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BACKGROUND: The video head impulse test (vHIT) is a common assessment of semicircular canal function during high-speed impulses. Reliability of the vHIT for assessing vertical semicircular canals is uncertain. Vertical head impulses require a complex head movement, making it difficult to isolate a single semicircular canal and interpret resulting eye rotations. OBJECTIVE: The purpose of this study was to provide descriptive head kinematics and vestibular stimuli during vertical plane impulses to ultimately improve impulse delivery and interpretation of vHIT results for vertical semicircular canals. METHODS: Six participants received right anterior (RA) and left posterior (LP) semicircular canal impulses. Linear displacements, rotational displacements, and rotational velocities of the head were measured. Peak velocities in semicircular canal planes and peak-to-peak gravitoinertial accelerations at the otolith organs were derived from head kinematics. RESULTS: The largest rotational velocities occurred in the target semicircular canal plane, with non-negligible velocities occurring in non-target planes. Larger vertical displacements and accelerations occurred on the right side of the head compared to the left for RA and LP impulses. CONCLUSIONS: These results provide a foundation for designing protocols to optimize stimulation applied to a singular vertical semicircular canal and for interpreting results from the vHIT for vertical semicircular canals. [ABSTRACT FROM AUTHOR]

BACKGROUND: It has not yet been tested whether averaged gain values and the presence of pathological saccades are significantly altered by manual data selection or if data selection only done by the incorporated software detection algorithms provides a reliable data set following v-HIT testing. OBJECTIVE: The primary endpoint was to evaluate whether the averaged gain values of all six SCCs are significantly altered by manual data selection with two different v-HIT systems. METHOD: 120 subjects with previously neither vestibular nor neurological disorders underwent four separate tests of all six SCCs with either EyeSeeCam® or ICS Impulse®. All v-HIT test reports underwent manual data selection by an experienced ENT Specialist with deletion of any noise and/or artifacts. Generalized estimating equations were used to compare averaged gain values based on unsorted data with averaged gain values based on the sorted data. RESULTS: EyeSeeCam®: Horizontal SCCs: The estimate and the p-value (shown in parenthesis) for the right lateral SCC and the left lateral SCC were 0.00004 (0.95) and 0.00087 (0.70) respectively. Vertical SCCs: The estimate varied from –0.00858 to 0.00634 with p-values ranging from 0.31 to 0.78. ICS Impulse®: Horizontal SCCs: The estimate and the p-value for the right lateral SCC and the left lateral SCC were 0.00159 (0.18) and 0.00071 (0.38) respectively. Vertical SCCs: The estimate varied from 0.00217 to 0.01357 with p-values ranging from 0.00 to 0.17. Based upon the averaged gain value from the individual SCC being tested, 148 tests before and 127 after manual data selection were considered pathological. CONCLUSION: None of the two v-HIT systems revealed any clinically important effects of manual data selection. However, 21 fewer tests were considered pathological after manual data selection. [ABSTRACT FROM AUTHOR]