Botulinum Toxin Treatment and Oromandibular Dystonia

Oromandibular dystonia is a segmental cranial dystonia that affects the perioral mimic muscles, orbicularis oculi, vocal cords and cervical muscles. It is the second most common cranial dystonia after blepharospasm and can occur in isolation or together with other forms of craniocervical dystonia. Oromandibular dystonia is a disabling problem that impairs chewing, swallowing and speech. It is idiopathic in the majority of cases, but can be found in association with other diseases, such as tardive dyskinesia. Botulinum toxin injection in the management of oromandibular dystonia is the best-known treatment, albeit less effective than in other focal hyperkinesias. Knowledge of the anatomy of the tongue and chewing muscles is essential, since these muscles are hard to reach and have more than one function. Electromyographic guidance is needed during the injections in all patients, because some of these muscles are not superficially localized and are nonpalpable. Dosage and treatment approaches vary among patients and must be individualized. Side effects given in decreasing order of frequency are: dysphagia, dysarthria, swelling of the face and difficulty in chewing. (Archives of Neuropsychiatry 2010; 47 Supplement: 15-8)