Developmental Dyslexia: Research Methods and Inferences

Developmental dyslexia.

T he term developmental dyslexia ("specific reading retardation") refers to an unexpected difficulty in reading in children and adults who otherwise possess the intelligence, motivation, and schooling considered necessary for accurate and fluent reading. The concept has had a chequered career, with debates about its definition, origin, and causes, and indeed about its validity as a distinct ent...

Developmental Dyslexia

The possible causes and correlates of such difficulty have been the focus of a great deal of theorizing since before the turn of the twentieth century, when W. Pringle Morgan (1896) described a 14-year-old boy named Percy who suffered from pronounced difficulty learning to read and spell, despite normal achievement in other academic areas. Because he could find no evidence of definitive brain i...

Developmental Dyslexia

Developmental dyslexia and vision

Developmental dyslexia affects almost 10% of school-aged children and represents a significant public health problem. Its etiology is unknown. The consistent presence of phonological difficulties combined with an inability to manipulate language sounds and the grapheme-phoneme conversion is widely acknowledged. Numerous scientific studies have also documented the presence of eye movement anomal...

Crowding, reading, and developmental dyslexia.

We tested the hypothesis that crowding effects are responsible for the reading slowness characteristic of developmental dyslexia. A total of twenty-nine Italian dyslexics and thirty-three age-matched controls participated in various parts of the study. In Experiment 1, we measured contrast thresholds for identifying letters and words as a function of stimulus duration. Thresholds were higher in...