Unilateral spatial neglect: a review over symptoms, frequency diagnosis and prognosis

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenUnilateral spatial neglect is a disorder commonly encountered after hemisphere stroke, most often in the right hemisphere. Neglect patients fail to attend and respond to stimuli presented on the side of space opposite to the brain lesion. Neglect implies a complex dysfunction in the co-action between perception, motor behavior and the environment where the patients attentive capacities and the environmental space are of special importance. Patients difficulties can be seen in that they do not eat from the left side of the plate or omit words to the left when asked to read. Commonly patients do not have a complete insight into their neglect problems. Neglect in stroke patients has been associated with poor outcome on functional activities. Signs of neglect are not always obvious but can be explored and assessed quickly by bedside neuropsychological testing. Neglect is often more unclear to an observer than, e.g. if a patient suffers from paresis or aphasia. Education for patients, their relatives and others are therefore important.Gaumstol er tiltölulega algeng truflun sem hlýst af heilaskaða, einkum heilablóðfalli í hægra heilahveli. Það kemur fram í því að sjúklingur gefur umhverfi og hlutum til gagnstæðrar áttar við heilaskaðan ónógan gaum og bregst ekki við því sem gerist til þeirrar áttar. Gaumstol felur í sér flókna röskun á samspili skynjunar, hreyfingar og umhverfis sjúklings þar sem athygli hans og rýmið sem umlykur hann skiptir miklu máli. Vandi sjúklings getur verið að hann borðar einungis af hægri hlið disks við máltíðir og les einungis orð í setningum sem eru til hægri við miðju. Oft hafa sjúklingar ekki fullt innsæi í eigin vanda og hjá sjúklingum með heilablóðfall dregur gaumstol úr batalíkum. Gaumstol er ekki alltaf augljóst en til eru fljótleg próf sem má beita til frekari glöggvunar og staðfestingar á einkennum sjúklinga. Gaumstol og afleiðingar þess eru oft óljósari en til að mynda lamanir og málstol og því er gildi greiningar og fræðslu fyrir sjúklinga, aðstandendur og aðra mikilvæg

Unilateral neglect: a review of causes, anatomical localization, theories and interventions

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenUnilateral neglect is usually caused by right hemisphere damage from stroke, leading to difficulties in attending to stimuli in the left perceptual hemifield. As an example, a patient suffering from neglect may read only the right part of a word or the right part of sentences, or eat only from the right side his plate. Neglect is more common, and most often more severe, following infarcts in the right hemisphere than the left. Brain damage leading to neglect usually involves infarcts in the inferior parietal lobe, temporo-parietal junction and/or the superior temporal lobe. Most theories of the nature of neglect assume that neglect involves dysfunctional attentional mechanisms. Increased understanding of neglect has led to the development of several effective therapeutic interventions, where prism adaptation has received the most attention in recent years. This article reviews brain damage in neglect, theories of neglect, therapeutic methods for neglect and their possible future developments.Gaumstol er skynröskun í kjölfar heilaskemmda, oftast vegna heilablóðfalls og lýsir sér að jafnaði þannig að sjúklingur tekur ekki eftir eða bregst ekki við því sem á sér stað til vinstri. Þetta getur komið fram í því að sjúklingur les aðeins hægri helming orðs eða setninga, lítur til hægri þegar einhver gengur framhjá vinstra megin við hann, eða borðar einungis af hægri helmingi disks síns. Gaumstol má oftast rekja til skemmda í neðri hluta hvirfilblaðs, á mótum hnakka- og gagnaugablaðs, eða í efstu gagnaugablaðsfellingu. Ýmsar kenningar hafa verið settar fram til skýringar á gaumstoli og í þeim flestum er gert ráð fyrir að um einhvers konar truflun á athygliskerfum sé að ræða. Aukinn skilningur á eðli gaumstols hefur virkað sem hvati að þróun meðferðarleiða þar sem strendingsaðlögun hefur vakið hvað mesta athygli á síðustu árum. Hér verður fjallað um heilaskemmdir, kenningar og meðferðarúrræði gaumstols

The Flexible Group Spatial Keyword Query

We present a new class of service for location based social networks, called the Flexible Group Spatial Keyword Query, which enables a group of users to collectively find a point of interest (POI) that optimizes an aggregate cost function combining both spatial distances and keyword similarities. In addition, our query service allows users to consider the tradeoffs between obtaining a sub-optimal solution for the entire group and obtaining an optimimized solution but only for a subgroup. We propose algorithms to process three variants of the query: (i) the group nearest neighbor with keywords query, which finds a POI that optimizes the aggregate cost function for the whole group of size n, (ii) the subgroup nearest neighbor with keywords query, which finds the optimal subgroup and a POI that optimizes the aggregate cost function for a given subgroup size m (m <= n), and (iii) the multiple subgroup nearest neighbor with keywords query, which finds optimal subgroups and corresponding POIs for each of the subgroup sizes in the range [m, n]. We design query processing algorithms based on branch-and-bound and best-first paradigms. Finally, we provide theoretical bounds and conduct extensive experiments with two real datasets which verify the effectiveness and efficiency of the proposed algorithms.Comment: 12 page

Conversion disorder - review

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenIn modern medicine the term "functional symptoms" is usually used to refer to symptoms where an organic cause cannot be found. Studies have shown that up to half of all patients consulting their family physician and approximately one third of all those attending neurology outpatient clinics present with such symptoms. These patients commonly go between doctors, repeatedly undergo unnecessary tests, even surgery, and various drugs are tried with limited success. These problems tend to be prolonged and greatly reduce the quality of life for the patients involved. Both the DSM IV and ICD 10 classifications include a group for the so-called medically unexplained disorders. Among these disorders is conversion disorder where patients present with neurological symptoms, affecting motor or sensory function, but with no neurological explanation. Here we provide an overview of the current ideas on the aetiology, diagnosis, treatment and prognosis of conversion disorder.Í nútímalæknisfræði er oft talað um starfrænar truflanir þegar vísað er til einkenna sem ekki finnst vefræn skýring á. Rannsóknir hafa sýnt að allt að helmingur sjúklinga sem leitar sér læknisaðstoðar hjá sérfræðingum í heimilislækningum og um þriðjungur allra sjúklinga sem sækja til taugalækna utan spítala hafa slík einkenni. Þessir sjúklingar ganga oft á milli lækna og undirgangast óþarfa rannsóknir og meðferðir með litlum árangri. Vandinn getur orðið langvinnur og haft í för með sér færniskerðingu og minnkuð lífsgæði. Til er flokkun í bæði DSM IV og ICD 10 greiningarkerfunum sem inniheldur raskanir er fela í sér líkamleg einkenni þar sem ekki er hægt að sýna fram á vefræna orsök. Til þessa hóps raskana telst hugbrigðaröskun þar sem einstaklingar hafa einkenni frá taugakerfinu á borð við lamanir og skyntruflanir án þess að vefræn orsök finnist. Hér verður veitt yfirlit yfir nútímahugmyndir um orsök, greiningu, meðferð og horfur hugbrigðaröskunar

Allocentric neglect strongly associated with egocentric neglect.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.Following brain injury, many patients experience egocentric spatial neglect, where they fail to respond to stimuli on the contralesional side of their body. On the other hand, allocentric, object-based neglect refers to the symptom of ignoring the contralesional side of objects, regardless of the objects' egocentric position. There is an established tradition for considering these two phenomena as both behaviorally and anatomically dissociable. However, several studies and some theoretical work have suggested that these rather reflect two aspects of a unitary underlying disorder. Furthermore, in a recent large study Yue et al. [Archives of Physical Medicine and Rehabilitation 93 (2012) 156] reported that acute allocentric neglect is only observed in cases where substantial egocentric neglect is also present. In a new sample of right hemisphere stroke patients, we attempted to control for potential confounds by using a novel continuous measure for allocentric neglect (in addition to a recently developed continuous measure for egocentric neglect). Our findings suggest a strong association between egocentric and allocentric neglect. Consistent with the work of Yue et al. (2012), we found allocentric behavioral deficits only in conjunction with egocentric deficits as well as a large corresponding overlap for the anatomical regions associated with egocentric and with allocentric neglect. We discuss how different anatomical and behavioral findings can be explained in a unified physiologically plausible framework, whereby allocentric and egocentric effects interact.National Institutes of Health NS054266 DC009571 Deutsche Forschungsgemeinschaft KA 1258/10-1 HA 5839/3-1 PAK 270/

Bulk Insertions into xBR+ -trees

Bulk insertion refers to the process of updating an existing index by inserting a large batch of new data, treating the items of this batch as a whole and not by inserting these items one-by-one. Bulk insertion is related to bulk loading, which refers to the process of creating a non-existing index from scratch, when the dataset to be indexed is available beforehand. The xBR + -tree is a balanced, disk-resident, Quadtree-based index for point data, which is very efficient for processing spatial queries. In this paper, we present the first algorithm for bulk insertion into xBR+ -trees. This algorithm incorporates extensions of techniques that we have recently developed for bulk loading xBR+ -trees. Moreover, using real and artificial datasets of various cardinalities, we present an experimental comparison of this algorithm vs. inserting items one-by-one for updating xBR+ -trees, regarding performance (I/O and execution time) and the characteristics of the resulting trees. We also present experimental results regarding the query-processing efficiency of xBR+ -trees built by bulk insertions vs. xBR+ -trees built by inserting items one-by-one

Atrial fibrillation is associated with reduced brain volume and cognitive function independent of cerebral infarcts.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Atrial fibrillation (AF) has been associated with cognitive decline independent of stroke, suggesting additional effects of AF on the brain. We aimed to assess the association between AF and brain function and structure in a general elderly population.This is a cross-sectional analysis of 4251 nondemented participants (mean age, 76 ± 5 years) in the population-based Age, Gene/Environment Susceptibility-Reykjavik Study. Medical record data were collected for the presence, subtype, and time from first diagnosis of AF; 330 participants had AF. Brain volume measurements, adjusted for intracranial volume, and presence of cerebral infarcts were determined with magnetic resonance imaging. Memory, speed of processing, and executive function composites were calculated from a cognitive test battery. In a multivariable linear regression model, adjustments were made for demographic factors, cardiovascular risk factors, and cerebral infarcts.Participants with AF had lower total brain volume compared with those without AF (P<0.001). The association was stronger with persistent/permanent than paroxysmal AF and with increased time from the first diagnosis of the disease. Of the brain tissue volumes, AF was associated with lower volume of gray and white matter hyperintensities (P<0.001 and P = 0.008, respectively), but not of white matter hyperintensities (P = 0.49). Participants with AF scored lower on tests of memory.AF is associated with smaller brain volume, and the association is stronger with increasing burden of the arrhythmia. These findings suggest that AF has a cumulative negative effect on the brain independent of cerebral infarcts.Landspitali National University Hospital of Iceland Science Fund Helga Jonsdottir and Sigvaldi Kristjansson Memorial Fund National Institutes of Health/N01-AG-1-2100 National Institute on Aging Intramural Research Program Icelandic Heart Association Althingi (the Icelandic Parliament