What is Age-Related Hearing Loss
Age-related hearing loss refers to the hearing impairment that occurs as a result of the aging process. The American Association of Audiology, Bioacoustics, and Biomechanics defines age-related hearing loss as a combination of factors, including noise exposure, the use of ototoxic drugs, internal medical conditions, and medical interventions. This encompasses various factors, including physiological degeneration, contributing to hearing loss in the elderly. The causes may be related to age, metabolic issues, vascular problems, kidney disease, medications, and noise exposure.
Due to the complexity of the pathogenic factors of age-related hearing loss, pathological changes can affect the entire auditory system, including the outer ear, middle ear, inner ear, cochlear nerve, central conduction pathways, and cortex. Histological changes primarily manifest as cochlear damage, involving degeneration of hair cells, vascular patterns, supporting structures, and spiral ganglion cells.
Characteristics of Age-Related Hearing Loss
The characteristics of age-related hearing loss are distinct from other types of hearing impairments and can be summarized as follows:
- Pure-tone bilateral hearing loss exhibits symmetric decline with no air-bone gap.
- High-frequency loss dominates the pure-tone audiogram, with sloping and steep-sloping curves being common, followed by flat curves. Other shapes are rare. Patients often exhibit reduced sensitivity to high-frequency sounds such as bird songs, phone rings, doorbells, and watch alarms.
- The progression of hearing loss is gradual, and hearing thresholds increase with age.
- Speech discrimination loss is generally more noticeable than pure-tone hearing loss.
- Half of the subjects may exhibit positive results in supra-threshold tests.
- Poor ability in sound localization and direction.
- Auditory Brainstem Response (ABR) wave latencies increase with age, with symmetric wave latency differences and no close correlation between wave differentiation and pure-tone thresholds.
- Most individuals experience varying degrees of tinnitus.