Matthew C Pitt1, Joe F Jabre2. 1. Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK. 2. Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
Abstract
INTRODUCTION: The diagnosis of myasthenia gravis in very young infants is a challenging one. In young infants, stimulated single-fiber electromyography (StimSFEMG) is the most appropriate technique, but it has serious limitations due to the absence of reference values in this subpopulation. Here we present our efforts to derive a reference range of jitter in a patient cohort of infants <3 years of age using the extrapolated norms, or e-norms, technique. METHODS: The e-norms method was used to calculate jitter mean consecutive difference (MCD) descriptive statistics for children <3 years of age. RESULTS: The e-norms derived jitter upper MCD limit was 45 μs in children <1 year, 33 μs in those <2 years, and 26 in those <3 years of age. CONCLUSION: In the absence of jitter reference values for the very young, the e-norms method can be used as an alternative to derive these values from laboratory cohorts. Muscle Nerve 55: 51-54, 2017.
INTRODUCTION: The diagnosis of myasthenia gravis in very young infants is a challenging one. In young infants, stimulated single-fiber electromyography (StimSFEMG) is the most appropriate technique, but it has serious limitations due to the absence of reference values in this subpopulation. Here we present our efforts to derive a reference range of jitter in a patient cohort of infants <3 years of age using the extrapolated norms, or e-norms, technique. METHODS: The e-norms method was used to calculate jitter mean consecutive difference (MCD) descriptive statistics for children <3 years of age. RESULTS: The e-norms derived jitter upper MCD limit was 45 μs in children <1 year, 33 μs in those <2 years, and 26 in those <3 years of age. CONCLUSION: In the absence of jitter reference values for the very young, the e-norms method can be used as an alternative to derive these values from laboratory cohorts. Muscle Nerve 55: 51-54, 2017.