TRANSIENT EVOKED OTOACOUSTIC EMISSIONS CAN BE RECORDED IN THE RAT

Transient (click) evoked (TEOAE) and distortion product (DPOAE) otoaco ustic emissions can be recorded in most normal human ears. Even though DPOAEs have been recorded in many laboratory animals, there has not b een much success in recording TEOAEs in non-primate mammals except for guinea pigs. In this study, TEOAEs were unequivocally recorded in eve ry rat (and guinea pig) ear studied by using short pulses (40 mu s) to generate the clicks and a short (1.1 ms) amplifier gain suppression p eriod. The responses were reproducible in the same rat, above the nois e floor and disappeared post-mortem They were shorter in duration in r ats than in guinea pigs and were made up of a broadband frequency spec trum between 2 and 4 kHz. Post-mortem, the TEOAEs to 65 dB SPL clicks disappeared at about the same time as DPOAEs to low stimulus intensiti es and before the DPOAEs to high stimulus intensities. The ability to record TEOAEs in rats and other animals should permit further experime ntation into the basic mechanisms of generation of otoacoustic emissio ns in general and TEOAEs in particular.