What is chronic traumatic encephalopathy (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, including symptomatic concussions as well as asymptomatic sub-concussive hits to the head. It is characterized by neurofibrillary tangles which are the result of abnormal TAL protein in the brain. Diffuse atrophy also occurs in the brain; around the cortex, the frontal lobe, the medial thalamus, the olfactory bulbs, the amygdala, many of the limbic structures, the hippocampus, and entorhinal cortex.
CTE is degenerative in that as an individual ages the symptoms of CTE are going to worsen. It occurs from a history of repetitive brain trauma. Typically CTE is not seen from just one hit to the head, it is from repetitive blows to the head. Not everybody who gets hit in the head repetitively is going to get chronic traumatic encephalopathy in a similar way that not everybody who smokes is not going to have cancer. However, the more hits the brain has, according to the research, the more likely a person is to be diagnosed with chronic traumatic encephalopathy.
CTE can be symptomatic or asymptomatic, meaning somebody with concussions or with repetitive brain trauma may not even show symptoms. If that was the case then every time a football player gets hit in the head they would be stumbling around in the field, being confused, having headaches, being nauseous. However, that doesn’t happen every single time somebody gets hit in the head.
Ann McKee, who’s a neuropathologist out of Boston University’s medical school, is a prominent researcher in CTE. Her research describes CTE in four stages. In the first stage of CTE there are not many symptoms, there might be some isolation of the TAL protein in the frontal lobes or maybe a little in the temporal lobes, but there is really not much going on.
In the second stage individuals are more likely to have headaches. They have difficulty with attention, concentration and language. Many of them have mood swings, depression and impulsivity. Some individuals will have suicidal thoughts at this stage.
Stage 3 is marked by symptoms of the previous stages in addition to possible addiction, visual-spatial deficits, cognitive deficits, and memory problems. Many of these individuals also have apathy; they are lacking empathy for others. Researchers have stated that 75% of individuals in stage three of CTE are also going to have significant cognitive impairment.
The fourth stage of CTE is commonly associated with advanced dementia. This is the last stage of CTE, and shows the most prominent effects. There is memory loss, cognitive problems, loss of attention and loss of concentration. In this stage there are many symptoms that affect everyday life significantly. Think about somebody with advanced Alzheimer’s disease - that is similar to what is seen in stage 4 of CTE. IN fact, CTE is commonly misdiagnosed as Alzheimer’s disease. In some stages it's commonly diagnosed as Parkinson’s disease, maybe frontotemporal dementia, Lewy body dementia, other neurodegenerative diseases, because currently CTE can only be diagnosed postmortem, much like Alzheimer’s disease.
The research is focusing on determining how to diagnose CTE before death. In this fourth stage 37% of people with CTE are also going to have Alzheimer’s, Parkinson’s, or some other type of disease. The research doesn’t currently know if CTE triggers the pathways in these other diseases, and if that causes another disease or if CTE just looks like another disease. It is difficult to diagnose CTE until the person has passed away.
Alyssa Coreno, MA, is a doctoral student at Case Western Reserve University in the program of Communication Sciences within the Department of Psychological Sciences. She currently works with adults with a variety of neurogenic communication disorders. Her research focuses on describing the cognitive communication deficits associated with repetitive head trauma in individuals with athletic experience.