Now, the lead author of the US government's report on the incident has said that the attacks may have been caused by microwave weapons.
In an interview with the New York Times, Douglas Smith, director of the University of Pennsylvania's Center for Brain Injury and Repair said that the main suspect of the cause of the victims' injuries are microwaves.
"It's almost like a concussion, but without a concussion -- meaning that they look like individuals who have persistent concussion symptoms but have no history of head impact," Smith told CNN. "Just like we have ways to prevent people from having a concussion, you could think of maybe protecting your brain from these energy sources."
Symptoms of the attacks include “sharp ear pain, headaches, ringing in one ear, vertigo, disorientation, attention issues and signs consistent with mild traumatic brain injury or concussion,” US officials told Congress in a January hearing.
In March, the US government medical team lead by Smith released a report detailing the potential causes of the attacks but did not mention any use of microwaves.
There have been no reports of tourists experiencing a sonic attack, but that hasn't stopped the US from withdrawing a majority of its embassy staff in Cuba and issuing a health alert for US citizens traveling to China. The US has not directly accused the Cuban government of carrying out the attacks but says the country is responsible for safeguarding the diplomats' welfare.
Dr. Mitchell Valdes-Sosa, a well known Cuban scientist who is studying the issue on behalf of the Cuban government called the findings "science fiction."
