title: Use of DPOAEs for assessing hearing loss caused by styrene in the rat.
abstract: The study was carried out to test whether or not cubic distortion otoacoustic emissions were more sensitive than auditory-evoked potentials for assessing styrene-induced hearing losses in the Long-Evans rat. For the purposes of comparison, changes in cubic distortion product otoacoustic emissions (DeltaDPOAE), evoked potential permanent threshold shifts (PTS) and outer hair cell losses were measured in a population of styrene-treated rats. Each rat was exposed to either 650 or 750 ppm of styrene for 4 weeks, 5 days per week, 6 h per day. Only the 750 ppm exposure caused significant hearing losses. For this concentration, DPOAEs appeared as sensitive to styrene as the audiometry performed with evoked potentials, but not more. A high coefficient of correlation [0.84< or =r< or =0.91] between DeltaDPOAE and PTS was obtained across the styrene-induced effects for frequencies ranging from 5 to 12 kHz. This experiment demonstrates that DPOAEs can be used to monitor the ototoxicity induced by styrene even though they cannot be considered as a more sensitive index of cochlear pathology than the evoked potentials, at least under our experimental conditions. Likewise evoked potentials, normal DPOAEs may not guarantee a normal cochlear status and therefore results of DPOAE measurements should be interpreted cautiously. The use of both techniques and the determination of the ratio DeltaDPOAE/PTS may be useful in determining the cause of hearing loss: mechanical or chemical process. Moreover, because of its non-invasive and objective characteristics, the use of DPOAEs could play a greater role in a prevention policy.
authors.affiliation: Laboratoire de Neurotoxicité, Institut National de Recherche et de Sécurité, Avenue de Bourgogne, P.O. Box 27, 54501 Vandoeuvre, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Pouyatos
authors.forename: Pierre
authors.initials: P
authors.lastname: Campo
authors.forename: Robert
authors.initials: R
authors.lastname: Lataye
mesh_terms: D000818:Animals; D001309:Auditory Threshold; D016923:Cell Death; D003638:Deafness / Q000139:chemically induced* / Q000175:diagnosis* / Q000473:pathology; D005072:Evoked Potentials, Auditory; D018072:Hair Cells, Auditory, Outer / Q000473:pathology / Q000502:physiology; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D010469:Perceptual Distortion / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D012680:Sensitivity and Specificity; D012997:Solvents; D020058:Styrene
chemical_list: D012997:Solvents; D020058:Styrene