Gray Matter Matters in Mild Traumatic Brain Injury.

By the Centers for Disease Control (CDC) surveillance methods, approximately 1.5 million children each year sustain a mild traumatic brain injury (TBI), also referred to as concussion. The numbers are likely even higher because a substantial number of pediatric cases with mild TBI are not seen or evaluated in a medical setting. Until recently, mild TBI was mostly considered a relatively minor condition, especially in the context of sports-related concussion and mild TBIs that occurred in recreational and related activities. However, given mild TBI's high prevalence, it became clear that some children had lingering symptoms and changes that did not resolve over time.(1) This inspired the CDC and the NIH to fund large-scale studies to more fully examine brain changes in children who experience a mild TBI. Neuroimaging methods are the most direct way to study the potential effects of a mild TBI. In their study published in this issue, Mayer and coworkers(2) used advanced brain imaging methods to show regional changes in brain gray matter that lasted at least 4 months in children who sustained a mild TBI. Gray matter refers to the part of the brain that contains brain cells.