A Boston University study has tied advanced chronic traumatic encephalopathy (CTE) to sharply elevated dementia risk.
Researchers examined brains from 614 people with histories of repeated head impacts but no other neurodegenerative diseases. Of those, 366 showed CTE and 248 did not. The team assessed age, substance use, vascular injury, and data on mood, behavior, and cognition. Findings appeared in the January 2026 issue of Alzheimer’s & Dementia.
Only advanced CTE at stages III and IV correlated with serious cognitive and functional impairments.
Individuals with stage IV CTE faced 4.5 times the likelihood of a dementia diagnosis compared to those without CTE. Milder stages I and II showed no ties to dementia or major cognitive decline.
CTE revealed no direct connection to mood or behavioral issues, pointing instead to other brain damage from repetitive head trauma as a possible cause.
Dr. Michael Alosco led the Boston University team. The National Institutes of Health funded the work, which analyzed CTE in isolation after excluding other common neurodegenerative conditions.
“By examining hundreds of brains and ruling out other common neurodegenerative diseases, the team could look at CTE alone and linked it to symptoms reported during life,” said Dr. Amy Bany Adams, acting director of NIH’s National Institute of Neurological Disorders and Stroke.
“Establishing that cognitive symptoms and dementia are outcomes of CTE moves us closer to being able to accurately detect and diagnose CTE during life, which is urgently needed,” Alosco said.
CTE arises from repeated head injuries prevalent in contact sports, military service, and physical violence. The disease progresses but can be confirmed only postmortem and often resembles Alzheimer’s or other disorders. Clinicians during life use trauma history and symptoms while excluding alternatives.
