Mild brain injury? That’s a misnomer
Yes, there are degrees of severity when the brain is hurt, but concussions can have life-altering repercussions
June 12, 2017
Dr. Leo da Costa (right) is studying imaging techniques that detect subtle changes in the brains of people who have had a concussion, or mild traumatic brain injury.The lethal effects of concussions sustained by former NHL player Eric Lindros weren’t understood when he played for the Philadelphia Flyers in the 1990s. Yet, the once-dominant power forward was a different person psychologically after repeated hits on the ice. In a 2011 Maclean’s article Lindros said, “You want to wake up in the morning, and you want to look at yourself and say, ‘I’ve got the perfect engine to accomplish what I need to in this game tonight.’ You are not going to look in the mirror and say, ‘Boy, I’m depressed.’”
A concussion, or mild traumatic brain injury (TBI), is a blow to the head or whiplash that disrupts normal brain function for less than 30 minutes. About 100,000 to 150,000 Canadians have a concussion annually, a number that is hard to ascertain because of under-reporting. Also complicating identification is that when people who’ve had a concussion seek care, there is usually no damage to the brain that’s visible on CT or MRI scans, which can be misleading, says Dr. Leodante da Costa, a clinician-scientist in the Hurvitz Brain Sciences Research Program at Sunnybrook Research Institute (SRI). “‘Mild’ TBI is probably a misnomer. There is a percentage of [these patients]—not all—that has ongoing problems. Some of [the problems] are quite disabling,” says da Costa, who as a neurosurgeon at Sunnybrook treats people who’ve had a brain injury, including concussion. Thinking and memory problems, anxiety and depression are some common symptoms of post-concussive syndrome.
Future coma care
A coma, from the Greek “koma,” meaning “deep sleep,” can be caused by a stroke, head trauma, diabetes, brain tumour or infection. People in a coma are given supportive care, but there are no treatments for recovery of consciousness, says Dr. Nir Lipsman, a scientist in the Hurvitz Brain Sciences Research Program at Sunnybrook Research Institute and a neurosurgeon at Sunnybrook. “It is such a complex illness,” he says. “Many structures and circuits in the brain are implicated. Where does one target?”
He hopes to answer this question as he establishes a functional neurosurgery program at Sunnybrook, where he will study the use of technologies like focused ultrasound and deep brain stimulation. “Functional neurosurgeons deal with problems that can’t necessarily be seen on an MRI or CT scan. The problem is dysfunction within different circuits in the brain,” says Lipsman.
Unlike other brain operations where surgeons remove large parts of the skull to access the brain, functional neurosurgical techniques are less invasive. “By comparison, deep brain stimulation is minimally invasive. It involves two holes in the skull and insertion of an electrode. Focused ultrasound is entirely noninvasive,” says Lipsman. These methods lend themselves to treatment of psychiatric and movement disorders precisely because doctors know which area of the brain is driving symptoms.
That’s not so in a coma, which is why Lipsman is working with experts in traumatic brain injury and neuromodulation to design clinical studies using these technologies to revive those who are minimally conscious. This is a state in which a patient exhibits signs of awareness, like responding yes or no to a question. He will first need to determine where in the brain treatment should be targeted, and says there must be a sound rationale for any procedure. There is much work to be done, but he is optimistic: “It’s not science fiction. It’s going to happen, but it’s critical it happens in a proper way.”
The disconnect between patients’ normal brain scans and their symptoms led him and his colleagues to use an imaging technique called magnetoencephalography to map the brain’s electrical activity after a concussion. This technique combines MRI with a test that measures electrical signals in the brain. In a study published in NeuroImage: Clinical, the researchers scanned the brains of young men who’d recently had a concussion, and those who had never had one. They compared brain activity patterns during a mental task. The average overall IQ scores of the two groups were comparable, but the images of the group who’d had a brain injury were different. “There was a lot of ‘noise’—more brain areas being activated to cope with the same processes than a normal volunteer. [Their brain activity] seems to be more disorganized and inefficient,” says da Costa.
That brains of concussed people appear to be more taxed during mental activity than those of their healthy peers might help explain their cognitive difficulties. He notes the findings may lead researchers to investigate why after a TBI the brain works harder to cope with a task, which could account for loss of concentration, for example.
What if one reason why the brain works differently after a concussion is due to a problem with its blood vessels? To answer this question, da Costa looked at cerebrovascular reactivity, which is how well blood vessels in the brain dilate in response to increased carbon dioxide (CO2). He used a machine that raises CO2 intake on men who’d recently had a concussion and on healthy men. He compared blood vessel dilation in the brain in both groups and found poorer reactivity correlated with the degree of mental impairment in men with mild TBI.
The technique may one day be used to spot complications from TBI and determine when people can resume playing sports or working, neither of which can be gleaned from standard imaging. His aim is to help people who often fall through the cracks. “When you see someone who looks perfect but who says they can’t work or go to school, or are having trouble at home because they can’t cope with stress, that makes it very difficult for them to adapt because they need some support, but it doesn’t look like they do,” says da Costa.
Dr. Anthony Feinstein, an associate scientist in the Hurvitz Brain Sciences Research Program at SRI, founded the TBI clinic at Sunnybrook in part to address this gap. The clinic, which had close to 800 visits in 2016, offers rehabilitation and neuropsychiatric services to every person treated at Sunnybrook for a mild-to-moderate TBI. Feinstein, who is a neuropsychiatrist, says about 90% of all TBIs are mild to moderate, and that people with these injuries generally don’t receive follow-up because there are so many of them.
He led a study comparing two screening tools for cognitive impairment: the standard Montreal Cognitive Assessment, a paper-and-pencil exam, and a computerized battery. Both evaluate working memory, information-processing speed, and how well the brain organizes and acts on information. The computerized test, however, which scores how fast one can add a series of numbers correctly, for example, was more sensitive in detecting problems. It identified deficits in more than one-half of participants with TBI who were deemed intact using the Montreal Cognitive Assessment. “You have to be quite impaired to do badly on the Montreal assessment. Here, we’re looking at subtle impairments, and we’re picking them up with the computerized battery,” says Feinstein.
The research, published in the Journal of Neuropsychiatry and Clinical Neuroscience, has had significant impact. The American Psychiatric Association flagged the study and sent it to its leadership. Requests for the electronic assessment from international colleagues led Feinstein to create a web page where the program can be downloaded by mental health professionals.
Feinstein’s commitment to mending the battered mind also led him to study how post-traumatic stress disorder (PTSD) can develop in spite of memory loss after a traumatic injury. “How can you have PTSD if you can’t remember the event that gave it to you? We wanted to explore that,” says Feinstein. He published a study in the Journal of Head Trauma Rehabilitation that showed people who had amnesia for less than one hour following a TBI experienced flashbacks of the incident and avoided thinking about the trauma—symptoms of PTSD. Feinstein also found physical injuries from the event were associated with increased risk of PTSD because they served as reminders.
He hopes the research will help practitioners anticipate the needs of people who’ve had a TBI, especially so-called “mild” TBI. “I think trauma surgeons need to know that physical symptoms in the context of a traumatic event raises the likelihood of developing PTSD. If they understand that, they’d be more open to referring people to psychiatry or psychology. It’s part of an education process.”
Da Costa’s research is supported by the GE-NFL Head Health Challenge. Feinstein’s research is supported by the Canadian Institutes of Health Research, Multiple Sclerosis Society of Canada and Progressive MS Alliance.
