Thesis (M.A.)--Boston UniversityChronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy and TDP-43 proteinopathy that has been documented in individuals with a history of repetitive mild brain trauma, such as boxers and football players. In addition to widespread deposits of hyperphosphorylated tau protein throughout the brain, there are also deposits of tau within the cerebellum of these individuals. Clinically CTE is associated with word finding difficulties, aggressive tendencies, short-term memory loss, executive dysfunction, attention and concentration loss, explosivity, paranoia, depression, impulsivity, visuo-spatial abnormalities and dementia. Interestingly, the symptoms found in boxers with advanced CTE are different from those reported in football players. Boxers with advanced CTE tend to have prominent gait and movement difficulties while these symptoms are rarely described in football players with CTE. This study set out to compare the pathology found in two different regions of the cerebellum (cerebellar tonsil and the superior cerebellum) in boxers with advanced CTE, to the cerebellar pathology found in football players with advanced CTE. These boxers and football players with
CTE were compared against age and gender matched individuals with no evidence of neurodegenerative disease. The clinical symptoms and microscopic pathology were compared between groups using conventional staining and immunostaining techniques (p62, GFAP, AT8). We further support our findings by citing studies that report cognitive and emotional functioning of the cerebellum, cerebellar deficits following mild traumatic brain injury, and differing traumatic affects on the brain following either translational or rotational forces. This study confirmed that boxers and football players with stage four CTE manifest clinical symptoms and cerebellar pathology indicative of CTE. The dentate nucleus of the cerebellum often demonstrates significant tau pathology. Additionally, we assert the possibility that the superior cerebellum shows more widespread pathology in football players with CTE, and that the cerebellar tonsil of boxers with CTE is often more heavily affected than in football players with CTE. While these studies are intriguing, further studies should be conducted to precisely define these changes by sampling additional areas of the cerebellum, and including a larger number of brains
