Two analyses of former NFL players who died between 2008 and 2021 examined brain donations for chronic traumatic encephalopathy. One study of 878 deaths from 2016-2021 found a minimum CTE prevalence of 24.5 percent across all deaths and up to 97.7 percent among 235 donors. A second analysis covering 1,712 deaths from 2008-2021 reported 93.2 percent CTE among 338 examined brains.