title: Event related desynchronisation predicts functional propriospinal myoclonus.
abstract: Recent diagnostic criteria for functional movement disorders have proposed a "laboratory supported" level of diagnostic certainty where the clinical diagnosis is supported by a positive test. For functional myoclonus the Bereitschaftspotential (BP) is generally accepted as a positive laboratory test. We hypothesised that a different EEG measure, event-related desynchronisation (ERD), might be more effective.
  
  
  
  We analysed 20 patients with functional propriospinal myoclonus (fPSM) and 9 controls with organic myoclonus and performed back-averaging for BPs plus time-frequency decomposition to assess ERD and calculated sensitivity and specificity for both techniques.
  
  
  
  The BP was present in only 25% of patients with fPSM while the majority showed a significant ERD (mean 38 Hz; sensitivity 65%). ERD was significant at the group level (p < 0.001), but not the BP (p > 0.05). Both BP and ERD were absent in our control group.
  
  
  
  ERD in high-beta may be a useful new test for positive diagnosis of functional myoclonus.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), Institute of Neurology, London, United Kingdom.|Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Meppelink
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), Institute of Neurology, London, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Little
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), Institute of Neurology, London, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Oswal
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), Institute of Neurology, London, United Kingdom.|Dipartimento di Scienze Neurologiche e del Movimento, Università di Verona, Verona, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Erro
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), Institute of Neurology, London, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Kilner
authors.affiliation: Department of Neurology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: M A J
authors.initials: MAJ
authors.lastname: Tijssen
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Brown
authors.affiliation: Department of Clinical Neurophysiology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Cordovari
authors.affiliation: Department of Cell Sciences, St George's University, London, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Edwards
mesh_terms: D000328:Adult; D000368:Aged; D003265:Contingent Negative Variation / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009207:Myoclonus / Q000503:physiopathology*; D055815:Young Adult
keywords: EEG; Myoclonus