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Improving the Reliability of V-Wave Responses in the Soleus Muscle

Mendonca, Goncalo V.*,†; Teodósio, Carolina*; Mouro, Miguel*; Freitas, Sandro*,†; Mil-Homens, Pedro*,†; Pezarat-Correia, Pedro*,†; Vila-Chã, Carolina‡,§

Journal of Clinical Neurophysiology: March 2019 - Volume 36 - Issue 2 - p 97–103
doi: 10.1097/WNP.0000000000000560
Original Research

Purpose: The V wave is an electrophysiologic variant of the H reflex that is evoked with supramaximal stimulus intensity. In this study, we explored whether the between-day reliability of V-wave normalized amplitude varies as a function of the number of intrasession measurement trials. We also determined whether the reliability of the V wave improves after the exclusion of the initial testing trials.

Methods: Eighteen healthy, young participants (10 men and 8 women) were included in this study. Test–retest reliability was assessed using intraclass correlation coefficients and the standard error of the measurement (1.96*SEM).

Results: The intraclass correlation coefficient values of the V-wave normalized amplitude increased in a progressive fashion with the inclusion of more than two measurement trials (from 0.41 to 0.75). The 1.96*SEM scores also decreased from 12.47% to 7.60% after calculating the V-wave normalized amplitude from five versus two measurement trials. After excluding the first two trials from V-wave calculations, the intraclass correlation coefficient and the 1.96*SEM score attained values of 0.88 and 6.54%, respectively.

Conclusions: Our findings indicate that the test–retest reliability of the V-wave response increases in a progressive fashion with more than two intrasession measurement trials (up to five trials). It also shows that to ensure maximal reliability, the first two measurement trials should be discarded from V-wave computations.

*Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Portugal, Estrada da Costa, Cruz Quebrada, Dafundo, Portugal;

CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Portugal, Estrada da Costa, Cruz Quebrada, Dafundo, Portugal;

Polytechnic Institute of Guarda, Av. Dr. Francisco Sá Carneiro, Portugal; and

§Research Center in Sports Sciences, Health and Human Development (CIDESD), Vila-Real, Portugal.

Address correspondence and reprint requests to Goncalo V. Mendonca, PhD, Estrada da Costa, Cruz Quebrada, 1495-688 Cruz Quebrada Dafundo, Lisboa, Portugal; e-mail:

The authors have no conflicts of interest to disclose.

Supported by the Foundation for Science and Technology (FCT), Portugal (PTDC/DTP-DES/5714–2014).

© 2019 by the American Clinical Neurophysiology Society