American Academy of Neurology: Brain Shows Evidence of Injury Following Concussion after Acute Symptoms have Dissipated
There has been much debate over what happens to the brain following a concussion, much of it recently focused on concussions in sports. One side of the debate maintains that concussions, also referred to as “mild traumatic brain injuries,” involve only a very short term disruption of brain function with no damage to the brain. As discussed in previous posts, this view has been discounted by a growing body of research involving advanced imaging technologies as well as post-mortem pathological studies showing that in a minority of cases concussions can cause lasting damage to the brain as well as persistent symptoms.
On November 20, 2013 the medical journal of the American Academy of Neurology, a professional organization representing 21,000 neurologists and neuroscientists, published findings that after a “mild” concussion, brain scans using diffuse tensor imaging technology, showed grey matter abnormalities on both sides of the frontal cortex.
These abnormalities were still apparent four months after the concussion even in the majority of patients who appeared to have significantly recovered from acute memory, thinking and behavioral symptoms.
The authors of the study note that standard brain scans such as CT or MRI would not have detected these subtle changes in the brain, stating that “Unfortunately, this can lead to the common misperception that any persistent symptoms are psychological.”
The study shows that damage to the brain remains even in patients without significant persisting memory, thinking and behavioral symptoms. This has important implications about when it is truly safe to return to physical activities that could produce a second concussion, potentially further injuring an already vulnerable brain.
It is not clear what causes the persistent abnormalities in the brain. Possibilities offered by the authors are cytotoxic edema, which results from changes in where fluids are located in and around brain cells, or reactive gliosis, which is the change in glial cells’ shape in response to damage in the central nervous system.
It is significant that this study is being published by the mainstream organization representing neurologists, and therefore carries particular weight. The view that concussions are essentially benign is rapidly losing ground.