CTE is defined as a progressive neurodegenerative disease that causes brain damage similar to what’s seen in patients with Alzheimer’s disease, per the National Institutes of Health (NIH). There is a known link between repeated head trauma, contact sports, and the development of CTE.

Meiko Locksley, one of 152 athletes diagnosed with CTE before even reaching the age of 30 as part of the Boston University CTE Center’s 2023 study, never made it past college football and began exhibiting signs of the disease in his 20s.

The gunman in the deadly Midtown Manhattan shooting, Shane Tamura, wrote about the brain disease CTE in a note obtained by investigators.