Brainstem-evoked responses of guinea pigs exposed to high noise levelsin utero

Abstract
Pregnant guinea pigs were exposed to loom room noise at 115 dB A for 7.5 hr/day for various periods during the last one‐third of pregnancy. When the hearing of their offspring was tested by auditory brain stem‐evoked response techniques at 6‐dB intervals, peak IV latencies of exposed pups were found to be significantly longer than those of otherwise similar control pups. The latency differences corresponded to a 5‐dB increase in stimulus at medium stimulus levels and 10–12 dB near threshold. The results indicate that it is possible for noise‐induced hearing loss to occur in utero in mammals whose auditory maturation process is complete, or nearly so, before birth.