The idiot savant: a review of the syndrome.

Since it was first described a century ago, the phenomenon of the idiot savant--the juxtaposition of severe mental handicap and prodigious mental ability--has remained unexplained. The author defines the condition, reviews and summarizes the world literature on this topic since the early reports, describes more recent cases, and catalogs and categorizes idiot savant abilities. Theories to explain the condition are reviewed, newer research findings are highlighted, and the far-reaching implications of the idiot savant syndrome for understanding normal brain function, particularly memory, are outlined.