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Updated: Jan 4, 2026
Author Spotlight: A Battery of Highly Reproducible Behavioral Tests to Validate an Angelman Syndrome Murine Model
Published on: October 20, 2023
Connectivity measures suggest a sub-cortical generator of myoclonus in Angelman syndrome
Edoardo Ferlazzo1, Silvana Franceschetti2, Sara Gasparini1
1Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy; Regional Epilepsy Centre, Great Metropolitan Hospital "Bianchi-Melacrino-Morelli", Reggio Calabria, Italy.
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.
