Made available in DSpace on 2015-04-14T13:22:13Z (GMT). No. of bitstreams: 1 448470.pdf: 202216 bytes, checksum: 7fc606e389537eec426fce6ebe25879e (MD5) Previous issue date: 2013-03-08 / 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. / No campo da neuropsicologia, as funcoes executivas (FE) vem recebendo um tratamento especial. Dentre os diversos componentes executivos investigados, destaca-se a tomada de decisao (TD). O Iowa Gambling Task (IGT), suporte empirico da Hipotese do Marcador Somatico, e o instrumento neuropsicologico mais utilizado internacionalmente para avaliar o processo de TD emocional. Estudos trazem evidencias de que o IGT e valido e sensivel tanto em pacientes neurol?gicos como psiquiatricos. Dentre os quadros neurologicos, o acidente vascular cerebral (AVC) pode desencadear diversos comprometimentos executivos; porem, pela escassez de investigacoes, ainda nao se sabe como se caracteriza o processo de TD nessa populacao e, mais especificamente, apos grupos de regioes lesadas. Assim, essa pesquisa pretendeu analisar as FE, mais especificamente a TD, em pacientes apos lesao cerebral vascular, buscando verificar duas relacoes neurofuncionais e uma relacao neuropsicologica cognitiva. No primeiro estudo visou-se a verificar o papel da lateralidade hemisferica no desempenho do IGT. Participaram 32 adultos com lesao de hemisferio direito (LHD), 31 participantes com lesao de hemisf?rio esquerdo (LHE), e 60 individuos controles. Como nao houve diferenca significativa entre os grupos clinicos, parece nao haver indicios de especializacoes hemisf?ricas na TD, sugerindo-se um efeito geral da lesao cerebral. No Estudo 2, objetivou-se comparar a performance de individuos que sofreram lesao cerebral frontal e participantes com lesao cerebelar no IGT. Participaram 9 pacientes em cada grupo clinico e 18 controles. O grupo controle diferenciou-se dos grupos clinicos e a diferenca entre os grupos clinicos foi limitrofe. De modo geral, o grupo de pacientes com lesao cerebelar apresentou um desempenho mais preservado do que os pacientes com lesao frontal, mas mais prejudicado do que os controles, demonstrando que o cerebelo tambem tem um papel importante na TD. No Estudo 3, correlacionou-se o desempenho de pacientes pos-AVC em testes de FE, procurando-se verificar se existe relacao entre componente quente das FE, como a TD, e outras habilidades executivas frias. Nao houve correlacoes significativas entre as principais vari?veis do IGT e dos outros instrumentos de FE, contribuindo para a discussao da multidimensionalidade das FE. Em conjunto, os estudos permitiram, pelas evidencias preliminares, caracterizar a contribuicao de diferentes regioes cerebrais para o processo de TD e, de forma geral, verificar o perfil decisional de alguns subgrupos clinicos pos-AVC, por meio de uma analise clinica comportamental.