Size does matter: the influence of motor unit potential size on statistical motor unit number estimates in healthy subjects

J.H. Blok, J.P. van Dijk, J. Drenthen, E.M. Maathuis, D.F. Stegeman

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

8 Citaten (Scopus)

Samenvatting

OBJECTIVE: The statistical method of motor unit number estimation (MUNE) assumes that all motor unit potentials (MUPs) have the same size. The present study aims to evaluate the consequences of this assumption as well as its implications for the validity of statistical MUNEs.

METHODS: We performed statistical and multiple point stimulation (MPS) MUNE with an array of 120 electrodes on the thenar muscles of 15 healthy subjects. These recordings allow isolation and quantification of the effect of non-uniform MUP size on MUNE, because the differences in submaximal CMAP size (and, hence, in MUNE) between electrodes are due almost entirely to differences in (summed) MUP size.

RESULTS: We found no correlation between statistical and MPS MUNEs. Statistical MUNEs proved very sensitive to small variations in the "bandwidth" (variance) of the response series; MUNEs from electrodes only 8mm apart could deviate by as much as 60%. This variation in bandwidth resulted from spatial (and, hence, size) differences between the contributing MUPs.

CONCLUSIONS: Statistical MUNEs are very sensitive to violation of the uniform MUP-size assumption, to an extent that blurs any correlation with MPS MUNE in healthy subjects.

SIGNIFICANCE: Statistical MUNE cannot be used to detect mild to moderate motor unit losses.

Originele taal-2Engels
Pagina's (van-tot)1772-1780
Aantal pagina's9
TijdschriftClinical Neurophysiology
Volume121
Nummer van het tijdschrift10
DOI's
StatusGepubliceerd - okt 2010
Extern gepubliceerdJa

Bibliografische nota

Copyright 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

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