Advisor(s)
Abstract(s)
A Ressonância Magnética funcional (fMRI) é hoje uma ferramenta fundamental na investigação funcional do cérebro humano quer em indivíduos saudáveis quer em doentes com as mais diversas patologias. É um método de diagnóstico complexo que necessita de uma aplicação cuidada e rigorosa e uma compreensão dos mecanismos biofísicos a ele subjacentes, de modo a serem obtidos resultados fiáveis e com melhor aceitação clínica. O efeito dependente do nível de oxigenação do sangue (BOLD) é o método mais utilizado para medir e estudar a actividade cerebral e baseia-se nas alterações das propriedades magnéticas da molécula de hemoglobina do sangue. Esta investigação tem por objectivo principal verificar as diferentes respostas cerebrais, nas áreas da visão, audição e motora, em atletas de judo deficientes visuais e a sua comparação com judocas normovisuais As imagens foram adquiridas com recurso fMRI, realizada com o efeito BOLD, com diferentes paradigmas: sonoro, motor e sensório-motor. Foram estudados 12 atletas de judo, 6 com deficiência visual e 6 normovisuais. As imagens foram processadas com o auxílio do software FSL e mais propriamente com as seguintes ferramentas: MELODIC e FEAT (http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/). Foi observada a activação do córtex visual em ambos os grupos de voluntários (atletas de judo deficientes visuais e normovisuais) quando receberam um estímulo verbal associado a uma acção motora. O que leva a concluir que a perda de visão não leva à permanente inactivação do córtex visual. A cegueira leva, assim, à adaptação do córtex visual para a análise de informações de outros órgãos dos sentidos, em particular auditivas e tácteis (plasticidade cerebral).
Esta investigação contribui, assim, para: o conhecimento e desenvolvimento de estudos na área da ressonância magnética funcional vocacionados para o apoio à prática desportiva de atletas com deficiência visual; orientar os clínicos nas decisões terapêuticas em casos de doenças indutivas de deficiência visual e; melhorar as metodologias de treino e a eficiência na comunicação entre os treinadores e os atletas com este handicap.
ABSTRACT - Functional Magnetic Resonance Imaging (fMRI) is today an essential tool in human brain functional research, allowing us to study the brain of healthy individuals and patients. It is a complex technique that requires a careful and rigorous application and a knowledge of the biophysical mechanisms related to it, so that more reliable results are obtained as well as clinical acceptance. The Blood Oxygen Level Dependent (BOLD) is the most used method to measure and to study brain activity via MRI and is based on changes in the magnetic properties of the hemoglobin molecule. The main aim of this project is to verify the different brain responses in vision, hearing and motor areas in blind judo athletes and compare them with sighted judo athletes. Images were acquired using fMRI, performed with the BOLD effect, in different paradigms: motor execution, motor imagery and sensory touch. We studied 12 judo athletes, 6 visually impaired and 6 sighted. The images were processed with aid of the FSL software and more specifically with the following tools: MELODIC and FEAT (http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/). In both groups of volunteers (sighted and blind athletes) the visual cortex was observed when they received a verbal stimulus associated with a motor action. This takes to the conclusion that vision loss does not lead to permanent inactivation of the visual cortex. Blindness leads to an adaptation of the visual cortex for analyzing information from other sense organs, particularly auditory and tactile (brain plasticity). Thus, this research contributes to: understanding and development of studies in functional MRI geared to support the sport for athletes with a visual impairment; guide clinical treatment decisions in cases of inductive diseases and visual impairment, and; improve training methodologies and effective communication between coaches and athletes with this handicap.
ABSTRACT - Functional Magnetic Resonance Imaging (fMRI) is today an essential tool in human brain functional research, allowing us to study the brain of healthy individuals and patients. It is a complex technique that requires a careful and rigorous application and a knowledge of the biophysical mechanisms related to it, so that more reliable results are obtained as well as clinical acceptance. The Blood Oxygen Level Dependent (BOLD) is the most used method to measure and to study brain activity via MRI and is based on changes in the magnetic properties of the hemoglobin molecule. The main aim of this project is to verify the different brain responses in vision, hearing and motor areas in blind judo athletes and compare them with sighted judo athletes. Images were acquired using fMRI, performed with the BOLD effect, in different paradigms: motor execution, motor imagery and sensory touch. We studied 12 judo athletes, 6 visually impaired and 6 sighted. The images were processed with aid of the FSL software and more specifically with the following tools: MELODIC and FEAT (http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/). In both groups of volunteers (sighted and blind athletes) the visual cortex was observed when they received a verbal stimulus associated with a motor action. This takes to the conclusion that vision loss does not lead to permanent inactivation of the visual cortex. Blindness leads to an adaptation of the visual cortex for analyzing information from other sense organs, particularly auditory and tactile (brain plasticity). Thus, this research contributes to: understanding and development of studies in functional MRI geared to support the sport for athletes with a visual impairment; guide clinical treatment decisions in cases of inductive diseases and visual impairment, and; improve training methodologies and effective communication between coaches and athletes with this handicap.
Description
Mestrado em Radiações Aplicadas às Tecnologias da Saúde - Ramo de especialização: Imagem por Ressonância Magnética
Keywords
Ressonância magnética funcional fMRI Efeito BOLD Córtex visual Deficiência visual Deficiência visual congénita Deficiência visual adquirida Judo Functional mangetic resonance imaging Visual cortex Visual impairment Congenital visual impairment Acquired visual impairment
Citation
Correia CA. Avaliação por fMRI do córtex visual, motor e auditivo através de estimulação sensoriomotora e sonora em desportistas invisuais e desportistas sem deficiência visual [Dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa/Instituto Politécnico de Lisboa; 2014.
Publisher
Escola Superior de Tecnologia da Saúde de Lisboa