Several genes thought to confer susceptibility to dyslexia have been identified, and the purpose of this study is to 1) determine the expression pattern of one of these gene products and 2) characterize the function of the product of one of these genes, namely KIAA0319-Like (KIAA0319L), using the developing chick visual system as a model. Whole mount in situ hybridization was performed for KIAA0319L on embryonic day (E)3 – E5 and in situ hybridization on sections was performed at later stages. Engineered microRNA (miRNA) constructs targeting KIAA0319L were prepared and their specificity and efficiency for knocking down KIAA0319L were tested. miRNAs were electroporated in E5 optic tecta (OT). Embryos were sacrificed at E12. OT were removed, sectioned and analyzed. Results demonstrate that KIAA0319L is expressed in the developing chick visual system. Knockdown of KIAA0319L in the OT results in abnormal migration indicating that KIAA0319L is necessary for this process.

Reading disabilities (RD) have a significant genetic basis and chromosomes 3p12-q13 and 15q15-21 have shown replicated linkage to RD or reading measures. This study evaluated two RD candidate genes within these regions: DYX1C1 on chromosome 15q21 and ROBO1 on chromosome 3p12. DYX1C1 was tested for association using a family-based analysis of two independent samples. No statistically significant association was observed between the 10 tested DYX1C1 single nucleotide polymorphisms (SNPs) and RD or any of the quantitative traits. A review and meta-analysis of the potentially functional SNPs at the -3G/A and 1249G/T positions did not find strong support for these alleles as risk alleles for RD. ROBO1 was also evaluated in this study using SNPs that previously showed association with memory and reading measures in a population-based sample. None of the SNPs showed significant association with RD or any of the quantitative traits after correction for multiple testing.

Several genes thought to confer susceptibility to dyslexia have been identified, and the purpose of this study is to 1) determine the expression pattern of one of these gene products and 2) characterize the function of the product of one of these genes, namely KIAA0319-Like (KIAA0319L), using the developing chick visual system as a model. Whole mount in situ hybridization was performed for KIAA0319L on embryonic day (E)3 – E5 and in situ hybridization on sections was performed at later stages. Engineered microRNA (miRNA) constructs targeting KIAA0319L were prepared and their specificity and efficiency for knocking down KIAA0319L were tested. miRNAs were electroporated in E5 optic tecta (OT). Embryos were sacrificed at E12. OT were removed, sectioned and analyzed. Results demonstrate that KIAA0319L is expressed in the developing chick visual system. Knockdown of KIAA0319L in the OT results in abnormal migration indicating that KIAA0319L is necessary for this process.

Reading disabilities (RD) have a significant genetic basis and chromosomes 3p12-q13 and 15q15-21 have shown replicated linkage to RD or reading measures. This study evaluated two RD candidate genes within these regions: DYX1C1 on chromosome 15q21 and ROBO1 on chromosome 3p12. DYX1C1 was tested for association using a family-based analysis of two independent samples. No statistically significant association was observed between the 10 tested DYX1C1 single nucleotide polymorphisms (SNPs) and RD or any of the quantitative traits. A review and meta-analysis of the potentially functional SNPs at the -3G/A and 1249G/T positions did not find strong support for these alleles as risk alleles for RD. ROBO1 was also evaluated in this study using SNPs that previously showed association with memory and reading measures in a population-based sample. None of the SNPs showed significant association with RD or any of the quantitative traits after correction for multiple testing.

The purpose of this qualitative case study was to investigate the ways in which currently diagnosed dyslexic females, who navigated adolescence and their concomitant schooling without a definitive diagnosis of dyslexia, negotiated their identities in the figured world of school. To explore this phenomenon, it was necessary to understand the complexity of dyslexia as well as the theoretical underpinnings of identity construction, adolescence, and ―passing as literate.‖ This case study is informed by poststructuralist thought; through this lens I examine how my subjects perceived their worlds and how they negotiated the challenges associated with undiagnosed dyslexia. As they describe their positions in their figured worlds, I search for issues of power, identity and agency around which their lives appear to be organized. The answers to the following research questions were sought: (1) How do adult women who were undiagnosed dyslexic girls reflect upon their negotiations of identity in the figured world of school (Holland, Lachicotte, Skinner, & Cain (1998)? (2) Is there evidence that girls attempt to pass as literate? If so, what types of ―passing‖ attempts and techniques are used by dyslexic adolescent girls to appear more literate? Case study methodology offers the insight provided by detailed narratives of personal experiences. Data was collected by interviews, observations and researcher‘s field notes obtained through the stories of three adult dyslexic women. The data was analyzed for affirming or conflicting themes. The stories were retold in a chronological and thematic pattern describing the participants‘ experiences from different perspectives.

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This formative case study sought to explore the effectiveness of a remedial intervention based on Tier 2 word meanings for students whose primary deficit is phonological. Within the framework of a formative design research study, collaboration between a special education teacher and the researcher allowed for adaption and delivery of content while providing an opportunity to develop teacher capacity as well as student ability. The study found that focusing on the teaching of word meaning enhanced the remedial program due to the inclusion of a greater range of teaching strategies. Too few words were taught in order to bring about a significant improvement in vocabulary knowledge or spelling skill; however, most of the students believed they had improved in spelling and their attitude to writing was more positive at the end of the study. Several students showed improvement in written expression.

This formative case study sought to explore the effectiveness of a remedial intervention based on Tier 2 word meanings for students whose primary deficit is phonological. Within the framework of a formative design research study, collaboration between a special education teacher and the researcher allowed for adaption and delivery of content while providing an opportunity to develop teacher capacity as well as student ability. The study found that focusing on the teaching of word meaning enhanced the remedial program due to the inclusion of a greater range of teaching strategies. Too few words were taught in order to bring about a significant improvement in vocabulary knowledge or spelling skill; however, most of the students believed they had improved in spelling and their attitude to writing was more positive at the end of the study. Several students showed improvement in written expression.

There is a dearth of studies investigating attention and cognitive executive functions (EFs) in adults with Attention Deficit/Hyperactivity Disorder (AD/HD), dyslexia, and AD/HD with comorbid dyslexia. Of the available studies, few have compared cognitive performance based on comprehensive theoretical models of attention and EFs and addressed methodological limitations of past research (e.g., sample inclusion and task validity confounds). This dissertation reports the findings from two studies which examined attention performance and performance pertaining to EFs and related cognitive processes of vigilance and processing speed for four groups of postsecondary students, those with AD/HD, dyslexia, AD/HD with comorbid dyslexia, and normal controls. Using a diagnostically referred sample to ensure distinct disability groups and attention and EFs measures with demonstrated construct validity, cognitive task performance was examined in Study 1 based on Posner and Raichle’s (1994) model of attention which is composed of alerting, orienting, and executive attention networks. In Study 2, Pennington and Ozonoff’s (1996) conceptualization of EFs that includes inhibition, set shifting, and working memory components was applied to the students’ performance on attention, EFs (inhibition, set shifting, and working memory), vigilance, and processing speed measures. Results from the two studies showed that the groups with attention deficits (AD/HD and comorbid groups) exhibited vigilance, executive attention, and EFs deficits related to inhibition and set shifting. The groups with reading impairments (dyslexic and comorbid groups) displayed a specific EF deficit in auditory working memory and a processing speed response time deficit. The common etiology hypothesis, which posits that cognitive deficits in comorbid groups are the sum of deficits found in AD/HD and dyslexia alone, best described the performance of the comorbid group. The results are discussed with respect to identification/assessment, compensatory strategies, and educational interventions in postsecondary students with AD/HD and dyslexia. The studies emphasize that comparing cognitive performance based on comprehensive theoretical models of attention and EFs and addressing sample inclusion and task validity confounds can effectively delineate cognitive deficits in adults with AD/HD and dyslexia. / Thesis (Ph.D, Education) -- Queen's University, 2011-09-26 12:27:59.503