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Testing of all Six Semicircular Canals with Video Head Impulse Test Systems
Published on: April 18, 2019
Inter-ocular differences of the horizontal vestibulo-ocular reflex during impulsive testing.
Konrad P Weber1, Swee T Aw, Michael J Todd
1Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia. konrad.weber@bluewin.ch
Progress in Brain Research
|August 23, 2008
Summary
Accurate vestibulo-ocular reflex (VOR) testing requires measuring both eyes. Differences in VOR gain between eyes emerge at high head accelerations, necessitating binocular recording for precise VOR gain assessment.
Area of Science:
- Neuroscience
- Ophthalmology
- Vestibular System
Background:
- The vestibulo-ocular reflex (VOR) stabilizes gaze during head movements.
- Impulsive testing is a standard method for measuring VOR gain.
- Current VOR testing often relies on monocular recordings.
Purpose of the Study:
- To investigate inter-ocular differences in horizontal VOR gain during high-acceleration head impulses.
- To determine the impact of head acceleration on VOR gain symmetry.
- To evaluate the necessity of binocular recording for accurate VOR assessment.
Main Methods:
- Horizontal VOR gain was measured in both eyes of 14 healthy subjects.
- Subjects underwent graded velocity head impulses.
- VOR responses were analyzed for latency and acceleration differences between eyes.
Main Results:
- At low accelerations, VOR gains were similar between eyes.
- At high accelerations, the adducting eye showed greater VOR gain than the abducting eye.
- Inter-ocular gain differences averaged 15.3% at high accelerations, leading to directional asymmetry when only one eye was analyzed.
Conclusions:
- High-acceleration head impulses reveal significant inter-ocular VOR gain differences.
- Monocular VOR analysis can lead to inaccurate, directionally asymmetric gain measurements.
- Binocular recording is essential for precise VOR gain assessment, especially at high accelerations.
