title: Motor unit loss estimation by the multipoint incremental MUNE method in children with spinal muscular atrophy--a preliminary study.
abstract: Quantitative EMG reflects denervation of muscles after lower motor neuron degeneration in spinal muscular atrophy (SMA) but does not reflect actual motor unit loss. The aim of our study was to assess the value of the multipoint incremental motor unit number estimation (MUNE) method in the modification by Shefner in estimating motor unit loss in SMA. The number of motor units, the mean amplitude of an average surface-detected single motor unit potential (SMUP), and the amplitude of compound motor action potentials (CMAP) were estimated in 14 children with SMA in the abductor pollicis brevis (ABP). Significant differences in MUNE values and SMUP and CMAP amplitude were found between the SMA and control groups (P < 0.0001). MUNE values correlated with Hammersmith Functional Motor Scale (HFMS) scores (P < 0.05). Increased SMUP amplitude values correlated with decreased HFMS scores (P < 0.05). The study confirms that MUNE method in the modification by Shefner is a useful tool reflecting motor unit loss in SMA, and it is easy to perform and well tolerated. MUNE and SMUP amplitude seemed to be sensitive parameters reflecting motor dysfunction in SMA but a longitudinal study in a larger number of subjects is needed.
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland. Electronic address: mgawel@wum.edu.pl.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Gawel
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kostera-Pruszczyk
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Lusakowska
authors.affiliation: Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Jedrzejowska
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Ryniewicz
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Lipowska
authors.affiliation: Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, 99/103 Marymoncka Street, 01-813 Warsaw, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Gawel
authors.affiliation: Department of Neurology, Medical University of Warsaw, 1A Banacha Street, 02-097 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kaminska
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000293:Adolescent; D000328:Adult; D002648:Child; D004576:Electromyography / Q000379:methods*; D005260:Female; D006225:Hand / Q000503:physiopathology; D006801:Humans; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009134:Muscular Atrophy, Spinal / Q000175:diagnosis / Q000503:physiopathology*; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: MUNE; Motor unit; Motor unit number estimation; Spinal muscular atrophy