Nightmares affect the experience of sleep quality but not sleep .
Feb 13, 2015 . 0 = never, 1 = less than once a month, 2 = about once a month, 3 = twice .. Berry RB, Brooks R, Gamaldo CE, Harding SM, Lloyd RM, Marcus CL, Vaughn BV. . Darien, Illinois: American Academy of Sleep Medicine; 2013.