title: Utility of the distal compound muscle action potential duration for diagnosis of demyelinating neuropathies.
abstract: To assess the significance of distal compound muscle action potential (CMAP) duration for diagnosis of demyelinating neuropathies, electrophysiologic data were reviewed from 471 subjects, including 145 normal controls, 60 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 205 with other neuropathy, and 61 with amyotrophic lateral sclerosis (ALS). The duration of distally evoked CMAP was measured in the median, ulnar, tibial, and peroneal nerves. Optimal cut-off values were calculated with receiver-operating characteristic (ROC) curves. In comparison of normal controls and CIDP patients, ROC analyses showed the sufficient area under the curves (82-93%). When the cut-off values in the detection of demyelination were determined as the point with 98% specificity vs. normal on the ROC curves (median, 6.6 ms; ulnar, 6.7 ms; peroneal, 7.6 ms; tibial, 8.8 ms), the sensitivity was 77% for CIDP, with a specificity of 90% vs. ALS and 95% vs. diabetic neuropathy. The distal CMAP duration is a useful index for the detection of distal demyelination. We suggest the above cut-off values for each nerve as one of the electrodiagnostic criteria for demyelinating neuropathies, preferentially affecting the distal nerve terminals, such as CIDP.
authors.affiliation: Department of Neurology, Chiba University Hospital, Chiba, Japan.
authors.forename: Sagiri
authors.initials: S
authors.lastname: Isose
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuwabara
authors.forename: Norito
authors.initials: N
authors.lastname: Kokubun
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mori
authors.forename: Kazumoto
authors.initials: K
authors.lastname: Shibuya
authors.forename: Yukari
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Saiko
authors.initials: S
authors.lastname: Nasu
authors.forename: Yumi
authors.initials: Y
authors.lastname: Fujimaki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Noto
authors.forename: Setsu
authors.initials: S
authors.lastname: Sawai
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Kanai
authors.forename: Koichi
authors.initials: K
authors.lastname: Hirata
authors.forename: Sonoko
authors.initials: S
authors.lastname: Misawa
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002648:Child; D003711:Demyelinating Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D004594:Electrophysiology; D006801:Humans; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult