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.

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

Moglia C.;
2019-01-01

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.
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Amyotrophic lateral sclerosis; Electrophysiology; Motor neuron; Motor unit; Motor unit number index; Motor unit size index; Amyotrophic Lateral Sclerosis; Electromyography; Female; Healthy Volunteers; Humans; Male; Motor Neurons; Muscle, Skeletal; Neuromuscular Diseases; Reproducibility of Results
Alix J.J.P.; 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 P.E.; Furtula J.; van Dijk J.P.; Baldinger R.; Costa J.; Otto M.; Sandberg A.; Weber M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1760967
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