Electromyogram (EMG) and Nerve Conduction Study (NCS) Findings in Children with Neuromuscular Disorders

Abstract

Background: An electromyogram (EMG) measures the electrical activity of muscles when they're at rest and when they're being used. On the other hand, nerve conduction study (NCS) is a medical diagnostic test used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. Both are used to diagnose the status of neuromuscular disorders even in children. Aim of the study: The aim of this study was to assess the findings of electromyogram and nerve conduction study in children with neuromuscular disorders. Methods: This retrospective, observational study was conducted in the department of Paediatric Neuroscience, Dhaka Shishu Hospital & BICH, Dhaka, Bangladesh during the period from January 2010 to December 2016. In total 65 suspected children with neuromuscular disorders were selected as the study subjects. After elaborating the history taking and physical examination a provisional diagnosis was made and sent for NCS and EMG to trained personnel at Bangladesh Protibondhi Foundation along with other necessary investigations. All data were recorded and the “clinical and etiological” profile was correlated with the neurophysiologic findings retrospectively. Results: As investigation reports of EMG, among all participants, we found normal findings in 21 participants. Besides these, a variety of SMA and/or late-onset SMA were found in 16 participants. Moreover, diffuse fibrillation, biphasic complex, repetitive spontaneous discharge was found among 6 participants. On the other hand, as per the investigation reports of NCS among all the participants, the normal finding was in 34 participants. Besides this low amplitude CMAP and SNAP, low amplitude CMAP, variable sensory conduction velocity, and slow conduction velocity with temporal dispersion were found in 3, 6, another 3, and 4 participants respectively. The compatibilities of electrophysiological diagnosis were found at 68% for detecting neurogenic disease and 71% for detecting myogenic disease. On the other hand, the compatibilities of the Nerve Conduction Study were found 46% for detecting neurogenic disease and 50% for detecting myogenic disease. Conclusion: NCS and EMG are crucial investigations to reach confirmation as well as the exclusion of the diagnosis of neuromuscular disorder in children.