Severe CTE clearly linked to dementia
February 24, 2026
Severe CTE clearly linked to dementia
At a Glance
- Researchers found that severe chronic traumatic encephalopathy (CTE) was strongly associated with dementia and cognitive symptoms.
- The study provides the clearest evidence to date of the long-term impact of repeated head injuries on brain health.
Head injury is common among people who play contact sports, serve in the military, or are exposed to physical violence. Repetitive head impacts can lead to a progressive brain disorder called chronic traumatic encephalopathy (CTE). Currently, CTE can only be definitively confirmed by examining the brain after death. It is difficult to diagnose during life. CTE can be misdiagnosed as other neurodegenerative diseases, such as Alzheimer’s disease or other forms of dementia. To make a diagnosis during life, doctors rely on a patient’s history of repetitive head impacts and symptoms while ruling out other disorders.
To clarify the link between CTE and symptoms, researchers at Boston University led by Dr. Michael Alosco examined brains from 614 donors who were exposed to repetitive head impacts. None of the brain donors had neurodegenerative disease diagnoses other than CTE. The researchers also accounted for vascular injury, substance use, and age. The researchers gathered information about the donors’ mood, behavior, and thinking abilities. Results were reported in Alzheimer’s & Dementia on January 26, 2026.
The brains included 366 with CTE and 248 without. The researchers found that the people with more severe CTE (called stages III and IV) had worse cognitive and functional symptoms. Those with stage IV CTE were 4.5 times more likely to have had a dementia diagnosis than those without CTE. In contrast, milder CTE (stages I and II) was not linked to dementia, cognitive symptoms, or functional symptoms.
Mood and behavioral symptoms were not associated with any stage of CTE, even though these are common symptoms in people with repetitive head impacts. This suggests that these symptoms might be caused by other types of brain damage related to repetitive head impacts rather than CTE.
“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,” explains Dr. Amy Bany Adams, acting director of NIH’s National Institute of Neurological Disorders and Stroke, which funded the research.
“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 says.
Related Links
- Effects of repeated head trauma in young athletes
- Chronic traumatic encephalopathy in young athletes
- How football raises the risk for chronic traumatic encephalopathy
- Caring for concussions: More than a bump on the head
- Traumatic brain injury (TBI)
- What is dementia?
- Brain donation: A gift for future generations
- NIH NeuroBioBank—Why donate?
References
CTE Neuropathology Alone Associated with Dementia and Cognitive Symptoms. Layden RM, Groh JR, Miner AE, Kidd A, Nosek SB, Gil SG, Abdolmohammadi B, Lenio S, Nowinski CJ, Tripodis Y, Martin BM, Palmisano JN, Dwyer BC, Katz DI, Goldstein LE, Cantu RC, Stern RA, Stein TD, McKee AC, Daneshvar DH, Mez J, Alosco ML. Alzheimer's & Dementia: The Journal of the Alzheimer's Association. 2026 Jan;22(1):e71032. doi: 10.1002/alz.71032. PMID: 41589584.
Funding
NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and National Institute on Aging (NIA).
