NFL players are Not all impaired
New finding on retired professional NFL players shows no linear association between concussion and cognitive impairment. Read this recent article by Lindy Fields, Nyaz Didehbani, John Hart, and Munro Cullum. https://www.researchgate.net/profile/Nyaz_Didehbani/publication/331607981_No_Linear_Association_Between_Number_of_Concussions_or_Years_Played_and_Cognitive_Outcomes_in_Retired_NFL_Players/links/5c895f60a6fdcc3817526125/No-Linear-Association-Between-Number-of-Concussions-or-Years-Played-and-Cognitive-Outcomes-in-Retired-NFL-Players.pdf