Mild Traumatic Brain Injury from Primary Blast vs. Blunt Forces: Post-Concussion Consequences and Functional Neuroimaging (P01.178)

Abstract

Objective: This study investigated changes in functional health and well-being, cognition, and functional neuroimaging among Iraq/Afghanistan veterans who sustained pure blast-force mild traumatic brain injury (mTBI), as compared to those who sustained pure blunt-force mTBI. The aim was to document post-concussion consequences and associated changes in cerebral metabolism from mTBI due to blast forces. Background Injuries from blast forces are a hallmark of the conflicts in Iraq and Afghanistan and may cause undetected neurological dysfunction from mTBI. The effects of primary blast overpressure on the brain have been difficult to clarify because of complications, such as secondary and tertiary blast effects and comorbid post-traumatic stress disorder (PTSD). Design/Methods: Inclusion criteria included presence of pure blast or blunt injury, absence of PTSD, and between 6-36 months post-trauma. The Blast Group (n=12) and the Blunt Group (n=12) underwent assessments of well-being, cognition, and resting fluorodeoxyglucose positron emission tomography (PET). Results: There were no group differences on mTBI-related variables, the Rivermead Post-Concussion Questionnaire (RPQ), or the SF36-V Health Survey. Both groups, however, did worse than published norms on the RPQ and SF36-V, and the Blast Group had additional worse SF36-V subscale scores on Bodily Pain and Social Functioning. Compared to the Blunt Group, the Blast Group had poorer scores on the Paced Auditory Serial Addition Test (PASAT) and greater PET hypometabolism in the right superior parietal region. Only the Blast Group had significant correlations of their RPQ, SF36-V Mental Composite Score, and PASAT scores with specific regional metabolic changes. Conclusions: Together these results suggest that pure blast force mTBI has post-concussion consequences. Blast mTBI may cause deficits in well-being, possibly from an altered bodily self-image, and in attentional control. These changes are associated with regional changes in cerebral metabolism, particularly hypometabolism in the right hemisphere. Supported by: Department of Veteran9s Affairs Grant. Disclosure: Dr. Mendez has nothing to disclose. Dr. Licht has nothing to disclose. Dr. Berenji has nothing to disclose. Dr. Peppers has nothing to disclose.