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Background: A 2021 National Institute for Neurological Disorders and Stroke (NINDS) consensus panel proposed a set of clinical diagnostic criteria for traumatic encephalopathy syndrome (TES) and determined provisional levels of certainty for chronic traumatic encephalopathy (CTE) pathology based on neuropathological evidence. The panel suggested the criteria needed to be validated by clinical studies of living populations exposed to repetitive head impacts (RHIs).Hypothesis: As the consensus criteria were developed solely from neuropathologically diagnosed cases of CTE, we hypothesized that they may not be readily applicable to the clinical impressions developed from the histories and examination findings of living patients whose neuropathology was unknown.Study Design: We applied the consensus criteria to 4 groups of living retired contact sports athletes collected from previously published articles in the medical literature.Level of Evidence: Level 4.Methods: Clinical evidence from 4 groups of living retired athletes (boxers and American football players) with extensive RHI exposure was available. We used the NINDS consensus criteria to determine for each athlete whether or not they met the criteria for TES. For those who met the criteria, we determined their provisional level of certainty for CTE pathology.Results: Among all 80 subjects, the prevalence of TES was 21.3% (17 of 80), the prevalence of possible CTE was 12.5% (10 of 80), and the prevalence of probable CTE was 2.5% (2 of 80). Among the 45 retired football players, the prevalence of TES was 24.4% (11 of 45) and the prevalence of possible CTE was 17.7% (8 of 45). None of the retired football players met the criteria for probable CTE. Among the 35 total retired boxers (from all 3 groups), the prevalence of TES was 17.1% (6 of 35), the prevalence of possible CTE was 5.7% (2 of 35), and the prevalence of probable CTE was 5.7% (2 of 35).Conclusion: Applying the NINDS consensus criteria to this historical cohort of living retired athletes with extensive RHI exposure resulted in a relatively low prevalence of TES and possible/probable certainties of CTE pathology, which might suggest limitations on the sensitivity of the NINDS criteria.Clinical Relevance: Physicians are often asked by retired contact sports athletes and their families to determine if their clinical picture is related to TES and/or CTE. Physicians may turn to the NINDS consensus criteria for guidance in making such determinations. The data presented here may assist physicians in evaluating the reliability and validity of using the consensus criteria in living subjects.

Background: Structural brain changes, potentially resulting from repetitive brain trauma (RBT), have been correlated with neurocognitive decline and increased symptom reporting in retired athletes.Hypothesis: In a cohort of retired National Football League (NFL) players, the relationships between 3 neuroimaging parameters, neuropsychological testing, and symptom scores will be significantly correlated.Study Design: Cross-sectional study.Level of Evidence: Level 3.Methods: Comprehensive magnetic resonance imaging was performed in 45 retired NFL players. Three neuroanatomical parameters were assessed by board-certified radiologists blinded to the purpose of the study: (1) the absence or presence of small or large cavum septum pellucidum, (2) a global mean score of fractional anisotropy (FA), and (3) the presence or absence of microhemorrhages. The subjects underwent a battery of 9 paper-and-pencil neuropsychological tests, a computerized neurocognitive test, and multiple symptom and depression scales. The associations among the neuroimaging results with these outcome measures were assessed utilizing Pearson, Spearman rank, and point-biserial correlations.Results: The 45 subjects (mean age, 46.7 ± 9.1 years) reported a mean 6.9 (±6.2) concussions and 13.0 (±7.9) “dings” in the NFL. Ten (22%) did not have a cavum septum pellucidum, while 32 (71%) had a small and 3 (7%) had a large one. Four (9%) had microhemorrhages. Global FA mean was 0.459 (±0.035). The majority (50.8%) of correlations among the neuroimaging parameters and neurocognitive/symptom scores fell below the threshold of “small” effect size (r< 0.10). The remaining (49.2%) correlations were between “small” and “medium” effect sizes (0.1 < r< 0.3). However, all correlations were statistically nonsignificant.Conclusion: There were minimal and statistically nonsignificant correlations among the neuroimaging, neurocognitive, and symptom scores examined in this cohort of NFL retirees.Clinical Relevance: Associating the severity of structural brain changes to neurocognitive performance and symptom burden after RBT is complex may involve other moderating variables or biomarkers, and demands further study.

Background: Concussion in the National Football League (NFL) remains an important issue. An initial description of the injury epidemiology involved 6 years from 1996 to 2001.Hypothesis: The increased attention to concussions may have resulted in team physicians being more conservative in treating players in recent years.Study Design: Two consecutive 6-year periods (1996-2001 and 2002-2007) were compared to determine changes in the circumstances associated with the injury, the patterns of signs and symptoms, and the players’ time loss from participation in the NFL.Methods: During 2002-2007, concussions were recorded by NFL team physicians and athletic trainers using the same standardized reporting form used from 1996 to 2001. Player position, type of play, concussion signs and symptoms, loss of consciousness, and medical action taken were recorded.Results: There were 0.38 documented concussions per NFL game in 2002-2007—7.6% lower than the 0.42 in the earlier period (1996-2001). The injury rate was lower in quarterbacks and wide receivers but significantly higher in tight ends during the second 6 years. The most frequent symptoms were headaches and dizziness; the most common signs were problems with information processing and immediate recall. During 2002-2007, a significantly lower fraction of concussed players returned to the same game, and more were removed from play. Most concussed players (83.5%) returned to play in < 7 days; the percentage decreased to 57.4% with loss of consciousness. The number of players returning in < 7 days was 8% lower during 2002-2007 and 25% lower for those with loss of consciousness.Conclusion: The most recent 6 years of NFL concussion data show a remarkable similarity to the earlier period. However, there was a significant decrease in the percentage of players returning to the same game, and players were held out of play longer.Clinical Relevance: There was a more conservative management of concussion in NFL players from 2002 to 2007 even though the clinical signs and symptoms remained similar to the earlier 6-year period.

Eighteen former and active boxers underwent neurological examination, EEG, computed tomographic scan of the brain, and neuropsychological testing. Eighty-seven percent of the professional boxers had definite evidence of brain damage. All the boxers had abnormal results on at least one of the neuropsychological tests. Brain damage is a frequent result of a career in professional boxing.(JAMA 1984;251:2663-2667)

ObjectiveTo assess interrelationships among neuroimaging findings with neurocognitive test performance and symptom endorsement in a cohort of retired professional (NFL) football players.DesignProspective cohort study.SettingNeurology clinic.ParticipantsForty-five retired NFL players.InterventionMRI scan assessment of cavum septum pellucidi, global mean score of Fractional Anisotropy (FA), and microhemorrhages.Outcome measuresNine neuropsychological tests and multiple symptom and depression scores. Associations among the three independent neuroimaging results with these outcome measures were assessed utilising Pearson’s, Spearman’s Rank, and Point-Biserial Correlations.ResultsThe retirees reported an average of 6.9 (±6.2) concussions and 13.0 (±7.9) sport-related “dings” in the NFL. Assessment of cavum septum pellucidum yielded a negative finding in 10 subjects (22%), while 32 (71%) had a small, and 3 (7%) had a large one. Four (9%) of the subjects had microhemorrhages present and average FA mean was 0.459 (±0.035). Number of sport-related “dings” was correlated with an increased risk of microhemorrhages (r=0.305, p=0.042). The majority (50.8%) of the correlations obtained among the three neuroimaging parameters and the neurocognitive/symptom scores were below the threshold of a “small” effect size (r<0.10). The remaining (49.2%) correlations fell somewhere between “small” and “medium” effect sizes (0.1< r<0.3). However, all correlations were statistically non-significant.ConclusionsThe current results demonstrate minimal and statistically non-significant correlations among neuroimaging, neurocognitive, and symptom scores examined in a cohort of NFL retirees. While an often-accepted paradigm, certain neuroimaging findings may not relate consistently and directly with neurocognitive test performance and clinical symptom burden.Competing interestsNone.GS Solomon receives consulting fees from the Tennessee Titans (NFL), the Nashville Predators (NHL), and the athletic departments of several universities; all fees paid to institution. In addition he is a member of the ImPACT Scientific Advisory Board and receives reimbursement for expenses to board meetingsAK Sills is a consulting physician to the Nashville Predators (uncompensated) and also serves as an unaffiliated neurotrauma consultant for the NFLExaminations of the NFL retirees were sponsored by the National Football League (NFL) and coordinated with the NFL Players Association (NFLPA). IR Casson served as a member of the NFL MTBI Committee from 1994-2009 and as a co-chair from 2007-2009. He has done consulting for law firms and insurance companies.