Clinical Features of Patients with Alzheimer's Disease and a History of Traumatic Brain Injury

Introduction: Traumatic brain injury (TBI) has been associated with a greater risk of developing Alzheimer's disease (AD). Less is known about the clinical features of AD patients with TBI history. The objective of this study was to examine whether a history of TBI and specific injury characteristics are associated with differences in age of disease onset, cognitive features, and neuropsychiatric symptoms (NPSs) in AD patients. Methods: Biomarker-proven AD patients (CSF or amyloid PET) were selected from the Amsterdam Dementia Cohort. TBI events were classified by age at injury (TBI <25 or ≥25 years) and TBI severity (loss of consciousness, multiple events). Cognitive composite scores were calculated from results of a neuropsychological test battery. NPSs were assessed with the Neuropsychiatric Inventory Questionnaire (NPI-Q). Linear regression analyses were utilized to examine associations between TBI, TBI characteristics, and clinical outcome measures. Results: Among the 1,755 selected AD patients (mean age = 65.2 years), 166 (9.5%) had documented ≥1 TBI in their medical history. Overall, TBI history was not related to differences in age of disease onset, but age at injury <25 years old was associated with 2.3 years earlier age at symptom onset (B = -2.34, p = 0.031). No significant associations were found between TBI history or TBI characteristics and differences in cognition or NPSs. Conclusion: Our results underscore previous findings on the vulnerability of the brain during critical maturation phases and suggest that an early TBI may contribute to lower resilience to neurodegenerative changes

Rationale and design of the “NEurodegeneration: Traumatic brain injury as Origin of the Neuropathology (NEwTON)” study: a prospective cohort study of individuals at risk for chronic traumatic encephalopathy

Background: Repetitive head injury in contact sports is associated with cognitive, neurobehavioral, and motor impairments and linked to a unique neurodegenerative disorder: chronic traumatic encephalopathy (CTE). As the clinical presentation is variable, risk factors are heterogeneous, and diagnostic biomarkers are not yet established, the diagnostic process of CTE remains a challenge. The general objective of the NEwTON study is to establish a prospective cohort of individuals with high risk for CTE, to phenotype the study population, to identify potential fluid and neuroimaging biomarkers, and to measure clinical progression of the disease. The present paper explains the protocol and design of this case-finding study. Methods: NEwTON is a prospective study that aims to recruit participants at risk for CTE, with features of the traumatic encephalopathy syndrome (exposed participants), and healthy unexposed control individuals. Subjects are invited to participate after diagnostic screening at our memory clinic or recruited by advertisement. Exposed participants receive a comprehensive baseline screening, including neurological examination, neuropsychological tests, questionnaires and brain MRI for anatomical imaging, diffusion tensor imaging (DTI), resting-state functional MRI (rsfMRI), and quantitative susceptibility mapping (QSM). Questionnaires include topics on life-time head injury, subjective cognitive change, and neuropsychiatric symptoms. Optionally, blood and cerebrospinal fluid are obtained for storage in the NEwTON biobank. Patients are informed about our brain donation program in collaboration with the Netherlands Brain Brank. Follow-up takes place annually and includes neuropsychological assessment, questionnaires, and optional blood draw. Testing of control subjects is limited to baseline neuropsychological tests, MRI scan, and also noncompulsory blood draw. Results: To date, 27 exposed participants have finished their baseline assessments. First baseline results are expected in 2023. Conclusions: The NEwTON study will assemble a unique cohort with prospective observational data of male and female individuals with high risk for CTE. This study is expected to be a primary explorative base and designed to share data with international CTE-related cohorts. Sub-studies may be added in the future with this cohort as backbone