Establishing high‐quality reference values for ... - …

1 AANEM TECHNOLOGY REVIEWESTABLISHING HIGH-QUALITY reference values FOR NERVECONDUCTION STUDIES: A REPORT FROM THE NORMATIVE DATATASK FORCE OF THE AMERICAN ASSOCIATION OF NEUROMUSCULAR& ELECTRODIAGNOSTIC MEDICINETIMOTHY DILLINGHAM MD,1 SHAN CHEN MD, PhD,2 MICHAEL ANDARY MD,3 RALPH BUSCHBACHER MD,4 DAVID DEL TORO MD,5 BENN SMITH MD,6 KUNO ZIMMERMANN DO, PhD,7and YUEN SO MD81 Department of Physical Medicine and Rehabilitation, University of Pennsylvania, 1800 Lombard Street, First Floor, Philadelphia,Pennsylvania 19146, USA2 Department of Neurology, Rutgers, the State University of New Jersey.

2 Robert Wood Johnson Medical School, New Brunswick, NewJersey, USA3 Department of Physical Medicine and Rehabilitation, College of Osteopathic Medicine, Michigan State University, East Lansing,Michigan, USA4 Department of Physical Medicine and Rehabilitation, Indiana University, Indianapolis, Indiana, USA5 Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin, Milwaukee, Wisconsin, USA6 Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA7 Qinqunxx Institute, Rosharon, Texas, USA8 Department of Neurology, Stanford University, Stanford, California, USAA ccepted 26 May 2016 ABSTRACT:Introduction:There are not uniform standards fornerve conduction testing across the United States.

3 The objective ofthis study is to present a set of methodologically sound criteria toevaluate the literature for the purpose of identifying high-quality nor-mative nerve conduction studies (NCS) suitable for :The Normative Data Task Force (NDTF) wasformed to review published studies on methodological issuesrelated to NCS. A set of criteria was then developed to evaluatethe literature. These criteria and their rationale are :We identified 7 key issues that reflect high quality in each issue, specific review criteria were :Rigorous criteria enable identification of high-quality studiesdealing with nerve conduction reference values .

4 This representsthe first step toward the overarching goal of recommending NCStechniques and reference values for electrodiagnostic Nerve54: 366 370, 2016 Electrodiagnostic (EDx) medicine has been in exis-tence since the 1940s. EDx physicians and technolo-gists perform nerve conduction studies (NCS) andneedle electromyography to evaluate disorders of theperipheral nervous and musculoskeletal systems. Inthe past few decades, EDx instrumentation and sig-nal processing have benefitted greatly from techno-logical advancements in computing and American Association of Neuromuscular &Electrodiagnostic Medicine (AANEM) has beeninvolved in standardizing how the specialty is prac-ticed through publication of guidelines and recent accreditation of EDx labo-ratories is one step in standardizing and definingquality care across the field.

5 However, there is nouniversal standard for NCS in the United laboratories have historically beenencouraged to derive their own reference valuesdespite inherent methodological and statistical chal-lenges with this approach. The majority of EDxphysicians and laboratories, rather than developtheir own reference values , instead rely on the peer-reviewed literature, textbooks, or reference valuesgenerated by academic training programs. However,many published studies do not meet contemporarystandards for statistical and methodological ,4 Performing NCS on nerves and decidingwhether the results fall within an expected rangeof normal values with a statistical level of precisionis fundamental to EDx medicine.

6 Lack of NCSstandardization diminishes reliability and consis-tency in identification of concerns were demonstrated in a recentstudy that assessed intra- and interobserver reliabil-ity when patients with diabetic sensorimotor poly-neuropathy were was a in the interobserver judgment of indi-vidual nerves as being normal, which was attrib-uted to variability in the performance of NCS andin the use of varied reference values . This variabili-ty was of sufficient magnitude to be a concern fortherapeutic trials.

7 One recommendation toimprove interrater reliability in therapeutic trialsAbbreviations:AANEM American Association of Neuromuscular & Elec-trodiagnostic Medicine, EDx, electrodiagnostic; MSE, mean square error;NCS, nerve conduction studies; NDTF, Normative Data Task Force;SNAP, sensory nerve action potentialKey words:erve conduction; nerve conduction studies; normal values ;normative data; reference values ; standards of practice; guidelinesDisclaimer: This article was prepared and reviewed by the American Asso-ciation of Neuromuscular & Electrodiagnostic Medicine (AANEM) and didnot undergo separate peer review at Muscle & Nerve.

8 Reviewed by theAANEM Practice Issue Review Panel, April 2016. Approved by the AANEMB oard of Directors in April Dillingham; e-mail: American Association of Neuromuscular and ElectrodiagnosticMedicinePublished online in Wiley Online Library ( ). DOI Technology ReviewMUSCLE & NERVE September 2016was strict standardization of NCS acompanion study by the same research group,institution of standard instructions, techniques,procedures, and reference values led to betterinterobserver judgment of AANEM formed the Normative Data TaskForce (NDTF)

9 In 2011 to examine how NCS areperformed and to assess the scientific underpin-nings of these clinical techniques, with the goal offinding the best reference values for clinical nerveconduction initial charge for the NDTF was to derive aframework for systematically evaluating the pub-lished literature. The rationale, criteria, and meth-odology for assessing the published literature arepresented NDTF evaluated published methodologicalstudies relevant to conducting NCS and derivingreference values . These studies and the insightsfrom NDTF members led to the development of 7criteria (Table 1).

10 The rationale for each criterionis described below and provides the framework forsystematic evaluation of the NCS of differences betweenolder analog EMG machines and moderncomputer-based digital equipment, the NDTF focused on works published after 1990, whichmore likely reflect studies conducted using mod-ern equipment. Literature searches used the terms nerve conduction or nerve conduction studies and the name or names of the nerves under inves-tigation in the following databases: PubMed/Med-line; EMBASE; Web of Science; and Sample sample sizes increasepower and precision and are important for norma-tive data studies, because the upper or lower limitsof the underlying distribution are significantlyinfluenced by extreme values (outliers).