Medical Findings From U.S. Government Personnel in Cuba



Media advisory: To contact authors Randel L. Swanson, II, D.O., Ph.D. and Douglas H. Smith, M.D., email Holly Auer at

The full study is available on the JAMA website and the following link can be embedded in your story:


Bottom Line: Concussion-like symptoms were observed in U.S. government personnel in Cuba after they reported hearing intensely loud sounds in their homes and hotel rooms and feeling changes in air pressure caused by an unknown source. The symptoms were consistent with brain injury although there was no history of head trauma.

Why The Research Is Interesting: In late 2016, U.S. government personnel in Havana, Cuba, visited the embassy medical unit after experiencing unusual sound and sensory phenomena and the onset of neurological symptoms. The U.S. Department of State convened an expert panel in July 2017, which came to a consensus that the initial findings were most likely related to neurotrauma from a non-natural source and the department recommended further investigation of the symptoms. The University of Pennsylvania’s Center for Brain Injury and Repair was selected to coordinate the evaluation, treatment and rehabilitation of these patients. This article in JAMA reports the preliminary findings.

Who and When: 21 government personnel (11 women and 10 men) identified by the State Department and evaluated an average of 203 days following exposure to reported sound (described as “buzzing,” “grinding  metal,” “piercing squeals” or “humming”) and sensory phenomena (described as pressure-like or vibrating and likened to air “baffling” inside a moving car with the windows partially rolled down)

What (Study Measures): Audible and sensory phenomena coming from a distinct direction but from an unknown source (exposure); descriptions of symptoms and personnel experience with rehabilitation and return to work (outcomes)

How (Study Design): This was a case series, which describes the clinical course or outcomes of a group of patients. Researchers cannot control for exposures or differences that could explain patient outcomes and they cannot prove a causal relationship.

Authors: Randel L. Swanson, II, D.O., Ph.D., and Douglas H. Smith, M.D., of the University of Pennsylvania, Philadelphia, and coauthors


Study Limitations: To protect patient privacy, certain details typically reported in a case series were omitted, including specifics about geography, the relationship between individuals and individual demographics.

Study Conclusions: The unique circumstances of these patients and the clinical manifestations detailed in this report raise concern about a new mechanism for possible acquired brain injury from an exposure of unknown origin.

Related material:

  • Listen to an interview with authors from the University of Pennsylvania, Philadelphia, here. Download a transcript here.

For more details and to read the full study, please visit the JAMA website.


Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

#  #  #

For more information, contact JAMA Network Media Relations at 312-464-JAMA (5262) or email