The Chronic Effects of Neurotrauma Consortium (CENC) multi-centre observational study: Description of study and characteristics of early participants

Primary objectives: To establish and comprehensively evaluate a large cohort of US veterans who served in recent military conflicts in order to better understand possible chronic and late-life effects of mild traumatic brain injury (mTBI), including those that may stem from neurodegeneration.Research design: Cross-sectional and prospective longitudinal.Methods and procedures: Inclusion criteria are prior combat exposure and deployment(s) in Operation Enduring Freedom, Operation Iraqi Freedom or one of their follow-on conflicts (collectively OEF/OIF). Effects of mTBI will be assessed by enrolling participants across the entire spectrum of mTBI, from entirely negative to many mTBIs. Longitudinal assessments consist of in-person comprehensive testing at least every 5 years, with interval annual telephonic testing. The primary outcome is the composite score on the NIH Toolbox neuropsychological test battery. Assessments also include structured interviews, questionnaires, traditional neuropsychological testing, motor, sensory and vestibular functions, neuroimaging, electrophysiology, genotypes and biomarkers.Main outcomes and results: The authors fully describe the study methods and measures and report demographic and exposure characteristics from the early portion of the cohort of OEF/OIF veterans.Conclusions: This centrepiece observational study of the Chronic Effects of Neurotrauma Consortium (CENC) is successfully launched and, within several years, should provide fertile data to begin investigating its aims.