IRP studies find severe symptoms of 'Havana Syndrome,' but no evidence of MRI-detectable brain injury or biological abnormalities

Monday, March 18, 2024

Compared to healthy volunteers, affected U.S. government personnel did not exhibit differences that would explain symptoms

Using advanced imaging techniques and in-depth clinical assessments, a research team at the National Institutes of Health (NIH) found no significant evidence of MRI-detectable brain injury, nor differences in most clinical measures compared to controls, among a group of federal employees who experienced anomalous health incidents (AHIs). These incidents, including hearing noise and experiencing head pressure followed by headache, dizziness, cognitive dysfunction and other symptoms, have been described in the news media as 'Havana Syndrome' since U.S. government personnel stationed in Havana first reported the incidents. Scientists at the NIH Clinical Center conducted the research over the course of nearly five years and published their findings in two papers in JAMA today.

“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., chief, rehabilitation medicine and acting chief scientific officer, NIH Clinical Center, and 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.”

Researchers designed multiple methods to evaluate more than 80 U.S. government employees and their adult family members, mostly stationed abroad, who had reported an AHI and compared them to matched healthy controls. The control groups included healthy volunteers who had similar work assignments but did not report AHIs. In this study, participants underwent a battery of clinical, auditory, balance, visual, neuropsychological and blood biomarkers testing. In addition, they received different types of MRI scans aimed at investigating volume, structure and function of the brain.