Presently concussions diagnosis is based primarily on the patient's accident history and on clinical examinations that check for symptoms like headache, dizziness and behavioral abnormalities.
There is no way of knowing from these exams who will suffer the most severe consequences and who will recover quickly. The results of the Einstein study indicates DTI scanning could provide a more objective way to diagnose concussions, determine whether brain injury has actually occurred following trauma, and possibly to predict the lasting loss of executive function. Executive function refers to the ability to make decisions, organize, set priorities and manage time.
The Einstein research involved 20 people known to have suffered concussions (18 from motor vehicle accidents and two from falls) and 20 healthy control subjects. The patients were recruited from one hospital emergency room; two of them had lost consciousness, but only for a few minutes. Both the patients and control subjects underwent conventional brain imaging with magnetic resonance (MR) and computed tomography (CT) scanning, plus a battery of neuropsychological tests to assess executive function, which is often impaired after a concussion. All concussion patients underwent brain imaging and testing within two weeks of their accidents.
Experienced reviewers who evaluated the conventional MR and CT images of patients and controls found no abnormalities in either group. However, the neuropsychological results showed that the patients performed significantly worse than the controls on tests of executive function.
Patients and controls also underwent diffusion tensor imaging (DTI), a recently developed MRI-based imaging technique that can detect subtle changes in the brain by measuring the diffusion of water in the brain's white matter. DTI revealed abnormal brain regions in 15 of the concussion patients, while no abnormal regions were found in controls. Most importantly, the presence of major areas of structural damage in concussion patients (as shown by large alterations in normal water diffusion using DTI) predicted low scores on their executive-function tests. These damaged areas were located mainly in the brain's prefrontal cortex, which is essential for normal executive function and is susceptible to injury in concussion.
Dr. Lipton notes that use of DTI could prompt doctors to begin treatment early, when it's likely to be most useful. "The problems in functioning caused by concussions often don't become evident until weeks or months after the injury, suggesting that the brain pathology may actually expand over time," he notes. "By detecting brain injury early with DTI and then initiating cognitive rehabilitation therapies for those patients, we may be able to limit the effects of concussions."
"We are really excited by these findings," indicates Craig Branch, Ph.D., a co-author of the study and director of the Gruss MRRC. "For the first time we appear to be able to identify the subtle pathology sometimes caused by concussion, providing researchers a 'pathology target' for the development of therapies to reduce or eliminate the damage identified by this novel imaging method." Dr. Lipton adds that DTI could help in evaluating the effectiveness of existing therapies for concussion.