Speech‐activated myoclonus: An uncommon form of action myoclonus

Abstract

We describe an unusual form of facial myoclonus activated by speech in 3 patients with different underlying neurological diseases and present the electrophysiological investigations and results of structural and functional imaging. In 1 of 2 patients in whom jerk-locked electroencephalogram (EEG) back-averaging was done, a cortical potential clearly preceded the facial jerks. In the second patient, a cortical potential preceding the jerk was not certain. In the third patient, the resting EEG contained outbursts of symmetric, slower frequencies of indeterminate significance. An epileptiform disorder was suspected in this patient.

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

“…Speechactivated myoclonus is typically a function of the type of speech: spontaneous or rote. 5 In their case series, Slee et al 5 demonstrated that oropharyngeal movements not involving the vocal cords (e.g. whistling, chewing, swallowing) failed to trigger myoclonus.…”

“…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.…”

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

“…Speech-activated myoclonus is typically a function of the type of speech: spontaneous or rote. 5 In their case series, Slee et al 5 demonstrated that oropharyngeal movements not involving the vocal cords (e.g. whistling, chewing, swallowing) failed to trigger myoclonus.…”

“…The authors also noted that “internal speech” and writing did not activate myoclonus, concluding that in all three patients, the myoclonus was elicited by vocal speech production. 5 …”

“…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.…”