title: [Otoacoustic distortion products in adults with normal hearing].
abstract: Distortion Product Otoacoustic Emissions (DPOEs) are otoacoustic emissions evoked by two pure equilevel tones (f1, f2) called primaries and are believed to provide frequency-specific information regarding cochlear function. We recorded DPOEs at 2f1-f2 frequency with a constant frequency ration (f2/f1 = 1.22) in 8 normal hearing subjects (16 ears, mean age 28 +/- 1.5) to establish the characteristics of these emissions in the adult population. DPOEs were measured at the following F2 frequencies and respective fp geometric mean frequencies: 696/632, 1001/904, 1501/1360, 2002/1809, 3003/2714, 4004/3626, 5005/4531 e 6006/5435 Hz. Detailed testing included the recording of DPOE "audiograms" and input-output functions depicting the relationship of the amplitudes of DPOE to primary-tone levels ranging from 25 to 70 dB SPL in 5 dB steps. The present findings are in good agreement with investigations based on evoked otoacoustic emissions published by other researchers. The average DPOE "audiograms" demonstrated a low-frequency maximum at 1501 Hz (f2)/1360 (fp) and a high-frequency peak at 5005 Hz (f2)/4531 (fp). The two maximum regions were separated by a minimum around 3003 Hz (f2)/2714 (fp). This study confirms the feasibility of DPOE measurements among adults and provide a normal baseline for this age group. DPOEs could be useful, in association with evoked otoacoustic emissions and with auditory brainstem responses, in obtaining a precise evaluation of the peripheral auditory system.
authors.affiliation: Istituto di Clinical Otorinolaringoiatrica e Chirurgia Cervicofacciale, Università di Perugia.
authors.forename: C
authors.initials: C
authors.lastname: Simoncelli
authors.forename: E
authors.initials: E
authors.lastname: Molini
authors.forename: G
authors.initials: G
authors.lastname: Ricci
authors.forename: B
authors.initials: B
authors.lastname: Capolunghi
authors.forename: N
authors.initials: N
authors.lastname: Alunni
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D003051:Cochlea / Q000502:physiology*; D004558:Electric Stimulation; D016057:Evoked Potentials, Auditory, Brain Stem; D006309:Hearing / Q000502:physiology*; D006801:Humans