Also look at medical history before football, family history, substance abuse, PEDs, chemical exposures from practicing/playing on grass and/or turf...
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"...First, a major limitation is ascertainment bias associated with participation in this brain donation program. Although the criteria for participation were based on exposure to repetitive head trauma rather than on clinical signs of brain trauma, public awareness of a possible link between repetitive head trauma and CTE may have motivated players and their families with symptoms and signs of brain injury to participate in this research. Therefore, caution must be used in interpreting the high frequency of CTE in this sample, and estimates of prevalence cannot be concluded or implied from this sample....
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Nice disclaimer. It is the equivalent of throwing packets of heroin to a clamoring crowd of junkies, then saying in a monotone "You really shouldn't use this heroin, we didn't check it, it could be pure and kill you, or it could be common baking soda..."
They WANT people to take this and run with it. The disclaimer just applies a veneer of responsibility and impartiality. It is nothing of the sort. They people throwing packets of something that could be heroin to a bunch of junkies know they are going to inject it into their veins, and the same mindset applies to the authors of this paper throwing it to an ignorant mob who they know are going to disseminate it as if it were the God's truth.
And furthermore, if you gave them truth serum, they would smile and say: "Yes, we know it is wrong to mislead people. But it is for a good cause...
Now, Gee whiz. Who does that sound like? Sure doesn't sound like speech from people who think Ronald Reagan is a swell guy. Sounds more like the people who think Saul Alinsky is a swell guy.