Prosthetics for the 21st century
David Gow, inventor of the
world's first bionic hand
An episode of the BBC television programme called ‘Tomorrow's World' inspired David Gow to leave his job working for a Scottish defence contractor. Aired in 1980, the show featured scientists who developed electrically powered artificial limbs. It rekindled the early fascination with prosthetics Gow had developed as an engineering student, sketching designs for bionic arms and legs.
Fast-forward to the present, and Gow has made a name for himself as the inventor of one of the world's most sophisticated patented prosthetics.
Decades of dedication
Congenital limb defects or losing a limb through an accident can severely impede individuals in carrying out day-to-day tasks. Fortunately, thanks to technological advances in components and materials, prosthetics are both lighter and stronger than ever.
In addition, prosthetics wearers across the world benefit greatly from the ingenuity of inventors such as David Gow, which enables them to lead more active, independent lives.
Following his graduation from the University of Edinburgh in 1979 and a brief stint with a defence contractor, Gow applied for an engineering position at the Bioengineering Centre at Princess Margaret Rose Hospital in Edinburgh in 1981.
More than a decade of dedication and hard work at the centre eventually resulted in international recognition for a partial hand system in 1993, and the world's first electrically powered shoulder, pioneered in 1998.
Creating a functional prosthetic hand
In early 2003, Gow founded the company Touch EMAS. The transition from operating as a public body within the Scottish National Health Service to a private company enabled him to attract venture capital to fund further research. In 2005, the company was renamed Touch Bionics and, in 2007, unveiled the world's first fully articulating bionic hand - the iLIMB Hand.
The iLIMB Hand is controlled by the electric signals its wearer creates by moving the muscles in the residual limb, a principle first commercialised by Russian scientists in 1964.
When a person wearing the iLIMB contracts a muscle, slight electric signals are transmitted to a computer in the hand of the prosthesis, which interprets the signals and activates the appropriate motors to achieve the desired hand gesture. The outer chassis consists of light-weight aluminium that can be covered in a skin-like material that matches the wearer's natural skin tone.
Initially, Gow pursued the conventional method of using a centralised motor system to control the many different gestures and movements a prosthetic hand has to perform. However, this approach failed to deliver the intricate motion he envisioned, which would allow for the complex articulation of every individual finger. In addition, a centralised motor is difficult to scale down to fit into a prosthetic hand small enough for a child.
The breakthrough came when Gow abandoned the concept of a centralised motor system entirely and instead decided to equip each individual digit with its own motor.
Freedom within your grasp
Wearers of the modular iLIMB HAND are able to experience a much wider range of motion from their prosthetic hand. Previously unobtainable grip positions are now possible through the fully articulating prosthetic.
Gow's invention significantly improves upon previous prosthetics, which were often cumbersome and relatively conspicuous due to their limited functionality.
"We have broken through the barrier of making a hand that has to look like a medical device," said Gow.
Although his novel, modular approach also came with new set of challenges - including gearing, motor design and the specialised control software needed for the operation - Gow's innovative design has proven popular. Touch Bionics recorded more than 100% growth in the period from 2008 to 2009, and in just three years since its release, the iLIMB Hand has been fitted to more than 1,400 patients worldwide.
Donal McKillop is one such wearer of the iLIMB Hand. Having lost his right arm in an accident at home 35 years ago, he was one of the first people to be fitted with an iLIMB in 2007. Of the impact of the iLIMB Hand on his life he simply says, "It's a hand I never thought I would have again."
Gow's technology quickly gained international recognition. In 2008, the iLIMB Hand was named one of the top 50 innovations of the year by Time Magazine. Touch Bionics has since unveiled bionic fingers and has acquired the US company LIVINGSKIN, a specialist in providing lifelike prosthetic coverings made out of silicone.
While Touch Bionics leads this specific market segment of prosthetics, selling approximately 500 iLIMB Hands per year, another British company - RSLSteeper - launched its own bionic hand in November of this year, claiming it to be the world's most advanced bionic hand.
Other competitors vying for the estimated 4,000 to 5,000 prosthetic hands sold yearly in the European Union, North America and Japan are the German prosthetics companies Otto Bock and Vincent Systems.
Securing a patent has thus been vital to safeguarding Gow's technological achievement. "The patenting process we've gone through over the last ten to 12 years has been vital to protecting the future of the iLimb hand and making sure that the company could bring it to market," he said.
Dedicated to the cause
David Gow left Touch Bionics in 2009 to become Head of SMART Services at NHS Lothian, with responsibility for rehabilitation technology services for South East Scotland. His invention continues to have an impact in the technology developed by Touch Bionics and on the patients whose lives it has improved.
"I spent my career developing something which would actually benefit people, and it wasn't a theory - it was actual reality. And I think when you put that together, it gives you a huge degree of feel-good factor," Gow said.
How it works
There are three general groups of artificial limb: cosmetic, body-powered, and myoelectric.
Only the latter two are functional prosthetics, which can be actively moved and used by the person wearing them. Body-powered or cable-controlled prostheses, used for upper limbs, are attached to the body via a harness. Gripping - or releasing - works through physical movement via a cable to the terminal end of the prosthesis.
In comparison, myoelectric
prostheses require a motor system, gears and a power source to drive movement,
resulting in prosthetics that are quite a bit heavier than cosmetic or
Gow pioneered the idea of modularising the motor system within a prosthetic hand instead of using a single centralised motor. Each digit contains a self-contained module including a Direct Current (DC) motor that uses electricity from an integrated battery to produce torque.
In addition, an innovative gear system that enables a powerful grip and fast movement is fitted. A built-in stall detection system recognises when each finger has achieved sufficient grip and stops its motor, preventing further power consumption and extending battery life.
The person wearing the prosthetic is trained in triggering muscular movement in their residual limb, sending electric pulses that are picked up by skin-mounted electrodes. Different pulse combinations can be programmed to specific grip combinations, enabling the patient to control the intricate movements of the prostheses.
Grip positions include a ‘key grip"', which brings together thumb and forefinger, enabling an item such as a credit card to be picked up, or a key turned in a lock; a ‘power grip' to hold large or unusually-shaped objects; a ‘precision grip' for fine-tuned finger-control tasks such as picking up very small objects; an ‘index point', which extends just one finger and can be used to operate a keyboard or an ATM machine; and a 'thumb park', which folds the thumb to the side of the extended hand to allow the person wearing the prosthesis to put on a shirt, for example.