A developmental approach to reading disability: accuracy and speed criteria of normal and deficient reading skill.

The constructs of accuracy and speed were adopted as performance criteria against which to define 2 clinical samples of disabled readers. Accuracy-disabled subjects had failed to achieve reliable age-appropriate word recognition skills. Rate-disabled readers were age-appropriate in word recognition accuracy but deficient in reading speed. These disabled readers were compared to fluent normal children selected to be reading at the same level of accuracy as the rate-disabled subjects but at a significantly faster rate. All aspects of the accuracy-disabled subjects' reading systems proved deficient, and these children were less able to learn new sound-symbol associations in a task simulating initial reading acquisition. The rate-disabled subjects exhibited a basic deficit in word recognition speed, compromised accuracy when reading in context, and compromised spelling when competing visual patterns were available. A multidimensional oral language impairment was found to accompany the accuracy disability, while the rate disability appeared restricted to language in its visible form and the naming of visual representations. A visual naming speed impairment was associated with both profiles of deficient reading skill.