Chronic Traumatic Encephalopathy in Football Players

Abstract

To the Editor The study of former professional football players diagnosed posthumously as having chronic traumatic encephalopathy (CTE) is the largest such study to date. 1 The criterion used to diagnose CTE is a crucial limitation that necessitates further discussion.According to 2016 guidelines, the only criterion necessary to diagnose CTE is identification of "at least one perivascular ptau [phosphorylated tau] lesion consisting of ptau aggregates … around a small blood vessel." 1,2 Would a neuropathologist diagnose Alzheimer disease with a solitary area of amyloid-β, or conclude that a patient had Lewy body disease when detecting a single Lewy body? These neurodegenerative diagnoses require specific pathologic criteria tied to well-defined clinical presentations. 3 The diagnosis of CTE requires neither. The proposed CTE diagnostic criterion maximizes sensitivity, identifying cases in which the condition may be present, at the cost of specificity.In the study, 55% of participants with severe CTE had only CTE, whereas 45% harbored copathologies that met neuropathologic criteria for other neurodegenerative diseases-30% of the sample carried concomitant neurologic diagnoses. Is it possible that other, better-described pathologic entities were the primary symptom-evoking entity rather than a single perivascular ptau aggregate? Moreover, the phenotype of mild CTE overlaps significantly with unipolar and bipolar and mood disorders, raising the question of perivascular ptau being more incidental than causal.High rates of neuropathologic findings in asymptomatic individuals have been observed. Jansen et al 4 demonstrated that cerebral amyloid-β was present in 10% to 44% of individuals aged 50 to 90 years with normal cognition. Furthermore, a direct causal relationship between football and neurodegenerative disorders has been called into question by large studies of high school football players. 5 Study of the correlation of neuropathologic findings and symptom profiles is in its infancy, especially when considering a disease without a concrete clinical symptom profile. Given these confounders, perhaps the 55% of athletes with severe CTE and no other neuropathologic findings would serve as the most appropriate group to study in a meaningful way.Repetitive traumatic brain injury (TBI) accrued through professional football may cause neurologic symptoms. However, we believe the low-specificity criterion on which the diagnosis of CTE was based in the study led to an overestimation of the prevalence of CTE. Further evidence is required before premature action is taken that jeopardizes a pastime central to US culture, youth development, and character building.

Overview of Sport-Specific Injuries

“…[99][100][101][102][103] Repetitive closed head injuries can lead to chronic traumatic encephalopathy. [104][105][106][107] Current recommendations are for a staged return to play; it is never appropriate to allow an athlete to return to play the day of injury. [108][109][110][111]…”

“…Second impact syndrome can cause even more severe damage or even death 99–103. Repetitive closed head injuries can lead to chronic traumatic encephalopathy 104–107. Current recommendations are for a staged return to play; it is never appropriate to allow an athlete to return to play the day of injury 108–111…”