Layman questions about CTE (brain injuries)

Factual Questions
1

AIUI, CTE is basically “injury-caused Alzheimer’s”?

  1. How many subconcussive impacts does it generally take to cause CTE? Just a few, or hundreds?

  2. Is CTE something that, once “triggered,” begins cascading and increasing of its own, like cancer (even if you have no further head impacts, it will still grow and worsen) or is it something that only grows each time you bang your head?

  3. Is CTE actually harmful to the rest of the body (i.e., does it kill like Alzheimer’s, or is it something that only affects your memory and thinking but doesn’t kill or harm the rest of your body?)

2

Follow-up questions:

  1. Does EVERY impact to your head contribute to CTE, and it’s like you are putting brain-damage units into a piggy bank and once it hits a certain level you will get CTE?

  2. Does CTE come in “mild” and “severe” forms or is it always CTE, just like there’s no such thing as “mild Alzheimers?”

3

My understanding is that the answer to #1 (and possibly #2, as well) is “no one knows, yet.” The science on CTE is still developing, and, as CTE can only be diagnosed in an autopsy (i.e., there’s no known way, today, to definitively diagnose it in a living person), a lot of how it develops is still not really known.

Adding to that is that the brains of deceased former football players (for example) which have been studied have nearly always been specifically those which the players (or their families) ask to have studied for evidence of CTE, based on the deceased’s emotional and neurological issues before passing. In like 98% of those cases, evidence of CTE has been found – but we have no idea how prevalent CTE is among people who played football, generally, because the vast majority of former players aren’t undergoing that sort of examination after death.

So, a lot of the progression of the disease simply isn’t well-understood, as I understand it.

4

This

- is a layman-pitched documentary in the subject. Alan Shearer was a professional footballer (the other sort), England international and noted header of the ball, so he has an interest in the subject.

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5

It appears that it also has negative impacts on other neurological functions, such as issues with balance and walking, Parkinsons-like tremors, and speech.

In addition, it appears that there may a link between CTE and ALS, as a number of former NFL players (including Dwight Clark, Steve Gleason, and Kevin Turner) have been diagnosed with ALS.

6

You think about football players which have these problems, but it never occurred to me it would also be a problem with Navy Seals:

Since the New York Times is paywalled I am including a non-paywalled Daily Mail article which summarizes much of it: