Evaluating vestibulo-ocular reflex gain characteristics with monocular video head impulse test across different age groups in a healthy population

Abstract

Objective

The study aims to assess the high-frequency Vestibulo-Ocular Reflex (VOR) gain across three pairs of semicircular canals using the EyeSeeCam device and to determine normative values.

Methods

A total of 105 volunteers, aged 19 to 69 years with no history of vestibular disorders, were enrolled. This cohort included 50 males (mean age 41.11 ± 15.98) and 55 females (mean age 35.52 ± 15.07), with no statistically significant age difference between the genders (P = 0.078). Participants were categorized into six age brackets: 11–20, 21–30, 31–40, 41–50, 51–60, and 61–70. For each test, the recording device was consistently positioned on the left side of the goggles, and the tests were conducted by a right-handed operator.

Results

The average regression gain for left anterior-right posterior canals (LARP) was 1.44 ± 0.19, significantly surpassing that of right anterior-left posterior canals (RALP) at 1.09 ± 0.13 (p < 0.001) and horizontal semicircular canals (HSC) at 1.11 ± 0.07 (p < 0.001). No significant difference was observed between the VOR gains of RALP and HSC (p = 0.1077). Additionally, VOR gain values did not show significant variation across different age groups. In a gender-based analysis, a marginally higher HSC gain was observed in females (1.13 ± 0.07) compared to males (1.11 ± 0.07; p = 0.042), while no significant gender disparity was noted for RALP gains (females: 1.09 ± 0.11; males: 1.10 ± 0.14; p = 0.641). Females exhibited significantly higher LARP gain values (1.49 ± 0.18) than males (1.41 ± 0.20; p = 0.002).

Conclusion

This study underscores the stability of high-frequency VOR gain values across ages. However, it also reveals a significant asymmetry in vertical canal gains (LARP vs RALP), suggesting a possible vertical canals monocular directional preponderance. This finding highlights that normative values can be highly specific to the recording and testing protocol. Thus, laboratories should develop their own normative values, customized to their equipment and testing protocols.