Deafness

== Medical context ==
{{Main|Hearing loss}}[[File:International_Symbol_for_Deafness.svg|thumb|The International Symbol for Deafness is used to identify facilities with hearing augmentation services, especially [[Assistive listening device|assistive listening devices]].<ref>{{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}}</ref>]]In a medical context, deafness is defined as a degree of hearing difference such that a person is unable to understand speech, even in the presence of amplification.<ref name="Peads2011">{{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}}</ref> In profound deafness, even the highest intensity sounds produced by an [[audiometer]] (an instrument used to measure hearing by producing pure tone sounds through a range of frequencies) may not be detected. 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.<ref name=":0">{{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}}</ref>

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 cause an impairment in a person's hearing where they are not able to hear 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. To break it down even further, there are three different levels of hearing loss. According to the CDC, 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 minimum 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.<ref>{{cite web |date=21 June 2021 |title=Hearing Loss in Children |url=https://www.cdc.gov/ncbddd/hearingloss/types.html}}</ref>



There are millions of people in the world who are living with deafness or hearing impairments. Survey of Income and Program Participation (SIPP) indicate that fewer than 1 in 20 Americans are currently deaf or hard of hearing.<ref>{{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 }}</ref>  There are a lot of solutions available for people with hearing impairments. Some examples of solutions would be blinking lights on different things like their phones, alarms, and things that are important to alert them. Cochlear implants are an option too.<ref>{{cite web |title=Know-the-ADA |url=https://know-the-ada.com/t4/history-deafness.html}}</ref> 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.<ref>{{cite web |date=18 July 2022 |title=Cochlear Implant Surgery |url=https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/cochlear-implant-surgery}}</ref>