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A neurophysiological study of myoclonus in patients with DYT11 myoclonus‐dystonia syndrome
Author(s) -
Marelli Cecilia,
Canafoglia Laura,
Zibordi Federica,
Ciano Claudia,
Visani Elisa,
Zorzi Giovanna,
Garavaglia Barbara,
Barzaghi Chiara,
Albanese Alberto,
Soliveri Paola,
Leone Massimo,
Panzica Ferruccio,
Scaioli Vidmer,
Pincherle Alessandro,
Nardocci Nardo,
Franceschetti Silvana
Publication year - 2008
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.22256
Subject(s) - myoclonus , brainstem , neuroscience , dystonia , transcranial magnetic stimulation , somatosensory evoked potential , psychology , silent period , neurophysiology , electromyography , medicine , stimulation
Mutations in the ϵ‐sarcoglycan ( SGCE ) gene have been associated with DYT11 myoclonus‐dystonia syndrome (MDS). The aim of this study was to characterize myoclonus in 9 patients with DYT11‐MDS presenting with predominant myoclonus and mild dystonia by means of neurophysiological techniques. Variously severe multifocal myoclonus occurred in all of the patients, and included short (mean 89.1 ± 13.3 milliseconds) electromyographic bursts without any electroencephalographic correlate, sometimes presenting a pseudo‐rhythmic course. Massive jerks could be evoked by sudden stimuli in 5 patients, showing a “startle‐like” muscle spreading and latencies consistent with a brainstem origin. Somatosensory evoked potentials and long‐loop reflexes were normal, as was silent period and long‐term intracortical inhibition evaluated by means of transcranial magnetic stimulation; however, short‐term intracortical inhibition revealed subtle impairment, and event‐related synchronization (ERS) in the beta band was delayed. Blink reflex recovery was strongly enhanced. Myoclonus in DYT11‐MDS seems to be generated at subcortical level, and possibly involves basal ganglia and brainstem circuitries. Cortical impairment may depend from subcortical dysfunction, but it can also have a role in influencing the myoclonic presentation. The wide distribution of the defective SCGE in DYT11‐MDS may justify the involvement of different brain areas. © 2008 Movement Disorder Society