People with the syndrome have an unusual form of Eidetic memory to remember as well as recall any specific personal events or trivial details, including a date, the weather, what people wore on that day, from their past, almost in an organized manner.
Unlike other people with advanced memory abilities, such as savant syndrome (who tend to use calendrical calculation), individuals with hyperthymestic syndrome rely heavily on their personal "mental calendar",[REF] which is an automatic and obsessive process.