IAPRD new consensus classification of myoclonus

Anna Latorre; S van der Veen; Ashley Pena; Daniel Truong; Roberto Erro; Steven Frucht; Christos Ganos; Mark Hallett; Belen Perez-Duenas; Malco Rossi; Emmanuel Roze; Marie Vidailhet; Marina Aj de Koning-Tijssen; John N Caviness

doi:10.1016/j.parkreldis.2024.107216

IAPRD new consensus classification of myoclonus

Parkinsonism Relat Disord. 2024 Dec 4:107216. doi: 10.1016/j.parkreldis.2024.107216. Online ahead of print.

Authors

Affiliations

¹ Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, 33 Queen Square, WC1N 3BG, London, United Kingdom.
² Department of Neurology, Movement Disorders Groningen, University Medical Center Groningen HPC AB51, PO Box 30.001, 9700 RB, Groningen, Amsterdam, Netherlands.
³ Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
⁴ Department of Neurosciences, UC Riverside, CA, The Parkinson and Movement Disorder Institute, 9940 Talbert Ave, Fountain Valley, CA, 92708, USA.
⁵ Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Salerno, Italy.
⁶ NYU Langone Department of Neurology, 222 East 41st Street, 14th Floor, New York, NY, 10017, USA.
⁷ Department of Neurology with Experimental Neurology, Charitéplatz 1 Charité Universitätsmedizin Berlin, Berlin, 10117, Berlin, Germany.
⁸ Distinguished NIH Investigator Emeritus, NINDS, NIH, Building 10, Room 7D37, 10 Center Dr MSC 1428, Bethesda, MD, 20892-1428, USA.
⁹ Department of Pediatric Neurology, Hospital Vall d'Hebrón, Barcelona, Spain.
¹⁰ FLENI Foundation, Buenos Aires, Argentina.
¹¹ Département de Neurologie, Groupe Hospitalier Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75651, Paris cedex 13, Paris, France.
¹² Département des Maladies du Système Nerveux Hôpital de la Salpêtrière, Boulevard de l'Hopital, 75013, Paris, France; Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, AP-HP, Hôpital Salpetriere, DMU Neuroscience 6, Paris, France.
¹³ Head of the Expertise Center Movement Disorders Groningen, Department of Neurology, UMCG, University Groningen, Amsterdam, Netherlands.
¹⁴ Department of Neurology, Mayo Clinic, 13400 East Shea Blvd, Scottsdale, AZ, 85259, USA. Electronic address: jcaviness@mayo.edu.

PMID: 39665962
DOI: 10.1016/j.parkreldis.2024.107216

Abstract

Introduction: Recent new advances in myoclonus characterization and etiology justify an update of the 40-year-old respected classification of myoclonus proposed by Marsden, Hallett, and Fahn. New advances include genetic studies and clinical neurophysiology characterization.

Methods: The IAPRD appointed an expert panel to develop a new myoclonus classification. The Delphi Method of consensus determination was employed using a panel of fifteen international experts in myoclonus. In an in-person meeting, an Axis approach, previously used for dystonia and tremor was ratified by the panel: Axis I included clinical and neurophysiology features, Axis II included etiology categories. As a unique part of our Axis approach, Clinical Neurophysiology was included as Axis Ib. The first Delphi survey round queried agreement on major headings in Axes Ia and Ib, myoclonus clinical syndromes, and Axis II. In the second round, the full expert panel was surveyed on constituents and specific characteristics of each feature that had consensus in the first round.

Results: In the first round, the percentage of agreement for the fifty-three out of the 56 items was greater than 60.0 %, indicating strong consensus among expert panel members. In the second round, for Axis Ia, Axis Ib, and Axis II, strong agreement was also achieved. For both rounds, Physiological Myoclonus had the lowest agreement. Comments from the whole panel were incorporated into the consensus results.

Conclusion: This Myoclonus Classification, which reached consensus using the Delphi Method, will facilitate a collaborative effort among myoclonus investigators to find better diagnostics and treatment for myoclonus patients.