Mild traumatic brain injury from primary blast vs. blunt forces: Post-concussion consequences and functional neuroimaging

INTRODUCTION: Primary blast forces may cause dysfunction from mild traumatic brain injury (mTBI). OBJECTIVE: To investigate the effects of primary blast forces, independent of associated blunt trauma and post-traumatic stress disorder, on sensitive post-concussive measures. METHODS: This study investigated post-concussive symptoms, functional health and well-being, cognition, and positron emission tomography (PET) neuroimaging among 12 Iraq or Afghanistanwar veterans who sustained pure blast-force mTBI, compared to 12 who sustained pure blunt-force mTBI. RESULTS: Both groups had significantly lower scores than published norms on the Rivermead Post-Concussion Questionnaire (RPQ) and the SF36-V Health Survey. 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. CONCLUSION: This pilot study suggests that pure blast force mTBI may have greater post-concussive sequelae including deficits in attentional control and regional brain metabolism, compared to blunt mTBI. A disturbance of a right parietal-frontal attentional network is one potential explanation for these findings.