Examination of Utricular Response Using oVEMP and Unilateral Centrifugation Rotation Testing

OBJECTIVE: 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 intra-subject relationships between these measures. The study hypothesis was that intra-subject responses from oVEMP and UCF testing would be correlated inasmuch as both tests have been reported to assess utricular function. DESIGN: Unilateral centrifugation rotations and oVEMP testing were performed on healthy volunteers, aged 18–62 years. A within-subject study design compared and correlated UCF outcome measures of ocular counterroll (OCR), subjective visual vertical, and ocular counterroll gravitational inertial acceleration (GIA) 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 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.