I asked Dr. McKee how CTE was determined. In this study, a single pathologist made the diagnosis, but she let me know that an upcoming study with independent pathologic review shows "very good inter-rater reliability". In lay terms, that suggests that CTE, as seen here with characteristic phosphorylated tau deposits, is a distinct pathological entity.
Risk of CTE was higher with more years of football playing and with playing at a higher level. 110 of 111 – that's 99% - of former NFL players had CTE.
The question everyone is asking, of course: how prevalent is CTE in these athletes?
This autopsy study was not a random sample of football players. Far from it. 81% of the brain donations reviewed were the result of a family member approaching the center near the time of death. They did this precisely because there were concerning symptoms.
86% of these individuals had memory problems, 72% had dementia in their last year of life, 91% had behavioral or mood symptoms, 68% had motor symptoms. The authors, to their credit, state that this study can not impute or imply the prevalence of CTE in footballers.
beat_schrute on July 25th, 2017 at 15:53 UTC »
NYT article explains that the headline is a little sensationalized but that the findings are still significant.
*Edit - formatting
beo559 on July 25th, 2017 at 15:43 UTC »
Do we have any idea what the baseline incidence of CTE, using the same criteria used in this study, might be in the general population?
mcscreamy on July 25th, 2017 at 15:08 UTC »
Link to original article
Importance Players of American football may be at increased risk of long-term neurological conditions, particularly chronic traumatic encephalopathy (CTE).
Objective To determine the neuropathological and clinical features of deceased football players with CTE.
Design, Setting, and Participants Case series of 202 football players whose brains were donated for research. Neuropathological evaluations and retrospective telephone clinical assessments (including head trauma history) with informants were performed blinded. Online questionnaires ascertained athletic and military history.
Exposures Participation in American football at any level of play.
Main Outcomes and Measures Neuropathological diagnoses of neurodegenerative diseases, including CTE, based on defined diagnostic criteria; CTE neuropathological severity (stages I to IV or dichotomized into mild [stages I and II] and severe [stages III and IV]); informant-reported athletic history and, for players who died in 2014 or later, clinical presentation, including behavior, mood, and cognitive symptoms and dementia.
Results Among 202 deceased former football players (median age at death, 66 years [interquartile range, 47-76 years]), CTE was neuropathologically diagnosed in 177 players (87%; median age at death, 67 years [interquartile range, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]), including 0 of 2 pre–high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 National Football League (99%) players. Neuropathological severity of CTE was distributed across the highest level of play, with all 3 former high school players having mild pathology and the majority of former college (27 [56%]), semiprofessional (5 [56%]), and professional (101 [86%]) players having severe pathology. Among 27 participants with mild CTE pathology, 26 (96%) had behavioral or mood symptoms or both, 23 (85%) had cognitive symptoms, and 9 (33%) had signs of dementia. Among 84 participants with severe CTE pathology, 75 (89%) had behavioral or mood symptoms or both, 80 (95%) had cognitive symptoms, and 71 (85%) had signs of dementia.
Conclusions and Relevance In a convenience sample of deceased football players who donated their brains for research, a high proportion had neuropathological evidence of CTE, suggesting that CTE may be related to prior participation in football.