What phantom limbs and mirrors teach us about the brain

 
An amputee doing mirror therapy

In a lab in southern California scientists are curing the previously incurable with little more than a mirror, and changing our understanding of the brain in the process.

In mid-November the team at the University of California San Diego (UCSD) announced the results of a small pilot study which suggests that a simple mind trick involving mirrors can help ease the pain of osteoarthritis, a condition that affects one in 10 people.

That study is in its very early stages, but since the mid-1990s neuroscientist Vilyanur S Ramachandran, who heads the team, has been extolling the benefits of mirrors for all manner of diseases and syndromes, from stroke to the mind-boggling medical phenomenon of the phantom limb.

Ramachandran's 20-year association with the mirror, and phantom limbs, has driven him to the forefront of experimental neuroscience.

How the mirror works

A diagram of mirror therapy

The phantom (or arthritic) hand is placed behind the mirror. When the patient looks into the mirror he feels the reflection of the real hand superimposed on the phantom. He then tries to move both hands.

Many patients report they feel the phantom mimicking the movement of the real hand.

When the real hand opens its fingers, it looks as though the phantom has opened, and pain is relieved. By doing this repeatedly some patients find the phantom disappears. Providing a visual substitute for the phantom limb effectively "amputates" it.

The syndrome occurs in at least 90% of amputees - in two-thirds of those it manifests as an insatiable itch in the missing limb, many feel extreme discomfort or even chronic pain.

In most cases, pain-killers and surgical treatment have no effect.

Ramachandran's first phantom limb patient - who he calls Victor - lost his arm crossing the Mexican border into the US. He had an itch in his missing hand.

When Ramachandran prodded him in the left cheek with a cotton bud, Victor claimed he felt it in his missing left thumb - when he touched his upper lip, Victor though he was prodding his index finger.

The neurons that detect sensation in the missing hand, at a loss for anything to do, had somehow started detecting sensation in the face.

In this case there was a simple and effective treatment for the itch - scratch the face. But to Ramachandran it also had theoretical implications. It appeared to demonstrate the plasticity of brain modules - their ability to adapt to each other and their environment.

This was a radical idea as the established notion at the time was that the brain is made up of independent modules, insulated from each other and hardwired to a specific function. The notion of plasticity was something only a small group of scientists were considering.

The 'mirror neuron'

In 1994, Ramachandran proved the theory by mapping the brain activity of a group of amputees. Using a magnetic scanner he showed that neuron activity was indeed migrating from the hand area to the face. It was a ground-breaking study.

But he believed much more could be gleaned from studying phantom limbs.

What do you see?

A  test for synaesthesia

Since 1999 Ramachandran has been exploring the connections between brain modules through a condition called synaesthesia.

Synaesthetes experience a blending of their sensations - they taste letters, hear shapes or see numbers as colours. It affects 2-4% of people, is hereditary and eight times more common among artists and creative people.

Ramachandran suggests that synaesthetes have a higher number of connections between modules in the brain that process sensations such as colour and sound. He believes the condition holds clues to unravelling the mysteries of human capacity for language, creativity and abstract thought.

Do you have synaesthesia? Try and pick out the twos in this sea of fives. Number-colour synaesthetes will see the twos pop out while normal people have to look at each figure individually to tell them apart.

In the mid-1990s he followed the work of Italian scientist Giacomo Rizzolatti, who discovered an entirely new type of neuron that he called the mirror neuron.

Rizzolatti observed that certain neurons in the brain of a macaque monkey fired when the monkey reached out and when it watched another monkey reach out. Mirror neurons were later discovered in humans too.

Ramachandran began to apply this finding to his work with phantom limbs. If mirror neurons fired when an individual watched someone moving a limb, he conjectured, then visual perception might play an important role in creating the sensation of movement.

His next subject, Jimmy, felt that his phantom hand was always agonisingly clenched, with his phantom fingernails digging into his missing hand.

Ramachandran put a mirror between Jimmy's arms and asked him to move both his phantom and healthy limb simultaneously, while looking at the reflection of the healthy limb - effectively fooling Jimmy's brain into thinking his phantom was moving in a normal way.

Jimmy felt his clenched fist release almost immediately.

"This is because you are creating intense sensory conflict - the vision is telling you the limb is moving," Ramachandran explains.

"One way the brain deals with conflict is to say, 'To hell with it! There is no arm,' and the arm disappears.

"I tell my medical colleagues that it is the first example in the history of medicine of successful amputation of a phantom limb."

He called the treatment Mirror Visual Feedback therapy or MVF. But it wasn't until much later that MVF was properly acknowledged by clinicians.

Empathy

In 2007, an army medic in the US Dr Jack Tsao, performed a controlled test on 22 amputees with remarkable results. All those using the mirror reported a reduction in pain over four weeks, those using a control reported no result or increased pain.

At the UK army's rehabilitation centre, Hedley Court, mirror therapy has also been used for the past four years to help amputee soldiers to manage phantom pain.

Mirrors and landmines

Thiet Nguyen Xuan

Thiet Nguyen Xuan from Vietnam was hunting for scrap metal on a beach in September when a landmine exploded, blowing off both of his legs and two fingers from his left hand.

Since the accident, he has felt a burning sensation in his missing fingers. The End the Pain project has provided him with a mirror and training on how to use it. During the training he reported instant relief in his phantom fingers. Over the next two months the project will monitor his progress.

End the Pain hopes to extend mirror therapy to the estimated 300,000 amputees in Vietnam.

"Prosthesis-wearing is key," says army physiotherapist Major Pete LeFeuvre. Those who wait longer for a fake limb seem to suffer more from phantom pain. This suggests it is the visual feedback of seeing an arm rather than the feedback from nerves within it that stops the brain getting confused.

In Vietnam, a project called End the Pain has been running for the past three years to spread the therapy among victims of landmines and leprosy sufferers. It has reached over 100 medical practitioners so far and has also extended the project to amputees in Cambodia and Rwanda.

The simple therapy has proven useful with other syndromes that have perplexed doctors such as Complex Regional Pain Syndrome, a term for unexplained pain. And at the Royal National Hospital for Rheumatic Diseases in the UK, an associate of Ramachandran, Professor Candy McCabe is testing the use of mirrors with acute stroke victims.

Though it is in its very early stages, the experiment into arthritis at UCSD could provide the broadest use of mirror therapy yet.

Much of Ramachandran's work since developing mirror therapy has focused on mirror neurons. He believes these neurons help us understand not only what is happening to our own body, but also to others. They are the basis of empathy, he suggests, our ability to feel what others feel.

In 2009 he used the phantom limb again to provide evidence for this theory, showing that sufferers could experience relief from phantom pain merely by watching someone else massaging or flexing their own hand.

While others spend million on machines with complicated acronyms, the beauty of Ramachandran's work is that he uses ordinary items such as mirrors, pens and paper.

"The hi-tech stuff is very important but it lacks the aesthetic appeal of the other stuff," he says.

"It has the slightly boring, banal quality to it."

Find out more about VS Ramachandran's work on Exchanges at the Frontier from the BBC World Service in association with the Wellcome Collection. Listen to the programme here.

 

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  • rate this
    0

    Comment number 19.

    @ 14 You report experiencing an effect; why do you feel that others could not be experiencing a different effect? I remember in a psychology class in the late 70s doing experiments with mirrors, a small proportion of the class experienced some confusion when viewing their right arm mirrored and being asked to move their left arm that was hidden. There could be an effect that is valuable for some.

  • rate this
    -2

    Comment number 18.

    It is placebo and placebo does work. It is the brain that feels pain or rather interprets the sensory neurone impulses as pain. "It is the physician's role to amuse the patient whilst the body heals itself"

  • rate this
    +1

    Comment number 17.

    I saw the twos before the 5s, the 5s look like backward 2s, they took slightly longer to decode, I guess popped out is a good description but I am aware i have synaesthesia. Days of the week have individual colours, textures and shapes, many words provoke taste or smell, some smells and tastes provoke words or unrelated mental images. I often see concepts or systems as abstract 3D shapes.

  • rate this
    0

    Comment number 16.

    I saw a documentary of this sort of thing a while back. One bit involved hitting a phantom third hand with a hammer. It seemed that the brain was quite happy to accept the presence of a third arm pretty much instantly. Weird stuff, but fascinating.

  • rate this
    +2

    Comment number 15.

    @12.whowrotethis

    This isn't placebo. A placebo would have psychological effects through false belief, the patient in this case knows exactly what's going on.

  • rate this
    -5

    Comment number 14.

    I read Ramachandran's book "Phantoms in the brain" and watched his TED talk. I am of the opinion that he is a charlatan. I am an above knee amputee, and did the mirror trick and ... if anything it made the pain worse AND it was emotionally exhausting (seeing my leg again). I don't think he has designed and executed any meaningful experiments, and his conclusions far outweigh the evidence

  • rate this
    +2

    Comment number 13.

    Like LizzieBee, my first thought at the synethesia image was 'Mix of 5s and 2s' - not sure what that means.

    Always fascinated by brain & behaviour. I had a stroke 4 years ago and since then cannot write longhand, but retained the ability to touch-type - about all my right hand is good for these days.

  • rate this
    -10

    Comment number 12.

    This is called placebo, the bodies innate ability to heal itself when given the components to do so. Western science prefers to call it sham medicine as it does not involve any active pharmacological drugs. Clearly can't work then, oops!

  • rate this
    +6

    Comment number 11.

    30 years ago I wsa involved in an RTA. I lost the use of my right arm. I've been in pain (phantom) ever since. It is a life changing event. A 'cure' for phantom pain would similarly be life changing. Chronic pain needs a lot of energy to manage (drugs don't work long term). I'd volunteer for any project working to relieve phantom pain - including brain surgery. I hope mirror therapy works for me.

  • rate this
    +1

    Comment number 10.

    9 Lynda2011

    On House the medicine is accurate & is taken from real unusual cases published in medical journals. Guessing the odd clinic cases are passed on by chatty doctors.

    Wonder if after the episode first aired some amputees tried the mirror therapy on their own and got the relief they needed.

  • rate this
    +1

    Comment number 9.

    Glad to see it is a real therapy. I first saw it done on the TV show House last year. I thought it might be just a TV show pretend therapu\y - it seemed too easy to be real.

  • rate this
    -10

    Comment number 8.

    I am facinated by brain plasticity. To me it seems God has given us a tool to create a good reality, and makes huge sense of the bibles statement: "Be renewed by the transformation of your mind".

    Research suggests that our will can control the electro-chemistry that connect synapses and so "learn" the good/moral/effective behaviours Jesus taught. This makes "faith" relevant to everyone again.

  • rate this
    +4

    Comment number 7.

    It's good to see this work being recognised and practised across the world. I can confirm that the name of Dr Ramachandran is recognised by many in the NHS as the originator of this therapy.

    The work of ETTP is also inspiring, especially because the equipment needed is not over-priced. The previous ad I read for mirror boxes had a starting price in excess of £100!

  • rate this
    +1

    Comment number 6.

    Any treatment for pain which avoids heavy and increasing doses of opiods is good news. Both the brain and nervous system have the ability corrupt, and quickly, and also to mutate. The reality is most work in this area is unsuccessful and any therapy that helps is valuable.

  • rate this
    +5

    Comment number 5.

    Regarding the 2's and 5's puzzle - its not whether or not you can identify whats in the box, its how you did it (i.e. those with synaesthesia would spot it by the different colours of the numbers).

    Its a mind boggling condition in all its forms!

  • rate this
    +3

    Comment number 4.

    @mybbcname2

    The article says several times they've been working on this technique since the mid-nineties. The whole point is to promote it's wider acceptance.

    You might want to ask your local NHS clinic where they got the idea, it would be interesting if it's a direct result of this guy's work, which seems likely, given he's been doing it nearly 20 years.

  • rate this
    -5

    Comment number 3.

    I respect ALL Creative Inventions, and this is looking like , it works on 10% , so first therapy needs to be free. If it works, be sure that it will go on, if its not working for X , so X wont come back, but people who has needed result , will be back.

  • rate this
    -2

    Comment number 2.

    Hmm. I'm not entirely convinced by the 'Do you have synaesthesia?' image. Answering the title, before scrolling down, I had already said "5's, with a bunch of 2's thrown in". Unless of course this diagnosis entitles me to some benefit or tax exemption, in which case, yes, I definitely have synaesthesia!

  • rate this
    +7

    Comment number 1.

    All very good and laudable - but I see nothing here that a number of NHS Pain Clinics (including my local one in Taunton) have not been doing for years.

    Mirror box therapy is already fairly common - but as they say, any publicity is good publicity - and it would be good to see even wider acceptance and adoption of the technique.

 

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