Evaluation of the multiple-deficit hypothesis among dyslexic Arabic-speaking children

This study examined the multiple-deficit hypothesis among Arabic-speaking elementary school students. A total of 90 students, divided into three main groups based on their performance on an Arabic word-reading task: dyslexic (n = 30), regular age-matched (n = 30), and 3rd-grade regular students, who were matched to the dyslexic group in regard to their reading proficiency level (n = 30). Participants underwent a nine-domain Arabic reading experiment that measured accuracy and fluency to evaluate general reading proficiency. The performance of Arabic dyslexic students was significantly worse than age-matched controls, but similar to young matched controls based on the reading level of each cognitive task. Moreover, dyslexic students showed deficits in three or more cognitive functions, depending on severity. This study adds to the limited empirical research on the double-deficit hypothesis and its extension to the multiple-domain model among young Arabic students.

Precursors of Reading Performance and Double- and Triple-Deficit Risks in Spanish

Early literacy skills serve as the best precursors of reading success and risk indicators of the double deficit and triple deficit hypotheses according to the spelling consistency of languages. Our study analyzes the predictive value of phonological awareness, naming speed, and orthographic skills for early reading in Spanish. Participants included 362 Spanish children aged 4 to 5 years. We used data analysis to examine the relationships between these precursors and fluency through a structural equation model and investigated the risk indicators of poor reading performance according to the double deficit and triple deficit hypotheses using binary logistic analysis. Our research delimits a model for the Spanish language that emphasizes the predictive value of phonological awareness, letter-naming fluency, and knowledge of graphemes in early reading. Letter-naming fluency is the best precursor to early reading experiences, and poor early reading performance in children is explained by deficits in phonological awareness, naming speed, and visual orientation. Our findings confirm the risk indicators of the triple deficit hypothesis in the early learning of reading in Spanish.

Effect of Cognitive Variables on the Reading Ability of Spanish Children at Age Seven

The objective of this study is to determine the contribution made by knowledge of letters, phonological awareness, phonological memory, and alphanumeric and non-alphanumeric rapid automatized naming at the ages of six and seven to the ability of Spanish children to read words at 7 years of age. A total of 116 Spanish-speaking school children took part in the study, from schools located in an average socio-cultural setting, without special educational needs. The reading ability of these pupils was evaluated at the age of seven, and cognitive variables were assessed at 6 and 7 years of age. Descriptive-exploratory analyses, bivariate analyses, and multivariate regressions were performed. The results show that cognitive variables measured at these ages contribute differently to the ability to read words at 7 years of age. Rapid naming does not seem to influence word reading; knowledge of letters no longer influences word reading as children grow older; and phonological awareness and phonological memory maintain their contribution to the explanation of word reading. These results indicate that reading in Spanish depends on different cognitive variables and that this relationship varies according to age. The findings have key educational implications in terms of teaching reading skills and the prevention of specific learning difficulties in Spanish Primary Education.

Developmental Trends of Visual Processing of Letters and Objects Using Naming Speed Tasks

Studying the typical development of reading is key to understanding the precise deficits that underlie reading disabilities. An important correlate of efficient reading is the speed of naming arrays of simple stimuli such as letters and pictures. In this cross-sectional study, we examined developmental changes in visual processing that occurs during letter and object naming from childhood to early adulthood in terms of behavioral task efficiency, associated articulation and eye movement parameters, and the coordination between them, as measured by eye-voice span in both the spatial and temporal domains. We used naming speed (NS) tasks, in which participants were required to name sets of letters or simple objects as quickly and as accurately as possible. Single stimulus manipulations were made to these tasks to make the stimuli either more visually and/or phonologically similar to one another in order to examine how these manipulations affected task performance and the coordination between speech and eye movements. Across development there was an increased efficiency in speech and eye movement performance and their coordination in both the spatial and temporal domains. Furthermore, manipulations to the phonological and visual similarity of specific letter and object stimuli revealed that orthographic processing played a greater role than phonological processing in performance, with the contribution of phonological processing diminishing across development. This comprehensive typical developmental trajectory provides a benchmark for clinical populations to elucidate the nature of the cognitive dysfunction underlying reading difficulties.

Examining the neural and cognitive processes that underlie reading through naming speed tasks

We combined fMRI with eye tracking and speech recording to examine the neural and cognitive mechanisms that underlie reading. To simplify the study of the complex processes involved during reading, we used naming speed (NS) tasks (also known as rapid automatized naming or RAN) as a focus for this study, in which average reading right-handed adults named sets of stimuli (letters or objects) as quickly and accurately as possible. Due to the possibility of spoken output during fMRI studies creating motion artifacts, we employed both an overt session and a covert session. When comparing the two sessions, there were no significant differences in behavioral performance, sensorimotor activation (except for regions involved in the motor aspects of speech production) or activation in regions within the left-hemisphere-dominant neural reading network. This established that differences found between the tasks within the reading network were not attributed to speech production motion artifacts or sensorimotor processes. Both behavioral and neuroimaging measures showed that letter naming was a more automatic and efficient task than object naming. Furthermore, specific manipulations to the NS tasks to make the stimuli more visually and/or phonologically similar differentially activated the reading network in the left hemisphere associated with phonological, orthographic and orthographic-to-phonological processing, but not articulatory/motor processing related to speech production. These findings further our understanding of the underlying neural processes that support reading by examining how activation within the reading network differs with both task performance and task characteristics.

Diagnostic implications of the double deficit model for young adolescents with dyslexia

Considerable support exists for both the phonological core deficit and the naming speed deficit models of dyslexia. The double deficit model proposed that many students with dyslexia might also be impaired in both underlying processes. Employing either performance thresholds (i.e., scores below the 16th or 25th percentile) or k-means clustering as classification methods, the current study investigated whether 154 young adolescents with dyslexia could be categorized into subtypes according to the presence or absence of phonological deficits alone, naming speed deficits alone, or a combination of the two and whether group composition changed depending on classification method. Results support the existence of both single and double deficit groups and confirm that those with both deficits are the most severely impaired across multiple measures. Contrary to previous research, most adolescents were classified as either naming speed only (about a third of the group) or double deficit when defining impairment using performance thresholds to classify groups. This may suggest that although early phonological deficits are amenable to remediation, identification of language symbols fails to become automatized in most individuals with dyslexia and may require more targeted intervention. Classification differences reported in the literature may depend on age and methods employed for classification.

Associative Cognitive Factors of Math Problems in Students Diagnosed With Developmental Dyscalculia

The Dutch protocol, 'Dyscalculia: Diagnostics for Behavioral Professionals' (DDBP protocol; Van Luit et al., 2014), describes how behavioral experts can examine whether a student has developmental dyscalculia (DD), based on three criteria: severity, discrepancy, and resistance. In addition to distinguishing the criteria necessary for diagnosis, the protocol provides guidance on formulating hypotheses by describing and operationalising four possible associative cognitive factors of math problems: planning skills, naming speed, short-term and/or working memory, and attention. The current exploratory and descriptive research aims to describe the frequency of these four primary associative cognitive factors in students with DD from the Netherlands. Descriptive data from 84 students aged 8-18 years showed that deficits in naming speed (in particular, in naming numbers) were the most frequent explanation of math problems in children with DD, followed by deficits in short-term/working memory and planning skills. Deficits in attention were the least frequent. The findings are explained in light of current literature, and suggestions for follow-up research are presented.

Identifying dyslexia risk for sport-related concussion management: Sensitivity and specificity of self-report and rapid naming

BACKGROUND

Dyslexia is the most common type of learning disability and studies have shown that student-athletes with learning disabilities sustain more concussions than their non-affected peers. However, current methods of dyslexia identification in college students are potentially invalid because they rely on students to self-report formal dyslexia diagnoses.

METHODS

To test the accuracy of self-report against two alternative methods of dyslexia screening, 94 college students completed three dyslexia symptom inventories, two rapid naming (RAN) tasks, and a standard word reading measure.

RESULTS

Reliability was acceptable for screening purposes on the inventories (α =.70, -.72), and excellent for RAN (α = .91, -.94). Specificity was acceptable (82.5%), but sensitivity was low (14.3%) when students self-reported suspected diagnoses of reading impairment. Sensitivity and specificity were higher for the digit RAN task (71 and 98%, respectively) compared to the letter RAN task (57 and 90%). Sensitivity (92.7%) and specificity (92.5%) were optimal when a cut-score of ≥27 seconds was used. A binary logistic regression showed digit RAN alone significantly predicted whether students were classified as typical or inefficient readers, p< .001, whereas the most reliable dyslexia inventory alone did not, p=.284. Including inventories along with RAN provided no additional predictive value.

CONCLUSION

Self-report inventories missed many cases of inefficient word reading. The digit RAN task classified 93.6% of the cases correctly compared to 72.3% for self-report inventory. Thus, we recommend that neuropsychologists working with college concussion management programs add to their baseline screening protocols the digit RAN task, which can be completed in less than one minute.

Naming speed as a predictive diagnostic measure in reading and attentional problems

This study aimed to describe and compare naming speed abilities in children diagnosed with either Reading Learning Difficulties (RLD) or Attention Deficit/Hyperactivity Disorder (ADHD), or comorbidity for both (ADHD+RLD). To examine the explanatory power of naming speed and ADHD symptomatology in predicting group associations (while controlling for gender and age), the "Rapid Automatized Naming and Rapid Alternating Stimulus Tests" (RAN/RAS) were utilized. A sample of 101 children (age range = 5-16 years) was divided into four groups: RLD (n = 14), ADHD (n = 28), comorbid (n = 19), and control (n = 40). There were statistically significant differences in RAN/RAS results among the diagnostic groups. Moreover, discriminant analysis revealed that naming speed tasks significantly predicted reading and attentional problems, especially at earlier ages. These results demonstrate the potential usefulness of RAN/RAS in the diagnosis of reading and attentional problems, particularly if the children are aged from 5 to 9.

Eye Movements and Articulations During a Letter Naming Speed Task

Naming speed (NS) refers to how quickly and accurately participants name a set of familiar stimuli (e.g., letters). NS is an established predictor of reading ability, but controversy remains over why it is related to reading. We used three techniques (stimulus manipulations to emphasize phonological and/or visual aspects, decomposition of NS times into pause and articulation components, and analysis of eye movements during task performance) with three groups of participants (children with dyslexia, ages 9-10; chronological-age [CA] controls, ages 9-10; reading-level [RL] controls, ages 6-7) to examine NS and the NS-reading relationship. Results indicated (a) for all groups, increasing visual similarity of the letters decreased letter naming efficiency and increased naming errors, saccades, regressions (rapid eye movements back to letters already fixated), pause times, and fixation durations; (b) children with dyslexia performed like RL controls and were less efficient, had longer articulation times, pause times, fixation durations, and made more errors and regressions than CA controls; and (c) pause time and fixation duration were the most powerful predictors of reading. We conclude that NS is related to reading via fixation durations and pause times: Longer fixation durations and pause times reflect the greater amount of time needed to acquire visual/orthographic information from stimuli and prepare the correct response.

Effects of phonological awareness and naming speed on mathematics skills in children with mild intellectual disabilities

OBJECTIVE

Both phonological awareness (PA) and naming speed have been identified as two skills related to the development of mathematics skills for children with and without learning disabilities. The purpose of the present study was to investigate the relationships between PA and colour naming speed for 265 elementary school students with mild intellectual disabilities (MID).

METHODS

Participants were assessed using the Comprehensive Test of Phonological Processes and the KeyMath Revised Diagnostic Inventory of Essential Mathematics.

RESULTS

Hierarchical regression analyses accounting for the effects of age indicated that children with MID rely on both PA and naming speed when solving mathematics problems, although PA was the more robust indicator of the two.

CONCLUSION

As a whole, these results suggest that children with intellectual disabilities evidence the same types of reading and math relationships as shown for other populations of children.

The relation between executive functioning, reaction time, naming speed, and single word reading in children with typical development and language impairments

BACKGROUND

Few investigations have examined the relationship between a comprehensive range of executive functioning (EF) abilities and reading.

AIMS

Our investigation identified components of EF that independently predicted single word reading, and determined whether their predictive role remained when additional variables were included in the regression analyses. This provided information about the EF processes that are related to reading, and the unity and diversity of EF.

SAMPLE

This study consisted of 160 children: 88 were typically developing with no language difficulties; 72 had language impairments.

METHOD

The assessments involved decoding, 10 measures of EF, reaction time, naming speed, non-verbal and verbal age-equivalent scores.

RESULTS AND CONCLUSIONS

In the first regression analysis, which only concerned the EF variables, the following verbal forms of EF had significant relationships with decoding: working memory, fluency, planning, and inhibition. Further regression analyses included additional predictor variables: reaction time, naming speed, and age-equivalent scores. These analyses indicated that most of the EF variables continued to predict decoding even when entered with competitor variables. Furthermore, after the entry of EF variables, there were no group differences in decoding (typical vs. language difficulties). We discuss the contribution of EF and other variables to reading abilities.

Developmental dyslexia and phonological processing in European Portuguese orthography

This study analysed the performance of phonological processing, the diagnostic accuracy and the influence on reading in children who were native speakers of an orthography of intermediate depth. Portuguese children with developmental dyslexia (DD; N=24; aged 10-12 years), chronological age (CA)-matched controls (N=24; aged 10-12 years) and reading level (RL)-matched controls (N=24; aged 7-9 years) were tested on measures of phonological processing (phonological awareness, naming speed and verbal short-term memory) and reading. The results indicated that the children with DD performed significantly poorer in all measures compared with the CA and RL. Phonological awareness and naming speed showed a high accuracy (receiver operating characteristics curve analysis) for discriminating the children with DD from the CA and RL, whereas the presence of abnormally low scores in phonological awareness and naming speed was more frequent in the DD group than in the controls and the normative population. Hierarchical linear regression analyses revealed that phonological awareness was the most important predictor of all reading accuracy measures, whereas naming speed was particularly related to text reading fluency.

Predictors of reading in Urdu: does deep orthography have an impact?

The aim of this study was to establish the extent to which rapid automatized naming (RAN) and non-word repetition (NWR) tasks predict reading fluency and reading accuracy in Urdu. One hundred sixty (8-9 years) children attending two types of schools (Urdu and English medium schools) were distributed into two groups, a control and a reading disability group on the basis of teacher's report. The results confirmed the role of RAN in predicting reading fluency in both groups. The role of NWR as a predictor of accuracy was also confirmed, although the strength of the relationship was modulated by RAN in the reading disability group. There are no tests available to identify children with reading problems in Urdu. Our study supports the validity of NWR and RAN tasks for the purposes of screening for reading deficits. The performance results also confirm the original grouping based on teacher reports. The study further highlights the importance of medium of instruction and increased oral language input in learning to read.

A model of phonological processing, language, and reading for students with mild intellectual disability

Little is known about the relationships between phonological processing, language, and reading in children with intellectual disability (ID). We examined the structure of phonological processing in 294 school-age children with mild ID and the relationships between its components and expressive and receptive language and reading skills using structural equation modeling. Phonological processing consisted of two distinct but correlated latent abilities: phonological awareness and naming speed. Phonological awareness had strong relationships with expressive and receptive language and reading skills. Naming speed had moderate relationships with these variables. Results suggest that children with ID bring the same skills to the task of learning to read as children with typical development, highlighting the fact that phonologically based reading instruction should be considered a viable approach.

Predicting word reading and comprehension with executive function and speed measures across development: a latent variable analysis

The present study explored whether different executive control and speed measures (working memory, inhibition, processing speed, and naming speed) independently predict individual differences in word reading and reading comprehension. Although previous studies suggest these cognitive constructs are important for reading, the authors analyze the constructs simultaneously to test whether each is a unique predictor. Latent variables from 483 participants (ages 8-16 years) were used to portion each cognitive and reading construct into its unique and shared variance. In these models 2 specific issues are addressed: (a) Given that the wide age range may span the theoretical transition from "learning to read" to "reading to learn," the authors first test whether the relation between word reading and reading comprehension is stable across 2 age groups (ages 8-10 and 11-16); and (b) the main theoretical question of interest: whether what is shared and what is separable for word reading and reading comprehension are associated with individual differences in working memory, inhibition, and measures of processing and naming speed. The results indicated that (a) the relation between word reading and reading comprehension is largely invariant across the age groups, and (b) working memory and general processing speed, but not inhibition or the speeded naming of non-alphanumeric stimuli, are unique predictors of both word reading and comprehension, with working memory equally important for both reading abilities and processing speed more important for word reading. These results have implications for understanding why reading comprehension and word reading are highly correlated yet separable