In two recent posts we explored Traumatic Brain Injury (TBI) and its causation of dementia. Today we will delve into Chronic Traumatic Encephalopathy, commonly referred to at CTE. The brain disease has gained much more exposure as of late, especially in relation to athletes who have developed the disease from concussion events. CTE is known to cause progressive dementia.
Chronic Traumatic Encephalopathy (CTE) is a degenerative brain disease found in athletes, military veterans and others with a history of repetitive brain trauma. In CTE, a protein called Tau forms clumps that slowly spread throughout the brain, killing brain cells. CTE has been seen in people as young as 17, but symptoms do not generally begin appearing until years after the onset of head impacts.
Early symptoms of CTE usually appear during the affected individuals late 20s or 30s, and affect a patient’s mood and behavior. Some common changes seen include impulse control problems, aggression, depression and paranoia.
During the progression of the disease, some patients experience problems with thinking and memory loss, including confusion, impaired judgment and eventually progressive dementia. Cognitive symptoms tend to appear later than mood and behavioral symptoms, and generally first appear in a patient’s 40s or 50s. Patients may exhibit one or both symptom clusters. In some cases, symptoms worsen with time (even if the patient suffers no additional head impacts). In other cases, symptoms may be stable for years before worsening.
HISTORY OF CTE
CTE was first described in 1928 by Dr. Harrison Martland when observing a group of boxers as having “punch drunk syndrome.” Over the next 75 years, researchers reported similarities in studies of boxers and “traditional” victims of brain trauma, but fewer than 50 cases were confirmed. In 2005, a pathologist named Bennet Omalu published the first evidence of CTE in the former American football player Pittsburgh Steeler Mike Webster. That story was made into the 2015 film Concussion, starring Will Smith as Omalu.
CAUSES OF CTE
The best available evidence tells us that CTE is caused by repetitive hits to the head sustained over a period of years. This doesn’t mean a handful of concussions: most people diagnosed with CTE suffered hundreds or thousands of head impacts over the course of many years playing contact sports or serving in the military. And it’s not just concussions: sub-concussive impacts, or hits to the head that don’t cause full-blown concussions, are suspected to be the biggest factor.
CTE HIGH RISK GROUPS
Every person diagnosed with CTE has one commonality — a history of repetitive hits to the head. CTE is most often found in contact sport athletes and military veterans, likely because these are some of the only roles in modern life that involve purposeful, repetitive hits to the head. CTE has been found in individuals whose primary exposure to head impacts was through tackle football, the military, hockey, boxing , rugby, soccer, pro wrestling, and, in fewer than three cases each, baseball, basketball, intimate partner violence, and individuals with developmental disorders who engaged in head banging behaviors.
Importantly, not everyone who has suffered repetitive hits to the head will develop CTE. There are several risk factors at play that make some people more susceptible to develop CTE than others, including:
Age of first exposure to head impacts
Athletes who begin playing contact sports at younger ages are at greater risk for CTE. Several published studies show that exposure to head impacts before age 12 is associated with worse outcomes than starting after age 12.
Length of exposure to head impacts
Athletes with longer careers playing contact sports are at greater risk than athletes with shorter careers. Among those diagnosed with CTE, athletes with longer careers are more likely to have more severe pathology than those with shorter careers.
There are very likely other risk factors that have yet to be discovered, including possible genetic differences that make some people more prone to develop CTE than others. More research will help scientists determine what those factors might be, and could help us understand how to prevent and treat the disease.
Like Alzheimer’s Disease, currently CTE can only be diagnosed after death through brain tissue analysis. Doctors with a specialty in brain diseases slice brain tissue and use special chemicals to make the Tau clumps visible. They then systematically search areas of the brain for Tau clumps with a unique pattern specific to CTE. The process can take several months to complete, and the analysis is not typically performed as a part of a normal autopsy. In fact, until recently there were relatively few doctors who knew how to diagnose CTE.
In 2015, researchers collaborated with the National Institutes of Health to develop diagnostic criteria for CTE so that any neuropathologist familiar with brain diseases could accurately diagnose CTE. This important work has made it possible for more and more scientists to be on the lookout for CTE, helping accelerate progress.
TREATMENT OF CTE
It’s obviously difficult to treat a disease that can only be diagnosed posthumously. However, there are things patients concerned they have CTE can do to address their symptoms and find relief. Most treatments for CTE involve identifying the symptoms that are causing patients the most difficulty, and treating those symptoms with targeted therapies.
Mood changes, including depression, irritability and anxiety, can be treated with cognitive behavioral therapy. Working with a cognitive behavioral therapist can help patients develop strategies that help them manage the particular mood symptoms that are causing the greatest problems.
A variety of treatment options exist for headache, including craniosacral therapy, massage, acupuncture or medications. Working with a doctor to determine the type of headache is helpful for determining the best treatment options.
Memory training exercises, including consistent note taking strategies, can be helpful for continuing a patient’s activities of daily living, despite increasing difficulty with memory.