Mild traumatic brain injury, not so mild after all

Although mTBI affects over 1 million people each year in the United States, it is generally ignored as a major health issue. However, this "mild" form of injury induces persisting neurological and cognitive problems in many of these patients, exacting an enormous emotional and financial toll on society.

Despite the prevalence and impact of mTBI, little is known about how mTBI affects nerve cells and connections in the brain, and therefore clinical outcomes after injury. Smith and colleagues have begun to amass data from human and animal studies on mTBI at 2-4 days after injury using advanced neuroimaging techniques. They have found distinct changes throughout the white matter in the brain. Also, protein markers of brain pathology were identified after mTBI in the blood of mTBI patients.

Smith and his team propose a potential molecular mechanism to explain their findings. Specifically, they found that the stretching and disconnecting of nerve-cell axons after mTBI induces problems in the sodium channels found on the surface of neurons.

"This is not inconsequential," says Smith. "Indeed, the observation that brain pathology can be detected after a concussion calls for much more extensive efforts to prevent, diagnose, and treat mild traumatic brain injury."