Normative data on angular vestibulo-ocular responses in the yaw axis measured using the video head impulse test

Area of Science:

• Otolaryngology
• Neuroscience
• Vestibular System Research

Background:

• The vestibulo-ocular reflex (VOR) is crucial for maintaining gaze stability during head movements.
• Age-related changes in the vestibular system can impact VOR function.
• The video head impulse test (vHIT) is a valuable tool for assessing VOR performance.

Purpose of the Study:

• To analyze vestibulo-ocular responses in the yaw axis using the video head impulse test (vHIT).
• To investigate the influence of age, sex, and head impulse velocity on VOR gain and refixation saccades (RSs).

Main Methods:

• Prospective study conducted in a tertiary and university hospital setting.
• 212 healthy subjects underwent vHIT in the plane of the lateral semicircular canal.
• VOR gain and the presence of RSs were recorded and analyzed in relation to age, sex, and head impulse velocity.

Main Results:

• Mean VOR gain was 1.06 ± 0.07, with no sex differences.
• VOR gain decreased with increasing head impulse velocity across all subjects.
• VOR gain remained stable until age 70 for high-velocity impulses and until age 90 for low-velocity impulses.
• Refixation saccades (RSs) were observed in 52 subjects, predominantly in those over 71 years old.
• Head impulse velocity, not age, correlated with the presence of RSs.

Conclusions:

• VOR gain is generally stable until age 90, after which it declines.
• Faster head impulses lead to a progressive decrease in VOR gain, particularly in individuals over 70.
• The increased incidence of RSs and VOR gain changes with age suggest age-related deterioration of the vestibular system's semicircular canals.