Decision-making of Prefrontal Patients with the Iowa Gambling Task: Unexpected Spared Performances and Preliminary Evidence for the Need of Alternative Measures
Résumé
Objective. Human decision-making is a growing area of research most commonly associated with the Iowa Gambling Task (IGT), which was first developed to assess patients with prefrontal cortex (PFC) damage. The IGT is now considered an appropriate task to predict behavioral disorders in various clinical populations. However, several studies have questioned the validity and reliability of the task, arguing that its particular payoff scheme may influence the decision-making process in terms of sensitivity to gain-loss frequency (GLF) rather than long-term outcome (the basic assumption of IGT). Despite the potential significance of this assertion for the diagnosis of decision-making deficits, few studies have addressed the influence of GLF on IGT performances in clinical populations, and there is no study to date that involves patients with prefrontal lobe damage. Method. We tested 17 patients with PFC damage and 17 matched healthy controls with the IGT to analyze influence in choice behavior of both long-term outcomes and GLF. Results. There was a difference between groups in the GLF score, but none between groups in the long-term outcome variable (the traditional measure). Our findings demonstrate that only control subjects seemed able to consider both long-term outcome and GLF. Conclusions. The discussion focuses on the contribution of empirical data, which may have implications for the clinical assessment of decision-making ability with the IGT.