31 research outputs found

    From sleep spindles of natural sleep to spike and wave discharges of typical absence seizures: is the hypothesis still valid?

    Get PDF
    The temporal coincidence of sleep spindles and spike-and-wave discharges (SWDs) in patients with idiopathic generalized epilepsies, together with the transformation of spindles into SWDs following intramuscular injection of the weak GABAA receptor (GABAAR) antagonist, penicillin, in an experimental model, brought about the view that SWDs may represent ‘perverted’ sleep spindles. Over the last 20 years, this hypothesis has received considerable support, in particular by in vitro studies of thalamic oscillations following pharmacological/genetic manipulations of GABAARs. However, from a critical appraisal of the evidence in absence epilepsy patients and well-established models of absence epilepsy it emerges that SWDs can occur as frequently during wakefulness as during sleep, with their preferential occurrence in either one of these behavioural states often being patient dependent. Moreover, whereas the EEG expression of both SWDs and sleep spindles requires the integrity of the entire cortico-thalamo-cortical network, SWDs initiates in cortex while sleep spindles in thalamus. Furthermore, the hypothesis of a reduction in GABAAR function across the entire cortico-thalamo-cortical network as the basis for the transformation of sleep spindles into SWDs is no longer tenable. In fact, while a decreased GABAAR function may be present in some cortical layers and in the reticular thalamic nucleus, both phasic and tonic GABAAR inhibitions of thalamo-cortical neurons are either unchanged or increased in this epileptic phenotype. In summary, these differences between SWDs and sleep spindles question the view that the EEG hallmark of absence seizures results from a transformation of this EEG oscillation of natural sleep

    Correlação entre o perfil do sono e o comportamento em indivíduos com transtorno específico da aprendizagem

    No full text
    RESUMO Objetivo Correlacionar o sono e o comportamento em indivíduos com transtorno específico da aprendizagem. Método Na análise do sono, foram utilizados o Questionário de Hábitos Gerais de Sono, o Diário de Sono e a Escala de Distúrbios do Sono em Crianças (EDSC) e, para análise do comportamento, foi utilizado o Child Behavior Checklist (CBCL). Resultados 65,5% dos indivíduos com transtorno específico de aprendizagem apresentaram indicativo de distúrbios de sono, sendo os mais frequentes os distúrbios de transição sono-vigília e escores totais para distúrbios de sono acima do aceitável. Além disso, os indivíduos com transtorno específico de aprendizagem apresentaram maior latência de sono que o respectivo grupo controle. Quanto ao comportamento, 72,4% dos indivíduos com transtorno específico de aprendizagem apresentaram quadro clínico de problemas comportamentais. No grupo controle, nenhum dos participantes apresentou indicativo de problemas de sono ou comportamento. No grupo transtorno específico de aprendizagem, os distúrbios de sono encontrados apresentaram correlação com os problemas comportamentais. Conclusão Indivíduos com transtorno específico da aprendizagem apresentaram altos índices de distúrbios de sono e alterações comportamentais. Quanto piores os distúrbios de sono, piores foram os aspectos comportamentais dos indivíduos com transtorno específico da aprendizagem

    Language Lateralization in Children Aged 10 to 11 Years: A Combined fMRI and Dichotic Listening Study

    Get PDF
    OBJECTIVE: The aims of this study were to develop and assess a method to map language networks in children with two auditory fMRI protocols in combination with a dichotic listening task (DL). The method is intended for pediatric patients prior to epilepsy surgery. To evaluate the potential clinical usefulness of the method we first wanted to assess data from a group of healthy children. METHODS: In a first step language test materials were developed, intended for subsequent implementation in fMRI protocols. An evaluation of this material was done in 30 children with typical development, 10 from the 1(st), 4(th) and the 7(th) grade, respectively. The language test material was then adapted and implemented in two fMRI protocols intended to target frontal and posterior language networks. In a second step language lateralization was assessed in 17 typical 10–11 year olds with fMRI and DL. To reach a conclusion about language lateralization, firstly, quantitative analyses of the index data from the two fMRI tasks and the index data from the DL task were done separately. In a second step a set of criteria were applied to these results to reach a conclusion about language lateralization. The steps of these analyses are described in detail. RESULTS: The behavioral assessment of the language test material showed that it was well suited for typical children. The results of the language lateralization assessments, based on fMRI data and DL data, showed that for 15 of the 17 subjects (88%) a conclusion could be reached about hemispheric language dominance. In 2 cases (12%) DL provided critical data. CONCLUSIONS: The employment of DL combined with language mapping using fMRI for assessing hemispheric language dominance is novel and it was deemed valuable since it provided additional information compared to the results gained from each method individually
    corecore