CHICAGO (AP) New research found perplexing differences in the brains of U.S. diplomats who say they developed concussion-like symptoms after working in Cuba.
The findings published Tuesday only heighten the mystery of what may have happened to the workers.
The imaging tests showed the workers had less white matter than a comparison group of healthy people and other structural differences. But researchers say they can't explain the brain differences.
Between late 2016 and May 2018, several U.S. diplomats reported symptoms, some after hearing odd high-pitched sounds. Reported symptoms included balance problems, sleep and thinking difficulties, headaches and other complaints.
Cuba has denied any attack.
The study involved 40 people, including family members and others.
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