Evaluation of the double-deficit hypothesis subtype classification of readers in Spanish

The double-deficit hypothesis acknowledges both phonological processing deficits and serial naming speed deficits as two dimensions associated with reading disabilities. The purpose of this study was to examine these two dimensions of reading as they were related to the reading skills of 29 Spanish average readers and poor readers (mean age 9 years 7 months) who met the criteria for either single phonological deficit (PD), double deficit (DD), or no deficit. DD children were the slowest readers and had the weakest orthography processing skills. No significant differences were found between PD and DD groups on word and pseudoword reading. Word reading and reading comprehension skills were average or above average in the three studied groups. As in previous studies in transparent orthographies, word reading was not a salient problem for Spanish poor readers, whereas for the DD group, reading speed and orthographic recognition skills were significantly affected.     

Growth in Precursor and Reading‐Related Skills: Do Low‐Achieving and IQ‐Discrepant Readers Develop Differently?

Poor readers who met low achievement and IQ‐discrepancy definitions of reading disability were compared with nonimpaired readers on their development of eight precursor and reading‐related skills to evaluate developmental differences prior to students’ identification as reading disabled. Results indicated no evidence for differences between the two groups of poor readers in the development of the eight skills, with three exceptions. Students in the IQ‐discrepant group demonstrated greater growth in letter sound knowledge, greater mean performance in visual‐motor integration at the beginning of first grade, and greater deceleration in rapid naming of letters. When compared to the nonimpaired group, low‐achieving readers demonstrated poorer performance and development in all skills, while the IQ‐discrepant readers demonstrated poorer performance and development in phonemic awareness, rapid naming of letters and objects, spelling, and word reading. The largely null results for comparisons between the two groups of poor readers challenges the validity of the two‐group classification of reading disabilities based on IQ‐discrepancy.     

Lexical and nonlexical routes: a comparison between normally achieving and poor readers.

This study investigated qualitative differences in poor readers relative to normally achieving readers of the same reading level. Thirty-eight 9-year-old poor readers and forty 7- and 8-year-old reading-age-matched normally achieving readers from the United Kingdom were matched in phonemic processing and then given tests of memory span and visual discrimination of letter-like characters, were required to read different word types (regular, exception, and pseudoword), and were asked to complete a homophonic pseudoword test. The poor readers were worse at reading pseudowords compared to the controls, but this difference was unrelated to phonemic length of number of letters, or to the ease of producing analogies for the pseudowords. The results suggest that although there are no differences with reading-age controls in phonological processing, poor readers have worse grapheme-phoneme conversion skills and greater reluctance to relinquish the lexical route when appropriate. The results also showed that poor readers were slightly better at visual discrimination but had poorer memory spans.     

Longitudinal predictors of reading comprehension in French at first grade: Unpacking the oral comprehension component of the simple view

According to the simple view of reading (SVR), reading comprehension relies on “decoding” (pseudoword, word reading) and “oral comprehension” skills. Testing 556 French pupils, we aimed at unpacking these two components and tracking their longitudinal development in first grade. We have found that: (1) lower level language skills (vocabulary, syntax) and discourse skills (oral text comprehension) emerged as two dimensions of “oral comprehension”; (2) lower level language skills longitudinally predicted reading comprehension outcomes, above code-related skills; (3) decoding precursors (letter knowledge, naming speed and phonemic awareness) predicted reading comprehension directly, and indirectly, through decoding skills (pseudoword, word reading, text reading fluency); (4) Oral comprehension skills did not favour the development of decoding. Our results support the independency of the SVR components. However, we suggest that a more fine-grained conceptualisation of oral comprehension skills would help to better understand the individual and pedagogical factors influencing the early development of reading comprehension.     

Preschool prediction: Orthographic and phonological skills,and reading

Because of the research demonstrating the roles of phonological awareness, serial naming speed, and orthographic processing in reading, a test of each of these skills was added to a preschool screening battery. The main aim of the study was to determine whether these measures would contribute to the prediction of reading. The 118 subjects were first tested six months before kindergarten entry and were followed up 19 and 24 months later. Each additional screening test made a significant, independent contribution to the prediction of early first grade word reading/spelling, after the contributions of a parent rating of preschool reading ability (PRA), verbal IQ, socio-economic status (SES), and chronological age were accounted for. With letter naming and PRA, the additional tests were responsible for 62 percent of the variance. The orthographic test made the largest single contribution (32%) to the variance in word reading/spelling. Variables contributing significantly to the prediction of later first grade reading comprehension were (in order of proportion of the variance accounted for) letter naming, sentence memory, object naming speed, the orthographic test, and SES. The revised preschool screening battery correctly identified 91 percent of individual first grade good and poor readers. It was concluded that preschool measures of phonological awareness, serial naming speed, and orthographic processing make a strong contribution to prediction of first grade reading.     

The role of speed of processing, rapid naming, and phonological awareness in reading achievement

This study investigated the role of speed of processing, rapid naming, and phonological awareness in reading achievement. Measures of response time in motor, visual, lexical, grammatical, and phonological tasks were administered to 279 children in third grade. Measures of rapid object naming, phonological awareness, and reading achievement were given in second and fourth grades. Reading group comparisons indicated that poor readers were proportionally slower than good readers across response time measures and on the rapid object naming task. These results suggest that some poor readers have a general deficit in speed of processing and that their problems in rapid object naming are in part a reflection of this deficit. Hierarchical regression analyses further showed that when considered along with IQ and phonological awareness, speed of processing explained unique variance in reading achievement. This finding suggests that a speed of processing deficit may be an "extraphonological" factor in some reading disabilities.     

Reading comprehension skills of young adults with childhood diagnoses of dyslexia

This study explores the contribution of cognitive processes to comprehension skills in adults who suffered from childhood developmental dyslexia (CD). The performance of adults with CD (ages 17 to 23), chronological age-matched (CA) adults, and reading level-matched (RL) children was compared on measures of phonological processing, naming speed, working memory (WM), general knowledge, vocabulary, and comprehension. The results showed that adults with CD scored lower on measures of phonological processing, naming speed, WM, general knowledge, and vocabulary when compared to CA readers but were comparable to RL children on the majority of process measures. Phonological processing, naming speed, vocabulary, general knowledge, and listening comprehension contributed independent variance to reading comprehension accuracy, whereas WM, intelligence, phonological processing, and listening comprehension contributed independent variance to comprehension fluency. Adults with CD scored lower than CA adults and higher than RL children on measures of lexical processing, WM, and listening comprehension when word recognition and intelligence were partialed from the analysis. In summary, constraints in phonological processing and naming speed mediate only some of the influence of high-order processes on reading comprehension. Furthermore, adults with CD experience difficulties in WM, listening comprehension, and vocabulary independently of their word recognition problems and intellectual ability.     

Do different components of working memory underlie different subgroups of reading disabilities?

The purpose of this study was to determine the components of working memory (WM) that underlie less skilled readers' comprehension and word recognition difficulties. Performance of 3 less skilled reading subgroups---children with reading disabilities (RD) in both word recognition and comprehension; children with comprehension deficits only; and children with low verbal IQ, word recognition, and comprehension (poor readers)--was compared to that of skilled readers on WM, short-term memory (STM), processing speed, executive, and phonological processing measures. Ability group comparisons showed that (a) skilled readers outperformed all less skilled readers on measures of WM, updating, and processing speed; (b) children with comprehension deficits only outperformed children with RD on measures of WM, STM, phonological processing, and processing speed; and (c) children with RD outperformed poor readers on WM and phonological processing measures. A hierarchical regression analysis showed that (a) subgroup differences on WM tasks among less skilled readers were moderated by a storage system not specific to phonological skills, and (b) STM and updating contributed significant variance to WM beyond what was contributed by reading group classification. The latter finding suggested that some differences in storage and executive processing emerged between skilled and less skilled readers that were not specific to reading.     

Orthographic awareness,phonemic awareness,syntactic processing,and working memory skill in hyperlexic children

Children classified as hyperlexic learn to readwords spontaneously before age five, areimpaired in both reading and listeningcomprehension, and exhibit word recognitionskills above their linguistic and cognitiveabilities. Despite their strong wordrecognition skills, previous studies have shownthat the phonemic awareness skills ofhyperlexic children are low and notcommensurate with their word reading skill, inpart because of their limited comprehension of phonemic awareness tasks. Heretofore, a verylimited number of studies have investigateddirectly the orthographic processing, syntacticprocessing, and working memory skills ofchildren with hyperlexia. In the presentstudy, measures of orthographic processing,syntactic processing, and working memory skillwere administered to three hyperlexic childrenand three normally achieving readers; inaddition, measures of phonemic awareness,academic achievement, and cognitive abilitywere also administered. Results showed thatthe hyperlexic children performed aboveexpectations on the orthographic processingmeasures based on their cognitive andlinguistic abilities. The children withhyperlexia did not exhibit orthographic skillsthat were superior to the normally achievingreaders, although ceiling effects on theorthographic tasks may not have allowed them todemonstrate this skill. The three children withhyperlexia achieved lower scores than thenormally achieving readers on the syntacticprocessing measures and had great difficulty onthe phonemic awareness measures. Only one ofthe three hyperlexic children performed at alevel consistent with that of normallyachieving readers on the working memorymeasures. Findings suggest the hyperlexicchildren had levels of orthographic processingsimilar to that of normally achieving readers,read words using strategies similar to those ofnormal readers, and had phonemic awarenessskill that appears to be adequate for wordanalysis but could not be demonstrated ontraditional phonemic awareness measures.     

Tracing symbol naming speed's unique contributions to reading disabilities over time

The contributions of naming speed measured on both serial-list and various discrete-trial formats to several reading subskills were examined longitudinally to determine their impact independent of other reading-related skills on reading disabilities. Tests of symbol naming speed, phonological awareness, vocabulary, memory span and coding speed were given to 38 poor and average readers when they were in Grades 2, 3 and 4. Grade 4 poor readers were discriminated from moderately poor or good readers on serial-list and discrete-trial naming speed tests in all grades. In addition, phonological awareness and vocabulary, but not memory span or coding speed, discriminated groups. These variables in Grade 2 contributed unique variance to reading scores in Grade 4 in differing patterns. Hypotheses about the nature of the reading — naming speed relationship are discussed.     

Longitudinal Stability of Reading-Related Skills and Their Prediction of Reading Development

Individual differences in word recognition, spelling, and reading comprehension for 324 children at a mean age of 16 were predicted from their reading-related skills (phoneme awareness, phonological decoding, rapid naming, and IQ) at a mean age of 10 years, after controlling the predictors for the autoregressive effects of the correlated reading skills. There were significant and longitudinally stable individual differences for all four reading-related skills that were independent from each of the reading and spelling skills. Yet the only significant longitudinal prediction of reading skills was from IQ at mean age 10 for reading comprehension at mean age 16. The extremely high longitudinal latent-trait stability correlations for individual differences in word recognition (.98) and spelling (.95) left little independent outcome variance that could be predicted by the reading-related skills. We discuss the practical and theoretical importance of these results and why they differ from studies of younger children.     

Enabling skills in early reading acquisition: A study of children in Latvian kindergartens

Preschool children in Latvia were tested in order to examine the relationships among various enabling skills and early reading performance. A principal component analysis indicated three factors: a phonemic awareness factor, a naming factor, and a short-term memory factor. Multiple regression analyses with word identification and sentence comprehension as dependent variables yielded further support to the powerful role played by phonemic awareness in explaining variance in both these aspects of reading. Unexpectedly, neither naming nor short-term memory contributed to explain unique variance in word and sentence reading. The Latvian orthography is very consistent, and our results provide further evidence to the importance of phonemic awareness in early reading acquisition especially in a transparent language. Therefore, the tasks used when assessing phonemic awareness can be very useful when screening children at risk for developing reading problems. Enhancing children's letter knowledge and phonemic awareness skills should be a priority goal in the kindergarten classroom.     

Predicting reading ability over the long term: The changing roles of letter naming,phonological awareness and orthographic processing

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.     

Qualitative and quantitative differences among dyslexic,normal, and nondyslexic poor readers

This study tested the hypothesis that when a stringent criterion of normal IQ is applied in the selection of dyslexic readers, and when dyslexics, nondyslexic poor readers, and normal readers are matched on reading comprehension — rather than word reading — significant differences among these groups can be demonstrated. Two groups of poor readers from primary grades, one with normal IQ (dyslexics) and the other with below-average IQ (nonspecific reading disabled, NSRD) were matched for reading comprehension with a group of younger normal readers. The dyslexic group was found to be inferior to the other two groups in tests of decoding and spelling. The dyslexic readers were more context-dependent for word recognition than the other two groups. The NSRD group did not differ from the normal readers in these aspects but had the worst performance on a test of inferential comprehension. It was concluded that dyslexics differ from normal readers and low-IQ poor readers in word and nonword reading skills and context-dependency for reading. A group of six adult dyslexics were also found to be deficient in decoding skills. A lack of unanimity in the use of certain terminology, a substantial age difference between low-IQ poor readers and normals, and the difference in the criteria used for matching the different groups could be factors that can explain the disagreements seen between the findings of the present study and those reported by some other studies. Potential problems associated with reading-age matched experimental design are discussed.     

The Nature of and Factors Related to Reading Difficulties Among Adolescents in a Transparent Orthography

We examined the nature of and factors related to adolescents’ reading difficulties in a highly transparent orthography. We compared word, pseudoword, and text reading speed and accuracy, rapid naming (RAN) and phonological processing between poor readers (n?=?80) and normally developing readers (n?=?189). Reading problems were manifested in reading speed and in timed pseudoword reading accuracy. RAN predicted speed, and phonological processing predicted accuracy of reading in both groups. Among poor readers, RAN also explained reading accuracy. For the normally developing sample, phonological processing also predicted reading speed.     

Orthographic processing is a key predictor of reading fluency in good and poor readers in a transparent orthography

We used structural equation modeling to investigate sources of individual differences in oral reading fluency in a transparent orthography, Russian. Phonological processing, orthographic processing, and rapid automatized naming were used as independent variables, each derived from a combination of two scores: phonological awareness and pseudoword repetition, spelling and orthographic choice, and rapid serial naming of letters and digits, respectively. The contribution of these to oral text-reading fluency was evaluated as a direct relationship and via two mediators, decoding accuracy and unitized reading, measured with a single-word oral reading test. The participants were “good” and “poor” readers, i.e., those with reading skills above the 90th and below the 10th percentiles (n = 1344, grades 2–6, St. Petersburg, Russia). In both groups, orthographic processing skills significantly contributed to fluency and unitized reading, but not to decoding accuracy. Phonological processing skills did not contribute directly to reading fluency in either group, while contributing to decoding accuracy and, to a lesser extent, to unitized reading. With respect to the roles of decoding accuracy and unitized reading, the results for good and poor readers diverged: in good readers, unitized reading, but not decoding accuracy, was significantly related to reading fluency. For poor readers, decoding accuracy (measured as pseudoword decoding) was related to reading fluency, but unitized reading was not. These results underscore the importance of orthographic skills for reading fluency even in an orthography with consistent phonology-to-orthography correspondences. They also point to a qualitative difference in the reading strategies of good and poor readers.     

Phonological and orthographic processing: Their roles in reading prediction

Ninety-six children were administered an orthographic test as preschoolers and two measures of nonphonemic phonological awareness (syllable segmentation, rhyme detection) in midkindergarten. The power of the three measures to predict reading at grades 1, 3, and 7 was examined. With earlier reading level, preschool verbal IQ and age, and verbal memory controlled, both phonological measures added significant variance to grade 1 word reading, and syllable segmentation also contributed to reading comprehension, but neither measure accounted for variance in reading at grades 3 and 7. The orthographic measure contributed significant variance to grade 1 word reading, and also to reading vocabulary and reading comprehension at grades 3 and 7, with the proportion of variance in reading comprehension increasing with grade level. When early (grade 1) and late (grade 7) poor readers were compared, late poor readers were significantly higher than early poor readers on a first grade phonological test, but significantly lower on a seventh grade orthographic measure. Evidence suggested that a late reading comprehension deficit may be due to poor orthographic processing skills in some children, but to a phonological and general verbal deficit in others.     

Early Literacy From a Longitudinal Perspective

The goal of this longitudinal study was to examine which skills in early literacy determine the development of word recognition, reading comprehension, and spelling in the 2nd grade of the elementary school. A cohort of pupils was followed and tested during the 2nd year of kindergarten and the beginning of the 1st and 2nd grade. It appeared that mainly 2 skills determined the development of word recognition: rapid naming of letters and knowledge of letters. Reading comprehension was predicted to a large extent by vocabulary, rapid naming of letters, letter knowledge, and phonemic awareness. The skills that determined the development of spelling were rapid naming of numbers and letter knowledge.     

The Contribution of Naming Speed to the Simple View of Reading

The purpose of this study was to investigate whether naming speed makes a contribution to the prediction of reading comprehension, after taking into account the product of word decoding and listening comprehension (i.e., the Simple View of Reading; [Gough, P.B. & Tunmer, W.E. (1986). Remedial and Special Education 7, 6–10]), and phonological awareness. In grade 3, word decoding was measured with the Woodcock [(1998). Woodcock Reading Mastery Tests – Revised. Circle Pines, MN: American Guidance Services]. Word Identification and Word Attack subtests, listening comprehension with the Woodcock (1991) [Woodcock Language Proficiency Battery – Revised. Chicago: Riverside Publishing Company] test of Listening Comprehension, naming speed with a picture naming task, and 4 measures assessed phonological awareness. Reading comprehension was assessed in grades 3, 4, and 5 with the Woodcock (1998) Passage Comprehension subtest and in grade 5 with the Gates–MacGinitie reading test. The Simple View was evaluated twice: first, with a pseudoword measure for decoding (Grapheme–Phoneme-conversion product) and, second, with a word identification measure for decoding (word recognition product). Hierarchical regression and commonality analyses indicated that the decoding and listening comprehension products accounted for considerable variance in reading comprehension. Naming speed had a small but significant effect after accounting for the Grapheme–Phoneme-conversion product (2–3%), but little effect after accounting for the word-recognition product (0–2%). Subgroup analyses indicated that naming speed had its primary effect for less able readers. Commonality analyses supported the interpretation that naming speed contributes after the Grapheme–Phoneme-conversion product but not after the word recognition product because naming speed has already had its effect upon word recognition. These results indicate that it is important how the Simple View decoding term is defined, and that the Simple View may be incomplete, especially for less able readers.