1,721,114 research outputs found
To support safe provision of mechanical thrombectomy services for patients with acute ischaemic stroke: 2021 consensus guidance from BASP, BSNR, ICSWP, NACCS, and UKNG
No full textForewordThis document supersedes the existing professional multisociety consensus guidance published in 2015.1 It has been produced in order to respond to the considerable volume of relevant new high-quality trial evidence that has become available since September 2015. It should be emphasised that this document remains applicable to all constituent nations of the UK, and thus, deliberately avoids the use of acronyms or reference to structures that do not pertain to all four nations wherever possible. The guidance was developed (and is now updated) to aid thrombectomy delivery by describing the key requirements for an endovascular stroke therapy service, including the service support requirements and basic performance standards that should be met. Indeed, it substantially influenced the commissioning of thrombectomy by NHS England in 2017.The standards guidance is intended to support all medical staff and allied health professionals who directly contribute to the delivery of thrombectomy. Both editions of the standards guidance were drawn up through consensus by a working party of appointed representatives from the British Association of Stroke Physicians, the British Society of Neuroradiologists, the Intercollegiate Stroke Working Party, the Neuroanaesthesia and Critical Care Society and the United Kingdom Neurointerventional Group. Drafts were modified in response to review by committees in each society or group. This document draws on publications from other organisations, but is intended to be (whole) UK-focussed, practical, and pathway-orientated. The guidance is a consensus on the minimum service standards required to support a thrombectomy service in terms of specialist staffing/skill mix and the organisation of services. These standards are required in order to minimise the inherent risks related to the mechanical thrombectomy (MT) care pathway and to account for new data from the key trials.It is recommended that acute stroke thrombectomy should only be undertaken within specialist stroke centres that fulfil agreed standards of care for infrastructure, information technology, imaging equipment, staff, and process. Every centre where such procedures are undertaken has a duty to ensure that safe arrangements are in place. The evidence for thrombectomy efficacy may not be generalisable outside neuroscience/experienced comprehensive stroke centres2 and broad MT implementation without reference to evidence-based professional standards may risk lower individual and population treatment benefit and result in more patient harm
Association between Striatal Brain Iron Deposition, Microbleeds and Cognition 1 Year After a Minor Ischaemic Stroke
Full text linkValdes Hernandez, Maria Del C Case, Tessa Chappell, Francesca M Glatz, Andreas Makin, Stephen Doubal, Fergus Wardlaw, Joanna M eng BROD.FID3668413/Mrs Gladys Row Fogo Charitable Trust 088134/Z/0/Wellcome Trust/United Kingdom PHC-03-15, project No 666881, 'SVDs@Target'/Horizon 2020 16 CVD 05/Fondation Leducq Switzerland Int J Mol Sci. 2019 Mar 14;20(6). pii: ijms20061293. doi: 10.3390/ijms20061293.Peer reviewe
Nonfocal symptoms of cerebral small vessel disease
Full text linkCerebral small vessel disease (SVD) is highly prevalent in the general
population, increases with advancing age, and is a common cause of stroke
and dementia. SVD affects multiple clinical domains and manifests on
neuroimaging primarily as white matter hyperintensities (WMH), subcortical
infarcts, lacunes, perivascular spaces, and microbleeds. Apart from stroke and
dementia, SVD was previously thought to be clinically ‘silent’ but it is becoming
apparent from cross-sectional studies that SVD is accompanied by
neuropsychiatric, cognitive, and gait symptoms that do not meet the current
clinical lexicon for stroke or dementia. Identifying earlier clinical markers of
brain damage is essential for identifying patients for SVD treatment trials. We
aimed to track and characterise whether subtle nonfocal symptoms are
longitudinally associated with SVD lesion progression on brain MRI.
We conducted a literature review of all SVD clinical features and a systematic
review and meta-analysis of SVD-associated neuropsychiatric and cognitive
features. We recruited patients with recent non-disabling ischaemic stroke,
performed diagnostic MRI, and questioned participants and informants about
neuropsychiatric, cognitive and gait symptoms. We repeated MRI and
subjective symptom assessments at 3-6 monthly intervals for 12 months,
longitudinally assessing WMH volume change and incident infarcts. We also
analysed combined functional and cognitive associations with SVD
progression in a separate stroke population. Finally, we assessed
neuropsychiatric symptom-lesion associations in cognitively impaired and
older adult populations.
In our systematic review and meta-analysis, we found small but important
associations between SVD severity and apathy, fatigue, and delirium, but not
with subjective memory complaints, while anxiety and other neuropsychiatric
symptoms were inconclusive. In 203 patients followed up for one year after a
stroke (55% lacunar/45% cortical), we found that incident infarcts occur in 20%
of patients, are mostly subcortical, co-associate with depression and brain fog,
and there were trends towards associations with fatigue, falls, unsteadiness,
episodes of confusion, and informant-reported cognitive and functional
decline. We identified that that worse baseline WMH are associated with falls,
apathy and brain fog, worse six-month WMH with falls and unsteadiness, and
worse 12-month WMH with a trend towards falls. We found that longitudinal
WMH progression is associated with falls and brain fog, with trends towards
associations with worsening informant-reported neuropsychiatric symptoms
and subjective memory complaints. In 264 separate stroke patients, we
identified that one-year, but not baseline, WMH volumes associate strongly
with contemporaneous cognitive scores, and co-varying longitudinal
worsening of cognition and function post-stroke is associated with increasing
WMH volumes. We found that worsening neuropsychiatric symptoms are
associated with WMH progression in a cognitively impaired population. We
established that in an older population, apathy independently associates with
longitudinal WMH progression, while depression, anxiety, and subjective
memory complaints do not.
Overall, these findings highlight the existence of a potential clinical syndrome
for identifying future SVD progression in high-risk patients. SVD progression
is dynamic and can progress rapidly. These results support a need to clarify
the prevalence of the SVD syndrome in the general population and to develop
clinical prediction models to guide whether treatments could be trialled in
individuals who are at high risk for SVD progression
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
Do retinal microvascular abnormalities shed light on the pathophysiology of lacunar stroke?
Full text linkBackground. Lacunar strokes account for 25% of all ischaemic stroke but the exact
nature of the causative cerebral small vessel abnormality remains unknown.
Pathological studies are technically difficult and brain imaging cannot adequately
characterise the cerebral small vessels. The retinal blood vessels are of similar size
and physiology to the cerebral small vessels and may act as a surrogate marker for
these cerebral small vessels. We therefore investigated retinal microvascular
abnormalities in lacunar stroke.
Methods. We performed a systematic review of retinal microvascular abnormalities
in lacunar stroke to clarify associations and identify where further research was
required. We then established a cohort of patients presenting with lacunar stroke
with cortical stroke controls to investigate differences in retinal microvascular
abnormalities between stroke subtypes. All patients had MRI brain at presentation
and digital retinal photography of both eyes. We investigated the prevalence of
retinopathy (hard and soft exudates or haemorrhages/microaneurysms), focal
arteriolar narrowing and arteriovenous nicking . We developed, validated and used
novel semi-automated techniques for measuring retinal arteriolar and venular widths,
retinal arteriolar geometry (branching co-efficients (change in arteriolar cross
sectional area across a bifurcation) and branching angles) and fractal dimensions
(reflecting branching complexity) of the vasculature. We also assessed MRI
parameters in lacunar stroke. We used multivariable analysis to correct for baseline
imbalances in vascular risk factors.
Results. From the systematic review we demonstrated that retinal microvascular
abnormalities are associated with incident and prevalent stroke but that in general,
strokes were inadequately characterised and there were no data regarding retinal
microvascular abnormalities in ischaemic stroke subtypes. We recruited 253
patients, 129 lacunar strokes and 124 cortical strokes, mean age 68 years. We found
no difference in the prevalence of retinopathy, arteriovenous nicking, focal arteriolar
narrowing or arteriolar widths between lacunar and cortical stroke subtypes. We
found that venules were wider in lacunar stroke. We found no differences in
arteriolar branching co-efficients or arteriolar branching angles between lacunar and
cortical strokes but found that deep white matter white matter hyperintensities on
MRI were associated with increased branching co-efficients and periventricular
white matter hyperintensities associated with decreased branching co-efficients. We
found that the fractal dimension of the vascular tree was decreased in lacunar stroke.
Furthermore we found that enlarged perivascular spaces on MRI are associated with
lacunar stroke and white matter disease.
Conclusions. We have clearly demonstrated that retinal microvascular abnormalities
differ between lacunar and cortical stroke suggesting that a distinct small vessel
vasculopathy may cause lacunar stroke. We have also identified MR markers of
lacunar stroke. These results suggest that venular disease (a hitherto underresearched
area) may play a role in the pathophysiology of lacunar stroke. Retinal
microvascular abnormalities can act as markers for cerebral small vessel disease. We
plan collaborative analyses with colleagues who have performed similar studies to
further assess retinal abnormalities in lacunar stroke
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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