Four months after a mild concussion, brain scans show abnormalities even though symptoms have mostly disappeared, raising concerns that patients are at a greater risk of reinjury than previously thought.
Scientists observed oddities in the brain’s gray matter, in the area associated with complex tasks, reward, memory, planning and motivation, according to a study published in the journal Neurology. The finding may mean the brain is still healing and vulnerable even after symptoms fade, raising the risk that a second concussion during this period may result in a more serious injury, the authors wrote.
“Just because you feel ready, it doesn’t mean your body’s fully recovered,” Andrew Mayer, a study author and an associate professor at the Mind Research Network in Albuquerque, said in a telephone interview.
Concussion risks in sports have come under increasing scrutiny as research shows that some deaths among young football players could have been prevented if those with head injuries had been kept off the field, according to a 2011 study in the journal Pediatrics. Professional sports leagues, including the National Football League and Major League Baseball, have changed their medical protocols for treating players with head injuries in response to concussion data, and a study published in January in JAMA Neurology found abnormalities in the brains of former NFL players compared with their peers.
The research released yesterday showing the brain continues to suffer the effects of a concussion even after observable symptoms seem to have disappeared matches the experience of other physical injuries, Mayer said. During recoveries from burns or sprains, for example, patients stop feeling pain from their wounds before the body is fully healed.
The study compared 50 people who had a mild concussion with 50 healthy people who were about the same age and had about the same level of education. All the subjects were tested two weeks after the concussion patients suffered their injuries. Four months later, 26 of the concussion patients and 26 of people without the injury repeated tests and brain scans.
At two weeks, concussion patients reported more issues with memory and thinking skills as well as more headaches, dizziness, and depression compared with the group that hadn’t been injured. While the symptoms were reduced in the concussion group four months after the injury, special brain scans showed an increase of about 10 percent in abnormalities in their gray matter, compared with the noninjured people.
Mayer and his associates measured the changes using a technique called diffusion tensor imaging scans, which create 3-D images of nerves. More conventional methods such as magnetic resonance imaging or CT scans might not pick up these changes, he said.
“Unfortunately, this can lead to the common misperception that any persistent symptoms are psychological,” he said in a statement.
It’s not clear what causes the brain abnormalities, the researchers said. Possible explanations include changes in the location of fluids positioned in and around brain cells, or changes in the cells’ shape in response to damage, according to the study, which was supported by the U.S. National Institutes of Health.
The Institute of Medicine said in January it had begun an investigation into concussions related to sports. It will review risk factors, screening and diagnosis, as well as long-term consequences and treatment. The Washington-based nonprofit organization provides advice to policy makers and the public.