{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T09:57:45Z","timestamp":1787738265853,"version":"build-2784847793"},"reference-count":40,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2024,2,22]],"date-time":"2024-02-22T00:00:00Z","timestamp":1708560000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["movementdisorders.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Movement Disorders"],"published-print":{"date-parts":[[2024,4]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Introduction<\/jats:title><jats:p>Negative myoclonus (NM) is an involuntary movement caused by a sudden interruption of muscular activity, resulting in gait problems and falls.<\/jats:p><\/jats:sec><jats:sec><jats:title>Objective<\/jats:title><jats:p>To establish frequency, clinical impact, and neurophysiology of NM in progressive myoclonus ataxia (PMA) patients.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Clinical, neurophysiological, and genetic data of 14 PMA individuals from University Medical Centre Groningen (UMCG) Expertise Center Movement Disorder Groningen were retrospectively collected. Neurophysiological examination included video\u2010electromyography\u2010accelerometry assessment in all patients and electroencephalography (EEG) examination in 13 individuals. Jerk\u2010locked (or silent period\u2010locked) back\u2010averaging and cortico\u2010muscular coherence (CMC) analysis aided the classification of myoclonus.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>NM was present in 6 (NM+) and absent in 8 (NM\u2212) PMA patients. NM+ individuals have more frequent falls (100% vs. 37.5%) and higher scores on the Gross Motor Function Classification System (GMFCS) (4.3 \u00b10.74 vs. 2.5 \u00b11.2) than NM\u2212 individuals. Genetic background of NM+ included <jats:italic>GOSR2<\/jats:italic> and <jats:italic>SEMA6B<\/jats:italic>, while that of NM\u2212 included <jats:italic>ATM<\/jats:italic>, <jats:italic>KCNC3<\/jats:italic>, <jats:italic>NUS1<\/jats:italic>, <jats:italic>STPBN2<\/jats:italic>, and <jats:italic>GOSR2<\/jats:italic>. NM was frequently preceded by positive myoclonus (PM) and silent\u2010period length was between 88 and 194\u2009ms. EEG epileptiform discharges were associated with NM in 2 cases. PM was classified as cortical in 5 NM+ and 2 NM\u2212 through EEG inspection, jerk\u2010locked back\u2010averaging, or CMC analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Discussion<\/jats:title><jats:p>Neurophysiological examination is crucial for detecting NM that could be missed on clinical examination due to a preceding PM. Evidence points to a cortical origin of NM, an association with more severe motor phenotype, and suggests the presence of genetic disorders causing either a PMA or progressive myoclonus epilepsy, rather than pure PMA phenotype. \u00a9 2024 The Authors. <jats:italic>Movement Disorders<\/jats:italic> published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.<\/jats:p><\/jats:sec>","DOI":"10.1002\/mds.29741","type":"journal-article","created":{"date-parts":[[2024,2,22]],"date-time":"2024-02-22T09:01:25Z","timestamp":1708592485000},"page":"674-683","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Negative Myoclonus: Neurophysiological Study and Clinical Impact in Progressive Myoclonus Ataxia"],"prefix":"10.1002","volume":"39","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9634-6572","authenticated-orcid":false,"given":"Luca","family":"Pollini","sequence":"first","affiliation":[{"name":"Department of Human Neuroscience Sapienza University of Rome  Rome Italy"},{"name":"Department of Neurology University of Groningen, University Medical Centre Groningen (UMCG)  Groningen The Netherlands"},{"name":"Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG)  Groningen The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sterre","family":"van der Veen","sequence":"additional","affiliation":[{"name":"Department of Neurology University of Groningen, University Medical Centre Groningen (UMCG)  Groningen The Netherlands"},{"name":"Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG)  Groningen The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan 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