In late 2016, U.S. and Canadian diplomats at their embassy in Havana, Cuba began coming down with unexplained symptoms, including nausea, headaches, and hearing loss. Some also claimed to have heard mysterious sounds just prior to their symptoms, fueling a theory by some U.S. officials and the media that a “sonic weapon” aimed at the diplomats could have been to blame. Yet no concrete evidence of any potential physical cause for their symptoms has emerged, let alone a sonic or microwave weapon.
Today, researchers at the University of Pennsylvania say they’ve found signs of brain differences in many of the affected diplomats they’ve examined. They’ve even gone as far as to speculate these differences could mean the diplomats were injured in a way never seen before. But other scientists are deeply skeptical of the team’s interpretations of their research, and argue they haven’t found anything meaningful.
The University of Pennsylvania team was tasked by the U.S. government back in 2016 to examine and scan the brains of diplomats and their family members who said they had been afflicted by what’s often referred to as “Havana syndrome.” Last year, they published the preliminary results of their work—involving 21 patients—in the journal JAMA. Their new study, also published in JAMA, now includes 40 affected people. These patients were compared to a group of 48 healthy patients, matched up by age and other characteristics.
The authors said they used advanced brain-imaging techniques on both groups. Compared to the control group on average, they found the Havana patients had distinct differences in brain volume in certain regions of the brain, most notably the cerebellum, which helps coordinate our voluntary motor control, like walking and balancing. There was also evidence of impaired connectivity between neurons in subnetworks of the brain linked to vision and hearing.
According to the authors, the findings could explain some of the diplomats’ symptoms, such as their lack of balance and trouble with vision. And because their brains don’t look like the brains of people affected by known conditions like traumatic brain injury or concussion, they added, something unique might have happened to them.
“These findings may represent something not seen before,” said study co-author Douglas H. Smith, a neurosurgeon and director of UPenn’s Center for Brain Injury and Repair, in a release from the university.
But outside experts Gizmodo spoke to vehemently disagree.
“The study confirms there is no evidence of traumatic brain injury,” R. Douglas Fields, a neuroscientist who has independently investigated the cases (including traveling to Cuba himself and talking to fellow neurologists there), told Gizmodo by phone.
One major problem with the team’s research, Fields said, is that the tests used on the patients, while important for research, are not meant to find disease.
“These are not medical imaging methods—they’re not diagnostic,” he noted. “They don’t show pathology.”
For example, doctors might typically look for lesions on a standard CT scan to diagnose brain disease or injury, but the researchers in the current study didn’t find that. The tests they relied on, such as advanced diffusion MRI, instead look for microscopic changes in the structure or volume of the brain. But we don’t know whether these changes are actually harmful, or responsible for the patients’ symptoms. And these tests aren’t designed for that purpose. They’re often used to better understand the brains of people already diagnosed with diseases like schizophrenia.
Importantly, and as the authors admit in the study, the “clinical importance of these differences” in the brain is uncertain. And though there might be small differences in the brains of Havana patients compared to the general population, there could be many reasons for these differences.
Even calling what they have a “syndrome” is misleading, Fields said, because syndromes are meant to be a checklist of shared symptoms and signs often seen together (even if their cause is unclear, as is the case with chronic fatigue syndrome). Yet the Havana patients have reported a wide range and severity of symptoms, many of which are seen in some but not others. And a lot of these symptoms, like trouble sleeping, can be explained by many other things.
The sonic weapon theory has received its share of debunking elsewhere. This January, researchers reported their findings looking into the purported recording of damaging sounds heard by one of the patients that was released by the AP in 2017. They made a convincing case that it was nothing more than the intense but very normal chirping of crickets commonly found on the island.
To be clear, Fields and other skeptics aren’t claiming that the Havana patients are making up their illness. For some, there may very well be a shared, unremarkable physical cause. Twelve of the patients studied by the UPenn team, for instance, had a history of prior concussion, which could possibly explain some people’s brain readings and lingering symptoms. Some Havana patients were also excluded by the team for a history of severe brain injury. But even if they weren’t included in the study, those injuries could obviously still be a contributing factor for their experiences. For the rest, it could be a hodgepodge of other ailments, none of which require the invention of a sonic weapon that might not even be theoretically possible.
And some say the symptoms could be a physical manifestation of stress and anxiety that spread among people understandably worried at seeing their friends and families becoming sick—a condition commonly known as conversion disorder. The diagnosis is itself often controversial, since no one likes to be told their symptoms could be a product of their mind. But there’s nothing inherently shameful about the disorder, nor are people’s symptoms any less “real.”
“I highly respect the undesirable situation the diplomats found themselves [in]. They obviously suffered, their complaints should be considered very seriously, and possibly treated,” Sergio Della Sala, a professor of cognitive neurology at the University of Edinburgh in the UK, told Gizmodo via email. “This is... different from claiming the discovery of a new syndrome, let alone caused by yet to-be-demonstrated nasty sounds.”
Fields doesn’t discount the possibility that something else might turn up that could prove these cases are caused by something more extraordinary. But he disagrees with the rampant theorizing by certain members of the media, scientists, and the U.S. government in studying and reporting these cases. Government officials even pulled diplomats from China in 2017 and 2018, claiming they had experienced something “very similar” to the Havana cases.
“The problem with this story all along is in separating speculation from fact. As a scientist you have to look for and comment on the facts. And the facts provide no evidence that there was an injury of any kind; that there was an attack or weapon. So far, there’s nothing to indicate any such thing,” Fields said.