High cumulative blast exposure in military personnel is associated with worsening brain function and lower quality of life
This article was initially published in the 7/18/24 edition of our Concussion Update newsletter; please consider subscribing.
In a multimodal study published in Proceedings of the National Academy of Sciences, Natalie Gilmore et al. found that higher cumulative blast exposure was associated with decreased brain function and lower quality of life. According to a New York Times article, the damage seen in these brains was not CTE but a new pathology that shows that astrocytes, a type of cell essential to brain function, “had grown into gargantuan, tangled masses that barely functioned.” Furthermore, decreased connectivity and increased cortical thickness were found in specific brain regions, emphasizing the need for further research into this pathology.
During two days of intensive assessments, 30 active-duty Special Operations Forces participated in neuroimaging, blood tests, cognitive tests, and surveys of self-reported brain health to assess psychological health, cognitive ability, and brain structural integrity. The authors also collected self-reported data on repeated blast exposure (RBE) and any TBI history, performing statistical analyses to correlate the tested measures with RBE.
Cumulative high blast exposure was associated with decreased connectivity in the executive control network (responsible for complex reasoning and decision-making) and abnormal thickness in some brain areas. The abnormal thickness of the rostral anterior cingulate cortex (rAAC) may hinder cognition and modulation of emotion. This area of the brain relies on astrocyte cells for immune protection, and these cells have formed into tangles in the study participants. The astrocyte tangles hinder the role that the rAAC region plays in cognitive, emotional, and executive networks, as well as default processing. Default processing consists of automatic cognitive behaviors such as social cognition, mind-wandering, and memory recall.
Further research will improve the understanding of the pathology related to RBE and should strive to further our understanding of its mechanisms. The authors recognize that a limitation in this study is that there was no control group; further studies should keep this in mind. Implementing regulatory measures and increasing awareness of the impacts of repeated blast exposure within the US military may help reduce poor mental health and suicide. To learn more about the recent attention to blast-related TBI research and policy, check out Concussion Alliance’s recent blog posts on this issue here, here, and here.
