The Relationship Between Extracellular Free-Water and Gray Matter Volume in Retired Professional Football Players With History of Mild Repetitive Head Injuries

Abstract

The goal of this work was to investigate whether there was a relationship present between extracellular free water and gray matter volumes in the brains of retired professional football players. A study done by Maier-Hein et al. was able to establish the relationship in a population of participants that presented clinical symptoms of Alzheimer’s Disease. Due to the multiple similarities between Chronic Traumatic Encephalopathy (CTE) and Alzheimer’s Disease, the relationship mentioned above was examined in this study using a population of retired professional football players at high risk for CTE. Changes in the white matter microstructure as well as general volumetric changes were observed by using MRI techniques. We did not find a correlation between gray matter volume and extracellular water in the players, suggesting that despite the similarities between CTE and Alzheimer’s Disease there are also distinct differences between the diseases. Multiple brain regions were found to be different between control and player groups providing evidence for brain alterations in retired football players. The regions that were statistically different in CTE compared with controls were then correlated against one another, and it was determined that multiple regions within the brain functioned as a network in its alterations. Lastly, it was shown that diffusivities of the white matter tracts correlated with volumes of the gray matter suggesting an interaction between white a gray matter in the brains of retired football players.