Two individuals suffer traumatic brain injuries (TBI) with the same level of severity. Yet their recoveries are markedly different. Why?
A TBI can occur when a person experiences sudden brain trauma. Although a blow to the head is a common cause, injury to the head is not the determining feature of any brain injury. Over the years, scientists have been studying the factors that play a role in TBI recovery. Dr. Donald Stuss and his colleagues, originally at the University of Ottawa and later at the University of Toronto, have focused primarily on the impact of TBI on behaviour.
The journey for Dr. Stuss started some 30 years ago in his clinical practice. He noticed that patients who appeared to have returned to normal abilities on standardized psychological tests continued to complain of problems.
He reviewed the evidence on where brain damage was most likely to occur after TBI. He found that frontal-temporal regions of the brain were most likely to be injured, regardless of what the mechanism of brain damage was. Once he started to focus on tests particularly sensitive to these regions, the lingering problems the patients were describing were clearly evident.
The frontal lobes, which constitute some 23-33% of the entire brain, were once considered as one functional entity. However, with the help of funding from the Canadian Institutes of Health Research (CIHR), Dr. Stuss has identified at least four functional regions within the frontal lobes.
One region is important for drive and activation. Damage here results in significant slowing of behaviour. If damage occurs in another area of the frontal lobes, the patient may have notable personality changes. In still another region, decision making, planning and monitoring of behaviour may be affected. And damage in the very front, just above the eyes, can result in difficulties integrating behaviours and being self-reflective.
The implications for TBI were obvious. If TBI tends to damage the frontal lobes, and if the frontal lobes are as complex as Dr. Stuss’ research suggests, then different TBI patients will experience different syndromes depending on where the injury occurred in their brain.
Then-doctoral student Katherine Krpan, along with Dr. Stuss and Drs. Nicole Anderson and Deirdre Dawson, continued this line of research by studying coping mechanisms after TBI.
They were able to demonstrate that, independent of the severity of injury, some patients were “planners” and “avoiders” in coping with life. Planners had better executive functions (decision making and monitoring) and better emotional reactivity. The performance of the avoiders, on the other hand, was related to impaired executive function.
According to Dr. Stuss, the best clinical diagnosis and care must be based on the best science, and as our knowledge of TBI changes, care should change. His research has shown that patients are usually the best indicators of what should be studied next, and that understanding the individual patient enables the clinician to target the best treatment.
But Dr. Stuss says there is much more to discover about TBI.
“We are learning that an individual’s genetic make-up plays a role in recovery. The person’s social environment can dramatically alter the support provided to maximize recovery. What remains to be determined is how these different factors truly interact, and how one uses this information for rehabilitation and optimal recovery and social integration.”