A new study reveals that the brains of diplomats who experienced mysterious neurological symptoms after working in Havana, Cuba, showed “significant differences” when compared to a control group. Researchers concluded that the diplomats have less white matter in their brains and less connectivity in the areas that control vision and hearing than healthy people, according to a study published in the Journal of the American Medical Association on Tuesday. The group of U.S. government workers reported strange sounds and sensations while serving in Havana between 2016 and 2018, and later experienced dizziness, hearing loss, and cognitive problems. Despite finding conclusive differences in their brains, the researchers were unable to say whether the changes were caused by the mysterious sounds and sensations reported in Cuba. The study states that: “The clinical importance of these differences is uncertain and may require further study.”