The University of Miami is releasing its first report after examining American diplomats who suffered neurological damage while station in Havana.
Something happened to those diplomats who were serving in Cuba.
Lots of them reported cognitive issues, emotional changes, and a loss of balance.
Dr Michael Hoffer at the University of Miami says, "It's hard to imagine that this just arised by chance."
He can't conclude if they were victims of some kind of sonic attack: "We're not saying who caused it, or what caused it, or why, we're just saying a bunch of people came from the same place and had the same symptoms."
The U.S. continues to downsize its presence in Cuba, recently closing the immigration office in Havana.