title: Enhancing the reproducibility of ocular vestibular evoked myogenic potentials by use of a visual target originating from a head-mounted laser.
abstract: Ocular vestibular evoked myogenic potentials (oVEMPs) represent extraocular muscle activity in response to vestibular stimulation. oVEMP amplitudes are known to increase with increasing upward gaze angle, while the patient fixates a visual target. We investigated two different methods of presenting a visual target during oVEMP recordings. 57 healthy subjects were enrolled in this study. oVEMPs were elicited by 500 Hz air-conducted tone bursts while the subjects were looking upward at a marking which was either fixed on the wall or originated from a head-mounted laser attached to a headband, in either case corresponding to a 35° upward gaze angle. oVEMP amplitudes and latencies did not differ between the subjects looking at the fixed marking and the ones looking at the laser marking. The intra-individual standard deviation of amplitudes obtained by two separate measurements for each subject, however, as a measure of test-retest reliability, was significantly smaller for the laser headband group (0.60) in comparison to the group looking at the fixed marking (0.96; p = 0.007). The intraclass correlation coefficient revealed better test-retest reliability for oVEMP amplitudes when using the laser headband (0.957) than using the fixed marking (0.908). Hence, the use of a visual target originating from a headband enhances the reproducibility of oVEMPs. This might be due to the fact that the laser headband ensures a constant gaze angle and rules out the influence of small involuntary head movements on the gaze angle.
authors.affiliation: German Center for Vertigo and Balance Disorders, Grosshadern Medical Center, University of Munich, Marchioninistr. 15, 81377, Munich, Germany, claudia.jerin@med.uni-muenchen.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Jerin
authors.forename: Klaus
authors.initials: K
authors.lastname: Bartl
authors.forename: Erich
authors.initials: E
authors.lastname: Schneider
authors.forename: Robert
authors.initials: R
authors.lastname: Gürkov
mesh_terms: D000328:Adult; D004576:Electromyography / Q000379:methods*; D005260:Female; D006257:Head; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D007834:Lasers; D008297:Male; D009801:Oculomotor Muscles / Q000502:physiology*; D015203:Reproducibility of Results; D058585:Vestibular Evoked Myogenic Potentials / Q000502:physiology*