Neurology Central

Early exposure to repetitive head impacts in tackle football linked to altered brain development

Evidence linking early exposure to tackle football and increased risk of altered brain development has recently been published in the Journal of Neurotrauma by researchers from Boston University School of Medicine (MA, USA) and Brigham and Women’s Hospital (MA, USA). The study is the first to highlight a link between exposure at a young age to repetitive head impacts and structural brain changes.

Within the study, diffusion tensor imaging was utilized to compare white matter tracts in 40 former National Football League (NFL) players between the ages of 40 and 65. All of the players also had a history of at least 6 months of cognitive problems with memory or thinking.

Individuals that participated in tackle football before the age of 12 were more likely to have alterations in the white matter tracts of the corpus callosum, which connects the two cerebral hemispheres, despite the total reported concussions between the two groups being consistent.

While only performed on a subset of tackle football players, those that moved on to compete at the professional level, this study contributes to the growing evidence that there is a ‘critical window’ of brain development, when the brain is especially susceptible to injury, between the ages of 10 and 12. Lead author Julie Stamm (University of Wisconsin, WI, USA) explained: “this development process may be disrupted by repeated head impacts in childhood possibly leading to lasting changes in brain structure”. While this study reports alterations to the corpus callosum microstructure, disrupted neurodevelopment is also associated with a greater vulnerability to the aging process.

Martha Shenton (Harvard Medical School, MA, USA) however reiterated that the results “do not confirm a cause and effect relationship, only that there is an association between younger age of first exposure to tackle football and abnormal brain imaging patterns later in life.” When discussing concerns for professional players the study’s lead author Robert Stern (Boston University) added that: “these abnormal neuroimaging findings are not necessarily indicative of chronic traumatic encephalopathy” and that “there are likely other contributing factors that contribute to overall risk for CTE.”

Source: Boston University Medical Center press release; Stramm JM, Koerte IK, Muehlmann M et al. Age at first exposure to football is associated with altered corpus callosum white matter microstructure in former professional football player. J. Neurotrauma doi:10.1089/neu.2014.3822 (Epub ahead of print).