Motor unit number index in children with later‐onset spinal muscular atrophy
Authors:
- 5 May 2020
- journal article
- research article
- Published by Wiley in Muscle & Nerve
- Vol. 62 (5) , 633-637
Abstract
Background: Motor unit number index (MUNIX) is a validated electrophysiological biomarker in amyotrophic lateral sclerosis. MUNIX studies in spinal muscular atrophy (SMA) are limited.Methods: Later‐onset SMA children (n = 13; three SMN2 copy number) were evaluated for Hammersmith Motor Function Scale Expanded (HMFSE) and MUNIX of right abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles. Age‐matched healthy controls (n = 8) were enrolled to obtain normative APB and ADM MUNIX values.Results: Mean APB and ADM MUNIX values in SMA subjects were significantly reduced (P < .001) compared with controls. HMFSE scores strongly correlated with ADM MUNIX (r 0.63).Conclusions: APB and ADM muscle MUNIX studies are feasible in SMA type 2 children. ADM MUNIX correlated with disease severity on motor function testing. MUNIX studies in later‐onset SMA could be a potential biomarker of motor neuron loss.Keywords
This publication has 15 references indexed in Scilit:
- Natural history of infantile‐onset spinal muscular atrophyAnnals of Neurology, 2017
- MUNIX: Reproducibility and clinical correlations in Amyotrophic Lateral SclerosisClinical Neurophysiology, 2016
- 209th ENMC International Workshop: Outcome Measures and Clinical Trial Readiness in Spinal Muscular Atrophy 7–9 November 2014, Heemskerk, The NetherlandsNeuromuscular Disorders, 2015
- Motor unit loss estimation by the multipoint incremental MUNE method in children with spinal muscular atrophy – A preliminary studyNeuromuscular Disorders, 2015
- The motor neuron response to SMN1 deficiency in spinal muscular atrophyMuscle & Nerve, 2013
- Motor Unit Number Index (MUNIX): A novel neurophysiological marker for neuromuscular disorders; test–retest reliability in healthy volunteersClinical Neurophysiology, 2011
- Motor unit number index (MUNIX): principle, method, and findings in healthy subjects and in patients with motor neuron diseaseMuscle & Nerve, 2010
- The Hammersmith Functional Motor Scale for Children with Spinal Muscular Atrophy: a Scale to Test Ability and Monitor Progress in Children with Limited AmbulationEuropean Journal of Paediatric Neurology, 2003
- Motor unit number estimation in infants and children with spinal muscular atrophyMuscle & Nerve, 2002
- Motor Nerve Conduction StudiesJournal Of Clinical Neurophysiology, 1995