Publication:

Does vestibulo-ocular reflex gain measured by video head impulse test decrease with age?

Backgrounds: The Video Head Impulse Test (vHIT) is used to test the function of each of the six semicircular canals. Each semicircular canal is tested by measuring eye rotation in response to head movements in the plane of the canal and is calculated as the Vestibulo-ocular reflex (VOR) gain. The aims of the study were firstly, to determine age-dependent normative values of VOR gain for the vHIT of semicircular canal function in healthy Asian subjects in each decade year of life. Secondly, to investigate if vHIT measured VOR gain decreases with age.

Methods A prospective cohort study of 60 healthy voluntary community-dwelling subjects, between 21 to 80 years of age. Subjects with prior history of vertigo were excluded. vHIT was conducted on each subject and analysed with the Interacoustics (EyeSeeCam) video goggles by the senior audiologist. The VOR gain for all six semicircular canals were calculated for each subject.

Results The mean (SD) vHIT (VOR) gain of all the 6 semicircular canals for the entire population were 1.18 (0.19). The mean of the VOR gain for each of the six semicircular canals were analysed to develop a normative guide. The mean VOR gain per decade year did not vary significantly with age (p=0.417). The correlation between age and mean VOR values was negligible (pearson’s r=0.121).

Conclusions We propose that our normative age-dependent data guide be used to improve the differentiation between normal and abnormal values of VOR gain in an Asian population. Our study shows that VOR gain is not associated with aging.