A five-year study conducted by researchers at the National Institutes of Health (NIH) found no significant evidence of brain injury detectable by MRI scans in a group of U.S. government employees who experienced anomalous health incidents (AHIs), also known as “Havana Syndrome.” The study, published in the Journal of the American Medical Association (JAMA), compared the brain scans and clinical assessments of over 80 individuals who reported AHIs with those of healthy control participants.
AHIs, first reported by U.S. personnel in Havana, Cuba, involve symptoms such as hearing unusual noises, feeling head pressure, and experiencing headaches, dizziness, and cognitive issues. The NIH researchers used advanced imaging techniques and conducted thorough clinical evaluations to determine if there were any structural brain or biological differences between those who experienced AHIs and the control group.
“Our goal was to conduct thorough, objective and reproducible evaluations to see if we could identify structural brain or biological differences in people who reported AHIs,” said Leighton Chan, M.D., lead author on one of the papers. “While we did not identify significant differences in participants with AHIs, it’s important to acknowledge that these symptoms are very real, cause significant disruption in the lives of those affected and can be quite prolonged, disabling and difficult to treat.”
The study found no consistent set of imaging abnormalities that differentiated participants with AHIs from the control group. However, the researchers noted that the lack of MRI-detectable differences does not rule out the possibility that an adverse event impacting the brain occurred at the time of the AHI.
“It is possible that individuals with an AHI may be experiencing the results of an event that led to their symptoms, but the injury did not produce the long-term neuroimaging changes that are typically observed after severe trauma or stroke,” said Carlo Pierpaoli, M.D., Ph.D., lead author on the neuroimaging paper.
The study also found that participants with AHIs self-reported significantly higher levels of fatigue, post-traumatic stress, and depression compared to the control group. Additionally, 41% of the AHI group met the criteria for functional neurological disorders (FNDs) or had significant somatic symptoms.
“The post-traumatic stress and mood symptoms reported are not surprising given the ongoing concerns of many of the participants,” said Louis French, Psy.D., a co-investigator on the study. “Often these individuals have had significant disruption to their lives and continue to have concerns about their health and their future. This level of stress can have significant negative impacts on the recovery process.”
The researchers emphasized that while the study did not find clear evidence of brain injury, further research is needed to understand the cause of these debilitating symptoms and to develop effective treatments for those affected.
