The world’s first stroke helmet study

It is hoped that the stroke helmet can be used in an ambulance to determine whether or not a stroke has been caused by a haemorrhage, so that patients can quickly be given the right treatment. 


Can a stroke helmet in an ambulance determine whether or not a stroke has been caused by a haemorrhage, enabling the right group of patients to be treated quickly and reduce the risk of serious consequences? A study currently being carried out in Gothenburg hopes so.

Christer Axelsson, a paramedic and assistant professor at the University of Borås, is coordinating the stroke helmet project (with a clinical study called AmbuStroke) on paramedic care at Sahlgrenska University Hospital. He explains that it is currently too early to say anything about the results. The current stage involves testing the equipment so that it can be CE-marked, showing that it meets the EU’s safety requirements.

“We can use the helmet to take measurements in the ambulance,” he explains. “Checks are then carried out with computed tomography and the helmet at the hospital. This data is combined to compare the correspondence between the different measurements.”

The aim is to find out the cause

A stroke can be caused by either a blood clot in the brain or a haemorrhage. In the case of a blood clot, it is extremely important that clot dispersal treatment is given quickly in order to minimise brain damage, but this treatment absolutely must not be given if the stroke is caused by a haemorrhage.

The aim of the stroke helmet is to find out in the ambulance whether the stroke has been caused by a haemorrhage, instead of waiting for computed tomography to be carried out at the hospital.

Tests on the helmet began in summer 2015 and will continue for several years, since around 500 patients must be included.

“We travel in an assessment car, which – when appropriate – accompanies ambulances on call-outs where a stroke is suspected. So far, we have rather crude instruments and guidelines for which patients should be included, but we are currently improving these.” 

The helmet is fitted with antenna

What is referred to as a stroke helmet is actually more like a head support than a helmet. However, the first prototype used a cycle helmet and the name stuck.

The ‘helmet’ is fitted with antenna that transmit microwaves similar to those in mobile phones but with lower power. The patient lies with his head in the helmet, and the antenna are folded down. They measure a distribution pattern in the brain, which is sent to a computer program where an algorithm that recognises different patterns looks for distribution patterns characteristic of a haemorrhage. If such a pattern is detected a haemorrhage can be suspected, and if so clot dispersal treatment can be given. If no such pattern is detected, it is hoped that this will be enough to rule out a haemorrhage so that the patient can receive treatment immediately.

Similar studies are being carried out elsewhere in the world, but this study has made the most progress and is the first to be carried out in an ambulance setting. Once the equipment has been CE-marked, the project will continue and its properties in treatment can be tested.

Text: Lena M Fredriksson
Foto: Håkan Hörnell / Medfield diagnostics