Traumatic brain injury history moderates age-related episodic memory change in older veterans: the DOD-ADNI longitudinal cohort study

BACKGROUND: Traumatic brain injury (TBI) has been associated with increased risk of dementia and cognitive decline, but its relationship with age-related cognitive trajectories remains unclear. This study examined associations between TBI history and age-related changes in cognitive function in aging military veterans. METHODS: Data from the Department of Defense-Alzheimer's Disease Neuroimaging Initiative (DOD-ADNI) repository were used to evaluate whether TBI history moderates the relationship between age and longitudinal change in domain-specific cognitive performance. To investigate these relationships, this study utilized data from neuropsychological assessments collected at baseline and 12-month timepoints from a sample consisting of 203 Vietnam War veterans, 99% of whom were male, aged 60-84 years, with varying TBI histories. RESULTS: Results revealed that TBI history moderated the association between age and change in episodic memory. Older age was associated with greater memory decline among individuals with TBI. No interaction effects were observed for executive functions or language. CONCLUSIONS: These findings suggest that TBI history is associated with differences in age-related episodic memory change and highlight the importance of considering TBI history in studies of cognitive aging. Considering the modest proportion of variance explained by the interaction and homogeneous veteran sample, additional research is warranted.