Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings

James J.P. Alix (Corresponding author), Christoph Neuwirth, Lucy Gelder, Christian Burkhardt, José Castro, Mamede de Carvalho, Malgorzata Gawel, Stephan Goedee, Julian Grosskreutz, Timothée Lenglet, Cristina Moglia, Taha Omer, Maarten Schrooten, Sanjeev Nandedkar, Erik Stalberg, Paul E. Barkhaus, Jasna Furtula, Johannes P. van Dijk, Reto Baldinger, Joao CostaMarit Otto, Arne Sandberg, Markus Weber

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

2 Citaten (Scopus)


OBJECTIVE: The motor unit size index (MUSIX) is incorporated into the motor unit number index (MUNIX). Our objective was to assess the intra-/inter-rater reliability of MUSIX in healthy volunteers across single subject "round robin" and multi-centre settings.

METHODS: Data were obtained from (i) a round-robin assessment in which 12 raters (6 with prior experience and 6 without) assessed six muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis and abductor hallucis) and (ii) a multi-centre study with 6 centres studying the same muscles in 66 healthy volunteers. Intra/inter-rater data were provided by 5 centres, 1 centre provided only intra-rater data. Intra/inter-rater variability was assessed using the coefficient of variation (COV), Bland-Altman plots, bias and 95% limits of agreement.

RESULTS: In the round-robin assessment intra-rater COVs for MUSIX ranged from 7.8% to 28.4%. Inter-rater variability was between 7.8% and 16.2%. Prior experience did not impact on MUSIX values. In the multi-centre study MUSIX was more consistent than the MUNIX. Abductor hallucis was the least reliable muscle.

CONCLUSIONS: The MUSIX is a reliable neurophysiological biomarker of reinnervation.

SIGNIFICANCE: MUSIX could provide insights into the pathophysiology of a range of neuromuscular disorders, providing a quantitative biomarker of reinnervation.

Originele taal-2Engels
Pagina's (van-tot)666-674
Aantal pagina's9
TijdschriftClinical Neurophysiology
Nummer van het tijdschrift5
StatusGepubliceerd - mei 2019


Bibliografische nota

Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Citeer dit

Alix, J. J. P., Neuwirth, C., Gelder, L., Burkhardt, C., Castro, J., de Carvalho, M., ... Weber, M. (2019). Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings. Clinical Neurophysiology, 130(5), 666-674.