Assessment of Semicircular Canal Functioning Using a Video Head Impulse Test in Individuals with Occupational Noise Exposure.

Abstract

Background: Exposure to noise or loud sound damages the cochlea and can result in hearing loss, which has been well-documented. Research over the years has shown that individuals exposed to noise for a short or extended period may develop vestibular problems. The otolith organs are found to be more susceptible to noise exposure or acoustic trauma than the semicircular canals (SCC). Nonetheless, little is known about the functioning of all three SCC in individuals exposed to noise. A technologically advanced, noninvasive, simple, and fast tool, the video head impulse test (vHIT) helps in evaluating the functioning of all six SCC in three planes.Purpose of the Study: We assessed the functioning of SCC using the vHIT paradigm in individuals with and without noise exposure.Research Design: The study used a quasi-experimental, between-groups design.Study Sample: The study included15 individuals with occupational noise exposure for at least 5 years (clinical group) and 15 individuals without noise exposure (control group) aged 30 to 55 years.Data Collection and Analysis: The vHIT was administered using the head impulse paradigm to assess the vestibular-ocular reflex (VOR) gain of the six SCC in all three planes.Results: The study showed a significantly reduced VOR gain in lateral SCC among individuals with noise exposure in comparison to their healthy counterparts. In addition, refixation saccades (overt and covert) were noticed in 46 percent of individuals with noise exposure, whereas none of the participants exhibited refixation saccades in the control group.Conclusions: Although the semicircular canal is reported to be less susceptible to the effects of noise, the findings of reduced VOR gain and the presence of refixation saccades in the clinical group reveal that the semicircular functioning could be altered in individuals exposed to noise. Therefore, individuals with noise-induced hearing loss should undergo peripheral vestibular assessment, including semicircular canal functioning, for better rehabilitation. vHIT showed promising findings in assessing SCC functioning among individuals with noise exposure.