title: Comparison of 2-limb versus 3-limb electrodiagnostic studies in the evaluation of chronic inflammatory demyelinating polyneuropathy.
abstract: BACKGROUND
  European Federation of Neurological Societies/Peripheral Nerve Society electrodiagnostic (EDx) criteria for the definite diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) require the presence of demyelinating findings (DF) in at least 2 nerves. Data are lacking, however, regarding the optimal number of nerves to test.
  
  
  METHODS
  We retrospectively reviewed EDx data from 53 patients with CIDP and compared the number of DF found on 2- and 3-limb testing.
  
  
  RESULTS
  A median of 3 (range 2-5) DF were found on 2-limb testing compared with 5 (range 4-7) DF when 3 limbs were evaluated. Two-limb EDx studies were sufficient to diagnose definite CIDP in 92.3% of typical, 84.2% of asymmetric, and 66.7% of distal phenotypes. Testing a third limb increased diagnostic certainty in 11 patients (20.8%) to definite CIDP.
  
  
  CONCLUSIONS
  Three-limb testing may increase diagnostic sensitivity of definite CIDP, especially in patients with atypical phenotypes. Larger prospective studies are needed to better assess the benefit of performing 3-limb EDx studies.
authors.affiliation: Peripheral Neuropathy Center, Weill Cornell Medical Center, 1305 York Avenue, Second Floor, New York, New York, 10021, USA.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Vo
authors.forename: Aneliya
authors.initials: A
authors.lastname: Hanineva
authors.forename: Russell L
authors.initials: RL
authors.lastname: Chin
authors.forename: Bridget T
authors.initials: BT
authors.lastname: Carey
authors.forename: Norman
authors.initials: N
authors.lastname: Latov
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Langsdorf
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000503:physiopathology; D004568:Electrodiagnosis / Q000379:methods; D005121:Extremities / Q000294:innervation / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D010525:Peripheral Nerves / Q000503:physiopathology; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: chronic inflammatory demyelinating polyneuropathy; demyelinating findings; electrodiagnosis; phenotype; sensitivity