Suchergebnisse

OBJECTIVE: Cognitive complaints, such as attentional or memory concerns, are commonly reported by veterans diagnosed with post-traumatic stress disorder (PTSD) or a history of mild traumatic brain injury (mTBI). The degree to which those complaints actually map on to measurable cognitive deficits is unclear and is likely complicated by the severity of trauma-related sequelae. In the present study we sought to characterize the degree to which PTSD symptoms and mTBI accounted for the relationship of subjective cognitive complaints to objective cognitive performance, with the goal of facilitating the accurate assessment of trauma-exposed veterans complaining of cognitive decline. METHOD: A sample of 203 US military veterans previously deployed to Iraq and/or Afghanistan were assessed for PTSD severity, history of blast and impact mTBI, objective cognitive function, and subjective cognitive complaints. Separate mediation analyses were conducted to explore the degree that PTSD severity, blast mTBI severity, and impact mTBI severity influenced the association between subjective cognitive complaints and objective cognitive performance. Models reflecting significant mediation were followed by post-hoc moderated mediation analyses. RESULTS: Subjective cognitive complaints and objective cognitive performance were significantly associated (β [SE]= −6.49[2.85]; p=.03), but this relationship was mediated by PTSD severity (β [SE]= −2.95[2.86]; p=.30). PTSD mediation was not moderated by either blast or impact mTBI. CONCLUSION: The present results delineate the prominent impact of PTSD symptoms, relative to blast and impact mTBI, on cognition following combat. These findings highlight the importance of assessing for trauma-related psychopathology in those seeking neuropsychological assessment or rehabilitative care for cognitive complaints.

Mild Traumatic brain injury (mTBI) is a signature wound in military personnel, and repetitive mTBI has been linked to age‐related neurogenerative disorders that affect white matter (WM) in the brain. However, findings of injury to specific WM tracts have been variable and inconsistent. This may be due to the heterogeneity of mechanisms, etiology, and comorbid disorders related to mTBI. Non‐negative matrix factorization (NMF) is a data‐driven approach that detects covarying patterns (components) within high‐dimensional data. We applied NMF to diffusion imaging data from military Veterans with and without a self‐reported TBI history. NMF identified 12 independent components derived from fractional anisotropy (FA) in a large dataset (n = 1,475) gathered through the ENIGMA (Enhancing Neuroimaging Genetics through Meta‐Analysis) Military Brain Injury working group. Regressions were used to examine TBI‐ and mTBI‐related associations in NMF‐derived components while adjusting for age, sex, post‐traumatic stress disorder, depression, and data acquisition site/scanner. We found significantly stronger age‐dependent effects of lower FA in Veterans with TBI than Veterans without in four components (q < 0.05), which are spatially unconstrained by traditionally defined WM tracts. One component, occupying the most peripheral location, exhibited significantly stronger age‐dependent differences in Veterans with mTBI. We found NMF to be powerful and effective in detecting covarying patterns of FA associated with mTBI by applying standard parametric regression modeling. Our results highlight patterns of WM alteration that are differentially affected by TBI and mTBI in younger compared to older military Veterans.