Dyslexia: a deficit in visuo-spatial attention, not in phonological processing
Related Experiment Video
Updated: Jun 17, 2026

Assessing Dyslexia at Six Year of Age
Published on: May 1, 2020
Trichur R Vidyasagar1, Kristen Pammer
1Department of Optometry & Vision Sciences, University of Melbourne, Parkville, Vic 3010, Australia. trv@unimelb.edu.au
Abstract:
Developmental dyslexia affects up to 10 per cent of the population and it is important to understand its causes. It is widely assumed that phonological deficits, that is, deficits in how words are sounded out, cause the reading difficulties in dyslexia. However, there is emerging evidence that phonological problems and the reading impairment both arise from poor visual (i.e., orthographic) coding. We argue that attentional mechanisms controlled by the dorsal visual stream help in serial scanning of letters and any deficits in this process will cause a cascade of effects, including impairments in visual processing of graphemes, their translation into phonemes and the development of phonemic awareness. This view of dyslexia localizes the core deficit within the visual system and paves the way for new strategies for early diagnosis and treatment.
Related Concept Videos
Learning Disabilities
Dyslexia
Dyslexia is a...
Language and Cognition
Visual Agnosia
Depth Perception and Spatial Vision
Attention-Deficit/Hyperactivity Disorder
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.
Higher Mental Functions of the Brain: Language
Language formation and comprehension take place in the dominant hemisphere. The dominant hemisphere is responsible for understanding the meaning of spoken, written, or sign language, as well as the ability to communicate. For most people, the left hemisphere is the dominant one. The right hemisphere, then, gives tone and emotional context to the...

