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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Aplicação de redes neurais artificiais paraconsistentes como método de auxílio no diagnóstico da doença de Alzheimer / Application of artificial neural networks paraconsistents as a method of aid in the diagnosis of Alzheimer disease

Lopes, Helder Frederico da Silva 02 July 2009 (has links)
A análise visual do eletroencefalograma (EEG) tem se mostrado útil na ajuda diagnóstica da doença de Alzheimer (DA), sendo indicado em alguns protocolos clínicos quando o diagnóstico permanece em aberto após a avaliação inicial. Porém, tal análise está sujeita naturalmente à imprecisão inerente de equipamentos, movimentos do paciente, registros elétricos e variação da interpretação da análise visual do médico. A teoria das Redes Neurais Artificiais (RNA) tem-se mostrado muito apropriado para tratar problemas como predição e reconhecimento de padrões de sinais em outras áreas do conhecimento. Neste trabalho utilizou-se uma nova classe de RNA, a Rede Neural Artificial Paraconsistente (RNAP), caracterizada pela manipulação de informações incertas, inconsistentes e paracompletas, destinada a reconhecer padrões predeterminados de EEG e de avaliar sua aplicabilidade como método auxiliar para o diagnóstico da DA. Trinta e três pacientes com DA provável e trinta e quatro pacientes controles foram submetidos ao registro de exames de EEG durante a vigília em repouso. Considerou-se como padrão normal de um paciente, a atividade de base entre 8,0 Hz e 12,0 Hz (com uma frequência média de 10 Hz), permitindo uma variação de 0.5 Hz. A RNAP foi capaz de reconhecer ondas de diferentes bandas de frequência (teta, delta, alfa e beta) aplicadas ao uso clínico do EEG, levando a uma concordância com o diagnóstico clínico de 82% de sensibilidade e 61% de especificidade. Com estes resultados, acredita-se que a RNAP possa vir a ser uma ferramenta promissora para manipular análise de EEG, tendo em mente as seguintes considerações: o interesse crescente de especialistas em análise visual de EEG e a capacidade da RNAP tratar diretamente dados imprecisos, inconsistentes e paracompletos, fornecendo uma interessante análise quantitativa e qualitativa / The visual analysis of EEG has shown useful in helping the diagnosis of Alzheimer disease (AD) when the diagnosis remains uncertain, being used in some clinical protocols. However, such analysis is subject to the inherent equipment imprecision, patient movement, electrical records, and physician interpretation of the visual analysis variation. The Artificial Neural Network (ANN) could be a helpful tool, appropriate to address problems such as prediction and pattern recognition. In this work, it has use a new class of ANN, the Paraconsistent Artificial Neural Network (PANN), which is capable of handling uncertain, inconsistent, and paracomplet information, for recognizing predetermined patterns of EEG and to assess its value as a possible auxiliary method for AD diagnosis. Thirty three patients with Alzheimer\'s disease and thirty four controls patients of EEG records were obtained during relaxed wakefulness. It was considered as normal patient pattern, the background EEG activity between 8.0 Hz and 12.0 Hz (with an average frequency of 10 Hz), allowing a range of 0.5 Hz. The PANN was able to recognize waves that belonging to their respective bands of clinical use (theta, delta, alpha, and beta), leading to an agreement with the clinical diagnosis at 82% of sensitivity and at 61% of specificity. Supported with these results, the PANN could be a promising tool to manipulate EEG analysis, bearing in mind the following considerations: the growing interest of specialists in EEG analysis visual and the ability of the PANN to deal directly imprecise, inconsistent and paracomplet data, providing an interesting quantitative and qualitative analysis
372

Impacto da cirurgia de epilepsia no desempenho cognitivo de pacientes com esclerose mesial temporal unilateral / Impact of epilepsy surgery on cognitive performance of patients with unilateral mesial temporal sclerosis

Lima Filho, Humberto de Castro 21 November 2017 (has links)
INTRODUÇÃO: A esclerose mesial temporal (EMT) é uma das principais causas de epilepsia focal farmacorresistente. O prognóstico cirúrgico é excelente, porém pode ocorrer declínio cognitivo pós-operatório. Este estudo teve como objetivo verificar o impacto cognitivo da lobectomia temporal anterior em pacientes com EMT, levando em consideração o padrão de envolvimento eletrográfico ictal. MÉTODOS: Foram selecionados pacientes com epilepsia farmacorresistente secundária à EMT unilateral e sujeitos sem epilepsia, com idade entre 18 e 55 anos e oito ou mais anos de escolaridade. Os pacientes foram agrupados de acordo com o lado da EMT em esquerda (EMTE) e direita (EMTD). Aqueles que recusaram cirurgia foram incluídos no grupo-controle clínico e os que optaram por cirurgia foram incluídos no grupo cirúrgico. Pacientes do grupo cirúrgico foram submetidos a vídeo-EEG e teste de Wada. Pacientes com representação de linguagem atípica foram excluídos. O grupo cirúrgico foi subdividido de acordo com o padrão eletrográfico ictal determinado pelo vídeo-EEG em: envolvimento eletrográfico ictal exclusivamente ipsilateral e envolvimento eletrográfico ictal bilateral. A avaliação neuropsicológica dos pacientes foi realizada em dois momentos. Os sujeitos sem epilepsia foram avaliados apenas uma vez. Para análise estatística, foram utilizados testes paramétricos ou não paramétricos a depender da normalidade da distribuição dos dados. Os grupos foram comparados em relação a variáveis clínicas, pontuações basais nos testes neuropsicológicos e diferenças médias das pontuações entre a segunda e primeira avaliações. Também foram comparadas as pontuações médias da primeira e segunda avaliações dentro de um mesmo grupo. O grupo clínico foi utilizado para o cálculo do índice de mudança confiável (RCI). Considerou-se melhora no desempenho cognitivo escore Z > 1,645 e piora escore Z < -1,645. RESULTADOS: A análise final incluiu 65 pacientes com epilepsia e 40 sujeitos sem epilepsia. Vinte e um pacientes (nove EMTE, doze EMTD) recusaram cirurgia e foram incluídos no grupo clínico. O grupo cirúrgico foi composto por 25 pacientes com EMTE e 19 com EMTD. Dez pacientes do grupo cirúrgico com EMTE apresentaram envolvimento ictal exclusivamente ipsilateral e 15 bilateral. No grupo cirúrgico com EMTD, dez apresentaram envolvimento ictal exclusivamente ipsilateral e nove bilateral. Os pacientes com EMT apresentaram desempenho cognitivo inferior aos sujeitos sem epilepsia, sendo mais evidente comprometimento de memória nos pacientes com EMTE. A cirurgia provocou declínio de memória no grupo com EMTE e tendência de melhora em funções executivas em ambos os grupos. O envolvimento eletrográfico bilateral associou-se a menor declínio pós-operatório de memória verbal no grupo com EMTE. O envolvimento eletrográfico bilateral associou-se à piora no desempenho pós-operatório no teste de repetição de dígitos na ordem inversa no grupo com EMTD. Foi observada redução na pontuação da escala de depressão, após a cirurgia, em pacientes com EMTE e envolvimento eletrográfico ictal bilateral. CONCLUSÃO: O envolvimento eletrográfico bilateral não se associou a maior risco de declínio de memória pós-operatório, portanto, o tratamento cirúrgico não deve ser contraindicado nestes pacientes / INTRODUCTION: Mesial temporal sclerosis (MTS) is a major cause of drug-resistant focal epilepsy. Surgical prognosis is excellent, but surgery can lead to cognitive decline. The present study aimed to evaluate the impact of anterior temporal lobectomy in MTS patients, taking into account the ictal electrographic pattern. METHODS: Patients with drug-resistant epilepsy secondary to unilateral MTS and subjects without epilepsy, aged between 18 and 55 years, with eight or more education years were selected. Patients were grouped according to MTS side as left (L-MTS) or right (R-MTS). Patients who declined surgery were included as clinical controls, and those who opted for surgery were included in the surgical group. The surgical group underwent video-EEG monitoring and Wada testing. Patients with atypical language representation were excluded. According to the ictal electrographic pattern determined by video-EEG, the surgical group was subdivided as: exclusive ipsilateral electrographic ictal involvement or bilateral electrographic ictal involvement. Patients underwent neuropsychological evaluation on two occasions. Subjects without epilepsy were evaluated once. Parametric or non-parametric tests were used according to normality of data distribution. Groups were compared in relation to clinical variables, baseline neuropsychological test scores, and mean scores differences between second and first evaluations. Mean first and second evaluation scores were also compared within the same group. The clinical group data was used to calculate the reliable change index (RCI). Z-scores > 1.645 were considered improvement, and Z-scores <-1,645 as decline. RESULTS: Analysis included 65 patients with epilepsy and 40 subjects without epilepsy. Twenty-one patients (nine L-MTS, twelve R-MTS) declined surgery and were included as clinical controls. The surgical group consisted of 25 patients with L-MTS and 19 with R-MTS. Ten patients in the L-MTS surgical group presented exclusive ipsilateral ictal involvement and 15 presented bilateral involvement. In the R-MTS surgical group, ten presented exclusive ipsilateral ictal involvement and nine presented bilateral involvement. Patients with MTS had worse cognitive performance than subjects without epilepsy. L-MTS group presented more impairment in memory. Surgery lead to memory decline in the L-MTS group and to a tendency towards improvement on executive functioning in both groups. Bilateral electrographic involvement was associated with less verbal memory decline in the L-MTS group. Bilateral electrographic involvement was associated with worsening in digit span in R-MTS group and improved scores in the depression scale in L-MTS group. CONCLUSION: Bilateral electrographic involvement was not associated with a higher risk of postoperative memory decline. Epilepsy surgery should therefore not be denied to these patients
373

Avaliação de métodos de análises não lineares em sinais eletroencefalográficos na presença de oscilações de alta frequência em pacientes portadores de epilepsia refratária / Evaluation of nonlinear analysis methods in electroencephalographic signals in the presence of high frequency oscillations in patients with refractory epilepsy

Duque, Juliano Jinzenji 09 August 2017 (has links)
A eletroencefalografia (EEG) é uma das evidências tomadas na avaliação de indicação cirúrgica, em casos de pacientes portadores de epilepsia refratária a medicamentos, que pode auxiliar na localização da área responsável pela origem das crises epilépticas. Ao longo das últimas décadas, além das bandas de frequências já tradicionalmente avaliadas (até cerca de 40Hz), a EEG tem despertado o interesse de pesquisadores também para bandas de frequências mais altas. Passaram a ser encontradas evidências de que oscilações de alta frequência, conhecidas por HFO (High Frequency Oscillations), podem ser usadas como biomarcadores de epilepsia. Diversos estudos têm sido realizados em busca de uma melhor compreensão sobre HFO, a fim de viabilizar sua utilização em aplicações clínicas. Entretanto, características não lineares e de complexidade, que podem contribuir na análise de sinais com origem em sistemas biológicos, não têm sido investigadas neste tipo de sinais. Este estudo propôs a investigação de características extraídas de sinais de EEG com presença de HFO, de pacientes portadores de epilepsia refratária, através de métodos considerados como de análise não linear. Análise de Dinâmica Simbólica, Análise de Flutuações Destendenciadas (DFA), Entropia Multiescala (MSE) e Análise qSDiff foram aplicadas em segmentos de sinais de EEG intracraniano, amostrados a 5kHz, de pacientes portadores de epilepsia refratária, e também em alguns sinais simulados de características conhecidas para fins de comparação. Os resultados dos diferentes métodos investigados apontaram características semelhantes entre os segmentos de EEG analisados e séries simuladas de ruído browniano, sugerindo que os sinais de EEG em geral têm perfil bastante suavizado, são não estacionários e exibem correlações de longo alcance. Foram também levantadas evidências de que tanto HFO quanto os segmentos de EEG onde estão inseridas têm padrões mais regulares de variação e são menos complexas que segmentos de EEG sem HFO, sugerindo a degradação da complexidade fisiológica desta região cerebral, que poderia estar relacionada com mecanismos fisiopatológicos da epilepsia. Todos os métodos investigados sugeriram que as características e propriedades não lineares, relacionadas a complexidade inerente dos sinais de EEG, podem ser úteis na análise de HFO, principalmente pelas evidências de que estas características se alteram nas HFO, quando comparadas ao restante do sinal onde elas se encontram e também a outros sinais sem sua presença. / Electroencephalography (EEG) is one of the evidences taken in the evaluation of surgical indication, in cases of patients with drug refractory epilepsy, which may help in locating the area responsible for the origin of epileptic seizures. Over the last few decades, in addition to the frequency bands that have traditionally been evaluated (up to about 40Hz), the EEG has attracted researchers also to higher frequency bands. Evidence has been found that high frequency oscillations (HFO), can be used as biomarkers of epilepsy. Many studies have been carried out in search of a better understanding about HFO, in order to make it feasible to use in clinical applications. However, nonlinear and complex features, which may contribute to the analysis of signals originating from biological systems, have not been investigated in this type of signals. This study proposed the investigation of features extracted from EEG signals with HFO of patients with refractory epilepsy, using nonlinear analysis methods. Symbolic Dynamics Analysis, Detrended Fluctuation Analysis (DFA), Multiscale Entropy (MSE) and qSDiff Analysis were applied to segments of intracranial EEG signals, sampled at 5kHz, from patients with refractory epilepsy, as well as some features-known simulated signals for comparison purposes. Results of the different investigated methods pointed out similar features between the analyzed EEG segments and the simulated series of Brownian noise, suggesting that EEG signals, in general, have a very smoothed profile, are nonstationary and exhibit long- range correlations. Evidence has also been raised that both HFO and the EEG segments where they are inserted have more regular patterns of variation and are less complex than EEG segments without HFO, suggesting the degradation of the physiological complexity of this brain region, which could be related to pathophysiological mechanisms of epilepsy. All the investigated methods suggested that nonlinear features and properties, related to the inherent complexity of EEG signals, may be useful in HFO analysis, mainly because of the evidence that these features change in HFOs when compared to the rest of the signal where they are and other signals without their presence.
374

Atypical electrical brain activity related to attention and inhibitory control in children who stutter

Piispala, J. (Johanna) 22 January 2019 (has links)
Abstract The aim of this study was to discover attention- and inhibitory control-related differences in the electrical activity of the brain in 6- to 9-year-old children who stutter (CWS) compared to typically developed children (TDC). For studies I and II, the study group consisted of 11 CWS (mean age 8.1 years, age range 6.3–9.5 years; all boys) and 19 fluently speaking children (mean age 8.1 years, age range 5.8–9.6 years; 7 girls). In study III, the participants were twelve boys who stutter (mean age 7.97 years, range 6.3–9.5 years) and 12 typically developed, fluently speaking boys (mean age 8.01 years, range 5.8–9.6 years). The CWS were recruited through local speech therapists and special teachers and newspaper advertisements, while controls were recruited from schools and preschools and among families of department staff and friends. Electroencephalography (EEG) was recorded during a visual Go/Nogo task, which forms a conflict between the pre-potent Go-response and inhibition of response in the Nogo condition, demanding inhibitory control. This EEG data was investigated with conventional event-related potentials (ERP) analysis, potential map and global field power (GFP) analysis and a time-frequency analysis including the periods between tasks. In the ERP analysis, the CWS had a delayed N2 component in the Go condition and a poorly defined P3 component. The potential maps and GFP waveforms confirmed the findings in the Go condition, but also revealed differences in the Nogo condition, described as a prolonged and excessive N2component and an absent P3 component in the CWS. These results indicate problems in the evaluation and classification of the stimulus and the response preparation and inhibition of the response. In the time-frequency analysis, the CWS showed reduced occipital alpha power in the “resting” or preparatory period between visual stimuli, particularly in the Nogo condition. Therefore, the CWS demonstrate reduced inhibition of the visual cortex in the absence of visual stimuli, which is likely related to problems in attentional gating. This newly discovered lack of occipital alpha modulation indicates elementary differences in the regulation of visual information processing in CWS. These findings support the view of stuttering as part of an extensive brain dysfunction involving also attentional and inhibitory networks. / Tiivistelmä Tutkimuksen tavoitteena oli tunnistaa tarkkaavuuteen ja inhibitiokontrolliin liittyviä eroja aivojen sähköisessä toiminnassa 6–9-vuotiailla lapsilla, jotka änkyttävät verrattuna tavanomaisesti kehittyviin lapsiin. Osatöissä I ja II koeryhmässä oli 11 änkyttävää lasta (iän keskiarvo 8.1 vuotta, ikäjakauma 6.3–9.5 vuotta) ja verrokkiryhmässä 19 sujuvasti puhuvaa lasta (keskiarvo 8.1 vuotta, jakauma 5.8–9.6 vuotta; 7 tyttöä). Osatyössä III koeryhmässä oli 12 änkyttävää poikaa (keskiarvo 7.97, jakauma 6.3–9.5 vuotta) ja verrokkiryhmässä 12 sujuvasti puhuvaa poikaa (keskiarvo 8.01 vuotta, jakauma 5.8–9.6 vuotta). Koehenkilöitä haettiin puheterapeuttien ja erityisopettajien välityksellä sekä lehti-ilmoituksilla. Verrokkiryhmän osallistujat rekrytoitiin kouluista, esikouluista sekä henkilökunnan ja ystävien perheiden joukosta. Elektroenkefalografia (EEG) rekisteröitiin visuaalisen Go/Nogo-tehtävän aikana. Tehtävässä ennakoidun Go-vasteen ja Nogo-tilanteessa vaadittavan reaktiosta pidättäytymisen välille syntyvä ristiriita kuormittaa inhibitiokontrollia. EEG-dataa arvioitiin herätevasteiden avulla, tutkimalla jännitekarttojen ja koko pään jännitevaihteluiden eroja sekä käyttämällä aika-taajuusanalyysia, mihin sisältyi myös tehtävien välinen aika. Herätevasteanalyysissä änkyttävillä lapsilla oli viivästynyt N2-vaste Go-tilanteessa ja huonosti erottuva P3-vaste. Jännitekarttojen ja koko pään jännitevaihteluiden perusteella tämä löydös vahvistui, mutta ryhmät erosivat toisistaan myös Nogo-tilanteessa. Änkyttävillä lapsilla N2-vaste oli pidentynyt ja voimakkaampi ja P3-vaste puuttui. Löydökset viittaavat ongelmiin ärsykkeen arvioinnissa ja luokittelussa sekä reaktion valmistelussa ja inhibitiossa. Aika-taajuusanalyysissa änkyttävillä lapsilla oli okkipitaalialueilla merkittävästi vähemmän alfataajuista toimintaa tehtävien välisen ”lepotilan” tai valmistautumisvaiheen aikana erityisesti Nogo-tilanteessa. Änkyttävillä lapsilla näköaivokuoren inhibitio ärsykkeen puuttuessa on näin ollen heikentynyt, mikä viittaa häiriöön tarkkaavuuden suuntaamisessa. Tämä todettu alfatoiminnan säätelyn puuttuminen ilmentää perustavanlaatuisia eroja näköärsykkeen käsittelyssä änkyttävillä lapsilla. Löydökset tukevat näkemystä änkytyksestä osana laaja-alaista aivojen toiminnan häiriötä, joka käsittää todennäköisesti myös tarkkaavuuteen ja inhibitiokontrolliin liittyviä verkostoja.
375

A comunicação do paciente em coma: estudo das manifestações fisiológicas dos pacientes em coma na unidade de terapia intensiva e suas possíveis respostas comunicativas / The communication of patients in coma: a study of the physiological manifestations of patients in coma in intensive care unit and their possible communicative responses

Mimura, Verusk Arruda 15 June 2018 (has links)
Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2018-08-01T11:34:26Z No. of bitstreams: 1 Verusk Arruda Mimura.pdf: 4908287 bytes, checksum: 6e6d3694f80bb455a6f750aaea622f91 (MD5) / Made available in DSpace on 2018-08-01T11:34:26Z (GMT). No. of bitstreams: 1 Verusk Arruda Mimura.pdf: 4908287 bytes, checksum: 6e6d3694f80bb455a6f750aaea622f91 (MD5) Previous issue date: 2018-06-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This present thesis is an analysis on communication of the body in coma in intensive care units. The communication process between those patients and the health staff demands constant evaluation on their perception. Recent studies have indicated possibilities of flaws in classifying patients in coma and they have questioned the excessive faith that has been placed on technological devices. Therefore, we propose here the investigation of the primary communication of patients in coma through olfaction, making use of an interdisciplinary study involving communication and health sciences. This study is in accordance with the studies of Semiotics of Culture as well as with the advances in the field of medical research which suggest changes of the established paradigm for the diagnose of those patients. The objective of this study is identifying from olfaction stimulation any probable evidence of communication of patients in coma, by reading and interpreting any possible physiological alterations such as electroencephalographic recording, blood pressure, heart rate and oxygen blood saturation, associated to the observation of subjective signs emitted by the body, from face and body expressions, searching for a possible triggering of the olfactory memory. The physiological responses of patients in coma were compared to those of outpatients. As to face the lack of meaningful statistic alterations on patients in coma, the outpatients were called to take a central role on this present study. Yet, the qualitative analysis makes it possible to imply that the primary responses delivered by the body of the patients in coma might be considered as communication when submitted to olfactory stimulation carried by the combination of other stimuli sensitive to the senses. This interdisciplinary study points to the need of creating between the fields of communication and health an essential link toward the studies of the human body. The theoretical framework was built around the following authors: A. R. Luria (1966, 1979, 1982, 1991), Oliver Sacks (1988, 2013), Edgar Morin (1973, 1996), Gerald M. Edelman (1992), Norval Baitello Jr. (1997, 2005, 2012), F. S. Machado (2006), Hawkes and Doty (2009), Jox et al. (2012), E. Delamonica (1984) among others / A presente tese é uma reflexão sobre a comunicação do corpo em coma em uma unidade de terapia intensiva. O processo de comunicação dessespacientes com a equipe de saúde requer avaliações constantes de sua percepção. Estudos recentes apontam possibilidades de falhas na classificação dos pacientes em coma e questionam a confiança demasiada que se deposita em aparelhos tecnológicos. Dessa forma, propõe-se a investigação da comunicação primária desses pacientes, através do sentido do olfato, por meio de um estudo de caráter interdisciplinar, envolvendo comunicação e as ciências da saúde. Este trabalho está em consonância com os estudos da Semiótica da Cultura e com os avanços na área da pesquisa médica, que sugerem mudanças no paradigma estabelecido para o diagnóstico desses pacientes.O objetivo deste estudo foi identificar, a partir do estímulo olfativo, indícios do processo de comunicação do paciente em coma, através da leitura e da interpretação de possíveis alterações fisiológicas, como registro eletroencefalográfico, pressão arterial, frequência cardíaca e percentual de saturação de oxigênio no sangue, associados à observação de sinais subjetivos emitidos pelo corpo, por meio de expressões faciais e corporais, buscando-se uma possível ativação da memória olfativa. As respostas fisiológicas dos pacientes em coma foram comparadas com as repostas fisiológicas dos pacientes ambulatoriais. A ausência de alterações estatísticas significativas nos pacientes em coma fez com que os pacientes do grupo ambulatorial assumissem um papel central no desenrolar deste estudo. Já a análise qualitativa permite inferir que as respostas primárias apresentadas pelo corpo do paciente em coma, submetido ao estímulo olfativo, podem ser interpretadas como comunicação quando carregadas pela combinação de outros estímulos sensíveis aos órgãos do sentido. Este estudo interdisciplinar aponta para a necessidade de se estabelecer, entre as áreas de comunicação e de saúde, um elo essencial para os estudos sobre o corpo. O quadro teórico assenta-se nos autores: A. R. Luria (1966, 1979, 1982, 1991), Oliver Sacks (1988, 2013), Edgar Morin (1973, 1996), Gerald M. Edelman (1992), Norval Baitello Jr. (1997, 2005, 2012), F. S. Machado (2006), Hawkes e Doty (2009), Jox et al. (2012), E. Delamonica (1984) entre outros
376

Análise de wavelets com máquina de vetor de suporte no eletrencefalograma da doença de Alzheimer / Wavelets analysis with support vector machine in Alzheimer\'s disease EEG

Kanda, Paulo Afonso Medeiros 07 March 2013 (has links)
INTRODUÇÃO. O objetivo deste estudo foi responder se a transformada wavelet Morlet e as técnicas de aprendizagem de Máquina (ML), chamada Máquinas de Vetores de Suporte (SVM) são adequadas para procurar padrões no EEG que diferenciem controles normais de pacientes com DA. Não há um teste de diagnóstico específico para a doença de Alzheimer (DA). O diagnóstico da DA baseia-se na história clínica, neuropsicológica, exames laboratoriais, neuroimagem e eletroencefalografia. Portanto, novas abordagens são necessárias para permitir um diagnóstico mais precoce e preciso e para medir a resposta ao tratamento. EEG quantitativo (EEGq) pode ser utilizado como uma ferramenta de diagnóstico em casos selecionados. MÉTODOS: Os pacientes eram provenientes do Ambulatório do Grupo de Neurologia Cognitiva e do Comportamento (GNCC) da Divisão de Clínica Neurológica do HCFMUSP ou foram avaliados pelo grupo do Laboratório de Eletrencefalografia Cognitiva do CEREDIC HC-FMUSP. Estudamos EEGs de 74 indivíduos normais (33 mulheres/41 homens, com idade média de 67 anos) e 84 pacientes com provável DA leve a moderada (52 mulheres/32 homens, idade média de 74,7 anos. A transformada wavelet e a seleção de atributos foram processadas pelo software Letswave. A análise SVM dos atributos (bandas delta, teta, alfa e beta) foi calculada usando-se a ferramenta WEKA (Waikato Ambiente para Análise do Conhecimento). RESULTADOS: Na classificação dos grupos controles e DA obteve-se Acurácia de 90,74% e área ROC de 0,90. Na identificação de um único probando dentre todos os demais se conseguiu acurácia de 81,01% e área ROC de 0,80. Desenvolveu-se um método de processamento de EEG quantitativo (EEGq) para uso na diferenciação automática de pacientes com DA versus indivíduos normais. O processo destina-se a contribuir como complemento ao diagnóstico de demência provável principalmente em serviços de saúde onde os recursos sejam limitados / INTRODUCTION. The aim of this study was to answer if Morlet wavelet transform and machine learning techniques (ML), called Support Vector Machines (SVM) are suitable to look for patterns in EEG to differentiate normal controls from patients with AD. There is not a specific diagnostic test for Alzheimer\'s disease (AD). The diagnosis of AD is based on clinical history, neuropsychological testing, laboratory, neuroimaging and electroencephalography. Therefore, new approaches are needed to allow an early diagnosis and accurate to measure response to treatment. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. METHODS: The patients came from the Clinic Group Cognitive Neurology and Behavior (GNCC), Division of Clinical Neurology HCFMUSP or evaluated by the group of the Laboratory of Cognitive electroencephalography CEREDIC HCFMUSP. We studied EEGs of 74 normal subjects (33 females/41 men, mean age 67 years) and 84 patients with mild to moderate probable AD (52 females/32 men, mean age 74.7 years. Wavelet transform and the selection of attributes were processed by software Letswave. SVM analysis of attributes (bands delta, theta, alpha and beta) was calculated using the tool WEKA (Waikato Environment for Knowledge analysis). RESULTS: The group classification of controls and DA obtained an accuracy of 90.74% and ROC area 0.90. The identification of a unique proband among all others was achieved with accuracy of 81.01% and ROC area 0.80. It was developed a method of processing EEG quantitative (qEEG) for use in automatic differentiation of AD patients versus normal subjects. This process is intended to complement the diagnosis of probable dementia primarily in health services where resources are limited
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Mécanismes de prise de décision dans des environnements conflictuels : approches comportementales, computationnelles et électrophysiologiques / Decision-making mechanisms in conflicting environments : behavior, computations and electrophysiology

Servant, Mathieu 30 November 2015 (has links)
Une décision perceptive est un processus délibératif consistant à choisir une proposition catégorielle ou un plan d'action parmi plusieurs alternatives sur la base d'information sensorielle. Les modèles de prise décision font l'hypothèse que l'information sensorielle est accumulée au cours du temps jusqu'à un seuil décisionnel. Ces modèles ont récemment reçu un support empirique important grâce à la découverte de neurones accumulateurs dans le cerveau de singes. Toutefois, l'étude neurophysiologique de ces système d'accumulation chez l'homme est rare. Ce travail de thèse vise à mieux comprendre les mécanismes neuronaux de prise de décision chez l'homme dans des contextes de la vie réelle, beaucoup plus complexes que ceux utilisés chez le singe. / A perceptual decision is a deliberative process that aims to choose a categorical proposition or course of action from a set of alternatives on the basis of available sensory information. Models of perceptual decision-making assume that sensory information is accumulated to some threshold level, whence the decision terminates in a choice. The recent discovery of neural correlates of these theoretical predictions in the non-human primate brain has reinforced their validity. However, neurophysiological studies of perceptual decision-making mechanisms in humans are relatively scarce. This work aims at enhancing our understanding of the computations and neurophysiology underpinning such mechanisms in humans, through the study of decision-making contexts more complex than those used in monkey research.
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Impacto da cirurgia de epilepsia no desempenho cognitivo de pacientes com esclerose mesial temporal unilateral / Impact of epilepsy surgery on cognitive performance of patients with unilateral mesial temporal sclerosis

Humberto de Castro Lima Filho 21 November 2017 (has links)
INTRODUÇÃO: A esclerose mesial temporal (EMT) é uma das principais causas de epilepsia focal farmacorresistente. O prognóstico cirúrgico é excelente, porém pode ocorrer declínio cognitivo pós-operatório. Este estudo teve como objetivo verificar o impacto cognitivo da lobectomia temporal anterior em pacientes com EMT, levando em consideração o padrão de envolvimento eletrográfico ictal. MÉTODOS: Foram selecionados pacientes com epilepsia farmacorresistente secundária à EMT unilateral e sujeitos sem epilepsia, com idade entre 18 e 55 anos e oito ou mais anos de escolaridade. Os pacientes foram agrupados de acordo com o lado da EMT em esquerda (EMTE) e direita (EMTD). Aqueles que recusaram cirurgia foram incluídos no grupo-controle clínico e os que optaram por cirurgia foram incluídos no grupo cirúrgico. Pacientes do grupo cirúrgico foram submetidos a vídeo-EEG e teste de Wada. Pacientes com representação de linguagem atípica foram excluídos. O grupo cirúrgico foi subdividido de acordo com o padrão eletrográfico ictal determinado pelo vídeo-EEG em: envolvimento eletrográfico ictal exclusivamente ipsilateral e envolvimento eletrográfico ictal bilateral. A avaliação neuropsicológica dos pacientes foi realizada em dois momentos. Os sujeitos sem epilepsia foram avaliados apenas uma vez. Para análise estatística, foram utilizados testes paramétricos ou não paramétricos a depender da normalidade da distribuição dos dados. Os grupos foram comparados em relação a variáveis clínicas, pontuações basais nos testes neuropsicológicos e diferenças médias das pontuações entre a segunda e primeira avaliações. Também foram comparadas as pontuações médias da primeira e segunda avaliações dentro de um mesmo grupo. O grupo clínico foi utilizado para o cálculo do índice de mudança confiável (RCI). Considerou-se melhora no desempenho cognitivo escore Z > 1,645 e piora escore Z < -1,645. RESULTADOS: A análise final incluiu 65 pacientes com epilepsia e 40 sujeitos sem epilepsia. Vinte e um pacientes (nove EMTE, doze EMTD) recusaram cirurgia e foram incluídos no grupo clínico. O grupo cirúrgico foi composto por 25 pacientes com EMTE e 19 com EMTD. Dez pacientes do grupo cirúrgico com EMTE apresentaram envolvimento ictal exclusivamente ipsilateral e 15 bilateral. No grupo cirúrgico com EMTD, dez apresentaram envolvimento ictal exclusivamente ipsilateral e nove bilateral. Os pacientes com EMT apresentaram desempenho cognitivo inferior aos sujeitos sem epilepsia, sendo mais evidente comprometimento de memória nos pacientes com EMTE. A cirurgia provocou declínio de memória no grupo com EMTE e tendência de melhora em funções executivas em ambos os grupos. O envolvimento eletrográfico bilateral associou-se a menor declínio pós-operatório de memória verbal no grupo com EMTE. O envolvimento eletrográfico bilateral associou-se à piora no desempenho pós-operatório no teste de repetição de dígitos na ordem inversa no grupo com EMTD. Foi observada redução na pontuação da escala de depressão, após a cirurgia, em pacientes com EMTE e envolvimento eletrográfico ictal bilateral. CONCLUSÃO: O envolvimento eletrográfico bilateral não se associou a maior risco de declínio de memória pós-operatório, portanto, o tratamento cirúrgico não deve ser contraindicado nestes pacientes / INTRODUCTION: Mesial temporal sclerosis (MTS) is a major cause of drug-resistant focal epilepsy. Surgical prognosis is excellent, but surgery can lead to cognitive decline. The present study aimed to evaluate the impact of anterior temporal lobectomy in MTS patients, taking into account the ictal electrographic pattern. METHODS: Patients with drug-resistant epilepsy secondary to unilateral MTS and subjects without epilepsy, aged between 18 and 55 years, with eight or more education years were selected. Patients were grouped according to MTS side as left (L-MTS) or right (R-MTS). Patients who declined surgery were included as clinical controls, and those who opted for surgery were included in the surgical group. The surgical group underwent video-EEG monitoring and Wada testing. Patients with atypical language representation were excluded. According to the ictal electrographic pattern determined by video-EEG, the surgical group was subdivided as: exclusive ipsilateral electrographic ictal involvement or bilateral electrographic ictal involvement. Patients underwent neuropsychological evaluation on two occasions. Subjects without epilepsy were evaluated once. Parametric or non-parametric tests were used according to normality of data distribution. Groups were compared in relation to clinical variables, baseline neuropsychological test scores, and mean scores differences between second and first evaluations. Mean first and second evaluation scores were also compared within the same group. The clinical group data was used to calculate the reliable change index (RCI). Z-scores > 1.645 were considered improvement, and Z-scores <-1,645 as decline. RESULTS: Analysis included 65 patients with epilepsy and 40 subjects without epilepsy. Twenty-one patients (nine L-MTS, twelve R-MTS) declined surgery and were included as clinical controls. The surgical group consisted of 25 patients with L-MTS and 19 with R-MTS. Ten patients in the L-MTS surgical group presented exclusive ipsilateral ictal involvement and 15 presented bilateral involvement. In the R-MTS surgical group, ten presented exclusive ipsilateral ictal involvement and nine presented bilateral involvement. Patients with MTS had worse cognitive performance than subjects without epilepsy. L-MTS group presented more impairment in memory. Surgery lead to memory decline in the L-MTS group and to a tendency towards improvement on executive functioning in both groups. Bilateral electrographic involvement was associated with less verbal memory decline in the L-MTS group. Bilateral electrographic involvement was associated with worsening in digit span in R-MTS group and improved scores in the depression scale in L-MTS group. CONCLUSION: Bilateral electrographic involvement was not associated with a higher risk of postoperative memory decline. Epilepsy surgery should therefore not be denied to these patients
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Second Language Semantic Retrieval in the Bilingual Mind: The Case of Korean-English Expert Bilinguals

Lam, Janice Si-Man 01 November 2018 (has links)
The present study aims to explore the relationship between proficiency level and semantic retrieval in the second language. A group of Korean bilinguals who speak English with high proficiency performed semantic relatedness judgement tasks of two hundred English word pairs. Unbeknownst to the participants, half of the words in both the related and the unrelated categories contained a "hidden prime"—a common first syllable shared by the two words, if translated into Korean. Each participant's event-related potential (ERP) was recorded while reading the words. While a former study by Thierry and Wu (2007) found that Chinese-English bilinguals were affected by the hidden primes, thus causing a "N400 reduction effect" in their averaged ERP, the bilingual group of the present study was unaffected by the hidden primes. The difference between the bilingual groups' performance between Thierry and Wu's study and the present study is likely caused by the higher English proficiency of the bilingual group in the present study. This provides additional evidence supporting the Revised Hierarchical Model of semantic retrieval proposed by Kroll and Steward (1994), which suggests that increased proficiency leads to reduced reliance on the first language during second language semantic retrieval.
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The Effect of Time of Day of Chronic Exercise on Neural Response to Visual Food Cues

Davies, Jessica Taylor 01 February 2017 (has links)
This study examined the effect of an 8-week, progressive exercise intervention on neural responses, specifically N2 amplitude as a measure of inhibitory control, to pictures of food. Healthy women ages 18-44 years were randomized to a morning (AM) exercise group or evening (PM) exercise group. The AM group did moderate-to-vigorous intensity exercise on 4 days per week between 6:30 and 9:30 a.m. while the PM group had the identical volume of exercise between 6:30 and 9:30 p.m. Neural responses, eating behaviors, cardiovascular fitness outcomes, and body weight/composition were measured at baseline and after the 8-week intervention. The N2 amplitude in response to pictures of high- and low-calorie foods was assessed using electroencephalography during a go/no-go task. Dietary restraint, emotional eating, and external eating were assessed using the Dutch Eating Behavior Questionnaire. VO2peak, HRmax, and time to completion were measured during a maximal treadmill test. Body weight was measured on a digital scale, and body composition was measured using dual-energy x-ray absorptiometry. There was not a significant task (go, no-go) × group (AM, PM) × period (baseline, 8 weeks) interaction (F = 0.18; p = 0.677), but there was a main effect of exercise over 8 weeks (F = 6.26; p = 0.017) with increased N2 amplitude following the intervention. There was not a significant interaction as a function of picture type (high-calorie, low-calorie), task, group, and period (F = 0.52; p = 0.478). Changes in body weight and neural outcomes were not significantly associated with changes in eating behaviors for either group (ps < 0.05). There was a significant group × period interaction for body weight (F = 4.90; p = 0.032). Body weight increased by 0.79 ± 1.16 kg in the AM group and decreased by 0.21 ± 1.46 kg in the PM group (effect size = 0.77; CI = 0.15-1.35). There was not a significant group × period interaction for body fat percentage, total body fat or fat-free mass (ps < 0.05). When examining the main effect of exercise on cardiovascular fitness outcomes, VO2peak was not different (F = 1.80; p = 0.187), time-to-completion on treadmill increased (F = 6.51; p = 0.014), and HRmax during the treadmill test was significantly lower (F = 5.49; p = 0.025). This study suggests that 8 weeks of exercise training may increase the inhibitory response to pictures of both high- and low-calorie foods. However, time of day of exercise did not influence this response. Eight weeks of exercise training did not change self-reported dietary restraint, external eating, or emotional eating, and there was no correlation between these eating behaviors and inhibitory control. However, evening exercise was more beneficial for body weight than morning exercise. Given the novelty of this study and its results, additional studies on the influence of time of day of exercise on weight management are needed.

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