Traumatic brain injury (TBI) is a leading public health concern and a risk factor for developing neurodegenerative diseases, including Alzheimer’s disease and chronic traumatic encephalopathy (CTE). Often experienced by military personnel, athletes, and others experiencing multiple head traumas, CTE is a progressive disease which can lead to cognitive impairment and dementia. Given that CTE frequently begins its onset at a relatively young age, this condition is particularly alarming for individuals’ quality of life, as it contributes to a broad scope of functional losses. CTE is clinically characterized by cognitive decline, mood disorders, and behavioral problems, including depression and explosivity.
The pathology of CTE is related to abnormal accumulation of p-tau, a protein found in the brain. Because CTE can only be definitively diagnosed by examining the brain for p-tau proteins after a patient has died, CTE can be difficult to detect in those living with the disease. A diagnosis is a necessary tool for clinicians to provide adequate treatment of CTE, and researchers have been focused on finding diagnostic markers during life that are related to postmortem studies.
In a postmortem study of 11 brains of former soccer and rugby players who developed dementia, three patients showed no CTE, three patients received an integrated diagnosis of CTE with dementia, and five patients showed dementia with CTE as a comorbidity. These results suggest that CTE is not always the primary cause of dementia in those with TBI, and that other neurological mechanisms may be at play. Despite having similar clinical presentations, the prevalence of mixed neurodegenerative pathology in CTE patients makes it challenging to establish accurate clinical diagnoses.
In recent years, CTE has gained media attention due to findings of widespread CTE in professional football players and scientists’ understanding of the disease is constantly evolving with new discoveries. As clinicians and researchers work to improve their understanding of the disease mechanisms, risk factors, and prevention, it is important for families of people at higher-risk of CTE, such as veterans and athletes, to remain up-to-date on information on current guidelines, diagnostic advances, and future directions.
Who is at risk for CTE?
- Athletes, veterans, and other people with multiple TBIs. The main causes of CTE are repetitive head impacts with moderate to severe cases of TBI. Athletes who participate in a range of high-risk sports, including football, soccer, or rugby, should be aware of the potential lifelong consequence of this neurodegenerative disease. Moreover, combat veterans who experienced a blast injury and those who have had a single traumatic head injury are also at risk, and should not be overlooked in the diagnostic process.
What are the current measures of CTE?
- Cognitive and neuropsychiatric symptoms. While CTE cannot currently be diagnosed during a patient’s life, symptoms of cognitive decline and neuropsychiatric disorders are usually present, and these combined with a history of head injury may indicate CTE. The major problem facing CTE diagnostics is specificity, as many current guidelines for predicting CTE also point to general, nonspecific neurodegeneration.
What is currently being researched?
- Diagnostics, imaging and genetics. A current and ongoing study is assessing the predictive validity of diagnostic markers in 240 male patients who were former college or professional athletes. The goal of this research is to discover specific clinical biomarkers, genetic factors, and imaging patterns associated with CTE, in order for clinicians to form accurate and effective diagnoses.
References:
Lee E, Kinch K, Johnson V, et al. Chronic traumatic encephalopathy is a common co‑morbidity, but less frequent primary dementia in former soccer and rugby players. Acta Neuropathologica. (May 2019).
VanItallie T. Traumatic brain injury (TBI) in collision sports: Possible mechanisms of transformation into chronic traumatic encephalopathy (CTE). Elsevier. (September 2019).
Alosco M, Mariani M, Adler C, et al. Developing methods to detect and diagnose chronic traumatic encephalopathy during life: rationale, design, and methodology for the DIAGNOSE CTE Research Project. Alzheimer’s Research & Therapy. (August 2021).