Description

A 49-year-old woman with no medical history started to show difficulty in speaking 1 year earlier. She was not taking any antipsychotics. Except for difficulty in speaking, her neurological examination results were normal. Her brain MRI was unremarkable and no causative abnormality was found in her blood test, including copper and ceruloplasmin levels and thyroid parameters. A neuropsychiatric consultation revealed no depression or psychiatric problem. The patient eventually noticed the dramatic amelioration of her symptoms when chewing gum or pressing her neck (video 1). These could have been acting as sensory tricks for her isolated speech-induced lingual dystonia.1 There was no history of orofacial injury or recent viral infection that could have caused secondary lingual dystonia. Trihexyphenidyl (up to 8 mg/day) or diazepam (up to 4 mg/day) had no benefit and induced severe dry mouth or sleepiness. We also tried baclofen starting at 5 mg/day, however, the patient reported sleepiness at that dose; it was stopped. We applied these drugs separately. To rule out dopa-responsive dystonia (DYT5) and Parkinson's disease, we attempted levodopa/carbidopa treatment (up to 300 mg), but with no benefit.

In this rare type of focal dystonia, medical refractory symptoms can be improved by sensory tricks, and sensory tricks for idiopathic focal dystonia are helpful in differentiating this condition from psychogenic movement disorder.2