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- Presbycusis is an age-related hearing loss (HL), showing increased incidence with age. It often presents as difficulty communicating in noisy conditions.
- May be divided into 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
- Represents a lifetime of insults to the auditory system from toxic noise exposure and natural decline
- Initially presents as high-frequency SNHL with tinnitus (ringing)
- Impacts the “clarity” of sounds (i.e., ability to detect, identify, and localize sounds)
- Due to mild and progressive nature, presbycusis is often treated with amplification alone.
- Can lead to adverse effects on physical, cognitive, emotional, behavioral, and social function in the elderly (e.g., depression, social isolation)
According to an ongoing community-based epidemiologic study, the 10-year cumulative incidence rates of HL are as follows, approximately:
- Age 48 to 59 years: M (31.7%), F (15.6%); all (21.8%)
- Age 60 to 69 years: M (56.8%), F (40.7%); all (45.5%)
- Age 70 to 79 years: M (87.1%), F (70.6%); all (73.7%)
- Age 80 to 92 years: M (100%), F (100%); all (100%)
- 10% of the population develops SNHL severe enough to impair communication.
- Increases to 40% in the population >65 years of age
- 80% of HL cases occur in elderly patients.
- Only 10–20% of older adults with HL have ever used hearing aids (HAs).
- Predominant sex: male > female
- Hearing levels are poorer in industrialized societies than in isolated or agrarian societies.
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. Toxic noise exposure traumatizes the hair cells and leads to cell death and HL. New research also suggests that overexcitation of the neurosynapses causes increased glutamate, which is also neurotoxic (1).
- Sensory presbycusis: primary loss of the hair cells in the basal end of the cochlea (high-frequency HL)
- Neural presbycusis: loss of spiral ganglion cells (nerve cells induced by hair cells to produce action potentials to travel to the brainstem)
- Strial (metabolic) presbycusis: atrophy of the stria vascularis (the cochlear tissue that generates the endocochlear electrical potential)
- Cochlear conductive (mechanical) presbycusis: no morphologic findings (presumed stiffening of the basilar membrane)
- Mixed presbycusis: combinations of hair cell, ganglion cell, and stria vascularis loss
- Indeterminate presbycusis: no morphologic findings (presumed impaired cellular function)
- Presbycusis is caused by the accumulated effects of noise exposure, systemic disease, oxidative damage, ototoxic drugs, and genetic susceptibility.
Presbycusis has a clear familial aggregation:
- Heritability estimates show 35–55% of the variance of sensory presbycusis is from genetic factors; even greater percentage in strial presbycusis
- Heritability is stronger among women than men.
- Noise exposure (military, industrial, etc.)
- Ototoxic substances
- Organic solvents
- Heavy metals
- Carbon monoxide
- Tobacco smoking
- Lower socioeconomic status
- Family history of presbycusis
- Head trauma (temporal bone fractures)
- Cardiovascular disease (hypertension, atherosclerosis, hyperlipidemia); labyrinthine artery is terminal artery to the cochlea.
- Diabetes mellitus
- Autoimmune disease (autocochleitis/labyrinthitis)
- Metabolic bone disease
- Endocrine medical conditions: levels of aldosterone
- Alzheimer disease
- Otologic conditions (e.g., Ménière disease or otosclerosis)
- Avoid hazardous noise exposure.
- Use hearing protection.
- Maintain healthy diet and exercise.
- In the only published RCT 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 (2)[B].
- Based on a 2011 review, according to the USPSTF, there is insufficient evidence to assess the relative benefits and harms of HL screening in adults ≥50 years (3)[A].