Presbycusis

Presbycusis
Classification and external resources
Specialty otolaryngology
ICD-10 H91.1
OMIM 612448
DiseasesDB 11950
MedlinePlus 001045
eMedicine ent/224
Patient UK Presbycusis

Presbycusis (also spelled presbyacusis, from Greek presbys “elder” + akousis “hearing”[1]), or age-related hearing loss, is the cumulative effect of aging on hearing. It is a progressive and irreversible bilateral symmetrical age-related sensorineural hearing loss resulting from degeneration of the cochlea or associated structures of the inner ear or auditory nerves. The hearing loss is most marked at higher frequencies. Hearing loss that accumulates with age but is caused by factors other than normal aging (nosocusis and sociocusis) is not presbycusis, although differentiating the individual effects of multiple causes of hearing loss can be difficult.

Presbycusis is the most common cause of hearing loss, afflicting one out of three persons by age 65, and one out of two by age 75. Presbycusis is the second most common illness next to arthritis in aged people.

Presentation

Primary symptoms:

Secondary symptoms:

Usually occurs after age 50, but deterioration in hearing has been found to start very early, from about the age of 18 years. The ISO standard 7029 shows expected threshold changes due purely to age for carefully screened populations (i.e. excluding those with ear disease, noise exposure etc.), based on a meta-analysis of published data.[2][3] Age affects high frequencies more than low, and men more than women. One early consequence is that even young adults may lose the ability to hear very high frequency tones above 15 or 16 kHz. Despite this, age-related hearing loss may only become noticeable later in life. The effects of age can be exacerbated by exposure to environmental noise, whether at work or in leisure time (shooting, music, etc.). This is noise-induced hearing loss (NIHL) and is distinct from presbycusis. A second exacerbating factor is exposure to ototoxic drugs and chemicals

Over time, the detection of high-pitched sounds becomes more difficult, and speech perception is affected, particularly of sibilants and fricatives. Both ears tend to be affected. The impact of presbycusis on communication depends on both the severity of the condition and the communication partner.[4]

Diagnosis

Hearing loss is classified as mild, moderate, severe or profound. The Pure Tone Audiometry for air conduction thresholds at 500, 1000 and 2000Hz is traditionally used to classify the degree of hearing loss in each ear. Normal hearing thresholds are considered to be 25db sensitivity, though it has been proposed that this threshold is too high, and that 15db (about half as loud) is more typical. Mild hearing loss is thresholds of 25db-45db; moderate hearing loss is thresholds of 45db-65db; severe hearing loss is thresholds of 65-85db; and profound hearing loss thresholds are greater than 85db.

Tinnitus occurring in only one ear should prompt the clinician to initiate further evaluation for other etiologies. In addition, the presence of a pulse-synchronous rushing sound may require additional imaging to exclude vascular disorders.

Otoscopy

Main article: Otoscopy

An examination of the external ear canal and tympanic membrane performed by a medical doctor, otolaryngologist, or audiologist using an otoscope, a visual instrument inserted into the ear. This also allows some inspection of the middle ear through the translucent tympanic membrane.

Tympanometry

Main article: Tympanometry

A test administered by a medical doctor, otolaryngologist or audiologist of the tympanic membrane and middle ear function using a tympanometer, an air-pressure/sound wave instrument inserted into the ear canal. The result is a tympanogram showing...

Laboratory studies

This may include a blood or other sera test for inflammatory markers such as those for autoinflammatory diseases.

Audiometry

Main article: Audiometry

A hearing test administered by a medical doctor, otolaryngologist (ENT) or audiologist including pure tone audiometry and speech recognition may be used to determine the extent and nature of hearing loss, and distinguish presbycusis from other kinds of hearing loss. Otoacoustic emissions and evoked response testing may be used to test for audio neuropathy. The diagnosis of a sensorineural pattern hearing loss is made through audiometry, which shows a significant hearing loss without the "air-bone gap" that is characteristic of conductive hearing disturbances. In other words, air conduction is equal to bone conduction. Persons with cochlear deficits fail OtoAcoustic Emissions testing, while persons with 8th nerve deficits fail Auditory Brainstem Response testing

Magnetic Resonance Imaging (MRI)

Pathophysiology

Examples of microscopic changes seen in this condition are hair cell degeneration of the cochlea and giant stereociliary degeneration.

There are four pathological phenotypes of presbycusis:

In addition there are two other types:

The shape of the audiogram categorizes abrupt high-frequency loss (sensory phenotype) or flat loss (strial phenotype).

The mainstay of SNHL is strial, with only about 5% of cases being sensory. This type of presbycusis is manifested by a low-frequency hearing loss, with unimpaired speech recognition.

Classically, audiograms in neural presbycusis show a moderate downward slope into higher frequencies with a gradual worsening over time. A severe loss in speech discrimination is often described, out of proportion to the threshold loss, making amplification difficult due to poor comprehension.

The audiogram associated with sensory presbycusis is thought to show a sharply sloping high-frequency loss extending beyond the speech frequency range, and clinical evaluation reveals a slow, symmetric, and bilateral progression of hearing loss.

Causes

The aging process has three distinct components: physiologic degeneration, extrinsic damage (nosocusis), and intrinsic damage(sociocusis). These factors are superimposed on a genetic substrate, and may be overshadowed by general age-related susceptibility to diseases and disorders.

Hearing loss is only weakly correlated with age. In preindustrial and non-industrial societies, persons retain their hearing into old age. In the Framingham Cohort Study, only 10% of the variability of hearing with age could be explained by age-related physiologic deterioration. Within family groups, heredity factors were dominant; across family groups, other, presumably sociocusis and nosocusis factors were dominant.

Sociocusis

Nosocusis

Nosocusis factors that can cause hearing loss, which can be difficult to distinguish or separate from presbycusis, include:[5]

However, a recent study found that diabetes, atherosclerosis and hypertension had no correlation to presbycusis, suggesting that these are nosocusis (acquired hearing loss) factors, not intrinsic factors.

Treatment

At present, presbycusis, being primarily sensorineural in nature, cannot be prevented, ameliorated or cured. Treatment options fall into three categories: pharmacological, surgical and management.

There are no approved or recommended pharmaceutical treatments for presbycusis.

Cochlear implant

In cases of severe or profound hearing loss, a surgical cochlear implant is possible. This is an electronic device that replaces the cochlea of the inner ear. It provides a different kind of sound spectrum than natural hearing, but may enable the recipient to recognize speech and environmental sounds.

Management

Research

Pharmaceuticals

Pharmacological treatment options are limited, and remain clinically unproven. Among these are the water-soluble coenzyme Q10 formulation, the prescription drug Tanakan, and combination antioxidant therapy.

Stem cell Therapy

Popular culture

See also: The Mosquito

Recently, abilities of young people to hear high frequency tones that are inaudible to others over 25 or so has led to the development of technologies to disperse groups of young people around nearby British shops (The Mosquito), and the development of a cell phone ringtone, Teen Buzz, for students to use in school, that many older instructors are unable to hear. In September 2006 this technique was used to make a dance track called 'Buzzin'.[9] The track had two melodies, one that everyone could hear and one that only younger people could hear.

See also

External links

References

  1. Online Etymology Dictionary, Presbycousis
  2. D.W. Robinson and G.J. Sutton "Age effect in hearing -- a comparative analysis of published threshold data." Audiology 1979; 18(4): YOLO 320-334
  3. E. Van Eyken, G. Van Camp, L. Van Laer, "The Complexity of Age-Related Hearing Impairment: Contributing Environmental and Genetic Factors", Audiol Neurotol 2007;12:345-358
  4. 1 2 Huang, Qi; Tang, Jianguo (13 May 2010). "Age-related hearing loss or presbycusis". European Archives of Otorhinolaryngology 267 (8): 1179–1191. doi:10.1007/s00405-010-1270-7.
  5. "Age-Related Hearing Loss". National Institute on Deafness and Other Communication Disorders. NIH. Retrieved 17 November 2014.
  6. A. Salami, R. Mora, M. Dellepiane, G. Manini, V. Santomauro, L. Barettini, and L. Guastini (2010). "Water-soluble Coenzyme Q10 Formulation (Q-TER(®)) in the Treatment of Presbycusis". U.S. National Library of Medicine 130 (10): 1154–62. doi:10.3109/00016481003727590. PMID 20443731.
  7. 1 2 Mlu Boboshko, MV Efimova, and IV Savenko (2011). "Modern Aspects of Diagnosis of Presbycusis and Its Treatment in Elderly Patients". U.S. National Library of Medicine (2): 23–5. PMID 21512480.
  8. H Iwai and M. Inaba (2012). "Fetal Thymus Graft Prevents Age-related Hearing Loss and up Regulation of the IL-1 Receptor Type II Gene in CD4(+) T Cells". U.S. National Library of Medicine 250 (1-2): 1–8. doi:10.1016/j.jneuroim.2012.05.007. PMID 22652460.
  9. "UK | Wales | South East Wales | Secret alarm becomes dance track". BBC News. 2006-09-26. Retrieved 2013-08-01.
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