Concussions Increase Risk of Brain Atrophy, Impaired Memory

Mike Segar / REUTERS

You're probably aware by now that concussions have been implicated in brain problems later in life. But for the first time, a study has shown a significant link between a history of concussions and structural changes in the brain associated with memory troubles.

In the study, published in the journal JAMA Neurology, former NFL players who had a history head injuries were found to be more likely to have a smaller hippocampus, a region of the brain involved in memory.

The researchers looked at 28 former football players, most in their 50s and 60s, 17 of whom had a history of concussions. Eight of these people, all but one of whom had experienced head injuries during their playing career, had mild cognitive impairment (MCI), which Mayo Clinic defines as "an intermediate stage between the expected cognitive decline of normal aging and the more serious decline of dementia." The scientists also examined 21 cognitively normal non-athletes who hadn't experienced concussions as a control group.

After giving all the participants tests of verbal memory and MRIs to look at their brains, the researchers found that the older athletes who'd experienced concussions had smaller hippocampi, seahorse-shaped brain regions involved in learning and storing long-term memories. These players also scored lower than other athletes and non-athletes on tests of verbal memory, though still within a normal range, according to the study. Patients with MCI also had smaller hippocampi than non-athletes.

Football players who hadn't suffered head injuries had the same average scores as the control participants, and didn't have smaller hippocampi.

"This is actually the first study we know of that has shown a clear relationship between a [past] history of concussion and brain structure and function later in life," says Munro Cullum, study co-author and researcher at the University of Texas Southwestern Medical Center in Dallas. "We have seen pieces of this complex puzzle, and there is much to be learned, but this is one of the first times we have brought all of these analyses together in one study."

The paper shows that at least "at a group level, having a concussion with loss of consciousness may increase the risk of developing a problem with memory and associated structural brain changes beyond what is seen with the normal aging process," Cullum adds.