Is There a Dissociation Between Deficit Subtypes in Word Reading and/or Spelling? A Longitudinal Study From Grade 1 to Grade 4 Across Orthographies.

There is an ongoing debate concerning the extent to which deficits in reading and spelling share cognitive components and whether they rely, in a similar fashion, on sublexical and lexical pathways of word processing. The present study investigates whether the neural substrates of word processing differ in children with various patterns of reading and spelling deficits. Using functional magnetic resonance imaging, we compared written and auditory processing in three groups of 9–13-year olds (N = 104): (1) with age-adequate reading and spelling skills; (2) with reading and spelling deficits (i.e., dyslexia); (3) with isolated spelling deficits but without reading deficits. In visual word processing, both deficit groups showed hypoactivations in the posterior superior temporal cortex compared to typical readers and spellers. Only children with dyslexia exhibited hypoactivations in the ventral occipito-temporal cortex compared to the two groups of typical readers. This is the result of an atypical pattern of higher activity in the occipito-temporal cortex for non-linguistic visual stimuli than for words, indicating lower selectivity. The print–speech convergence was reduced in the two deficit groups. Impairments in lexico-orthographic regions in a reading-based task were associated primarily with reading deficits, whereas alterations in the sublexical word processing route could be considered common for both reading and spelling deficits. These findings highlight the partly distinct alterations of the language network related to reading and spelling deficits.

Pleiotropic Effects of a Chromosome 3 Locus on Speech-Sound Disorder and Reading

Findings on the neurophysiological correlates of developmental dyslexia are mixed, due to the differential conceptualization of the impairment. Studies differ on whether participants with developmental dyslexia are recruited based on reading skills only or reading as well as spelling skills. The current study contrasts the contribution of impaired reading and spelling to ERP correlates of print sensitivity, lexico-semantic access and sensitivity to orthographic regularities. Four groups of children were recruited: isolated reading deficit, isolated spelling deficit, combined reading and spelling deficit, and typically developing. Their neural correlates (EEG) of word, pseudohomophone, and pseudoword reading, as well as false font processing were compared. 1) All groups showed higher N1 amplitudes to letters than to false fonts. 2) Good spellers exhibited more negative N400 amplitudes for meaningless (pseudowords) than for meaningful stimuli (words and pseudohomophones). This effect was not observed in poor spellers. 3) Good readers showed sensitivity to orthographic regularities in a later time window (700–900 ms), whereas this was not the case for poor readers. 1) Print sensitivity is not affected by reading and/or spelling deficit in German-speaking 3rd graders. 2) Spelling deficits are associated with a reduced orthographic lexicon, 3) Reading deficits are associated with atypical use of sublexical information. As this effect was observed after lexico-semantic access, the results are discussed in terms of a possible orthographic reanalysis hypothesis.

An individual diagnosed with dyslexia in childhood typically remains dyslexic throughout his/her life. However, the cognitive profile of adults with dyslexia has been less explored than that of children. This meta-analytic study is intended to clarify three questions: (1) To what extent, and in what manner, do adults with reading difficulties (dyslexia) differ from typical adult readers in measures of reading and writing competence and related cognitive skills?; (2) To what extent do speed measures pose a greater challenge than accuracy measures in an adult population that has already had years of print exposure?; and (3) To what extent does orthographic transparency modulate the reading profile of adults with dyslexia? A total of 178 studies comparing adults with dyslexia and matched controls were reviewed. The results showed that adults with dyslexia exhibited poor performance on almost all reading and writing tasks expressed by very large effect sizes (range 1.735≤ d ≤2.034), except for reading comprehension (d = 0.729). Deficits in reading- and writing-related variables are also present but with a lower expression (range 0.591≤ d ≤1.295). These difficulties are exacerbated for speed measures, especially for word and pseudoword reading, phonological awareness and orthographic knowledge. Orthographic transparency proved to be a significant moderator of dyslexic deficits in word and pseudoword reading, reading comprehension, spelling and phonological awareness, with the expression of the deficits being weaker on transparent-as opposed to intermediate and opaque-orthographies. Overall, the meta-analysis shows that reading and writing difficulties persist in adulthood and are more pronounced in speed measures. Moreover, symptoms are more severe for reading and writing than they are for measures tapping into the cognitive processes underlying reading skills. Orthographic transparency has a significant effect on the manifestation of dyslexia, with dyslexia symptoms being less marked on transparent orthographies. In addition, phonological awareness seems to be a minor problem in adulthood, especially for transparent orthographies.

Efficient and automatic integration of letters and speech sounds is assumed to enable fluent word recognition and may in turn also underlie the build-up of high-quality orthographic representations, which are relevant for accurate spelling. While previous research showed that developmental dyslexia is associated with deficient letter-speech sound integration, these studies did not differentiate between subcomponents of literacy skills. In order to investigate whether deficient letter-speech sound integration is associated with deficits in reading and/or spelling, three groups of third graders were recruited: (1) children with combined deficits in reading and spelling (RSD, N = 10); (2) children with isolated spelling deficit (ISD, N = 17); and (3) typically developing children (TD, N = 21). We assessed the neural correlates (EEG) of letter-speech sound integration using a Stroop-like interference paradigm: participants had to decide whether two visually presented letters look identical. In case of non-identical letter pairs, conflict items were the same letter in lower and upper case (e.g., “T t”), while non-conflict items were different letters (e.g., “T k”). In terms of behavioral results, each of the three groups exhibited a comparable amount of conflict-related reaction time (RT) increase, which may be a sign for no general inhibitory deficits. Event-related potentials (ERPs), on the other hand, revealed group-based differences: the amplitudes of the centro-parietal conflict slow potential (cSP) were increased for conflicting items in typical readers as well as the ISD group. Preliminary results suggest that this effect was missing for children with RSD. The results suggest that deficits in automatized letter-speech sound associations are associated with reading deficit, but no impairment was observed in spelling deficit.

total IQ, since individuals differ in their pattern of abilities on verbal/performance IQ measures; c) distortions arising from the varying criteria for dyslexia which alter the composition of the subject population used by various researchers; 2) failure to base research on an explicit theoretical model of the reading process-a shortcoming which has led to an emphasis on psycho-physical functions having no demonstrable causal relationship to reading/ spelling difficulties; and 3) inadequacies in the concept of dyslexia. Two approaches to assess reading disabilities are presented: the process-oriented and the subskill approach. Recommendations for future research are intended to avoid the above problems and include: 1) Since group comparisons do not uncover evidence about the different types of reading and spelling failures, a combination of descriptive and experimental approaches seems to be appropriate; 2) the research should be based on an explicit theoretical model of the reading process, with identification of individual subskills and their interactive connections; 3) the problem of test validity and the significance of the data should be more closely examined; and 4) small studies with limited evidence should be replaced by interdisciplinary projects. *This article has been extended and updated from Ursachen der Legasthenie: Fakten oder Artefakte? Zeitschriftfuer Paedagogik, Vol. 21, 1975, No. 3, pp. 407-418. The author is grateful to Janet Binkley for translating the original manuscript. The German term Legasthenie, referring to reading and spelling difficulties in children with normal intelligence, has been translated as dyslexia and specific reading disability, keeping in mind that dyslexia might be used with different connotations by some authors.

ABSTRACTDissociations between reading and spelling problems are likely to be associated with different underlying cognitive deficits, and with different deficits in orthographic learning. In order to understand these differences, the current study examined orthographic learning using a printed-word learning paradigm. Children (4th grade) with isolated reading, isolated spelling and combined reading and spelling problems were compared to children with age appropriate reading and spelling skills on their performance during learning novel words and symbols (non-verbal control condition), and during immediate and delayed reading and spelling recall tasks. No group differences occurred in the non-verbal control condition. In the verbal condition, initial learning was intact in all groups, but differences occurred during recall tasks. Children with reading fluency deficits showed slower reading times, while children with spelling deficits were less accurate, both in reading and spelling recall. Children with isolated spelling problems showed no difficulties in immediate spelling recall, but had problems in remembering the spellings 2 hours later. The results suggest that different orthographic learning deficits underlie reading fluency and spelling problems: Children with isolated reading fluency deficits have no difficulties in building-up orthographic representations, but access to these representations is slowed down while children with isolated spelling deficits have problems in storing precise orthographic representations in long-term memory.

The types of reading difficulties experienced by children are highly heterogeneous in nature, which makes diagnosis and intervention difficult. Over the past 30 years, there has been much debate over the cause of dyslexia. The two most popular theories for phonological deficits in dyslexia are the rate-processing constraint hypothesis, which relates to short timescale processing, and the temporal sampling framework hypothesis, which relates to longer timescale processing. To investigate the relationship between sublexical (i.e., nonword) reading skills and auditory spectral and temporal resolution patterns in children with reading difficulties using the Phoneme Identification Test (PIT) and the Parsing Syllable Envelopes Test (ParSE). These tests were developed to assess the rate-processing constraint and the temporal sampling framework hypotheses, respectively. We hypothesized that a proportion of children who have sublexical reading difficulties may have an underlying auditory-resolution deficit which may impact their ability to form letter-sound correspondences. We predicted that children's sublexical reading difficulties may not be explained by one theory, but instead that both theories may describe different types of reading difficulties found in different children. We also hypothesized that children with lexical (i.e., irregular word) reading difficulties but intact sublexical reading skills would not show atypical results on PIT or ParSE. Behavioral experimental clinical study with children who have reading difficulties. Sixteen children with nonword, irregular word, or mixed reading difficulties diagnosed by the Castles and Coltheart Test 2. Children completed a test battery consisting of a hearing screen and tests of reading, auditory resolution, phonological awareness, attention, spatial auditory processing, auditory memory, and intelligence. Categorization and correlational analyses were conducted. All four children with a pure sublexical reading deficit also had an auditory-resolution deficit. Four of seven children with a mixed reading deficit had an auditory-resolution deficit. Only one of five children with a lexical reading deficit had an auditory-resolution deficit. Individual children's specific deficits were related to either rate processing (n = 5) or temporal sampling (n = 4), but never both. Children's nonword reading scores were strongly correlated with their performance on the PIT in noise, but not with the PIT in quiet or the ParSE. Children's irregular word scores were not significantly correlated with their performance on the PIT in quiet or in noise, or the ParSE, as hypothesized. Strong correlations were also found between children's nonword scores and their phonological awareness scores. The results of this study suggest that neither the rate-processing hypothesis nor the temporal sampling framework is the single cause of reading difficulties in children. Instead, both of these hypotheses are likely to account for different types of reading deficits found in children. This is an important finding as the specific mechanisms driving different reading impairments must be identified to create tools to better diagnose and treat different types of reading difficulties. Further investigation of the PIT and ParSE as potential diagnostic tools for specific auditory-resolution-based reading difficulties in a larger group of children is currently underway.

Orthographic transparency is increasingly being recognised as an important factor in determining the manifestation of dyslexic tendencies in individuals. Recent evidence has shown that normal English-speaking children have reading deficits in the range associated with same age dyslexic German-speaking children for less frequently used words, and English orthography has been identified as a contributing factor. Spencer (Reading (1999) 33(2), 72-77; Journal of Research in Reading (1999) 22(3), 283-292) has proposed a predictive model for English children's reading and spelling deficits, based on orthographic features. Two main factors have been identified: consistency of sound representation and inclusion of redundant letters in English words. Using new data for reading, a unified model will be discussed which incorporates measures of depth of orthographic transparency and relates these to recent positron emission tomography (PET) research. Implications for the relative frequency and severity of dyslexia in both deep and shallow orthographies is considered in the light of such studies.

Dyslexia is a lifelong neurodevelopmental disorder characterized by persistent difficulties in word reading, reading fluency, and spelling despite adequate intellectual abilities and educational opportunities. This case study examines the cognitive and academic profile of CP, a high-achieving 21-year-old university student with a well-documented history of dyslexia, as she prepares for the Medical College Admission Test (MCAT; Association of American Medical Colleges, 2017). CP has experienced persistent deficits in word reading, reading fluency, and spelling, which have necessitated individualized accommodations throughout her academic career. Despite years of intensive, evidence-based reading intervention, CP continues to struggle with decoding and spelling, impacting her reading efficiency and written expression. A comprehensive psychoeducational evaluation, including the WJ V (McGrew et al., 2025) and other tests, confirmed significant ongoing weaknesses in basic reading skills, reading fluency, and spelling, consistent with a diagnosis of dyslexia. Her case underscores the importance of ongoing academic accommodations, such as extended time on tests and access to assistive technologies, to ensure that individuals with dyslexia are able to fully demonstrate their knowledge and abilities in competitive academic and professional environments.

In two studies dissociations between reading and spelling skills were examined. Study 1 reports equally high prevalence rates for isolated deficits in reading (7%) or spelling (6%) in a representative sample (N = 2,029) of German-speaking elementary school children. In Study 2, children with isolated deficits were presented with the same words to read and spell. The double dissociation was replicated. Good readers/poor spellers named pseudohomophones as quickly as their corresponding words, and their phonological awareness skills were adequate, suggesting that their reading might be based on highly efficient decoding procedures. Poor readers/good spellers showed slow word naming and a clear slowing when reading pseudohomophones suggesting a reliance on intact orthographic representations in word reading. A deficit in rapid automatized naming in this group suggests problems in fast visual–verbal access. The profile of poor readers/poor spellers fits the double-deficit group in Wolf and Bowers's (1999) dyslexia theory.

Italian children with surface dyslexia and dysgraphia show defective orthographic lexical processing in both reading and spelling. It is unclear whether this parallelism is due to impairment of separate orthographic input and output lexicons or to a unique defective lexicon. The main aim of the present study was to compare the single- versus dual-lexicon accounts in dyslexic/dysgraphic children (and in normal but younger children). In the first experiment, 9 Italian children with surface dyslexia and dysgraphia judged the orthographic correctness (input lexicon) of their phonologically plausible misspellings (output lexicon) and of phonologically plausible spellings experimentally introduced for words they consistently spelt correctly. The children were generally impaired in recognizing phonologically plausible misspellings. Parallel deficits in reading and spelling also emerged: Children were more impaired in judging items they consistently misspelt and more accurate in judging items they always spelt correctly. In a second experiment, younger normal children with reading/spelling ability similar to that of the dyslexic/dysgraphic children in the first experiment (but younger) were examined. The results confirmed a close parallelism between the orthographic lexical representations used for reading and spelling. Overall, findings support the hypothesis that a single orthographic lexicon is responsible for reading and spelling performance in both dyslexic/dysgraphic and normal (but younger) children.

Separate mechanisms for number reading and word reading: Evidence from selective impairments

ABSTRACTDeficits in reading fluency and in spelling can dissociate during development, resulting in groups with reading deficit only (RD), spelling deficit only (SD) and combined reading and spelling deficit (RSD). The current study investigated the one-to-two-year longitudinal stability of these subgroups in 167 German-speaking children. Reading fluency deficits (irrespective of spelling skills) were stable over time, while spelling deficits were stable in the RSD-group but not in the SD-group. Lower stability in the SD-group resulted from the fact that many children improved their spelling skills over time. Improvement in spelling was associated with good performance in phoneme awareness together with intact RAN and decoding skills.

Learning to read is a middle-distance race for children worldwide. Most of them succeed in this acquisition with "normal" difficulties that ensue from the progressive (re)structuring of the phonological and orthographic systems. Evidence accumulated on reading difficulties in children with developmental dyslexia (DYS children, henceforth) shows a pervasive phonological deficit. However, the phonological deficit may not be due to degraded phonological representations but rather due to impaired access to them. This study focused on how and to what extent phonological syllables, which are essential reading units in French, were accessible to DYS children to segment and access words. We tested the assumption that DYS children did not strictly have pervasive degraded phonological representations but also have impaired access to phonological and orthographic representations. We administered a visually adapted word-spotting paradigm, engaging both sublexical processing and lexical access, with French native-speaking DYS children (N = 25; Mage in months = 121.6, SD = 3.0) compared with chronological age-matched peers (N = 25; Mage in months = 121.8, SD = 2.7; CA peers henceforth) and reading level-matched peers (N = 25; Mage in months = 94.0, SD = 4.6; RL peers henceforth). Although DYS children were slower and less accurate than CA and RL peers, we found that they used phonological syllables to access and segment words. However, they exhibit neither the classical inhibitory syllable frequency effect nor the lexical frequency effect, which is generally observed in typically developing children. Surprisingly, DYS children did not show strictly degraded phonological representations because they demonstrated phonological syllable-based segmentation abilities, particularly with high-frequency syllables. Their difficulties are rather interpreted in terms of impaired access to orthographic and phonological representations, which could be a direct effect of difficulties in generalizing and consolidating low-frequency syllables. We discuss these results regarding reading acquisition and the specificities of the French linguistic system.