title: Duration of the distal compound muscle action potential for diagnosis of chronic inflammatory demyelinating polyneuropathy: effects of low-cut filters.
abstract: OBJECTIVE
  In current electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy, the cutoff values of distal compound muscle action potential (DCMAP) duration are defined using electromyogram low-cut filter setting of 20 Hz. We aimed to assess effects of low-cut filter on DCMAP duration (10 vs. 20 Hz).
  
  
  METHODS
  We prospectively measured DCMAP duration in 130 normal controls and 42 patients, fulfilling diagnostic criteria for typical chronic inflammatory demyelinating polyneuropathy by European Federation of Neurological Societies/Peripheral Nerve Society.
  
  
  RESULTS
  Distal compound muscle action potential duration was significantly shortened with 20-Hz than 10-Hz filtering. When the cutoff values were defined as the upper limit of normal (ULN, mean + 2.5SD), the sensitivity/specificity was 67%/95% in 10-Hz recordings, and 69%/95% in 20-Hz recordings. This diagnostic accuracy was similar to that defined by receiver operating characteristic analyses.
  
  
  CONCLUSIONS
  Distal compound muscle action potential duration significantly affected by the low-cut electromyogram filter setting, but with at least 10 and 20 Hz, the diagnostic accuracy is similar.
authors.affiliation: *Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan; †Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan; ‡Department of Neurology, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan; §Department of Neurology, Kyorin University School of Medicine, Tokyo, Japan; ‖Department of Neurology, National Hakone Hospital, Kanagawa, Japan; ¶Department of Neurology, Dokkyo Medical University, Tochigi, Japan; #Department of Neurology, Kanto Central Hospital, Tokyo, Japan; and **Department of Neurology, Nissan Tamagawa Hospital, Tokyo, Japan.
authors.forename: Sagiri
authors.initials: S
authors.lastname: Isose
authors.forename: Sonoko
authors.initials: S
authors.lastname: Misawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sonoo
authors.forename: Toshio
authors.initials: T
authors.lastname: Shimuzu
authors.forename: Chizuko
authors.initials: C
authors.lastname: Oishi
authors.forename: Kazumoto
authors.initials: K
authors.lastname: Shibuya
authors.forename: Saiko
authors.initials: S
authors.lastname: Nasu
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Satsuki
authors.initials: S
authors.lastname: Mitsuma
authors.forename: Minako
authors.initials: M
authors.lastname: Beppu
authors.forename: Shigeki
authors.initials: S
authors.lastname: Omori
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Komori
authors.forename: Norito
authors.initials: N
authors.lastname: Kokubun
authors.forename: Akira
authors.initials: A
authors.lastname: Inaba
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hirashima
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; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000503:physiopathology; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology*; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000175:diagnosis* / Q000503:physiopathology*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult