• Posted March 19, 2024

No Brain Injuries Seen Among 'Havana Syndrome' Patients

“Havana Syndrome” appears to cause real and severe symptoms among federal employees suffering from the mystery illness, but there's no evidence of brain injury or biological abnormalities among them, a new report shows.

Researchers evaluated 81 U.S. diplomats and other federal employees, mostly stationed abroad, who had complained of hearing noise and feeling head pressure just before experiencing headache, dizziness, trouble thinking and other symptoms.

These symptoms have been described as “Havana Syndrome” because U.S. government personnel stationed in Havana, Cuba, first reported such cases in 2016.

Since then, hundreds of American personnel in stations in many different countries have reported similar symptoms.

After nearly five years of research, investigators from the National Institutes of Health (NIH) found that MRI brain scans of Havana Syndrome patients did not appear significantly different than those taken of healthy patients in a control group.

A battery of other medical tests also found no differences between Havana Syndrome patients and healthy controls that would explain their symptoms. These included blood panels, hearing tests, balance tests, vision screening and psychological evaluation.

However, researchers hastened to add that these symptoms are genuine, even if a cause isn't apparent.

“While we did not identify significant differences in participants with [Havana Syndrome], 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,” said lead researcher Dr. Leighton Chan, chief of rehabilitation medicine and acting chief scientific officer at the NIH Clinical Center.

For example, Havana Syndrome patients self-reported significantly increased symptoms of fatigue, post-traumatic stress, anxiety and depression.

A little over 40% of the patients also met the criteria for functional neurological disorders, a group of common movement disorders caused by abnormalities in brain function, researchers said.

And most of the patients with functional neurological disorders also experienced a problem called persistent postural-perceptual dizziness, in which a person experiences dizziness or vertigo for no apparent reason.

“The post-traumatic stress and mood symptoms reported are not surprising, given the ongoing concerns of many of the participants,” said co-researcher Louis French, a neuropsychologist and deputy director of the National Intrepid Center of Excellence at Walter Reed National Military Medical Center.

“Often these individuals have had significant disruption to their lives and continue to have concerns about their health and their future,” French added in an NIH news release. “This level of stress can have significant negative impacts on the recovery process.”

If the symptoms were caused by some external phenomenon, it didn't leave any lasting mark on the patients, researchers concluded.

But it is possible that whatever markers associated with such a phenomenon might have faded or can't be detected, the team added.

The new research was published March 18 in the Journal of the American Medical Association.

More information

George Washington University has more on Havana Syndrome.

SOURCE: National Institutes of Health, news release, March 18, 2024