Benign Idiopathic Myoclonus: A New Clinical Entity?
Giorgia Sciacca1,2, A M Madelein van der Stouwe1, Sterre van der Veen1
1Expertise Center Movement Disorders Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands.
Movement Disorders Clinical Practice
|March 15, 2025
Summary
We propose "benign idiopathic myoclonus," a new type of physiologic myoclonus. This condition features adolescent-onset distal limb jerks that are typically benign and do not require treatment.
Area of Science:
- Neurology
- Movement Disorders
Background:
- Myoclonus is an involuntary, brief, shock-like movement.
- Classified by etiology: physiologic, essential, epileptic, and symptomatic.
- Physiologic myoclonus is typically benign and non-progressive.
Purpose of the Study:
- To propose a new nosological entity: "benign idiopathic myoclonus."
- To characterize a cohort of patients with isolated adolescent-onset distal limb myoclonus.
Main Methods:
- Clinical and neurophysiological examinations were performed.
- Included electromyography (EMG), somatosensory evoked potentials (SEPs), electroencephalography (EEG)-EMG with back-averaging (BA), and cortico-muscular coherence (CMC).
Main Results:
- Fifteen patients with adolescent-onset distal myoclonus were assessed.
- Neurophysiological tests confirmed myoclonus, with a cortical origin in 40%.
- Follow-up showed stability or remission in most patients, with one experiencing slight progression.
Conclusions:
- "Benign idiopathic myoclonus" is a suggested phenotype of physiologic myoclonus.
- Characterized by adolescent-onset distal myoclonus with a benign course.
- May represent a distinct subgroup of physiologic myoclonus requiring further multicenter study.
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