Ex-Chiefs Johnson Fears CTE; Researchers Pursue Tests

Former Kansas City Chiefs running back Larry Johnson, 46, says severe memory lapses—including forgetting where he parked and becoming disoriented while driving—have led him to fear he may have chronic traumatic encephalopathy (CTE), a concern he has voiced for years. Johnson had an exceptionally heavy workload during his NFL career, but his symptoms do not establish that he has CTE or that football caused them. CTE can currently be confirmed only after death by examining brain tissue, leaving doctors unable to definitively diagnose the disease in living patients. Researchers are working toward tests that could identify CTE during life, including approaches using PET scans, which could help assess risk and evaluate treatments; experts caution that diagnostic tools remain in development. The urgency is underscored by research suggesting at least a quarter of NFL players who died from 2016 to 2021 may have had CTE, though experts note limitations in the study.