Phonological Processing Deficits in a Child with Developmental Dyslexia- A Case Report

Phonological, temporal and spectral processing in vowel length discrimination is impaired in German primary school children with developmental dyslexia.

Phonological processing and arithmetic fact retrieval: Evidence from developmental dyslexia

The present study describes two French teenagers with developmental reading and writing impairments whose performance was compared to that of chronological age and read- ing age matched non-dyslexic participants. Laurent conforms to the pattern of phonological dyslexia: he exhibits a poor performance in pseudo-word reading and spelling, produces phonologically inaccurate misspellings but reads most exception words accurately. Nicolas, in contrast, is poor in reading and spelling of exception words but is quite good at pseudo- word spelling, suggesting that he suffers from surface dyslexia and dysgraphia. The two participants were submitted to an extensive battery of metaphonological tasks and to two visual attentional tasks. Laurent demonstrated poor phonemic awareness skills but good visual processing abilities, while Nicolas showed the reverse pattern with severe difficulties in the visual attentional tasks but good phonemic awareness. The present results suggest that a visual attentional disorder might be found to be associated with the pattern of developmental surface dyslexia. The present findings further show that phonological and visual processing deficits can dissociate in developmental dyslexia.

Problems with subject-verb agreement and phonological (processing) skills have been reported to occur in children with specific language impairment (SLI) and in those with developmental dyslexia, but only a few studies have compared such problems in these two groups. Previous studies have claimed a causal relationship between phonological processing deficits and morphosyntactic problems. The following questions were addressed in this study: (1) Are children with developmental dyslexia and SLI comparable in the level of sensitivity to subject-verb agreement, phonological awareness, and non-word repetition? (2) Are children with developmental dyslexia and SLI comparable in their performance profiles on tasks tapping subject-verb agreement, phonological awareness, and non-word repetition? (3) Are deficits in phonological processing skills related to morphosyntactic deficits? Forty-five children (mean age = 8;6 years) with developmental dyslexia, SLI and typically developing children participated. The sensitivity to subject-verb agreement, phonological awareness, and non-word repetition was measured. Both the children with dyslexia and with SLI made more errors than the control children on the subject-verb agreement task, with the children with dyslexia scoring significantly better than the children with SLI. Similarly, the children with SLI and dyslexia both performed more poorly on the phoneme-deletion task than the control group. Both clinical groups performed more poorly on the non-word repetition task than the control children, with the children with dyslexia outperforming the children with SLI. In all three tasks differences in performance profiles were found between the children with developmental dyslexia and SLI. Across all three groups non-word repetition was correlated with morphosyntactic sensitivity. The results show similarities between the performances of children with SLI and dyslexia on tasks tapping subject-verb agreement, phonological awareness, and non-word repetition: they scored more poorly than typically developing children. Qualitative analyses revealed, however, differences in the error patterns on all three tasks. Associations between non-word repetition and sensitivity to subject-verb agreement were found, suggesting that problems with phonological processing impact on morphosyntactic skills.

Reading in callosal agenesis

Problem statement: Developmental Dyslexia (DD) or Reading Disability (RD) that was part of a larger heterogeneous group of learning di sorders and characterized by unexpected problems in academic performance, despite average intelligence. Approach: Current opinions on the biological basis of dyslexia pointed to problems with phonolog ical processing deficits with resulting poor phonemic awareness. Though there was much support for this hypothesis in the scientific literature, there remained an ongoing debate as to whether the core deficit was in fact a more general information processing problem that involves phonological aware ness, phonological short-term memory, phonological re/de-coding (Rapid Automatized Naming, RAN). Results: Also double deficit hypothesis proposed that the dyslexic children impa ired in word-identification accuracy or exhibiting slowly word decoding profile. Conclusion/Recommendations: The aim of this review was to present some of the most exciting researches on DD in the d omains of phonological deficit theory that those will help future studies to follow.

Le cerveau lecteur : histoire naturelle et culturelle

The main diagnostic criterion for developmental dyslexia (DD) in transparent orthographies is a remarkable reading speed deficit, which is often accompanied by spelling difficulties. These deficits have been traced back to both deficits in orthographic and phonological processing. For a better understanding of the reading speed deficit in DD it is necessary to clarify which processing steps are degraded in children with DD during reading. In order to address this question the present study used EEG to investigate three reading related ERPs: the N170, N400 and LPC. Twenty-nine children without DD and 52 children with DD performed a phonological lexical decision (PLD)—task, which tapped both orthographic and phonological processing. Children were presented with words, pseudohomophones, pseudowords and false fonts and had to decide whether the presented stimulus sounded like an existing German word or not. Compared to control children, children with DD showed deficits in all the investigated ERPs. Firstly, a diminished mean area under the curve for the word material-false font contrasts in the time window of the N170 was observed, indicating a reduced degree of print sensitivity; secondly, N400 amplitudes, as suggested to reflect the access to the orthographic lexicon and grapheme-phoneme conversion, were attenuated; and lastly, phonological access as indexed by the LPC was degraded in children with DD. Processing differences dependent on the linguistic material in children without DD were observed only in the LPC, suggesting that similar reading processes were adopted independent of orthographic familiarity. The results of this study suggest that effective treatment should include both orthographic and phonological training. Furthermore, more longitudinal studies utilizing the same task and stimuli are needed to clarify how these processing steps and their time course change during reading development.

Altered brain structure in Chinese dyslexic children

Brain mechanisms in normal and dyslexic readers

There is strong converging evidence suggesting that developmental dyslexia stems from a phonological processing deficit. However, this hypothesis has been challenged by the widely admitted heterogeneity of the dyslexic population, and by several reports of dyslexic individuals with no apparent phonological deficit. In this paper, we discuss the hypothesis that a phonological deficit may not be the only core deficit in developmental dyslexia and critically examine several alternative proposals. To establish that a given cognitive deficit is causally related to dyslexia, at least two conditions need to be fulfilled. First, the hypothesized deficit needs to be associated with developmental dyslexia independently of additional phonological deficits. Second, the hypothesized deficit must predict reading ability, on both empirical and theoretical grounds. While most current hypotheses fail to fulfil these criteria, we argue that the visual attentional deficit hypothesis does. Recent studies providing evidence for the independence of phonological and visual attentional deficits in developmental dyslexia are reviewed together with empirical data showing that phonological and visual attentional processing skills contribute independently to reading performance. A theoretical model of reading is outlined in support of a causal link between a visual attentional disorder and a failure in reading acquisition.

Knowledge of oscillatory entrainment and its fundamental role in cognitive and behavioral processing has increasingly been applied to research in the field of reading and developmental dyslexia. Growing evidence indicates that oscillatory entrainment to theta frequency spoken language in the auditory domain, along with cross-frequency theta-gamma coupling, support phonological processing (i.e., cognitive encoding of linguistic knowledge gathered from speech) which is required for reading. This theory is called the temporal sampling framework (TSF) and can extend to developmental dyslexia, such that inadequate temporal sampling of speech-sounds in people with dyslexia results in poor theta oscillatory entrainment in the auditory domain, and thus a phonological processing deficit which hinders reading ability. We suggest that inadequate theta oscillations in the visual domain might account for the many magno-dorsal processing, oculomotor control and visual deficits seen in developmental dyslexia. We propose two possible models of a magno-dorsal visual correlate to the auditory TSF: (1) A direct correlate that involves “bottom-up” magnocellular oscillatory entrainment of the visual domain that occurs when magnocellular populations phase lock to theta frequency fixations during reading and (2) an inverse correlate whereby attending to text triggers “top-down” low gamma signals from higher-order visual processing areas, thereby organizing magnocellular populations to synchronize to a theta frequency to drive the temporal control of oculomotor movements and capturing of letter images at a higher frequency.

Developmental dyslexia is characterized by impaired word recognition, which is thought to result from deficits in phonological processing. Improvements during the course of development are thought to disproportionately involve orthographic components of reading; phonological deficits persist into adulthood. To localize the neural correlates of impaired word recognition and phonological processing in men with developmental dyslexia. Regional cerebral blood flow was measured with oxygen 15 positron emission tomography in 17 men with dyslexia and in 14 matched controls during the performance of phonological and orthographic tasks--pronunciation (reading aloud) and lexical decision making--designed to activate posterior and anterior perisylvian cortices, respectively. Altered patterns of activation (reduced activation, unusual deactivation) were seen in dyslexic men in mid- to posterior temporal cortex bilaterally and in inferior parietal cortex, predominantly on the left, during both pronunciation and decision making. In contrast, dyslexic men demonstrated essentially normal activation of left inferior frontal cortex during both phonological and orthographic decision making. These, along with prior findings, are compatible with a hypothesis of bilateral involvement of posterior temporal and parietal cortices in dyslexia.

Developmental dyslexia (DD) has been related to deficits in multiple cognitive skills. Phonological processing deficits are the most frequently reported in opaque orthographies, but there are few studies of transparent orthographies, such as Spanish. The aim of this study was to comprehensively explore possible deficiencies in cognitive functions in Spanish-speaking Mexican children with DD, to determine whether these deficits can explain problems with decoding fluency and accuracy, and analyze whether they provide support for some of the explanatory hypotheses of DD. An extensive cognitive assessment was performed with Spanish-speaking readers: 40 children (20 girls) with DD (mean age 9.02 years, SD = 1.49) and 40 children (20 girls) who were typical readers (mean age 9.22 years, SD = 1.45). Our results showed that most of the children with DD presented deficits in multiple cognitive skills, although not all of these skills contributed to reading performance. These cognitive deficits were not equally distributed among all children and there was no cognitive skill in which all participants with DD showed poor performance. Our results demonstrated that recognition of letter orientation, phonological awareness, and rapid automatized naming were significant predictors of reading ability. These findings support the idea that reading is a multifactorial process involving many cognitive skills, and its disruption could arise from different causes. The main findings are discussed in relation to the major explanatory hypotheses of DD. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

The double-deficit hypothesis (Wolf, M. and Bowers, P.G. (1999) The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91, 415-438) proposes that deficits in phonological processing and rapid automatized naming (RAN) are separable sources of reading dysfunction. Further, the double-deficit hypothesis predicts that the presence of deficits in both phonological processing and RAN have an additive negative influence on reading performance above and beyond that of a single deficit. The purpose of this study was to examine the additive nature of phonological awareness (PA)- and RAN-deficits on written language skill in children with reading disabilities (RD). Concurrent relationships between PA, RAN, and written language skills were examined in 476 children with RD, ranging in age from 8 to 18 years of age. Hierarchical regression analysis revealed that PA and RAN skill have an additive effect on a majority of the reading and spelling measures. When participants were classified into three deficit subtypes based on the double-deficit model (i.e. phonological-, rate-, and double-deficit), comparisons across the subtypes confirmed that individuals with double-deficits performed below the single-deficit groups on both subtyping variables (RAN and PA) and all measures of written language. When the double- and single-deficit groups were matched on the subtyping variable (i.e. double- and rate-deficit groups matched on RAN and double- and phonological-deficit groups matched on PA) differences between the double- and rate-deficit groups remained in non-word reading, whereas differences between the double- and phonological-deficit groups remained in timed word recognition and reading comprehension. These results support an additive model in which RAN-deficits primarily affect tasks that require speeded/fluent response, and PA-deficits primarily affect tasks that emphasize phonological processing skill. Results are also presented that illustrate several statistical problems associated with the formation of deficit groups by dichotomizing the RAN and PA variables.