Football is one of the most popular athletic activities in the United States. Unfortunately, football players commonly sustain head injuries during play, putting them at increased risk of neurodegenerative disorders—such as Alzheimer’s and Parkinson’s diseases—later in life. Researchers have recently determined that even players who experience multiple head acceleration events (HAE), which involve the head but are not severe enough to meet clinical criteria for a concussion diagnosis, can experience disruptions in brain function and development. Given the significant, long-term negative outcomes associated with multiple head injuries, researchers are highly motivated to protect athletes by determining the mechanisms underlying football-related brain damage.
A group of researchers in Indiana began by investigating changes in brain structure among high school football players, whose developing brains may be at increased risk for physical damage. They imaged the brains of 181 high school football players and 19 high school non-collision athletes, who served as a comparison group. The researchers used the scans to examine the students’ white matter, the brain tissue containing bundles of nerve cells that transport signals across the brain. The brain scans enabled researchers to identify areas of the brain that showed decreased volume of white matter, indicating damage to these delicate tissues.
The research team found that football players showed significantly less white matter volume than their peers who played non-collision sports. Furthermore, football players with multiple HAEs showed more extensive evidence of low-level brain injury than players who experienced fewer HAEs, indicating that multiple head injuries—even those that do not meet diagnostic criteria for concussion—cause greater accumulation of neural damage.
Although researchers are already knowledgeable about the long-term neurological consequences of football and other high-impact sports, most studies have focused on older, professional athletes. Importantly, the results of the current study indicate that white matter damage among football players may begin as early as high school, putting adolescent athletes at significant risk of neurological dysfunction later in life. For the safety of young players, coaches and clinicians are advised to treat any repetitive head-related injury or impact as a serious medical event.
Jang I, Chun IY, Brosch JR, et al. Every hit matters: White matter diffusivity changes in high school football athletes are correlated with repetitive head acceleration event exposure. NeuroImage: Clinical. (August 2019).