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Advisor(s)
Abstract(s)
Enquadramento teórico: O lobo temporal, especialmente a sua região medial
(nomeadamente o hipocampo), é crucial para o funcionamento da memória. A teoria do
material-especifico pressupõe que lesões desta região providenciam a lateralização da
informação quanto ao seu material-específico (verbal vs não verbal). A literatura sugere
que o lobo temporal medial esquerdo é especifico para a memória verbal, enquanto que, o
lobo temporal medial direito é especifico para a memória não verbal. No entanto, é notada
uma inconsistência nos resultados, sendo que em alguns estudos a lateralização da
informação não é evidente. Uma das possíveis explicações para esta divergência, é o facto
de as tarefas de memória não verbal disponíveis não avaliarem corretamente devido à
componente verbal presente na memorização dos estímulos, criando assim uma dificuldade
em aceder ao funcionamento da região cerebral em questão. Esta avaliação assume um
papel especialmente importante na avaliação de pacientes com epilepsia do lobo temporal
(TLE).
Objetivo: Criar uma tarefa para avaliação da memória não verbal, de modo a que a
verbalização dos estímulos não interfira no processo de memorização.
Metodologia: Foi realizado um pré-teste de 23 desenhos aplicados a 30 sujeitos saudáveis.
Posteriormente foram selecionados 5 desenhos e foi-lhes atribuído um sistema de cotação
equivalente ao do subteste R.V da WMS-III. Foi aplicada a Tarefa Experimental e o
subteste R.V a 3 pacientes de epilepsia submetidos a uma hipocampectomia direita e 6
sujeitos de controlo. Foi comparado qualitativamente o desempenho de cada paciente com
dois controlos homogéneos. Foi feita uma análise estatística para comparar a amplitude da
diferença demonstrada no desempenho entre provas.
Resultados: Os resultados revelaram que todos os participantes apresentaram um
desempenho inferior na Tarefa Experimental do que na R.V. No entanto, a amplitude da
diferença entre provas foi estatisticamente significativa maior nos pacientes. Na Tarefa
Experimental todos os pacientes apresentaram um desempenho inferior ao dos respetivos
controlos.
Discussão: A presente investigação sugere que a verbalização dos estímulos parece mais
difícil na Tarefa Experimental do que na R.V, tendo os pacientes demonstrado uma maior
diferença entre as provas, nomeadamente com pior desempenho na Tarefa Experimental.
No entanto, este é um estudo que apenas nos orienta para esta possibilidade, devido ao
tamanho e características da amostra. A Tarefa Experimental deve, por isso, ser
investigada de uma forma mais profunda, deve ser testada a sua capacidade de
lateralização de lesão direita/esquerda, criados os dados padronizados e deve ainda ser
validada para esta população de forma a vir cobrir a lacuna existente na prática clinica.
Background: Temporal lobe, especially its mesial region, is crucial for processing of memory. Studies following lesions of this region have provided the material-specific theory, which suggests the lateralization of information: the dominant mesial temporal region is specific for verbal and non-dominant for visual memory. However, other investigators have failed to detect differential impairment in verbal and visuospatial tasks according to lesion laterality. One possible explanation is that the visual memory tasks used in such studies are not assessing the function because they are composed by stimuli that could be verbalized. This assessment of function is particularly important in the assessment of patients with temporal lobe epilepsy (TLE). Aim: Design a task to evaluate non-verbal memory, in a way that verbalization of the stimuli will not interfere with the memorization process. Methodology: A pretest with 23 designs was tested in 30 healthy subjects. We’ve selected 5 designs directly from pretest and created a scoring list equivalent to the subtest Visual Reproduction (V.R) of WMS-III. The Experimental Task and the V.R were administered in a sample of 3 epilepsy patients who were subject to a right hipocampectomy, and 6 controls. In a qualitative analysis we compared the performance of each patient with 2 matching controls. A statistics analysis was used to compare the amplitude of the difference present by patients and controls in the performance between tasks. Results: All participants had a poor performance in the Experimental Task than they had in V.R. However the amplitude of the difference between tasks was significantly higher in the patients group. In the Experimental task all the patients had a lower performance than matched controls. Discussion: The present investigation suggests that verbalizing stimuli seems harder in the Experimental Task than in the V.R, this could be why patients presented a higher difference between tasks than controls subjects, performing lower in Experimental task. However, because our sample size was small, this study could only guide us in that way. The Experimental Task should be profoundly investigated, lateralization capacity should be tested, standard data created and it must be validated in this kind of population, to help in clinical practice.
Background: Temporal lobe, especially its mesial region, is crucial for processing of memory. Studies following lesions of this region have provided the material-specific theory, which suggests the lateralization of information: the dominant mesial temporal region is specific for verbal and non-dominant for visual memory. However, other investigators have failed to detect differential impairment in verbal and visuospatial tasks according to lesion laterality. One possible explanation is that the visual memory tasks used in such studies are not assessing the function because they are composed by stimuli that could be verbalized. This assessment of function is particularly important in the assessment of patients with temporal lobe epilepsy (TLE). Aim: Design a task to evaluate non-verbal memory, in a way that verbalization of the stimuli will not interfere with the memorization process. Methodology: A pretest with 23 designs was tested in 30 healthy subjects. We’ve selected 5 designs directly from pretest and created a scoring list equivalent to the subtest Visual Reproduction (V.R) of WMS-III. The Experimental Task and the V.R were administered in a sample of 3 epilepsy patients who were subject to a right hipocampectomy, and 6 controls. In a qualitative analysis we compared the performance of each patient with 2 matching controls. A statistics analysis was used to compare the amplitude of the difference present by patients and controls in the performance between tasks. Results: All participants had a poor performance in the Experimental Task than they had in V.R. However the amplitude of the difference between tasks was significantly higher in the patients group. In the Experimental task all the patients had a lower performance than matched controls. Discussion: The present investigation suggests that verbalizing stimuli seems harder in the Experimental Task than in the V.R, this could be why patients presented a higher difference between tasks than controls subjects, performing lower in Experimental task. However, because our sample size was small, this study could only guide us in that way. The Experimental Task should be profoundly investigated, lateralization capacity should be tested, standard data created and it must be validated in this kind of population, to help in clinical practice.
Description
Keywords
Memória visual Hipocampo Epilepsia Visual memory Hippocampus Epilepsy