Comparison of manual whole-body and passive and active head-on-body rotational testing with conventional rotary chair testing.

New methods of rotational testing of the vestibulo-ocular reflex (VOR) using manually generated or patient-generated sinusoidal head movements have recently been advocated for clinical use in circumstances where conventional rotary chair testing methods are not feasible. However, studies seeking to provide evidence for the validity of these methods by comparing their results with an accepted "gold-standard" have been conspicuously absent in the literature. In this study, we compared results for VOR gain, phase, and asymmetry obtained using whole-body and head-on-body rotational stimuli with those obtained by conventional rotary chair testing in 35 subjects with either unilateral or bilateral vestibular deficits over the range of frequencies from 0.025 Hz to 1 Hz. Our results provide evidence for the validity of manual whole-body and active and passive head-on-body rotational testing methods by demonstrating excellent agreement between each of these and conventional rotational chair testing for VOR gain, phase, and asymmetry within the frequency range studied. Small differences at specific-paradigm datapoints are likely secondary to subtle limitations of our experimental design. With further refinement, we expect the new methods will be useful adjuncts for evaluating patients with vestibular complaints in selected clinical situations.