Ecological relevance of the Iowa gambling task in patients with Alzheimer's disease and mild cognitive impairment

Background. - In spite of their extensive use, the ecological relevance of tasks dedicated to assessing real-world decision-making in a laboratory setting remains unclear. Objectives. - Our study aimed to evaluate the relationship between decision-making and behavioral competency and awareness of limitations. Methods. - A total of 20 patients with Alzheimer's disease (AD), 20 with amnestic mild cognitive impairment (aMCI) and 20 healthy controls (HC) were assessed for decision-making using the Iowa Gambling Task (IGT). Behavioral competency was evaluated by the Patient Competency Rating Scale (PCRS), which requires each participant and a relative to answer the same 30 questions on participant's competency and to rate each item, while awareness of limitations was evaluated by subtracting the self-rated score from the relative-rated score. Results. - Using the median-split approach, the proportion of disadvantageous decision-makers was higher in both the MCI and AD groups than in HC (P = 0.02 and P = 0.03, respectively), with no differences between clinical groups. The percentage of participants with poorer behavioral competency was also higher in the MCI and AD than in the HC (self-rated: P = 0.025 and P = 0.01, respectively; relative-rated: P = 0.008 and P = 0.008, respectively), again with no differences between MCI and AD. All groups were comparable in awareness. For all participants, disadvantageous decision-making was associated with both reduced behavioral competency and poor awareness of limitations (OR: 3.47, P = 0.03 and OR: 5.4, P = 0.004, respectively). Conclusion. - Our findings support the ecological relevance of the IGT. Behavioral competency integrity and awareness of limitations are both associated with advantageous decision-making profiles. (C) 2018 Elsevier Masson SAS. All rights reserved.