Former NFL players believe they have CTE

(CBS, KYMA/KECY) - Following the news of Brett Favre's Parkinson's diagnosis, a significant number of former NFL players believe they have CTE.

Nearly 2,000 former NFL players participated in a Harvard University questionnaire on perceived CTE symptoms, and more than third self-reported that they believe they have CTE.

The disease, which is associated with repeated hits to the head, can currently only be diagnosed after death with an autopsy.

The study participants, who played professional football between 1960 and 2020, described having cognitive difficulties, headaches, low testosterone, and other symptoms stemming from their days on the field.

Study author Dr. Rachel Grashow says while CTE can't be treated, doctors can help with many of the symptoms.

"While we can't go back and change if they have head injuries, and we can't know if they actually have it, there's actually so much we can do that we can learn from this study. Can we go after their low testosterone, their depression, can we go after sleep apnea, all the things that are actually impacting their cognitive function now, that we can do something about."

Dr. Rachel Grashow, Harvard T. H. Chan School of Public Health

Symptoms of CTE include cognitive impairment, behavioral changes, mood disorders, and reduced motor function.

In the group of players who think they have CTE, a quarter said they have frequent suicidal thoughts.

This season, the NFL began allowing players to wear guardian caps, which have extra padding meant to reduce helmet-on-helmet impact.