Thursday 01 Dec 2016

Bionic Hearing: The Science and the Experience

Imagine never having heard the voice of your loved one. 

This may seem like an impossible challenge. Hearing is something we take for granted and perhaps only once it is gone can we truly realise what it means to us all. Ian Shipsey, particle physicist and Professor of Physics at Oxford University, lost his hearing in 1989 as a result of treatment for Acute myeloid leukaemia. But thanks to cochlear implants, the loss was reversed. 

Afterwards he heard the sound of his daughter’s voice for the first time: “There are no words in any language to describe how wonderful it was,” Shipsey told the audience of 60 students from La Grande Boissière Secondary School who attended his conference at the Centre des Arts on 18 and 21 November. 

Around ten percent of people lose their hearing at some stage of their life. It can happen for a number of reasons; it can be hereditary, prolonged exposure to loud sounds, old age, infections or drugs, and even due to chemotherapy, as in Shipsey’s case.

A Short History of Cochlear Implants 

The groundwork towards the first cochlear implant was paved in the late 18th century. Alessandro Volta, the inventor of the battery, managed to stimulate his auditory nerve by connecting a battery of approximately 50V to two metal rods that he stuck into his ears. What followed was what Volta described as a “boom within the head”, supposedly followed by a sound described as “the boiling of thick soup”. 

What followed were many years of testing and innovation which finally led to the first marketable cochlear implant in 1972. Over 1,000 of the House 3M single-electrode implant were implanted in the 1970. 

Nowadays, approximately 324,000 people worldwide have received implants. 

Unlike hearing aids, which amplify sound, cochlear implants replace the damaged parts of the ear and stimulate the auditory nerve. Sound is first caught by an external microphone, often kept behind the ear. The sound is then passed on to a series of electrodes inside the cochlea which in turn trigger the auditory nerve. And voila! The sound is heard. 

Shipsey explained that the brain is so flexible that adults who have previously been able to hear can understand 80% of speech after only six months of living with an implant. 

Cochlear implants do not spell the death knell for deafness however. Shipsey realised he was beginning to go deaf when he “could no longer hear the quiet passages of music.” Modern implants can help deaf people reconnect linguistically, but the ability to enjoy music is limited as they cannot regain a sense of pitch. The procedure is also expensive. In the United States, it costs between $60,000 to $100,000 to get an implant. 

With the recent opening of the LGB STEM Centre in September 2016, Shipsey’s conference falls within the framework of Ecolint’s renewed commitment to innovative ways of teaching STEM subjects. As a benchmark of medical engineering, cochlear implants stand at the crossroads of science, technology and medicine – a prime example of an interdisciplinary exploit from which our students can inspire themselves.

Shipsey is using his experience as a call to action to spread the word about cochlear implants. Of 20 million deaf people born worldwide, only 220,000 are benefiting from cochlear implants. 

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