Vestibular evoked myogenic potentials: test-retest reliability and normative values obtained with a feedback method for the sternocleidomastoid muscle contraction.
OBJECTIVE
To determine normal limits and to analyse the test-retest reliability of the vestibular evoked myogenic potentials (VEMPs) parameters.


METHODS
The VEMP procedure was repeated on different test days to analyze test-retest differences. We calculated several reliability parameters: intraclass reliability coefficient (ICC), method error (ME), coefficient of variation of the method error (CV(ME)), standard error of measurement (SEM) and minimal difference (MD) for test-retest measurements. Normal values for left-right differences, based on the interaural ratio (IAR), were determined.


RESULTS
For each VEMP parameter, the ICC values indicated excellent reliability, except for p13 and corrected amplitude (fair to good reliability). The CV(ME)) values were less than 7% for p13, n23, threshold, MRV(females) and MRV(males). For the parameters corrected amplitude and raw amplitude, the CV(ME)) values exceeded 15%. The 95% IAR prediction intervals (PIs) were also largest for the parameters raw amplitude and corrected amplitude.


CONCLUSIONS
In order to evaluate a VEMP outcome in a patient, the VEMP parameters and IAR values can be compared with the 95% PI of the normal values. When successive measurements are performed within the same subjects, the minimal difference (MD) serves as a tool to decide whether these differences are clinically relevant or not.
Vanspauwen
R
R
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital, Antwerp University Research Center for Equilibrium and Aerospace, University of Antwerp, Wilrijkstraat 10, Edegem, Antwerpen, Belgium. robby.vanspauwen@gmail.com
Wuyts
F L
FL
Van de Heyning
P H
PH
D000328:Adult; D004576:Electromyography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology; D005246:Feedback; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D009119:Muscle Contraction; D009334:Neck Muscles / Q000502:physiology*; D015203:Reproducibility of Results; D014724:Vestibular Function Tests / Q000379:methods; D014722:Vestibule, Labyrinth / Q000502:physiology