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Este trabalho tem como principal objectivo a avaliação das ondas cerebrais em indivíduos daltónicos, comparativamente com indivíduos normais recorrendo, à electroencefalografia. O daltonismo é uma perturbação da percepção visual caracterizada pela incapacidade de diferenciar todas ou algumas cores. É uma patologia principalmente associada a origem genética que é transmitida pelo cromossoma X, porém pode também resultar de lesões nos órgãos responsáveis pela visão, ou de lesões de origem neurológica. Os portadores do gene anómalo apresentam dificuldade na percepção de determinadas cores primárias (como o verde e o vermelho) o que se repercute na percepção das restantes cores do espectro. Esta perturbação é causada por ausência ou menor número de alguns tipos de cones ou por uma perda de função parcial ou total destes, normalmente associada à diminuição de pigmento nos fotorreceptores que deixam de ser capazes de processar diferencialmente a informação luminosa de cor. Para verificar a deficiência na percepção das cores existem diversos testes que podem ser efectuados. Neste trabalho, foram realizados apenas os três seguintes: placas de teste pseudo-isocromáticas de Ishihara, ‘ The City University Colour Vision Test’ e o teste de Farnsworth Munsell Hue de 100 tonalidades. Contudo, é ainda uma incógnita perceber se o daltonismo se traduz apenas numa questão genética ou se estará associado também a alterações nas ondas cerebrais referentes à percepção da cor. Para se poder constatar se de facto existe mais alguma alteração, para além da alteração na percepção visual das cores, há necessidade de explorar ainda este campo, tarefa que se revela facilitada através da utilização da electroencefalografia. Esta é já largamente utilizada para a realização de diversos testes e diagnósticos neurológicos, já que, permite o registo da variação da actividade eléctrica do cérebro, originado pela condução do impulso nervoso. A aquisição dos testes electroencefalográficos é aqui executada usando o PowerLab/4st propriedade da ADInstruments, e a sua análise é feita através de Fast Fourier Transform (FFT). Posteriormente, os dados adquiridos serão examinados tendo em conta duas grandezas principais, a frequência e a amplitude das ondas Alfa. Tentar-se-á indagar da existência de alguma relação qualitativa entre estas duas grandezas e a reacção à cor para indívíduos daltónicos, quando comparadas com a reacção de indivíduos normais.
This work has as main objective the assessment of brain waves in colorblind individuals, compared with normal individuals using the electroencephalography. Color blindness is a disorder of visual perception characterized by the inability to differentiate some or all colors. It is a pathology mainly associated with the genetic origin that is transmitted by chromosome X, but can also result from lesions in the organs responsible for vision, or lesions of neurological origin. Bearers of the abnormal gene exhibit difficulties in perception of certain primary colors (such as green and red) which affects the perception of the other colors of the spectrum. This disturbance is caused by absence or small number of some types of cones or by a loss of function, partial or total, of these, usually associated with a reduction of pigment in photoreceptors which shall no longer be able to handle differently the information of luminous color. To check the disability in the perception of colors there are several tests that can be carried out. In this work, were performed only the following three: Ishihara’s pseudoisocromatic test plates, ' The City University Color Vision Test' and the test of Farnsworth Munsell Hue of 100 tones. However, it is yet unknown realize if color blindness is translated only in a genetic issue or is also associated with changes in brain waves on the perception of color. To be able to see whether there is in fact more changes, beyond the ocular detection of colors, there is a need to explore this field, task which is facilitated through the use of electroencephalography. This technique is already widely used in the implementation of various tests and neurological diagnoses, which allows the registration of the variation of electrical activity of the brain, caused by nervous impulse conduction. The acquisition of electroencephalographic testing is here performed using the PowerLab/ 4st property of ADInstruments, and its analysis is performed by means of Fast Fourier Transform (FFT). Subsequently, the acquired data will be examined taking into account two main parameters, the frequency and the magnitude of the Alfa waves. We try to investigate the existence of any qualitative relationship between these two parameters and the reaction to colors for color blindness individuals, when compared with the normal individuals reactions.
This work has as main objective the assessment of brain waves in colorblind individuals, compared with normal individuals using the electroencephalography. Color blindness is a disorder of visual perception characterized by the inability to differentiate some or all colors. It is a pathology mainly associated with the genetic origin that is transmitted by chromosome X, but can also result from lesions in the organs responsible for vision, or lesions of neurological origin. Bearers of the abnormal gene exhibit difficulties in perception of certain primary colors (such as green and red) which affects the perception of the other colors of the spectrum. This disturbance is caused by absence or small number of some types of cones or by a loss of function, partial or total, of these, usually associated with a reduction of pigment in photoreceptors which shall no longer be able to handle differently the information of luminous color. To check the disability in the perception of colors there are several tests that can be carried out. In this work, were performed only the following three: Ishihara’s pseudoisocromatic test plates, ' The City University Color Vision Test' and the test of Farnsworth Munsell Hue of 100 tones. However, it is yet unknown realize if color blindness is translated only in a genetic issue or is also associated with changes in brain waves on the perception of color. To be able to see whether there is in fact more changes, beyond the ocular detection of colors, there is a need to explore this field, task which is facilitated through the use of electroencephalography. This technique is already widely used in the implementation of various tests and neurological diagnoses, which allows the registration of the variation of electrical activity of the brain, caused by nervous impulse conduction. The acquisition of electroencephalographic testing is here performed using the PowerLab/ 4st property of ADInstruments, and its analysis is performed by means of Fast Fourier Transform (FFT). Subsequently, the acquired data will be examined taking into account two main parameters, the frequency and the magnitude of the Alfa waves. We try to investigate the existence of any qualitative relationship between these two parameters and the reaction to colors for color blindness individuals, when compared with the normal individuals reactions.
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Keywords
Física da cor Ondas cerebrais Electroencefalografia Daltonismo