Between 2016 and 2021, 878 former NFL players died, and 235 donated their brains for study, with 215 showing CTE pathology according to research led by Daniel Daneshvar. The study, conducted by Mass General Brigham, Boston University, and the Concussion CTE Foundation, found CTE only diagnosable postmortem and occurring at rates far above the general population. Sources note selection bias in brain donation and an unverified NFLPA statement on the findings.