Outward versus inward head thrusts with video-head impulse testing in normal subjects: does it matter?

Area of Science:

• Vestibular system function
• Oculomotor control
• Neuro-otology

Background:

• The video-Head Impulse Test (v-HIT) is crucial for assessing the vestibulo-ocular reflex (VOR).
• Understanding head thrust direction's impact on v-HIT efficacy is important for accurate vestibular assessment.

Purpose of the Study:

• To compare the efficacy of outward versus inward head thrusts during v-HIT.
• To determine if head thrust direction influences VOR gain measurements in healthy individuals.

Main Methods:

• Diagnostic study involving healthy subjects.
• Rapid head movements (outward and inward thrusts) were performed.
• VOR gain was measured using two distinct v-HIT devices.

Main Results:

• A statistically significant, though small, increase in VOR gain was observed with outward head thrusts.
• This minor difference may be linked to neck strain or Alexander's law effects.
• The observed differences between outward and inward thrusts were minimal.

Conclusions:

• Both outward and inward head thrusts are clinically acceptable for v-HIT.
• The slight difference in VOR gain does not preclude the use of either thrust direction in clinical practice.