RSI may be caused by confusing the brain’s electrical systems. To rewire it, your fingers need a discriminating sense of touch. So, Roger Dobson asks, anyone for a game of Braille poker?
Forget painkillers, physiotherapy and surgery – playing poker with Braille playing cards may be the way to rid ourselves of the growing plague of repetitive strain injury (RSI).
New research suggests that some forms of RSI may be a problem of the brain rather than of the hands and arms. The brain, it’s suggested, gets confused with demands for too many quick, repetitive movements characteristic of today’s computerised work, and tries to take short cuts. Researchers believe that re-educating the brain to be more discriminating, with sensory exercises such as using Braille cards or playing dominoes with the eyes closed, may be the answer.
RSI, or non-specific upper limb disorder as clinicians now prefer to call it, is a group of only partly understood conditions that have been linked to jobs as diverse as keyboard users and chicken pluckers. All have one factor in common – they involve highly repetitive hand or arm movements.
Specific conditions include nerve compression, tendonitis or inflammation of the tendons, carpal tunnel syndrome, which causes hand numbness and pain, and focal hand dystonia – involuntary movements and spasms in the hand and fingers.
All have different symptoms, from pain and stiffness to involuntary movements and cramping. Treatments range from anti- inflammatory drugs to surgery, but in many cases the only cure is a change of job.
As well as enduring chronic pain, sufferers of RSI have for years also had to put up with claims that the condition is all in the mind, a view fuelled by the drop in reported cases in Australia after the government cut compensation for victims.
One of the reasons RSI attracts such controversy is that many of the individual conditions and symptoms cannot be fully explained by doctors. Nor is it yet clear why some people get the symptoms, while others doing the same tasks do not.
Because this condition is so elusive, researchers around the world have been searching for explanations of it, as it affects an increasing number of people.
Among them is Professor Nancy Byl, from the University of California in San Francisco, who has carried out work with both animals and humans suffering from focal dystonia.
She believes that far from being an entirely physical disorder, the root cause of RSI does lie in the brain, but not perhaps in the way that critics have suggested.
The theory is that when the demands for repetitive movements come too fast, the brain does not complete the processing of one message before another arrives, and confuses the two as the same signal.
Every millisecond of the day the brain gets signals from sensors all over the surface of the body. It stores these signals along the sensory cortex, a kind of cerebral filing cabinet with a drawer for each finger, lip, leg, arm and so on.
So, for example, when a finger is required to touch a key on a keyboard, it is immediately logged on the sensory cortex in the brain and a message is sent across to the motor cortex which has a similar filing system. A neuron is then fired off to move the finger.
What Byl and her team have found is that when the sensory messages came thick and fast over a long period of time, the brain can’t handle them and like a juggler with too many balls, starts to miss some. But instead of dropping them – like the juggler – the brain groups messages together, and sees two as one.
The result is that two messages to the sensory cortex requesting two different movements will only be linked to one movement from the motor cortex. That may, for instance, trigger an unwanted movement in a finger, or a spasm in the wrist.
Such movement may over time lead to muscle pain and joint problems.
“We looked at patients with severe RSI leading to focal dystonia and we did sensory discrimination tests and we found that they had problems they didn’t know they had,” says Byl. “We think that this sensory deficit leads to problems with the sensory motor feedback and ultimately a degradation of motor performance.”
The good news that comes with Byl’s research is that it may make at least some forms of RSI more treatable.
“It is possible to modify the way the cortex works to improve motor control. We have treated 10 patients with sensory retraining exercises, and I am optimistic we are on the right track. It seems to be a learned function that can be changed with behavioural training.”
Some clinicians, however, are not so sure that RSI does have a single cause and believe that a variety of factors, including genes and personality, may be involved.
“It’s likely that it is multi-factorial,” says Dr Philip Helliwell, consultant rheumatologist and senior lecturer at Leeds University.
“You have to have a physical insult – too many movements like flipping cards or putting chocolates into boxes – but there also has to be something that predisposes you to it.
“There are plenty of theories about. One camp says it is psychological and another says it is physical, and there’s a camp in the middle which says it is interaction between physical and mental. My tent is pitched in this middle group, but leaning more towards the physical.
“There may be genetic factors that predispose you to get the pain, but whether you actually complain to your manager with that pain depends on other factors,” says Helliwell.
Handy hints
Exercises to teach your fingers how to discriminate again:
l Play dominoes with your eyes closed.
l Match a shape to an opening with eyes shut.
l With your eyes closed, put together puzzles that have a raised surface.
l Play cards using a Braille deck.
l Ask someone to draw letters and numbers on your fingers, and with eyes closed try to guess what they are writing.
l Get someone to rub different objects on your hand and try to identify them.
l Carry pairs of different shaped objects around in your pocket and try to match them.
l Make a grab bag of different shaped items and try to identify them.
l Play games requiring orientation, such as pinning the tail on a donkey blindfolded.
ENDS
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