Connectivity measures suggest a sub-cortical generator of myoclonus in Angelman syndrome

Edoardo Ferlazzo, Silvana Franceschetti, Sara Gasparini, Maurizio Elia, Laura Canafoglia, Chiara Pantaleoni, Michele Ascoli, Tiziana D'Agostino, Chiara Sueri, Giulia Ferrigno, Ferruccio Panzica, Vittoria Cianci, Umberto Aguglia

Research output: Contribution to journalArticlepeer-review


Objective: The clinical and neurophysiological characteristics of myoclonus in Angelman syndrome (AS) have been evaluated in single case or small cohorts, with contrasting results. We evaluated the features of myoclonus in a wide cohort of AS patients. Methods: We performed polygraphic EEG-EMG recording in 24 patients with genetically confirmed AS and myoclonus. Neurophysiological investigations included jerk-locked back-averaging (JLBA), cortico-muscular coherence (CMC) and generalised partial directed coherence (GPDC). CMC and GPDC analyses were compared to those obtained from 10 healthy controls (HC). Results: Twenty-four patients (aged 3–35 years, median 20) were evaluated. Sequences of quasi-continuous rhythmic jerks mostly occurred at alpha frequency or just below (mean 8.4 ± 1.4 Hz), without EEG correlate. JLBA did not show any clear transient preceding the jerks. CMC showed bilateral over-threshold CMC in alpha band that was prominent on the contralateral hemisphere in the patient group as compared to HC group. GPDC showed a significantly higher alpha outflow from both hemispheres toward activated muscles in the patient group, and a significantly higher beta outflow from contralateral hemisphere in the HC group. Conclusions: These neurophysiological findings suggest a subcortical generator of myoclonus in AS. Significance: Myoclonus in AS has not a cortical origin as previously hypothesised.

Original languageEnglish
Pages (from-to)2231-2237
Number of pages7
JournalClinical Neurophysiology
Issue number12
Publication statusPublished - Dec 2019


  • Coherence
  • EEG
  • Jerk-locked back averaging
  • Jerks
  • Polygraphy

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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