Extensive examinations of people claiming to have Havana syndrome, an unexplained disorder that has affected dozens of American diplomats and embassy employees, have not revealed significant brain damage, according to a study by a research agency. American health.
The study, conducted by researchers at the National Institutes of Health (NIH) and published Monday in the journal JAMA, involved 81 patients who experienced "abnormal health incidents", according to the terminology used in the United States. .
These disorders (migraines, dizziness, nausea, vision problems, etc.) first struck American and Canadian diplomats stationed in Cuba in 2016, hence its name “Havana syndrome”.
They were then reported elsewhere in the world (China, Germany, Australia, Russia, Austria) and even in Washington.
NIH researchers sought to identify brain lesions by comparing MRI results between patients claiming to have the syndrome and a control group.
The study “revealed no notable difference (…) in brain structure or function” between individuals in the two groups, they emphasize.
In another NIH study, also published Monday in JAMA, researchers attempted to identify differences in biological markers between affected people and a control group.
Without revealing “notable differences” there either, “with the exception of objective and self-reported assessments of imbalance and symptoms of fatigue, post-traumatic stress, and depression”.
Speculation on origins
Both studies, however, were criticized in an editorial also published by JAMA on Monday and written by David Relman, a microbiologist at Stanford Medical School.
According to this researcher, who has worked on the issue of these “abnormal health incidents”, “while the NIH study used advanced brain imaging techniques, current MRI technology is potentially insensitive, or poorly calibrated” for certain characteristics of these disorders.
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For Leighton Chan, lead author of one of the two studies and cited in an NIH press release, despite these results “it is important to recognize that these symptoms do exist, cause significant disruption in the lives of those who experience them. affected, and can be quite long-lasting, debilitating, and difficult to treat.”
The “Havana syndrome” affair had from the start led to widespread speculation about its origin.
Some U.S. officials initially downplayed symptoms sometimes attributed to stress, with others privately speaking of possible attacks and suspecting countries like Russia.
But American intelligence estimated in March 2023 “very unlikely” that a foreign power or a weapon was at the origin of the mysterious disorder.