(CNN) Doctors remain baffled by concussion-like symptoms that manifested in US government personnel while they were on assignment in Havana, Cuba. These findings have left doctors wondering whether this pattern of symptoms can occur in a previously unseen way, without head trauma. A majority of the patients reported problems with memory, concentration, balance, eyesight, hearing, sleeping or headaches that lasted more than three months. The report also pointed out that while concussion patients often make a quick and full recovery, these patients experienced symptoms for months. In conclusion, the authors say their study raises "concern about a new mechanism for possible acquired brain injury from an exposure of unknown origin."

Source: CNN February 15, 2018 00:40 UTC