hypermnesia

Hypermnesia refers to an enhancement of memory function, sometimes observed under hypnosis or in certain pathological states. While 19th-century writers frequently described cases of hypermnesia, such as delirious individuals speaking forgotten languages, modern evidence suggests that memory recall under hypnosis isn't always superior to the waking state.1

The term "hypermnesia" was coined in the mid-19th century from Greek roots meaning "beyond" and "to remember". It can describe extraordinary memory abilities, like those of a Russian man known as "S" who possessed a detailed visual memory, or specific instances of heightened memory triggered by trauma or hypnosis in individuals with otherwise average recall. The exact anatomical or physiological basis for hypermnesia is still not fully understood.21