Repeated mild traumatic brain injuries is not associated with volumetric differences in former high school football players

Douglas P. Terry, L. Stephen Miller

We investigated potential brain volumetric differences in a sample of former high school football players many years after these injuries. Forty community-dwelling males ages 40-65 who played high school football, but not college or professional sports, were recruited. The experimental group (n = 20) endorsed experiencing two or more mTBIs on an empirically validated mTBI assessment tool (median = 3, range = 2-15). The control group (n = 20) denied ever experiencing an mTBI. Participants completed a self-report index of current mTBI symptomatology and underwent high-resolution T1-weighted MRI scanning, which were analyzed using the Freesurfer software package. A priori regions of interest (ROIs) included total intracranial volume (ICV), total gray matter, total white matter, bilateral anterior cingulate cortex, bilateral hippocampi, and lateral ventricles. ROIs were corrected for head size using a normalization method that took ICV into account. Despite an adequate sample size and being matched on age, education, estimated premorbid IQ, current concussive symptomatology, there were no statistically significant volumetric group differences across all of the ROIs. These data suggest that multiple mTBIs from high school football may not be associated with measurable brain atrophy later in life. Accounting for the severity of injury and chronicity of sport exposure may be especially important when measuring long-term neuroanatomical differences.