P1‐525: AMYLOID AGGREGATION IS ASSOCIATED WITH DECLINE ON DIGIT SPAN BACKWARD IN COGNITIVELY NORMAL ELDERLY MONOZYGOTIC TWINS. (1st July 2006) - Tomassen, Jori; den Braber, Anouk; Konijnenberg, Elles; ten Kate, Mara; Mulder, Sandra D.; Teunissen, Charlotte E.; Boomsma, Dorret I.; Scheltens, Philip; Visser, Pieter Jelle