The long-term neuropsychiatric consequences of repeated mild traumatic brain injury, and specifically sports-related concussive and sub-concussive head impacts, to football players has been an active area of research at the lab of Martha Shenton, PhD, Director, Psychiatry Neuroimaging Laboratory, Department of Psychiatry, Brigham and Women’s Hospital. For decades, she and her colleagues have been investigating the role of brain abnormalities in schizophrenia, post-traumatic stress disorder (PTSD), traumatic brain injury (TBI), attention-deficit hyperactivity disorder (ADHD), velocardiofacial syndrome, and William’s syndrome.
In a study published online in the Journal of Neurotrauma (J Neurotrauma, 2015 Sep 25), Dr. Shenton Inga Koerte, MD, and Julie Stamm, PhD, conducted brain imaging of former National Football League (NFL) players between the ages of 40 and 65. The goal of the study was to examine the relationship between age of first exposure to repeated head injuries through tackle football and later-life corpus callosum microstructure. They found that former NFL players who started playing tackle football before the age of 12 were found to have a higher risk of altered brain development compared to those who started playing at a later age. The study is the first to demonstrate a link between early exposure to repetitive head impacts and later life structural brain changes.
To examine brain development in the players, the research team used diffusor tensor imaging (DTI), to look at the movement of water molecules along white matter tracts. They found that the research participants who started playing football before age 12 were more likely to have alterations of the white matter tracts of the corpus callosum.
“Ours was the first study to show that when you start playing football matters,” Dr. Shenton said. “There was an association between early exposure to repetitive head impacts and structural brain changes later in life.” The researchers found the bigger risk of alterations in brain development for players who played tackle football between the ages of 10 and 12, a critical window in the development of a child’s brain, than for those who waited longer to start playing the game. A separate study published in the Journal of Neurotrauma (J Neurotrauma, 2015 Sep 23) by the same group of researchers found that men who started tackle football before age 12 were more likely to struggle with fundamental cognitive function — like memory, reasoning and planning. They were also three times more likely to face “clinically-meaningful depression.”
This study was conducted as part of the Diagnosing and Evaluating Chronic Traumatic Encephalopathy using Clinical Tests (DETECT) project¹, funded by NIH. In a statement on the study, the researchers said “these abnormal neuroimaging findings are not necessarily indicative of chronic traumatic encephalopathy or CTE. While this study adds to the growing concern that exposing children to repetitive hits to the head in tackle football may have long lasting consequences, there are likely other contributing factors that contribute to overall risk for CTE.”
In addition, the Psychiatry Neuroimaging Laboratory has received funding from the Department of Defense for a positron emission tomography (PET) study to investigate the role of tau pathology in living retired National Football League players. Dr. Shenton is also studying the effects of subconcussive blows to the head in elite professional soccer players as well as university hockey players.
“All of these advanced neuroscience studies utilize tools and technologies developed in the PNL,” said Dr. Shenton. “They include a multi-tensor tractography algorithm (developed by Yogesh Rathi, PhD) to trace white matter pathways in the brain; a free-water imaging technique (developed by Ofer Pasternak, PhD), which provides information about the structure of the tissue; an algorithm to measure the geometry of white matter fibers (developed by Peter Savadjiev, PhD), and a compressed sensing-based algorithm for faster acquisition of diffusion MRI scans. Without these advances in imaging technology our neuroscience studies would not be possible.”
“Our studies speak to the importance of advances in neuroimaging technology. We now have many imaging tools available to us to improve our understanding of concussions and traumatic brain injuries and help the clinicians who treat patients,” said Dr. Shenton. “These were previously ‘invisible’ injuries, but now they are visible and we can track them and learn more about them and better help those who suffer these injuries. This to me is the ultimate importance of our work.”
Growing concern about repetitive hits to the head during sports and the short-term and long-term effects is warranted. “We are encouraged by the increased awareness of the acute and long-term consequences of repeated concussive and subconcussive head trauma as well as proposed legislation intended to protect youth and adolescent athletes,” she concluded.
¹Led by Robert Stern, PhD, professor and director of Boston University Alzheimer’s Disease and CTE Center’s Clinical Core