This study was designed to test the claim that a deficit in low-level visual processing is a major factor in the etiology of developmental dyslexia. The transient and sustained pathways are neuro-anatomical pathways which underlie low level visual processing. Dyslexics are hypothesized to suffer from a transient pathway deficit which manifests itself in reading difficulties. Normal and disabled adult readers were compared on two visual processing tasks. One task measured the contrast threshold of subjects for flickering sinewave gratings; normal and disabled readers did not differ in contrast sensitivity. On the second task--a visual search task--disabled readers were consistently slower than normal readers, rather than showing the pattern of performance predicted by the transient deficit model; the results provide little evidence for a transient pathway deficit. The results of this and related studies are discussed; it is concluded that empirical evidence for a transient pathway deficit in dyslexia is equivocal.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.69559 |
| Date | January 1993 |
| Creators | Hayduk, Steven J. |
| Contributors | Bruck, M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Arts (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001339960, proquestno: AAIMM87882, Theses scanned by UMI/ProQuest. |
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