Tomada de decisão no IGT : estudos neuropsicológicos pós-lesões cerebrais unilaterias, frontais ou cerebelares

Abstract

In the past few decades, executive functions (EF) have received special attention in neuropsychology. One of the most extensively researched executive components is decision making (DM). The Iowa Gambling Task (IGT), a major source of evidence toward the somatic marker hypothesis, is the most frequently used tool in the neuropsychological assessment of affective DM. Studies indicate that the IGT has adequate validity and sensitivity for the detection of DM impairment in patients with psychiatric and neurological issues. One of the most common sources of neurological lesions is cerebral stroke, which in some cases has been shown to cause executive impairment; however, due to a lack of studies in this particular population, not much is known about the DM process in these individuals or how this process is affected by strokes in different brain regions. Thus, the current study aimed to analyze EF, paying special attention to DM, in patients with ischemic strokes, so as to observe two distinct neurofunctional relationships and one cognitive neuropsychological one. In the first study, the role of hemispheric lateralization on the IGT was examined. A total of 32 adults with right hemisphere lesions, 31 with left hemisphere lesions and 60 control individuals took part in this study. As no significant differences between clinical groups were found, it appears that the impairment observed in IGT performance in connection with brain lesions has to do with the general presence of a lesion rather than its location. Study 2 allowed for a comparison of the IGT performance of individuals with frontal lobe versus cerebellar strokes. A total of 9 patients took part of each clinical group, while the control group was composed of 18 individuals. The DM performance observed in the control group was significantly different from that of the clinical groups, although only marginal differences were found between the clinical groups themselves. Overall, the IGT performance observed in patients with cerebellar damage appeared to be more preserved than that of individuals with frontal strokes, but less preserved than that of the control group, demonstrating that the cerebellum plays an important role in DM. Study 3 analyzed the correlations between the scores of stroke patients on various EF measures so as to investigate relationships between hot and cold executive functions. The fact that no significant correlations were found in this study supports the idea of multidimensionality in EF. Overall, the results of these studies offer preliminary evidence toward the characterization of the contribution of different brain regions to the DM process, as well as allowing for a description of DM profiles associated with certain clinical groups.