Abstract

Even if the ophthalmological aspects of developmental dyslexia are generally considered negligible in comparison to the cognitive and phonological ones, a growing body of evidence suggests in many patients the presence of deficiencies related to a neuronal subpopulation along the visual pathway. Still, even in the limited area of neuro-ophthalmological research, there is no general agreement on the mechanisms underlying reading impairment and on how the aetiological element determines the phenotype, that is to say the typical symptomatology. Nevertheless, the spatial and temporal vision in dyslexics seem to be defective. The purpose of this work is to report in a critical way the state of the art visual research in developmental dyslexia, without considering the aspects that go beyond our competence. In the second part of the treaties, the personal approach to the visuoperceptive impairment in this clinical condition is phenomenological rather than aetiological: it investigates the problem from the perceptive symptoms and signs rather than from the causal hypothesis and from the anatomofunctional demonstration. Without claiming to exhaust the subject, we have pursued a triple aim: trying to shed light on one of the most debated and controversial questions, providing a rigorous and comprehensive overview on the current acquisitions, and, why not, offering some cues to those who intend to contribute to solve the problem.

Contents

Introduction

Part I. To See is not Enough for Reading: State of the Art

Chapter 1. A Worldwide Problem
Chapter 2. Historical Background and Morphofunctional Studies
Chapter 3. Hromonal and Antigenic Factors
Chapter 4. Inheritance
Chapter 5. The Revival of the Visuoperceptive Hypothesis
Chapter 6. Contrast Sensitivity and Dyslexia
Chapter 7. Motion Perception and Dyslexia
Chapter 8. Visual Persistence and Dyslexia
Chapter 9. The Theory of the Deficit of the Magnocellular System: Lights and Shadows
Chapter 10. Eye Movements and Dyslexia
Chapter 11. Visual Attention and Dyslexia
Chapter 12. The Theory of the Deficit of the Temporal Rate Processing
Chapter 13. Dyslexia and Crowding
Chapter 14. One or More Dyslexias?
Chapter 15. The Visual Rehabilitation and its Controversies

Part II. Reading with their Eyes: A phenomenological Approach

Chapter 16. Premises for the Hypothesis of the Perceptive Shrinking
Chapter 17. Spatial Relationship Perception and the Eidomorphometry
Chapter 18. Spatial Relationship Perception in Dyslexics
Chapter 19. Does Vertical Anisotropy Lead to a Perceptual Distortion of the Shape of the Letters?
Chapter 20. Dialectical Suggestions
Chapter 21. Advancing a Visuoperceptive-Based Classification of Developmental Dyslexia
Chapter 22. Rehabilitating Spatial Relationship Perceptions. Avant-Gardes and Working Hypotheses

Conclusions

Epilogue

Appendices

Index