Cognitive Mechanisms Underlying Risky Decision-Making. A Study of Patients with Alzheimer’s Dementia

Patients with mild dementia of Alzheimer’s type (DAT) use to present problems in decision making. Several studies have analyzed the cognitive functions in the process of decision making, especially in situations under ambiguity. One approach is the somatic marker hypothesis from the Iowa Gambling Task (IGT) and the Gambling Index (IG). One problem is the lack of specificity from IGT indicators, for this reason some hypotheses have been proposed in order to solve these deficiencies, i.e. the Prospective Valence Learning (PVL). In this study, we apply the IGT to 10 patients and 10 control subjects. We analyze the PVL parameter: loss aversion parameter (λ), shape parameter (α), recency parameter (A), consistency (c) and task development in function of advantageous choices. Our results show that control subjects’ performance is better than DAT´, nevertheless, in the first stages there are not differences, these appear in the two last blocks. Whit the PVL parameters we obtain differences in α and c, and, to a lesser extent, in λ. According to PVL parameters, DAT patients can be described as sensible at loss subjects who are more influenced by immediate choice and a very low level of consistence, what implies the use of random choice strategies.