Editing Hearing loss (section)

==Causes==
{{Main|Causes of hearing loss}}
Hearing loss has multiple causes, including ageing, genetics, perinatal problems and acquired causes like noise and disease.  For some kinds of hearing loss the cause may be classified as [[idiopathic|of unknown cause]].{{cn|date=December 2024}}

There is a progressive loss of ability to hear high frequencies with aging known as [[presbycusis]]. For men, this can start as early as 25 and women at 30. Although genetically variable, it is a normal concomitant of ageing and is distinct from hearing losses caused by noise exposure, toxins or disease agents.<ref>{{cite journal | vauthors = Robinson DW, Sutton GJ | title = Age effect in hearing – a comparative analysis of published threshold data | journal = Audiology | volume = 18 | issue = 4 | pages = 320–334 | year = 1979 | pmid = 475664 | doi = 10.3109/00206097909072634 }}</ref> Common conditions that can increase the risk of hearing loss in elderly people are [[high blood pressure]], [[diabetes]] ([[hearing loss in diabetes]]),<ref>{{Cite journal |last1=Abraham |first1=Abin M |last2=Jacob |first2=Jubbin Jagan |last3=Varghese |first3=Ashish |date=2023-09-28 |title=Should We Screen Patients with Type 2 Diabetes Mellitus for Hearing Loss? |url=https://www.agingmedhealthc.com/?p=25146 |journal=Aging Medicine and Healthcare |volume=14 |issue=3 |pages=102–113 |doi=10.33879/AMH.143.2022.01008|doi-access=free }}</ref> or the use of certain medications harmful to the ear.<ref>{{cite book | vauthors = Worrall L, Hickson LM | date = 2003 | chapter = Communication activity limitations | pages = 141–142 | veditors = Worrall LE, Hickson LM | title = Communication disability in aging: from prevention to intervention | location = Clifton Park, NY | publisher = Delmar Learning }}</ref><ref>{{cite journal | vauthors = Akinpelu OV, Mujica-Mota M, Daniel SJ | title = Is type 2 diabetes mellitus associated with alterations in hearing? A systematic review and meta-analysis | journal = The Laryngoscope | volume = 124 | issue = 3 | pages = 767–776 | date = March 2014 | pmid = 23945844 | doi = 10.1002/lary.24354 | s2cid = 25569962 }}</ref> While everyone loses hearing with age, the amount and type of hearing loss is variable.<ref>{{cite web|title=Hearing Loss and Older Adults|url=https://www.nidcd.nih.gov/health/hearing-loss-older-adults|publisher=National Institute on Deafness and Other Communication Disorders|access-date=September 11, 2016|format=Last Updated June 3, 2016|url-status=live|archive-url=https://web.archive.org/web/20161004200407/https://www.nidcd.nih.gov/health/hearing-loss-older-adults|archive-date=October 4, 2016|date=2016-01-26}}</ref>

[[Noise-induced hearing loss]] (NIHL), also known as [[acoustic trauma]], typically manifests as elevated hearing thresholds (i.e. less sensitivity or muting). Noise exposure is the cause of approximately half of all cases of hearing loss, causing some degree of problems in 5% of the population globally.<ref name=Oishi2011>{{cite journal | vauthors = Oishi N, Schacht J | title = Emerging treatments for noise-induced hearing loss | journal = Expert Opinion on Emerging Drugs | volume = 16 | issue = 2 | pages = 235–245 | date = June 2011 | pmid = 21247358 | pmc = 3102156 | doi = 10.1517/14728214.2011.552427 }}</ref> The majority of hearing loss is not due to age, but due to noise exposure.<ref>{{cite web| url=http://blogs.cdc.gov/niosh-science-blog/2015/03/25/hl-impact-story/| title=CDC – NIOSH Science Blog – A Story of Impact....| work=cdc.gov| date=25 March 2015| url-status=live| archive-url=https://web.archive.org/web/20150613044654/http://blogs.cdc.gov/niosh-science-blog/2015/03/25/hl-impact-story/| archive-date=2015-06-13}}</ref> Various governmental, industry and standards organizations set noise standards.<ref>In the United States, [[United States Environmental Protection Agency]], [[Occupational Safety and Health Administration]], [[National Institute for Occupational Safety and Health]], [[Mine Safety and Health Administration]], and numerous state government agencies among others, set noise standards.</ref> Many people are unaware of the presence of environmental sound at damaging levels, or of the level at which sound becomes harmful. Common sources of damaging noise levels include car stereos, children's toys, motor vehicles, crowds, lawn and maintenance equipment, power tools, gun use, musical instruments, and even hair dryers. Noise damage is cumulative; all sources of damage must be considered to assess risk. In the US, 12.5% of children aged 6–19 years have permanent hearing damage from excessive noise exposure.<ref name="kid">{{cite web| url=https://www.cdc.gov/healthyyouth/noise/| title=Noise-Induced Hearing Loss: Promoting Hearing Health Among Youth| work=CDC Healthy Youth!| publisher=CDC| date=2009-07-01| url-status=live| archive-url=https://web.archive.org/web/20091221020243/http://www.cdc.gov/healthyyouth/noise/| archive-date=2009-12-21}}</ref>  The World Health Organization estimates that half of those between 12 and 35 are at risk from using [[personal audio devices]] that are too loud.<ref name="WHO2015Aud" /> Hearing loss in adolescents may be caused by loud noise from toys, music by headphones, and concerts or events.<ref>{{cite journal | vauthors = de Laat JA, van Deelen L, Wiefferink K | title = Hearing Screening and Prevention of Hearing Loss in Adolescents | journal = The Journal of Adolescent Health | volume = 59 | issue = 3 | pages = 243–245 | date = September 2016 | pmid = 27562364 | doi = 10.1016/j.jadohealth.2016.06.017 | doi-access = free }}</ref><ref>[https://www.cdc.gov/vitalsigns/hearingloss/index.html Too Loud! For Too Long! Loud noises damage hearing] ''U.S. Department of Health and Human Services, Centers for Disease Control and Prevention'', [[National Center for Environmental Health]]. (6 January 2020).</ref>

Hearing loss can be inherited. Around 75–80% of all these cases are inherited by [[recessive genes]], 20–25% are inherited by [[dominant genes]], 1–2% are inherited by [[X-linked]] patterns, and fewer than 1% are inherited by [[mitochondrial inheritance]].<ref name="Harvard">{{cite web| last=Rehm| first=Heidi | title=The Genetics of Deafness; A Guide for Patients and Families| url=http://hearing.harvard.edu/info/GeneticDeafnessBookletV2.pdf| work=Harvard Medical School Center For Hereditary Deafness| publisher=Harvard Medical School| url-status=dead| archive-url=https://web.archive.org/web/20131019153702/http://hearing.harvard.edu/info/GeneticDeafnessBookletV2.pdf| archive-date=2013-10-19}}</ref>  Syndromic deafness occurs when there are other signs or medical problems aside from deafness in an individual,<ref name="Harvard" /> such as [[Usher syndrome]], [[Stickler syndrome]], [[Waardenburg syndrome]], [[Alport's syndrome]], and [[neurofibromatosis type 2]]. [[Nonsyndromic deafness]] occurs when there are no other signs or medical problems associated with the deafness in an individual.<ref name="Harvard" />

[[Fetal alcohol spectrum disorder]]s are reported to cause hearing loss in up to 64% of infants born to [[alcoholism|alcoholic]] mothers, from the ototoxic effect on the developing fetus plus malnutrition during pregnancy from the excess [[ethanol|alcohol]] intake. [[Premature birth]] can be associated with sensorineural hearing loss because of an increased risk of [[hypoxia (medical)|hypoxia]], [[hyperbilirubinaemia]], ototoxic medication and infection as well as noise exposure in the neonatal units. Also, hearing loss in premature babies is often discovered far later than a similar hearing loss would be in a full-term baby because normally babies are given a hearing test within 48 hours of birth, but doctors must wait until the premature baby is medically stable before testing hearing, which can be months after birth.<ref>{{cite web |title=Hearing Loss in Premature Babies |url=https://www.salusuhealth.com/Pennsylvania-Ear-Institute/Events/News-Stories/Hearing-Loss-in-Premature-Babies.aspx |website=Salus Health |publisher=Pennsylvania Ear Institute |access-date=16 August 2020 |date=2016}}</ref> The risk of hearing loss is greatest for those weighing less than 1500&nbsp;g at birth.

Disorders responsible for hearing loss include [[auditory neuropathy]],<ref>{{cite journal | vauthors = Starr A, Sininger YS, Pratt H | title = The varieties of auditory neuropathy | journal = Journal of Basic and Clinical Physiology and Pharmacology | volume = 11 | issue = 3 | pages = 215–230 | date = 2011 | pmid = 11041385 | doi = 10.1515/JBCPP.2000.11.3.215 | s2cid = 31806057 }}</ref><ref>{{cite journal | vauthors = Starr A, Picton TW, Sininger Y, Hood LJ, Berlin CI | title = Auditory neuropathy | journal = Brain | volume = 119 ( Pt 3) | issue = 3 | pages = 741–753 | date = June 1996 | pmid = 8673487 | doi = 10.1093/brain/119.3.741 | doi-access = free }}</ref> [[Down syndrome]],<ref name="Rod2012">{{cite journal | vauthors = Rodman R, Pine HS | title = The otolaryngologist's approach to the patient with Down syndrome | journal = Otolaryngologic Clinics of North America | volume = 45 | issue = 3 | pages = 599–629, vii–viii | date = June 2012 | pmid = 22588039 | doi = 10.1016/j.otc.2012.03.010 }}</ref> [[Charcot–Marie–Tooth disease]] variant 1E,<ref>{{cite web|last1=McKusick|first1=Victor A.|last2=Kniffen|first2=Cassandra L. |title=# 118300 Charcot–Marie Tooth Disease and Deafness |url=http://omim.org/entry/118300|website=Online Mendelian Inheritance in Man|access-date=2 March 2018|date=30 January 2012}}</ref> [[autoimmune disease]], [[multiple sclerosis]], [[meningitis]], [[cholesteatoma]], [[otosclerosis]], [[perilymph fistula]], [[Ménière's disease]], recurring ear infections, strokes, [[superior semicircular canal dehiscence]], [[Pierre Robin syndrome|Pierre Robin]], [[Treacher Collins syndrome|Treacher-Collins]], [[Usher Syndrome]], [[Pendred syndrome|Pendred Syndrome]], and [[Turner syndrome|Turner]] syndrome, [[syphilis]], [[vestibular schwannoma]], and [[Virus|viral infections]] such as [[measles]], [[mumps]], congenital [[rubella]] (also called German measles) syndrome, several varieties of [[Herpesviridae|herpes virus]]es,<ref>{{cite journal | vauthors = Byl FM, Adour KK | title = Auditory symptoms associated with herpes zoster or idiopathic facial paralysis | journal = The Laryngoscope | volume = 87 | issue = 3 | pages = 372–379 | date = March 1977 | pmid = 557156 | doi = 10.1288/00005537-197703000-00010 | s2cid = 41226847 | doi-access = free }}</ref><ref name="Eggermont2017">{{cite book|author=Jos J. Eggermont|title=Hearing Loss: Causes, Prevention, and Treatment|url=https://books.google.com/books?id=fJExDQAAQBAJ&pg=PA198|date= 2017|publisher=Elsevier Science|isbn=978-0-12-809349-8|pages=198–}}</ref> [[HIV/AIDS]],<ref>{{cite journal | vauthors = Araújo E, Zucki F, Corteletti LC, Lopes AC, Feniman MR, Alvarenga K | title = Hearing loss and acquired immune deficiency syndrome: systematic review | journal = Jornal da Sociedade Brasileira de Fonoaudiologia | volume = 24 | issue = 2 | pages = 188–192 | date = 2012 | pmid = 22832689 | doi = 10.1590/s2179-64912012000200017 | doi-access = free }}</ref> and [[West Nile fever|West Nile virus]].

Some medications may reversibly or irreversibly affect hearing. These medications are considered [[Ototoxicity|ototoxic]]. This includes [[loop diuretic]]s such as furosemide and bumetanide, [[non-steroidal anti-inflammatory drug]]s (NSAIDs) both over-the-counter (aspirin, ibuprofen, naproxen) as well as prescription (celecoxib, diclofenac, etc.), paracetamol, [[quinine]], and [[macrolide antibiotics]].<ref name="Analgesic">{{cite journal | vauthors = Curhan SG, Shargorodsky J, Eavey R, Curhan GC | title = Analgesic use and the risk of hearing loss in women | journal = American Journal of Epidemiology | volume = 176 | issue = 6 | pages = 544–554 | date = September 2012 | pmid = 22933387 | pmc = 3530351 | doi = 10.1093/aje/kws146 }}</ref> Others may cause permanent hearing loss.<ref name="asha">{{cite web| url=http://www.asha.org/public/hearing/Ototoxic-Medications/| title=Ototoxic Medications (Medication Effects)| first1=Barbara| last1=Cone| first2=Patricia| last2=Dorn| first3=Dawn| last3=Konrad-Martin| first4=Jennifer| last4=Lister| first5=Candice| last5=Ortiz| first6=Kim| last6=Schairer | publisher=American Speech-Language-Hearing Association}}</ref> The most important group is the [[aminoglycoside]]s (main member [[gentamicin]]) and platinum based chemotherapeutics such as [[cisplatin]] and [[carboplatin]].<ref>{{cite journal | vauthors = Rybak LP, Mukherjea D, Jajoo S, Ramkumar V | title = Cisplatin ototoxicity and protection: clinical and experimental studies | journal = The Tohoku Journal of Experimental Medicine | volume = 219 | issue = 3 | pages = 177–186 | date = November 2009 | pmid = 19851045 | pmc = 2927105 | doi=10.1620/tjem.219.177}}</ref><ref>{{cite journal | vauthors = Rybak LP, Ramkumar V | title = Ototoxicity | journal = Kidney International | volume = 72 | issue = 8 | pages = 931–935 | date = October 2007 | pmid = 17653135 | doi = 10.1038/sj.ki.5002434 | doi-access = free }}</ref>

In addition to medications, hearing loss can also result from specific chemicals in the environment: metals, such as [[lead]]; [[solvents]], such as [[toluene]] (found in [[crude oil]], [[gasoline]]<ref name="tol-nih">{{cite web| url=http://toxtown.nlm.nih.gov/text_version/chemicals.php?id=30| title=Tox Town – Toluene – Toxic chemicals and environmental health risks where you live and work – Text Version| publisher=toxtown.nlm.nih.gov| access-date=2010-06-09| url-status=live| archive-url=https://web.archive.org/web/20100609052911/http://toxtown.nlm.nih.gov/text_version/chemicals.php?id=30| archive-date=2010-06-09}}</ref> and [[automobile exhaust]],<ref name="tol-nih" /> for example); and [[asphyxiant gas|asphyxiant]]s.<ref name="def9">{{cite news| title=Addressing the Risk for Hearing Loss from Industrial Chemicals| first=Thais C.| last=Morata| url=https://www.cdc.gov/niosh/topics/noise/pubs/presentations/AOHC.swf| publisher=CDC| access-date=2008-06-05| url-status=dead| archive-url=https://web.archive.org/web/20090122171205/http://www.cdc.gov/niosh/topics/noise/pubs/presentations/AOHC.swf| archive-date=2009-01-22}}</ref> Combined with noise, these ototoxic chemicals have an additive effect on a person's hearing loss.<ref name="def9" /> Hearing loss due to chemicals starts in the high frequency range and is irreversible. It damages the [[cochlea]] with lesions and degrades central portions of the [[auditory system]].<ref name="def9" /> For some ototoxic chemical exposures, particularly styrene,<ref name="tm">{{cite journal| last=Johnson| first=Ann-Christin| date=2008-09-09| title=Occupational exposure to chemicals and hearing impairment – the need for a noise notation| url=http://awww.arbetsmiljoverket.se/dokument/arkiv/neg/Chemicals_and_hearing_impairment.pdf| journal=Karolinska Institutet| pages=1–48| access-date=2009-06-19| archive-date=2012-09-06| url-status=dead| archive-url=https://web.archive.org/web/20120906103148/http://awww.arbetsmiljoverket.se/dokument/arkiv/neg/Chemicals_and_hearing_impairment.pdf}}</ref> the risk of hearing loss can be higher than being exposed to [[noise]] alone. The effects is greatest when the combined exposure include [[impulse noise (audio)|impulse noise]].<ref>{{cite journal | vauthors = Venet T, Campo P, Thomas A, Cour C, Rieger B, Cosnier F | title = The tonotopicity of styrene-induced hearing loss depends on the associated noise spectrum | journal = Neurotoxicology and Teratology | volume = 48 | pages = 56–63 | date = March 2015 | pmid = 25689156 | doi = 10.1016/j.ntt.2015.02.003 | bibcode = 2015NTxT...48...56V }}</ref><ref>{{cite journal | vauthors = Fuente A, Qiu W, Zhang M, Xie H, Kardous CA, Campo P, Morata TC | title = Use of the kurtosis statistic in an evaluation of the effects of noise and solvent exposures on the hearing thresholds of workers: An exploratory study | journal = The Journal of the Acoustical Society of America | volume = 143 | issue = 3 | pages = 1704–1710 | date = March 2018 | pmid = 29604694 | doi = 10.1121/1.5028368 | pmc = 8588570 | bibcode = 2018ASAJ..143.1704F | url = https://hal.archives-ouvertes.fr/hal-01844639/file/10.1121_1.5028368.pdf | doi-access = free }}</ref> A 2018 informational bulletin by the US [[Occupational Safety and Health Administration]] (OSHA) and the [[National Institute for Occupational Safety and Health]] (NIOSH) introduces the issue, provides examples of ototoxic chemicals, lists the industries and occupations at risk and provides prevention information.<ref>{{cite web|title=Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure|url=https://www.cdc.gov/niosh/docs/2018-124/pdfs/2018-124.pdf|access-date=4 April 2018}}</ref>

There can be damage either to the ear, whether the external or middle ear, to the cochlea, or to the brain centers that process the aural information conveyed by the ears.  Damage to the middle ear may include fracture and discontinuity of the ossicular chain.<ref>{{cite journal |last1=Hilal |first1=Fathi |last2=Liaw |first2=Jeffrey |last3=Cousins |first3=Joseph P. |last4=Rivera |first4=Arnaldo L. |last5=Nada |first5=Ayman |date=2023-04-01 |title=Autoincudotomy as an uncommon etiology of conductive hearing loss: Case report and review of literature |journal=Radiology Case Reports |language=en |volume=18 |issue=4 |pages=1461–1465 |doi=10.1016/j.radcr.2022.10.097 |issn=1930-0433 |pmc=9925837 |pmid=36798057}}</ref><ref>{{cite journal |last1=Park |first1=Keehyun |last2=Choung |first2=Yun-Hoon |date=2009-01-01 |title=Isolated congenital ossicular anomalies |url=https://doi.org/10.1080/00016480802587846 |journal=Acta Oto-Laryngologica |volume=129 |issue=4 |pages=419–422 |doi=10.1080/00016480802587846 |issn=0001-6489 |pmid=19116789|s2cid=205395847 }}</ref>  Damage to the inner ear (cochlea) may be caused by [[Bony labyrinth|temporal bone fracture]].  People who sustain head injury are especially vulnerable to hearing loss or tinnitus, either temporary or permanent.<ref>{{cite journal | vauthors = Oesterle EC | title = Changes in the adult vertebrate auditory sensory epithelium after trauma | journal = Hearing Research | volume = 297 | pages = 91–98 | date = March 2013 | pmid = 23178236 | pmc = 3637947 | doi = 10.1016/j.heares.2012.11.010 }}</ref><ref>{{cite journal | vauthors = Eggermont JJ | title = Acquired hearing loss and brain plasticity | journal = Hearing Research | volume = 343 | pages = 176–190 | date = January 2017 | pmid = 27233916 | doi = 10.1016/j.heares.2016.05.008 | s2cid = 3568426 }}</ref>