Clinical Utility of Neurophysiologic Classification (and Declassification) of Myoclonus

Mov Disord. 2024 Dec;39(12):2242-2248. doi: 10.1002/mds.30022. Epub 2024 Oct 14.

Abstract

Background: Movement clinical neurophysiology studies can distinguish myoclonus, tremor, and other jerky movements; however, there has been limited demonstration of their real-world clinical impact.

Objective: The aim was to investigate movement study utility in clarifying movement classification and guiding patient management.

Method: A retrospective study of myoclonus-related movement studies was performed.

Results: Of 262 patients referred for consideration of myoclonus, 105 (40%) had myoclonus, 156 (59%) had no myoclonus (the commonest alternative classifications were functional jerks and tremor), and 1 was uncertain. An additional 29 studies identified myoclonus without prior clinical suspicion. A total of 119 of 134 (89%) myoclonus patients had a specific neurophysiologic subtype identified, most commonly cortical (64, 54%). Diagnostic differential narrowed in 60% of patients, and a new diagnosis was made in 42 (14%) patients. Medication changes were made in 151 patients (52%), with improvement in 35 of 51 (67%) with follow-up.

Conclusions: Movement studies effectively determined movement classification and identified unsuspected myoclonus, leading to changes in diagnosis and management. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords: classification; diagnosis; movement disorders; myoclonus; neurophysiology.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Electroencephalography / methods
  • Electromyography / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Myoclonus* / classification
  • Myoclonus* / diagnosis
  • Myoclonus* / physiopathology
  • Retrospective Studies
  • Tremor / classification
  • Tremor / diagnosis
  • Tremor / physiopathology
  • Young Adult