Combat Sports Law

CTE is caused by repeated brain rattling. Data shows that the ‘dosage’ of cumulative brain rattling is tied to causation and severity of the disease.

This week data was published highlighting confirmed CTE in young athletes. In a word it is sobering.

The study, titled Neuropathologic and Clinical Findings in Young Contact Sport Athletes Exposed to Repetitive Head Impacts, reviewed data from athletes that died before age 30. Of the 152 contact sport athletes 41% had CTE on brain examination.

Among the contact sports played were

Football (76% had CTE)

Ice Hockey (37% had CTE)

Soccer (17% had CTE)

Wrestling (22% had CTE)

Rugby (50% had CTE)

Of 11 females who donated their brains only 1 had CTE. She was a Division I collegiate soccer player.

128 of the brain donors were amateur athletes. 35% of them had CTE. CTE does not care if you get paid for your brain rattling.

Since CTE can only be diagnosed in the dead with brain autopsy it is only ever confirmed in cases of people who choose to donate their brain to check for the disease. This likely leads to a level of selection bias. Notwithstanding this the data nonetheless shows high rates of confirmed CTE in young and even amateur athletes participating in sports with serial brain rattling.

The full abstract reads as follows:

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, and Participants  This case series analyzes findings from 152 of 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 and 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 significantly 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.

Conclusions and 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.