Conor Finnegan, ABC News
Photo Credit: Andrew Caballero/AFP/Getty Images

U.S. personnel at the embassy in Havana who've experienced a rash of symptoms from mysterious "health attacks" appear to have suffered "widespread brain network dysfunction," but there's still no answer about the cause, according to a new peer-reviewed medical report.

The report, published Wednesday by the Journal of the American Medical Association, is the first of its kind on the question that has vexed U.S. officials for over a year now, with 24 Americans suffering from medically-confirmed symptoms, according to the State Department- or what the new report's authors call "neurotrauma from a nonnatural source."

Despite a lack of answers, the report provides some of the clearest details yet of what these Americans experienced in Havana - a buzzing or piercing noise, a pressure sensation, and an array of neurological symptoms that have lasted for months.