Marshall C. Freeman, MD, FAHS
The story of NFL player Aaron Hernandez is tragic. A successful tight end drafted in 2010 by the New England Patriots, Hernandez signed a five-year $40 million dollar contract extension in 2012 that would have run through 2018. This was one of the most lucrative contracts ever negotiated for a tight end, including an astounding $12.5 million signing bonus. Hernandez would have ultimately become a two-time winning Super Bowl champion with the Patriots in 2014 and 2016. Unfortunately, this future did not materialize when the 24-year old Hernandez was arrested in June 2013 for the murder of his friend, Odin Lloyd. In 2015, Hernandez was found guilty of first-degree murder and sentenced to life in prison. In April 2017, Hernandez was found dead by strangulation in an apparent suicide in his jail cell.
Sadly, other NFL players have met similar ends off the field, such as two-time Super Bowl champion Dave Duerson who shot himself to death at age 50 years old in 2011 and 12-X Pro Bowl linebacker Junior Seau who committed suicide at age 43 years old in 2012.
Post-mortem examination of Hernandez’s brain was performed demonstrating particularly severe abnormalities consistent with chronic traumatic encephalopathy (CTE). According to the pathologist of record, the changes observed in Hernandez’s brain were similar to what was seen in the brains of former football players who were decades older than Hernandez.
The term chronic traumatic encephalopathy (CTE) describes a neurodegenerative disease of the brain defined by brain pathology including phosphorylated tau deposits in particular brain areas and locations. CTE is observed in individuals who compete in high-impact sports such as boxing and American football. The findings are believed to be caused by repetitive mild traumatic brain injuries. Currently, CTE can only be established definitively after death with pathological examination.
Affected individuals with CTE may demonstrate a progressive condition with non-specific and delayed features, including cognitive and/or behavioral problems. Memory difficulties, reduced attention, impaired concentration, irritability, violence to self and others, depression, and other mood disorders are observed.
CTE was first discovered and results published by Dr. Bennet Omalu, a forensic pathologist originally at Allegheny County Coroner’s office in Pittsburgh. His story was highlighted in the 2015 Will Smith movie, “Concussion.” Dr. Omalu studied the brain of NFL player Mike Webster. Webster was considered one of the best centers in NFL history, winning four Super Bowls with the Pittsburgh Steelers. Webster’s post-NFL life was extremely difficult, with periods of homelessness and living in his truck. He died at the age of 50 years old from a heart attack.
The Journal of the American Medical Association (JAMA) recently published the largest study to date of deceased football players (2017:318(4):360-370). In a sample of 202 brains donated by players at all levels of play of American football, 177 brains (87%) showed neuropathological findings consistent with CTE, including 110/111 (99%) of NFL players. The prevalence of CTE was correlated with level of play, with a significantly fewer pre-high school and high-school players demonstrating CTE (3/16 individuals) and a much higher frequency with college players (48/53). Severity of the pathological findings was also greater in the college and professional group. Despite these remarkable findings, selection bias is present, in that sampled brains were not randomly or prospectively evaluated, but instead donated from individuals who may have experienced cognitive or behavioral symptoms during life; thus, true prevalence of the condition cannot be accurately estimated from this study.
In addition to the pathological findings, the study authors performed telephone interviews with surviving family members. Of those individuals with brain pathology demonstrating mild CTE (27/202), 96 percent had behavioral or mood symptoms, 85% had cognitive abnormalities, and 33 % had signs of dementia. Of those with severe CTE (84/202), 89% had behavioral or mood symptoms, 95% had cognitive abnormalities, and 85% had signs of dementia. Thus, even milder CTE findings were associated with significant behavioral, mood, or cognitive abnormalities.
The understanding of CTE is in its infancy. Scientists are just starting to create detailed neuropathologic criteria for diagnosis. The desire to identify biomarkers of the condition has led to blood testing, imaging studies, and cerebrospinal fluid evaluation. There is currently promise in the use of advanced imaging, especially MRI findings with attention to the brain volume in, particularly sensitive areas.
Hopefully, we will soon be able to identify more risk factors for CTE and be able to reduce the occurrence of this disorder.
