Made available in DSpace on 2015-07-22T20:50:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-24 / A Doença de Alzheimer é a causa mais frequente de demência. Os sintomas clínicos da doença se iniciam com um comprometimento da memória e da função executiva, gradativamente há um envolvimento de outras funções como a linguagem, conhecimento semântico, pensamento abstrato, atenção e habilidades visuoespaciais. A função visuoespacial consiste na identificação de um estímulo e sua localização, e pode estar comprometida no início do quadro clínico. A bateria “Visual Object and Space Perception” (VOSP) se propõe a avaliar as funções visuoespaciais minimizando a interferência de outras funções cognitivas. Objetivos: Avaliar as funções visuoespaciais na doença de Alzheimer de intensidade leve; Avaliar a sensibilidade desta bateria em uma amostra brasileira; Determinar escores de corte preliminares para diferenciar idosos saudáveis de pacientes com doença de Alzheimer. Métodos: 31 pacientes com Doença de Alzheimer leve e 44 idosos saudáveis foram avaliados com uma bateria de testes neuropsicológicos e com a VOSP. Resultados: Controles tiveram melhor desempenho em todos os testes neuropsicológicos. Na VOSP, os pacientes com Doença de Alzheimer mostraram pior desempenho em todos os testes de percepção de objeto, e em dois testes de percepção de espaço (Localização de Numero e Análise de Cubos). Conclusões: A função visuoespacial mostra-se comprometida em estágios iniciais da doença de Alzheimer. A bateria VOSP demonstrou ser sensível a déficits visuoespaciais. / TEDE / BV UNIFESP: Teses e dissertações

This mini-thesis is a supporting document to the exhibition titled via: a phenomenological site-specific series of intermedia interventions and installations at the 1820 Settlers National Monument in Grahamstown. This mini-thesis examines ways in which one negotiates the movement of the self and interactions with others within the non-place. Non-places are ‘habitually transient’ spaces for passage, communication and consumption, often viewed from highways, vehicles, hotels, petrol stations, airports and supermarkets. Characteristic of these generic and somewhat homogenous spaces is the paradox of material excess and concurrent psychological lack where a feeling of disorientation and disconnection is established due to the excesses of Supermodernity: excess of the individual, time and space. The non-place is a contested space as it does not hold enough significance to be regarded as a place and yet, despite its banality, is necessary – and in many ways a privilege – in everyday living. I explore the concept of non-places in relation to the intricate notions of space and place, and draw on empirical research as a means to interrogate how one perceives the phenomenological qualities of one’s surroundings. I discuss the implications of the multiplication of the non-place in relation to globalisation, time–space compression, site-specific art and absentmindedness, as theoretical themes which underpin the practical component of my research. In addition, I situate my artistic practice in relation to other contemporary artists dealing with the non-place as a theme, and critically engage with the multi-disciplinary and sensory installations and video pieces of Belgian artist Hans Op de Beeck.

La diffusion de données multimédia, et particulièrement les images, continuent à croitre de manière très significative. La recherche de schémas de codage efficaces des images reste donc un domaine de recherche très dynamique. Aujourd'hui, une des technologies innovantes les plus marquantes dans ce secteur est sans doute le passage à un affichage 3D. La technologie 3D est largement utilisée dans les domaines de divertissement, d'imagerie médicale, de l'éducation et même plus récemment dans les enquêtes criminelles. Il existe différentes manières de représenter l'information 3D. L'une des plus répandues consiste à associer à une image classique dite de texture, une image de profondeur de champs. Cette représentation conjointe permet ainsi une bonne reconstruction 3D dès lors que les deux images sont bien corrélées, et plus particulièrement sur les zones de contours de l'image de profondeur. En comparaison avec des images 2D classiques, la connaissance de la profondeur de champs pour les images 3D apporte donc une information sémantique importante quant à la composition de la scène. Dans cette thèse, nous proposons un schéma de codage scalable d'images 3D de type 2D + profondeur avec des fonctionnalités avancées, qui préserve toute la sémantique présente dans les images, tout en garantissant une efficacité de codage significative. La notion de préservation de la sémantique peut être traduite en termes de fonctionnalités telles que l'extraction automatique de zones d'intérêt, la capacité de coder plus finement des zones d'intérêt par rapport au fond, la recomposition de la scène et l'indexation. Ainsi, dans un premier temps, nous introduisons un schéma de codage scalable et joint texture/profondeur. La texture est codée conjointement avec la profondeur à basse résolution, et une méthode de compression de la profondeur adaptée aux caractéristiques des cartes de profondeur est proposée. Ensuite, nous présentons un schéma global de représentation fine et de codage basé contenu. Nous proposons ainsi schéma global de représentation et de codage de "Profondeur d'Intérêt", appelé "Autofocus 3D". Il consiste à extraire finement des objets en respectant les contours dans la carte de profondeur, et de se focaliser automatiquement sur une zone de profondeur pour une meilleure qualité de synthèse. Enfin, nous proposons un algorithme de segmentation en régions d'images 3D, fournissant une forte consistance entre la couleur, la profondeur et les régions de la scène. Basé sur une exploitation conjointe de l'information couleurs, et celle de profondeur, cet algorithme permet la segmentation de la scène avec un degré de granularité fonction de l'application visée. Basé sur cette représentation en régions, il est possible d'appliquer simplement le même principe d'Autofocus 3D précédent, pour une extraction et un codage de la profondeur d'Intérêt (DoI). L'élément le plus remarquable de ces deux approches est d'assurer une pleine cohérence spatiale entre texture, profondeur, et régions, se traduisant par une minimisation des problèmes de distorsions au niveau des contours et ainsi par une meilleure qualité dans les vues synthétisées. / Dissemination of multimedia data, in particular the images, continues to grow very significantly. Therefore, developing effective image coding schemes remains a very active research area. Today, one of the most innovative technologies in this area is the 3D technology. This 3D technology is widely used in many domains such as entertainment, medical imaging, education and very recently in criminal investigations. There are different ways of representing 3D information. One of the most common representations, is to associate a depth image to a classic colour image called texture. This joint representation allows a good 3D reconstruction, as the two images are well correlated, especially along the contours of the depth image. Therefore, in comparison with conventional 2D images, knowledge of the depth of field for 3D images provides an important semantic information about the composition of the scene. In this thesis, we propose a scalable 3D image coding scheme for 2D + depth representation with advanced functionalities, which preserves all the semantics present in the images, while maintaining a significant coding efficiency. The concept of preserving the semantics can be translated in terms of features such as an automatic extraction of regions of interest, the ability to encode the regions of interest with higher quality than the background, the post-production of the scene and the indexing. Thus, firstly we introduce a joint and scalable 2D plus depth coding scheme. First, texture is coded jointly with depth at low resolution, and a method of depth data compression well suited to the characteristics of the depth maps is proposed. This method exploits the strong correlation between the depth map and the texture to better encode the depth map. Then, a high resolution coding scheme is proposed in order to refine the texture quality. Next, we present a global fine representation and contentbased coding scheme. Therefore, we propose a representation and coding scheme based on "Depth of Interest", called "3D Autofocus". It consists in a fine extraction of objects, while preserving the contours in the depth map, and it allows to automatically focus on a particular depth zone, for a high rendering quality. Finally, we propose 3D image segmentation, providing a high consistency between colour, depth and regions of the scene. Based on a joint exploitation of the colour and depth information, this algorithm allows the segmentation of the scene with a level of granularity depending on the intended application. Based on such representation of the scene, it is possible to simply apply the same previous 3D Autofocus, for Depth of Interest extraction and coding. It is remarkable that both approaches ensure a high spatial coherence between texture, depth, and regions, allowing to minimize the distortions along object of interest's contours and then a higher quality in the synthesized views.

Performance on the Spatial Span subtest of the Wechsler Memory Scale has been viewed as an indicator of working memory and visuospatial processing. A number of factors including age and gender have been posited to effect performance on Spatial Span by older adults. The current study examined the impact of various forms of cognitive impairment and severity of impairment on Spatial Span performance. Five hundred thirty-eight individuals between the ages of 65 and 89 were evaluated in a university memory disorders clinic using a battery of neuropsychological tests that included Spatial Span. Participants were grouped by consensus diagnosis into type of cognitive impairment (Alzheimer's disease, vascular disease, amnestic mild cognitive impairment or non-amnestic mild cognitive impairment) or cognitively normal. As expected, an increase in severity of impairment results in a decrease in Spatial Span Total Score. Other findings included a weak relationship between age and Spatial Span Total Score. Gender, as well as age, did not fully account for the decline in Spatial Span Total Score. Spatial Span Forward score was not as good a predictor of severity in that reduction in score for Spatial Span Forward remains relatively stable regardless of level of impairment. Spatial Span Backward performance was found to be more sensitive to severity. No significant differences were found between performance of Alzheimer's disease and vascular disease suggesting they share similar deficit patterns with regard to the cognitive abilities measured by the Spatial Span subtest. A comparison between those diagnosed with mild cognitive impairment and individuals without such a diagnosis showed no significant difference suggesting that visuospatial processes are not affected early in the dementing process.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Image is a dominant medium among video, 3D model, and other media for visualizing environment and creating virtual access on the Internet. The location of image capture is, however, subjective and has relied on the esthetic sense of photographers up until this point. In this paper, we will not only visualize areas with images, but also propose a general framework to determine where the most distinct viewpoints should be located. Starting from elevation data, we present spatial and content information in ground-based images such that (1) a given number of images can have maximum coverage on informative scenes; (2) a set of key views can be selected with certain continuity for representing the most distinct views. According to the scene visibility, continuity, and data redundancy, we evaluate viewpoints numerically with an object-emitting illumination model. Our key view exploration may eventually reduce the visual data to transmit, facilitate image acquisition, indexing and interaction, and enhance perception of spaces. Real sample images are captured based on planned positions to form a visual network to index the area.

No / Language is more than a source of information for accessing higher-order conceptual knowledge. Indeed, language may determine how people perceive and interpret visual stimuli. Visual processing in linguistic contexts, for instance, mirrors language processing and happens incrementally, rather than through variously-oriented fixations over a particular scene. The consequences of this atypical visual processing are yet to be determined. Here, we investigated the integration of visual and linguistic input during a reasoning task. Participants listened to sentences containing conjunctions or disjunctions (Nancy examined an ant and/or a cloud) and looked at visual scenes containing two pictures that either matched or mismatched the nouns. Degree of match between nouns and pictures (referential anchoring) and between their expected and actual spatial positions (spatial anchoring) affected fixations as well as judgments. We conclude that language induces incremental processing of visual scenes, which in turn becomes susceptible to reasoning errors during the language-meaning verification process.

No / BACKGROUND: Tripping is a common factor in falls and a typical safety strategy to avoid tripping on steps or stairs is to increase foot clearance over the step edge. In the present study we asked whether the perceived height of a step could be increased using a visual illusion and whether this would lead to the adoption of a safer stepping strategy, in terms of greater foot clearance over the step edge. The study also addressed the controversial question of whether motor actions are dissociated from visual perception. METHODOLOGY/PRINCIPAL FINDINGS: 21 young, healthy subjects perceived the step to be higher in a configuration of the horizontal-vertical illusion compared to a reverse configuration (p = 0.01). During a simple stepping task, maximum toe elevation changed by an amount corresponding to the size of the visual illusion (p<0.001). Linear regression analyses showed highly significant associations between perceived step height and maximum toe elevation for all conditions. CONCLUSIONS/SIGNIFICANCE: The perceived height of a step can be manipulated using a simple visual illusion, leading to the adoption of a safer stepping strategy in terms of greater foot clearance over a step edge. In addition, the strong link found between perception of a visual illusion and visuomotor action provides additional support to the view that the original, controversial proposal by Goodale and Milner (1992) of two separate and distinct visual streams for perception and visuomotor action should be re-evaluated.

No description available.

The purpose of this study was to confirm the original factor structure of the Wide Range Assessment of Memory and Learning (WRAML) utilizing a non-clinical adolescent population. Additional analysis examined the relationship between SAT-M scores and spatial relations ability. Exploratory analyses were conducted to determine ethnic and gender differences on the WRAML and subtests from the DAT. Sixty-four academically talented adolescents completed the WRAML and the mechanical reasoning and spatial relations subtests from the Differential Aptitude Test (DAT). The confirmatory factor analysis found the data obtained to not be a good fit for the factor structure of the WRAML (Sheslow & Adams, 1990). Additional confirmatory analyses were conducted which examined data fit of a three factor model found by reanalyzing the standardization data (Burton et al., 1996; Wasserman & Cambias, 1991) as well as two null models. The data failed to fit any of these three models. No support was found for the second hypothesis that predicted a positive relationship between SAT-M scores and spatial relations ability. Ethnic and gender differences on the WRAML and two DAT subtests were examined and discussed. Limitations of this study were reviewed which may have accounted for the overall lack of results.