Oromandibular dystonia (cranial dystonia)

Oromandibular dystonia is a focal dystonia characterized by forceful contractions of the face, jaw, and/or tongue causing difficulty in opening and closing the mouth and often affecting chewing and speech. Another word used to describe dystonia of this kind is cranial dystonia.Cranial dystonia is a broad description for dystonia that affects any part of the head. Dystonia that affects the facial muscles and lips of musicians who play wind instruments is called embouchure dystonia. Dystonia that specifically affects the tongue is called lingual dystonia. Oromandibular dystonia may be primary or secondary.

Terms used to describe oromandibular dystonia include: orofaciomandibular dystonia; orofacial-buccal dystonia; jaw dystonia, tongue dystonia (lingual dystonia); embouchure dystonia; cranial dystonia; adult onset focal dystonia. When oromandibular dystonia occurs with blepharospasm, it may be referred to as Meige’s syndrome.

Symptoms
 

Oromandibular dystonia is often associated with dystonia of the neck muscles (cervical dystonia/spasmodis torticollis), eyelids (blepharospasm), or larynx (spasmodic dysphonia). The combination of upper and lower dystonia is sometimes called cranial-cervical dystonia. Sometimes symptoms of oromandibular are task-specific and occur only during activities such as speaking or chewing. Paradoxically, in some people, activities like speaking and chewing reduce symptoms. Difficulty in swallowing is a common aspect of oromandibular dystonia if the jaw is affected, and spasms in the tongue can also make it difficult to swallow.

Drug-induced dystonia often manifests as symptoms in the facial muscles. Secondary oromandibular dystonia may persist during sleep.

Oromandibular dystonia symptoms usually begin later in life, between the ages of 40 and 70 years, and appear to be more common in women than in men.

Cause
 

Oromandibular dystonia may be primary (meaning that it is the only apparent neurological disorder, with or without a family history) or be brought about by secondary causes such as drug exposure or disorders such as Wilson’s disease. Cases of inherited cranial dystonia have been reported, often in conjunction with DYT1 generalized dystonia.

Diagnosis
 

Diagnosis of oromandibular dystonia is based on information from the individual and the physical and neurological examination. At this time, there is no test to confirm diagnosis of oromandibular dystonia, and in most cases assorted laboratory tests are normal.

Oromandibular dystonia should not be mistaken for temporomandibular joint disease (TMJ), which is an arthritic condition.

Treatment
 

Treatment for oromandibular dystonia must be highly customized to the individual. A multitude of oral medications has been studied to determine benefit for people with oromandibular dystonia. About one-third of people's symptoms improve when treated with oral medications such as Klonapin® (clonazepam), Artane® (trihexyphenidyl), diazepam (Valium®), tetrabenezine, and Lioresal® (baclofen).

Although the symptoms may vary from person to person, approximately 70% of people with oromandibular dystonia experience some reduction of spasm and improvement of chewing and speech after injection of botulinum toxin into the masseter, temporalis, and lateral pterygoid muscles. Botulinum toxin injections are most effective in jaw-closure dystonia, while treating jaw-opening dystonia may be more challenging. Botulinum toxin injections may also be an option for lingual dystonia. Side effects such as swallowing difficulties, slurred speech, and excess weakness in injected muscles may occur, but these side effects are usually transient and well tolerated.

Oromandibular dystonia may respond surprisingly well to the use of sensory tricks to temporarily reduce symptoms. For example, gently touching the lips or chin, chewing gum, talking, biting on a toothpick, or placing a finger near an eye or underneath the chin may cause symptoms to subside temporarily. Different sensory tricks work for different people, and if a person finds a sensory trick that works, it usually continues to work.

Speech and swallowing therapy may lessen spasms, improve range of motion, strengthen unaffected muscles, and facilitate speech and swallowing. Regular relaxation practices may benefit overall well being.