Prediction of dyslexia in kindergarten boys

This study followed 163 boys from kindergarten through fourth grade. A battery of neurospychological and preacademic tests and electrophysiological measures (BEAM) were administered in kindergarten, and reading tests at grade 4, in an attempt to delineate precursors of dyslexia. Three of the kindergarten tasks (giving sounds associated with letters, rapid naming of numbers, and finger localization) differentiated dyslexics from normal readers with 98 percent correct classification. The tasks primarily involve grapheme-phoneme associations, storage and retrieval of phonological information in long-term memory, and verbal labeling. Results are interpreted as confirming the role played by phonological processing tasks in the prediction of dyslexia. Preliminary BEAM results for visual evoked potential topography suggest a significant increment in the distribution of this potential in the left parietal and frontal region, and, for auditory evoked potential topography, a significant difference between the two groups in the right posterior hemisphere. This work was supported in part by NIHCD grants RO1HD18761 to F.H. Duffy, RO1HD18654 to H. Als, and the Mental Retardation Grant P30HD18655 to C.F. Barlow.     

Automaticity, retrieval processes, and reading: a longitudinal study in average and impaired readers

In this longitudinal investigation, the development of word-retrieval speed and its relationship to reading was studied in 72 average and 11 severely impaired readers in the kindergarten to grade 2 period (5-8 years). Subjects received a battery of 3 reading measures and 4 continuous naming tests with varied stimulus requirements. Results indicated that the relationship of retrieval speed to reading is a function of development and the correspondence between higher- and lower-level processes in the specific retrieval and reading measures. As automaticity in retrieval developed in average readers, naming-speed/reading relationships moved from strong, general predictions to highly differentiated ones. The strongest correlations were between naming speed for graphological stimuli and lower-level reading tasks. Impaired readers performed slower than average readers on all naming measures across all years, particularly on graphological symbols. 3 dyslexic subgroups emerged: the largest was globally impaired across all naming rate and reading tasks; 2 smaller subgroups had early specific, retrieval-rate deficits and dissociated reading deficits.     

Individual differences in RAN and reading: a response timing analysis

Thirty 8–11‐year‐old children were administered tests of rapid naming (RAN letters and digits) and reading‐related skills. Consistent with the hypothesis that RAN predicts reading because it assesses the ability to establish arbitrary mappings between visual symbols and verbal labels, RAN accounted for independent variance in exception word reading when phonological skills were controlled. Response timing analysis of different components of RAN digits and letters revealed that neither average item duration nor average pause duration were unique predictors of reading skill. However, the number of pauses on digit naming predicted unique variance in exception word reading. Moreover, better readers paused more strategically than poorer readers (e.g. more often at the ends of lines). We suggest that rapid automatised naming may in part reflect differences in strategic control that are a result of differences in reading practice and experience.     

Syntactic and discourse skills in Chinese adolescent readers with dyslexia: a profiling study

This study aims to investigate the relation of syntactic and discourse skills to morphological skills, rapid naming, and working memory in Chinese adolescent readers with dyslexia and to examine their cognitive–linguistic profiles. Fifty-two dyslexic readers (mean age, 13;42) from grade 7 to 9 in Hong Kong high schools were compared with 52 typically developing readers of the same chronological age (mean age, 13;30) in the measures of word reading, 1-min word reading, reading comprehension, morpheme discrimination, morpheme production, morphosyntactic knowledge, sentence order knowledge, digit rapid naming, letter rapid naming, backward digit span, and non-word repetition. Results showed that dyslexic readers performed significantly worse than their peers on all the cognitive-linguistic tasks. Analyses of individual performance also revealed that over half of the dyslexic readers exhibited deficits in syntactic and discourse skills. Moreover, syntactic skills, morphological skills, and rapid naming best distinguished dyslexic from non-dyslexic readers. Findings underscore the significance of syntactic and discourse skills for understanding reading impairment in Chinese adolescent readers.     

Relationships among rapid digit naming, phonological processing, motor automaticity, and speech perception in poor, average, and good readers and spellers

In this article, we explore the relationship between rapid automatized naming (RAN) and other cognitive processes among below-average, average, and above-average readers and spellers. Nonsense word reading, phonological awareness, RAN, automaticity of balance, speech perception, and verbal short-term and working memory were measured. Factor analysis revealed a 3-component structure. The first component included phonological processing tasks, RAN, and motor balance. The second component included verbal short-term and working memory tasks. Speech perception loaded strongly as a third component, associated negatively with RAN. The phonological processing tests correlated most strongly with reading ability and uniquely discriminated average from below- and above-average readers in terms of word reading, reading comprehension, and spelling. On word reading, comprehension, and spelling, RAN discriminated only the below-average group from the average performers. Verbal memory, as assessed by word list recall, additionally discriminated the below-average group from the average group on spelling performance. Motor balance and speech perception did not discriminate average from above- or below-average performers. In regression analyses, phonological processing measures predicted word reading and comprehension, and both phonological processing and RAN predicted spelling.     

Rapid naming speed and Chinese character recognition

We examined the relationship between rapid naming speed (RAN) and Chinese character recognition accuracy and fluency. Sixty-three grade 2 and 54 grade 4 Taiwanese children were administered four RAN tasks (colors, digits, Zhu-Yin-Fu-Hao, characters), and two character recognition tasks. RAN tasks accounted for more reading variance in grade 4 than in grade 2, and graphological RAN tasks accounted for more reading variance than RAN Colors. After controlling for age, nonverbal intelligence, phonological sensitivity, short-term memory, and orthographic processing, RAN tasks were significant predictors of character recognition fluency in grade 2, and of both accuracy and fluency in grade 4.     

Neural Systems for Rapid Automatized Naming in Skilled Readers: Unraveling the RAN-Reading Relationship

The majority of children and adults with reading disabilities exhibit pronounced difficulties on naming-speed measures such as tests of rapid automatized naming (RAN). RAN tasks require speeded naming of serially presented stimuli and share key characteristics with reading, but different versions of the RAN task vary in their sensitivity: The RAN letters task successfully predicts reading ability, whereas the RAN objects task does not reliably predict reading after kindergarten. In this study we used functional magnetic resonance imaging to evaluate the neural substrates that may underlie performance on these tasks. In two scans during the same test session, adult, average readers covertly rapidly named objects or letters or passively viewed a fixation matrix of plus signs. For both rapid naming tasks compared with fixation, activation was found in neural areas associated with eye movement control and attention as well as in a network of structures previously implicated in reading tasks. This reading network included inferior frontal cortex, temporo-parietal areas, and the ventral visual stream. Whereas the inferior frontal areas of the network were similarly activated for both letters and objects, activation in the posterior areas varied by task. The letters task caused greater activation in the angular gyrus, superior parietal lobule, and medial extrastriate areas, whereas object naming only preferentially activated an area of the fusiform gyrus. These results confirm that RAN tasks recruit a network of neural structures also involved in more complex reading tasks and suggest that the RAN letters task specifically pinpoints key components of this network.     

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.     

Classification of Double Deficit Groups Across Time: An Analysis of Group Stability From Kindergarten to Second Grade

The Double Deficit Hypothesis of dyslexia is one approach to classifying students with reading disabilities. The theory offers four distinct groups of readers: (a) average readers, (b) students with phonological deficits, (c) students with naming speed deficits, and (d) students with double deficits: those having both (b) and (c). This study examines the stability of these groups from kindergarten to second grade. An initial sample of 214 students were tested at four time points on measures of rapid automatized naming, phonological awareness, and reading. Latent transition analyses were used to examine the stability of these groups over time. These analyses indicated moderate stability from kindergarten to second grade with the probability of movement between groups being higher in kindergarten and early first grade. The groups differed in reading achievement at each testing time, with the double deficit group obtaining the lowest scores. Implications for early assessment and intervention are discussed.     

The effect of orthographic depth on letter string processing: the case of visual attention span and rapid automatized naming

The present study investigated whether orthographic depth can increase the bias towards multi-letter processing in two reading-related skills: visual attention span (VAS) and rapid automatized naming (RAN). VAS (i.e., the number of visual elements that can be processed at once in a multi-element array) was tested with a visual 1-back task and RAN was measured in a serial letter naming task that introduced a novel manipulation (some letter sequences formed frequent words). Spanish-Basque and French-Basque bilingual children were tested at early (30 children in 1st and 2nd grade), and more advanced (24 children in 3rd, 4th and 5th grade) stages of reading acquisition to investigate whether they would be differently biased towards multi-letter processing due to reading in two shallow (Spanish, Basque), or a deep and a shallow (French, Basque) orthography. The French-Basque bilinguals, who read in a deep orthography, were expected to rely on larger orthographic units in reading and thus to be more biased towards multi-letter processing in both tasks. This was expected to be reflected by: (a) a uniform distribution of attention across letter strings in the VAS task, and (b) a greater interference of the embedded words on letter-by-letter naming in RAN, leading to longer naming times. The expected group differences were observed in the more advanced readers, with French-Basque bilinguals showing a wider distribution of VAS across letter strings and longer naming times in RAN.     

Brain Activity During Performance of Naming Tasks: Comparison Between Dyslexic and Regular Readers

This research was aimed at contributing to the current understanding of the underlying factors of naming speed and the causes of naming speed deficits. Forty regular readers and 40 dyslexic university students participated in the study. Electrophysiological (Event-Related Potentials [ERPs]) and behavioral measures were employed. Behavioral baseline tasks assessed general ability, reading skills, reading-related cognitive abilities, and standard Rapid Automatized Naming (RAN) and Rapid Alternating Stimulus tests. ERP tasks included letter and object naming tasks adapted for electrophysiological research presentation. The dyslexics were significantly slower and less accurate than the controls on most of the baseline measures. On all the naming tasks, the peak ERP latencies were elicited later, reaction times were longer, and the P300 latency width was wider among the dyslexics as compared to the regular readers. On the choice reaction time naming tasks, accuracy for both groups was almost perfect. When naming presentation time was controlled by the experiment, the dyslexics were significantly less accurate than the controls. Our data indicated that effective naming speed was related to an earlier P200 latency peak among regular readers and to an earlier P300 latency peak and narrower area component activation in the dyslexic group. The results from this study suggest that effective RAN speed among regular readers might be a result of efficient processing of RAN information at the input stage of stimulis perception and evaluation as well as of updating and processing the information in short-term memory among dyslexics.     

Development of and Relationship Between Phonological and Motivational Processes and Naming Speed in Predicting Word Recognition in Grade 1

In this 2-year longitudinal study the developmental relationships among letter knowledge, phonological awareness, rapid naming, and task orientation were examined, and linguistic-motivational pathways of word reading acquisition were traced from kindergarten to Grade 1 by means of structural equation modeling. The participants were 100 Finnish-speaking nonreaders. Results showed that kindergarten (5–6 years) letter knowledge predicted subsequent preschool (6–7 years) phonological awareness and task orientation. RAN was a unique longitudinal and concurrent predictor of word recognition, suggesting that rapid naming provides a reliable prediction of prospective word reading ability at least in a transparent language. Controlling for phonological awareness and rapid naming, task orientation contributed uniquely to the prediction of word reading competence, suggesting that motivational and linguistic factors are both at work as children face the gradually growing demands of learning to read and write in Grade 1.     

Revisiting the home literacy model of reading development in an orthographically consistent language

We examined the applicability of the Home Literacy Model in an orthographically transparent language (Greek). Seventy Greek children were followed from kindergarten until grade 4. In kindergarten they were tested in non-verbal intelligence, vocabulary, phonological sensitivity, rapid naming, and letter knowledge. The parents of the children also responded on a questionnaire regarding the frequency of storybook reading, the number of books at home, and the frequency of teaching letter names, sounds, and words. Reading fluency and comprehension were measured in grade 4. The results indicated that the early home literacy experience variables were related to the emergent literacy skills but did not directly predict future reading skills. Thus, the Home Literacy Model applies to consistent orthographies before any formal reading instruction takes place.     

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 Awareness and Rapid Automatized Naming Predicting Early Development in Reading and Spelling: Results from a Cross-Linguistic Longitudinal Study

In this study, the relationship between latent constructs of phonological awareness (PA) and rapid automatized naming (RAN) were investigated and related to later measures of reading and spelling in children learning to read in different alphabetic writing systems (i.e., Norwegian/Swedish vs. English). 750 U.S./Australian children and 230 Scandinavian children were followed longitudinally between kindergarten and 2nd grade. PA and RAN were measured in kindergarten and Grade 1, while word recognition, phonological decoding, and spelling were measured in kindergarten, Grade 1, and Grade 2. In general, high stability was observed for the various reading and spelling measures, such that little additional variance was left open for PA and RAN. However, results demonstrated that RAN was more related to reading than spelling across orthographies, with the opposite pattern shown for PA. In addition, tests of measurement invariance show that the factor loadings of each observed indicator on the latent PA factor was the same across U.S./Australia and Scandinavia. Similar findings were obtained for RAN. In general, tests of structural invariance show that models of early literacy development are highly transferable across languages.     

Predictors for grade 6 reading in children at familial risk of dyslexia

The present study investigates whether grade 6 reading outcomes, reading fluency, and reading comprehension can be predicted by grade 3 reading fluency, familial risk of dyslexia (FR), and grade 3 reading related skills: rapid automatized naming (RAN), phonological awareness (PA), and vocabulary. In a sample of 150 children, of whom 83 had a parent with dyslexia, correlation and regression analyses were performed. FR, measured on a continuous scale, was by itself related to all outcomes. However, FR did not explain any variance on top of grade 3 reading fluency. Grade 3 reading fluency strongly predicted grade 6 reading fluency and was also related to reading comprehension. RAN improved the prediction of grade 6 reading fluency, though the additional explained variance was small. Vocabulary and PA fully explained the variance that grade 3 reading fluency explained in grade 6 reading comprehension. Vocabulary explained a substantial amount of variance in grade 6 reading comprehension making it an interesting clinical target. As we used continuous measures of reading fluency and FR, our findings are not biased by distinct diagnostic criteria.     

Predicting word reading ability: a quantile regression study

Predictors of early word reading are well established. However, it is unclear if these predictors hold for readers across a range of word reading abilities. This study used quantile regression to investigate predictive relationships at different points in the distribution of word reading. Quantile regression analyses used preschool and kindergarten measures of letter knowledge, phonological awareness, rapid automatised naming, sentence repetition, vocabulary and mother's education to predict first‐grade word reading. Predictors generally varied in significance across levels of word reading. Notably, rapid automatised naming was a significant unique predictor for average and good readers but not poor readers. Letter knowledge was generally a stronger unique predictor for poor and average readers than good readers. Well‐known word reading predictors varied in significance at different points along the word reading distribution. Results have implications for early identification and statistical analyses of reading‐related outcomes. What is already known about this topic

• Early predictors of word reading are well established, with letter knowledge, phonological awareness and rapid automatised naming identified as key predictors.
• These relationships are primarily investigated in average readers, or in groups of good and poor readers separated by an arbitrary cut‐off score.

What this paper adds

• In this study, we used quantile regression to determine significant predictors of word reading across a range of word reading abilities.
• The quantile regression approach avoids the loss of power that can arise when creating subgroups and has none of the issues associated with the use of a single, arbitrary cut-off score to separate good and poor readers.
• Letter knowledge and phonological awareness were significantly predictive of word reading across the distribution of word reading abilities, whereas rapid automatised naming was significant only for good readers, and sentence recall was significant only for poor readers.

Implications for theory, policy and practice

• Results reinforce the usefulness of measures such as letter knowledge, phonological awareness and sentence repetition in the early identification of children at risk for reading disabilities.
• Results also suggest that measures of rapid naming may add little unique information in differentiating between children who subsequently read in the below‐average range.

     

Understanding the relations between RAN letter subtest components and word reading in first-grade students

First-grade students (N = 221) were individually tested on a battery of cognitive and achievement measures of verbal fluency, visual attention, phonological awareness, orthographic recognition, rapid automatized naming (RAN) of letters and objects, and reading. All tests were subjected to postacquisition scoring, and all RAN measures were segregated into measures of articulation time, pause time, and consistency of the pause time. Structural equation modeling demonstrated that word reading was directly and significantly predicted by RAN letter naming and general RAN cognitive processing time of objects. Moreover, RAN letter reading constructs were significantly and directly predicted by the latent variables of phonological awareness, orthographic recognition, and general RAN object articulation and cognitive processing times. RAN letter naming constructs were also significantly and indirectly predicted by visual attention. The reading model was found to be consistent with a total mediation of the relation of phonological awareness and reading through RAN letter naming and supported the validity of the RAN letter naming subtest as a basic letter reading test. These findings supported the double-deficit hypothesis for letter reading. We suggest that phonological memory is a basic factor underlying general RAN cognitive processing time of objects and domain-specific information associated with phonemes and their graphic representations.     

Deconstructing rapid automatized naming: Component processes and the prediction of reading difficulties

This study explores 1) the components of rapid automatized naming (RAN) by first analyzing the factorial associations between RAN tasks and various nonword decoding and processing speed measures and secondly, by exploring which of these process latent variables are uniquely associated with literacy in 65 below-average readers and spellers. In preliminary factor analyses, all speeded naming tasks loaded together (Factor 1: Rapid Naming); All tasks involving speeded alphanumeric naming loaded together (Factor 2: Alphanumeric Naming); Alphanumeric RAN tasks also loaded with nonsense word decoding (Factor 3: Decoding). The Alphanumeric Naming factor predicted 2% of unique variance in Literacy. Our results thus provide two new findings: 1) only very modest variation in Literacy is explained by aspects of RAN not primarily associated with either generic naming speed or decoding ability; 2) variation in other verbal forced choice response speed and response inhibition tasks are linked to reading through common variance in speeded naming tasks also shared by alphanumeric RAN tasks. Implications of these findings for theories of reading and individual differences are explored.     

Adult developmental dyslexia in a shallow orthography: Are there subgroups?

The existence and stability of subgroups among adult dyslexic readers of a shallow orthography was explored by comparing three different cluster analyses based on previously suggested combinations of two variables. These were oral reading speed versus accuracy, word versus pseudoword reading speed, and phonological awareness versus rapid naming. The three analyses were conducted with the same group of dyslexic adults. Each analysis produced three subgroups, corresponding to ones previously suggested in the literature. However, the subgroups had only little overlap from one analysis to another. Each clustering produced somewhat different subgroup profiles in phonological processing, reading, intelligence, temporal acuity, and sensory short-term memory. However, the shared difficulties of the solutions in several language-related and sensory tasks suggest the conclusion that developmental dyslexia does not causally consist of subgroups, at least in shallow orthographies. Further, the shared sensory difficulties suggest that impaired temporal acuity and sensory short-term memory may reflect the severity of a primary disorder that dyslexic readers cannot compensate by strategies.