There is evidence for different levels of visuospatial processing with their own frames of reference: viewer-centered, stimulus-centered, and object-centered. The neural locus of these levels can be explored by examining lesion location in subjects with unilateral spatial neglect (USN) manifest in these reference frames. Most studies regarding the neural locus of USN have treated it as a homogenous syndrome, resulting in conflicting results. In order to further explore the neural locus of visuospatial processes differentiated by frame of reference, we presented a battery of tests to 171 subjects within 48 hr after right supratentorial ischemic stroke before possible structural and/or functional reorganization. The battery included MR perfusion weighted imaging (which shows hypoperfused regions that may be dysfunctional), diffusion weighted imaging (which reveals areas of infarct or dense ischemia shortly after stroke onset), and tests designed to disambiguate between various types of neglect. Results were consistent with a dorsal/ventral stream distinction in egocentric/allocentric processing. We provide evidence that portions of the dorsal stream of visual processing, including the right supramarginal gyrus, are involved in spatial encoding in egocentric coordinates, whereas parts of the ventral stream (including the posterior inferior temporal gyrus) are involved in allocentric encoding.

Background: Semantic errors result from the disruption of access either to semantics or to lexical representations. One way to determine the origins of these errors is to evaluate comprehension of words that elicit semantic errors in naming. We hypothesized that in acute stroke there are different brain regions where dysfunction results in semantic errors in both naming and comprehension versus those with semantic errors in oral naming alone. Methods: A consecutive series of 196 patients with acute left hemispheric stroke who met inclusion criteria were evaluated with oral naming and spoken word/picture verification tasks and magnetic resonance imaging within 48 hours of stroke onset. We evaluated the relationship between tissue dysfunction in 10 pre-specified Brodmann's areas (BA) and the production of coordinate semantic errors resulting from (1) semantic deficits or (2) lexical access deficits. Results: Semantic errors arising from semantic deficits were most associated with tissue dysfunction/infarct of left BA 22. Semantic errors resulting from lexical access deficits were associated with hypoperfusion/infarct of left BA 37. Conclusion: Our study shows that semantic errors arising from damage to distinct cognitive processes reflect dysfunction of different brain regions.

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Introduction Unilateral neglect after acute right-hemispheric stroke significantly impedes post-stroke recovery. We studied patients with right-hemispheric stroke to determine if increasing age was associated with more frequent or more severe neglect. Methods 204 subjects with acute right-hemispheric stroke were administered eight neglect tests within five days of symptom onset (and within 24 hours of admission). Size of infarct was measured, and neglect tests were scored as percent error. “Any neglect” was defined as at least 10% error on any of a subset of the tests. Results When tested for neglect soon after acute stroke admission, 69.6% of subjects over 65 yo had “any neglect” (defined by comparison to a group of normal controls), compared with 49.4% of subjects 65 and younger (p=0.008). For every additional 10 years of age, patients were 1.83 times as likely to have neglect, even after adjusting for DWI infarct volume and NIHSS score (95% CI 1.38, 2.43). In addition, DWI volume and NIHSS independently predicted neglect. Score on virtually all of the neglect tests worsened as an effect of age. Percentage error on a line cancellation task was 3.8% higher for every additional 10 years of age, after adjustment for DWI volume and NIHSS (p=0.006). Similar results were found for other neglect tests. Conclusions Increasing age in patients with acute right-hemispheric stroke significantly increases the odds of unilateral neglect as well as severity of neglect, independently from size of the stroke or NIHSS score. Older patients have more brain atrophy and may be less able to compensate for cerebral infarction, or because they tend to have more cardioembolic strokes which may be more cortically based.

Diffusion-perfusion mismatch in left Brodmann area 37 was strongly associated with acute improvement in naming, independently of volume or percentage of total mismatch or diffusion or perfusion abnormality. These data indicate that mismatch in a particular area is a marker of salvageable tissue and an important predictor of potential for recovery of functions that depend on that area. Location of mismatch before treatment may help to predict potential benefits of reperfusion.

Emergency care systems (ECS) are undergoing a period of rapid development on the African continent. What were formerly large intake zones are now being shaped into dedicated emergency units. Emergency care providers are being trained via certificate and even residency programs. However, significant challenges still exist. Resource limitations, staffing, and other system inputs are often the easiest issues to identify, but they only account for part of the problem. There are other prominent barriers to the delivery of high quality emergency care including lack of governmental leadership, poor system and facility organization, lack of provider training, and community misunderstanding of ECS functions. Released in May 2019, World Health Assembly (WHA) 72 resolution 12.9 “Emergency care systems for universal health coverage: ensuring timely care for the acutely ill and injured” has squarely placed ECS strengthening as a priority item to member state governments. Moving forward, it will be important to ensure that these systems are set up for success, as high-quality emergency care systems have the potential to avert half of all deaths in low- and middle-income countries (LMIC). With momentum building from the recent WHA amendment and the health systems community more focused than ever on the consideration of quality in health systems design, it is of the utmost importance that ECS planners dovetail these interests such that these nascent systems are designed while 1) applying a systems thinking lens and 2) maintaining a focus on quality. This article helps to accomplish this by breaking down ECS into five major categories for evaluation as defined by the WHO Emergency Care Systems Assessment tool, providing an understanding of the functions of each, and identifying which indicators might be used to gauge performance. We also reinforce the notion that these indicators must dive deeper than system inputs and health outcomes, they must be patient centered in order to truly be reflective of success.

New structural and functional imaging methods continue to be developed at a rapid pace. In the last 25 years, advanced imaging techniques have provided insights into how language is represented and processed in the brain and how it can be disrupted by damage to, or dysfunction of, various parts of the brain. Imaging studies have also yielded new information regarding how individuals recover language after stroke. We briefly review the strengths and weaknesses of the various radiological methods currently used to study language and aphasia.

BackgroundEfforts to develop effective and regionally-appropriate emergency care systems in sub-Saharan Africa are hindered by a lack of data on both the burden of disease in the region and on the state of existing care delivery mechanisms. This study describes the burden of acute disease presenting to an emergency unit in Mahajanga, Madagascar.Methods and FindingsHandwritten patient registries on all emergency department patients presenting between 1 January 2011 and 30 September 2012 were reviewed and data entered into a database. Data included age, sex, diagnosis, and disposition. We classified diagnoses into Clinical Classifications Software (CCS) multi-level categories. The population was 53.5% male, with a median age of 31 years. The five most common presenting conditions were 1) Superficial injury; contusion, 2) Open wounds of head; neck; and trunk, 3) Open wounds of extremities, 4) Intracranial injury, and 5) Unspecified injury and poisoning. Trauma accounted for 48%, Infectious Disease for 15%, Mental Health 6.1%, Noncommunicable 29%, and Neoplasms 1.2%. The acuity seen was high, with an admission rate of 43%. Trauma was the most common reason for admission, representing 19% of admitted patients.ConclusionsThis study describes the burden of acute disease at a large referral center in northern Madagascar. The Centre Hôpitalier Universitaire de Mahajanga sees a high volume of acutely ill and injured patients. Similar to other reports from the region, trauma is the most common pathology observed, though infectious disease was responsible for the majority of adult mortality. Typhoid fever other intestinal infections were the most lethal CCS-coded pathologies. By utilizing a widely understood classification system, we are able to highlight contrasts between Mahajanga’s acute and overall disease burden as well as make comparisons between this region and the rest of the globe. We hope this study will serve to guide the development of context-appropriate emergency medicine systems in the region.