmodic torticollis, are characterized by uncontrollable squeezing movements in the face and neck. These disorders typically present in the fifth and sixth decades of life. Essential blepharospasm is particularly debilitating, as the involuntary eyelid closure that accompanies this condition may result in functional blindness with an otherwise normal visual pathway. Hemifacial spasm is an intermittent, unilateral, spasmodic contraction of the muscles innervated by the facial nerve. This disorder usually presents in the third or fourth decade and has a different underlying pathophysiology than the dystonias. Botulinum A toxin therapy has largely supplanted surgical intervention in the treatment of essential blepharospasm and hemifacial spasm.