Bert Maat
Pim van Dijk
Hero P. Wit
Inst. of Audiol., ENT Dept. Univ. Hospital Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
Spontaneous otoacoustic emission (SOAE) and click-evoked otoacoustic emission (CEOAE) measurements were performed in frogs (Rana esculenta). The SOAE and CEOAE measurements followed each other repeatedly, while the frog's body temperature was changed at a rate of approximately 0.1 (degrees)C/min. In some sessions, only SOAE measurements were performed. The SOAE and CEOAE spectra were closely related: The spectra of CEOAE contained the same peaks as those observed in the related SOAE spectrum. It seems that click evoked emissions in the frog are synchronized spontaneous emissions. The click-evoked responses show a nonlinear compressive amplitude growth with the stimulus intensity. As function of temperature, various emission modes, and complex amplitude patterns were observed for both types of emissions.