Study Suggests Routine Hits May Ultimately Lead to Brain Injury
Even though it’s preliminary research, a recent concussion study may have major implications for the consequences of head hits and could impact football at the fundamental level.
Despite involving a small sample of athletes, this study raises important questions about the effects of mild head injury among youths with developing brains, said lead author Jeffrey Bazarian, M.D. Tong Zhu, Ph.D. and Jianhui Zhong, Ph.D. are co-authors and collaborators of the study.
After being introduced to a “Diffusion Tensor Imaging” (DTI) scan by Dr. Zhong, Dr. Bazarian, an associate professor of emergency medicine at the University of Rochester Medical Center, wondered if DTI scans could aid in the study of concussions. A DTI is similar to an MRI but instead of relaying pictures it relays quantitative data that must be decoded and interpreted by experts.
DTI scans use magnetism to measure the movement of water molecules through the body’s tissues, including the neurons. The DTI scan can provide detailed information about axonal injury. Axons swell when injury occurs and the swelling impacts the movement of water, thus allowing scientists to make an educated guess about the extent of axonal injury by measuring the changes in flow and volume of water.
Dr. Bazarian and Dr. Zhong, a professor of imaging sciences and physics, studied DTI scans of ten local high school football players before and after their seasons. While they originally believed that their research would be meaningless if only one studied player experienced a concussion, they instead found that the result would be very useful.
During the 2006-2007 sports season, nine athletes and six people in a control group from Rochester, N.Y. volunteered to take part in the research. Only one of the nine athletes was actually diagnosed with a sports-related concussion, but six other players sustained various sub-concussive blows and showed abnormalities on their postseason DTI scans that more closely resembled the concussed brain than the normal brains in the control group.
The DTI scans showed a significant change in the white matter of the teenage player with a sports-related concussion. They also showed that among the intermediate group, the white matter changes were three times higher than the controls.
The imaging changes also strongly correlated with the number of head hits (self-reported in a diary), the symptoms experienced, and independent of cognitive test results, Dr. Bazarian said.
Based on their research, they discovered that extreme hits that lead to telltale signs of concussions (foggy vision and starry eyes) weren’t necessary to cause damage to a player’s brain. Rather, regular hits to a players head can accumulate and affect the player’s brain’s wellbeing.
“We didn’t anticipate that blows to the head that didn’t cause a concussion could cause abnormalities on the scan,” Bazarian said.
The results suggested that plays considered ‘the bedrock of game action,’ such as linemen colliding or a running back getting bumped while powering through a hole, could be adversely affecting a player’s health over time.
One advantage of this study is that it compares brain scans from the same player, preseason and postseason, whereas most studies compare the injured brain of one player to the normal brain of another player in a control group. By comparing brain scans from the same player, they are more easily able to notice subtle changes, because so much natural variation exists in each individual’s brain, said Dr. Bazarian.
Dr. Bazarian and Dr. Zhong began to wonder if what they were seeing was the type of injury that, “year-after-year could contribute to the traumatic encephalopathy that affected retired NFL players.”
Traumatic encephalopathy (TE), a degenerative brain condition, has recently been suspected as a long-term affect of concussions. Some experts believe that TE can cause depression and in more serious causes can lead to potentially suicidal behavior.
After receiving a grant from the NFL to continue his research, Dr. Bazarian began to examine the University of Rochester football team. Dr. Bazarian then outfitted ten of Rochester’s football players with special helmets designed by Riddell, which were adorned with sensors to measure each hit a player receives. The sensors, called “accelerometers,” can detect the amount of direct force an impact delivers and also measure how much the impact causes the helmet to rotate.
As part of the study, each player had a DTI scan before the beginning of the 2011 season and will have a second scan when the season ends. By combining the DTI scan with the data from the accelerometers, the researchers can determine if the number of collisions matches the degree of brain injury.
They are also interested in adding a third phase to the study where they will test whether or not the practice of ‘resting players’ if effective. To do this, they must see if the patterns of damage that they discovered will heal after an extended period of inactivity. Thus, players in the study group had to agree to abstain from contact sports for a total of six months after the season ends. After those six months, a third DTI scan will be administered and then compared to the previous scans to check for signs of healing.
Unfortunately, as a result of the three phases, the study will not begin to produce conclusive results until the end of next year. When asked about the study, Dr. Bazarian stated, “At the end of the day, I think we’re just trying to avoid dementia from happening down the line. I have three kids. I don’t want them getting hurt and having brain injury from something they love to do.”