• 215 of 235 donated brains showed signs of CTE

• Condition can only be diagnosed after death

• Symptoms include problems with memory and mood

At least one in four former NFL players who died between 2016 and 2021 was found to have had chronic ⁠traumatic encephalopathy (CTE), according to a study released on Tuesday.

Out of the 878 former players who died during that time frame, 235 donated their brains for study, researchers said, with 215 ⁠of those donated brains ⁠found to have CTE, ​a degenerative disease that can only definitively be diagnosed after death. CTE is associated with repeated blows to the head, including concussions. Symptoms include difficulty with attention and memory, dementia, mood disorders and headaches.