Making headway on head injuries
Making headway on head injuries
As a young neuropsychologist, Alain Ptito was troubled by the sizeable number of his patients who suffered symptoms of traumatic brain injury after scans pronounced them recovered from their concussion.
“Insurance companies would say this is a psychological problem; let’s treat it with therapy,” he recalls.
But Ptito decided to trust his patients and investigate further. He has since made a career out of exploring new methods for using structural and functional magnetic resonance imaging (MRI) to probe brain trauma.
Today he is a professor of neurology and neurosurgery at McGill University, and a medical scientist at the Research Institute of the McGill University Health Centre. As he and others have shown in the last few years, mild traumatic brain injury often doesn't show up on conventional scanners.
While severe and moderate traumatic brain injury can be seen more clearly, mild injury usually comes in the form of sheared axons, which are too subtle to pick up. Axons are the long thread-like extensions of brain cells which conduct electrical impulses from one cell to another.
“So there are interrupted connections in the brain,” says Ptito. “But axons are small and the resolution in traditional scans is not high enough to detect them.”
This means patients can be given a premature “all-clear” to return to work or the hockey rink. Yet without sufficient recovery time, they are vulnerable to further injury and continue to feel unwell: symptoms include memory and attention problems, depression, anxiety and headaches.
Even when the injury is mild, symptoms can still be severe and often have huge economic costs because people are unable to work, says Ptito.
Sometimes called “a silent epidemic,” mild traumatic brain injury affects roughly 200,000 Canadians every year but only recently have doctors and the general public begun to take it seriously.
That’s because research — including Ptito’s work — now shows not only that symptoms can be debilitating, but that repeated injury can increase a person’s risk of degenerative brain disease later in life.
Ptito points to autopsies performed on the brains of professional hockey and football players who committed suicide. The players, most of whom suffered repeated mild traumatic brain injury during their careers, were found to have the brains of 80-year-olds, even if they were in their 30s or 40s. Many also had signs of degenerative brain disease, including chronic traumatic encephalopathy (CTE), which is linked to Alzheimer’s.
Research also shows that if you have one concussion, the probability of suffering subsequent concussions is higher. While the reason for this is not clear, it probably has to do with slowed reaction times that make patients vulnerable to re-injury.
Ptito’s research into developing techniques for early diagnosis promises to help patients get the treatment they need and accurate advice about when they can return to their normal activities. With help from the Canada Foundation for Innovation, Ptito, along with researchers Reza Farivar, Robert Hess, Christopher Pack and other collaborators, has been able to buy an ultra-high-performance MRI system that can see subtle changes in brain structure and activity, including those resulting from mild injury.
The MRI system has a resolution up to 64 times greater than standard MRI machines and is one of only two such systems in the world. The other is at Massachusetts General Hospital. Canada’s machine will be installed in the level one trauma centre of Montreal General Hospital, where it will be used to diagnose patients, study the brains of varsity athletes at McGill before the season begins and after concussions, evaluate treatment and validate diagnostic blood tests.
Ptito and his team are trying to come up with blood tests that indicate a risk for degenerative disease later in life and/or a genetic predisposition to suffer more severe and prolonged symptoms. “We know two individuals can get hit with the same force and one will have chronic symptoms while the other will recuperate,” he says.
He and his team are also investigating treatments, including transcranial magnetic stimulation (TMS). It involves targeting injured regions of the brain with a magnetic field to increase blood flow. This is important because blood carries oxygen, a necessary ingredient for a functioning brain. Pilot tests with the ultra-high-performance MRI system show TMS does increase blood flow and patients report improvement.
In a separate study, Ptito is investigating whether electrically stimulating the tongue could be an effective treatment. The tongue is connected to two cranial nerves, which are in turn connected to the brain stem. He hopes to show that stimulating the tongue via electrodes stimulates the entire brain and encourages uninjured regions to take over for injured ones.
“The ultra-high-performance MRI system will help us observe the brain’s response to trauma with exceptional precision,” says Ptito. “This knowledge will allow us to develop new diagnostic tools and treatments to help thousands of Canadians who suffer head injuries every year.”