A US government research team found no significant evidence of brain injury among a group of federal employees who reported symptoms of “Havana syndrome” that emerged in 2016, according to studies published in a medical journal on Monday.
Researchers at the National Institutes of Health (NIH) also found There are no differences in most clinical measures. between a group of 86 employees and their adult family members who reported unusual health incidents and a matching group of healthy volunteers who had similar work assignments.
Symptoms of the mysterious ailment, first reported by U.S. embassy officials in Havana, Cuba’s capital, and later afflicting diplomats, spies and other personnel around the world, include hearing noises and experiencing pressure in the head. , followed by headache, migraines, dizziness and memory lapses.
“These individuals have symptoms that are real, distressing, and very difficult to treat,” Dr. Leighton Chan, acting scientific director of the NIH Clinical Center and senior author of the study, said on a call to discuss the findings published in JAMA.
Study participants, including personnel who had been stationed in Cuba, China, Vienna and the United States, underwent a series of clinical, hearing, balance, visual, neuropsychological and blood tests. They also received different types of MRI scans aimed at investigating brain volume, structure and function.
The findings, from two studies conducted between 2018 and 2022, do not match the results of a different study conducted at the University of Pennsylvania and published in JAMA in 2019, which showed some subtle brain changes in those affected.
Chan said the NIH used more rigorous MRI protocols and a more similar control group in terms of work activities and location. She said the studies could not rule out the possibility that an external event caused the patient’s symptoms.
An accompanying JAMA editorial by Dr. David Relman, a professor at Stanford University School of Medicine, noted that previous studies concluded that some of the cases could plausibly be explained by exposure to radiofrequency energy.
It suggested the need for surveillance systems designed to quickly detect early cases of the syndrome and clusters of concern across multiple US government agencies and departments.
Chan said such an approach could end up causing more worry and distress, negatively affecting people’s health.
NIH researchers found that more than a quarter of patients who reported symptoms developed a chronic condition called persistent postural-perceptual dizziness. They also reported a significant increase in symptoms of fatigue, post-traumatic stress and depression, compared to the control group.
The findings from the MRI brain imaging study “should reassure patients” as researchers found no link between unusual symptoms and neurodegenerative changes, said Louis French, a study investigator and deputy director of the Intrepid National Center of Excellence at Walter Reed. National Military Medical Center.
“The reported post-traumatic stress and mood symptoms are not surprising given the current concerns of many of the participants,” he said.
Last year, US intelligence agencies concluded that it was “very unlikely” that a foreign adversary was responsible for the Havana syndrome cases.
The agencies suggested in that report that the symptoms reported by the US personnel were likely the result of pre-existing conditions, conventional illnesses and environmental factors.
“I don’t think there’s anything in our study that contradicts that,” said the NIH’s Chan.