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

Abstract

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.

Cumulative Effects of Prior Concussion and Primary Sport Participation on Brain Morphometry in Collegiate Athletes: A Study From the NCAA–DoD CARE Consortium

“…Several previous studies in both retired and active athletes have reported smaller hippocampal volumes associated with more exposure or repeated concussion (16,18,22,23). Other studies, however, have reported no associations (13,19,20), while a recent study observed larger hippocampal volumes in current athletes with prior concussion relative to matched athletes without a history of prior concussion (47). The current sample's distribution of concussion history (mean of 0.44 concussions) was considerably less than other prior studies recording an association between brain morphometry and concussion history.…”

“…( 11 – 16 , 22 , 24 – 26 ). Others, however, have also failed to record such a relationship or were unable to differentiate the effects of exposure and concussion ( 18 – 20 ). One possible explanation is that subcortical regions experience more mechanical stress from head impacts relative to the cortical mantle ( 48 ).…”

“…Similarly, thalamic volumes have been inversely associated with level of exposure to contact sport in retired professional football players (17). Conversely, other studies have reported no differences in brain morphometry among former contact sport athletes with different competition level participation histories (18)(19)(20). Prior work, however, did not aim to separate the effects of exposure to contact sport from the long-term effects of concussion, did not account for other confounding factors, or focused on older adults who were typically many years removed from their most recent concussion or contact sport exposure (21).…”

Long-Term Cognitive Performance of Retired Athletes with Sport-Related Concussion: A Systematic Review and Meta-Analysis

“…After removing duplications ( n = 146), 852 records were screened through identifying the titles and abstracts, and 24 records were retrieved for full-text reviews. Finally, a total of 11 studies [28,29,30,31,32,33,34,35,36,37,38] that met the inclusive criteria were included for this meta-analysis.…”

The synergistic effect of concussions and aging in women? Disparities and perspectives on moving forward

“…Alterations in brain function and structure have also been shown in former American high school and college football players with cognitive deficits and depression, although these changes were not related to concussion history [ 44 ]. However, recent work from Terry and colleagues did not find a relationship between mild TBIs in high school football players and brain atrophy in later life [ 45 ].…”