Description

• Age-related hearing loss (HL); it often presents as difficulty communicating in noisy conditions.
• Represents a lifetime of insults to the auditory system from toxic noise exposure and natural decline resulting in gradual, progressive, bilateral HL
• Usually presents as high-frequency HL with tinnitus (ringing)
• Impacts the “clarity” of sounds (i.e., ability to detect, identify, and localize sounds) making it difficult to hear in noisy conditions and reduced ability to understand speech.
• Central and peripheral causes:
  • Central presbycusis: age-related change in the auditory portions of the central nervous system, negatively impacting auditory perception, speech-communication performance, or both
  • Peripheral presbycusis: age-related, bilateral sensorineural HL (SNHL) typically symmetric
• No cure for presbycusis exists to date; management consists of mitigating risk factors and auditory amplification.
• Hearing aids (HAs) are the mainstay of treatment and are now sold over the counter for mild-to-moderate HL.
• Can lead to adverse effects on physical, cognitive, emotional, behavioral, and social function in the elderly (e.g., depression, social isolation) and is a contributor to all-cause dementia (1)

Epidemiology

Prevalence

• Increases with age—age 60 to 69 years: 27%; age 70 to 79 years: 55%; age >80 years: 81%
• Predominant sex: male > female

Etiology and Pathophysiology

• The external ear transmits sound energy to the tympanic membrane. The middle ear ossicles amplify and conduct the sound waves into the inner ear (cochlea) via the oval window. The organ of Corti, located in the cochlea, contains hair cells that detect these vibrations and depolarize, producing electrical signals that travel through the auditory nerve to the brain. These hair cells are susceptible to damage from a variety of insults and cannot be regenerated leading to cell death and permanent HL.
• Presbycusis is caused by the accumulated effects of noise exposure, systemic disease, oxidative damage, ototoxic drugs, and genetic susceptibility.

Genetics
Presbycusis has a clear familial aggregation:

• Genetic polymorphisms in genes encoding detoxification enzymes have been linked to age-related HL including GSTM1, GSTT1, and NAT2*6A (2).
• Other genes linked to age-related HL include GRM7, GRHL2, DFNA5, MYO6, and KCNQ4 (2)
• Mitochondrial DNA mutations/deletions have also been implicated in age-related HL (3).

Risk Factors

• Advancing age
• Noise exposure (military, industrial, leisure etc.)
• Ototoxic substances (organic solvents, heavy metals, carbon monoxide)
• Drugs (aminoglycosides, cisplatin [dose dependent], salicylates, NSAIDs, diuretics, antimalarials)
• Cigarette smoking
• Alcohol abuse
• Lower socioeconomic status
• Family history of presbycusis
• Head trauma (temporal bone fractures)
• Cardiovascular disease (hypertension, atherosclerosis, hyperlipidemia)
• Diabetes mellitus
• Autoimmune disease (auto cochleitis/labyrinthitis)
• Metabolic bone disease
• Endocrine medical conditions: levels of aldosterone
• Otologic conditions (e.g., Ménière disease or otosclerosis)

General Prevention

• Avoid hazardous noise exposure.
• Use hearing protection (earmuffs, earplugs).
• Screening
  • Based on a 2021 review, according to the USPSTF, there is an insufficient evidence to assess the relative benefits and harms of HL screening in adults aged ≥50 years.
  • Hearing Handicap Inventory for the Elderly Screening (4)
  • RCT published in 2010 on screening for HL, HA use was significantly higher in three screened groups (4.1% in those using a questionnaire, 6.3% using handheld audiometry, and 7.4% using both modalities) versus unscreened control participants (3.3%) at 1-year follow-up (5)[B].

Commonly Associated Conditions

• Accelerated multidomain cognitive decline, cognitive impairment, and dementia (6)[A]
• A variety of cognitive, behavioral, and psychosocial disorders (7)