Heading in soccer has detrimental effects on microscopic brain tissue structure integrity
By Sylvia Dixon. This article was initially published in our Concussion Update newsletter; please consider subscribing.
A recent study presented at the Radiological Society of North America (RSNA) showed the adverse effects of heading in soccer (in other words, when a player hits the soccer ball with their head). An article in News Medical details how researchers found a significant decline in the microscopic structural integrity of brain tissue and a decline in verbal learning performance for young adult amateur soccer players who performed a high number of headers over two years. This breakthrough is critical because much of the previous research focuses on changes that soccer heading has on the brain after either a single time point or an entire professional career. (Regarding long-term effects, see this study on field position and dementia in retired soccer players.)
However, this current study examines the effects of soccer heading over a two-year period. According to the lead author, Dr. Lipton, this investigation is especially significant because soccer heading has the “potential for changes in young adulthood to confer risk for neurodegeneration and dementia later in life.”
Over a two-year period, researchers at Columbia University observed the brains of a group of 148 young adult amateur soccer players. The study involved soccer players completing assessments for learning and memory and Diffusion Tensor Imaging (DTI), an MRI imaging technique. DTI assesses the brain’s microstructure by tracking “the microscopic movement of water molecules through the tissue.” According to Dr. Lipton, the research showed that “high levels of heading over the two-year period were associated with changes in brain microstructure similar to findings seen in mild traumatic brain injuries.” Moreover, they found that high levels of heading were associated with a “decline in verbal learning performance” based on the results from the learning and memory assessments.
First, the researchers developed a questionnaire for the players to get an estimate of how often they were heading the ball. Heading exposure was categorized as low, medium, and high. Those who reported heading the ball over 1,500 times throughout the two-year period were classified as part of the high-heading group.
After collecting and analyzing results from the first study, the researchers completed a second study with a broader pool of subjects (353 amateur soccer players) and examined heading over 12 months. This time, they inspected the region between the gray and white matter in the brain. Researchers concluded that “the normally sharp gray matter-white matter interface was blunted in proportion to high repetitive head impact exposure.”
Dr. Lipton theorized that this gray matter-white matter interface and corresponding damage “may play a causal role in the adverse association between repetitive head impacts and cognitive performance.” Overall, the results of these studies are a cause for concern regarding the deleterious effects of heading in soccer.