Examination of Utricular Response Using oVEMP and Unilateral Centrifugation Rotation Testing

Objectives: Significant advancements have been made toward the clinical assessment of utricular function through ocular vestibular-evoked myogenic potentials (oVEMP) and unilateral centrifugation (UCF) testing. To date, no study has examined intrasubject relationships between these measures. The study hypothesis was that intrasubject responses from oVEMP and UCF testing would be correlated inasmuch as both tests have been reported to assess utricular function. Design: UCF rotations and oVEMP testing were performed on healthy volunteers, aged 18 to 62 years. A within-subject study design compared and correlated UCF outcome measures of ocular counterroll, subjective visual vertical, and ocular counterroll–gravitational inertial acceleration slope against peak to peak oVEMP N1–P1 amplitude. Results: Correlational analyses failed to reveal any significant relationships between oVEMP amplitude and UCF responses suggesting that these tests may be inciting different response properties within the utricular system. Conclusions: Various anatomical and physiological differences within the utricle, in addition to the fundamental differences in stimulus properties between the oVEMP and UCF tests, could explain the lack of significant correlations between these measures and suggest that oVEMP and UCF testing may be complimentary in their evaluation of the utricular system. These data reinforce the complexities of the utricular system and provide further insight into the difficulties encountered in its clinical assessment. ACKNOWLEDGMENTS: The authors thank Robert Wesley, PhD (National Institutes of Health [NIH]), and Dante Picchioni, PhD (NIH), for statistical guidance; Alex Kiderman, PhD (Neuro Kinetics, Inc.), for technical and engineering support; and Susannah Wargo, DNP (NIH), for clinical support. The authors also thank Tracy Fitzgerald, PhD, and Chris Platt, PhD, from the National Institute on Deafness and Other Communication Disorders (NIDCD) for their careful review of the article and to the healthy participants for their participation in this research. This research was supported by intramural research funds from the National Institute on Deafness and Other Communication Disorders (DC000064 to C.C.B.) (Bethesda, MD) and a US Office of Special Education Programs (OSEP) leadership preparation grant (Gallaudet University, DC). Christopher Zalewski contributed to the study concept and study design, study recruitment, data collection, data analysis, statistical analysis, and writing of the article. R. Steven Ackley contributed to the study design review and data analysis review. Carmen C. Brewer, contributed to the study concept and methodology review, statistical analysis review, article review and editing. Devin L. McCaslin contributed to the study concept and methodology review, statistical analysis review, article review and editing. M. Diane Clark, contributed to the study concept and methodology review, statistical analysis review, and article review and editing. Wendy D. Hanks contributed to the study concept and methodology review, statistical analysis review, article review and editing. The primary author, Dr. Christopher K. Zalewski, takes full responsibility for the data, the analyses and interpretation, and the conduct of the research; has full access to all of the data; and that he has the right to publish any and all data separate and apart from any sponsor. The Methods section includes a statement that an Institutional Review Board or regional review board has approved the use of human subjects for this study. This is a prospective study for which the author has received consent forms from all participants in this study and has them on file in case they are requested by the editor. Address for correspondence: Christopher K. Zalewski, National Institutes of Health (NIDCD), 9000 Rockville Pike, Building 10, Room 5C422, Bethesda, MD, USA. E-mail: zalewski@nidcd.nih.gov Received March 24, 2017; accepted November 29, 2017. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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