This atmospheric tale of terror, Francis Ford Coppola’s second venture, was considered so shocking that a test was devised to determine viewers’ fitness for watching it. The “D-13 Test” (screened before this feature) plumbs one’s predisposition for traumatic breakdown. “IF YOU FAIL THE TEST . . . you will be asked to leave the theatre!” Dementia 13 is no ordinary shockfest. The first stunning scene—with a body slowly sinking to a lake bottom, followed by a transistor radio still playing garbled music—propels you into the murky world of a family cursed by its own suffocating memories. Luana Anders plays the unwelcome visitor at the castle Halloran, a glum enclave of brooding siblings, their morbid mother, and a dark, dank secret. Lurking in the abundant shadows is an unnamed loony, wielding his woeful ax. Dementia 13 is a chopping spree in chiaroscuro.