The development of the cochlear implant – sometimes referred to as a ‘bionic ear’ – was a massive step forward for hearing technology and the field of otology when it was first introduced in the late 1970s. Providing an unprecedented solution to some of the most severe forms of deafness and hearing loss, cochlear implants take the almost science-fiction-like approach of ‘hacking’ around the body’s own hearing system by surgically implanting a device which sends audio information directly into the brain. Thanks to this tiny but mighty medical device, millions of children and adults experience a better quality of life through their access to the world of sound.

How does a cochlear implant work?

Hearing is the only sense that can be successfully replicated through a medical device. Unlike hearing aids which simply amplify sound, cochlear implants deliver sound signals directly to a person’s auditory nerve, effectively bypassing damaged portions of the ear which are impairing their hearing.

 

The implant consists of an external processor that fits behind the ear to capture sound signals, and a receiver that is surgically implanted under the skin behind the ear.

 

The receiver sends signals to electrodes implanted in the cochlea (inner ear). These signals stimulate the auditory nerve, directing the signals to the brain, where they are interpreted as sounds. The implant does not restore normal hearing and may take its user three to six months to learn to interpret the signals coming from their cochlear implant. With training, people learn to recognise warning signals, understand the sounds of their environment and comprehend speech, both in person and over the phone.

 

 

 

Cochlear Implant diagram

Where it began

The multi-channel cochlear implant which is commonplace today was pioneered by Australian Professor Graeme Clark, who successfully performed the world’s first cochlear implant operation at Melbourne’s Royal Victorian Eye and Ear Hospital in 1978.

 

Clark had a keen interest in finding ways to improve, restore and even introduce hearing to patients. His work in ENT surgery, electronics and speech science played a large role in the development of the cochlear implant. 

 

On that momentous day in 1978 when his adult patient Rod Saunders heard his first words following the cochlear implant surgery, Professor Clark reported: “I was just so overcome I went into the next door laboratory and wept for joy.” He has been lauded nationally and internationally for his research.

 

 

 

Professor Graeme Clark explaining how cochlear implants function

Evolution of the cochlear implant

Following the excitement of that first successful implant four decades ago, Professor Clark further developed the cochlear implant into a 22-channel device. In 1985, the Nucleus 22 implant became the first commercially available multi-channel cochlear implant in the world. Since then, multiple iterations have come to market, boasting technological improvements that make each version more comfortable to wear and easier to use.

 

More sophisticated modern models are designed with more electrodes, which enable a wider range of pitch perceptions. Electrical current is also tightly controlled to provide a more detailed pitch. Today’s models even offer direct streaming capabilities with compatible smartphones, meaning recipients can stream phone calls, movies, and music directly to their sound processor, without needing an intermediate device like a phone clip. As of 2019, approximately 736,900 registered devices had been implanted worldwide, and that figure is projected to continue rising in the future. The World Health Organization projects that by 2030, nearly 2.5 billion people will have some degree of hearing loss, and at least 700 million (one in every ten people) will require hearing rehabilitation.

 

 

 

Performing cochlear implant surgery in an operating theatre

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