Effect of Aging on Otoacoustic Emission in Elderly with Normal Hearing

Background: Otoacoustic emissions (OAEs), sounds generated by the cochlea and detected in the external ear canal, are four types: transient evoked (TEOAEs), distortion product (DPOAEs), spontaneous, and stimulus frequency OAEs. TEOAEs and DPOAEs are commonly used to assess cochlear function. While the exact mechanisms of OAE generation are not fully understood, they likely involve the contractility of outer hair cells. OAEs can indicate cochlear health, with TEOAEs responsive to hearing thresholds up to 30 dB HL. Age-related hearing loss is caused by permanent inner ear damage that converts sound into electrical impulses. Many ageing ears showed significant strial degeneration throughout the cochlea, but no longer affects pure-tone thresholds. These results are the first quantitative assessment of hair cell mortality in normal-aging human cochleas and show loss in low-frequency areas and more severe loss in high-frequency regions. Objectives: to Preserve normal hearing as far as possible, To determine risk factors leading to hearing impairment, and to Early diagnosis for early intervention and good prognosis. Patients and methods: This cross-sectional study was carried out on 30 patients aged ≥ 60 years old, both sexes, with normal hearing. Basic audiological evaluation was done including tympanometry, Pure tone and speech audiometry as well as otoacoustic emission. Results: There was a significant change in auditory thresholds between the first and second evaluations at 4,5kHz in both ears. The average age of males was significantly higher in males than females. In the left ear examination, external auditory canal, tympanometry was a significant higher in females than males. In the left and right ear, the tympanic membrane and the cone of light were intact and preserved in all subjects. In the right ear, mission failure at 5000Hz, it was a significant higher in males than female (P<0.05). In the left ear, emission failure at 4000 and 5000 Hz was a significant higher in males than female (P<0.05). Regression analysis indicated a significant association between age and failed emissions at 4, 5kHz suggesting age-related cochlear damage. Conclusions: OAE is a reliable test for detection of age-related cochlear damage. The results indicate significant changes in auditory thresholds, particularly at high frequencies, suggesting age-related alterations in cochlear function.