The American Academy of Oral Medicine Clinical Practice Statement: Oromandibular dystonia

Surface electromyography for evaluating patients with oromandibular dystonia

OBJECTIVE

To investigate myoelectric signals of dystonic activities in oromandibular dystonia (OMD) subjects using surface electromyography (EMG).

METHODS

Twelve OMD subjects were included in this study. Resting myoelectric activities of the superficial masseter, anterior temporalis, and anterior belly of the digastric muscle on both sides were monitored, and dystonic muscle contractions were recorded using surface EMG. Myoelectric signal amplitude, the type of muscle contraction, and contraction rate for phasic activities were evaluated.

RESULTS

Surface EMG revealed that eight subjects had dystonic muscle activities in the phasic contraction pattern, three subjects had a tonic contraction pattern, and one subject had a mixed pattern. Synchronous contraction of dystonic muscles was frequently observed. Many of the monitored muscles showed high resting amplitudes.

CONCLUSION

Surface EMG detects abnormal muscle activities related to oromandibular dystonia. Surface EMG can serve as an objective method for diagnosing oromandibular dystonia.

Botulinum Toxin Therapy for Oromandibular Dystonia and Other Movement Disorders in the Stomatognathic System

Various movement disorders, such as oromandibular dystonia, oral dyskinesia, bruxism, functional (psychogenic) movement disorder, and tremors, exist in the stomatognathic system. Most patients experiencing involuntary movements due to these disorders visit dentists or oral surgeons, who may be the first healthcare providers. However, differential diagnoses require neurological and dental knowledge. This study aimed to review scientific advances in botulinum toxin therapy for these conditions. The results indicated that botulinum toxin injection is effective and safe, with few side effects in most cases when properly administered by an experienced clinician. The diagnosis and treatment of movement disorders in the stomatognathic system require both neurological and dental or oral surgical knowledge and skills, and well-designed multicenter trials with a multidisciplinary team approach must be necessary to ensure accurate diagnosis and proper treatment.