Tiny brain sensor, life-changing potential

Dr Sarah-Jane Guild holds up a tiny wireless brain sensor. It looks a bit like a glass electrical fuse; about the size of a paracetamol tablet, if that tablet was shaved down to a rectangle.

Guild, a senior research leader at the Auckland Bioengineering Institute, has been part of developing this world-first, Kiwi-designed medical device for 14 years. 

Human trials in 2024 and 2025 showed the device is safe. Now, she and her colleagues are a step closer to achieving the ultimate goal – getting it into the hands (or rather the heads) of patients with hydrocephalus – a potentially life-threatening condition caused by a build-up of fluid in the brain. 

In a tough research funding market, Guild was awarded $1.2 million in the latest Health Research Council round. The grant will allow her team to collect data on the impact of the sensors on clinical care and quality of life for patients.

She will also be looking at the economics of the device – the potential costs and savings for the New Zealand health system.

If everything goes well, Kiwi adults and children (most people with hydrocephalus are children) might be able to access the sensors in just a couple of years. 

Parallel steps being undertaken by Kitea Health, an Auckland Bioengineering Institute spin-out company, to secure Food and Drug Administration approval for the device in the US could see patients there getting the sensors not too long after their counterparts in New Zealand.

It’s hard to underestimate the impact this tiny piece of technology and glass could have on patients - indeed is already having in the patients taking part in the first human trial.

Guild tells the story of a two-year-old who arrived late last year at Waikato Hospital. The little girl has hydrocephalus. She also has a shunt – a tiny silicon tube which drains fluid from the brain harmlessly into the abdomen. It’s been the standard treatment for hydrocephalus for almost a century.

The problem is that these tiny tubes block easily – about 50 percent of shunts in children fail in the first two years.

When a shunt gets blocked it needs to be replaced fast, before the raised pressure causes irrevocable damage or death. The challenge for doctors is that the symptoms of a failed shunt – headaches, nausea, tiredness and irritability – could just as easily be caused by something far less dangerous.

The girl who arrived at Waikato Hospital was vomiting, but was it a stomach bug or a hydrocephalus tube failure? Doctors couldn’t tell without cutting a hole in her skull and inserting a catheter to measure the pressure in her brain – something no one wanted to do unless it was really necessary.

So for five days the family stayed at Waikato Hospital – waiting. 

On the fifth day, doctors noticed something bad was happening with the girl’s eyes – a sure sign of high brain pressure. A helicopter flew her to Auckland’s Starship where she underwent emergency surgery.

The shunt was replaced, but at the same time, one of the Kitea Health brain pressure sensors was inserted next to the shunt, making her the final child on the first human trial. 

The sensors can only be so small because they don’t have an internal power source. Instead, they are powered up wirelessly when they are needed, using an external “wand” the size of a table tennis bat. Patients keep their wand at home; when they need a brain pressure reading, they simply turn it on and place it over their (or their child's) skull above the implanted sensor.

The person with hydrocephalus, or their carer, can see whether the pressure is raised (indicating a possible shunt failure), or normal (indicating something else is likely the cause of the symptoms). 

If the Waikato child had already had a pressure sensor implanted when she arrived at hospital, it could have saved the two-year-old and her parents the extra days of sickness and worry. It could also have avoided some of the hospital costs for the additional days, and potentially the emergency flight to Auckland, Guild says. That’s a huge relief for the family - and a saving for the New Zealand health budget.

And if it had turned out the little girl had a stomach bug not a failed shunt? The brain pressure information from sensor readings taken at home could have meant not having to go to hospital at all.

Around 70 percent of the time when people turn up in the emergency room with symptoms that suggest their shunt might be failing, it’s a false alarm, Guild says. 

Having HRC funding for a 60-patient New Zealand study will allow the team to gather concrete data around the benefits for patients here, and the cost or savings for Te Whatu Ora – and the taxpayer.

“The FDA approval is important," says Guild. "We have to make our sensor commercially viable to make it clinically available. But we are also determined that New Zealand patients get the benefit from a product that was developed here and which has had support from the government and the community.”

Dr Diana Siew is a medtech innovation sector specialist heading up development of Medtech-iQ Aotearoa, a national medical devices and digital health innovation hub hosted by the University of Auckland and the Auckland Bioengineering Institute.

Siew says funding human trials and commercialisation is critical, but it’s not enough; a vibrant technology commercialisation ecosystem needs a joined-up approach – from blue skies fundamental science at one end, to support for startup companies to take their ideas to the next level.

The existence of Kitea Health and its sensor has involved science from a wide range of disciplines, some seemingly distant from the final medtech product: engineers studying wireless power for heavy industrial applications, physiologists looking at the cardiovascular system of rats, chemistry professors trying to make big gadgets tiny.

Some of the science started decades ago, and bringing everything together needed dedication, collaboration, luck – and money, Siew says.

“You need the whole gamut in terms of funding and support. Everything from MBIE Smart Ideas and the Health Research Council supporting foundation science, through early-stage translation and commercialisation, to company growth support.

“We have a good basic structure in New Zealand but all three of these areas are really important and we need to consolidate and keep building.”