title: Effects of low frequency filtering on distal compound muscle action potential duration for diagnosis of CIDP: A Japanese-European multicenter prospective study.
abstract: OBJECTIVE
  The duration of the distal compound muscle action potential (DCMAP) is a useful index to detect demyelination in the distal nerve segments. However in published electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP), the cut-off values of DCMAP duration are defined using an EMG low frequency filter of only 20 Hz. We aimed to provide widely-available reference data using several low cut filters.
  
  
  METHODS
  In 13 Japanese and European tertiary centers, DCMAP duration data using 2, 5, 10, and 20 Hz low frequency filters were prospectively collected from 147 normal controls, 59 patients with typical CIDP, and 100 with diabetic polyneuropathy. Optimal cut-off values were calculated with receiver-operating characteristic curves, offering 100% specificity versus normal controls.
  
  
  RESULTS
  The higher low frequency filter was associated with significantly shorter DCMAP duration in all groups. For CIDP diagnosis, the calculated cut-off values had a sensitivity ranging from 51% to 66%, and a specificity versus diabetic neuropathy from 96% to 98%.
  
  
  CONCLUSIONS
  Our results show that DCMAP duration is largely dependent on low frequency filter settings, but is a useful index for CIDP diagnosis when the cut-off values are properly determined at each filter setting.
  
  
  CONCLUSIONS
  Our data provide the systematic reference values of DCMAP duration for CIDP diagnosis available for most EMG laboratories.
authors.affiliation: Department of Neurology, Chiba University Hospital, Chiba, Japan.
authors.forename: Satsuki
authors.initials: S
authors.lastname: Mitsuma
authors.affiliation: Institute of Neuroscience, Neuromuscular Reference Centre, University Hospitals St-Luc, University of Louvain, Brussels, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Van den Bergh
authors.affiliation: Department of Neurophysiology, University Hospitals of Leicester, Leicester, UK.
authors.forename: Yusuf A
authors.initials: YA
authors.lastname: Rajabally
authors.affiliation: Institute of Neuroscience, Neuromuscular Reference Centre, University Hospitals St-Luc, University of Louvain, Brussels, Belgium.
authors.forename: Vinciane
authors.initials: V
authors.lastname: Van Parijs
authors.affiliation: Department of Neurophysiology, University Hospitals of Leicester, Leicester, UK.
authors.forename: Darren
authors.initials: D
authors.lastname: Martin-Lamb
authors.affiliation: Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sonoo
authors.affiliation: Department of Neurology, Kanto Central Hospital, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Inaba
authors.affiliation: Department of Neurology, Tokyo Metropolitan neurological Hospital, Tokyo, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Department of Neurology, Chiba University Hospital, Chiba, Japan.
authors.forename: Sagiri
authors.initials: S
authors.lastname: Isose
authors.affiliation: Clinical Research Center, Chiba University Hospital, Chiba, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Neurology, National Hakone Hospital, Hakone, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Komori
authors.affiliation: Department of Neurology, Chiba University Hospital, Chiba, Japan.
authors.forename: Sonoko
authors.initials: S
authors.lastname: Misawa
authors.affiliation: Department of Neurology, Chiba University Hospital, Chiba, Japan. Electronic address: kuwabara-s@faculty.chiba-u.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuwabara
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004576:Electromyography / Q000379:methods*; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D038622:Internationality; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000175:diagnosis* / Q000503:physiopathology*; D011446:Prospective Studies; D055815:Young Adult
keywords: CIDP; Chronic inflammatory demyelinating polyneuropathy; Demyelination; Distal compound muscle action potential duration; Electrodiagnosis