title: Comparison of peak versus onset latency measurements in electrodiagnostic tests for carpal tunnel syndrome.
abstract: OBJECTIVE
  The aim of this prospectively conducted study was to compare the diagnostic accuracy of onset versus peak latency measurements of sensory nerve action potentials in electrodiagnostic studies in diagnosing carpal tunnel syndrome.
  
  
  METHODS
  In 156 consecutive patients with clinically defined carpal tunnel syndrome, standardized nerve conduction studies (DIG1, DIG4, PALM3) were performed. Both onset and peak latency were measured. Sensitivity was calculated using the clinical diagnosis as golden standard. Bland-Altman plots were constructed to assess the agreement for quantitative measurements. Overall agreement, positive and negative percent agreement, and Kappa coefficient were computed.
  
  
  RESULTS
  The Bland-Altman plots, positive and negative percent agreement show good overall agreement. The kappa coefficient was 0.850, 0.847, and 0.815 for DIG1, DIG4, and PALM3, respectively.
  
  
  CONCLUSIONS
  Onset and peak latencies used in electrodiagnostic tests show a good overall agreement in confirming the clinical diagnosis of carpal tunnel syndrome. Because onset latency measurement represents nerve conduction velocity of the fastest conducting fibers, the use of onset latencies is recommend. In case of uncontrollable stimulus artifacts, peak latencies may be used instead.
authors.affiliation: *Department of Neurology and Clinical Neurophysiology, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands; †Department of Neurology and Clinical Neurophysiology, St Lucas Andreas Hospital, Amsterdam, the Netherlands; and ‡Department of Neurology, Vlietland Hospital, Schiedam, the Netherlands.
authors.forename: Kristel M
authors.initials: KM
authors.lastname: Kasius
authors.forename: Franka
authors.initials: F
authors.lastname: Claes
authors.forename: Jan
authors.initials: J
authors.lastname: Meulstee
authors.forename: Henry C
authors.initials: HC
authors.lastname: Weinstein
authors.forename: Wim I M
authors.initials: WI
authors.lastname: Verhagen
mesh_terms: D000328:Adult; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D004558:Electric Stimulation; D004568:Electrodiagnosis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D010525:Peripheral Nerves / Q000503:physiopathology; D011446:Prospective Studies; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values