Reproducibility of the CMAP scan.
BACKGROUND
The CMAP scan is a surface EMG method based on the successive activation of motor units. It provides information about reinnervation processes, the number of functional motor units and nerve excitability. The CMAP scan has potential value as a follow-up tool in monitoring disease progression, recovery or aging of the peripheral nerves. In this study, we assessed its interobserver and different-day reproducibility.


METHODS
Two investigators recorded CMAP scans in ten healthy subjects, each on two different days. Intraclass correlation coefficients (ICCs) and coefficients of variation (CoVs) were calculated for the parameters extracted from the CMAP scan.


RESULTS
All CMAP scan parameters had a good different day (ICCs >0.8 and CoVs <15%) and interobserver reproducibility (ICCs >0.7 and CoVs ≤ 15%). Different-day reproducibility was better than interobserver reproducibility.


CONCLUSIONS
CMAP scan test-retest variability is small, suggesting that as a follow-up tool it may be sensitive to fairly small (patho)physiological changes in the studied variables.
Department of Clinical Neurophysiology, Erasmus MC, University Medical Center Rotterdam, The Netherlands. e.maathuis@erasmusmc.nl
Ellen M
EM
Maathuis
Judith
J
Drenthen
Gerhard H
GH
Visser
Joleen H
JH
Blok
D000328:Adult; D000465:Algorithms; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult