deafness

{{Main|Hearing loss}}File:International_Symbol_for_Deafness.svgs.{{Cite web |title=International Deafness Symbol |url=https://www.deafnessforum.org.au/resources/international-deafness-symbol/ |access-date=2022-11-18 |website=Deafness Forum Australia |language=en-AU}}|alt=Stylized image of an ear crossed out with a white bar on a blue background ]]In a medical context, deafness is defined as a degree of hearing difficulties such that a person is unable to understand speech, even in the presence of amplification.{{cite book|last=Elzouki|first=Abdelaziz Y|url=https://books.google.com/books?id=FEf4EMjYSrgC&pg=PA602|title=Textbook of clinical pediatrics|date=2012|publisher=Springer|isbn=9783642022012|edition=2|location=Berlin|pages=602|name-list-style=vanc|archive-url=https://web.archive.org/web/20151214195730/https://books.google.com/books?id=FEf4EMjYSrgC&pg=PA602|archive-date=2015-12-14|url-status=live}} In profound deafness, even the loudest sounds produced by an audiometer (an instrument used to measure hearing by producing pure tone sounds through a range of frequencies) may not be perceived by the person. In total deafness, no sounds at all, regardless of amplification or method of production, can be heard.

Neurologically, language is processed in the same areas of the brain whether one is deaf or hearing. The left hemisphere of the brain processes linguistic patterns whether by signed languages or by spoken languages.{{Cite web |last=Campbell |first=Ruth |display-authors=etal |date=29 June 2007 |title=Sign Language and the Brain: A Review |url=https://doi.org/10.1093/deafed/enm035 |access-date=14 Dec 2020 |pages=3–20 |doi=10.1093/deafed/enm035 |pmid=17602162 |journal=Journal of Deaf Studies and Deaf Education |volume=13}}

Deafness can be broken down into four different types of hearing loss:

• conductive hearing loss,
• sensorineural hearing loss,
• mixed hearing loss, and
• auditory neuropathy spectrum disorder.

All of these forms of hearing loss impair a person's hearing so they are not able to perceive or interpret sounds correctly. These different types of hearing loss occur in different parts of the ear, which make it difficult for the information being heard to get sent to the brain properly.

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For each of these types, there are four different levels or amounts of hearing loss. The first level is mild hearing loss. This is when someone is still able to hear noises, but it is more difficult to hear the softer sounds. The second level is moderate hearing loss, and this is when someone can hear almost nothing when someone is talking to them at a normal volume. The next level is severe hearing loss. Severe hearing loss is when someone can not hear any sounds when they are being produced at a normal level, and they can only hear minimal sounds that are being produced at a loud level. The final level is profound hearing loss, which is when someone is not able to hear any sounds except for very loud ones.{{cite web |date=21 June 2021 |title=Hearing Loss in Children |work=Centers for Disease Control and Prevention |url=https://www.cdc.gov/ncbddd/hearingloss/types.html}}

Millions of people globally live with deafness or hearing impairments. The 2005 Survey of Income and Program Participation (SIPP) indicated that fewer than 1 in 20 Americans are deaf or hard of hearing at a level that makes normal conversations difficult to hear; more than half of these people are over retirement age.{{Cite journal |last=Mitchell |first=R. E. |date=2005-10-12 |title=How Many Deaf People Are There in the United States? Estimates From the Survey of Income and Program Participation |url=https://academic.oup.com/jdsde/article-lookup/doi/10.1093/deafed/enj004 |journal=Journal of Deaf Studies and Deaf Education |language=en |volume=11 |issue=1 |pages=112–119 |doi=10.1093/deafed/enj004 |pmid=16177267 |issn=1081-4159|doi-access=free }}

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Several solutions are available for many people with hearing impairments. Hearing aids are a common device. Additionally, people may use devices that use blinking lights instead of noises for alarm clocks or other notifications.

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Cochlear implants are an option for children and adults with severe or profound hearing loss. Cochlear implants are surgically placed devices that stimulate the cochlear nerve in order to help the person hear. A cochlear implant is used instead of hearing aids in order to help when someone has difficulties understanding speech.{{cite web |date=18 July 2022 |title=Cochlear Implant Surgery |url=https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/cochlear-implant-surgery}} For children, the younger they are at the time of implantation, the better their auditory skill and perception.{{Citation |last=Gifford |first=René H. |title=Cochlear Implant Candidacy in Children: Audiological Considerations |date=2024 |work=Pediatric Cochlear Implantation |pages=77–78 |editor-last=Young |editor-first=Nancy M. |url=https://link.springer.com/10.1007/978-3-031-67188-3_2 |place=Cham |publisher=Springer Nature Switzerland |language=en |doi=10.1007/978-3-031-67188-3_2 |isbn=978-3-031-67187-6 |editor2-last=Iler Kirk |editor2-first=Karen}} Babies with confirmed bilateral profound sensorineural hearing loss may begin the surgical evaluation process for implantation as early as six months, with the US officially allowing the surgery to take place as early as nine months of age. Children with other medical problems or other types of hearing loss may be considered at a slightly older age. Parents sometimes have difficulty deciding to get cochlear implants for their child. Many felt a sense of urgency, and, in the end, most parents felt it was beneficial for their child.{{Cite web |title=Coming to a Decision About Cochlear Implantation: Parents Making Choices for their Deaf Children |url=https://login.setonhill.idm.oclc.org/login?qurl=https://doi.org%2f10.1093%2fdeafed%2fenq004 |access-date=2024-04-02 |journal=Journal of Deaf Studies and Deaf Education |doi=10.1093/deafed/enq004 | date=2010 | last1=Hyde | first1=M. | last2=Punch | first2=R. | last3=Komesaroff | first3=L. | volume=15 | issue=2 | pages=162–178 | pmid=20139157 }}

{{Main|Deaf culture}}

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In a cultural context, Deaf culture refers to a tight-knit cultural group of people whose primary language is signed, and who practice social and cultural norms which are distinct from those of the surrounding hearing community. This community does not automatically include all those who are clinically or legally deaf, nor does it exclude every hearing person. According to Baker and Padden, it includes any person who "identifies him/herself as a member of the Deaf community, and other members accept that person as a part of the community",{{cite book |last1=Baker |first1=Charlotte |last2=Padden |first2=Carol |title=American Sign Language: A Look at Its Story, Structure and Community |year=1978}} an example being children of deaf adults with normal hearing ability.

It includes the set of social beliefs, behaviors, art, literary traditions, history, values, and shared institutions of communities that are influenced by deafness and which use sign languages as the main means of communication.{{cite book |last=Padden |first=Carol |title=Inside Deaf Culture |author2=Humphries, Tom |year=2005 |publisher=Harvard University Press |isbn=978-0-674-02252-2}}{{cite journal |last=Woodward |first=James |title=Implications for sociolinguistic research among the deaf |journal=Sign Language Studies |year=1972 |volume=1 |issue=3 |pages=1–7 |doi=10.1353/sls.1972.0004}}

While deafness is often included within the umbrella of disability, members of the Deaf community tend to view deafness as a difference in human experience or itself as a language minority.{{cite book |last=Ladd |first=Paddy |url=https://books.google.com/books?id=7PRLjkES83oC |title=Understanding Deaf Culture: In Search of Deafhood |publisher=Multilingual Matters |year=2003 |isbn=978-1-85359-545-5 |page=502}}{{cite book |last=Lane |first=Harlan L. |author2=Pillard, Richard |title=The People of the Eye: Deaf Ethnicity and Ancestry |publisher=Oxford University Press |year=2011 |isbn=978-0-19-975929-3 |page=269}}{{cite journal |last=Burrows |first=Kathryn |title=The Societal Shaping of Deaf Technological Advancements |journal=Atomic Academia |date=2022 |url=https://atomicacademia.com/articles/the-societal-shaping-of-deaf-technological-advancements.117/ |doi=10.62594/AAPJ0007}}

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Many non-disabled people continue to assume that deaf people have no autonomy and fail to provide people with support beyond hearing aids, which is something that must be addressed. Different non-governmental organizations around the world have created programs towards closing the gap between deaf and non-disabled people in developing countries.

As children, deaf people learn literacy differently than hearing children. They learn to speak and write, whereas hearing children naturally learn to speak and eventually learn to write later on.{{cite journal |last1=Wong |first1=Fay |last2=Tang |first2=Gladys |last3=Li |first3=Qun |last4=Yiu |first4=Chris Kun-Man |date=2021 |title=Literacy Learning of Deaf and Hearing Preschoolers in a Sign Bilingual, Coenrollment Setting in Hong Kong |url=https://muse.jhu.edu/article/847513 |journal=American Annals of the Deaf |language=en |volume=166 |issue=4 |pages=527–553 |doi=10.1353/aad.2021.0034 |pmid=35185037 |issn=1543-0375}}

The Quota International organization, headquartered in the United States, provided immense educational support in the Philippines, where it began offering free education to deaf children in the Leganes Resource Center for the Deaf. The British organisation Sounds Seekers also supported deaf communities by offering audiology maintenance technology in hard-to-reach areas.

The Nippon Foundation supports deaf students at Gallaudet University and the National Technical Institute for the Deaf through international scholarship programmes to encourage them to become future leaders in the deaf community. The more aid these organisations give to deaf people, the more opportunities and resources marginalised people have to speak up about their struggles and aspirations. When more people understand how to leverage their privilege for marginalised groups, society can build a more inclusive and tolerant environment for future generations.

{{Main|Deaf history}}

The first known record of sign language in history comes from Plato's Cratylus, written in the fifth century BCE. In a dialogue on the "correctness of names", Socrates says, "Suppose that we had no voice or tongue, and wanted to communicate with one another, should we not, like the deaf and dumb, make signs with the hands and head and the rest of the body?"{{Cite web|title=Cratylus, by Plato|url=https://www.gutenberg.org/files/1616/1616-h/1616-h.htm|access-date=2022-02-05|website=gutenberg.org}} His belief that deaf people possessed an innate intelligence for language put him at odds with his student Aristotle, who said, "Those who are born deaf all become senseless and incapable of reason", and that "it is impossible to reason without the ability to hear".

This pronouncement would reverberate through the ages and it was not until the 17th century when manual alphabets began to emerge, as did various treatises on deaf education, such as Reducción de las letras y arte para enseñar a hablar a los mudos ('Reduction of letters and art for teaching mute people to speak'), written by Juan Pablo Bonet in Madrid in 1620, and Didascalocophus, or, The deaf and dumb mans tutor, written by George Dalgarno in 1680.

In 1760, French philanthropic educator Charles-Michel de l'Épée opened the world's first free school for the deaf. The school won approval for government funding in 1791 and became known as the "Institution Nationale des Sourds-Muets à Paris".{{Cite web|title=Institut National de Jeunes Sourds de Paris|url=https://www.injs-paris.fr/sites/www.injs-paris.fr/files/linjs_de_paris_-historique.pdf|url-status=live|archive-url=https://web.archive.org/web/20141010005252/https://www.injs-paris.fr/sites/www.injs-paris.fr/files/linjs_de_paris_-historique.pdf|archive-date=2014-10-10}} The school inspired the opening of what is today known as the American School for the Deaf, the oldest permanent school for the deaf in the United States, and indirectly, Gallaudet University, the world's first school for the advanced education of the deaf and hard of hearing, and to date, the only higher education institution in which all programs and services are specifically designed to accommodate deaf and hard of hearing students.

Parents of deaf and hard-of-hearing children often encounter difficulties when choosing an educational setting for their child. They may consider the needs and abilities of the child, how the school can make accommodations for the child, and the school environment itself.{{Cite journal |title=Decision-Making Processes of Caregivers Choosing an Educational Setting for Children Who Are Deaf or Hard of Hearing |url=https://dx.doi.org/10.1353/aad.2022.0042 |access-date=2024-03-26 |journal=American Annals of the Deaf |doi=10.1353/aad.2022.0042 | date=2022 | last1=Stephens | first1=Nicole M. | last2=Duncan | first2=Jill | volume=167 | issue=4 | pages=414–430 | pmid=36533476 }} Both the child and the parent may benefit from trial and error with different schools, to identify the best available environment.

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• Auditory neuropathy
• Auditory verbal agnosia
• Auditory-verbal therapy
• Causes of hearing loss
• Cortical deafness
• Cued speech
• Deaf hearing
• Deaf history
• Deaf plus
• Deaf rights movement
• Deaf theatre
• Deafblindness
• Deafness by country
• Deaf-community sign language
• Deaf-mute
• Diagnosis of hearing loss
• List of films featuring the deaf and hard of hearing
• Models of deafness
• World Hearing Day

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{{Reflist}}

{{Wikiversity|Global Audiology}}

• [https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss WHO fact sheet on deafness and hearing loss]
• Global audiology, International Society of Audiology
• International Ototoxicity Management Group
• [https://chosgohearing.com/blogs/news/understanding-the-5-levels-of-deafness-and-treatments 5 levels of deafness ]

{{Ear symptoms and signs}}

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Category:Deafness

Category:Hearing loss

Category:Audiology

Category:Broad-concept articles