Between late 2016 and May 2018, more than 20 American staff members in the US Embassy in Cuba showed unusual symptoms that have been attributed to a mysterious “sonic attack” on the Embassy. 14 more Canadian diplomats also reported symptoms. The attack was unique and inexplicable. This week, the Journal of the American Medical Association published detailed findings that have stunned the medical community. The brains of those that were attacked have shrunk by as much as 15% – and may still be shrinking.

Scientists at the University of Pennsylvania examined brain scans of 40 individuals impacted by the “directional phenomena” attacks. They found that the area of the brain responsible for learning shrank by 5% or more. In addition, the areas of the brain responsible for auditory functions shrank approximately 15%. They likened the shrinkage to an “electricity brownout”.

Scientists are unable to explain the phenomena but fear a wartime attack on the general public could introduce longstanding, permanent disabilities. One scientist expressed his dismay:

“These types of changes in the brain are complexly unknown to us.”

The acoustic weapon theory gained further credence when an audio recording of a persistent, high-pitched drone sound was made by US personnel in Cuba in 2017. The Cuban government has consistently denied any involvement in the illnesses. Most officials believe Russia, who is allowed wide-ranging freedoms inside Cuba, was complicit if not directly responsible for the attacks.

Many of the patients are still struggling with symptoms more than a year after the attacks.