This study tested the role of visual processing speed and IQ in reading with 124 children either with or without reading disability. Results indicated that processing speed explains a significant amount of variance in reading comprehension, as does IQ. Path analyses indicated that the effect of IQ on reading is partially mediated by decoding in…

Comparison of 30 children having reading disabilities and average to above-average nonverbal IQ with control children revealed that the average-IQ children with reading disabilities differed from chronological controls, but not reading age controls, mainly in the area of successive processing. Results support the critical role of successive…

Word recognition data from identical and fraternal twins and siblings (N=172) indicated that the phonological coding deficit of children with reading disabilities was highly heritable. Orthographic coding was not significantly heritable. Poor readers with low IQs were superior to similar reading but average IQ readers in phonological coding.…

Forty adolescents with reading/spelling disabilities were assigned on the basis of IQ/achievement discrepancy scores to either a dyslexic or slow learner group. Significantly more females than males were in the slow learner category. Despite having lower IQs, the slow learning group had higher achievement levels, but group differences on…

Use of the discrepancy approach in defining learning disabilities is challenged, as intelligence tests do not measure potential, are not independent from what is measured by achievement tests, and are not powerful predictors of low reading performance. Use of intelligence tests in analysis, identification, and definition of learning disabilities…

In commenting on Linda Siegel's argument (in EC221505) that Intelligence Quotient is not causally related to reading difficulties, this paper argues that Intelligence Quotient is relevant to the definition of reading disabilities but that present knowledge may not justify its use in the selection of children for special services. (JDD)

This investigation (with 30 normal students and 30 students with reading disabilities, ages 7-15) examined the relationship between intelligence and phonological coding when ability was defined according to the Planning, Attention, Simultaneous, Successive (PASS) cognitive processing model. Findings indicate that phonological problems may not be…

In this commentary on Linda Siegel's paper (EC221505), it is argued that a minimum level of general ability is needed for successful reading performance. Above this threshold other kinds of intelligence are required and more important is the contribution of verbal efficiency, which is predicated on the covariance of phonology, morphology, and…

This study, with 93 third grade poor readers, 54 fifth grade poor readers (with and without reading/IQ discrepancies), and 147 nondisabled first graders, found poor readers significantly more impaired than the matched first graders on all measures of nonword reading thus supporting the hypothesis of a deficit in nonword reading skills not…

A study of 93 Spanish-speaking Latin American children of low socioeconomic background with reading difficulties found that, 4 years later, 17% had average reading ability, but 11% remained with severe reading difficulties. Characteristics examined include IQ, phonological processing, decoding ability, reading comprehension, and other verbal…

Fourteen poor-reading college students were assigned to a dyslexia group or a nonspecific reading-disabled group based on intelligence quotient (IQ). The groups were compared to controls on cognitive and reading-related skills. Results showed that poor decoding skill characterized the dyslexic reader, whereas the nondyslexic poor reader displayed…

This longitudinal study followed reading progress in 208 children with language impairments (either specific or nonspecific) compared to normal and low IQ controls from kindergarten through fourth grade. Children with language impairment in kindergarten, especially nonspecific language impairment, were at high risk of reading disabilities in…

This response to a paper by Linda Siegel (EC221505) on the relationship between Intelligence Quotient and learning disabilities addresses the differences between classification and identification, limitations in Siegel's conceptualization of intelligence, and the representation of the language and learning domains subsumed within the learning…

This study of 640 twins with reading disability and 436 controls (mean age 12) examined external validity of the distinction between specific reading retardation and reading backwardness, in 3 domains: genetic etiology, sex ratio and clinical correlates, and neuropsychological profiles. There was no evidence of differential genetic etiology of the…

A study was conducted to examine the relationship of perceptual motor skills as measured by the Bender Visual Motor Gestalt Test to word recognition, oral reading, and silent reading. In addition, perceptual motor skill and auditory comprehension were compared as correlates of the three reading variables. Subjects were 60 primary grade students in…