Beginning in late 2016, U.S. diplomats and family members stationed in Havana, Cuba, reported a number of sudden-onset symptoms, including dizziness, ear pain and tinnitus. They noted a high frequency, loud and very localized sound that sometimes followed them as they moved through a room. For the first time, researchers from the University of Pittsburgh School of Medicine and the University of Miami Miller School of Medicine have described these acute symptoms and their associated clinical findings. The analysis is published today in the journal Laryngoscope Investigative Otolaryngology.
"This report is incredibly important because it represents the findings from patient evaluations that were conducted shortly after exposure, and an analysis of the data confirming that they had a unique set of symptoms that we have not seen before," said Carey Balaban, Ph.D., one of the corresponding authors on the study and a professor of otolaryngology in Pitt's School of Medicine who also has appointments in the departments of Neurobiology, Communication Science & Disorders, and Bioengineering at Pitt.
The study included a retrospective review of clinical data from 25 people at the U.S. Embassy who reported a localized sensation of noise and pressure, and 10 individuals who were housemates of those affected and did not experience the sensations.
"Objective testing showed evidence of a balance dysfunction that affects the inner ear and a unique pattern of cognitive dysfunction," said Michael E. Hoffer, M.D., professor of otolaryngology and neurological surgery at Miami's Miller School of Medicine and the lead and co-corresponding author. "This cluster of auditory, vestibular and neurological symptoms, along with associated psychological issues, does not resemble more classic traumatic brain injury (TBI), based on our team's vast experience in this area."
Over the course of a few months beginning in February 2017, Hoffer, along with University of Miami's Hillary Snapp, Au.D., Ph.D., associate professor of otolaryngology and chief of audiology; Bonnie E. Levin, Ph.D., professor of neurology and director of the Division of Neuropsychology; and James Buskirk, a doctoral student and physical therapist, evaluated individuals who suspected they had been affected, between four and 60 days after exposure. The team also evaluated a larger group of 105 embassy workers who denied any "exposure" to noise or a pressure sensation.
Balaban, who has collaborated with Hoffer for more than two decades on research involving balance disorders and traumatic brain injuries, was called in to join the team because of his longstanding experience in studying complex and often difficult-to-understand symptoms involving balance disorders. Balaban has published extensively on inner ear physiology, including seminal research that has shown a link between balance disorders and cognitive dysfunction, anxiety and migraine.
The study found that all of the 25 people with symptoms noticed unsteadiness and features of cognitive impairment. Dizziness (92 percent) and cognitive complaints (56 percent) were the most common symptoms. Formal testing revealed that all of them had an inner ear abnormality and evidence of cognitive dysfunction. After the evaluations, a number of the patients were treated for balance, cognitive and emotional symptoms.
"This is the first and only report of the acute presentation seen shortly after exposure in this unique group of patients," said Hoffer. "Our findings are unaffected by the influence of time, variable amounts of rehabilitation, workers compensation concerns or media attention. It is an important contribution to this field and in helping us to determine what happened."
While the study did not attempt to determine the cause of the symptoms in these U.S. Embassy residents, the researchers noted that intense ultrasonic exposures can produce "a syndrome involving manifestations of nausea, headache, tinnitus, pain, dizziness and fatigue," based on occupational health literature. "The exposure responsible for these findings is unknown," they wrote. "It would be imprudent to exclude any potential directed or non-directed energy sources at this time."
No funding was provided for this work.