Neuroimaging findings in US government personnel and their family members involved in anomalous health incidents
Abstract
Overview
US government personnel stationed internationally have reported experiencing anomalous health incidents (AHIs), with some individuals developing persistent and debilitating symptoms. The objective of this study was to assess whether quantitative magnetic resonance imaging (MRI) metrics could detect potential brain lesions in individuals with AHIs compared to a well-matched control group.
Design and Methods
- This exploratory study was conducted at the NIH Clinical Center and the NIH MRI Research Facility between June 2018 and November 2022.
- Participants: 81 individuals with AHIs and 48 age- and sex-matched controls, 29 of whom shared similar employment as the AHI group.
- Participants underwent comprehensive clinical, volumetric, and functional MRI assessments.
- High-quality diffusion MRI and additional volumetric scans were conducted during different sessions to ensure high reproducibility.
Findings
- No significant differences in any MRI metrics—including volumetric, diffusion, or functional connectivity—were detected between AHI participants and controls after adjustment for multiple comparisons.
- MRI data were highly reproducible and stable over time, with most participants showing <1% variation across repeat scans, indicating the absence of evolving brain lesions.
- At an unadjusted threshold (P < .05), participants with AHIs exhibited subtle differences, such as lower intranetwork connectivity within the salience networks and slight changes in the corpus callosum and selected white matter tracts; however, these findings did not remain significant after multiple comparisons adjustment.
- The relationship between imaging findings and clinical symptoms was weak (median Spearman ρ = 0.10).
- This study did not replicate earlier published findings linking AHIs and distinct MRI abnormalities.
Conclusion
There was no significant MRI-detectable evidence of brain injury among individuals reporting anomalous health incidents when compared to well-matched controls. These findings are important for guiding future research and inform clinical care strategies for affected individuals.