Speech-induced lingual dystonia

Abstract

. We report a case of a woman who presented with a speech-in-duced lingual dystonia and discuss the dif-ferential diagnosis and potential therapeu-tic options of this condition. CASEA 49-year-old white woman was re-ferred to our service with a six-year his-tory of tongue protrusion when speak-ing. There was no relevant past or family history of neurological disorders. She did not take neuroleptics or other medications before the onset of symptoms and had no history of facial injury or infection. For six years she visited several physicians and no diagnosis was made. On her first appoint-ment at our service she was taking clon-azepam 2 mg/day without improvement. Her neurological exam showed speech-in-duced tongue protrusion associated with mild dysarthria. The movement disor-der showed no improvement with chew-ing gum (sensory trick). The patient could eat, drink, whistle, sing, and whisper with-out any trouble. A trial with levodopa (750 mg/day) and then trihexyphenidyl (10 mg/day) did not ameliorate symptoms. A number of exams were ordered to rule out secondary dystonia. Drug-in-duced, dopa-responsive, post-traumatic and post-infectious dystonias had already been ruled out, and the absence of family history suggested no heredodegenerative disorder. At this time the diagnoses consid -ered were neuroacanthocytosis, Wilson’s disease, and pantothenate kinase-associat-ed neurodegeneration. Routine hematolog -ical and biochemical evaluation were com-pletely normal including copper levels and number of acanthocytes. Brain magnetic resonance imaging (MRI), electroenceph-alography (EEG), and electromyography (EMG) were within normal parameters. A speech-therapist evaluated the tongue movement during several tasks: repeated words and sentences, reading a short text, automatic speech, singing, vow -el and fricative phoneme prolongation, se-quences of syllables, and spontaneous con -versation. The tongue movement disor-der was identified in all circumstances of speech and in all phonemes, except vowel and sound prolongations. Tongue protru-sion occurred more often in alveodental and alveolar phonemes and less frequent-ly in palatal and velar phonemes. Slower speech and low voice intensity improved tongue protrusion. After the initial work-up ruling out many etiologies, we investigated non-or-ganic causes and referred her to a psychi-atric examination. In this evaluation the patient told that her symptoms started during a period she went through a serious moral dilemma while working in an illegal informal job she considered humiliating. She also told that these symptoms could