Magnitude changes in transient evoked otoacoustic emissions and high-level 2f1-f2 distortion products in man during quinine administration.
Quinine reversibly affects the outer hair cells (OHC). It is therefore an ideal drug for studying OHC-related phenomena, such as transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs). Pure-tone thresholds (PTTs), 1,000-4,000 Hz, TEOAEs, and DPOAEs were measured monaurally in 5 normal-hearing volunteers during quinine administration. DPOAE was evoked at 75 dB SPL (f2/f1 = 1.22) and analysed at 2f1-f2 with f2 at 6 frequencies (700-4,000 Hz), while TEOAE was obtained at 79 dB SPLp and analysed at the f2 frequencies (1/3 octave). The PTT-shift was flat, 10 dB, whereas the TEOAE-power and the global mean of the DPOAEs decreased 4.5 dB and 1.4 dB, respectively. No correlation was found between the intra-individual emission shifts. It is concluded that TEOAE is more sensitive than high-level DPOAE for identifying minor cochlear hearing losses. Support is given to the hypothesis that different sources are involved in generating DPOAEs at different evoking levels.
Berninger
E
E
Department of Audiology, Karolinska Institute, Huddinge University Hospital, Sweden.
Karlsson
K K
KK
Hellgren
U
U
Eskilsson
G
G
D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D007758:Ear, Inner / Q000187:drug effects; D005260:Female; D006198:Hair Cells, Auditory / Q000187:drug effects*; D006311:Hearing Disorders / Q000139:chemically induced / Q000175:diagnosis; D006801:Humans; D011803:Quinine / Q000494:pharmacology*; D013018:Sound Spectrography
D011803:Quinine