For nearly a year, between late 2016 and August 2017, several U.S. government personnel serving on diplomatic assignment in Havana, Cuba, reported unusual symptoms associated with exposure to a mysterious auditory phenomenon. Hearing Watch covered the initial reports here:
At the time, reputable news outlets reported either infrasound (sound below 20 Hz) or ultrasound (sound above 20,000 Hz) to be the most likely explanation of these odd symptoms, but speculation centered primarily on infrasound as the culprit.
In a February 15th JAMA article, physicians at the University of Pennsylvania School of Medicine reported results of a retrospective assessment of several individuals who experienced the symptoms while stationed in Cuba in 2016 and 2017.
Medical Symptoms from “Sonic Attack”
Immediate symptoms included headache, ear pain, and hearing loss. Several days after exposure to the sound, individuals reported they experienced additional cognitive and physical symptoms, plus changes in their mood. Many of the individuals continued to experience the symptoms for more than three months following the exposure.
Twenty-four individuals were referred by the US Department of State to the University of Pennsylvania for evaluation with 21 of the 24 individuals undergoing a comprehensive medical assessment, including cognitive, vestibular, oculomotor and auditory evaluation conducted by a multi-disciplinary team. In addition, MRI imaging evaluations were conducted. The mean age of the 21 individuals was 43 years, and comprised of 11 women and 10 men. On average, the comprehensive evaluation was conducted 203 days after the initial exposure was reported.
Eighteen of the 21 individuals (86%) reported hearing a novel, localized sound at the onset of symptoms in their homes and hotel rooms. Those that were affected described the sounds as directional, intensely loud, and with pure and sustained tonality. High-pitched sounds were reported by 16 (76%) of the individuals, while two (10%) described the stimulus as low-pitched. Words used to describe the sound included “buzzing,” “grinding metal,” “piercing squeals,” and “humming.” Further, the sounds were often associated with pressure-like or vibratory stimuli. The sensory stimuli were described as air baffling inside a moving car with the windows partially rolled down.
A common descriptor was that the sound was directional in nature and localized to a distinct area in the room. Several individuals noted that after changing locations within the room, the sensation disappeared and the associated symptoms reduced.
Three months following exposure persistent symptoms reported by the cohort, included cognitive (memory problems, feeling foggy or slowed and inability to concentrate) by 81%, balance (nausea, dizziness) by 71%, visual (light sensitivity and trouble reading) by 86%, auditory (ear pain, tinnitus, changes in hearing, sensitive to loud noise) by 68% of the individuals participating the retrospective evaluation. In addition, sleep impairments and headaches were reported by the majority of those exposed. Moderate to severe sensorineural hearing loss was identified in three of the 21 individuals evaluated at the University of Pennsylvania.
Cognitive symptoms, including memory difficulties and feeling cognitively slowed were determined to be the most problematic for individuals more than three months post-exposure. Compared to oculomotor and vestibular impairments, cognitive impairments also appeared to be the slowest to improve.
Among the maladies ruled out by the University of Pennsylvania team were collective delusional disorders and malingering. In addition, viral and chemical etiologies were excluded as likely causes of the symptoms. Although some of the symptoms were consistent with concussion or mild traumatic brain injury, these two conditions are unlikely to be the diagnosis of the individuals exposed to the mysterious auditory stimulus, according to the team of physicians completing the evaluations.
The determination of the team was the government personnel appeared to have sustained injury to widespread brain networks without an associated history of head trauma that resulted from exposure to what remains a mysterious auditory sensation.
Source: Swanson, R. et al. Neurologic manifestations among US government personnel reporting directional audible and sensory phenomena in Havana, Cuba. JAMA. Published online Feb 15, 2018.