Phonological dyslexia and dysgraphia—a developmental analysis

Phonological dyslexics (Ph-DYS) are characterized by a phonological deficit, while surface dyslexics (S-DYS) are characterized by an orthographic deficit. Four issues were addressed in this study. First, we determined the proportion of Ph-DYS and S-DYS in a population of French dyslexics by applying Castles and Coltheart's (1993) regression method to two previously unused diagnostic measures: pseudo-word and irregular-word processing time. Thirty-one dyslexics were matched to 19 average readers of the same age (10 years, CA controls) and to 19 younger children of the same reading level (8 years, RL controls). Compared to CA controls, there were more Ph-DYS than S-DYS. Compared to RL controls, there were still a high number of Ph-DYS; however, the S-DYS profile almost disappeared. Next, we examined the reliability of these subtypes across different measures of phonological and orthographic skills. Compared to RL controls, both groups of dyslexics were found to be impaired only in phonological skills, either in processing time (Ph-DYS) or in accuracy (S-DYS). Then we assessed the moment at which the two dissociated profiles emerged in the course of cognitive development. In order to do so, we examined earlier longitudinal data, collected when the children were 7 and 8 years old, and found that only the S-DYS's orthographic deficit increased with development. Last, we looked at whether the Ph-DYS and S-DYS profiles were associated with other specific cognitive deficits. Specific deficits in phonemic awareness and in phonological short-term memory were found for both Ph-DYS and S-DYS. These data suggest that developmental dyslexia could be largely accounted for by an underlying phonological impairment.

Introduction The purpose of this study is to present three case studies of developmental dyslexia in dual-language learners (DLLs) and our assessment process. We identify how phonological and orthographic deficits influence reading outcomes. We review the literature on theoretical models of bilingualism and reading models of developmental dyslexia to guide the assessment process through a multicomponential approach. We point out differences in the manifestation of dyslexia in more and less transparent writing systems. We suggest that reading instruction in Spanish can afford benefits to English-Spanish DLLs with developmental dyslexia. Method The study included three participants, two in fifth grade (10.3-11.7 years) and one in college (18.7 years). The assessment battery included reading nonwords and sight words (Test of Word Reading Efficiency); reading accuracy, fluency, and comprehension (Gray Oral Reading Tests-Fourth Edition); phonological awareness subtests (Comprehensive Test of Phonological Processing); and rapid automatized naming tests. A language and reading history interview was elicited from the mothers. In addition, we analyzed the participants' phonemic and word errors in reading. Results Our three participants showed core phonological deficits, with decreased performance in decoding nonwords and low accuracy in reading aloud. In spite of their reading and writing deficits, reading comprehension was within average levels for the three participants in this study. Conclusions We show the importance of assessing reading processes in students with a history of reading and writing problems. Our findings are based on three single case studies and are not generalizable. Our aim is to stimulate questions and research on dyslexia and the particular needs of DLLs.

Aim: Developmental dyslexia is basically defined as a learning disorder characterized by reading, writing, spelling, and word comprehension difficulties. Phonological deficits in dyslexia are well established in literature, yet, research also indicates some visuospatial difficulties. The aim of this study was to examine the visuospatial functions in Turkish children with dyslexia and to show the interrelationship of visuospatial perception, visual memory, and executive functions. Methods: The sample of this study was composed of 20 children (9 female and 11 male) with developmental dyslexia and 20 age-matched controls (11 female and 9 male). The children in dyslexia group were previously diagnosed as dyslexic according to Diagnostic and Statistical Manual of Mental Disorder-IV criteria in a private rehabilitation center. Rey-Osterreich complex figure test (ROCF), Clock Drawing Test (CDT), and Judgment of Line Orientation test (JLOT) were used to evaluate visuospatial functions of the children. Results: Comparison analyses showed that dyslexia group significantly differed from the control group in all visuospatial test scores (P < 0.05 for all). In addition, a positive correlation was present between JLOT score and ROCF direct copying score, ROCF immediate memory score, ROCF delayed memory score, and CDT score for the dyslexic group (P < 0.05 for all). Conclusion: Our findings confirm the presence of visuospatial problems in dyslexia and highlight the importance of interaction between perceptual and executive processes indicating a more fundamental cognitive deficit.

This study deals with improving stuudents’ achievement in reading comprehension through natural approach. The objective of this study is to iinvestigate whether there is any significant improvement of the students’ achievement in reading comprehension when it is taught by using natural approach. The subject of the study was Grade XI students of Nasrani 3 Private Senior High School (Sekolah Menengah Atas Swasta Nasrani 3) Medan. There were thirty one students. They were taught by using Natural Approach. The instrument for data collection were teacher made test, observation sheet and questionaire. The techniques of data analysis applied were quantitative and qualitative. In analysing the data, the students were given three reading tests namely, Orientation Test, Test Cycle I and Test Cycle II. The mean of the students’ score for the first reading test as Orientation test was 51.61 the second reading test as Cycle I test was 66.61 and the third reading test as Cycle II test was 76.61. The total percentage of the improvement from the first reading test to the third was 77.41%. the conclusion is that the procedures of natural approach can improve the students’ achievement in reading comprehension. The qualitative data shows that the students were enthusiastic and interested in reading comprehension. It is suggested that teachers should apply Natural Approach as one of the media in improving students’ achievement in reading comprehension. Keywords: Reading, Natural Approach, classroom Action Research.

Phonological alexia and agraphia are acquired disorders characterized by an impaired ability to convert graphemes to phonemes (alexia) or phonemes to graphemes (agraphia). These disorders result in phonological errors typified by adding, omitting, shifting, or repeating phonemes in words during reading or graphemes when spelling. In developmental dyslexia, similar phonological errors are believed to result from deficient phonological awareness, an oral language skill that manifests itself in the ability to notice, think about, or manipulate the individual sounds in words. The Auditory Discrimination in Depth (ADD) program has been reported to train phonological awareness in developmental dyslexia and dysgraphia. We used a multiple-probe design to evaluate the ADD program's effectiveness with a patient with a mild phonological alexia and mixed agraphia following a left hemisphere infarction. Large gains in phonological awareness, reading and spelling nonwords, and reading and spelling real words were demonstrated. A follow-up reassessment, 2 months posttreatment, found the patient had maintained treatment gains in phonological awareness and reading, and attained additional improvement in real word reading.

Students in an undergraduate human development course (N = 215) participated in a brief assessment of their reading (comprehension level, reading speed, comprehension rate) and multiple-choice test-taking skills on the second day of class. Students first read a one-page, 400-word passage unrelated to the course and then answered 10 multiple-choice questions over the passage without referring back to the passage. To control for test-taking skills, students also answered 10 multiple-choice questions from an equivalent passage they did not read. Videotapes of student participation permitted individual assessment of time required to complete each phase. Subsequently, during the semester students took five 50-item multiple-choice exams over the major units in the course. Results showed that the brief reading comprehension measures predicted multiple-choice exam performance and that comprehension level accounted for most of the variance in exam performance. Discussion focuses on enhancing brief reading assessment procedures by including direct measures of comprehension. Keywords: Reading Comprehension, Reading Comprehension Rate, Test-taking, College Grades ********** Several measures predict success in college courses, including measures of critical thinking, generic vocabulary, background knowledge, and reading comprehension (Behrman & Street, 2005; Jackson, 2005; Williams & Eggert, 2002; Williams, Oliver, Allin, Winn, & Booher, 2003a; Williams, Oliver, Allin, Winn, & Booher, 2003b; Williams, Oliver, & Stockdale, 2004; Williams & Worth, 2002). Not all course activities require high-level critical thinking, an advanced vocabulary, or background knowledge, but virtually all course activities require student reading of course material (Behrman & Street, 2005). Thus, the current study focused on reading comprehension measures as predictors of success in a large undergraduate course. Although reading comprehension is predictive of student success (Jackson, 2005), reading speed or fluency may also be related to comprehension levels, effort required to read, and reinforcement for reading (Skinner, Pappas, & Davis, 2005). Researchers have measured reading fluency by timing students' oral reading and scoring word accuracy. These data are then used to calculate words correct per minute (WCM), which has been shown to correlate with reading comprehension and other reading skills as measured via standardized, norm-referenced tests with strong psychometric properties (Deno & Merkin, 1977; Deno, Merkin, & Chiang, 1982; Fuchs, & Fuchs, 1992; Fuchs, Fuchs, Hosp, & Jenkins, 2001; Fuchs, Fuchs, & Maxwell, 1988; Hintze & Shapiro, 1997; Jenkins & Jewell, 1993). These studies provide support for several theories that suggest causal mechanisms for explaining the relationship between reading speed and comprehension. Students who read rapidly and are not required to apply their attention or other cognitive resources (e.g., working memory) towards decoding words have more cognitive resources available to apply towards comprehension. Additionally, as time passes information may become inaccessible (e.g., fading from working memory). Thus, as they read, rapid readers may have access to more information from material read earlier than slow readers, which may enhance their ability to synthesize information as they progress through passages (LaBerge & Samuels, 1974; Perfetti, 1992; Rasinski, 2004; Stanovich, 1986). Reading, like many other skills, improves as people choose to spend more time engaged in the activity (Daly, Chafouleas, & Skinner, 2005; Stanovich, 1986). Even when slower readers are able to comprehend the material at the same level as rapid readers, rapid readers are more likely to choose to read the assigned work because it requires less time and effort and results in a higher rate of reinforcement (Billington, Skinner, Hutchins, & Malone, 2004; Skinner, 1998; Skinner, 2002; Skinner, Neddenriep, Bradley-Klug, & Ziemann, 2002; Skinner, Wallace, & Neddenriep, 2002). …

The marked degree of heterogeneity in persons with developmental dyslexia has motivated the investigation of possible subtypes. Attempts have proceeded both from theoretical models of reading and the application of unsupervised learning (clustering) methods. Previous cluster analyses of data obtained from persons with reading disabilities have suffered from the inherent limitations of unsupervised learning methods. Specifically, the reliability and stability of cluster solutions have proven difficult to determine. Recent developments in the clustering literature have addressed these concerns by permitting checks on the internal validity of the solution. Resampling methods produce consistent groupings of the data independent of initialization effects, while the gap statistic provides a confidence measure for the determination of the optimal number of clusters present in the data. Combining these methods produces a robust data-driven classification that can be compared with theoretically based subtypes to produce better-informed models of developmental dyslexia. The present study is a novel application of resampling (bootstrap aggregating or bagging) methods and the gap statistic to the subtyping of children with developmental dyslexia. The specific aims of this study are: (1) to illustrate the use of bagging methods and the gap statistic in multivariate data obtained from children with developmental dyslexia; and (2) to compare the bagged clustering thresholded by the gap statistic against the predictions of the double-deficit hypothesis. The double-deficit hypothesis is a prominent theoretical model of developmental dyslexia, which predicts three subtypes: phonological, rate, and phonological-rate impaired readers. Three simulated data sets with known cluster structure were created to check the validity and illustrate the utility of the bagged clustering with the gap statistic in data with known structure. Subsequently, a clinical database of standardized test data (eight tests) from 93 children with developmental dyslexia was clustered using these methods. This procedure was repeated on a database of 93 children without reading disability matched for gender and age as a control. Finally, the clustering was repeated on the entire database of 186 participants. Cluster solutions were obtained for an increasing number of clusters (1-10) and were tested against the null hypothesis that no subtypes were present, i.e. the data represented a single cluster. Four clusters were identified in the children with developmental dyslexia. There was no evidence of significant cluster structure in the children without dyslexia. Two clusters were identified when children with and without reading impairments were considered together. Among the participants with developmental dyslexia, there was evidence of a phonological-deficit cluster, a rapid-naming cluster, and a cluster showing both depressed phonological processing and rapid naming. These accounted for 73 of the 93 participants (78%). All three are predicted by the double-deficit hypothesis. The fourth cluster consisted of children with normal phonological and rapid naming ability incommensurate with their high verbal ability. An analysis of variance with post-hoc multiple comparisons demonstrated that the phonological, rapid-naming, and double deficit clusters did not differ significantly in age, but the fourth cluster was comprised of significantly older children. The mixed data set revealed two clusters. One cluster consisted almost entirely of the double-deficit and phonological subtypes. The other consisted of the participants without dyslexia and the children with dyslexia demonstrating either a single rapid naming deficit or standardized test scores in the normal range. A silhouette analysis indicated that the four-cluster solution for the children with developmental dyslexia was superior to the two-cluster solution obtained for the entire data set. The study provides support for the presence of distinct subtypes in children with developmental dyslexia and for the double-deficit hypothesis. Specifically, this study finds three subtypes predicted by the double-deficit hypothesis without the assumption of an a priori theoretical model of reading. Taken together, these subtypes account for 79% of the participants with dyslexia. Further, the percentages of children in each subtype are in good agreement with previous studies. The participants in the subtype not predicted by the double-deficit hypothesis were significantly older than the other three groups. Recent advances in unsupervised learning can be expected to aid the improvement and refinement of the definition of developmental dyslexia. If reliable and consistent subtypes can be identified among persons with developmental dyslexia, it is reasonable to assume that diagnostic and intervention efforts will be greatly improved.

Due to the fact that it is frequently difficult to identify their etiological origins, reading and writing difficulties have inconsistent terminology in the literature. This article is a review and attempts to initiate a discussion about visual dyslexia. The authors pose the question whether - in the context of new neuroimaging methods and the neurosciences broadly defined - there exist reading and writing difficulties that stem from impaired functioning of the visual system and whether they can be assigned to developmental dyslexia. If it is assumed that developmental dyslexia is linguistic in nature, these are phonological deficits that come to the fore in children entering the world of reading. These phonological processing deficits impair word decoding (word identification), making word recognition impossible, thus preventing access to higher-order linguistic processes, that is comprehending meaning from texts or building one’s own narratives.

The purpose of this study was to examine whether developmental dyslexia (DD) is characterized by deficiencies in speech sensory and motor feedforward and feedback mechanisms, which are involved in the modulation of phonological representations. A total of 42 adult native speakers of Dutch (22 adults with DD; 20 participants who were typically reading controls) were asked to produce /bep/ while the first formant (F1) of the /e/ was not altered (baseline), increased (ramp), held at maximal perturbation (hold), and not altered again (after-effect). The F1 of the produced utterance was measured for each trial and used for statistical analyses. The measured F1s produced during each phase were entered in a linear mixed-effects model. Participants with DD adapted more strongly during the ramp phase and returned to baseline to a lesser extent when feedback was back to normal (after-effect phase) when compared with the typically reading group. In this study, a faster deviation from baseline during the ramp phase, a stronger adaptation response during the hold phase, and a slower return to baseline during the after-effect phase were associated with poorer reading and phonological abilities. The data of the current study are consistent with the notion that the phonological deficit in DD is associated with a weaker sensorimotor magnet for phonological representations.

A remediation programme was devised and implemented in a case study of a developmental phonological dyslexic. Psycholinguistic assessment determined the developmental stage at which the subject's acquisition of reading skills had arrested. This was determined to be at the logographic stage of reading (Frith, 1985) so his pattern of performance resembled that of phonological dyslexics. Remediation focused on development of an alphabetic or phonological strategy for reading. The efficacy of remediation was investigated employing a single-subject case study incorporating a crossover design with multiple baseline and repeated pre- and post-therapy measures. The results of therapy indicated significant improvement in phonological reading skills as a consequence of the treatment. In addition, these effects generalised to untreated items and were accompanied by changes in reading strategy. Theoretical explanations and practical implications of the results are discussed.

H.M. is a 17-year-old girl of at least average intelligence and with an above-average oral vocabulary. She is impaired at non-word reading in comparison to word reading. She is incapable of reading any long nonsense words or long unusual regular words correctly. Many of her non-word reading responses are lexicalizations. She reads non-words homophonic with real words better than she reads non-words that are not homophonic with real words. Her reading age is 10 years 11 months. A large proportion of her reading errors are derivational or visual paralexias. She makes no semantic errors or errors of regularization and few neologistic responses. H.M. is not influenced by the dimensions of spelling-to-sound regularity and word length. There is no effect of word class on single-word reading although a function word deficit is present when continuous text is read aloud. H.M. is impaired at word reading when the stimulus items are distorted in a manner that reduces the potential for global perception. H.M.'s spelling errors are primarily phonological, though more complex errors are made than those characteristic of surface agraphics. All of these features are consistent with reported cases of acquired phonological dyslexia. H.M. may be confidently regarded as a developmental phonological dyslexic.

Recent research with English developmental dyslexics comparing the picture naming performance of these children to the picture naming performance of non-dyslexic (‘garden variety’) poor readers, reading age matched controls and chronological age matched controls has suggested that a selective difficulty in retrieving the phonological codes of known names on demand underlies the picture naming deficit found in developmental dyslexia (Swan & Goswami, Picture naming deficits in developmental dyslexia: the phonological representations hypothesis, Brain and Language, 56 (1997), 334–353). If the underlying causal factors in dyslexia are independent of the orthography that the child is learning to read, then a difficulty in retrieving the phonological codes of known names on demand should also be found in developmental dyslexics who are learning to read other languages. We therefore set out to replicate Swan and Goswami’s study with a group of German developmental dyslexics. We were interested to see whether a phonological deficit is characteristic of dyslexia in all orthographies, even those, such as German, in which high orthographic transparency means that dyslexic children read with considerable accuracy.

Extensive research has shown that phonological awareness including phoneme awareness skills are vital when children acquire literacy skills in alphabetic languages especially in English. Furthermore, research on developmental dyslexia (DD) especially in English has been conducted with research-informed/well-established definitions of DD. This is because compared to other languages, the prevalence of DD in English is high, and thus children with DD form a large minority group. These dyslexia research encompasses cognitive-behavioural, neuroimaging, behavioural and molecular-genetic studies. There seems to be a consensus amongst these researchers that DD manifests itself as a phonological deficit, and thus the phonological deficit hypothesis (as well as naming disfluency) for DD has become prominent in the alphabetic languages, especially in English. This is because print-to-sound or sound-to-print mappings in English are not always one-to-one and thus opaque/inconsistent. Now important questions arise in discussing how children acquire reading skills in non-alphabetic languages especially in Japanese where logographic Kanji and 2-forms of syllabic Kana are used: (i) are phonological awareness skills vital when children learn to read in Japanese? (ii) can the phonological deficit hypothesis explain DD in Japanese? These questions will be addressed in this paper by comparing the behavioural and some neuroimaging studies in alphabetic languages and Japanese Kanji and Kana as well as Chinese, another non-alphabetic languag. It seems that phonological awareness may not be as important for non-alphabetic languages such as Chinese or Japanese at the start of literacy acquisition. Phonological awareness become important skills in Chinese and Japanese only when children are older. Instead of phonological awareness other metalinguistic awareness skills are important for acquisition of reading in Chinese and Japanese such as orthographic or morphological awareness (Chinese), vocabulary size (Japanese), visuo-spatial processing (Chinese and Japanese) and visual-motor integration (Chinese and Japanese) skills. Also available neuroimaging studies will be used to uncover the behavioural dissociation and the neural unity in an English-Japanese bilingual adolescent boy with monolingual dyslexia in English.

To determine whether individuals with developmental dyslexia present differences in visual and oculomotor functions compared with age-matched controls. Developmental dyslexia affects a substantial proportion of school-aged children, with prevalence estimates ranging between 3% and 6%, depending on diagnostic criteria. It is characterised by persistent reading difficulties despite normal intelligence and education. Although phonological deficits are well established, the contribution of visual and oculomotor anomalies remains debated. Identifying consistent visual differences may support more comprehensive assessments and targeted interventions alongside educational strategies. This systematic review and meta-analysis, registered in PROSPERO (CRD420251119429), included observational case-control studies comparing visual and oculomotor functions in individuals with developmental dyslexia and age-matched controls. Searches were conducted in PubMed, Web of Science, and Scopus. Outcomes included binocular vision, oculomotor performance, accommodation, visual acuity, refractive error and contrast sensitivity. Methodological quality was assessed using the MINORS tool and certainty of evidence using GRADE. Twenty-six studies with 8 to 124 participants per group were included. Dyslexic individuals showed significantly greater near exophoria (mean difference 0.84 prism diopters, 95% CI: 0.22 to 1.46) and reduced near fusional vergence ranges, including negative (-6.42 prism diopters, 95% CI: -8.65 to -4.19) and positive fusional vergence (-6.72 prism diopters, 95% CI: -8.66 to -4.77), all p < 0.01. Oculomotor differences included a higher number of fixations, longer fixation duration, more regressions and reduced saccade amplitude. No significant group differences were found for refractive error or visual acuity. Children with developmental dyslexia exhibit consistent binocular and oculomotor anomalies that may increase visual effort during reading. Incorporating targeted assessment of these functions into vision care may complement multidisciplinary management. Further research is needed to clarify their clinical relevance.

Atypical phase alignment of low-frequency neural oscillations to speech rhythm has been implicated in phonological deficits in developmental dyslexia. Atypical phase alignment to rhythm could thus also characterize infants at risk for later language difficulties. Here, we investigate phase-language mechanisms in a neurotypical infant sample. 122 two-, six- and nine-month-old infants were played speech and non-speech rhythms while EEG was recorded in a longitudinal design. The phase of infants’ neural oscillations aligned consistently to the stimuli, with group-level convergence towards a common phase. Individual low-frequency phase alignment related to subsequent measures of language acquisition up to 24 months of age. Accordingly, individual differences in language acquisition are related to the phase alignment of cortical tracking of auditory and audiovisual rhythms in infancy, an automatic neural mechanism. Automatic rhythmic phase-language mechanisms could eventually serve as biomarkers, identifying at-risk infants and enabling intervention at the earliest stages of development.