A four year study using MRI-machines found no detectable difference in the brains of 81 people who claimed to be victims of "Havana Syndrome" and people in similar jobs who were healthy. Havana Syndrome is the name given to an odd series of events that began among US State Department employees in Havana, Cuba back in 2016. 

Those who experienced it often described a loud noise and a feeling of pressure in their heads which some described as directional. There were lots of reports about it followed by speculation that one of our adversaries, likely Russia, had created some new kind of energy weapon and was using it on US personnel. Alternatively, some suggested that Havana Syndrome could be the unexpected result of some kind of surveillance effort, i.e. not a weapon per se.

As time went on more and more employees claimed to be victims, including some in China and even some in Washington, DC. But the evidence that such a weapon existed seemed elusive. The intelligence community, which now refers to these as anonymous health incidents (AHIs), concluded a year ago that there was no energy weapon behind the reports. 

The current study began in 2018 and continued until 2022. The results were published today as two papers in the medical journal JAMA.

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.”...

For the imaging portion of the study, participants underwent MRI scans an average of 80 days following symptom onset, although some participants had an MRI as soon as 14 days after reporting an AHI. Using thorough and robust methodology, which resulted in highly reproducible MRI metrics, the researchers were unable to identify a consistent set of imaging abnormalities that might differentiate participants with AHIs from controls.

Despite the lack of evidence of brain damage, the authors of the study said the patients do have symptoms which in about a third of cases are preventing them from working.

The researchers emphasized that the patients who volunteered for the study, which began in 2018, do have severe symptoms that can be debilitating.

“These symptoms are real, and they feel it, and we acknowledge it,” said Leighton Chan, lead author of one of the papers. “We have a third of our cases that either are not working or are struggling to work.”

It certainly sounds like the researchers are saying the symptoms are psychosomatic but they are doing so as sensitively as possible. Nevertheless, the new study does contradict the findings of previous studies which suggested a very different conclusion.

“When we tested cognitive function, we didn’t see those deficits,” said neuropsychologist Louis French, deputy director of the National Intrepid Center of Excellence at Walter Reed National Military Medical Center and a co-investigator on the study. “What you’re seeing in some cases here are people that, for various reasons, have ongoing symptoms they’re reporting that just don’t play out when we’re looking at this objectively.”...

In a sign that the research has yet to resolve the issue, JAMA also published an editorial by Stanford University professor of medicine David Relman, who led two previous studies that said the AHIs “could be plausibly explained by exposure to directed, pulsed radio-frequency energy.”

Here's a sample of David Relman's response to the studies released today.

With few differences between cases and controls in the 2 current studies, one might suspect that nothing or nothing serious happened with these cases. This would be ill-advised. Two detailed investigations of AHIs (in which I played a role) found the cases with abrupt-onset, location-dependent sensory phenomena to be unlike any disorder reported in the neurological or general medical literature, and potentially caused by an external mechanism.6-9 The first of these investigations was undertaken by the US National Academy of Sciences in 2019-2020 and the second by a panel of experts on behalf of the US Intelligence Community in 2021-2022. The latter is described in more detail below. Both of these investigations involved experienced clinicians, detailed interviews with many affected individuals, careful reviews of the literature, and informal reviews of some medical records, but not physical examinations or directed testing. After considering a wide variety of possible mechanisms, both studies concluded that some of the cases with abrupt-onset, location-dependent sensory phenomena could be plausibly explained by exposure to directed, pulsed radiofrequency energy, despite important uncertainties. Others have also pointed to pulsed radiofrequency energy as a plausible mechanism.10,11 The US Intelligence Community has discounted this possibility and concluded that reported symptoms were probably the result of “preexisting conditions, conventional illnesses, and environmental factors,” influenced by their assessment that no foreign adversary played a role in these cases.12 While many cases may be explained in this fashion, the evidence that might favor known conditions, illnesses, and factors in some of the cases with abrupt-onset, location-dependent auditory-vestibular phenomena is weak at best.

Relman goes on to compare AHIs to other long term issues such as Gulf-War syndrome, long COVID and chronic fatigue syndrome, suggesting that the medical community as a whole is not good at dealing with certain types of issues. He recommends continued investigation of " pulsed forms of electromagnetic and acoustic energy."

But there is now a study showing no objective basis for AHI symptoms. So my guess is that this is the government's last word on Havana Syndrome.