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Year: 2002  Vol. 6   Num. 3  - July/Sept Print:
Original Article
Texto Text in Portuguese
The Influence of Aging and of the Auditory Level on the Distortion Product Otoacoustic Emissions
A Influncia do Envelhecimento e do Grau de Audibilidade na Amplitude das Emisses Otoacsticas Produto de Distoro
Cintia T. Brito*, Doris Ruthi Lewis**.
Key words:
distortion product, cochlear physiology, aging

Introduction: It seems obvious to hypothesize that the distortion product otoacoustic emissions (DPOAE) might be affected by advanced age, as all other systems in the body. Objective: The aim of this study was to investigate the influence of aging and age-related hearing loss on DPOAEs amplitude. Methods: A total of 65 normal hearing and hearing impaired subjects (112 ears) aged from 50 to 82 years were evaluated. The cubic distortion product (2F1-F2) extending from 1.000 to 6.000Hz were measured in 1/ 3 octaves steps at stimulus level of 65/55 dB SPL and the F2/F1 ratio set at 1,22. A minimal amplitude of 3 dB SPL above the noise floor was the limit for a DPOAE to be considered present. Results: The DPOAE average and median amplitude were more robust in normal hearing ears. As the primary frequencies increased, the amplitude DPOAE became reduced in all subjects. Greater occurrence of absent amplitude responses and normal hearing were noted in subjects over sixties and present amplitude response and hearing threshold under 25 dB SPL in those from 50 to 59 years. According to frequency bands assessment, some similar DPOAE amplitude in subjects with or without hearing loss were observed in both groups of different ages. Conclusion: Auditory threshold <20dB HL showed more robust amplitudes, however an amplitude reduction was seen as F2 increased. Some amplitudes were not efficient to distinguish ears with or without sensorineural hearing loss.



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