Myoclonus affecting speech reduced by concurrent handwriting

Abstract

We report a case of action myoclonus affecting speech in which concurrent performance of handwriting reduced the impact on intelligibility. This attenuation from writing was greater than from a nonlinguistic manual task, suggesting a role for linguistic processing in the effect.There have been previous reports of facial and oral myoclonus selectively activated by speech and not by other purposeful movements of the face and mouth such as whistling, blowing, and swallowing, 1 and myoclonus selectively activated by mastication but not speech, kissing, and whistling. 2 In one case, facial and oral myoclonus was activated by speech and writing but not nonlinguistic tasks such as prolonged phonation, finger tapping, copying a figure in drawing, or language comprehension. 3 This latter case is consistent with processes of expressive language underlying activation of the myoclonic jerks. Our case is the first reported, as far as we are aware, in which additional linguistic processing attenuates rather than activates myoclonus affecting speech, with an impact on function via improved intelligibility.A 35-year-old right handed man was admitted to hospital with acute epiglotitis and suffered respiratory arrest during an attempt to secure his airway. This caused hypoxic brain injury. He required ventilation via a tracheostomy for approximately 3 weeks. During this stage he developed generalized myoclonic jerks. Three months following his injury, he was admitted to a neurological rehabilitation unit with a diagnosis of Lance-Adams syndrome. At this point he had full power and normal reflexes in all limbs, his muscle tone was normal, however myoclonic movements in all limbs, trunk, head, neck, and face occurred when initiating purposeful movements. The extent of myoclonus increased with increased activity. The patient also experienced cognitive deficits in terms of executive function, i.e. planning, problem solving, and reasoning. His language skills were preserved. Previous medical history included tonsillectomy and adenoidectomy performed 1 year prior to this admission.The patient's oral, laryngeal, and respiratory muscles were affected by his myoclonus, activated upon attempting to speak. This dysarthria was characterized by episodes of extended voicing, unstable with respect to volume, pitch, and placement of all articulators (lips, tongue, and velum). He made multiple attempts to produce affected segments of speech, reducing his fluency in producing utterances. Other segments not affected bythe dysarthria were fully intelligible, produced slowly and without reference to utterance-level intonation frames. There was no effect of word position or grammatical category on the dysarthria. The patient also had swallowing difficulties activated upon eating and drinking. Videofluoroscopy of a barium swallow revealed uncoordinated tongue movement within the oral cavity and pharynx, and reduced pharyngeal peristalsis. These resulted in difficulties in all stages of bolus preparation and movement, despite which he managed a diet of s...

Speech-activated Myoclonus Mimicking Stuttering in a Patient with Myoclonus–Dystonia Syndrome

“…The neural substrate of acquired neurogenic stuttering remains elusive, in large part because of the myriad brain structures and varied etiologies implicated. 1 , 4 Speech-activated myoclonus is a rare entity that can mimic stuttering and, like stuttering and other forms of myoclonus, is caused by a wide array of etiologies, most of which are acquired: neurodegenerative disease, 5 clozapine, 5 , 6 pharyngitis, 5 reading epilepsy, 7 reflex seizures in the context of juvenile myoclonic epilepsy, 7 , 8 localization-related epilepsy secondary to hypoxic brain injury, 9 Lance–Adams syndrome, 10 and as an unclear consequence of primary intestinal T-cell non-Hodgkin’s lymphoma. 11 Here we report a patient with genetic dystonia, myoclonus–dystonia syndrome (MDS), with an identified disease-causing mutation who presented with speech-activated myoclonus mimicking stuttering.…”