Macro-EMG and inflammatory myopathies European Journal of Translational Myology pISSN: 2037-7452 eISSN: 2037-7460 https://www.pagepressjournals.org/index.php/bam/index Publisher's Disclaimer. E-publishing ahead of print is increasingly important for the rapid dissemination of science. The Early Access service lets users access peer-reviewed articles well before print / regular issue publication, significantly reducing the time it takes for critical findings to reach the research community. These articles are searchable and citable by their DOI (Digital Object Identifier). The European Journal of Translational Myology is, therefore, e-publishing PDF files of an early version of manuscripts that undergone a regular peer review and have been accepted for publication, but have not been through the typesetting, pagination and proofreading processes, which may lead to differences between this version and the final one. The final version of the manuscript will then appear on a regular issue of the journal. E-publishing of this PDF file has been approved by the authors. Eur J Transl Myol 2025 [Online ahead of print] To cite this Article: Finsterer J. CN-macroEMG does not provide additional support for diagnosing inflammatory myopathies. Eur J Transl Myol doi: 10.4081/ejtm.2025.14239 ©The Author(s), 2025 Licensee PAGEPress, Italy Note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries should be directed to the corresponding author for the article. All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. https://www.pagepressjournals.org/index.php/bam/index https://www.pagepress.org/site Macro-EMG and inflammatory myopathies CN-macroEMG does not provide additional support for diagnosing inflammatory myopathies Josef Finsterer Neurology Department, Neurology & Neurophysiology Center, Vienna, Austria Key words: idiopathic inflammatory myopathies, macro-EMG, concentric needle electrodes, myositis, sensitivity/specificity. We read with interest the article by ElZamarany et al. on a case-control study of the use of concentric needle macroelectromyography (CN-macroEMG) in 26 patients with Inflammatory Myopathies (IM) and 20 healthy control subjects.1 The study concludes that CN macroEMG provides optimal results in the diagnosis of IM and can be helpful in the follow- up of IM patients.1 The study is impressive, but some points should be discussed. The first point is that the objectives of the study were not specified.1 We should know whether the study was conducted to calculate the sensitivity and specificity of the method for diagnosing IM, or simply to document that CN-macroEMG may be abnormal in patients with IM. If the aim was to calculate sensitivity/specificity, we should know which gold standard for the diagnosis of IM was used to compare it with the CN-macroEMG findings. The second point is that factors determining the CN-macroEMG signal were not sufficiently included in the analysis.1 The CN-macroEMG signal depends not only on the type of underlying IM (polymyositis, dermatomyositis, immune-mediated necrotizing myositis, overlap syndromes, including anti-synthetase syndrome), but also on the muscle examined, the treatment used for IM, and the stage or duration of the disease.2 As long as these influencing factors are not sufficiently taken into account in the analysis of the data, the results may remain unreliable. The third point is that EMG is generally of limited importance for the diagnostic evaluation of IM. The diagnosis of IM is usually made on the basis of medical history, symptoms and signs, blood tests, the determination of myositis-associated and myositis-specific antibodies, a muscle MRI with contrast agent, and a muscle biopsy. What criteria and methods were used to diagnose IM in the 26 patients included in the study? Macro-EMG and inflammatory myopathies The fourth point is that it is unclear why patients with viral myositis were included in the analysis.1 Viral myositis is classified as infectious myositis, not idiopathic IM. Therefore, these patients should be excluded from the evaluation. The fifth point is that we disagree with the view that IM is generally characterized by weakness of the proximal muscles.1 Although certain muscle groups may be predominantly affected in some patients, muscle weakness in IM can generally occur in all striated muscles.3 We also disagree with the view that IM is generally associated with muscle pain. IM is known to cause muscle weakness without myalgia.4 Finally, due to the unequal group sizes (26 vs. 20), it is not possible to match the study group with the control group in terms of age and gender. Overall, CN-macroEMG is of limited value for the diagnostic evaluation of IM. To assess whether it has additional benefits over CN EMG, it should be compared with this technique or a gold standard in terms of its sensitivity and specificity in homogeneous groups of IM. Corresponding author Josef Finsterer, Neurological Department, Neurology and Neurophysiolgy Center, Postfach 20, 1180 Vienna, Austria. Tel. +43-1-5861075 Fax. +43-1-5861075 E-mail: fifigs1@yahoo.de Conflict of interest The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethical approval and consent to participation Not applicable Funding None received mailto:fifigs1@yahoo.de Macro-EMG and inflammatory myopathies Availability of data and material All data are available from the corresponding author. References 1. ElZamarany E, Farouk AA, Afifi L, et al. Concentric macro EMG role in electrodiagnostic evaluation of inflammatory myopathies. Eur J Transl Myol 2025 Jul 15. doi: 10.4081/ejtm.2025.13833. 2. Gutiérrez-Gutiérrez G, Barbosa López C, Navacerrada F, Miralles Martínez A. Use of electromyography in the diagnosis of inflammatory myopathies. Reumatol Clin 2012;8:195-200. 3. Selva-O'Callaghan A, Pinal-Fernandez I, Trallero-Araguás E, et al. Classification and management of adult inflammatory myopathies. Lancet Neurol 2018;17:816-28. 4. Oldroyd A, Lilleker J, Chinoy H. Idiopathic inflammatory myopathies - a guide to subtypes, diagnostic approach and treatment. Clin Med (Lond) 2017;17:322-8.