[Craniocervical dystonia. Pragmatic general concept or nosologic entity?]

The focal dystonias of cranial-nerve innervated muscles are described. They include the ocular dystonia, blepharospasmus and other facial dystonias, mandibular dystonia, pharyngeal dystonia, spasmodic dysphonia, external laryngeal dystonia, spasmodic torticollis and lingual dystonia. They share similar clinical aspects such as the inadequate co-contraction of antagonistic muscles, dystonic overflow of muscle activity to muscles not normally involved, similar facilitating and inhibitory activities and various "antagonistic gestures". Genetic, imaging, neuroanatomic, physiologic and pharmacologic findings suggest common pathogenetic mechanisms for these diseases. Similar therapeutic approaches are established. The frequent and variable combinations of these focal dystonias and their similar pathogenetic background favour their common classification as craniocervial dystonias.