Doctors say the victims of the attacks on U.S. diplomatic personnel in Cuba are showing unprecedented physical changes to their brains, the AP reported early Wednesday. The new findings cast further doubt on theories that whatever was used to harm the Americans was a sonic device. Medical tests reportedly indicate the Americans specifically had changes to the white-matter tracts that enable parts of the brain to communicate; acoustic waves have never before been shown to alter a brain’s white-matter tracts, said Columbia University biomedical engineer Elisa Konofagou, who is not involved in the investigation. The AP said doctors are treating the cases as never-before-seen abnormalities. The patients developed hearing, vision, balance, and memory damage while on assignment in Havana, after reporting hearing strange high-pitch sounds for months. It is still unclear how the white matter changes relate to the other neurological symptoms experienced by the diplomats. The Cuban government has denied any involvement in the attack.