EFFECT OF TEMPERATURE ELEVATION ON RABBIT COCHLEAR FUNCTION AS MEASURED BY DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS

Low-intensity laser stapedotomy has been shown to produce temperature elevations of 3 degrees to 4 degrees C within the cochlea, This study investigates the effect of temperature elevations in this range on coc hlear outer hair cell function by use of distortion-product otoacousti c emissions in rabbits, Using esophageal temperature monitoring, we co mpared 2f(1)-f(2) distortion-product otoacoustic emissions over a rang e of frequencies (1806 to 8691 Hz) at rabbit normothermia, normothermi a plus 3 degrees C, and normothermia after passive cooling, Cochlear t emperature was found to exceed changes in esophageal temperature by as much as 1.2 degrees C, We found that a maximum of 3 degrees C elevati on in esophageal temperature did not permanently impair outer hair cel l function in the rabbit cochlea, Results of this study suggest that m oderate changes in cochlear temperature, such as those produced by low -intensity CO2 and holmium-yttrium aluminum garnet lasers, may not pro duce irreversible thermal damage to the cochlear outer hair cells.