Motorized head impulse rotator for horizontal vestibulo-ocular reflex: Normal responses

Area of Science:

• Neuroscience
• Ophthalmology
• Vestibular System

Background:

• The vestibulo-ocular reflex (VOR) stabilizes vision during head movements.
• Accurate VOR assessment is crucial for diagnosing vestibular disorders.
• Existing methods for VOR measurement can be time-consuming or require specialized equipment.

Purpose of the Study:

• To characterize the horizontal angular vestibulo-ocular reflex (VOR) using a novel motorized head impulse rotator and electro-oculography (EOG) technique.
• To evaluate the reliability and repeatability of this new VOR measurement system.

Main Methods:

• A prospective case-control study involving 22 healthy volunteers.
• Unpredictable, horizontal motorized head impulses were administered at high velocities and accelerations.
• Head and eye movements were recorded using EOG to calculate VOR gain, asymmetry, and latency.
• Testing was repeated for repeatability assessment, with some subjects tested on near and far visual targets.

Main Results:

• The novel system demonstrated a mean VOR gain of 1.08 +/- 0.10 for a far target.
• Mean gain asymmetry was 3.7% +/- 2.8%, and mean latency was 3.4 +/- 6.3 ms.
• Measurements showed significant repeatability (r=0.59, P=.004), and gain was higher for near targets (1.26 +/- 0.10).

Conclusions:

• The motorized head impulse rotator with EOG provides reliable and fast VOR measurements comparable to existing techniques.
• The method is safe, repeatable, and suitable for clinical assessment of the VOR.
• This novel system offers a valuable tool for evaluating vestibular function.