Question: What are the neuropathological and clinical findings in a convenience sample of young, deceased, symptomatic contact sport athletes?
Findings: In this case series of 152 contact sport athletes younger than 30 years at the time of death, chronic traumatic encephalopathy (CTE) was found in 63 (41.4%), with nearly all having mild CTE (stages I and II). Neuropathologic abnormalities associated with CTE included ventricular enlargement, cavum septum pellucidum, thalamic notching, and perivascular pigment-laden macrophage deposition in the frontal white matter.
Meaning: These findings confirm that CTE and other brain pathologies can be found in young, symptomatic contact sport athletes, but the clinical correlates of these pathologic conditions are uncertain.
Importance: Young contact sport athletes may be at risk for long-term neuropathologic disorders, including chronic traumatic encephalopathy (CTE).
Objective: To characterize the neuropathologic and clinical symptoms of young brain donors who were contact sport athletes.
Design, Setting, & Participants: This case series analyzes findings from 152⁄156 brain donors younger than 30 years identified through the Understanding Neurologic Injury and Traumatic Encephalopathy (UNITE) Brain Bank who donated their brains from February 1, 2008, to September 31, 2022. Neuropathologic evaluations, retrospective telephone clinical assessments, and online questionnaires with informants were performed blinded. Data analysis was conducted between August 2021 and June 2023.
Exposures: Repetitive head impacts from contact sports.
Main Outcomes & Measures: Gross and microscopic neuropathologic assessment, including diagnosis of CTE, based on defined diagnostic criteria; and informant-reported athletic history and informant-completed scales that assess cognitive symptoms, mood disturbances, and neurobehavioral dysregulation.
Results: Among the 152 deceased contact sports participants (mean [SD] age, 22.97 [4.31] years; 141 [92.8%] male) included in the study, CTE was diagnosed in 63 (41.4%; median [IQR] age, 26 [24–27] years). Of the 63 brain donors diagnosed with CTE, 60 (95.2%) were diagnosed with mild CTE (stages I or II). Brain donors who had CTE were more likely to be older (mean difference, 3.92 years; 95% CI, 2.74–5.10 years)
Of the 63 athletes with CTE, 45 (71.4%) were men who played amateur sports, including American football, ice hockey, soccer, rugby, and wrestling; 1 woman with CTE played collegiate soccer. For those who played football, duration of playing career was substantially longer in those with vs without CTE (mean difference, 2.81 years; 95% CI, 1.15–4.48 years).
Athletes with CTE had more ventricular dilatation, cavum septum pellucidum, thalamic notching, and perivascular pigment-laden macrophages in the frontal white matter than those without CTE.
Cognitive and neurobehavioral symptoms were frequent among all brain donors. Suicide was the most common cause of death, followed by unintentional overdose; there were no differences in cause of death or clinical symptoms based on CTE status.
Conclusion & Relevance: This case series found that young brain donors exposed to repetitive head impacts were highly symptomatic regardless of CTE status, and the causes of symptoms in this sample are likely multifactorial. Future studies that include young brain donors unexposed to repetitive head impacts are needed to clarify the association among exposure, white matter and microvascular pathologic findings, CTE, and clinical symptoms.
…The 1 female player diagnosed with CTE was 28 years old at death and played soccer as a forward for 18 years, beginning at age 3 years and playing through 3 years of Division I collegiate soccer. She was diagnosed with attention-deficit/hyperactivity disorder in college and prescribed stimulants. In addition to 2 concussions without loss of consciousness playing soccer, at age 24 years, she experienced a syncopal episode and a traumatic brain injury with loss of consciousness for 3 minutes. Computed tomographic findings were unremarkable. 4 years later, she developed paranoia and suicidal thoughts. At 28 years of age, she died by suicide. Postmortem examination revealed stage I CTE, mild arteriosclerosis, moderate white matter rarefaction, and marked perivascular pigment-laden macrophages in the frontal white matter (Figure 3).