There has long been a debate in medicine, and consequently one in the law, about whether a concussion caused by trauma can lead to structural brain tissue damage and functional deficits. While many recover from such injuries without lasting deficits, it is estimated that over 30 percent suffer from the traditional hallmarks of traumatic brain injury, such as personality changes, deficits in short-term memory, or deficits in executive functions involved in the ability to make decisions, organize, or plan.
As recently reported in the journal Radiology, researchers at the Albert Einstein College of Medicine have now demonstrated objectively the areas of the brain injured when concussion occurs. The study subjected patients who had sustained concussions to tradition MRI and CT scans, which routinely demonstrated that no structural injury had occurred. When neuropsychological testing showed effects upon their executive functions, however, the patients were then given a more sophisticated type of MRI scan known as diffusion tensor imaging (DTI). DTI can detect subtle changes in the brain by measuring the diffusion of water in the brain’s white matter. The DTI studies in these patients showed the presence of major areas of structural damage located mainly in the brain’s prefrontal cortex, a part of the brain essential for normal executive function. It is this area of the brain that is susceptible to injury in concussion, and such structures are involved in the cognitive processes that cause the functional deficits the patients were experiencing.
It is unfortunately the case that many people suffering mild traumatic brain injury are not properly advised about the possibility of functional deficit by either their medical or legal practioners. It is often the case that problems do not disclose themselves until a patient returns to more full function after orthopedic injuries have healed. It is when they try to reengage life at their former level of function that deficits begin to take shape. Using DTI as an adjunct to clinical evaluation will likely help identify those patients who should receive rehabilitation earlier when it is more useful to the patient.
We previously wrote about the advances DTI brings to this field, and that entry may also be of interest, January 22, 2008 entry.
Diffusion-Tensor Imaging Implicates Prefrontal Axonal Injury in Executive Function Impairment Following Very Mild Traumatic Brain Injury, Radiology