Investigation of Visual Perceptions in Parkinson\u27s Disease and the Development of Disease Monitoring Software

Non-motor Parkinson’s Disease (PD) symptoms are substantial factors of PD arising throughout disease stages, yet their diagnosis and monitoring remain a challenge. Sensory abnormalities in PD occur across sensory systems and disease stages, contributing to disease-related impairments. However, the extent of symptoms is unknown, with inadequate monitoring and treatment options furthering disease management difficulties. The current work studies movement-independent visual perceptions of time, displacement and velocity in PD patients across disease stages using levodopa, deep brain stimulation (DBS), or no PD therapy. Perceptual tasks were conducted using a computer-generated graphical device designed with a focus on simplicity and flexibility. Perception of all tested visual modalities was impaired in PD (often extending to early PD stages), with negligible levodopa and DBS induced improvement. The observations help explain visuospatial, visual recognition and timing deficits occurring in PD while providing potential disease markers, and validates the graphical tool’s usefulness for disease diagnosis and monitoring

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

06. 2005 Seventeenth Annual IMSA Presentation Day

https://digitalcommons.imsa.edu/class_of_2005/1004/thumbnail.jp

2005 Seventeenth Annual IMSA Presentation Day

The Student Inquiry and Research Program fosters the development of students as highly skilled and integrative problem finders, problem solvers, and apprentice investigators, all skills required to succeed in the global workplace of the 21 Century.https://digitalcommons.imsa.edu/archives_sir/1017/thumbnail.jp

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy

Investigating Immersive Augmented Reality as a Rehabilitation Tool for Parkinson disease

Physical rehabilitation programs are often prescribed in an effort to maintain range of motion, and to adapt strategies for managing the debilitating symptoms of Parkinson disease (PD) in everyday life. An emerging trend to overcome the limitations of traditional rehabilitation is the use of virtual reality technologies. IThe goal of the present study was to determine the feasibility of augmented reality technology (IAR) in a rehabilitative setting. Three IAR environments were designed and a corresponding task was completed in each one. Not surprisingly, the control group generally performed better than the PD group on the tasks. All participants typically performed better in the real-world than the IAR environment. Additionally both the PD and control groups’ performances improved with repeated visits. The system was well-tolerated and important lessons are highlighted about future implementation of this rehabilitation approach (e.g., the need for a familiarization period to the system)

Industry/University Collaboration at the University of Michigan-Dearborn: A Focus on Relevant Technology

https://deepblue.lib.umich.edu/bitstream/2027.42/154105/1/kampfner1997.pd

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy. This edition celebrates twenty years of uninterrupted and succesfully research in the field of voice analysis

Visual processing mechanisms within magno, konio and parvocellular systems : implications for basic and clinical sciences

Tese de doutoramento em Ciências Biomédicas, apresentada à Faculdade de Medicina da Universidade de CoimbraPretendemos compreender novos aspectos da biofísica das vias de processamento da informação visual no Homem, na saúde e na doença. Introduzimos uma abordagem inovadora de biologia quantitativa baseada no desenvolvimento de métodos biofísicos de estudo da função neurosensorial que permitem isolar o funcionamento de vias paralelas de processamento de forma psicofísica. A questão de fundo é compreender de que forma os sensores biológicos codificam a informação relativa aos contrastes cromático/acromático em diferentes níveis do sistema visual humano, e como essa informação se mantém segregada em diferentes vias na retina e no córtex. Este trabalho inseriu-se assim num projecto de desenvolvimento de novos métodos de biofísica neurosensorial, em particular a sensibilidade ao contraste em vários canais de processamento, com aplicação às ciências da visão básicas e clínicas. Para tal desenvolveu-se uma metodologia psicofísica de análise do processamento da informação visual nos sistemas magno/conio/parvocelulares numa população de controlos e em indivíduos com a doença de Parkinson (DP). A quantificação biofísica dos défices das funções das vias conio/parvocelular realizou-se através da manipulação dos espaços de cor, de forma a medir limiares de discriminação cromática, permitindo medir independentemente a função dos cones (L, M e S). A função parvocelular foi ainda avaliada através de técnica perimétrica de sensibilidade ao contraste acromática. A função magnocelular foi isolada com a perimetria baseada em estímulos com duplicação ilusória de frequência (frequency doubling, FD) e através de uma bateria de testes de percepção visual de movimento (local e global). Este projecto de natureza interdisciplinar, que combina conceitos e ferramentas da física e da biologia, procurou ajudar a preencher uma lacuna ainda frequente na neurobiologia de sistemas, no que diz respeito à respeita a abordagem quantitativa da função do sistema visual na saúde e na doença. As novas metodologias estabelecidas, permitem o desenvolvimento de modelos funcionais de processamento da informação biológica, e sobretudo levam à reconsideração das relações genótipo-fenótipo e estrutura-função, que são de enorme relevância nas ciências da visão. Indivíduos de uma população normal de vários grupos etários foram estudados para a criação de uma base de dados normativa para cada método e foram adicionalmente validados em estudos isolados (em modelos clínicos de lesão das células ganglionares da retina, tais como, glaucoma e hipertensão ocular ou ainda num modelo genético do neurodesenvolvimento, o Síndrome de Williams). As assimetrias da função visuoespacial têm sido documentadas em termos electrofisiológicos e anatómicos, mas as suas consequências no desempenho visual encontram-se ainda pouco exploradas. Procurámos assim estudar estas assimetrias numa população normal através das técnicas psicofísicas de medição da sensibilidade ao contraste acromático que isolam as vias magno/parvocelulares. Foi comparada a performance entre os diversos quadrantes e hemicampos visuais. Este trabalho revelou pela primeira vez a presença de dois tipos de assimetria funcional nas vias visuais magno/parvocelulares, a primeira de origem provável na retina, e a segunda reflectindo também uma assimetria cortical inter-hemisférica. Neste estudo, centrámo-nos também na análise de assimetrias objectivas funcionais e estruturais ao nível da retina, e analisámos a sua correlação com as assimetrias no desempenho visual. Concluímos que os padrões de assimetria estrutural/funcional surgem a diferentes níveis da retina, conforme sugerido pelo padrão de correlação parcial observado. O presente trabalho teve também por objectivo aprofundar a avaliação de funções visuais em sujeitos com a DP, utilizando para tal testes psicofísicos mais precisos e sensíveis que os métodos anteriormente empregues. Estudámos de forma independente as vias magno/parvo/coniocelulares e encontrámos envolvimento significativo de todas estas vias neuronais nesta doença. Os resultados deste trabalho vêm revelar que a avaliação da via parvocelular (cones L e M) parece ser pelo menos tão promissora como a estratégia tradicional de estudo da via coniocelular (cones S). Verificou-se existir uma correlação da performance com a idade e com o estadio da doença, apenas para a via magnocelular. O estudo da percepção visual do movimento na DP permitiu comparar a disfunção em vias visuais de baixo nível (retinocortical magnocelular), de nível intermédio e superior (via dorsal), e análise das suas interdependências. Esta estratégia inovadora de análise a vários níveis hierárquicos do sistema visual permitiu demonstrar pela primeira vez, a dissociação entre baixo e alto nível de processamento visual na DP. Verificou-se alteração na percepção do movimento (de origem cortical), e curiosamente, os danos da via periférica magnocelular não se correlacionaram com a percepção de alto nível de movimento, sugerindo assim que a deficiência visual de baixo nível não prevê comprometimento da via dorsal. O que implica que, tais perturbações não podem ser explicadas totalmente por défices precoces na retina bem como ao nível da via precoce retinocortical magnocelular. Este trabalho permitiu assim estudar, de forma independente, as funções visuais de baixo e alto nível na saúde e na doença.We want to understand the biophysical aspects of parallel processing of visual information in humans, in health and disease. We introduced a novel approach to quantitative biology based on the development of new biophysical methods by isolating visual parallel processing in terms of psychophysics. The main question is to understand how the biological sensors encode the information on achromatic/chromatic contrast at different levels of the human visual system, and how that information is kept segregated in different pathways from the retina to the cortex. For this purpose, new methods were developed, in particular, contrast sensitivity multi-channel processing tasks, with application to basic science and clinical vision. The biophysical quantification of deficits in conio/parvocellular processing was held by manipulating the colour spaces in order to measure chromatic discrimination thresholds, allowing independent functional measures of the cones (L, M and S). Parvocellular function was further assessed by a custom perimetry technique of achromatic contrast sensitivity. The magnocellular function was isolated by custom perimetry based on frequency doubling (FD) stimuli and through a battery of visual motion perception tests (local and global motion tasks). This project of interdisciplinary nature, combining concepts and tools of physics and biology, has helped to fill a gap still widespread in neurobiology of systems, in terms, of a quantitative approach of visual function in health and disease. The new methodologies established allowed the development of functional processing models of biological information, and especially lead to the reconsideration of genotype-phenotype and structure-function relationships, which are of major importance in vision science. Individuals of a normal population of various age groups were studied to establish normative databases for each method and were further validated in isolated models (such as clinical models of injury to retinal ganglion cells, as in glaucoma and ocular hypertension or in genetic models of neurodevelopment, the Williams Syndrome). Asymmetries of spatial vision processing have been documented in electrophysiological and anatomical terms, but their impact on visual performance are still poorly explored. We tried to study these asymmetries in a normal population through psychophysical measurements of achromatic contrast sensitivity by isolating magno/parvocellular pathways. We compared the functional visual performance between different visual field quadrants and hemifields. This study showed for the first time the presence of two types of functional asymmetry in magno/parvocellular pathways, the first one with a likely source on the retina, and the second reflecting also a cortical interhemispheric asymmetry. This suggests that both cortical and retinal visual maps are functionally heterogeneous. We also focused on the analysis of structural and objective functional asymmetries at the level of the retina, and examined its correlation with asymmetries in terms of visual performance. We concluded that structural/functional patterns of asymmetry arise at different levels of the retina, as suggested by the observed pattern of partial correlation. The present work also aimed to evaluate the visual function in subjects with PD, using more accurate and sensitive psychophysical tests than previous methods. We studied independently the magno/parvo/coniocellular pathways and found meaningful involvement of all of these neuronal pathways in PD disease. We found that the parvocellular (M and L cones) assessment seems to be at least as promising as the traditional approach of studying coniocellular stream (S cones). A correlation between visual performance with age and disease stage was found only for the magnocellular pathway. The study of visual motion perception in PD involved the use of a range of hierarchical stimuli designed to bias responses from low-level (magnocellular), intermediate-level and higher-level (dorsal stream) visual pathways and study their interdependence. The novelty of this strategy lies in the analysis of various hierarchical levels of the visual system, showing for the first time, the dissociation between low- and high-level visual processing in PD. Impairment of motion perception in the cortex was found in PD, and interestingly, there was no correlation between low-level damage and motion integration impairment. Thus, suggesting that the visually impaired magnocellular stream does not predict impairment of the dorsal pathway, implying that such disturbances can not be explained entirely by early deficits in the retina as well as in the early magnocellular pathway (retina to sub-cortical, striate and extra-striate regions). This study allowed to probe independently low- and high-level visual function in health and disease