[2] Through everyday listening and auditory training, cochlear implants allow both children and adults to learn to interpret those signals as speech and sound.

The inside component, the actual implant, has a coil to receive signals, electronics, and an array of electrodes which is placed into the cochlea, which stimulate the cochlear nerve.

Many users of modern implants gain reasonable to good hearing and speech perception skills post-implantation, especially when combined with lipreading.

In the late 1960's Robin Michelson and colleague Melvin Bartz construct a cochlear device with biocompatible materials that can be implanted in human patients.

Michelson, a clinical pioneer, and Merzenich, a talented basic scientist with a solid foundation in neurophysiology, was an integral element in the development of the UCSF cochlear implant team.

[18] In 1973, the first international conference on the "electrical stimulation of the acoustic nerve as a treatment for profound sensorineural deafness in man" was organized in San Francisco.

This work took place over three years, when Kissiah would spend his lunch breaks and evenings in Kennedy Space Center's technical library, studying the impact of engineering principles on the inner ear.

[21] Cochlear implants bypass most of the peripheral auditory system which receives sound and converts that sound into movements of hair cells in the cochlea; the deflection of stereocilia causes an influx of potassium ions into the hair cells, and the depolarisation in turn stimulates calcium influx, which increases release of the neurotransmitter glutamate.

[28] Modern ALDs are usually able to receive sound from any Bluetooth device, including phones and computers, before transmitting it wirelessly to the audio processor.

[36] However, the potential cost of a postoperative infection is high (including the possibility of implant loss); therefore, a single preoperative intravenous injection of antibiotics is recommended.

[38] To avoid the risk of bacterial meningitis, the CDC recommends that adults and children undergoing CI receive age-appropriate vaccines that generate antibodies to Streptococcus pneumoniae.

[42] As cochlear implant surgical techniques have advanced over the last four decades, the global complication rate for CI surgery in both children and adults has decreased from more than 35% in 1991 to less than 10% at present.

[43][44][45] The risk of postoperative facial nerve injury has also decreased over the last several decades to less than 1%, most of which demonstrated complete return of function within six months.

[47] CI rarely results in significant or persistent adverse effects on the vestibular system when hearing conservation surgical techniques are practiced.

[49] Multiple meta-analyses of the literature from 2018 showed that CI users have large improvements in quality of life after cochlear implantation.

[55] They also tend to hold mostly positive attitudes towards their cochlear implants,[56] and as a part of their identity, a majority either do "not really think about" their hearing loss, or are "proud of it.

[59] A 2019 study found that bilateral cochlear implantation was widely regarded as the most beneficial hearing intervention for acceptable candidates, although it is more likely to be performed and reimbursed in children than adults.

[61][62][63] Research since then has reported long-term socio-economic benefits for children as well as audiological outcomes including improved sound localization and speech perception.

A 2016 research study found that age at implantation was highly correlated with post-operative speech understanding performance for various test measures.

In this study, people who were implanted at age 65 or older performed significantly worse on speech perception testing in quiet and in noisy conditions compared to younger CI users.

[72][73] The effects of aging on central auditory processing abilities are thought to play an important role in impacting an individual's speech perception with a cochlear implant.

However, a study found no statistical difference in the speech understanding abilities of CI patients over 65 who had been hearing impaired for 30 years or more prior to implantation.

[70] In general, outcomes for CI patients are dependent upon the individual's level of motivation, expectations, exposure to speech stimuli and consistent participation in aural rehabilitation programs.

All of these services, as well as the cochlear implant device and related peripherals, are part of the medical intervention and are typically covered by health insurance in the United States and many areas of the world.

[81][82] In the United Kingdom, the NHS covers cochlear implants in full, as does Medicare in Australia, and the Department of Health[85] in Ireland, Seguridad Social in Spain, Sistema Sanitario Nazionale in Italy, Sécurité Sociale in France[86] and Israel, and the Ministry of Health or ACC (depending on the cause of deafness) in New Zealand.

A study in Colombia assessed the lifetime investments made in 68 children who received cochlear implants at an early age.

[91][92] In Europe, Africa, Asia, South America, and Canada, an additional device manufactured by Neurelec (later acquired by Oticon Medical) was available.

Some in the deaf community call cochlear implants audist and an affront to their culture, which, as they view it, is a minority threatened by the hearing majority.

They believe that measuring a child's success only by their mastery of speech will lead to a poor self-image as "disabled" (because the implants do not produce normal hearing) rather than having the healthy self-concept of a proudly deaf person.

The first children to receive cochlear implants as infants are only in their 20s (as of 2020), and anecdotal evidence points to a high level of satisfaction in this cohort, most of whom don't consider their deafness their primary identity.