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Previous issue date: 2012-02-27 / Although Parkinson s Disease (PD) is predominantly a movement disorder, the presence of cognitive problems related to frontal function, even in the earliest stages has been observed. These problems include attentional, executive and memory deficits. A study using an experimental paradigm developed to investigate the effects of different encoding instructions on contextual memory showed that, unlike healthy controls, PD patients could not reverse their contextual memory deficits and take any advantage of encoding instructions. However, it is unclear whether they have a memory deficit or executive dysfunction would be accountable for results. Attentional and executive deficits observed in PD patients have important implications for daily activities, mainly when patient perform concomitant cognitive and motor activities that are attention demanding. Catechol- O-methyltransferase (COMT) is an enzyme that degrades cortical dopamine. Some studies have examined the relationship between the COMT val158met polymorphism and executive function in PD patients and have found low enzyme activity, associated to met/met polymorphism- implying higher prefrontal dopamine levels- is related to worse performance. However, a recent study did not demonstrate a direct effect of COMT genotype on the executive performance. The present study aimed to characterize different cognitive parameters of patients with PD and to assess their relationship with the COMT polymorphism. In this study participated 18 patients with early disease stage PD and 18 healthy adults matched for age, gender and education. Patients were selected from a data bank of patients genotyped for COMT polymorphism. All participants completed the Wisconsin Card Sorting Test (WCST), the Stroop Color and Word Test, and dual tasking paradigm. In addition, patients completed a contextual memory paradigm. No effect of COMT val158met genotype on frontal function in patients with PD (executive function and contextual memory) was observed. A decrease in cognitive task performance under dual-tasking was observed in PD patients, by contrast to healthy controls. Relative dual-task cognitive cost was significantly greater for PD patients compared to controls in the arithmetic-walking condition. In conclusion, difficulties in performing a cognitive task while walking can be influenced by the executive/attentional load of the task. / Embora a Doen?a de Parkinson (DP) seja predominantemente um dist?rbio do movimento, a presen?a de altera??es cognitivas relacionadas ? fun??o frontal tem sido observada mesmo nos est?gios iniciais da doen?a. Estas altera??es incluem d?ficits atencionais, executivos e de mem?ria. Um estudo usando um paradigma experimental desenvolvido para investigar os efeitos de diferentes instru??es codificadoras na mem?ria contextual mostrou que, ao contr?rio dos idosos, pacientes com DP n?o s?o capazes de reverter seus d?ficits de mem?ria e n?o tiram nenhuma vantagem das instru??es codificadoras. Entretanto, ainda n?o est? claro se estes pacientes t?m um d?ficit de mem?ria ou se as disfun??es executivas seriam as respons?veis pelos resultados observados. D?ficits atencionais e executivos observados em pacientes com DP t?m implica??es importantes nas atividades di?rias, principalmente quando o paciente desempenha atividades concomitantes cognitivas e motoras que requerem aten??o. A catecol- O-metiltransferase (COMT) ? uma enzima que degrada a dopamina cortical. Alguns estudos t?m examinado a rela??o entre o polimorfismo val158met da COMT e fun??o executiva em pacientes com DP e t?m observado que a atividade reduzida da enzima, relacionada ao polimorfismo, que implica em maiores n?veis de dopamina no c?rtex pr?-frontal, est? associada a uma pior performance. Entretanto, um estudo recente n?o demonstrou um efeito direto do gen?tipo da COMT no desempenho executivo. O presente estudo teve por objetivo caracterizar diferentes par?metros cognitivos de pacientes com DP e verificar sua rela??o com o polimorfismo da COMT. Neste estudo participaram 18 pacientes em est?gios iniciais da DP e 18 adultos saud?veis, pareados por idade, g?nero e n?vel educacional. Os pacientes foram selecionados de um banco de pacientes genotipados para o polimorfismo da COMT. Todos os participantes completaram o Teste de Classifica??o de Cartas de Wisconsin, o Teste de Stroop e o paradigma para avalia??o da realiza??o de tarefas simult?neas. Adicionalmente, os pacientes com DP completaram o paradigma de mem?ria contextual. N?o foi observado efeito do polimorfismo val158met da COMT sobre a fun??o frontal (fun??o executiva e mem?ria contextual) dos pacientes com DP. Os pacientes apresentaram um decl?nio cognitivo na realiza??o das atividades simult?neas, ao contr?rio dos controles. O custo cognitivo associado ? realiza??o da tarefa aritm?tica juntamente ? caminhada foi significativamente maior para os pacientes com DP, em rela??o aos controles. Em conclus?o, as dificuldades em realizar uma atividade cognitiva e motora simultaneamente podem ser influenciadas pela carga executiva/atencional da atividade.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5442 |
| Date | 27 February 2012 |
| Creators | Lima, Daiane Borba de |
| Contributors | Bromberg, Elke |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
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