1,720,966 research outputs found
Sleep EEG oscillations in neurodevelopmental disorders without intellectual disabilities
No full textNeurodevelopmental disorders (NDDs) are often characterised by sleep problems, and recent evidence indicates alterations of the sleep electroencephalographic (EEG) oscillations in these patients. Sleep microstructure plays a crucial role in cognitive functioning and brain maturation. In this view, modifications in sleep EEG oscillations in NDDs could further impair the cognitive maturation process in these patients. We provide an overview of sleep microstructure alterations observed in three NDDs without intellectual disabilities (attention-deficit/hyperactivity disorder, high-functioning autism/Asperger syndrome and developmental dyslexia) and their relationships with the disorders' phenomenology. For each NDD, we discuss empirical evidence of altered EEG oscillations, and we consider their interaction with patients' cognitive and behavioural functioning, with the aim to elucidate their functional meaning. We highlight the limits of the present literature and propose possible future directions while underlining the clinical relevance of the research in this field. Beyond confirming the importance of sleep management in atypically developing children, the review findings suggest that sleep EEG oscillations in NDDs could become a target for specific clinical intervention
Advances in understanding the relationship between sleep and attention deficit-hyperactivity disorder (ADHD)
Full text linkAbstract: Starting from the consolidated relationship between sleep and cognition, we reviewed the
available literature on the association between Attention Deficit-Hyperactivity Disorder (ADHD) and
sleep. This review analyzes the macrostructural and microstructural sleep features, following the
Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria (PRISMA).We included
the polysomnographic studies published in the last 15 years. The results of macrostructural
parameters are mixed. Almost half of the 18 selected investigations did not find dierences between
sleep architecture of children with ADHD and controls. Five studies observed that children with
ADHD show a longer Rapid Eye Movement (REM) sleep duration than controls. Eight studies
included microstructural measures. Remarkable alterations in sleep microstructure of ADHD are
related to slow wave activity (SWA) and theta oscillations, respectively, during Non-REM (NREM)
and REM sleep. Specifically, some studies found higher SWA in the ADHD group than controls.
Similarly, higher theta activity appears to be detrimental for memory performance and inhibitory
control in ADHD. These patterns could be interpreted as a maturational delay in ADHD. Also, the
increased amount of these activities would be consistent with the hypothesis that the poor sleep
could imply a chronic sleep deprivation in children with ADHD, which in turn could aect their
cognitive functioning
The heritability of the human K-complex. A twin study
No full textSleep electroencephalogram (EEG) has a trait-like nature. Several findings highlighted the heritability of spectral power in specific frequency ranges and sleep spindles during NREM sleep. However, a genetic influence on the K-complex (KC), one of the electrophysiological hallmarks of NREM sleep, has never been assessed. Here, we investigated the heritability of the KC detected during NREM stage 2 comparing 10 monozygotic (MZ) and 10 dizygotic (DZ) twin pairs. Genetic variance analysis (GVA) and Intraclass Correlation Coefficients (ICCs) were performed to assess the genetic effect and within-pair similarity for KC density, amplitude, and for the area-under-the-curve (AUC) of the KC average waveform at Fz, Cz and Pz scalp locations. Moreover, cluster analysis was performed on the KC average waveform profile. We observed a significant genetic effect on KC AUC at Cz and Pz, and on amplitude at Pz. Within-pair similarity (ICCs) was always significant for MZ twins except for KC density at Fz, while DZ twins always exhibited ICCs below the significance threshold, with the exception of density at Pz. The largest differences in within-pair similarity between MZ and DZ groups were observed again for AUC at Cz and Pz. MZ pairs accurately clustered for the KC average waveform with a higher frequency (successful clustering rate for MZ pairs: Fz=60%; Cz=80%; Pz=90%) compared to DZ pairs (successful clustering rate for DZ pairs: Fz=10%; Cz=10%; Pz=none). Our results suggest the existence of a genetic influence on the human KC, particularly related to its morphology and maximally observable in central and parietal location
Advances in Understanding the Relationship between Sleep and Attention Deficit-Hyperactivity Disorder (ADHD)
No full textStarting from the consolidated relationship between sleep and cognition, we reviewed the available literature on the association between Attention Deficit-Hyperactivity Disorder (ADHD) and sleep. This review analyzes the macrostructural and microstructural sleep features, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria (PRISMA). We included the polysomnographic studies published in the last 15 years. The results of macrostructural parameters are mixed. Almost half of the 18 selected investigations did not find differences between sleep architecture of children with ADHD and controls. Five studies observed that children with ADHD show a longer Rapid Eye Movement (REM) sleep duration than controls. Eight studies included microstructural measures. Remarkable alterations in sleep microstructure of ADHD are related to slow wave activity (SWA) and theta oscillations, respectively, during Non-REM (NREM) and REM sleep. Specifically, some studies found higher SWA in the ADHD group than controls. Similarly, higher theta activity appears to be detrimental for memory performance and inhibitory control in ADHD. These patterns could be interpreted as a maturational delay in ADHD. Also, the increased amount of these activities would be consistent with the hypothesis that the poor sleep could imply a chronic sleep deprivation in children with ADHD, which in turn could affect their cognitive functioning
Psychometric and factorial validity of the International Adjustment Disorder Questionnaire (IADQ) in an Italian sample: A validation and prevalence estimate study
No full textIntroductionAdjustment disorder (AjD) is a is a maladaptive emotional or behavioural reaction to a stressful event or change in a person's life. Compared to other previously validated tools, the International Adjustment Disorder Questionnaire (IADQ) stands out as one of the most reliable and handy one for AjD.Since no homologous instrument exists now, in this study, we aimed to validate an Italian version of the IADQ. MethodsTwenty-one thousand two hundred and six subjects (80.4% females) during the initial stages of the SARS-CoV-2 pandemic were recruited. We conducted a confirmatory factor analysis (CFA), testing two latent models, a monofactorial and a bifactorial one. Concurrent validity by correlating the total and the two factors' scores with measures of depression, anxiety and post-traumatic stress was then estimated. We finally estimated the rates of AjD among the population, and a binary logistic regression was conducted to analyse the predictors of such disorder. ResultsCFA showed a bifactorial validity, with both excellent incremental and comparative fit indices. The IADQ scores correlated strongly with symptoms of depression, anxiety and stress. In the Italian sample, the prevalence of probable AjD was 8.23%. Female gender, being engaged, widowed and having COVID-19-related stressors resulted as significant independent risk factors for AjD. ConclusionsIADQ is an easy-to-use, brief and psychometrically sound self-report measure for AjD. Thus, it may be considered a reliable tool for both research and clinical settings. To the best of our knowledge, our study reported for the first time the prevalence of AjD during COVID-19 pandemic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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