Recent news of a bionic eye prototype being tested by Bionic Vision Australia is exciting for medical device research in Australia. There are a number of other ‘retinal prosthesis’ devices being developed in Australia and overseas. This competition between different ideas and systems indicates the time is right for this concept to flourish.
The bionic eye is often compared to the cochlear implant. Both are small implantable devices that electrically stimulate nerves and create the perception of vision or sound in the brain. It’s 35 years since the first cochlear implant prototype was successfully implanted in Australia in 1978. Now that it is so widely used it is easy to forget the years of hard work by so many people that preceded the development. Looking back at this story gives us an insight into how the bionic eye may eventually develop.
In a cochlear implant system the external speech processor detects sound and converts it to digital code. It transmits this code through the skin to the implant. The implant converts this code into electrical impulses that are sent to the electrode and stimulate the hearing nerve in the cochlea. The brain then interprets these electrical impulses as sound.
The Powerhouse Museum collection includes a prototype of the cochlear implant and external speech processor designed and made by Dr Graeme Clark and his team at the University of Melbourne in 1979. One of only a few made this ‘gold box’ prototype implant comprises a gold-coated stainless steel box containing the electronics with a red copper coil as the receiver coated in a package of silicone. It is the same design as the prototype implanted in the second test patient, George Watson, in July 1979. It was initially a success and he was able to hear sounds and speech proving the effectiveness of the implant design and speech processing idea and justifying further funding for a clinical trial. But in early 1980 the implant stopped working and when it was later removed and analysed the failure that was found informed the design of the first commercial system for clinical trials in 1982. This technology formed the basis for the company now known as Cochlear Ltd.
The Museum’s collection also includes the ‘Mini’ implant, the first of its kind designed specifically for children. The Nucleus 24 Contour implant released in 2000 featured a curved electrode making the implant surgery simpler and less invasive. Much thinner than the early prototype, the current generation of implants are highly reliable – over 98% reliable with more than 90 000 implants over the last eight years.
As well is improving the implant design there have been significant improvements in the external speech processor design and software. The Museum’s collection includes the first prototype portable speech processor, PSP-1, that allowed the recipient to move around rather than being attached to a computer in the lab. It was used by the two test patients to demonstrate the speech processing idea at a media conference in 1980. Housed in a leather carry bag it required a hand held microphone to pick up sound and a headband held the transmitter in place over the implant.
The first commercial speech processor was a much smaller wearable device. Worn discreetly on the hip or under clothes the microphone was attached to a headband which also kept the transmitter in place over the implant. It was the first of a number of generations of devices produced by Cochlear with continual improvements in sound processing and reduction in size. This allowed recipients to take advantage of improvements in speech processor technology without surgically replacing their implant. Over the following years the wearable speech processors shrunk to fit behind the ear (BTE) and improvements in speech processing software reduced background noise. The speech processors have become water resistant and a Hybrid system combines the implant with a conventional hearing aid.
In 2009 the first remote assistant or remote control for the Cochlear system was introduced. It allows the patient to monitor and control the speech processor settings rather than visiting a speech clinic for regular adjustment. The remote assistant is on display at the Powerhouse Museum in the 2013 Australian International Design Awards exhibition. The most recent version Nucleus 6 has bluetooth capability to link with audio devices.
Also on display in this exhibition is the Cochlear Nucleus Intraoperative Remote Assistant which received the Powerhouse Museum Design Award at the Australian International Design Awards ceremony in May. The hand held device is used in the operating theatre to test the implant before the recipient leaves theatre. It enables faster testing saving time for the patient while under anaesthetic and removes the need for bulky wires and computers in the operating theatre. Easy to set up and use an unskilled operator can test the implant without requiring expert audiological or electrophysiologist time. The device can potentially increase the efficiency and effectiveness of cochlear implant surgery. It may also allow surgery to be performed in locations where access to audiological experts is limited.
Cochlear implant technology and bionic eye innovations are now converging and influencing each other. A totally implantable cochlear implant including implantable battery processor and microphone has been under development by several companies for some time. Restoring hearing loss through stem cell therapy is also on the longer term horizon.
But the bionic eyes, ears and other body parts are here to stay. In the ‘bionic future’ people may utilise a number of implanted and wearable electronic devices to assist and enhance their bodies. These devices may talk to each other and some can already communicate the status of the body to users and networks outside the body.
Since the early prototype of the cochlear implant system was developed it has become smaller more reliable and more effective due to advances in materials, technology, software design and surgical techniques. Reflecting on these changes provides a sense of what currently emerging bionic technologies may become in the future.