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Until recently, it took hours to reliably test brain function in coma patients. Now, the Halifax consciousness scanner tests five key areas of brain function related to sensation, perception, attention, memory and language — in less than five minutes.
In the 2007 movie The Diving Bell and the Butterfly, a man paralyzed by a stroke is able to communicate only by blinking his left eyelid. When injury or disease leaves someone unable to speak or move, they can end up quite literally “locked” into their bodies — conscious but with no way to tell the outside world that they’re still there.
A car accident in 1998 placed Arnie Hake, a young Nova Scotian, into a coma that his doctors thought was vegetative. But his mom, after a daily vigil at his bedside, felt strongly that Arnie was still “there” — that is, “aware.”
When she persuaded Dr. Ryan D’Arcy, an NRC neuroscientist, and his colleagues to test Arnie in 2001, Arnie’s response to experimental electroencephalograph (EEG) tests showed that he was indeed aware. However, his body was unable to communicate this. Arnie died of complications shortly after, but that episode and others like it stayed with Dr. D’Arcy.
All too often, diagnosing someone whose brain has been hurt — from a banged head in a hockey game to a patient in a coma — is a guessing game. 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 inspired by cases like Arnie Hake’s, neuroscientists and engineers at NRC have developed the Halifax consciousness scanner (HCS) — an electronic device that will ultimately pack an (EEG) and highly specialized testing software into something the size of a smart phone. Most importantly, with the push of a button, an untrained person can reliably perform a complex battery of neurological tests on a patient in less than five minutes.
Glasgow coma scale
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,” says Dr. D’Arcy.
“We’ve known we could do this for the better part of 15 years,” he adds. “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, critical care units. We had to find a way to get it out into the world.”
Front line testing
Dr. Lauren Sculthorpe, an NRC neuroscientist overseeing the device’s development, says the HCS will place sophisticated brain function testing on the front lines — in ambulances to assess accident and stroke patients; with peewee hockey coaches to check players for concussion after they slam into the boards; or with families to test if a relative with Alzheimer’s or dementia is having a “good” day cognitively.
Dr. D’Arcy’s prototyped device, which NRC hopes to complete in 2011, is now the size of a common toaster and shrinking rapidly — with ease-of-use modelled after portable defibrillators already in many sports arenas. The device’s software “brain” effectively tests five areas of brain function related to sensation, perception, attention, memory and language — and takes only three percent 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,” says Dr. Sculthorpe. “I think the idea of being locked in your body, of not being able to show anybody that you’re there, and clinicians not being able to tell, is a nightmare for most of us to imagine.”
Halifax scanner was no accident
Canada is one of the world’s five leading countries for neuroscience research, and Halifax has among the most neuroscientists per capita of any Canadian city. The new device’s name — “Halifax consciousness scanner (HCS) — pays tribute both to the city where it was created and to its precursor, the well-regarded 30-year-old Glasgow coma scale (GCS).
NRC will spin off the fully commercialized product to partner company, Mindful Scientific, by next summer, but plans to continue developing the HCS to the stage where it will predict a patient’s likelihood of emerging from a coma. Demand for such devices is already high and growing — Dr. D’Arcy says one estimate places the U.S. market alone at around $8 billion by 2015.