mentia

The inverse of dementia. A state of mental incline rather than decline. Having not only all one's marbles but too many.

He could remember every almost word he had ever read, could recount conversations verbatim from several decades earlier, knew the names of minor characters, and the actors who had played them, in movies he had never seen. He could remember the name of a person he had met in passing many years ago, while some of his contemporaries searched for the names of their nearest and dearest. The diagnosis was direct: He was suffering from early onset mentia.