EFFECTS OF ACUTE STYRENE AND SIMULTANEOUS NOISE EXPOSURE ON AUDITORY FUNCTION IN THE GUINEA-PIG

Although styrene has been demonstrated to disrupt vestibular function acutely, parallel studies have not been conducted in the auditory syst em. This article presents data on the effects of acute styrene adminis tration by injection and inhalation on cochlear function. No deleterio us effect of the maximally tolerated styrene dose on hearing was ident ified when cochlear function was assessed using a within-subjects desi gn. When guinea pigs were administered styrene by inhalation during a single 7-h period, normal auditory function was observed both 1 and 7 days later as compared to chamber controls which did not receive styre ne. In some instances, the interactive effects of noise and simultaneo us styrene inhalation were studied to determine whether chemical expos ure might enhance the disruptive effects of noise on hearing. While a persistent noise-induced hearing loss was observed 1 day following exp osure, subjects administered styrene simultaneously did not show a gre ater hearing loss than those receiving noise alone. Finally, when a 7- day recovery period for noise-induced hearing loss was interposed befo re audiometric testing, the combined exposure to styrene and noise was not more potent than noise alone in elevating auditory thresholds. Al though auditory dysfunction has been reported following subchronic sty rene administration, the current results do not support an ototoxic ef fect of styrene at the level of the cochlea with short-term exposure.