Introduction: Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease believed to be consequence of repetitive head trauma. Although initially observed in only boxers, the at-risk population for CTE has recently expanded to encompass a much wider demographic including professional and amateur football players, hockey players, wrestlers, and military veterans exposed to concussive injuries, resulting in considerable media attention and public concern for the potential neurodegenerative effects of repetitive head trauma. This review compiles all neuropathologically confirmed cases of CTE in the medical literature to date in order to analyze our current understanding of CTE and better identify the at-risk population.
Methods: The meta-analysis literature review was performed using PubMed and MEDLINE. Search criteria included terms "chronic traumatic encephalopathy," "dementia puglistica," "repetitive mTBI.” Relevant cases reported in media sources were also included. Duplicate cases were accounted for and excluded. Etiology of mTBI, sex, military experience, age and cause of death, genotype, and history of substance abuse were evaluated.
Results: From April 27, 1954 to August 1st 2013, 153 unique and neuropathologically-confirmed cases of CTE were reported in the medical literature. These included mainly former amateur and professional boxers and football players. Only one female CTE case was identified. There was no apparent relationship between CTE and age of death or abnormal ApoE allele. Suicide and the presence of premorbid dementia was not found to be strongly associated with CTE.
Conclusions: These 153 case reports of CTE represent the largest meta-analysis collection to date. Prior mTBI was the only risk factor significantly associated with CTE. Due to CTE case reports selection bias and the lack of any randomized studies the incidence of CTE cannot be determined. Speculation by the media and prior CTE case reports cannot substantiate the incidence of CTE or any associated risk factors beyond mTBI based on this analysis.
Patient Care: This meta-analysis represents the largest cohort of neuropathologically confirmed cases of CTE reported in the medical literature to date. The analysis of this cohort will help to better understand and identify risk factors associated with CTE as well as deficits in current research.
Learning Objectives: By the conclusion of our session, participants should be able to explain the discovery and characteristics of chronic traumatic encephalopathy (CTE) as it relates to mild traumatic brain injury (mTBI); understand how various risk factors including subject’s genetics, substance abuse, age and others may influence the development of CTE; and recognize mTBI induced Immunoexcitotoxicity as a possible unifying cause of post-concussion syndrome (PCS), CTE and post-traumatic stress syndrome (PTSD).