New treatments for stroke

New treatments for stroke

by Jane McCredie

Every ten minutes someone has a stroke, but research into the brain's extraordinary capacity to rewire itself is offering new hope.

Published 16/04/2009
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[Image source: iStockphoto]

The new buzzword in stroke rehabilitation is 'neuroplasticity' – our growing awareness of the brain's ability to heal itself, creating new pathways to replace those injured by stroke.

It's a development that will bring new hope to thousands of Australians. There will be 60,000 strokes in this country in 2009 and 20 per cent of these will be in people aged under 55.

One in five people who have a stroke die within a month. Of those that survive, most experience some level of disability – ranging from difficulties with movement or speech, to memory and sensory problems.

Previously research has shown targeted physical exercises – for example, to strengthen an affected limb – can assist recovery, as can teaching people to work around their disability, finding new ways to complete old tasks.
Retraining the brain

But now, researchers are taking targeted exercises one step further and looking at ways to retrain the brain, as well as the body. We used to think any damage that wasn't repaired within a few months of a stroke would be permanent, but it now appears that carefully targeted exercises can help the brain to rebuild even years later.

However, while the brain can make these kinds of changes, it won't necessarily do it by itself.

"It is a little lazy – it repairs what it has to for survival and then leaves it at that," says Australian neuroscientist Krystel Huxlin, a researcher at the University of Rochester in the US. "However, if you push it, the damaged brain is capable of relearning many of the functions it has lost."

Huxlin and colleagues have achieved dramatic results in restoring sight to people whose visual cortex has been damaged. In the latest edition of the Journal of Neuroscience, the researchers reported on seven stroke patients who were effectively blind in at least part of their visual field – despite having nothing wrong with their eyes – because their injured brains were unable to process visual information.

Participants did daily exercises on a computer over several months. Every few seconds, a group of about 100 small dots would appear within a circle on the screen and move either left or right before disappearing again. The participants had to say which direction the dots were moving in, with a chime giving them immediate feedback on whether they had guessed correctly or not.

"The patients can't see the dots, but they're aware that there is something happening that they can't quite see," Huxlin explains. "They might say, 'I know that there's something there, but I can't make any sense of it'."

At the start of the study, most people typically guessed the right answer 50 per cent of the time, rising to 80 to 90 per cent after weeks or months of training. Eventually, as they became consciously aware of the dots, guesswork stopped being a factor. For several people, the improvement was so impressive that they were able to return to driving.

Perhaps the most exciting aspect of the work is that the participants, aged between their 30s and 80s, had their strokes up to 40 months before the program started, raising hope that recovery may be possible even years after the original injury.

"This is a type of brain damage that clinicians and scientists have long believed you simply can't recover from," Huxlin says. "It's devastating, and patients are usually sent home to somehow deal with it the best they can."

Vision is not the only sense being restored after stroke through the harnessing of the brain's own neuroplasticity.
Regaining touch

Melbourne researcher Professor Leeanne Carey works in the field of 'somatosensory' damage, in which people typically lose their sense of touch or awareness of parts of their own bodies. It can be a bit like having one limb permanently numb, says Carey, head of neurorehabilitation and recovery at the National Stroke Research Institute.

People may be unable to keep a grip on everyday objects and, with no sensation in one hand, may be exposed to serious burns or other injuries. One young stroke survivor, for example, tried to move a fridge on her own.

"She felt a bit of resistance, but didn't realise it was her own hand," Carey says. "She crushed her fingers."

Carey's research uses texture grids, with varying degrees of roughness, to retrain the brain to interpret this sort of sensory data. People are asked whether two grids have the same or different textures and can then check their answer by looking at the grids or feeling them with their unaffected hand.

As people's ability to interpret what their fingers are feeling improves, the differences between pads are gradually reduced. Huge improvements can be seen in a matter of weeks, Carey says.

All of this is bringing new hope to people who've had strokes.

"There is very clear evidence now for the potential for recovery even months and years after a stroke," Carey says. "We are really at the cusp – it is incredibly exciting."
Identifying stroke

While this new research is exciting it's important to remember early treatment is vital for stroke. The sooner someone gets to hospital after a stroke, the better their chances of survival and recovery.

The best way to identify whether someone is having a stroke is to remember FAST:

* Facial weakness – can the person smile?
* Arm weakness – can the person raise their arms above their head?
* Speech – can the person understand what you say or speak clearly?
* Time – call 000 immediately if you see someone with these signs.

Also certain factors can increase your risk of stroke. Some of these are beyond your control – such as age, gender and family history – but adopting the following lifestyle measures will reduce your risk:

* Not smoking
* Limiting your alcohol consumption
* Being physically active
* Maintaining a healthy weight
* Eating a low-fat diet.

GoodMorning, McKooi - THANK YOU so much sharing this VERY important article with us.
Good Day We read.....we learn ! ! ! thanx

I'm glad there is foward movement on this front. My mother was one kept regaining things for years after the stroke. I can't imagine how much better she would have done had the therapy been continued longer. The way insurance and Medicare worked was that they would only approve the therapy for a few weeks, and IF there were documentable improvements.

I think that the person who develops the means and methods for continued therapy to happen at home without direct medical supervision will be really onto something. I doubt any medical coverage is going to approve paying an ongoing therapy bill, even if in the end it could reduce their costs. I mean, look how shortsighted things are with OSA treatment, but that's another story.

Very interesting article, McKooi...thanks for posting it!