Single fiber EMG guidelines: Moving towards a “single” methodological consensus


Single Fiber EMG (SFEMG) has become a cornerstone tool to explore the safety factor of neuromuscular transmission and muscle physiology, enriching the armamentarium of clinical neurophysiologists during the last 40”¯years. Back in 1967, Jan Ekstedt and Erik Stålberg developed an electrode to record action potentials from single muscle fibers (SFAPs), while exploring the physiology of muscle fatigue. This technical advancement allowed them to study two physiological properties of the muscle: (i) the jitter phenomenon and (ii) the muscle fiber action potential propagation velocity (Ekstedt, 1964, Ekstedt et al., 1969). After that, many investigators and clinicians, led by Prof. Erik Stålberg, Prof. Jože V. Trontelj and Prof. Donald B. Sanders, improved this technique and explored its clinical utility in many neuromuscular diseases. Their knowledge and experience were captured in the book, Single Fibre Electromyography, which already has three editions (Stålberg et al., 2010). Moreover, the technological developments during these years have been crucial for SFEMG translation from the basic research field into clinical neurophysiology laboratories. One important advancement leading to a wider and cheaper application of the technique is the standardization of SFEMG with concentric needle electrode (CNE) (Stålberg and Sanders, 2009). Initially this variation of the technique emerged due to the restrictions on the use of reusable materials in many countries. Today, CNE has practically replaced SFEMG electrodes (SFE) to measure jitter. In fact, with a concentric needle it is not really a “single fiber” recording but a multiple fibers recording, but normal values and a standard technique have been stablished (Stålberg et al., 2016). Nowadays, common EMG equipment includes technical features such as signal trigger and signal delay, which is fundamental for jitter recording, and most of them also include the software necessary for the application of SFEMG. This is another element that has contributed to the diffusion of the technique. The wider use of a still “new” technique in many different centers around the world has the risk of generating different application methods, as well as different normal and pathological criteria....

José Manuel Matamala ,Renato J.Verdugo

Clinical Neurophysiology

mayo 07, 2019

DOI: 10.1016/j.clinph.2019.04.610

Investigador BNI: Dr. José Manuel Matamala (MD, PhD)