title: Sensitivity, specificity, and variability of nerve conduction velocity measurements in carpal tunnel syndrome.
abstract: OBJECTIVE
  To explore the diagnostic values of 8 commonly used electrodiagnostic techniques for measuring median nerve conduction velocity (NCV) in carpal tunnel syndrome (CTS).
  
  
  METHODS
  Sensitivity and specificity analyses.
  
  
  METHODS
  A hospital-based electrodiagnostic laboratory.
  
  
  METHODS
  Forty-four normal hands and 136 symptomatic hands.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  (1) Long-segment studies: antidromic wrist-to-digit sensory NCV without subtraction, (2) short-segment studies: transcarpal palm-to-wrist mixed NCV without subtraction, and (3) 2 segment studies: antidromic transcarpal sensory NCV with subtraction (differential calculation from wrist-to-digit and palm-to-digit segments). Both onset and peak latency values were obtained for calculating the NCV. Sensitivity, specificity, and coefficient of variance were calculated for each NCV study.
  
  
  RESULTS
  The short-segment, onset latency-based transcarpal mixed NCV yielded the highest sensitivity (75%).
  
  
  CONCLUSIONS
  Results from measurement of a single, short-nerve segment tended to be superior to results obtained by either long-segment studies or differential subtraction between 2 segments of the same nerve in the electrodiagnosis of CTS. Explanations for our results are offered from both electrophysiologic and statistical perspectives.
authors.affiliation: Physical Medicine and Rehabilitation Service, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA. henrylew@stanford.edu
authors.forename: Henry L
authors.initials: HL
authors.lastname: Lew
authors.forename: Elaine S
authors.initials: ES
authors.lastname: Date
authors.forename: Steven S
authors.initials: SS
authors.lastname: Pan
authors.forename: Peter
authors.initials: P
authors.lastname: Wu
authors.forename: Paul F
authors.initials: PF
authors.lastname: Ware
authors.forename: Wade S
authors.initials: WS
authors.lastname: Kingery
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis*; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D015588:Observer Variation; D011930:Reaction Time / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity