Active Head Rotation Test in Unilateral and Bilateral Peripheral Vestibulopathy

Park, Hyun Min; Kim, Young Hoon; Rhee, Chung Ku

Abstract

BACKGROUND AND OBJECTIVES: Active head rotation test measures vestibulo-ocular reflex at frequencies of 1 Hz to 8 Hz which correspond to the frequencies of head movements in daily living. However, the normative data of several authors are not in unity, and the usefulness of the test in the evaluation of the peripheral vestibulopathy is yet to be determined. The purpose of this study is to make our own normative data using our own testing condition and facilities and to evaluate the usefulness of the test in the evaluation of the peripheral vestibulopathy.
MATERIALS AND METHODS
Active head rotation test was performed in 22 controls and 34 peripheral vestibulopathy patients (24 unilateral, 10 bilateral) using the VORTEQ system in darkness with eyes open (VOR-EO). Gain, phase and symmetry were compared between the control group and the patient groups.
RESULTS
The control group showed the gain of 1.0 to 1.1 at frequencies of 1 Hz to 4 Hz. Phase was between 4 to 7 degrees, and symmetry was close to zero. Unilateral vestibulopathy group did not show a significant difference in gain, phase and symmetry from the normal group at the majority of frequencies. Bilateral vestibulopathy group showed a significant gain reduction compared to the normal group and unilateral group (p<0.05). But phase and symmetry were not significantly different.
CONCLUSION
The active head rotation test was not useful in evaluating unilateral peripheral vestibulopathy although it was useful in assessing funcitonal deficit of VOR in bilateral vestibulopathy.