Age of dementia onset and death in chronic traumatic encephalopathy.

Background: Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive head impact (RHI) exposure. The clinical presentation of CTE can include cognitive impairment, with progression to dementia. Currently, CTE can only be definitively diagnosed postmortem; most reports of the associated clinical syndrome come from retrospective informant interviews. In this setting, characterizing the clinical course can be biased because donors may have died from causes unrelated to CTE. To minimize this selection pressure and more accurately report average age of dementia and death in CTE, we identified brain donors with high stage CTE who died from neurodegenerative disease. Method: Donors with RHI exposure from contact sports and/or military service were eligible for the Understanding Neurologic Injury and Traumatic Encephalopathy (UNITE) Brain Bank. CTE neuropathological diagnosis and staging were assessed using validated criteria. Dementia diagnosis was determined by clinical consensus and dementia onset age was defined as the age that informants first reported functional impairment on a standardized scale of activities of daily living (Functional Activities Questionnaire, FAQ). Causes of death were determined from medical records, death certificate review, and informant interviews. Donors with a neuropathological diagnosis of high stage CTE (III or IV) and a neurodegenerative cause of death were included in the current study. Result: 186 donors met inclusion criteria. Football was the most common type of RHI exposure (172; 92.5%). Mean age of dementia onset was 70.2 (SD = 7.4; range = 48‐93) and the mean age of death was 77.1 (SD = 7.8; range = 54‐97). Mean time from dementia diagnosis to death was 6.9 years (SD = 4.6; range = 0‐24). 136 donors (73.1%) had other comorbid neurodegenerative diseases, including 84 (45.4%) with Alzheimer's disease, 58 (31.2%) with Lewy body disease, and 28 (15.1%) with frontotemporal lobar degeneration. Compared to donors with CTE and comorbid neurodegenerative diseases, donors with CTE but without comorbid neurodegenerative diseases did not significantly differ in age at dementia onset, age at death, and time from dementia diagnosis to death. Conclusion: Among brain donors with high stage CTE who died from neurodegenerative disease, approximately 75% had late onset‐dementia (i.e., age of dementia onset >65 years) and died within 10 years of dementia diagnosis. [ABSTRACT FROM AUTHOR]