Rapid Naming and Phonemic Awareness: Contributions to Reading,Spelling, and Orthographic Knowledge

The double-deficit hypothesis suggests that deficient skills on two dimensions, rapid naming and phonemic awareness, are associated with poor reading. We studied the reading, spelling, and orthographic skills of Grade 3 children who met our criteria for double asset (DA), single phonological deficit (PD), single naming speed deficit (NSD), and double deficit (DD) groups. Analyses of variance revealed main effects of each factor, oftentimes modified by significant interactions, on the varied achievement measures. All deficit groups performed below the DA children. Compared to children with NSD, children with PD (a) were less accurate decoders, (b) were faster readers, (c) had weaker spelling dictation, and (d) had comparably poor spelling recognition scores. Children with DD showed a mixed pattern of stronger, equal, or weaker skills compared to younger reading level controls.     

Remediating the core deficits of developmental reading disability: a double-deficit perspective

The double-deficit hypothesis (Wolf, 1997; Wolf & Bowers, 1999, this issue) contends that deficits in phonological awareness and deficits in visual naming speed represent two independent causal impediments to reading acquisition for children with developmental reading disabilities (RD). One hundred and sixty-six children with severe RD from 7 to 13 years of age were classified into three deficit subgroups according to a double-deficit framework. A total of 140 children with RD, 84% of the sample, were classified; 54% demonstrated a double deficit (DD), 22% a phonological deficit only (PHON), and 24% a visual-naming speed deficit only (VNS). Diagnostic test profiles highlighted the joint contributions of the two core deficits in depressing written language acquisition. The children in the DD group were more globally impaired than those in the other subgroups, and the VNS group children were the highest achieving and most selectively impaired readers. Following 35 hours of word identification training, sizable gains and significant generalization of training effects were achieved by all subgroups. A metacognitive phonics program resulted in greater generalized effects across the domain of real English words, and a phonological training program produced superior outcomes within the phonological processing domain. The greatest non-word reading gains were achieved by children with only phonological deficits.     

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.     

Developmental dyslexia: Related to specific or general deficits?

The present study was designed to examine the question of whether developmental dyslexia in 12-year-old students at the beginning of secondary education in the Netherlands is confined to problems in the domain of reading and spelling or also is related to difficulties in other areas. In particular, hypotheses derived from theories on phonological processing, rapid automatized naming, working memory, and automatization of skills were tested. To overcome the definition and selection problems of many previous studies, we included in our study all students in the first year of secondary special education in a Dutch school district. Participants were classified as either dyslexic, garden-variety, or hyperlexic poor readers, according to the degree of discrepancy between their word recognition and listening comprehension scores. In addition, groups of normal readers were formed, matching the poor readers in either reading age or chronological age. A large test battery was administered to each student, including phonological, naming, working memory, speed of processing, and motor tests. The findings indicate that dyslexia is associated with deficits in (1) phonological recoding, word recognition (both in their native Dutch and in English as a second language), and spelling skills; and (2) naming speed for letters and digits. Dyslexia was not associated with deficits in other areas. The results suggest that developmental dyslexia, at the age of 12, might be (or might have become) a difficulty rather isolated from deficiencies in other cognitive and motor skills.     

Phonological processing,speech perception,and reading disability: An integrative review

Relations between phonological processing and speech perception skills in reading-disabled children and adults are considered. Following Wagner and Torgesen (1987), phonological processing is comprised of at least three distinct though interrelated abilities--phonemic awareness, phonological recoding in lexical access, and short-term verbal memory skills. Speech perception skills may also represent two domains, speech perception and short-term memory. Studies of speech perception and word reading are critiqued. The interactions of speech perception, phonological processing skills, and word-reading abilities with development are considered in a preliminary model of reading. Although studies of phonological processing and speech perception in poor readers have thus far developed separately, experimenters in these isolated domains could benefit from the research findings in each and the unique paradigms each uses to investigate deficits in poor readers.     

Difficulties in L2 Hebrew Reading in Russian-speaking Second Graders

The present study examined factors that influence the process of learning to read in a second language. The Hebrew reading comprehension skills of 68 Russian-speaking children (mean age 7 years 6 months) were screened at the start of Grade 2. From this sample, 40 participants were selected: 20 successful learners and 20 unsuccessful learners. These two groups were then tested on a wide range of language skills (e.g., phonological processing, vocabulary, syntactic and morphological awareness) in both languages (Hebrew and Russian) and reading skills in Hebrew (e.g., reading speed and accuracy). Two factors, level of spoken Hebrew and phonological awareness deficits in both languages, were significant. Phonological awareness difficulties constituted the key factor associated with poor decoding whereas insufficient mastery of spoken Hebrew was important in the case of reading comprehension. An interesting dissociation was also found in our poor readers between impaired phonological awareness and other unimpaired phonological processing abilities such as oral pseudoword repetition and working memory. These findings suggest that, in addition to poor spoken L2 proficiency, poor readers are characterized more by a metalinguistic rather than a linguistic deficit in their native tongue.     

Word identification and reading disorders in the Spanish language

In this study, a reading-level-match design was used to test the hypothesis that children with reading disability (RD) are characterized by poor phonological skills, and that a developmental lag, as opposed to a specific deficit, will be found in transparent orthographies. Spanish has a transparent orthography and thus children with RD should not show severe difficulties in the use of the phonological route, as in the English language. A sample of 118 participants was selected and organized into three different groups: 40 with RD, 38 normal readers matched in age with the former, and 40 younger normal readers at the same reading level as those with RD. Two experiments were conducted to investigate the effects of lexicality, word frequency, word length, and positional frequency of syllables on lexical decision making and word-naming performance. While the participants were performing the naming task, we recorded what they read to subsequently analyze the form as well as the frequency of naming errors. The present study provides evidence for a deficit in phonological processing in a transparent orthography, particularly in nonword reading, because there were differences between the reading-level-matched groups.     

Structural invariance in the associations of naming speed,phonological awareness,and verbal reasoning in good and poor readers: A test of the double deficit hypothesis

The associations of multiple measures of speeded naming, phonological awareness, and verbal intelligence with word reading were examined in 51 poor readers and 74 good readers in third and fourth grade. Structural equation modeling was used to determine the extent to which these two groups exhibited structurally invariant patterns of associations among the constructs. Results revealed that for poor readers, both speeded naming and phonological awarencess were significantly associated with word reading, but verbal intelligence had no association with it. In contrast, for good readers, phonological awareness and verbal intelligence were significantly associated with word reading, but naming speed was not. Findings are discussed in light of the double deficit hypothesis.     

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.     

Phonological processing deficits in specific reading disability and specific language impairment: same or different?

The aim of this study was to determine if phonological processing deficits in specific reading disability (SRD) and specific language impairment (SLI) are the same or different. In four separate analyses, a different combination of reading and spoken language measures was used to divide 73 children into three subgroups: poor readers with average spoken language (SRD), poor readers with poor spoken language (SRD + SLI) and average readers with poor spoken language (SLI). These groups were compared on five phonological processing measures. The SRD group had deficits in neural representations of phonemes, phoneme discrimination, phoneme awareness and rapid naming. The SRD + SLI group had more severe deficits than the SRD group on half of these measures, as well as phonological short‐term memory. Children with SLI were free from phonological processing deficits. Thus, phonological processing deficits were the same or different in SRD and SLI, depending on how SRD and SLI were defined, and how phonological processing was measured.     

An examination of familial resemblance among subgroups of dyslexics

The goal of the present study was to ascertain whether developmental dyslexics and their affected parents evinced similar patterns of deficits in word recognition skills. Forty dyslexic children and both their biological parents were administered a battery of experimental measures of phonological and orthographic processing. Deficits in component skills were defined in terms of deviations from the performance of normal readers matched on reading achievement level. Four distinct patterns of deficits were found among both the dyslexics and their parents: a subgroup with a specific deficit in processing phonological codes; a subgroup with a specific deficit in processing orthographic codes; a subgroup with deficits in processing both phonological and orthographic codes; and a subgroup of individuals who did not significantly differ from normal readers at the same reading level in either processing domain. Although limited evidence for familial subgroup concordance was obtained in both the phonological and combined phonological subgroups, no concordance was observed among families classified into the orthographic or reading-achievement equivalent subgroups. It was concluded that all affected family members shared a propensity for a phonological deficit, and that some family members share a fundamental problem in processing orthographic information as well. This research was supported by a Biomedical Research Support Grant from the University of Southern California. The research reported in this paper was based on a Ph.D. thesis conducted by the first author at the University of Southern California.     

Dyslexia and the double deficit hypothesis

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, garden-variety 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.     

Cognitive profiles of poor readers of Kannada

The alphasyllabary of Kannada comprises more than 400 symbols called akshara; each symbol is visuo-spatially complex with a consistent representation at the dual levels of the syllable and the phoneme. We investigated reading difficulties in Kannada among 8–12 year old children by conducting a between-groups followed by a case series analysis. We compared the children with reading difficulties with same age competent readers and younger readers who were similar in language level, matched on measures of vocabulary, syntactic processing, and morphological processing. Reading difficulties were characterized by poor akshara knowledge. Concomitant impairments were in syllable and phoneme level phonological skills, in rapid naming and in oral language skills. The case series analysis highlighted the variability of profiles among poor readers with the most common impairments being in akshara knowledge and phonological processing. Sub-groups of poor readers showed additional deficits in oral language, rapid naming, and visual processing skills. Together our findings indicate that the core deficit associated with reading difficulty in the alphasyllabary of Kannada is in the phonological domain. However, accompanying deficits in related skills, including visual processing, can further inhibit reading attainment. The findings from this study support a multifactorial model of reading development.     

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.     

The contribution of orthographic and phonological processes to word reading in young Norwegian readers

The dissociation between phonological and orthographic processes in word reading was investigated in a study involving 147 children in grade 3. The criterion measure was a timed word reading test. Two tasks assessed phonological skills and two tasks assessed orthographical skills. Orthographic ability accounted for variance in word reading even after phonological ability had been controlled. Poor readers differed from skilled readers in the way phonological and orthographic factors were balanced. The relationship between the two factors was fairly strong among poor readers, whereas the correlation was low for more skilled readers. Furthermore, phonological factors played a much stronger role in explaining the variance in word reading among poor readers, while on the other hand, orthographic factors were more powerful among skilled readers.     

Specific deficits in component reading and language skills: genetic and environmental influences

Phonological coding, measured by the oral reading of nonwords, and orthographic coding, measured by the discrimination of words from homophonic nonwords (e.g., rane, rain), were compared for pairs of older children with reading disabilities (RD) and younger nondisabled readers matched on word recognition. Phonological coding was substantially lower for most children with RD, indicating a unique developmental deficit in phonological coding rather than an equal developmental lag across all component reading skills. Data from identical and fraternal twins indicated that the phonological coding deficit of the children with RD was highly heritable and accounted for most of the heritable variance in their word recognition deficits. The deficits of the twins with RD in segmental language skills (rhyming and phoneme segmentation) were related to the heritable variance in their phonological coding deficits. Orthographic coding was not significantly heritable, and it accounted for much of the environmental variance in word recognition deficits. Implications of the results for the remediation of reading disability are discussed.     

Heterogeneity in adult dyslexic readers: Relating processing skills to the speed and accuracy of oral text reading

Subgroups of Finnish dyslexic adults (N = 84)displaying, relative to each other, a distinctivecombination of accuracy and speed of oral text readingwere compared in phonological and orthographicprocessing, verbal short-term memory and readinghabits. Inaccurate phonological decoding appeared todetermine the number of errors made in text reading,while inability to utilize effectively rapid lexicalaccess of words manifested as slow text reading speed.Phonological and orthographic word recognitionprocesses were less tightly integrated among dyslexicthan normal readers. Our results indicate thatadvanced orthographic processing skills might help anumber of the dyslexic readers to compensate for theirserious phonological deficits. The subgroups alsodiffered from each other in reading habits. Arelatively fast reading speed, even with numerouserrors, appears to be more rewarding in everydayreading than a slower but more accurate readingstyle.     

A developmental perspective on dyslexic subtypes

In this paper we apply a developmental model of reading to the question of dyslexic subtypes. Groups of normal readers (n=40) and dyslexic children (n=50), matched on reading level and IQ, were given a comprehensive test battery measuring level of development of visual, phonological, and orthographic skills. As a group, dyslexics deviated from normal readers of equivalent reading achievement primarily in phonological skills (spelling-to-sound translation and phonemic analysis), although limited differences in knowledge of word-specific spellings were also observed. Dyslexics were superior to the younger normal readers in visual processing of print. Analysis of individual data by reference to the reading level control group revealed three major subgroups: a group with a specific deficit in phonological processing of print (52 percent), a group with deficits in processing both the phonological and orthographic features of printed words (24 percent), and a group with phonological deficits in language (8 percent). The remainder of the sample (16 percent) had specific deficits in visual or orthographic processing of print, in spelling, or did not differ from the control group. The data support the view that most developmental dyslexics have a specific language disorder involving some aspect of phonological processing. However, small subgroups with very different configurations of reading and nonreading difficulties may exist as well. This research was supported by an NICHD grant to the first author (USPHS grant 1 R23 HD20231).     

Evidence for phonological processing deficits in less-skilled readers

Although weaknesses in metaphonological skills are well-documented in poor readers, prior studies have yielded inconsistent findings as to whether less-skilled readers also have deficits in the more primary phonological processes entailed in verbal working memory and speech production tasks. The present study was designed to examine this issue by comparing less-skilled third-graders readers (n=30) with younger children at the same reading level (n=30) and with more-skilled agemates (n=30) on a variety of tasks that require phonological processing (i.e., three “verbal memory” tasks [word span, span with concurrent processing, pseudoword imitation] and three “speech production” tasks [word-pair repetition, tongue twisters, rapid naming]). The results were striking: the less-skilled third-grade readers had significantly lower accuracy scores than both their agemates and the younger normal readers on the word span, pseudoword imitation, word-pair repetition, and tongue twister tasks. Measures of accuracy were more related to reading ability than were measures of speed. Performance on a pseudoword imitation task was the variable most strongly linked to reading achievement.     

The effects of phonological transparency on reading derived words

The purpose of this study was to determine whether poor readers have more pronounced problems than average-reading peers reading derived words the base forms of which undergo a phonological shift when a suffix is added (i.e., shift relations as in “natural”), as compared to derived words whose forms are phonologically and orthographically transparent (i.e., stable relations, as in “cultural”). Two computer-based word recognition tasks (Naming and Lexical Decision) were administered to children with reading disability (RD), peers with average reading ability, and adults. Across tasks, there was an effect for transparency (i.e., better performance on stable than shift words) for both child groups and the adults. For the children, a significant interaction was found between group and word type. Specifically, on the naming task, there was an advantage for the stable words, and this was most noteworthy for the children with RD. On the lexical decision task, trade-offs of speed and accuracy were evident for the child reader groups. Performances on the nonwords showed the poor readers to be comparable to the average readers in distinguishing legal and illegal nonwords; further analyses suggested that poor readers carried out deeper processing of derived words than their average reading peers. Additional study is needed to explore the relation of orthographic and phonological processing on poor readers’ memory for and processing of derived words.