Chronic traumatic encephalopathy in contact sports: A systematic review of all reported pathological cases

© 2015 Maroon et al. Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with head trauma. Although initially believed to affect only boxers, the at-risk population has expanded to encompass a much wider demographic, including American football players, hockey players, wrestlers, and military veterans. This expansion has garnered considerable media attention and public concern for the potential neurodegenerative effects of head trauma. The main aim of this systematic review is to give a complete overview of the common findings and risk factors for CTE as well as the status quo regarding the incidence and prevalence of CTE. This systematic review was performed using PubMed and MEDLINE and includes all neuropathologically confirmed cases of CTE in the medical literature to date, from the first published case in 1954 to August 1, 2013 (n = 153). The demographics, including the primary source of mTBI (mild Traumatic Brain Injury), age and cause of death, ApoE genotype, and history of substance abuse, when listed, were obtained from each case report. The demographics of American football players found to have CTE are also presented separately in order to highlight the most prevalent group of CTE cases reported in recent years. These 153 case reports of CTE represent the largest collection to date. We found that a history of mTBI was the only risk factor consistently associated with CTE. In addition, we found no relationships between CTE and age of death or abnormal ApoE allele. Suicide and the presence of premorbid dementia was not strongly associated with CTE. We conclude that the incidence of CTE remains unknown due to the lack of large, longitudinal studies. Furthermore, the neuropathological and clinical findings related to CTE overlap with many common neurodegenerative diseases. Our review reveals significant limitations of the current CTE case reporting and questions the widespread existence of CTE in contact sports

Negative Interpretation Bias and the Experience of Pain in Adolescents

Negative interpretation bias, the tendency to appraise ambiguous situations in a negative or threatening way, has been suggested to be important for the development of adult chronic pain. This is the first study to examine the role of a negative interpretation bias in adolescent pain. We first developed and piloted a novel task that measures the tendency for adolescents to interpret ambiguous situations as indicative of pain and bodily threat. Using this task in a separate community sample of adolescents (N=115), we then found that adolescents who catastrophize about pain, as well as those who reported more pain issues in the preceding three months, were more likely to endorse negative interpretations, and less likely to endorse benign interpretations, of ambiguous situations. This interpretation pattern was not, however, specific for situations regarding pain and bodily threat, but generalized across social situations as well. We also found that a negative interpretation bias, specifically in ambiguous situations that could indicate pain and bodily threat, mediated the association between pain catastrophizing and recent pain experiences. Findings may support one potential cognitive mechanism explaining why adolescents who catastrophize about pain often report more pain. Perspective This article presents a new adolescent measure of interpretation bias. We found that the tendency to interpret ambiguous situations as indicative of pain and bodily threat may be one potential cognitive mechanism explaining why adolescents who catastrophize about pain report more pain, thus indicating a potential novel intervention target.</p

Clinical symptoms of CTE and other neurodegenerative conditions.

<p>Clinical symptoms of CTE and other neurodegenerative conditions.</p

Clinical symptoms of CTE and other neurodegenerative conditions.

<p>Clinical symptoms of CTE and other neurodegenerative conditions.</p

Results of univariate and multivariate models of survival analysis, predicting the onset of panic attacks with standardized YSR scores and adjusted for gender and SES.

*<p>p<.05 **p<.01 ***p<.0001.</p><p>YSR = Youth Self-Report; SES = Socio-economic status; CI = confidence interval;</p>1<p>part of the Externalizing scale; ² part of the Internalizing scale; ^a the eight subscales were entered into one multivariate model, and the subscales <i>Externalizing</i> and <i>Internalizing</i> were entered into a separate multivariate model.</p

History of substance (ab)use by primary TBI exposure groups.

<p>History of substance (ab)use by primary TBI exposure groups.</p

ApoE genotype breakdown in CTE diagnosed subjects.

<p>ApoE genotype breakdown in CTE diagnosed subjects.</p

History of substance (ab)use in CTE diagnosed subjects.

<p>History of substance (ab)use in CTE diagnosed subjects.</p