Memory of decisions: Relationship between decline of autobiographical memory and temporal discounting in Alzheimer's disease

Temporal discounting refers to the tendency to attribute higher value to a reward received early than to one received later. We evaluated this tendency in patients with Alzheimer's Disease. We also evaluated whether temporal discounting is associated with decline in autobiographical memory (i.e., the ability to remember past personal experiences), with executive dysfunction, and/or with general cognitive decline. We invited patients with AD and control participants to answer binary questions involving the choice between receiving a smaller amount of money earlier or a larger one later (e.g., "Which do you prefer, 10 euros in cash right now or 50 euros in a month?"). Results demonstrated higher temporal discounting in patients with AD than in control participants. Temporal discounting was significantly correlated with decline in AM and general cognitive decline but not with executive dysfunction in patients with AD. The tendency to decide based on immediate rewards (i.e., temporal discounting) in AD is related with difficulty in remembering information about experiences of previous decisions, and/or their consequences (i.e., decline in autobiographical memory).