Navegando por Palavras-chave "Potenciais evocados"
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- ItemAcesso aberto (Open Access)Avaliação dos potenciais evocados relacionados a eventos (ERP-P300) em pacientes com cirrose hepática sem encefalopatia(Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE Colégio Brasileiro de Cirurgia Digestiva - CBCD Sociedade Brasileira de Motilidade Digestiva - SBMD Federação Brasileira de Gastroenterologia - FBGSociedade Brasileira de Hepatologia - SBHSociedade Brasileira de Endoscopia Digestiva - SOBED, 2008-03-01) Teodoro, Vinicius Vasconcelos [UNIFESP]; Bragagnolo Junior, Maurício; Lucchesi, Ligia Mendonça [UNIFESP]; Kondo, Mario [UNIFESP]; Tufik, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)BACKGROUND: In hepatic cirrhosis structural liver alterations occur leading to the loss of the organ functions with neuro-psychiatric consequence, as cognitive dysfunctions. One of the most effective ways of objectively evaluating cognition is to measure electrophysiological activity in the central nervous system trough event-related potentials (ERP-P300). AIM: To assess the value of the event-related potential (ERP) in order to determine cognitive disturbances in patients with liver cirrhosis and to assist in the diagnosis of minimal hepatic encephalopathy. METHODS: Fifty patients with liver cirrhosis were selected, without clinical symptoms of hepatic encephalopathy and 35 healthy volunteers, matched by sex and age. The patients were submitted to clinical-neurological and laboratorial examination. The ERP-P300 was performed by the two groups to determine cognitive disturbances. RESULTS: The study showed significant differences between the ERP-P300 latency averages of the two groups. CONCLUSION: The ERP-P300 is simple to use and depends on controllable variables. It is also easy to reproduce and, when properly used, can be useful both to determine cognitive disturbances in patients with hepatic cirrhosis and to assist in minimal hepatic encephalopathy diagnosis.
- ItemRestritoAvaliação eletrofisiológica do processamento auditivo central em mulheres no climatério(Universidade Federal de São Paulo, 2021-12-03) Oliveira, Thuany Tossato [UNIFESP]; Gil, Daniela [UNIFESP]; Silva, Ivaldo da [UNIFESP]; http://lattes.cnpq.br/9948402316193744; http://lattes.cnpq.br/6363626867862971; http://lattes.cnpq.br/6322926704062223Introdução: O climatério é considerado uma síndrome com sintomas variáveis e que afeta o organismo como um todo. Nesse período ocorre a menopausa, interrupção permanente da menstruação, reconhecida após 12 meses consecutivos de amenorréia. O climatério, pode então ser entendido como o período que precede o término da vida reprodutiva da mulher, marcado por alterações somáticas e psíquicas, e estende-se até a senilidade. Uma das alterações observadas é a queda na produção de estrogênio, que além de ser o principal hormônio reprodutor feminino, também possui ação em outros sistemas, dentre eles o nervoso. Devido ao papel do estrogênio no sistema auditivo, as mulheres no período do climatério podem sofrer distúrbios no processamento auditivo devido à diminuição da produção do hormônio, já que este tem profunda relação com o processamento de informações verbais. Com isso, a terapia hormonal, além de diminuir os sintomas da menopausa, pode ainda beneficiar as mulheres quanto aos efeitos no processamento auditivo. Para comprovar os efeitos auditivos pré e pós terapia hormonal, é necessário a avaliação do processamento auditivo central, bem como dos potenciais evocados auditivos. Objetivo: Caracterizar os potenciais evocados auditivos de curta e de longa latência em mulheres no climatério com e sem terapia hormonal. Método: A amostra foi constituída por 12 mulheres com idades entre 45 e 58 anos sem queixa auditiva. Os grupos de estudo (com terapia hormonal) e controle (sem terapia hormonal) foram compostos por seis mulheres cada. A avaliação eletrofisiológica foi constituída pela pesquisa do Potencial Evocado Auditivo de Tronco Encefálico (PEATE) e do Potencial Evocado Auditivo de Longa Latência (PEALL). Além disso, foi aplicado um questionário informal sobre fadiga. Resultados: Observou-se diferenças estatisticamente significantes para as latências absolutas das ondas III e V do potencial evocado auditivo de tronco encefálico na orelha direita e da onda I na orelha esquerda com latências menores para o grupo com terapia hormonal. Conclusão: Mulheres no climatério que fazem uso de terapia hormonal apresentam menores latências no potencial evocado auditivo de tronco encefálico do que mulheres sem terapia hormonal. Os dois grupos de mulheres não diferem quanto ao potencial evocado auditivo de longa latência e quanto à avaliação informal da fadiga.
- ItemAcesso aberto (Open Access)Estudo do potencial evocado miogênico vestibular na vertigem posicional paroxística benigna(Universidade Federal de São Paulo (UNIFESP), 2010-08-25) Dorigueto, Ricardo Schaffeln [UNIFESP]; Munhoz, Mário Sérgio Lei [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Introduction: Benign Paroxysmal Positional Vertigo (BPPV) is a highly last longing disorder. Despite being benign, it may follow a chronic and resistive course. Therefore, it may lead to serious difficulties to patients’ quality of life. The study of the performance of otoliths organs by Vestibular Evoked Myogenic Potential (VEMP) testing may be the key to understand the involvement and recurrent function in BPPV. Objective: It is to determine if there is statistically meaningful difference in the saccule-collic reflex in a Control group when compared to patients with BPPV as well as between the recurrent and non recurrent form of BPPV. Method: The transversal study by VEMP diagnostic intervention, where the Control group and patients with recurrent or non-recurrent BPPV forms went through an assessment. Results: The frequency of changes in VEMP was significantly greater in the BPPV patient group than the Control group (p<0,001). Changes were found related to the lack of response, the asymmetric index (AI) and the latencies of p13 and n23, however, just the lack of responses (p<0,001) and asymmetric index (p<0,001) results showed statistically significant difference related to the Control group. There has been no statistic difference between the recurrent and non recurrent forms of BPPV associated with VEMP result (p=0,09). Conclusion: There has been statistically significant difference in the saccule-collic reflex behavior from the group with BPPV when related to the Control group. There has been no statistically significant difference in the saccule-cholic reflex behavior between the recurrent and non recurrent form of BPPV.
- ItemAcesso aberto (Open Access)Hemorragia peri-intraventricular: estudo do efeito de supressão nas vias auditivas.(Universidade Federal de São Paulo (UNIFESP), 2018-12-07) Sousa, Elaine Colombo [UNIFESP]; Azevedo, Marisa Frasson de [UNIFESP]; http://lattes.cnpq.br/3499728717437032; http://lattes.cnpq.br/5031701812524795; Universidade Federal de São Paulo (UNIFESP)OBJECTIVE: Determine the functioning of the efferent auditory system in premature newborns with intraventricular hemorrhage. METHOD: The study group was composed of 22 newborns with intraventricular hemorrhage and the control group was composed of 22 newborns without intraventricular hemorrhage, matched to the study group for gestational age, correct gestational age and sex. The groups were submitted to the study of otoacoustic emissions evoked by a transient stimulus and suppression in otoacoustic emissions (equipment ILOv6Otodynamics Ltda®) and the study of the auditory evoked potential with and without contralateral noise (equipment SmartEPIntelligent Hearing Systems®). RESULTS: Newborns with intraventricular hemorrhage exhibited a higher occurrence of central hearing alteration as well as a greater occurrence of the absence of the suppression in otoacoustic emissions and auditory evoked potential compared to the newborns without this condition. An association was found between central hearing alteration and a lower occurrence of suppression. Agreement was found between the suppression test on otoacoustic emissions and the suppression test on latency of the auditory evoked potential. CONCLUSION: Premature newborns with intraventricular hemorrhage have a greater occurrence of functional abnormality of the afferent auditory system, which can be effectively identified through an evaluation of the suppression of otoacoustic emissions evoked by a transient stimulus and the latency in the brainstem auditory evoked potential.
- ItemAcesso aberto (Open Access)Potenciais cognitivos evocados durante a codificação de itens distintos e relacionados entre si: efeitos sobre a recordação livre(Universidade Federal de São Paulo (UNIFESP), 2006-01-27) Ruiz, Ana Maria Nogueira [UNIFESP]; Bueno, Orlando Francisco Amodeo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Rationale: In free-recall tasks there is a facilitation in recall of semantically related words inserted in the middle serial positions of lists of words with no other relations between them. This facilitation can be due to a series of undetermined cognitive processes such as: a) distinctiveness of the related items; b) activation of preexistent representations in memory; c) processes involved in the integration of related items. The present study sought to investigate the involvement of these processes in the facilitation effect employing both behavioural data and event related potential (ERP) alterations during encoding of words. Methods: Twenty-three undergraduates studied 80 fifteen-word lists in 4 sessions (20 random lists per session). The words in the lists were unrelated except for those in serial positions 7, 8, e 9 de 60 lists, resulting in 4 list types (20 of each) with: a) semantic relations (e.g. milk, cheese, butter); b) phonetic relations (e.g. sea, fee, knee); c) perceptual relations (words related by the type font); d) no relations (control lists). Free-recall was obtained after presentation of each list. ERPs were registered from Fz, Cz and Pz during encoding of words in positions 7, 8, 9 and 10. Results: Recall facilitation varied between lists (semantic> phonetic> perceptual > control). ERPs showed modulations of components identified as P300, N400 and another late positive component (LPC) that varied according to type of relation and electrode location. Among perceptually related words, only that in the 7th serial position was more recalled than in the control list and it led to a positivity that corresponded to a P300. In the 8th and 9th words in the lists with semantic and phonetic relations the N400 was less negative than in control lists but did nor reflect the recall pattern (semantic > phonetic). An LPC occurred only in the 8th word in the semantic lists at FZ and in the 9th in all electrodes in both lists with semantic and phonetic relations which reflected the recall pattern. Conclusion: Results suggest that semantic facilitation effects can be attributed to different processes that occur together at encoding of related stimuli and that are not only due to P300 changes triggered by distinctiveness. P300 amplitude predicted recall only of single distinct items. When there was an opportunity of grouping two or three items such as in the semantic and phonetic lists, N400 and LPC participated in the facilitation effect.