What is CTE?

Chronic Traumatic Encephalopathy (CTE) is a progressive degenerative disease of the brain found in athletes (and others) with a history of repetitive brain trauma. This trauma, which includes multiple concussions, triggers progressive degeneration of the brain tissue, including the build-up of an abnormal protein called tau.  These changes in the brain can begin months, years, or even decades after the last concussion or end of active athletic involvement.  The brain degeneration is associated with memory loss, confusion, impaired judgment, paranoia, impulse control problems, aggression, depression, and, eventually, progressive dementia.

Figure: Tau immunostained sections of medial temporal lobe from 3 individualsTop left: Whole brain section from a 65 year old control subject showing no tau protein deposition; Bottom left:Micrgoscopic section from 65 year old control subject also shows no tau protein; Top middle: Whole brain section from John Grimsley showing abundant tau protein deposition in the amygdala and adjacent temporal cortex; Bottom middle: Microscopic section showing numerous tau positive neurofibrillary tangles and neurites in the amygdala; Top right: Whole brain section from a 73 year old world champion boxer with severe dementia showing very severe tau protein deposition in the amygdala and thalamus; Bottom right: Microscopic section from a 73 year old world champion boxer with severe dementia showing extremely dense tau positive neurofibrillary tangles and neurites in the amygdala

First described as “punch drunk”  syndrome and dementia pugilistica, CTE was first described in 1928 by New Jersey pathologist  Harrison Martland in “Martland HS: Punch drunk. JAMA 91:1103–1107, 1928” in which he noted symptoms such as slowed movement, tremors, confusion, and speech problems typical of the condition. In 1973, agroup led by J.A. Corsellis described the typical neuropathological findings of CTE after post-mortem examinations of the brains of 15 former boxers.

The term “Chronic Traumatic Encephalopathy” appears in the medical literature as early as 1966 and is now the preferred term.  Through 2009 there were only 49 cases described in all medical literature since 1928, 39 of whom were boxers.  Many thought this was a disease exclusive to boxers, although cases have been identified in a battered wife, an epileptic, two mentally challenged individuals with head-banging behavior, and an Australian circus performer who was also involved in what the medical report authors referred to as “dwarf-throwing.”

CTE remained under the radar when a Pittsburgh medical examiner named Bennet Omalu identified CTE in two former Pittsburgh Steelers who died in his jurisdiction in 2002 and 2005. He published his findings, drawing the attention of SLI co-founder Chris Nowinski, who worked with families to deliver three more cases that Dr. Omalu and others diagnosed with CTE, including SLI’s first case, former WWE wrestler Chris Benoit.

In 2008 Nowinski, Dr. Robert Cantu, co-founders of SLI, partnered SLI with Drs. Ann McKee and Robert Stern to create the Center for the Study of Traumatic Encephalopathy (CSTE) at Boston University School of Medicine, the world’s first center dedicated to studying CTE. In 2009 Dr. McKee, a neuropathologist and one of the world’s foremost neurodegenerative disease experts, published the seminal paper on all known cases of CTE ever identified in the medical literature, adding three new cases from the CSTE to bring the total to 52.

In the CSTE’s first twelve months, we have identified CTE in 17 of 18 deceased contact sport athletes, ranging in age from 18 to 83. Based on these findings, there is grave concern that CTE affects far more athletes than previously believed. To learn more, visit the CSTE at Boston University School of Medicine.