The Meta VCI Map consortium for meta-analyses on strategic lesion locations for vascular cognitive impairment using lesion-symptom mapping: design and multicenter pilot study

Introduction: The Meta VCI Map consortium performs meta-analyses on strategic lesion locations for vascular cognitive impairment using lesion-symptom mapping. Integration of data from different cohorts will increase sample sizes, to improve brain lesion coverage and support comprehensive lesion-symptom mapping studies. Methods: Cohorts with available imaging on white matter hyperintensities or infarcts and cognitive testing were invited. We performed a pilot study to test the feasibility of multicenter data processing and analysis and determine the benefits to lesion coverage. Results: Forty-seven groups have joined Meta VCI Map (stroke n = 7800 patients; memory clinic n = 4900; population-based n = 14,400). The pilot study (six ischemic stroke cohorts, n = 878) demonstrated feasibility of multicenter data integration (computed tomography/magnetic resonance imaging) and achieved marked improvement of lesion coverage. Discussion: Meta VCI Map will provide new insights into the relevance of vascular lesion location for cognitive dysfunction. After the successful pilot study, further projects are being prepared. Other investigators are welcome to join

Neuropsychology of colour vision: Studies in patients with acquired brain damage, healthy participants, and cases

In this thesis, we studied the neuropsychology of low-level sensory and higher-order visual perception in healthy participants, patients with acquired deficits in visual perception, and a man with a selective developmental deficit in colour processing. In neuropsychological literature, sensory disorders as well as higher-order recognition deficits have been reported after acquired brain damage. There is still considerable debate about the link between sensory disorders and higher-order, recognition deficits (i.e. agnosias). In this thesis, a relatively small group study is reported that investigated this link (Part I; Chapter 2). In the remainder of the thesis, colour vision is emphasised. In Part II, learned associations between colours and objects in healthy participants are dealt with (Chapters 3-5). Besides acquired impairments in visual perception, cases have been described with developmental deficits. The neuropsychology of colour vision, ranging from colour perception, discrimination, and categorisation to colour naming, object-colour knowledge and colour imagery, is extensively studied in a unique case of developmental colour agnosia (MAH) (Part III; Chapters 6-10). In this final chapter, a concise summary of the results from is presented along with the major conclusions and a discussion of methodological strengths and weaknesses of the experiments

Attended but unseen: Visual attention is not sufficient for visual awareness

Does any one psychological process give rise to visual awareness? One candidate is selective attention—when we attend to something it seems we always see it. But if attention can selectively enhance our response to an unseen stimulus then attention cannot be a sufficient precondition for awareness. Kentridge, Heywood & Weiskrantz [Kentridge, R. W., Heywood, C. A., & Weiskrantz, L. (1999). Attention without awareness in blindsight. Proceedings of the Royal Society of London, Series B, 266, 1805–1811; Kentridge, R. W., Heywood, C. A., & Weiskrantz, L. (2004). Spatial attention speeds discrimination without awareness in blindsight. Neuropsychologia, 42, 831–835.] demonstrated just such a dissociation in the blindsight subject GY. Here, we test whether the dissociation generalizes to the normal population. We presented observers with pairs of coloured discs, each masked by the subsequent presentation of a coloured annulus. The discs acted as primes, speeding discrimination of the colour of the annulus when they matched in colour and slowing it when they differed. We show that the location of attention modulated the size of this priming effect. However, the primes were rendered invisible by metacontrast-masking and remained unseen despite being attended. Visual attention could therefore facilitate processing of an invisible target and cannot, therefore, be a sufficient precondition for visual awareness

Introduction to the research topic novel insights in rehabilitation of neglect

Hemispatial neglect is the failure to report, respond to, or orient to novel or meaningful stimuli presented in the contralesional visual field. This failure cannot be attributed to motor or sensory defects (Heilman and Valenstein, 1979). It constitutes one of the most invalidating neurological disorders that can occur after stroke. As discussed in this Research Topic, patients with neglect are less independent in various activities of daily living compared to patients without neglect (Nijboer et al., 2013). It is therefore important to treat neglect as adequately as possible and much of the research dedicated to neglect therefore focuses on rehabilitation. Here we provide a brief overview of the 29 articles featured in this Research Topic

Spatial attention and eye movements

The space around us is highly crowded: even when performing a simple task like making a cup of coffee, there are generally a huge number of distracting elements in our environment that could interfere with the performance of this particular task. Although very few people will be able to arrange their kitchen such that there are no distracting elements, even the most tidy people with clean kitchens will face a challenging task: making coffee involves multiple elements that are relevant during different moments in the process. To keep performance on track, information relevant to the current goal and intention needs to be selected, while irrelevant information needs to be filtered out. This selection of a spatial element in the face of competition for selection by other elements has been termed “spatial attention.” As we will outline in this chapter, spatial attention is a multifaceted concept which involves various different components and functions. Although spatial attention is perhaps one of the most ill-defined terms in experimental psychology, the aim of the current chapter is to provide some understanding about what spatial attention entails and how deficits in spatial attention can tell us something about its underlying mechanisms. The description of the consequences of deficits in spatial attention will illustrate how crucial spatial attention is for our daily functioning

Impact of visuospatial neglect post-stroke on daily activities, participation and informal caregiver burden: a systematic review

Objectives: Visuospatial neglect (VSN) is a common cognitive disorder after stroke. The primary aim of this systematic review was to provide an overview of the impact of VSN in 3 aspects: (1) activities of daily living (ADL), (2) participation, and (3) caregiver burden. The second aim was to investigate the differences in studies focusing on populations with mean age = 65 years.Methods: PubMed, EMBASE, Web of Science, Cochrane Library, Emcare, PsychINFO, Academic Search Premier and CENTRAL were searched systematically. Quality was assessed with the Mixed Methods Appraisal Tool.Results: Of the 115 included studies, 104 provided outcomes on ADL, 15 on participation (4 studies with mean age >= 65), and 2 on caregiver burden (1 study with mean age >= 65). Quality assessment yielded scores ranging from 0 to 100%. VSN had a negative impact on ADL (i.e., independence during ADL and performance in self-care, household tasks, reading, writing, walking, wheelchair navigation) and participation (i.e., driving, community mobility, orientation, work). The impact of VSN on fulfilling social roles was unclear. VSN had a negative effect on caregiver burden. We found no clear age-related differences.Conclusions and implications: VSN has a negative impact not only on patients' independence but particularly on the performance of ADL. Despite the far fewer studies of VSN as compared with ADL, VSN also seems to hamper participation and increase caregiver burden, but further research is needed. Because of the large impact, VSN should be systematically and carefully assessed during rehabilitation. A considerable number of different instruments were used to diagnose VSN. Diagnosing VSN at more than one level [function (i.e., pen-and-paper test), activities, and participation] is strongly recommended. Consensus is needed on how to assess VSN and its negative impact for research and rehabilitation practice. (C) 2019 Elsevier Masson SAS. All rights reserved