even for sighted people – is fascinating. There are two prototypes being developed to suit the needs of different patient groups.

The first prototype bionic eye, known as the wide-view device, will use around 100 electrodes to stimulate the nerve cells in the back of the eye. This will allow people with severe vision loss to see the contrast between light and dark shapes regain mobility and independence. This device may be most suitable for retinitis pigmentosa patients.

The second prototype, known as the high-acuity device, will use 1000 electrodes to stimulate the retina and will provide patients with more detailed information about the visual field, helping them recognize faces and even read large print. The high-acuity device may be most suitable for patients with age-related macular degeneration; however, it is still some years before the first patient tests will commence.

Melbourne researchers working to restore sight to the vision impaired believe diamond is the best material with which to build a bionic eye and hope to have a prototype in testing within the next few years.

Kumar Ganesan, a physicist helping to design a bionic eye for Bionic Vision Australia at the University of Melbourne, says metals such as platinum and iridium are currently used for implants. He says even the hardest metals deteriorate within five to 10 years, which is why researchers have turned their focus to diamonds.

“We made a diamond device so the implant inside the eye will not deteriorate or will not be damaged by any other means,” he said.

2.9. Future Scope

Researchers are already planning a third version that has 1,000 electrodes on the retinal implant, which they believe could allow for facial-recognition capabilities and hope to allow the user to see colorful images. Scientists believe the immediate goal after achieving above is to develop a functioning artificial retina with resolution that mimics human sensors. Once this step has been achieved, they says, then attention can be brought to bear on color vision, followed by the replacement of some of the interconnecting neural cells that lead to the optic nerve. So, let us hope to reach all these goals as soon as possible.

The researchers note the device has some limitations, and it will not restore perfect vision. However, they are sure it will give people the advantage of having a general sense of their surroundings.

15

2.10. Bionic Eyes Do More Than Prosthetic Eyes

A bionic eye is not the same thing as a prosthetic eye. Prosthetic eyes (also called “glass eyes” or “artificial eyes”) replace the physical structure and appearance of an eye that must be removed due to trauma, pain, disfigurement or disease. Bionic eye implants, on the other hand, work inside the existing eye structures or in the brain. They are designed to achieve functional vision goals – as opposed to physical, cosmetic ones.

The Argus II Retinal Prosthesis System consists of a tiny eyeglasses-mounted camera and a transmitter that wirelessly sends signals to an electrode array that is implanted onto the damaged retina of a blind person.

Just as there is no single cause for blindness, there's likewise no one cure. To determine whether a bionic eye could help you see, it's important to know the reason(s) for your vision loss. In some cases, the cornea or lens are damaged or diseased, or the retina can't perceive light. In others, the signal is lost somewhere along the visual pathway in the brain.

Different bionic eye models take aim at different target areas in the visual pathway. Currently, retinal implants are the only approved and commercially available bionic eyes, though cornea transplants and cataract surgery can replace the cornea and lens if these structures are clouded or are incapable of focusing light for other reasons.

2.11. Limitations of Bionic Eyes

Although the Argus II system enables people to discern light, movement and shapes, it does not yet restore sight to the extent some might hope. This limitation is largely due to the fact that the current implant has only 60 electrodes. To see naturally, you'd need about a million.

However, some Argus II users can function well enough to read large-print books and cross the street on their own. And the company plans to add more electrodes in future models.

Another limitation of the current Argus II Retinal Prosthesis System is that it doesn't enable users to perceive colors. And it's expensive – costs associated with the device and procedure add up to nearly $150 000 and may or may not be covered by medical insurance.

Future iterations of the Argus II system will likely feature advanced implants with higher numbers of electrodes that are capable of producing sharper, more functional vision for people who are blind from retinitis pigmentosa and other reti-

16

nal diseases, including macular degeneration. It's possible future implants may also be able to produce some degree of color vision.

In addition to Second Sight's bionic eye, researchers elsewhere are testing devices with even more electrodes, as well as devices that bypass the retina and stimulate the brain directly.

2.12. Bionic ears

Hearing is a sense most of us take for granted, but in reality it resembles a convoluted, anatomical version of the board game Mousetrap, played out within the fiendishly intricate architecture of the ear.

The ball is set rolling when sound waves arrive at the outer ear and are funnelled down the ear canal where they end up banging into the eardrum. The vibrations from the eardrum move a tiny connected bone called the hammer, which is hooked up to further biological ironmongery in the form of the anvil which is linked to the stirrup. The latter rests against part of the inner ear which leads on to the spiral-shaped cochlea.

And it is within the cochlea that things get technical. As the stirrup vibrates, it causes fluid within the inner ear to move back and forth – motion that is picked up by a membrane and passed on to tiny hair cells inside the cochlea. When the hair cells waggle, they release chemicals known as neurotransmitters that trigger electrical impulses in auditory nerve fibres close by. These signals whiz along the auditory nerve to the brain where they are deciphered. Perhaps surprisingly the hair cells, and hence auditory nerve fibres, are laid out like a piano keyboard – those in the outer part of the cochlea's spiral respond to high frequency sound, while those near the tight curl at the centre react to low frequencies.

There is no doubt it's a complex set-up, and one of evolution's finest achievements. But when something goes wrong, the consequences can be devastating.

Boasting an array of highly sophisticated technology, these implants have unsurprisingly been called “bionic ears”. Their staggering ability to create a sense of sound is down to a flexible electrode array that is gently nestled inside the cochlea during surgery. Finer than fishing twine, these wires allow the conventional auditory pathway to be sidestepped, changing the lives not only of those with ANSD, but also those with the missing or damaged hair cells or a damaged auditory nerve typical of “sensorineural” hearing loss.

Let's reset the Mousetrap. Now sounds are picked up by an external microphone, hooked over the ear, and turned into a digital “score” of electronic stimulation patterns by a processor. This information is then transmitted wirelessly across

17

the scalp, together with a dose of energy, where it is picked up by a coil under the skin and passed to the implant where the digital score is converted into electrical pulses. These are sent to the electrodes within the cochlea, where they artificially trigger electrical impulses in the auditory nerve fibres, bypassing the role of the hair cells. But while each hair cell stimulates only a few of these fibres, the electrical pulses of a cochlear implant trigger much larger areas. It's a bit like playing a piano with giant hands – big bunches of keys get hit all at once. Yet, wonderfully, the mechanism works. It's elegant, it's sophisticated, and it changes lives.

Yet it is technology that, nearly 40 years ago, barely seemed possible. “In the very beginning there was a lot of scepticism, mostly by neurophysiologists,” reveals Professor Ingeborg Hochmair when we meet in the swish surroundings of the Med-El innovation centre in Innsbruck, Austria. “They couldn't believe it could work to stimulate just a few locations in the cochlea, and by stimulating around eight to 20 or so locations replace the function of 25 000 nerve fibres which there are in a normal auditory nerve,” she says. “But it works.” As CEO of Med-El, one of the biggest cochlear implant companies worldwide, Hochmair is recognised as a pioneer of the technology – an accolade that last year saw her share the Lasker prize, an international award in the field of medical research.

The new innovation centre, a futuristic-looking construction opened just last year, is a testimony to the success of her vision and hard work. But the process of constructing a cochlear implant is also impressive. Few parts of the process are automated, and it is claimed that if a user tells the company the number of their implant, Med-El can pinpoint the people who built it. It's a handmade device for a very personal application.

And it is a cause to which Ingeborg Hochmair has devoted her life. Having decided at just 13 years old that she wanted to pursue a career in biomedical technology she went on to study electrical engineering in Vienna. It was there that she and her future husband, Erwin Hochmair, became involved in the nascent field of cochlear implantation. Working with researchers, surgeons and, crucially, patients, they soon notched up an impressive list of successes, and in 1990 began employing staff at Med-El. “As inventors we wanted to see this become available for potential users,” she says. At the time both were employed in academia, which Ingeborg later left to head the growing company. She believes their mutual passion for the technology has contributed to her success. “This is a very lucky constellation,” she says of the partnership.

But while the technology has developed in leaps and bounds, Hochmair believes there is more to do. “There are still so many children that still have no access

18

to the technology in various countries.” And financial outlay is not the only reason. “It's awareness: many families just don't know about that possibility. It's infrastructure in some countries,” she says.

With children, it is a race against time. For those born unable to hear, it is crucial to implant the devices at a young age, preferably before two years old and ideally nearer nine months, to maximise the child's ability to develop speech, language and listening skills. Without the input of auditory signals, the brain does not fully develop the ability to decipher sound, and as time ticks by this capacity for change– known as plasticity – decreases. What's more it has been suggested that, if unused, these areas of the brain gradually become reassigned to tackling other tasks.

Even with a cochlear implant, there are further hurdles to face in harnessing the technology. “Somebody told me once that [having] a cochlear implant is a bit like being handed a key to a Porsche and not knowing how to drive,” says Anita Grover. “The brain has access to all this sound but it has to really learn to make sense of it.”

As chief executive of Auditory Verbal UK, a charity that provides therapy to youngsters getting to grips with their bionic ears, Grover is passionate about helping others to make the most of the technology. “I would like all children whose family wants them to be able to listen, speak and achieve to have access to auditory verbal therapy to help them maximise the potential of their cochlear implants,” she says. “There is a very small window where there is plasticity in a young brain, which means there is a real opportunity to maximise the development of listening and spoken language. If you get the early intervention right with the right technology and habilitation then you get the opportunity for deaf children to realise their potential. And that potential should be the same as a hearing child.”

Grover is well acquainted with the technology. Having experienced progressive hearing loss, by her late 20s hearing aids were no longer helping. As a civil servant she had relied heavily on lip-reading, but it was far from ideal. “I would be in a meeting [with] 15 to 20 people around the table and it was like Wimbledon,” she says. “It's so incredibly tiring – you’ve got no backup.” In the end, a cochlear implant became necessary. “Without a cochlear implant I hear nothing at all, absolutely nothing,” she says. “It changed my life. I had gone through that process of my hearing deteriorating whereby I was becoming more and more withdrawn. I wouldn’t want to be in a social situation for fear of missing part of the conversation or something having been said, or perhaps getting the pitch wrong – shouting in a quiet place or being quiet in a noisy place.” And there are sounds you would

19

never want to miss. “When the first of my twins was born he came out screaming,” says Grover. “I would not have heard that if I didn't have a cochlear implant.”

But adults are in danger of being overlooked. Recent figures from the charity Action on Hearing Loss reveal that one sixth of the UK's adult population have some form of hearing difficulties while a 2013 study suggested only 5 % of adults whose life could have been improved by cochlear implants actually had received one. “For adults, I would like to see improved access to at least one implant and ideally two,” says Grover.

It's the dark side of the success story. Policy introduced in 2009 by the National Institute for Health and Care Excellence (Nice) dictates that while children deaf in both ears should receive two implants as a matter of routine, adults are allowed only one – unless they have a second disability, such as blindness, that makes them more reliant on hearing. It's an issue that Labour MP Lilian Greenwood put squarely to the House of Commons in November. “A growing body of evidence indicates that bilateral implants provide added improvements in speech perception in noisy environments over unilateral implantation, and better sound localisation, leading to improved quality of life,” she said.

Users such as Stuart McNaughton, a lecturer at Westminster Business School who also works for cochlear implant firm Advanced Bionics, say adults deserve better. “I pushed for two years [for] the NHS to give me the second one,” he tells me over coffee amid the bustle of Waterloo station. “Because I teach, part of my livelihood is very dependent on my ear working and, you know, sometimes things go wrong and if the one ear that you've got goes wrong you lose your livelihood.” Fundamentally, he says, it is about experiencing the world those of us who can hear take for granted. “It makes me the way I should have been, the way you are.”

But McNaughton is one of a small group of adults with bilateral cochlear implants. And like Greenwood, he believes it is high time attitudes towards adults changed. “I understand that children need more input because they are developing language and they are developing skills, but what about all the people over the age of 18, 19, 20, 21? They should be allowed bilateral implants as well. Society puts pressures on adults too – relationships, jobs –it's a rat race out there.”

It's a call to arms that resonates across the medical profession. As Shaida explains: “Two ears are better than one. Two cochlear implants are better than one.” The situation is particularly desperate for patients who have suffered from meningitis. “With meningitis you often get obliteration of the cochlea,” he says. “Normally for the meningitis patients we fast track them so that we can get the implant in as fast as possible before the cochlea becomes completely blocked and it's im-

20

possible to do an operation.” For such patients simultaneous bilateral implantation could be crucial. “If we came back later on to implant the other side because the first side had failed, it [may not] be possible because of the blockage.”

But the 2009 Nice guidelines made it clear: even in such situations simultaneous bilateral implantation was simply not an option.

The introduction of the guidelines had also fuelled fears of deepening inequalities. “What we are seeing is a number of patients are opting to have one done on the NHS and having the second one done privately. Which is great – if you can afford it,” said Shaida.

David Selvadurai, consultant otolaryngologist surgeon at St George's hospital, London, also believes it is time for change. “As a community of professionals we are keen to push this forward and we would like to see bilateral implants in adults become more acceptable,” he says.

But with the guidelines only reviewed every few years, he believes timing is everything. “What we don't have at the moment is good cost benefit data to show that there's enough benefit to the individual to demonstrate cost effectiveness for the NHS,” he says. “The danger that we have to be wary of is that the guidelines are reviewed before the necessary evidence is available.”

It's a situation Shakeel Saeed, professor at UCL and the Royal National Throat, Nose and Ear hospital is determined to change. Working with colleagues at the Ear Institute, he is currently scoping a national, multi-centre prospective study on bilateral cochlear implantation in adults. “This is to create high quality evidence that Nice can then use to make a considered decision.” Gathering the evidence, he says, will take four to five years – and it won't be cheap. But it's a chance they can't afford to miss.

“If we complete that study then we will be able to answer a very simple question: does the benefit of having two implants in adults justify the cost?” says

Saeed. “We might find it doesn't – but I suspect that we will find that it does.” Bionic ears are a technological triumph. It's time adults, like children, were

permitted to experience the full measure of their metamorphic potential.

Many technological breakthroughs that have changed our daily lives, like the internet, are rooted in researches carried out by Defense Advanced Research Projects Agency. As robotic technologies and their applications are pretty novel, sometimes significant researches in these fields are funded by DARPA. The bionic arm is not an exception.

So, Revolutionizing Prosthetics Program funded two separate projects – a two-year project Revolutionizing Prosthetics 2007 and a four-year Revolutionizing

21