Out on a Limb

Out on a Limb

The international reach of Doctor Wellgood knows no boundaries and this week, with our focus on brains, we cross the Atlantic where or North American correspondent Wellgood Phoebe has unearthed a leading edge technology story about prosthetic limbs and a guy she knows, John Downey, who is working on a project to wire a robotic hand and wrist directly back into someone’s brain.

John Downey is 24 and a graduate of Johns Hopkins University in Baltimore. ‘Hopkins’ is particularly known for its medical school – if you’ve ever watched ‘House’ that was sort of the inspiration. The Uni itself is in the world top 20 and a classic Liberal Arts college. John studied Biomechanical Engineering for his first degree and then moved to Pittsburgh where he is working on his doctorate on what can only be described as a mind-bogglingly spectacular project.

People have been losing limbs and bits of their bodies since the dawn of time. Just a bit after that people started trying to replace the missing bits with a selection of peg-legs, hooks and various other random bits of kit. Fast forward to today and we’ve started getting quite good at it – look at last summer’s Paralympics and you realise straight away that losing a limb needn’t be that much of a problem.

The biggest problem however is when you lose a hand. Lose a hand and you lose your sense of touch. Lose a hand and life becomes difficult. It needn’t become impossible as there are prosthetic hands that you can learn to control by using other muscles in your arm. It gives you limited grasp and movement, but it’s a lot better than nothing.



To date the research has been going extremely well with success measured by a significant amount of chocolate that has been eaten.  In some respects it’s incredible that the brain (a computer in its own right) can talk via another computer to an artificial limb. It’s also incredible that John’s team can produce an artificial hand that can behave in a way the brain wants it to.

But there are complications. The team chose to work with the hand and arm as the wrist is the most complicated part of the body and the wrist controls pretty much what the hand can or cannot do. The problems with the wrist are that it works in 3 different planes so the prosthetic limb needs 3 different motors. The problems with 3 different motors, when you place then very close to each other, is that they throw off an enormous amount of heat and can often crash. However John thinks that’s a mechanical problem time will solve.

But John, who mostly is responsible for the computer programme that interfaces between the subject’s brain and the hand, is faced with another and potentially much bigger problem – the brain itself. It’s fine when the brain does something once. The problem is that the brain is continually learning and the second and third time it does the same thing it wants to experiment and see if it can do it better a different way.

It all adds up to the fact that John is forever recalibrating the software to account for the brain’s input. Luckily he’s a patient man – the programme still has another four years to run.

tim robotic arm high


The team John works on however wants to go one (or perhaps three) better. They have developed a hand that works like a hand and that can be directly wired back into the brain and used as normal. It’s the holy grail of prosthetics – now they’ve developed a hand that can respond to the brains commands the next steps are to get it working in a real life subject. Then in designing a computer small enough to fit into a prosthetic arm and wrist which can then be wired it straight back into the thinking parts of the brain and they’ll have cracked it.

So no pressure! If you’ve seen the Stars Wars movie where Luke Skywalker gets his hand chopped off by is long estranged dad and has a new one fitted then you’ll know it’s doable. At least it is in Hollywood. John’s job is to turn science fiction into science fact.

The good news (and you may have seen it on the TV news even in the UK) is that it’s going well. John and the team work with a subject who is paralysed and who has agreed to have a computer wired directly into her brain. In turn the computer is wired to a state of the art prosthetic arm and hand. The subject is a brave lady who loves chocolate, which becomes her motivation and reward – if she can make the hand pick up the chocolate and bring it to her mouth she gets to eat it.

BCI jan grasps bar


The fact is that in the fullness of time John, who hails from North Carolina which isn’t exactly the biggest state in the USA, might just be at least partly responsible for changing the world of amputees for the better, for life. Like all the people DW features in its True Life Stories it’s apparent that quite ordinary young people can be involved in some truly extraordinary things.