Until recently, it took two or three hours to reliably test brain function in coma patients − and just a handful of well-equipped neurological labs in the world could do it.
But now, neuroscientists and engineers at the Canadian National Research Council (NRC) have developed what they are calling the Halifax consciousness scanner (HCS) − an electronic device that will ultimately pack an (EEG) and highly specialised testing software into a product the size of a smart phone.
According to the researchers, an untrained person will be able to use the device to reliably perform a complex battery of neurological tests on a patient in less than five minutes.
For 30 years, doctors have inferred brain function from patients’ physical reactions, based on a checklist called the Glasgow coma scale (GCS). This checklist is useful because a clinician can administer it anywhere and it assigns an easily understood score to a patient’s condition. But its accuracy depends on a doctor’s expertise and upon patients being able to respond physically.
Nearly half the time, the GCS fails to detect the awareness of deep coma patients who are not vegetative, but who cannot respond in any way. Yet treatment choices − and patients’ odds of recovery − rely on that critical diagnosis.
’Asking for a physical response when brain damage occurs means that our ability to read that response is almost always compromised. You need a better measure and that comes from brain waves,’ said Dr Ryan D’Arcy, a neuroscientist at the NRC.
’We’ve known we could do this for the better part of 15 years,’ he added. ’We knew we had a way to help people, but we had to take something that was only accessible in a research lab and turn it into a point-of-care device that worked anywhere − homes, ambulances, arenas, emergency rooms and critical care units,’ he added.
Dr Lauren Sculthorpe, an NRC neuroscientist overseeing the device’s development, has already developed a prototype, which NRC hopes to complete this year. Presently, the device can test five areas of brain function related to sensation, perception, attention, memory and language − and takes only three per cent of the time of a lab-based EEG test.
’Ultimately, the device will be designed so that you don’t even need to know about EEGs or how to set up electrodes. The instructions will be clear and simple, so that a person who has no knowledge of EEGs can slap it on,’ said Dr Sculthorpe.
The Halifax consciousness scanner is currently being tested on brain trauma patients. Left to right: Sujoy Ghosh Hajra, Careesa Liu and Dr Lauren Sculthorpe of the NRC Institute for Biodiagnostics