Proficiency of nerve conduction using standard methods and reference values (cl. NPhys Trial 4)


  • Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors have full access to all the data and the right to publish any and all data, separate and apart from the guidance of any sponsor.

  • Disclosure: P.J.D. serves as an Associate Editor for Diabetes and receives an honorarium. His laboratory receives financial support from the Mayo Foundation; Pfizer, Inc.; Isis, Inc.; and Alnylam, Inc.; and previously from the National Institutes of Health (NS 36797), FDA, and other pharmaceutical companies.

  • This study was supported in part by Mayo Foundation Funds and grants obtained from the National Institute of Neurological Disorders and Stroke (R01-NS36797 to P.J.D.) and the National Institute on Aging (R01-AG34676 to W.A.R.).



The Cl. NPhys Trial 3 showed that attributes of nerve conduction (NC) were without significant intraobserver differences, although there were significant interobserver differences. Methods: Trial 4 tested whether use of written instructions and pretrial agreement on techniques and use of standard reference values, diagnostic percentile values, or broader categorization of abnormality could reduce significant interobserver disagreement and improve agreement among clinical neurophysiologists. Results: The Trial 4 modifications markedly decreased, but did not eliminate, significant interobserver differences of measured attributes of NC. Use of standard reference values and defined percentile values of abnormality decreased interobserver disagreement and improved agreement of judgment of abnormality among evaluators. Therefore, the same clinical neurophysiologist should perform repeat NCs of therapeutic trial patients. Conclusions: Differences in interobserver judgment of abnormality decrease with use of common standard reference values and a defined percentile level of abnormality, providing a rationale for their use in therapeutic trials and medical practice. Muscle Nerve 50: 900–908, 2014