Why averaging multiple MUNIX measures in the longitudinal assessment of patients with ALS?

Why averaging multiple MUNIX measures in the longitudinal assessment of patients with ALS?

Clin Neurophysiol. 2017 Oct 04;128(12):2392-2396

Authors: Escorcio-Bezerra ML, Abrahao A, Santos-Neto D, de Oliveira Braga NI, Oliveira ASB, Manzano GM

Abstract
OBJECTIVE: To assess the impact of averaging multiple MUNIX trials on the follow-up of patients with amyotrophic lateral sclerosis (ALS).
METHODS: We determined the percent relative change (%RC) of MUNIX, in healthy subjects and patients with ALS, by subtracting the MUNIX value in the second visit from the first. Both the mean of a set of three MUNIX (mean-MUNIX) and the first MUNIX sample (single-MUNIX) were evaluated. Then, we studied the sensitivity to detect relative changes over time and the statistical dispersion of the %RC from these two parameters.
RESULTS: We found that the mean-MUNIX %RC has lower mean coefficient of variation than the single-MUNIX %RC in all muscles. The mean-MUNIX also resulted in more ALS patients with significant %RC, i.e., outside reference limits.
CONCLUSION: The mean-MUNIX resulted in less dispersed values of %RC in patients with ALS and thus, increased the precision of the technique. The mean-MUNIX resulted also in an increase in the sensitivity to track changes over time in these patients.
SIGNIFICANCE: The mean-MUNIX should be considered in any ALS follow-up study as a more reliable approach and as a way of potentially reducing the sample size needed for the study.

PMID: 29096211 [PubMed - as supplied by publisher]

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