AAEM PRACTICE TOPIC IN ELECTRODIAGNOSTIC MEDICINE American Association of Electrodiagnostic Medicine

At this time, there are no widely accepted criteria for the diagnosis of multifocal motor neuropathy. Furthermore, there is insufficient empirical data to define clinical and laboratory features that may reliably separate certain lower motor neuron syndromes with overlapping features as distinct. The AAEM therefore developed five criteria through a formal consensus process that are described in this document to act as a guide for diagnosing multifocal motor neuropathy with a high level of confidence (definite multifocal motor neuropathy) or with a moderate level of confidence (probable motor neuropathy). In brief, the diagnosis requires clinical weakness without objective sensory loss or upper motor neuron signs in the distribution of two or more named nerves that is due to conduction block in two or more motor nerves outside of common entrapment sites. Furthermore, normal results are required for sensory nerve conduction studies. Muscle Nerve 27: 117–121, 2003 CONSENSUS CRITERIA FOR THE DIAGNOSIS OF MULTIFOCAL MOTOR NEUROPATHY RICHARD K. OLNEY, MD, RICHARD A. LEWIS, MD, TIMOTHY D. PUTNAM, MD, and JOSEPH V. CAMPELLONE, JR., MD American Association of Electrodiagnostic Medicine, 421 First Avenue S.W., Suite 300 East, Rochester, MN 55902, USA Multifocal motor neuropathy is a disease of lower motor neurons in adults that produces asymmetrical muscle weakness, often in association with fasciculations and cramping. Although the weakness caused by this uncommon disease is reversible with certain immunomodulating treatments, multifocal motor neuropathy may be mistaken for other, far more serious, disorders such as amyotrophic lateral sclerosis (ALS) that do not respond to immunotherapy. At this time, there are no widely accepted criteria for the diagnosis of multifocal motor neuropathy. Furthermore, there is insufficient empirical data to define clinical and laboratory features that may reliably separate certain lower motor neuron syndromes with overlapping features as distinct. An expert panel of the American Association of Electrodiagnostic Medicine (AAEM) therefore developed this document to act as a guide for diagnosing the disease. DESCRIPTION OF THE PROCESS Physicians are often required to make diagnostic or therapeutic decisions for conditions in which empiric data and knowledge are incomplete or inconclusive. In such settings, the development of a consensus from an appropriate group of experts is often helpful in focusing research on critical questions and in providing interim guidance until the questions are answered empirically. Because the need for establishing consensus criteria is common, clinical health researchers have developed consensus methods over the past three decades. A five-round modified Delphi process was used to develop these consensus criteria.4 The authors wrote an initial draft document, which was circulated for unsolicited comments from an expert panel. The expert panel was chosen from AAEM members who This article was prepared and reviewed by the AAEM and did not undergo the separate review process of Muscle & Nerve. Approved by the AAEM Board of Directors, June 2002 Expert panel: Richard J. Barohn, MD; Jasper R. Daube, MD; Gerald Felsenthal, MD; Jun Kimura, MD; Richard A. Lewis, MD; Robert G. Miller, MD; Shin J. Oh, MD; Richard K. Olney, MD; Gareth J.G. Parry, MB, ChB; Austin J. Sumner, MD