As a specific reading disability with a neurobiological origin, developmental dyslexia is distinct from reading difficulties due to sensory impairments in vision or hearing. The disability is commonly attributed to a core deficit in phonological processing, the understanding of how phonemes, syllables and words are used in a language. Dyslexia is a complex genetic disorder with a strong genetic component; nine susceptibility loci (DYX1-9) have been identified with eight other dyslexia linkages lacking gene symbols also reported. The statistical methods of linkage and association were employed to investigate the genetic susceptibility for phonological coding dyslexia (PCD), a common form of dyslexia characterized by difficulties in single word decoding and resulting from deficits in phonological processing. A genome-wide non-parametric linkage (NPL) study and four targeted fine-mapping family-based association studies were performed to locate the genes predisposing to PCD in 101 Canadian families with multiple affected members. The NPL scan identified suggestive evidence for linkage with PCD at the two novel regions 16p12 and 4q12-q13, and provided independent confirmation of linkage to the well-replicated DYX3 locus (at 2p21). Some support for linkage was noted at a further five regions previously linked to dyslexia, while no linkage was detected at five other reportedly-linked regions, in particular, no linkage to DYX2 (6p22.2). Four regions (16p12, 2p21, 4q12-q13 and 6p22.2) were tested for association with PCD in 83 trios, a subset of the 101 families, using the transmission disequilibrium test (TDT) and the affected family-based controls (AFBAC) test. Association was detected in each of the three PCD-linked regions in the NPL scan; none of the tested marker alleles was associated with PCD in the 6p22.2 region. Four candidate genes were identified, two of which belong to the same gene family, with a possible role in the neurodevelopmental mechanisms underlying reading.

The present study was designed to investigate the relationship of inferred hemisphericity for spatial and verbal processing in normal and dyslexic male readers using a dichotomous tactile stimulation technique. The study was a modification of Witelson's (1974; 1976) studies using non-verbal (shapes) and verbal (letters) stimuli. An additional verbal (objects) task, in which subjects recognized and verbally reported the object's use, was devised specifically for the study.One purpose of the study was to determine whether older normal readers would differ from dyslexics of the same age and younger normal readers on their accuracy of recognition of stimuli. Another purpose was to examine the differences between left and right hand responses to the verbal tasks (letters and objects) to determine if the objects task was a better measure of verbal or left hemispheric functioning than the letters task.Subjects were right-handed males who demonstrated average or above average intelligence and manifested no sensory impairment or primary emotional disturbance. Older normal readers and dyslexics were 9 to 13 years while younger normal readers were 5 to 7 years old. A total of 66 subjects qualified for and completed the study.Analysis of variance was employed to test the main hypothesis using a three-factor design with repeated measures on the same subjects (Winer, 1971). No differences were found in the accuracy of response among groups suggesting greater within than between group variance. A significant Task x Hand interaction (P/-.05) was explained by greater inferred right hemisphere involvement in the processing of the shapes and letters tasks while greater inferred left hemisphere involvement in the processing of the objects task was confirmed for the normal groups. Dyslexics, however; demonstrated more inferred right hemisphere involvement for all the tasks (shapes, letters and objects) suggesting the use of a spatial-holistic cognitive strategy for stimuli whether non-verbal or verbal.

No description available.

The research reported here attempts to identify those reading processes common to both alphabetic readers and readers of Chinese logographic characters, and those processes unique to Chinese reading. Three types of evidence are presented: (1) experimental studies of normal Chinese readers; (2) clinical and experimental investigations of Chinese patients with acquired dyslexic symptoms; (3) a survey of developmental dyslexia in China. Like alphabetic readers, Chinese readers show independent procedures for mapping from orthography to meaning and from orthography to sound. Also like alphabetic readers, the mapping to sound can be accomplished by both a lexical and a sublexical procedure. The special characteristics of Chinese script are analysed and their significance in reading processes are revealed. The research is presented in six chapters. Chapter 1 is the background of this study which contains a general review of reading studies of Chinese and other scripts, the main theoretical issues and the objectives of this study. Chapter 2 presents a new analysis of statistical properties of Chinese characters including the consistency of phonetic radicals. Chapter 3 presents experiments on reading Chinese characters by normal Chinese readers. In these studies, phonological recoding is demonstrated; the lateralization of reading Chinese characters is investigated; and finally, the errors of normal subjects' reading is examined. Chapter 4 contains a clinical study on Chinese acquired dyslexic patients. In this study, several Chinese acquired dyslexic symptoms are reported for the first time. Analogues of surface and deep dyslexia in Chinese patients are described for the first time. This supports the idea of independent lexical and sublexical procedures for mapping from orthography to sound. However, Chinese surface and deep dyslexia show features distinct from their alphabetic counterparts. In addition, it is also revealed that there are some special dyslexic symptoms which are predictable from the characteristics of Chinese script which I term associative dyslexia and compound dyslexia. Chapter 5 contains a survey on developmental dyslexia among 8106 Chinese pupils in which the ratio of developmental dyslexia is found to be lower (1.92%) than in alphabetic children. Chapter 6 presents the theoretical implications of the studies taken together for Chinese reading and for reading generally.

As a specific reading disability with a neurobiological origin, developmental dyslexia is distinct from reading difficulties due to sensory impairments in vision or hearing. The disability is commonly attributed to a core deficit in phonological processing, the understanding of how phonemes, syllables and words are used in a language. Dyslexia is a complex genetic disorder with a strong genetic component; nine susceptibility loci (DYX1-9) have been identified with eight other dyslexia linkages lacking gene symbols also reported. The statistical methods of linkage and association were employed to investigate the genetic susceptibility for phonological coding dyslexia (PCD), a common form of dyslexia characterized by difficulties in single word decoding and resulting from deficits in phonological processing. A genome-wide non-parametric linkage (NPL) study and four targeted fine-mapping family-based association studies were performed to locate the genes predisposing to PCD in 101 Canadian families with multiple affected members. The NPL scan identified suggestive evidence for linkage with PCD at the two novel regions 16p12 and 4q12-q13, and provided independent confirmation of linkage to the well-replicated DYX3 locus (at 2p21). Some support for linkage was noted at a further five regions previously linked to dyslexia, while no linkage was detected at five other reportedly-linked regions, in particular, no linkage to DYX2 (6p22.2). Four regions (16p12, 2p21, 4q12-q13 and 6p22.2) were tested for association with PCD in 83 trios, a subset of the 101 families, using the transmission disequilibrium test (TDT) and the affected family-based controls (AFBAC) test. Association was detected in each of the three PCD-linked regions in the NPL scan; none of the tested marker alleles was associated with PCD in the 6p22.2 region. Four candidate genes were identified, two of which belong to the same gene family, with a possible role in the neurodevelopmental mechanisms underlying reading.

Thesis (Ph.D.)--Tufts University, 2003. / Adviser: Maryanne Wolf. Submitted to the Dept. of Child Development. Includes bibliographical references (leaves 164-190). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 3 uppsatser.

Theses (Ed.S.)--Marshall University, 2004. / Title from document title page. Includes abstract. Document formatted into pages: contains 21 pages. Bibliography: p. 20-21.

Thesis (Ph.D.)--University of Western Australia, 2007.

Theses (Ed.S.)--Marshall University, 2004. / Title from document title page. Includes abstract. Document formatted into pages: contains 22 p. Bibliography: p. 21-22