Editing Cochlear implant (section)

==Parts==
Cochlear implants bypass most of the [[Auditory system#Peripheral auditory system|peripheral auditory system]] which receives sound and converts that sound into movements of [[hair cells]] in the [[cochlea]]; the deflection of [[Stereocilia (inner ear)|stereocilia]] causes an influx of [[Potassium#Biochemical function|potassium ions]] into the hair cells, and the depolarisation in turn stimulates calcium influx, which increases release of the [[neurotransmitter]] [[Glutamic acid|glutamate]]. Excitation of the [[cochlear nerve]] by the neurotransmitter sends signals to the brain, which creates the [[experience]] of sound. With an implant, instead, the devices pick up sound and digitize it, convert that digitized sound into electrical signals, and transmit those signals to electrodes embedded in the cochlea. The electrodes electrically stimulate the cochlear nerve, causing it to send signals to the brain.<ref name=2016Horizon>{{cite journal | vauthors = Roche JP, Hansen MR | title = On the Horizon: Cochlear Implant Technology | journal = Otolaryngologic Clinics of North America | volume = 48 | issue = 6 | pages = 1097–1116 | date = December 2015 | pmid = 26443490 | pmc = 4641792 | doi = 10.1016/j.otc.2015.07.009 }}</ref><ref name=NIDCD2016/><ref name=2015f1000>{{cite journal | vauthors = Yawn R, Hunter JB, Sweeney AD, Bennett ML | title = Cochlear implantation: a biomechanical prosthesis for hearing loss | journal = F1000Prime Reports | volume = 7 | pages = 45 | year = 2015 | pmid = 26097718 | pmc = 4447036 | doi = 10.12703/P7-45 | doi-access = free }}</ref>

There are several systems available, but generally they have the following components:<ref name=2016Horizon/><ref name=2015f1000/>

External:

* one or more microphones that pick up sound from the environment
* a speech processor which selectively [[Filter (signal processing)|filters]] sound to prioritize [[Speech communication|audible speech]]
* a transmitter that sends power and the processed sound signals across the skin to the internal device by [[Transmitter|radio frequency transmission]]

Internal:

* a receiver/stimulator, which receives signals from the speech processor and converts them into electric impulses
* an electrode array embedded in the cochlea
A [[totally implantable cochlear implant (TICI)]] is currently in development. This new type of cochlear implant incorporates all the current external components of an audio processor into the internal implant. The lack of external components makes the implant invisible from the outside and also means it is less likely to be damaged or broken.<ref>{{cite journal | vauthors = Cohen N | title = The totally implantable cochlear implant | language = en-US | journal = Ear and Hearing | volume = 28 | issue = 2 Suppl | pages = 100S–101S | date = April 2007 | pmid = 17496658 | doi = 10.1097/AUD.0b013e31803150f4 | s2cid = 38696317 | doi-access = free }}</ref>
[[File:Cochearimplants.JPG|thumb|Internal components of a conventional device (not yet implanted)]]

=== Assistive listening devices ===
Most modern cochlear implants can be used with a range of [[assistive listening device]]s (ALDs), which help people to hear better in challenging listening situations. These situations could include talking on the phone, watching TV or listening to a speaker or teacher. With an ALD, the sound from devices including mobile phones or from an external microphone is sent to the audio processor directly, rather than being picked up by the audio processor's microphone. This direct transmission improves the sound quality for the user, making it easier to talk on the phone or stream music.

ALDs come in many forms, such as {{not a typo|neckloops}},<ref>{{Cite web|title=Induction Neckloops - Bluetooth Neckloop|url=https://adcohearing.com/collections/induction-loops-neckloops|access-date=2021-12-09|website=ADCO Hearing Products|language=en}}</ref> pens,<ref>{{Cite web|title=Phonak Roger Pen|url=https://www.ihear.co.uk/products/phonak-roger-pen|access-date=2021-12-09|website=www.ihear.co.uk|language=en|archive-date=2021-12-09|archive-url=https://web.archive.org/web/20211209161908/https://www.ihear.co.uk/products/phonak-roger-pen|url-status=dead}}</ref> and specialist battery pack covers.<ref>{{Cite web|title=AudioStream - Connect Your MED-EL Cochlear Implant|url=https://www.medel.com/hearing-solutions/accessories/connectivity/audiostream|access-date=2021-12-09|website=www.medel.com|language=en}}</ref> Modern ALDs are usually able to receive sound from any Bluetooth device, including phones and computers, before transmitting it wirelessly to the audio processor. Most cochlear implants are also compatible with older ALD technology, such as a telecoil.<ref>{{Cite web|date=2012-03-29|title=Using the telephone|url=https://cochlearimplanthelp.com/journey/getting-connected/using-the-telephone/|access-date=2021-12-09|website=cochlear implant HELP|language=en}}</ref>