by Daniel Rancier MD
Chronic Traumatic Encephalopathy (CTE) is a progressive neurodegenerative disorder that leads to premature death and is associated with diseases such as Alzheimer’s disease. Repeated mild traumatic brain injury from Contact Sports likely causes CTE.
Researchers have not fully determined the exact cause of CTE yet. We do know that it’s linked to a variety of contact sports including football, hockey, soccer, boxing, and rugby. At risk are athletes with repeated concussions and those with sub-concussions.
The repetitive and chronic nature of the head trauma is likely what is causing CTE. The diagnosis of concussion is not necessary. In fact, 16% of CTE cases do not have a history of concussion.
In published CTE cases, the time it took to show clinical symptoms of CTE was 14.5 years after the brain trauma occurred. Signs and symptoms of CTE show up at the mean age of 44.3 years. For CTE to develop, it took an average of 15.4 years of repeated concussions and sub-concessions in contact sports or military service. Finally, the mean age of death of those suffering from CTE was 59.3 years.
Interestingly NFL players over the age of 50 are five times more likely to develop dementia than the average person and death due to neurodegenerative disease is increased threefold. Of the former NFL players who have died and donated their brains for research over 90% of them have changes consistent with CTE.
CTE is a diagnosis that can only be made after death when analyzing the brain at autopsy. In people with CTE, there is the presence of protein in specific regions of the brain called Tau. Clinicians believe Tau protein is concentrated in the brain when there is a force from traumatic brain injury. This Tau protein is deposited in a unique pattern when a traumatic brain injury occurs. Researchers believe this pattern of Tau protein deposition is pathognomonic for CTE.
The symptoms of CTE include depression, suicidality, irritability, explosivity, violence, impulsivity, impaired memory, loss of executive functions, and decreased concentration. The signs of CTE include weakness, gait changes, Parkinsonism, and difficulty speaking to name a few. Within the published cases of CTE, many died of suicide, and about 45% developed dementia. In fact, those over age 60, 66% developed dementia.
Disturbing as this is, there is hope! The authors conclude that the presence of a few well-managed concussions is not sufficient to cause CTE! However, the importance of concussion recognition is critical, as the development of CTE seems to be linked to multiple concussions over the athlete’s lifetime especially if they are not recognized and treated.
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Curr Pain Headache Rep. 2015 October; 19(10): 47. Doi: 10.1007/s11916-015-0522-z