Robot help for victims

Dr Angus McMorland, left, Professor Thor Besier, right, with student Hiroharu Arima. Photo / Nick Reed

Scientists are developing high-tech help for stroke patients.

Stroke sufferers could soon have their movements aided by a high-tech robotic exoskeleton being developed with the help of New Zealand researchers.

It is hoped the device, which is in the early stages of development, will be able to react to the slightest movement of the wearer's limbs, enabling stroke patients to regain a much fuller range of functions.

Dr Angus McMorland, of Auckland University's Department of Exercise Sciences, and associate professor Thor Besier, of the Auckland Bioengineering Institute, have been creating sensors to measure the muscle activity of stroke patients, using the data to "infer their intended movement".

The data will then be relayed to the exoskeletal robot, built by Professor Minoru Hashimoto and his team at Japan's Shinshu University.

The robot is called Curara, Japanese for Clara - a character in the children's book Heidi who uses a wheelchair.

It has a powerful motor at each knee and hip, which drive braces around the joint.

They have also built an arm exoskeleton, which replicates the complex shoulder muscle.

McMorland said that as well as enabling users to perform everyday tasks, being strapped into an exoskeleton would be beneficial for rehabilitation and help stroke patients regain some natural movement.

There was a risk that the technology may misinterpret the wearer's intention, "but as part of the system you would build in safety checks and hopefully it would also correct those movements as you go 'actually I don't want to go that way'."

McMorland said the technology may eventually allow the exoskeleton to be driven by the signals of the user's brain, potentially giving people unable to move a chance to walk again.

"In those extreme cases where you can't tap into muscle activity and movement then we could still drive systems like this. The challenge becomes interpreting the brain signals, but we're working on that, too. The technology is quite expensive but part of our goal is to develop this as a technology that lots of people can use. I see this as becoming something we would expect to see people wearing one day."

A stroke occurs when a clot blocks the flow of blood to the brain, or when a blood vessel bleeds into the brain.

Cells in the affected part of the brain start to die and cease to function. This can affect a person's ability to walk, talk, eat, see, read, socialise or do things they were able to do before the stroke.

According to the Stroke Foundation of New Zealand, each year about 9000 Kiwis have a stroke. Although they often happen to older people, a quarter occur in people of working age or younger, even children and babies.

The organisation says the number of strokes could be halved if the recommended actions to reduce stroke risks were taken.

Reduce your risk of stroke

• Check blood pressure regularly

• Don't smoke

• Reduce your salt intake

• Be physically active for at least 30 minutes on most days of the week

• Maintain a healthy weight

• Limit your alcohol intake

• Check your cholesterol

Source: Stroke Foundation of New Zealand