Linda S. Siegel

Phenotypic performance profile of children with reading disabilities: A regression-based test of the phonological-core variable-difference model.

In this study, we introduce a new analytic strategy for comparing the cognitive profiles of children developing reading skills at different rates: a regression-based logic that is analogous to the reading-level match design, but one without some of the methodological problems of that design. It provides a unique method for examining whether the reading subskill profiles of poor readers with aptitude/achievement discrepancy differ from those without discrepancy. Children were compared on a varied set of phonological, orthographic, memory, and language processing tasks. The results indicated that cognitive differences between these 2 groups of poor readers all reside outside of the word recognition module

IQ Is Irrelevant to the Definition of Learning Disabilities

The purpose of this article was to examine the logic and the empirical data supporting the proposition that intelligence tests are not necessary for the definition of a learning disability. Four assumptions of the use of IQ test scores in the definition of learning disabilities were examined. These assumptions were (a) IQ tests measure intelligence; (b) intelligence and achievement are independent, and the presence of a learning disability will not affect IQ scores; (c) IQ scores predict reading, and children with low IQ scores should be poor readers; and (d) reading disabled children with different IQ scores have different cognitive processes and information skills. It was argued that IQ scores measure factual knowledge, expressive language abilities, and short-term memory, among other skills, and that because children with learning disabilities have deficits in these areas, their scores may be spuriously low. It was also shown that some children with low IQ scores can be good readers, indicating that low IQ scores do not necessarily result in poor reading. Empirical evidence was presented that poor readers at a variety of IQ levels show similar reading, spelling, language, and memory deficits. On logical and empirical grounds, IQ test scores are not necessary for the definition of learning disabilities.

Home environment and cognitive development in the first 3 years of life: A collaborative study involving six sites and three ethnic groups in North America.

Attempted to examine the generalizability of environment/development relationships among 3 ethnic groups across the first 3 years of life. Social status did not show a consistent relationship to either quality of home environment or childrens developmental status across the various groups. Results indicated a fairly consistent relationship between HOME scores and childrens developmental status, although there were some ethnic and social status differences in the relationship. Measures of specific aspects of the childs home environment, such as parental responsivity and availability of stimulating play materials, were more strongly related to child developmental status than global measures of environmental quality such as SES. When the childs early developmental status and early home environment were both very low, the likelihood of poor developmental outcomes was markedly increased compared with cases when only one was low.

An Evaluation of the Discrepancy Definition of Dyslexia

The purpose of this study was to determine whether children with dyslexia, that is, children whose reading levels were significantly lower than would be predicted by their IQ scores, constituted a distinctive group when compared with poor readers, that is, children whose reading scores were consistent with their IQ scores. The performance of children with dyslexia, poor readers, and normally achieving readers was compared on a variety of reading, spelling, phonological processing, language, and memory tasks. Although the children with dyslexia had significantly higher IQ scores than the poor readers, these two groups did not differ in their performance on reading, spelling, phonological processing, or most of the language and memory tasks. In all cases, the performance of both reading disabled groups was significantly below that of nondisabled readers. The findings were similar whether absolute difference or regression scores were used. Reading disabled children, whether or not their reading is significantly below the level predicted by their IQ scores, experience significant problems in phonological processing, short-term and working memory, and syntactic awareness. On the basis of these data, there does not seem to be a need to differentiate between individuals with dyslexia and poor readers. Both of these groups are reading disabled and have deficits in phonological processing, verbal memory, and syntactic awareness.

Converging Evidence for Phonological and Surface Subtypes of Reading Disability.

Using regression-based procedures introduced by A. Castles and M. Coltheart (1993), the authors identified 17 phonological and 15 surface dyslexics from a sample of 68 reading-disabled 3rd-grade children by comparing them to chronological-age (CA) controls on exception word and pseudoword reading. However, when the dyslexic subtypes were defined by reference to reading-level (RL) controls, 17 phonological dyslexics were defined but only 1 surface dyslexic. When the CA-defined subtypes were compared to RL controls, the phonological dyslexics displayed superior exception word reading but displayed deficits in pseudoword naming, phonological sensitivity, working memory, and syntactic processing. The surface dyslexics, in contrast, displayed a cognitive profile remarkably similar to that of the RL controls.

Factors Related to English Reading Performance in Children with Chinese as a First Language: More Evidence of Cross-Language Transfer of Phonological Processing.

Parallel measures of phonological, syntactic, and orthographic processing skill and reading were administered in English and in Chinese to 65 children whose 1st language (LI) was Cantonese and whose 2nd language (L2) was English. Phonological skill was correlated across L1 and L2. Phonological skill in both L1 and L2 was correlated with L2 reading and contributed a unique variance to L2 reading, even though the childrens L1 was not written in an alphabetic orthography, whereas the 2nd language had an alphabetic orthography. This research adds to a growing body of evidence for cross-language transfer of phonological processing in L2 learning of English-as-a-Second-Language students.

Working memory, inhibitory control, and reading disability

The relationships among working memory, inhibitory control, and reading skills were studied in 966 individuals, 6—49 years old. In addition to a standardized measure of word recognition, they received a working memory (listening span) task in the standard, blocked format (three sets containing two-, three-, or four-item trials) or in a mixed format (three sets each containing two-, three-, and four-item trials) to determine whether scores derived from the standard format are influenced by proactive interference. Intrusion errors were investigated in order to determine whether deficits in working memory were associated with the access, deletion, or restraint functions of inhibitory control. The results indicated that deficits in working memory were characteristic of individuals with reading disabilities at all ages. These deficits may be associated with the access and restraint functions of inhibition. Working memory skills increased until the age of 19. The blocked format showed a gradual decline in adulthood whereas the mixed format did not. The different patterns suggest that the decline in working memory skills associated with aging may result from growing inefficiencies in inhibitory control, and not diminished capacity.

Linguistic Diversity and the Development of Reading Skills: A Longitudinal Study

The purpose of this study was to examine whether the same component processes are involved in reading acquisition for children with varying levels of proficiency in English in kindergarten and the first grade. The performance of 858 children was examined on tasks assessing basic literacy skills, phonological processing, verbal memory, and syntactic awareness. There were 727 children who were native English speakers (NS children) and 131 children who spoke English as a second language (ESL children). Although ESL children performed more poorly than NS children on most measures of phonological and linguistic processing in kindergarten and first grade, the acquisition of basic literacy skills for children from both language groups developed in a similar manner. Furthermore, alphabetic knowledge and phonological processing were important contributors to early reading skill for children from both language groups. Therefore, children learning English may acquire literacy skills in English in a similar manner to NS children, although their alphabetic knowledge may precede and facilitate the acquisition of phonological awareness in English.

Evidence for Superior Orthographic Skills in Dyslexics

The purpose of this study was to assess the development of both phonological and orthographic skills in normally achieving and dyslexic readers The subjects were 257 dyslexic and 342 normally achieving readers, matched at eight reading levels They were administered the Woodcock (1987) Word Attack Subtest, a measure of phonological skills requiring the reading of pseudowords, and an orthographic awareness task designed to measure awareness of the properties of English words and the probable sequences and positions of letters within words The dyslexics had significantly higher scores than the normally achieving readers on the orthographic awareness task However, the normally achieving readers had significantly higher scores on the Word Attack Subtest Therefore, the difficulties with phonological processing and the increased orthographic awareness of the dyslexics may indicate a reading strategy that relies more on the visual than the phonological features of words

Development of Phonological and Orthographic Processing in Reading Aloud, in Silent Reading, and in Spelling: A Four-Year Longitudinal Study.

The development of phonological and orthographic processing was studied from the middle of Grade 1 to the end of Grade 4 (age 6; 6-10 years) using the effects of regularity and of lexicality in reading aloud and in spelling tasks, and using the effect of pseudohomophony in a silent reading task. In all the tasks, signs of reliance on phonological processing were found even when indicators of reliance on orthographic processing appeared. Multiple regression analyses were conducted to determine which early skills predict later reading achievement. Pseudoword and irregular word scores were used as measures for phonological and orthographic skills, respectively. Only middle of Grade 1 phonological reading skills accounted for independent variance in end of Grade 4 orthographic skills. Conversely, from the middle to the end of Grade 1, and from the end of Grade 1 to the end of Grade 4, both orthographic and phonological skills accounted for independent variance in later orthographic skills. In the prediction of phonological skills, only the unique contribution of earlier phonological skills was significant. Thus, phonological and orthographic processing appear to be reciprocally related, rather than independent components of written word recognition. However, very early reliance on the phonological procedure seems to be the bootstrapping mechanism for reading acquisition.