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How Chronic Traumatic Encephalopathy Works


The Symptoms
Neurology researcher Ann Mckee stores brains at the Bedford Veterans Administration Medical Center, repository for the Brain Bank, where she's studying the pathology of concussive head trauma in ex-athletes.
Neurology researcher Ann Mckee stores brains at the Bedford Veterans Administration Medical Center, repository for the Brain Bank, where she's studying the pathology of concussive head trauma in ex-athletes.
Brian Cahn/ZUMA Press/Corbis

When neuropathologists look at a brain with CTE they might see any of a number of features, such as scar tissue, a shrunken, atrophied cerebral cortex and medial temporal lobe, neurofibrillary and astrocytic tangles in the temporal and frontal cortices and limbic regions, and degeneration of axons and white matter fiber bundles [source: McKee et al., "Spectrum"].

Of course, unless you're a medical professional, preferably a neurologist, none of this means much. Suffice it to say that the brain looks unhealthy — and unhealthy in a specific way that indicates it's been bounced around inside the skull far more than it should have been.

For the layperson, the symptoms of CTE are much more familiar. Although the condition is caused by injury rather than disease, people who suffer from it have symptoms that resemble those of people with other neurodegenerative illnesses such as Parkinson's and Alzheimer's, although CTE usually shows up much earlier than those diseases (often when people are in their 40s).

The condition can be progressive, and there are three stages of deterioration. Sometimes accompanied by dizziness and headaches, the first stage includes:

  • Shorter attention spans
  • Difficulty concentrating and remembering
  • Increasing disorientation and confusion leading to poor reasoning, judgment and problem-solving
  • Aggression and poor impulse control

In the second stage, people with CTE can begin to behave oddly and experience memory loss. Finally, people suffering from severe CTE can enter a third stage characterized by symptoms such as slowing movements, staggering, difficulty speaking, trembling and deafness [source: McKee et al., "Athletes"].

However, just because a person exhibits these symptoms doesn't necessarily mean he or she has CTE. One of the largest problems facing CTE researchers is that they can diagnose the disease only through special screening methods during an autopsy. In other words, as of January 2016, CTE diagnosis is post-mortem only.

As if that weren't enough, the other big problem is that there's no known cure for the condition. The best thing we can hope for is to prevent the brain trauma from happening in the first place. But exactly how to do that is an open question. How much head-banging can a brain put up with? Does it matter at what angle you get hit, how many times you get hit, how thick your neck muscles are? For the moment, it seems that kids under 14 are more at risk, and girls are more vulnerable than boys. In both groups, the risk is tied to having thinner or weaker necks, among other factors. But the research on how to prevent, never mind cure, CTE is still in its early days [source: Sneed].


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