Age Is a Greater Influence on Small Saccades Than Target Size in Normal Subjects on the Horizontal Video Head Impulse Test

Conclusion: While this study suggests that target size may have a statistically significant impact on the vHIT saccade profile of normal subjects, age has a greater influence on the incidence and size of small vHIT saccades. Introduction The video head impulse test (vHIT) is a quantitative adaptation of the clinical head impulse test (1), and enables functional assessment of the high-frequency angular vestibulo-ocular reflex (VOR) in all three planes of head rotation (2, 3). Lightweight goggles worn by the subject detect head movement using an accelerometer and gyroscope, and a high frame rate video camera tracks eye movement using pupil detection algorithms. Passive, small amplitude, high velocity head impulses in the planes of semi-circular canal pairs assess the ability of the VOR to generate the eye movements necessary to main visual fixation on a target. Commercially available vHIT software calculates a measure of VOR gain (the ratio of eye to head velocity), which can be compared to stratified age-related normative data to diagnose vestibular dysfunction (4). vHIT can also detect and quantify “catch-up saccades” generated by a deficient VOR. The test has a number of potential clinical uses; as a complementary and additional part of the vestibular test battery (2, 5), as a potential screening tool (6, 7), and as a front-line diagnostic test in emergency medicine to aid in the differentiation of peripheral from central causes of acute vertigo (8, 9)....
Source: Frontiers in Neurology - Category: Neurology Source Type: research