US diplomats in Cuba who, in 2016, reported hearing loss, fogginess, and vertigo after hearing chirping sounds, suffered from concussion symptoms with no known cause, a new medical report concluded.
Last August, the first public reports of the injuries sparked fears of a sonic weapon attack in Havana. The long-awaited JAMA case report on 21 of the 24 affected diplomats by University of Pennsylvania researchers only rules out sonic attacks as an explanation for their symptoms — and finds scant evidence of brain damage in MRI images reported in early news accounts of the outbreak.
“If you didn’t know their history, they would look to you like other concussion patients,” the study’s lead author, Randel Swanson, told BuzzFeed News.
An array of balance, vision, and concentration problems were severe enough to require rehabilitation treatment in 18 of the 21 patients.
“It’s premature to call this a syndrome, but what we have is a constellation of symptoms,” Swanson said. Unlike normal concussions, many of the diplomats reported problems that popped up or worsened weeks after their initial injuries, he added.
“By and large, concussions get better or stay the same, they don’t do new things,” Swanson said.
All but two of those diplomats reported their symptoms started with hearing a high-pitched sound in Havana. All but one of the 21 reported other persistent problems that included headaches, hearing loss, and fatigue. The report throws cold water on the sonic weapon explanation for the symptoms, repeating past findings that inaudible sound waves can’t physically cause concussion symptoms.
And it reports that MRI images of the diplomats’ brains show only three displayed mild white matter changes — two mild and one moderate case — that were unusual for their ages. None of those brain changes looked tied to symptoms, and since the doctors didn’t have images of the diplomats' brains before their posting in Havana, they couldn’t say whether they were relevant.
An explanation for the symptoms, which led to the expulsion of Cuban diplomats from the US and a diplomatic tiff with Cuba, remained “elusive” despite the case report, neurologists Christopher Muth of Rush University Medical Center and Steven Lewis of the Lehigh Valley Health Network, wrote in a commentary accompanying the study. “Nonetheless, the similarities among the 21 cases merit consideration of a common medical, environmental or psychological event as the potential cause,” they conclude.
The authors found no sign of any tropical virus linked to neurological illness or poisoning, both alternative explanations offered by some observers for the incidents, or signs of head trauma. Muth and Lewis suggest even the comparison with concussion might be overstated, saying the symptoms also resemble novel dizziness syndromes triggered by everything from whiplash to migraines.
Citing medical privacy and national security restrictions related to the ongoing investigation of the injuries, the report lacks information on the sex and age of the diplomats.
Neuroimaging expert Arthur Toga of the Keck School of Medicine at the University of Southern California called the study “a bit descriptive and inconclusive,” in an email to BuzzFeed News, noting the MRI results don’t indicate anything grossly wrong with the diplomats’ brains that correspond to their symptoms.
The study authors ruled out a mass psychology event, or mass psychogenic illness (MPI), as an explanation, offered by the Cuban government in a recent report. They argued the diplomats showed no signs of “malingering” (exaggerating illness to avoid work) and want to return to diplomacy. Seven have returned to work and all are progressing with rehabilitation, Swanson said.
While malingering has nothing to do with psychogenic illness, psychologist James Pennebaker of the University of Texas told BuzzFeed News, the report does argue against that explanation by claiming some of the diplomats independently developed symptoms before they ever heard about them in others. “Based on the limited amount of information I have, I would have to agree that this was probably not a case of MPI,” Pennebaker said.
But a second expert in psychogenic illness outbreaks, medical sociologist Robert Bartholomew of Botany College in Auckland, New Zealand, said that’s still the most convincing explanation. “The findings in this new study are vague to say the least, and unconvincing at best,” he said by email. “I have little doubt that we are dealing with an episode of conversion disorder involving neurological symptoms commonly referred to as motor hysteria.”
Swanson said that as a concussion expert, the symptoms in the diplomats look unmistakably similar to mild or moderate brain injuries. “Clinically, it’s clear they have suffered some sort of neurological insult. Something happened.”
Dan Vergano is a science reporter for BuzzFeed News and is based in Washington, DC.
Contact Dan Vergano at firstname.lastname@example.org.
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