3,492 research outputs found

    Skert innsæi (anosognosia) í Alzheimerssjúkdómi

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    Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenEinstaklinga, sem hafa orðið fyrir heilaskaða, virðist stundum skorta innsæi í líkamlegt og vitrænt ástand sitt. Sjúklingar sem hafa lamast sökum heilablóðfalls (hemiplegic) gera sér stundum ekki grein fyrir hreyfihömluninni, sumir með málstol taka ekki eftir breytingum á tali og minnissjúkir einstaklingar taka stundum ekki eftir minniserfiðleikum (McGlynn & Schacter, 1987). Þetta skerta innsæi sem oft fylgir heilaskaða hefur lengi verið þekkt fyrirbæri en Babinski (1914) var fyrstur til að gefa fyrirbærinu heitið: anosognosia

    Saturated gain spectrum of VECSELs determined by transient measurement of lasing onset

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    We describe time-resolved measurements of the evolution of the spectrum of radiation emitted by an optically-pumped continuous-wave InGaAs-GaAs quantum well laser, recorded as lasing builds up from noise to steady state. We extract a fitting parameter corresponding to the gain dispersion of the parabolic spectrum equal to ?79 ± 30 fs2 and ?36 ± 6 fs2 for a resonant and anti-resonant structure, respectively. Furthermore the recorded evolution of the spectrum allows for the calculation of an effective FWHM gain bandwidth for each structure, of 11 nm and 18 nm, respectively

    The Brief Memory and Executive Test (BMET) for detecting vascular cognitive impairment in small vessel disease: a validation study

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    Background: Cognitive impairment is common in patients with cerebral small vessel disease, but is not well detected using common cognitive screening tests which have been primarily devised for cortical dementias. We developed the Brief Memory and Executive Test (BMET); a rapid screening measure sensitive to the impaired executive function and processing speed characteristic of small vessel disease (SVD). To assess the BMET’s validity for general use, we evaluated it when administered by non-psychologists in a multicentre study and collected control data to derive normative scores. Methods: Two-hundred participants with SVD, defined as a clinical lacunar stroke and a corresponding lacunar infarct on MRI, and 303 healthy controls aged between 40–90 years old were recruited. The BMET, as well as the Montreal Cognitive Assessment (MoCA) and Mini Mental State Examination (MMSE), were performed. Overall, 55 SVD participants underwent repeat testing at 3 months to assess the BMET test-retest reliability. Results: Administering the BMET took a mean (SD) of 12.9 (4.7) in cases and 9.5 (2.6) minutes in controls. Receiver Operator Curve analysis showed the BMET was a good predictor of cognitive impairment in SVD (AUC = 0.94) and performed significantly better than both the MoCA (AUC = 0.77) and the MMSE (AUC = 0.70). Using a cut-off score of 13, the BMET had a sensitivity of 93% and specificity of 76% for detecting cognitive impairment in SVD. Conclusions: The BMET is a brief and sensitive tool for the detection of cognitive impairment in patients with SVD.The BMET study was funded by The Stroke Association (TSA2010/08). Recruitment to BMET was supported by the NIHR Stroke Clinical Research Network. Hugh Markus is supported by an NIHR Senior Investigator award and his work is supported by the Cambridge University Hospitals NIHR Comprehensive BRC. Matthew Hollocks is supported by a Stroke Association/British Heart Foundation Grant (TSA BHF 2010/01). Robin Morris receives consultancy fees for P1Vital Limited. The authors disclose no competing interests financial or otherwise.This is the final published version. It first appeared at http://www.biomedcentral.com/content/pdf/s12916-015-0290-y.pdf

    Apathy, but not depression, is associated with executive dysfunction in cerebral small vessel disease.

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    OBJECTIVE: To determine the prevalence of apathy and depression in cerebral small vessel disease (SVD), and the relationships between both apathy and depression with cognition. To examine whether apathy is specifically related to impairment in executive functioning and processing speed. METHODS: 196 patients with a clinical lacunar stroke and an anatomically corresponding lacunar infarct on MRI were compared to 300 stroke-free controls. Apathy and depression were measured using the Geriatric Depression Scale, and cognitive functioning was assessed using an SVD cognitive screening tool, the Brief Memory and Executive Test, which measures executive functioning/processing speed and memory/orientation. Path analysis and binary logistic regression were used to assess the relation between apathy, depression and cognitive impairment. RESULTS: 31 participants with SVD (15.8%) met criteria for apathy only, 23 (11.8%) for both apathy and depression, and 2 (1.0%) for depression only. In the SVD group the presence of apathy was related to global cognition, and specifically to impaired executive functioning/processing speed, but not memory/orientation. The presence of depression was not related to global cognition, impaired executive functioning/processing speed or memory/orientation. CONCLUSIONS: Apathy is a common feature of SVD and is associated with impaired executive functioning/processing speed suggesting the two may share biological mechanisms. Screening for apathy should be considered in SVD, and further work is required to develop and evaluate effective apathy treatment or management in SVD.This work was supported by a Priority Program Grant from the Stroke Association (TSA PPA 2015-02; www.stroke.org.uk). The BMET Study was supported by a grant from the Stroke Association (TSA2008/10). Valerie Lohner is supported by a Stroke Association/British Heart Foundation Program Grant (TSA BHF 2010/01; www.bhf.org.uk). Rebecca Brookes is supported by a BHF Project Grant (PG/13/30/30005). Recruitment to the BMET Study was supported by the English National Institute of Health Research (NIHR) Clinical Stroke Research Network (www.crn.nihr.ac.uk/stroke). Hugh Markus is supported by an NIHR Senior Investigator award (www.nihr.ac.uk) and his work is supported by the Cambridge University Hospital Comprehensive NIHR Biomedical Research Unit (www.cambridge-brc.org.uk)

    Brief Screening of Vascular Cognitive Impairment in Patients With Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Without Dementia.

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    BACKGROUND AND PURPOSE: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic form of cerebral small vessel disease leading to early-onset stroke and dementia, with younger patients frequently showing subclinical deficits in cognition. At present, there are no targeted cognitive screening measures for this population. However, the Brief Memory and Executive Test (BMET) and the Montreal Cognitive Assessment (MoCA) have shown utility in detecting cognitive impairment in sporadic small vessel disease. This study assesses the BMET and the MoCA as clinical tools for detecting mild cognitive deficits in CADASIL. METHODS: Sixty-six prospectively recruited patients with CADASIL, and 66 matched controls completed the BMET, with a subset of these also completing the MoCA. Receiver operating characteristic curves were calculated to examine the sensitivity and specificity of clinical cutoffs for the detection of vascular cognitive impairment and reduced activities of daily living. RESULTS: Patients with CADASIL showed more cognitive impairment overall and were poorer on both executive/processing and memory indices of the BMET relative to controls. The BMET showed good accuracy in predicting vascular cognitive impairment (85% sensitivity and 84% specificity) and impaired instrumental activities of daily living (92% sensitivity and 77% specificity). The MoCA also showed good predictive validity for vascular cognitive impairment (80% sensitivity and 78% specificity) and instrumental activities of daily living (75% sensitivity and 76% specificity). The most important background predictor of vascular cognitive impairment was a history of stroke. CONCLUSIONS: The results indicate that the BMET and the MoCA are clinically useful and sensitive screening measures for early cognitive impairment in patients with CADASIL.Stroke Association (Grant ID: TSA2008/10), British Heart Foundation (Grant ID: PG/13/30/30005), Stroke Association/British Heart Foundation (Grant ID: TSA BHF 2010/01), Agency for Science, Technology and Research, Singapore, National Institute for Health Research (Senior Investigator award), Cambridge University Hospital Comprehensive National Institute for Health Research Biomedical Research UnitThis is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1161/STROKEAHA.116.01376

    Apathy after stroke: Diagnosis, mechanisms, consequences, and treatment

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    Apathy is a reduction in goal-directed activity in the cognitive, behavioral, emotional, or social domains of a patient’s life and occurs in one out of three patients after stroke. Despite this, apathy is clinically under-recognized and poorly understood. This overview provides a contemporary introduction to apathy in stroke for researchers and practitioners, covering topics including diagnosis, neurobiological mechanisms, associated consequences, and potential treatments for apathy. Apathy is often misdiagnosed as other post-stroke conditions such as depression. Accurate differential diagnosis of apathy, which manifests as reductions in initiative, and depression, which manifests as negative emotionality, is important as it informs prognosis. Research on the neurobiology of apathy suggests that there are few consistent associations between stroke lesion location and the development of apathy. These may be resolved by adopting a network neuroscience approach, which models apathy as a pathology arising from structural or functional damage to brain networks underlying motivated behavior. Importantly, networks can be affected by physiological changes related to stroke, including the acute infarct but also diaschisis and neurodegeneration. Aside from neurobiological changes, apathy is also associated with other negative outcome measures such as functional disability, cognitive impairment, and emotional distress, suggesting that apathy is indicative of a worse prognosis following stroke. Unfortunately, high-quality trials aimed at treating apathy are scarce. Antidepressants may have limited effects on apathy. Acetylcholine and dopamine pharmacotherapy, behavioral interventions, and transcranial magnetic stimulation may be more promising avenues for treatment

    Pattern and Rate of Cognitive Decline in Cerebral Small Vessel Disease: A Prospective Study.

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    OBJECTIVES: Cognitive impairment, predominantly affecting processing speed and executive function, is an important consequence of cerebral small vessel disease (SVD). To date, few longitudinal studies of cognition in SVD have been conducted. We determined the pattern and rate of cognitive decline in SVD and used the results to determine sample size calculations for clinical trials of interventions reducing cognitive decline. METHODS: 121 patients with MRI confirmed lacunar stroke and leukoaraiosis were enrolled into the prospective St George's Cognition And Neuroimaging in Stroke (SCANS) study. Patients attended one baseline and three annual cognitive assessments providing 36 month follow-up data. Neuropsychological assessment comprised a battery of tests assessing working memory, long-term (episodic) memory, processing speed and executive function. We calculated annualized change in cognition for the 98 patients who completed at least two time-points. RESULTS: Task performance was heterogeneous, but significant cognitive decline was found for the executive function index (p<0.007). Working memory and processing speed decreased numerically, but not significantly. The executive function composite score would require the smallest samples sizes for a treatment trial with an aim of halting decline, but this would still require over 2,000 patients per arm to detect a 30% difference with power of 0.8 over a three year follow-up. CONCLUSIONS: The pattern of cognitive decline seen in SVD over three years is consistent with the pattern of impairments at baseline. Rates of decline were slow and sample sizes would need to be large for clinical trials aimed at halting decline beyond initial diagnosis using cognitive scores as an outcome measure. This emphasizes the importance of more sensitive surrogate markers in this disease.This work was supported by the Wellcome Trust [grant number 081589] and Alzheimer's Research UK [grant number ARUK-PG2013-2].This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pone.013552

    Apathy, but not depression, predicts all-cause dementia in cerebral small vessel disease

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    Objective: To determine whether apathy or depression predicts all-cause dementia in small vessel disease (SVD) patients. Methods: Analyses used two prospective cohort studies of SVD: St. George’s Cognition and Neuroimaging in Stroke (SCANS; n=121) and Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort (RUN DMC; n=352). Multivariate Cox regressions were used to predict dementia using baseline apathy and depression scores in both datasets. Change in apathy and depression was used to predict dementia in a subset of 104 participants with longitudinal data from SCANS. All models were controlled for age, education and cognitive function. Results: Baseline apathy scores predicted dementia in SCANS (HR 1.49, 95% CI 1.05 to 2.11, p=0.024) and RUN DMC (HR 1.05, 95% CI 1.01 to 1.09, p=0.007). Increasing apathy was associated with dementia in SCANS (HR 1.53, 95% CI 1.08 to 2.17, p=0.017). In contrast, baseline depression and change in depression did not predict dementia in either dataset. Including apathy in predictive models of dementia improved model fit. Conclusions: Apathy, but not depression, may be a prodromal symptom of dementia in SVD, and may be useful in identifying at-risk individuals
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