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Effect of small motor unit potentials on the motor unit number estimate
Author(s) -
van Dijk Johannes P.,
Zwarts Machiel J.,
Schelhaas Helenius J.,
Stegeman Dick F.
Publication year - 2008
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.21003
Subject(s) - motor unit , amyotrophic lateral sclerosis , population , psychology , neuroscience , medicine , disease , environmental health
Small surface motor unit potentials (S‐MUPs) may have a negative influence on the variability of the motor unit number estimate (MUNE). According to published consensus criteria S‐MUPs with a negative peak amplitude smaller than 10 μV should be omitted. The effect of omitting small S‐MUPs on the MUNE was evaluated using a simulation model. The model incorporated a healthy and amyotrophic lateral sclerosis (ALS) distribution formed with real S‐MUPs. Using a random drawing process the MUNE was calculated with and without small S‐MUPs. In the healthy population 27% of all S‐MUPs were small. MUNE determined without these S‐MUPs was marginally less variable. However, MUNE values dropped about 24% at a sample size of 20. In ALS, only 12% of the total population of 130 S‐MUPs were small. MUNE dropped about 12% without the small S‐MUPs. By omitting small S‐MUPs the differences between the healthy and ALS distributions become smaller. Therefore, incorporating small S‐MUPs in the estimate is suggested. © 2008 Wiley Periodicals, Inc. Muscle Nerve, 2008