The achievement of 1,075 school children was followed to the end of grade 7 or 8. Retrospective details of birth, medical history, and infant adaptive behavior, as well as current information about preschool behavior, were provided by parents before kindergarten entry when their children were ages four to five. At that time, each child was given language, preacademic, and visual-motor tests, and a short-form verbal IQ was obtained. For grades 1 to 8, a mean 6.9 percent qualified as low in arithmetic (including 3.9 percent low only in arithmetic) and 9 percent as low in reading (including 6 percent low only in reading). Groups of children with persistent disability in arithmetic only (2.3 percent), reading only (6.6 percent), and arithmetic plus reading (3.4 percent) were compared on all variables, and gender differences were examined. The specific arithmetic group was superior to the other two groups in preschool verbal IQ and language, and had suffered more birth problems and illness. As found by Rourke and his colleagues (e.g., Rourke and Finlayson 1978) for older children, boys with a specific arithmetic disability showed a preschool profile with high verbal scores and low nonverbal scores. Many gender differences were found for the total sample, but few for the learning disability subgroups.

The double deficit hypothesis (Bowers and Wolf 1993) maintains that children with both phonological and naming-speed deficits will be poorer readers than children with just one or neither of these deficits. In the present study, we drew on this hypothesis to help understand why some children have a serious reading impairment. In addition, by adding an orthographic factor, we extended it to a triple deficit hypothesis. Participants were 90 children aged 6 to 10 years. Dyslexic children, whose reading was low for age and for expected level, gardenvariety poor readers, reading-level matched younger children, and low verbal IQ good readers, were compared. The dyslexic group was significantly lower then the garden-variety poor readers and the low verbal IQ good readers on most measures, and lower than the younger group on phonological measures. Findings support the double deficit hypothesis of Bowers and Wolf, and also the triple deficit hypothesis. Most of the poorest readers, nearly all of whom qualified as dyslexic, had a double or triple deficit in phonological, naming-speed, and orthographic skills. Conclusions were that dyslexia results from an overload of deficits in skills related to reading, for which the child cannot easily compensate.

A cohort of 92 children was followed through sixth grade to investigate the relationship of preschool skills and first grade phonological awareness to reading and spelling. In particular, the focus was on the changing roles of letter naming, orthographic awareness, and phonological processing in prediction, as reading experience increased. Preschool letter naming was a consistently significant predictor of reading vocabulary, reading comprehension, and spelling at each grade level, but the preschool orthographic task contributed most to reading comprehension and spelling at the higher grades. Conversely, the contribution of the first grade phonemic awareness measures to reading skills dropped sharply after third grade, although they continued to contribute to spelling prediction. When preschool precursors of phonological processing were examined, letter naming was found to be a predictor of first and third grade phonemic awareness. Findings confirm the importance of letter naming as a predictor and of the role of phonemic awareness in early reading acquisition, but also highlight the contribution of orthographic processing skills to later reading.