1,720,978 research outputs found
Are stroke cases affected by sleep disordered breathings all the same?
No full textSleep disordered breathings (SDB) worsens the clinical prognosis of stroke patients. Continuous positive airway pressure (CPAP) is a promising effective treatment. Unfortunately, not all patients are compliant with CPAP, suggesting that it is not appropriate for all patients with obstructive sleep apnoea (USA) after stroke. People with the highest likelihood of benefiting have to be identified. We present a classification of cases with stroke and SDB to be adopted in order to identify the best responders to CPAP treatment. We propose to classify patients in four subgroups: (1) patients who terminate the apnoea by arousing from sleep; these cases are those affected either by an anatomical or a functional obstruction of upper airways that may precede or are the consequence of stroke; (2) cases that alternate OSA to central sleep apnoea (CSA) cause of an altered loop gain; (3) cases in whom ischemic damages have altered the sleep microstructure (CAP); (4) cases that manifest a CSA as the direct consequence of stroke on the central neuronal drive to breath. So far, no study has investigated the consequences of stroke on sleep microstructure. In order to better elucidate these relationships, when reviewing the PSG tracings of stroke patients, the microstructure of sleep should be systematically analysed. (C) 2014 Elsevier Ltd. All rights reserved.Seep disordered breathings (SDB) affects outcome of stroke patients, consequently continuous positive airway
pressure (CPAP) treatment is largely justified. Unfortunately, not all are compliant with CPAP, suggesting that it is not
appropriate for everyone with OSA after stroke. People with the highest likelihood of benefiting have to be identified.
We present one subdivision of cases with stroke and SDB to be adopted in order to identify possible best responders to
CPAP treatment. Four different subgroups are proposed: 1. patients who terminate the apnoea by arousing from sleep;
these cases are those affected either by an anatomical or a functional obstruction of upper airways that precede or else
are the consequence of stroke on upper airways; 2. cases that alternate obstructive sleep apnoea (OSA) to central sleep
apnoea (CSA) cause of a loop gain >1; 3. cases in who ischemic damaging processes have altered sleep microstructure
(CAP). Increase in the number of CAP’s phases B can caus
Cerebellar damage impairs detection of somatosensory input changes. A somatosensory mismatch-negativity study
No full textSeveral recent studies support the view that the cerebellum's contribution to sensory processing is not limited to movement regulation. In a previous paper (Restuccia et al. 2001)) we showed that the cerebellum influences somatosensory input processing at very early stages. The present study was aimed at verifying whether an analogous influence is also exerted at higher levels. For some time it has been known that in the auditory modality a specific Event-Related Potential (ERP), i.e., Mismatch Negativity (MMN), reflects preattentive detection of changes in the incoming stimulus by comparing the new stimulus with sensory memory traces. To test the cerebellar influence on the processing of incoming somatosensory stimuli we first verified whether the electrical stimulation of fingers, according to an "oddball" paradigm within a stimulus-ignored condition, was able to elicit event-related components specifically linked to the preattentive detection of change. We analysed scalp responses obtained from eight healthy volunteers during frequent and rare electrical stimulation of the first and fifth finger of the left hand respectively. To ensure that responses to deviant stimuli were due to changes in detection mechanisms, rather than to activation of new afferents, we also analysed responses to rare stimulation alone (“standard-omitted” condition). The "oddball" stimulation was able to elicit a parieto-occipital extra negativity that was different in scalp distribution and latency from the N140 response to the “standard-omitted” stimulation. We considered that this response was related to changes in detection mechanisms and labelled it Somatosensory Mismatch Negativity (S-MMN). When the same procedure was applied to six patients with unilateral cerebellar lesions we found that the S-MMN was clearly abnormal after stimulation of the affected hand (ipsilateral to the affected cerebellar hemisphere). Earlier ERPs, as well as ERPs elicited during the “standard-omitted” condition, were fully normal. Present data indicate that cerebellar processing is involved in preattentive detection of somatosensory input changes. In conclusion, this study demonstrates the reliability of S-MMN recordings and indicates that subjects with cerebellar damage may be impaired in the cortical processing incoming somatosensory inputs.Several recent studies support the view that the cerebellum's contribution to sensory processing is not limited to movement regulation. In a previous paper (Restuccia et al. 2001)) we showed that the cerebellum influences somatosensory input processing at very early stages. The present study was aimed at verifying whether an analogous influence is also exerted at higher levels. For some time it has been known that in the auditory modality a specific Event-Related Potential (ERP), i.e., Mismatch Negativity (MMN), reflects preattentive detection of changes in the incoming stimulus by comparing the new stimulus with sensory memory traces. To test the cerebellar influence on the processing of incoming somatosensory stimuli we first verified whether the electrical stimulation of fingers, according to an "oddball" paradigm within a stimulus-ignored condition, was able to elicit event-related components specifically linked to the preattentive detection of change. We analysed scalp responses
Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study
No full textThe aim of the present study was to explore the
modifications of scalp EEG power spectra and EEG connectivity
during the autobiographical memory test (AM-T)
and during the retrieval of an autobiographical event (the
high school final examination, Task 2). Seventeen healthy
volunteers were enrolled (9 women and 8 men, mean age
23.4 ± 2.8 years, range 19–30). EEG was recorded at
baseline and while performing the autobiographical memory
(AM) tasks, by means of 19 surface electrodes and a
nasopharyngeal electrode. EEG analysis was conducted by
means of the standardized LOw Resolution Electric
Tomography (sLORETA) software. Power spectra and
lagged EEG coherence were compared between EEG
acquired during the memory tasks and baseline recording.
The frequency bands considered were as follows: delta
(0.5–4 Hz); theta (4.5–7.5 Hz); alpha (8–12.5 Hz); beta1
(13–17.5 Hz); beta2 (18–30 Hz); gamma (30.5–60 Hz).
During AM-T, we observed a significant delta power
increase in left frontal and midline cortices (T = 3.554;
p\0.05) and increased EEG connectivity in delta band in
prefrontal, temporal, parietal, and occipital areas, and for
gamma bands in the left temporo-parietal regions
(T = 4.154; p\0.05). In Task 2, we measured an
increased power in the gamma band located in the left posterior midline areas (T = 3.960; p\0.05) and a significant
increase in delta band connectivity in the prefrontal,
temporal, parietal, and occipital areas, and in the
gamma band involving right temporo-parietal areas
(T = 4.579; p\0.05). These results indicate that AM
retrieval engages in a complex network which is mediated
by both low- (delta) and high-frequency (gamma) EEG
bands
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
