I did read it. The study acknowledges that there may be bias since the only relatives donating brains are those who feel their loved one showed signs on brain damage, without a bunch of brains of players who'd never exhibited any signs the study is flawed.
Something like 1200 total NFL players died over the period where they received donors. For the sake of argument assume none of the rest had CTE and you still have a 9% rate which is huge. My concern is the college players who tested positive- most college players aren't getting nearly the compensation the pros are so you can't really talk about them knowingly making a trade off
