Study Reveals Chronic Traumatic Encephalopathy Rare in Isolated Brain Injuries

A recent study conducted by the Brain Injury Research Center of Mount Sinai has found that Chronic Traumatic Encephalopathy (CTE) is infrequent among individuals who have experienced isolated brain injuries. Published on October 18, 2025, in the Journal of Neuropathology & Experimental Neurology, the research sheds light on CTE, a neurodegenerative condition often linked to repeated head trauma.

CTE has been predominantly observed in individuals with prolonged exposure to repetitive head impacts, particularly among athletes in contact sports like American football. The study identifies a significant distinction: CTE is rarely diagnosed in those who have not experienced extensive head trauma.

Kristen Dams-O’Connor, PhD, who directs the Brain Injury Research Center and serves as the paper’s senior author, emphasized the need for broader research. “Our study underscores that CTE is rare among individuals with lower amounts of repetitive head impact and in those with isolated traumatic brain injuries,” she noted. Dams-O’Connor also highlighted the importance of community-based research that goes beyond brain donations from specific populations, such as professional athletes.

Understanding CTE and Its Relation to Brain Injuries

CTE is characterized by an abnormal accumulation of tau protein in the brain, which is associated with head trauma. While previous studies have primarily focused on male American football players, the current research included a more varied sample, allowing for a better understanding of CTE prevalence in different contexts of head injury.

The Mount Sinai study analyzed postmortem brain tissue from 47 donors as part of the Late Effects of Traumatic Brain Injury Project, which ran from 2018 to 2024. This project includes over 500 individuals living with traumatic brain injuries (TBI), who have undergone clinical assessments and neuroimaging throughout their lives. Researchers gathered comprehensive trauma histories through medical records, autopsy reports, and structured family interviews.

Among the 47 decedents, autopsy-confirmed CTE was identified in seven cases. Notably, six of these individuals had a history of extensive repetitive head impacts, while one had experienced two severe isolated TBIs without repetitive impacts. This finding indicates that the link between CTE and repetitive head trauma is significant but not absolute.

Clarifying Terminology and Research Implications

The study also addressed the common confusion regarding terms associated with brain injuries. To clarify:

– **Traumatic brain injury (TBI)**: A blow to the head that results in loss or alteration of consciousness, or symptoms such as imbalance or vision changes.
– **Blow to the head**: An isolated injury that does not meet TBI criteria.
– **Repetitive head impacts**: A series of head impacts sustained closely over time, possibly without acute TBI symptoms.
– **Extensive repetitive head impacts**: Defined as exposure to repetitive head impacts for five or more years.

Enna Selmanovic, a PhD candidate at the Icahn School of Medicine and the paper’s first author, remarked on the significance of the findings. “This study adds to our understanding of how common or rare CTE really is,” she said. “While the findings continue to suggest that CTE is linked to extensive, repeated head impacts, they also underscore the need to identify additional risk and protective factors.”

The study’s outcomes emphasize the necessity of further research into the relationship between various types of head trauma and the risk of CTE. As more diverse populations are studied, the conversation surrounding CTE will move from assumptions to evidence-based conclusions.

The Mount Sinai Health System continues its commitment to advancing health knowledge and addressing complex medical challenges through innovative research and community engagement.