Refractory Open Jaw Oromandibular Tardive Dystonia with a Sensory Trick, Treated with Botulinum Toxin: A Case Report.

Jaw-opening oromandibular dystonia (O-OMD) is a clinical subtype of OMD, commonly resistant to treatment. Here, we report a distinct case of tardive O-OMD with a characteristic sensory trick, successfully treated with high-dose botulinum toxin (BTX) injection. A 34-year-old male patient presented with involuntary jaw opening, tongue protrusion, dysarthria, and mild cervical dystonia. The patient reported improved abilities to talk and close his mouth after putting something, like a cigarette, between his teeth. After an unsuccessful treatment with anticholinergic medications, the patient received electromyography-guided BTX injection to the lateral pterygoids (through an extraoral approach), sternocleidomastoids, trapezius, tongue, and platysma muscles. Following the injection, the patient reported marked improvements in his ability to talk and close his mouth without using his sensory trick. One month later, we detected a 58.2% improvement in the Abnormal Involuntary Movement Scale score. Therefore, high-dose BTX injection may be an effective alternative in refractory O-OMD.