P1‐132: DISRUPTION OF CHOLINERGIC NEUROTRANSMISSION, WITHIN A COGNITIVE CHALLENGE PARADIGM, PREDICTS Aβ‐RELATED COGNITIVE IMPAIRMENT IN PRECLINICAL ALZHEIMER'S DISEASE AFTER A 27‐MONTH DELAY INTERVAL. - Goldfarb, Danielle; Snyder, Peter J.; Maruff, Paul; Santos, Cláudia Y.; Ott, Brian R.; Salloway, Stephen; Yoo, Don C.; Noto, Richard B.; Alber, Jessica; Thompson, Louisa I.; Song, Alex (Alzheimer's & dementia: the journal of the Alzheimer's Association, 2018)