Examinations of U.S. Embassy personnel who developed neurological symptoms in 2016 while stationed in Havana, Cuba, indicated that they really did sustain brain injuries, even though none of the individuals experienced head trauma, researchers reported in JAMA.
The embassy employees reported persistent cognitive, vestibular, and oculomotor problems plus sleep impairment and headaches after experiencing an intensely loud, unusual noise or sensation of unknown origin, according to Douglas Smith, MD, and colleagues at the University of Pennsylvania in Philadelphia.
The symptoms resemble mild brain traumatic injury, or concussion, they reported in JAMA. It is unclear if or how the noise is related to the symptoms, and the report shed no light on what else might have caused the symptoms. Some have speculated that the embassy personnel were attacked with an acoustic weapon beamed from outside the embassy.
“These patients are having problems with working memory, sustained attention, and concentration,” co-author Randel Swanson II, DO, PhD, said in an accompanying podcast interview. Like concussion patients, work takes more energy for these people because they lack cognitive reserve. “Something’s happened to the network and it takes them so much more energy so they’re fatigued and by the end of the day, they have massive headaches,” he said.
“This is really concussion without concussion,” Smith added.
In late 2016, U.S. government personnel in Havana reported various neurological symptoms after experiencing strange sounds, described mostly as loud and high pitched, that were associated with a sensation described as pressure-like or vibratory. Initial symptoms appeared to be auditory related and led to a triage program centered on otolaryngology evaluations for embassy community members at the University of Miami. Sixteen individuals who heard the sound presented neurological signs and symptoms that resembled a concussion. Over time, eight additional people reported similar problems.
In July 2017, the U.S. Department of State convened an expert panel which concluded that the triage findings most likely were related to neurotrauma from a non-natural source and recommended further study at the University of Pennsylvania Center for Brain Injury.
Of 24 individuals with suspected exposure to the noise or sensation, 21 completed multidisciplinary evaluation an average of 203 days later. The group included 10 men (average age 39) and 11 women (average age 47).
Nearly all — 20 of 21 people, or 95% — reported immediate neurological symptoms associated with the noise. One individual woke from sleep with acute symptoms including headache, unilateral ear pain, and hearing changes, but did not experience the phenomena.
Twenty embassy personnel reported persistent symptoms — ones that lasted for more than 3 months — that included cognitive (81%), balance (71%), and auditory (68%) problems, sleep impairment (86%), and headaches (76%).
Objective findings included cognitive (76%), vestibular (81%), and oculomotor (71%) abnormalities, the researchers noted. Three individuals experienced moderate to severe sensorineural hearing loss. Fifteen people (71%) required medication for sleep dysfunction and 12 (57%) for headache. Fourteen people stopped working; seven eventually returned to work with restrictions, home exercise programs, and cognitive rehabilitation. All 21 patients had MRI neuroimaging and most had conventional findings within normal limits.
Several important factors need to be considered in this case series, observed Christopher Muth, MD, of Rush University Medical Center in Chicago, and Steven Lewis, MD, of Lehigh Valley Health Network in Allentown, Pennsylvania, in an accompanying editorial.
While the embassy employees were in a common geographic area when their symptoms first appeared, not everyone had the same symptoms. It’s unclear whether individuals who developed symptoms later knew about previous reports, they noted.
“Furthermore, the quantitative results for specific tests (e.g., neuropsychological tests) are not yet available for all affected patients, so independent assessment as to the scope and severity of deficits among all individuals remains challenging,” they wrote.
And the analogy to concussion may be not be quite right because many of the symptoms described also occur in conditions like persistent postural-perceptual dizziness (PPPD), they noted, although “PPPD alone does not appear to explain the entirety of the symptoms reported nor the clustering of individuals affected.”
The symptoms have raised outside concerns about delusional disorders or mass psychogenic illness. But several of the manifestations in this group of patients — including the oculomotor and vestibular testing abnormalities — could not have been manipulated, the researchers maintained.
“Furthermore, mass psychogenic illness is often associated with transient, benign symptoms with rapid onset and recovery often beginning with older individuals,” they wrote. “In contrast, the Havana cohort experienced persisting disability of a significant nature and are broadly distributed in age.”
“Rather than seeking time away from the workplace, the patients were largely determined to continue to work or return to full duty, even when encouraged by healthcare professionals to take sick leave,” they added.
The researchers plan further neuroimaging to evaluate the embassy employees. “Since the clinical features appear so similar to concussion, we will use diffusion tensor imaging and advanced MRI that examines the connectivity of the brain’s network,” Smith told MedPage Today. “This is commonly shown disrupted in concussion. However, if we do find changes, we anticipate that the distribution will be different than in concussion, where some findings are related to head impact.”
In the meantime, the State Department issued a level 3 travel advisory to Cuba, recommending that Americans reconsider trips there due to “health attacks directed at U.S. Embassy Havana employees.”
The authors and editorialists reported no disclosures.