Study Looks into Ear-Related Symptoms Experienced by American Diplomates in Cuba

It’s vexing for people all over the world that people can be harmed and not know why,” said Michael E. Hoffer, MD, professor of otolaryngology and neurological surgery at the University of Miami Miller School of Medicine in Florida.

Speaking at a press conference held on December 12 at the University of Miami, Dr. Hoffer and coinvestigators shared with the press for the first time the results of a study they recently published on the presenting acute symptoms of the 25 American diplomates and family members who reported ear-related and neurological symptoms following exposure to an as yet unknown source while serving in their embassy roles in Havana starting in 2016 (Laryngoscope Inv Otol. Published December 12, 2018. doi: 10.1002/lio2.231).

The study represents the first step in understanding what remains a mysterious, and in Dr. Hoffer’s word “vexing,” event. Dr. Hoffer highlighted the particular importance of the study as the first of its kind to evaluate the patients in the acute phase of their injury, unaffected by variables that can alter people’s symptoms, such as longer duration of time from injury, treatments for symptoms, worker’s compensation issues, and media coverage. “This is the first and only report of the individuals seen acutely, shortly after the injury,” he said. “It’s the only study that is going to come out as the first naïve report of this condition.”

(A study published in JAMA documents evidence of neurological manifestations of these patients months after the injury, and therefore provides different information than that gathered by Dr. Hoffer and colleagues who report on the acute injuries [JAMA. 2018;319:1125–1133]).

Cause Vague, Symptoms Specific

Dr. Hoffer emphasized that the study and its results focus on the presenting symptoms of the individuals he and his colleagues saw at the University of Miami Miller School of Medicine. Questions of cause were outside the scope of the study.

In the study, Dr. Hoffer and colleagues retrospectively report on the subjective and objective symptoms of 25 individuals who reported symptoms after experiencing a localized sensation of noise/pressure while in Havana beginning in 2016 and continuing into 2017, as well as 10 individuals (roommates of those with symptoms) without symptoms. Most of the symptomatic individuals reported intense ear pain and tinnitus immediately following the exposure. The most common complaints described by the symptomatic individuals were dizziness and disorientation, with some also reporting concerns about hearing loss.

The 35 individuals were sent to Dr. Hoffer and his colleagues for examination shortly after experiencing the noise or pressure and underwent a comprehensive history and physical examination.

We’re not saying that it’s not an injury of the brain; it may be. We do know for sure that it is an injury to the ear and that the brain is affected. —Michael E. Hoffer, MD

On physical examination, most (95%) of the symptomatic individuals reported dizziness, and approximately half (56%) had cognitive complaints. The most common complaints described dizziness and disorientation and being in what is called a “cognitive fog,” in which something feels off.

No subjective or objective otolaryngologic or neurologic findings of this nature were found in the 10 people without symptoms, who were in the same house when the symptomatic person was exposed.

Upon further testing and evaluation, these subjective symptoms were validated by auditory and neurological tests that confirmed that the 25 symptomatic individuals had specific symptoms related to vestibular disturbance and cognitive dysfunction. Symptoms included:

• Unsteadiness (or loss of balance and disorientation);
• Cognitive dysfunction characterized as decreased clarity of thought (“cognitive fog”); and
• Difficulty with emotional regulation, including increased anxiety and irritability.

Bonnie E. Levin, PhD, director of the division of neuropsychology and Bernard and Andrea Schoninger Professor of Neurology at the University of Miami Miller School of Medicine and coauthor of the study, talked at the press conference about how this constellation of symptoms (vestibular, cognitive, and emotional) cluster together. “My assessment of these individuals was that these symptoms were not random, were not isolated, and they actually fit together as a constellation of symptoms. Their subjective complaints were confirmed by objective neuropsychological testing showing a constellation of behavioral, emotional, and cognitive dysfunction,” she said, adding that this cluster is found to be related to vestibular damage and dysfunction in animal and human studies. Dr. Levin listed a number of specific symptoms validated by neurological testing (see “Neurological Symptoms Confirmed by Objective Tests,” below).

“We don’t know the exact source, but we do know that there is a common anatomic pathway that underlies this particular constellation of events, which involve vestibular, cognitive, and emotional change,” she said.

What the study did not find, contrary to some reports in the media, was that symptomatic patients had hearing loss. Auditory assessment in most patients did not show hearing loss, except in two persons who had prior hearing loss.

Also contrary to some reports in the media, the injuries sustained were not like traumatic brain injuries, said Dr. Hoffer. “We’re not saying that it’s not an injury of the brain; it may be,” he said. “We do know for sure that it is an injury to the ear and that the brain is affected.”

The outstanding question, he said, is whether the brain was affected directly or from the ear. “We don’t know and haven’t determined that yet,” he said.

Not Mass Hysteria

“What I think [it] is important that we show in this study is that we can have measurable, quantifiable evidence that something really happened,” said coauthor Carey D. Balaban, PhD, professor of otolaryngology, neurobiology, communication science and disorders, and bioengineering at the University of Pittsburgh School of Medicine. “It is not just hysteria.” He and his colleagues view this paper as a first important step in offering demonstrable criteria with well-established tests to distinguish people who present with the same exposure from those who present with something different.

“That first step is the first clue we have to go on toward figuring out what sort of cause might there be for this so we can understand and control, mitigate, diagnose, and treat people properly,” he said.

He emphasized that no inferences can be drawn from this study as to what the cause may be.

He believes, however, that better understanding the cause should be an area of active research. As such, he is currently involved in research sponsored by the Office of Naval Research to get an idea of what the possibilities may be. “We’re not ready to rule anything out yet, but we want to find evidence to start ruling things out,” he said. “We have no favorite cause.” 

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Mary Beth Nierengarten is a freelance medical writer based in Minnesota.