A Dunedin neuroscientist has discovered a new way to help people recover from stroke, by implanting an electrode into the undamaged side of the brain.

In a world-first, Professor John Reynolds and his team at Otago University have gone against traditional thinking, targeting the healthy side of the brain, rather than the area around the stroke, with electrical stimulation.

“Putting an electrode in the healthy side of the brain when someone has a stroke on the other side is really not a conventional thing to do,” Reynolds said.

“We are potentially putting something that could be risky on the good side.”

Studies show a third of the 9,000 people who have a stroke each year will never regain full movement.

Reynolds theorised that the healthy side of the brain was overcompensating for the damaged side, and inhibiting its recovery.

But to test his theory, he needed the help of the only man in the world with a patent for the technology – pioneering Belgian neurosurgeon Dirk de Ridder.

He had also tried to treat the damaged part of the brain, without success.

“So when John came up with this new idea to treat the healthy part in order to influence the diseased part. I thought it was a brilliant idea,” he said.

Together, they developed a novel device, and with funding from the Ageing Well National Science Challenge, were able to put it to the test.

During surgery, de Ridder places an electrode over the brain’s motor cortex, which controls movement.

A wire is tunnelled under the skin to the chest, where a stimulator is implanted – similar to a pacemaker.

“From a surgical point of view, it’s very safe. We don’t even see the brain because it is covered by the dura mater,” he said.

Two men volunteered to trial the device, including 61-year-old Paul Robertston-Linch.

Four years ago he had a stroke at work, which initially robbed him of his speech, and all movement down his right side.

Despite rehabilitation, he still couldn’t use his right arm and hand.

“I guess it fascinated me,” he said.

“I thought ‘I’ve got nothing to lose.'”

He can’t feel the stimulator at all, which is only activated by another device when he has physio.

Reynolds said the initial results are exciting.

The men couldn’t grip anything when they started, and at the end could lift at least 7kg.

More importantly, they had regained fine motor skills which can hamper stroke patients.

“The stimulator doesn’t make them better – it’s the rehabilitation. What we are trying to do is allow parts of the brain to wake up during that session and form new connections.”

For Robertston-Linch, the treatment has been life-changing.

“I couldn’t hold my toothbrush when I came here.

“Now I can hold it and get it up to my face… I can open and close the door. It’s fantastic.

“I often have dreams that my arm is all better and it’s an amazing feeling, so I hold on to those dreams.”

The Otago University team now hope to secure more funding so a bigger trial can go ahead, which they hope will lead to this technology being widely used to treat stroke patients.

Source: NZ Herald


  1. I am writing this on behalf of my wife Rita Flett who suffered two strokes in 2014. This left her with speech impairment and mobility problems down her right side. Her carotid artery is 100% blocked and remains that way. She was very interested to read about your ground breaking research into helping people with strokes and would like to volunteer to participate in your future program of trials if possible. Rita is 64 years old and lives in Auckland. We moved from the UK to New Zealand in May 2011. Please let us know if Rita could help you.

    Dr Innes Flett, B.Sc(Eng), PhD, MICE, C.Eng, CMEngNZ


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