Mount Sinai Study Reveals Rarity of CTE in Isolated Head Injuries

A recent study conducted by researchers at the Mount Sinai Health System found that Chronic Traumatic Encephalopathy (CTE) is infrequently diagnosed among individuals with isolated brain injuries. The research, published on October 18, 2025, in the Journal of Neuropathology & Experimental Neurology, enhances the understanding of CTE, a neurodegenerative condition linked to repetitive head trauma.

CTE, characterized by abnormal accumulations of tau protein in the brain, has primarily been associated with individuals exposed to extensive repetitive head impacts, particularly in contact sports like American football. This study highlights the need for broader research beyond the narrow focus on professional athletes, as it shows that CTE is rare in people with isolated traumatic brain injuries or less extensive head impacts.

Kristen Dams-O’Connor, PhD, Director of the Brain Injury Research Center at Mount Sinai, emphasized the significance of this research in clarifying the prevalence of CTE. “Most prior studies have been conducted on selected samples of male American football players, which limits our understanding of the disease in individuals with various head trauma exposures,” she stated.

The Mount Sinai research team examined postmortem brain tissue from 47 donors as part of the Late Effects of Traumatic Brain Injury Project, which spans from 2018 to 2024. This project aims to study over 500 individuals living with traumatic brain injury (TBI) who undergo clinical assessments and neuroimaging. For this particular study, comprehensive trauma histories were gathered through medical records, autopsy reports, and interviews with families.

Among the 47 decedents analyzed, only seven were found to have autopsy-confirmed CTE. Notably, six of these individuals had histories of extensive repetitive head impacts, while one individual had experienced two severe isolated TBIs without a background of repetitive impacts. The team utilized advanced neuropathological methods, including tau immunohistochemistry, and postmortem MRI scanning to identify subtle lesions that may contribute to the development of CTE.

“While our findings reaffirm the connection between CTE and extensive, repeated head impacts, they also highlight the necessity to explore how different types of head trauma are related to CTE risk,” said Enna Selmanovic, PhD candidate and first author of the paper. “Continued research in diverse populations is essential to move the conversation from assumptions to evidence-based understanding.”

To address public confusion surrounding terminology, the research team clarified definitions of key terms related to brain injuries. These include:

– **Traumatic brain injury (TBI)**: A blow to the head resulting in loss or alteration of consciousness, or acute symptoms such as imbalance or vision changes.
– **Blow to the head**: An isolated injury that does not meet the criteria for TBI.
– **Repetitive head impacts**: A series of impacts sustained over time, potentially leading to acute TBI symptoms.
– **Extensive repetitive head impacts**: Exposure to five or more years of repetitive head impacts.

The study’s findings are crucial for informing the public and healthcare professionals about the actual risk of CTE in individuals with less severe head trauma. As the conversation around brain injury continues to evolve, this research underscores the importance of community-based studies that encompass a broad spectrum of individuals, not just those from high-risk sports backgrounds.

The Mount Sinai Health System is recognized as one of the largest academic medical systems in the New York metro area, consisting of numerous hospitals, outpatient practices, and research facilities. Its commitment to advancing health through innovative research and comprehensive care remains a cornerstone of its mission.