The “sonic attack” in Cuba and China… definitely did something to diplomats’ brains. Literally.

The New York Times reports on findings (from JAMA) that the people who’d complained of nausea, visual blurring and other effects after some strange events in America’s Cuban and Chinese embassies show signs of physical changes to their brains:

Now, researchers are reporting results from the first brain-imaging studies of 40 of those diplomats, who were carefully examined by neurologists after returning home from Cuba. The study, appearing on Tuesday in the medical journal JAMA, concludes that the diplomats experienced some kind of brain trauma. But the nature and cause of that trauma were not clear, as it did not resemble the signature of more familiar brain injuries such as repeated concussions or exposure to battlefield blasts.

“The main thing we can do with brain imaging is ask whether something happened to the brain,” said Ragini Verma, a professor of radiology at the University of Pennsylvania Perlman School of Medicine and the lead author of the new report. “And the answer we found is that yes, it did.”

The new study was an extension of examinations, conducted at the University of Pennsylvania Center for Brain Injury and Repair, of several dozen diplomats returning from Cuba. In 2018, the Penn team, which included Dr. Douglas Smith and Dr. Randel Swanson, reported on the first 21 of those patients, and identified a range of peculiar and often shared symptoms.

“The unique circumstances of these patients, and the consistency of the clinical manifestations, raised concern for a novel mechanism of a possible acquired brain injury,” that report concluded.

In the new study, the research team focused on those 21 patients and 19 subsequent ones, examining brain areas known to support hearing, balance and motor control. It also measured each individual’s volume of gray matter, the overall population of neurons, and of white matter, the connective tissue between the neurons. Gray matter makes up the bulk of the brain’s distinct organs, specialized to manage functions like vision, hearing and movement. White matter comprises the wiring that connects cells and organs into wider circuits. Sharp deficits in either can compromise brain function.

Those measures were then compared to an identical battery of brain images from 48 healthy adults representing the same mix of ages, genders and educational attainment.

On average, the diplomats had a lower volume of white matter than individuals in the control group. They also showed clear differences in the volume, connectivity and tissue properties of the cerebellum, which is involved in maintaining balance, and lower connectivity among neurons in the auditory and visual-spatial areas of the brain. The analysis found no difference between the groups in so-called executive-control networks, which are involved in thinking and planning.

The researchers could not say for certain what these differences mean, except that they are consistent with the symptoms the diplomats have reported. The overall pattern was unlike anything found in studies of people with traumatic brain injuries, multiple sclerosis, stroke damage or other neural disorders.

You can read the new JAMA study here, and the earlier UPenn research here. [Via Nature Briefing]