Faculty Collaboration Database

Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings. Clin Neurophysiol 2019 May;130(5):666-674

Date

03/15/2019

Pubmed ID

30870802

DOI

10.1016/j.clinph.2019.01.020

Scopus ID

2-s2.0-85062708417 (requires institutional sign-in at Scopus site)   14 Citations

Abstract

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.

Author List

Alix JJP, Neuwirth C, Gelder L, Burkhardt C, Castro J, de Carvalho M, Gawel M, Goedee S, Grosskreutz J, Lenglet T, Moglia C, Omer T, Schrooten M, Nandedkar S, Stalberg E, Barkhaus PE, Furtula J, van Dijk JP, Baldinger R, Costa J, Otto M, Sandberg A, Weber M

Author

Paul E. Barkhaus MD Professor in the Neurology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amyotrophic Lateral Sclerosis
Electromyography
Female
Healthy Volunteers
Humans
Male
Motor Neurons
Muscle, Skeletal
Neuromuscular Diseases
Reproducibility of Results