Comparison of distortion-product and transient evoked otoacoustic emissions with ABR threshold shift in chinchillas with ototoxic damage.
In this study we compare distortion product otoacoustic emissions (DPOAEs), transient evoked otoacoustic emissions (TEOAEs) and ABR threshold shifts in an animal model (chinchilla) of cochlear hearing loss. Subjects were treated with an aminoglycoside (amikacin) to produce basal cochlear lesions of various degree. DPOAE and TEOAE were measured throughout the treatment period and until hearing thresholds stabilized. ABR thresholds to tone pip stimuli were determined. Cytocochleograms of cochleas were prepared using scanning microscopy. DPOAEs (2f1-f2) were compared to fast Fourier transform (FFT)-analyzed TEOAEs components in the 1-, 2-, and 4-kHz frequency regions. Both types of emission were compared with corresponding ABR thresholds. There was no significant linear correlation between these different measures of cochlear function. Moreover, the amplitudes of DPOAEs reflected smaller regions of cochlear outer hair cell (OHC) damage better than TEOAEs. These results suggest that DPOAEs can be used to more accurately monitor hair cell function at specific hearing locations than TEOAEs.
Kakigi
A
A
Department of Otolaryngology, Hospital for Sick Children, University of Toronto, Canada.
Hirakawa
H
H
Harel
N
N
Mount
R J
RJ
Harrison
R V
RV
D000583:Amikacin / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D001300:Audiometry, Evoked Response; D001309:Auditory Threshold / Q000187:drug effects; D001933:Brain Stem / Q000187:drug effects; D002682:Chinchilla; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D005583:Fourier Analysis; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced* / Q000473:pathology; D008855:Microscopy, Electron, Scanning; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects*; D012815:Signal Processing, Computer-Assisted
D000900:Anti-Bacterial Agents; D000583:Amikacin