Blog Archives

Orthographic processing and reading comprehension among Arabic speaking mainstream and LD children

Two cohorts of mainstream children (grades 2–5) and one cohort of children with learning disabilities (LD; grades 3–5), all Arabic speaking children in Kuwait, were given measures of reading comprehension fluency and orthographic discrimination to assess the relationship between the two. Additional measures of phonological processing (decoding and awareness), speed of processing (rapid naming) and memory (visual as well as phonological/verbal tasks) were included either because these have been found to be predictive of Arabic literacy or to provide an assessment of alternative interpretations of any influence of the orthographic task. The findings indicated that the orthographic measure predicted variability in the comprehension fluency over-and-above that predicted by the other measures in the study. This was significant in the older mainstream children (grades 4 and 5) when controlling for phonological processing, but was not in the younger grades (2 and 3) where experience text that incorporating short vowel markers is dominant. The LD group showed little evidence of an influence of phonological processing but did of orthographic processing. The findings are discussed in terms of the skills required to process Arabic literacy and potential causes of literacy learning difficulties among Arabic children. Copyright © 2011 John Wiley & Sons, Ltd.

from Dyslexia

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Neural correlates of phonological processing in speech sound disorder: A functional magnetic resonance imaging study

Speech sound disorders (SSD) are the largest group of communication disorders observed in children. One explanation for these disorders is that children with SSD fail to form stable phonological representations when acquiring the speech sound system of their language due to poor phonological memory (PM). The goal of this study was to examine PM in individuals with histories of SSD employing functional MR imaging (fMRI). Participants were six right-handed adolescents with a history of early childhood SSD and seven right-handed matched controls with no history of speech and language disorders. We performed an fMRI study using an overt non-word repetition (NWR). Right lateralized hypoactivation in the inferior frontal gyrus and middle temporal gyrus was observed. The former suggests a deficit in the phonological processing loop supporting PM, while the later may indicate a deficit in speech perception. Both are cognitive processes involved in speech production. Bilateral hyperactivation observed in the pre and supplementary motor cortex, inferior parietal, supramarginal gyrus and cerebellum raised the possibility of compensatory increases in cognitive effort or reliance on the other components of the articulatory rehearsal network and phonologic store. These findings may be interpreted to support the hypothesis that individuals with SSD may have a deficit in PM and to suggest the involvement of compensatory mechanisms to counteract dysfunction of the normal network.

from Brain and Language

Response Inhibition and its Relationship to Phonological Processing in Children with and without Dyslexia

This study investigates response inhibition and its relationship to phonological processing in third-graders with and without dyslexia. Children with dyslexia (n = 20) and children without dyslexia (n = 16) were administered a stop signal task and a digit span forwards task. Initial analyses revealed phonological processing deficits in terms of a phonological short-term deficit in children with dyslexia but revealed no group differences with regard to performance on the stop signal task. There was no relationship between performance on the stop signal task and phonological short-term capacity for the group of children with dyslexia. In contrast, in the group of children without dyslexia, there was a tendency that better phonological short-term capacity was associated with faster primary reaction times on the stop signal task. Furthermore, better phonological short-term capacity was related to slower inhibitory processes among children without dyslexia. When controlling group—specifically for the effects of phonological short-term capacity on the performance on the stop signal task—we found slightly faster primary reaction times and significantly slower inhibitory processes in the group of children with dyslexia. Overall, these findings suggest the activation of phonological strategies during performance on the stop signal task in children without dyslexia but not in children with dyslexia. We discuss the possibility that in children without dyslexia, phonological processing strategies might have a beneficial effect on speed of response execution but might slow down response inhibition.

from the International Journal of Disability, Development and Education

An event-related potential investigation of lexical pitch-accent processing in auditory Japanese

Lexical prosody plays an important role in speech comprehension. However, the electrophysiological nature and time course of processing lexical prosody in mora-timed languages are rarely known in contrast to the wealth of knowledge in stress-timed languages and syllable-timed languages like German and French. In the present study, lexical pitch-accent processing in Japanese is investigated using event-related potentials. Participants listened to sentences with verbs either correct or incorrect with respect to pitch-accent (phonological condition), word meaning (semantic condition) or sentence type (syntactic condition). When the brain potentials of correct and incorrect sentences were compared within conditions, the phonological and semantic conditions showed a negativity and positivity (P600), while the syntactic condition displayed a P600. Furthermore, the negativity in response to pitch-accent violations (pitch-accent negativity) appeared approximately 60 ms earlier than the response to semantic violations (N400), while no significant topographical distributions were found between the two components. These results suggest that the pitch-accent negativity reflects initial phonological processing followed by lexical access and word recognition. Moreover, the P600 displayed in all conditions was interpreted as a general integration process that is common across the three domains.

from Brain Research

Lexicality and Frequency in Specific Language Impairment: Accuracy and Error Data from Two Nonword Repetition Tests

Conclusions: The data show support for a phonological processing deficit in children with SLI, where long-term lexical and sublexical phonological knowledge mediate the interpretation of nonwords. However, the data also suggest that while phonological processing may provide a key explanation of SLI, a full account is likely to be multifaceted.

from the Journal of Speech, Language, and Hearing Research

Dutch children at family risk of dyslexia: precursors, reading development, and parental effects

The study concerns reading development and its precursors in a transparent orthography. Dutch children differing in family risk for dyslexia were followed from kindergarten through fifth grade. In fifth grade, at-risk dyslexic (n = 22), at-risk non-dyslexic (n = 45), and control children (n = 12) were distinguished. In kindergarten, the at-risk non-dyslexics performed better than the at-risk dyslexics, but worse than the controls on letter-knowledge and rapid naming. The groups did not differ on phonological awareness. At-risk dyslexics read less fluently from first grade onwards than the other groups. At-risk non-dyslexics’ reading fluency was at an intermediate position between the other groups at the start of reading. By fifth grade they had reached a similar level as the controls on word reading, but still lagged behind on pseudoword reading. Results further showed that the parents of the groups of at-risk children differed in educational level and reading skills. Overall, the groups of at-risk children differed on pre-reading skills as well as on reading development. These differences do not seem to stem from differences in intellectual abilities or literacy environment. Instead, the better reading skills of parents of at-risk non-dyslexics suggest that these children might have a lower genetic liability.

from Dyslexia

Early Oral Language Markers of Poor Reading Performance in Hong Kong Chinese Children

This study investigated the extent to which language skills at ages 2 to 4 years could discriminate Hong Kong Chinese poor from adequate readers at age 7. Selected were 41 poor readers (age M = 87.6 months) and 41 adequate readers (age M = 88.3 months). The two groups were matched on age, parents’ education levels, and nonverbal intelligence. The following language tasks were tested at different ages: vocabulary checklist and Cantonese articulation test at age 2; nonword repetition, Cantonese articulation, and receptive grammar at age 3; and nonword repetition, receptive grammar, sentence imitation, and story comprehension at age 4. Significant differences between the poor and adequate readers were found in the age 2 vocabulary knowledge, age 3 Cantonese articulation, and age 4 receptive grammar skill, sentence imitation, and story comprehension. Among these measures, sentence imitation showed the greatest power in discriminating poor and adequate readers.

from the Journal of Learning Disabilities

The nature of the phonological processing in French dyslexic children: evidence for the phonological syllable and linguistic features’ role in silent reading and speech discrimination

This study investigated the status of phonological representations in French dyslexic children (DY) compared with reading level- (RL) and chronological age-matched (CA) controls. We focused on the syllable’s role and on the impact of French linguistic features. In Experiment 1, we assessed oral discrimination abilities of pairs of syllables that varied as a function of voicing, mode or place of articulation, or syllable structure. Results suggest that DY children underperform controls with a ‘speed-accuracy’ deficit. However, DY children exhibit some similar processing than those highlighted in controls. As in CA and RL controls, DY children have difficulties in processing two sounds that only differ in voicing, and preferentially process obstruent rather than fricative sounds, and more efficiently process CV than CCV syllables. In Experiment 2, we used a modified version of the Colé, Magnan, and Grainger’s (Applied Psycholinguistics 20:507–532, 1999) paradigm. Results show that DY children underperform CA controls but outperform RL controls. However, as in CA and RL controls, data reveal that DY children are able to use phonological procedures influenced by initial syllable frequency. Thus, DY children process syllabically high-frequency syllables but phonemically process low-frequency syllables. They also exhibit lexical and syllable frequency effects. Consequently, results provide evidence that DY children performances can be accounted for by laborious phonological syllable-based procedures and also degraded phonological representations.

from the Annals of Dyslexia

The EpiSLI Database: A Publicly Available Database on Speech and Language

Clinical Implications: If our research questions are concerned with the characteristics of the actual population of children with SLI that exists in our communities and not just those who are being served, then we need to turn to methods of epidemiology to aid our research.

from Language, Speech and Hearing Services in Schools

DIFFERENT UNDERLYING NEUROCOGNITIVE DEFICITS IN DEVELOPMENTAL DYSLEXIA: A COMPARATIVE STUDY

The aim of this study was to investigate the role of several specific neurocognitive functions in developmental dyslexia (DD). The performances of 60 dyslexic children and 65 age-matched normally reading children were compared on tests of phonological abilities, visual processing, selective and sustained attention, implicit learning, and executive functions. Results documented deficits in dyslexics on both phonological and non-phonological tasks. More stringently, in dyslexic children individual differences in non-phonological abilities accounted for 23.3% of unique variance in word reading and for 19.3% in non-word reading after controlling for age, IQ and phonological skills. These findings are in accordance with the hypothesis that DD is a multifactorial deficit and suggest that neurocognitive developmental dysfunctions in DD may not be limited to the linguistic brain area, but may involve a more multifocal cortical system.

from Neuropsychologia

DIFFERENT UNDERLYING NEUROCOGNITIVE DEFICITS IN DEVELOPMENTAL DYSLEXIA: A COMPARATIVE STUDY

The aim of this study was to investigate the role of several specific neurocognitive functions in developmental dyslexia (DD). The performances of 60 dyslexic children and 65 age-matched normally reading children were compared on tests of phonological abilities, visual processing, selective and sustained attention, implicit learning, and executive functions. Results documented deficits in dyslexics on both phonological and non-phonological tasks. More stringently, in dyslexic children individual differences in non-phonological abilities accounted for 23.3% of unique variance in word reading and for 19.3% in non-word reading after controlling for age, IQ and phonological skills. These findings are in accordance with the hypothesis that DD is a multifactorial deficit and suggest that neurocognitive developmental dysfunctions in DD may not be limited to the linguistic brain area, but may involve a more multifocal cortical system.

from Neuropsychologia

Reading and Subcortical Auditory Function

Although it is largely agreed that phonological processing deficits are a major cause of poor reading, the neural origins of phonological processing are not well understood. We now show, for the first time, that phonological decoding, measured with a test of single-nonword reading, is significantly correlated with the timing of subcortical auditory processing and also, to a lesser extent, with the robustness of subcortical representation of the harmonic content of speech, but not with pitch encoding. The relationships we observe between reading and subcortical processing fall along a continuum, with poor readers at one end and good readers at the other. These data suggest that reading skill may depend on the integrity of subcortical auditory mechanisms and are consistent with the idea that subcortical representation of the acoustic features of speech may play a role in normal reading as well as in the development of reading disorders. These data establish a significant link between subcortical auditory function and reading, thereby contributing to the understanding of the biological bases of reading. At a more general level, these findings are among the first to establish a direct relationship between subcortical sensory function and a specific cognitive skill (reading). We argue that this relationship between cortical and subcortical function could be shaped during development by the corticofugal pathway and that this cortical–subcortical link could contribute to the phonological processing deficits experienced by poor readers.

from Cerebral Cortex

Unintended imitation in nonword repetition

Verbal repetition is conventionally considered to require motor-reproduction of only the phonologically relevant content of a perceived linguistic stimulus, while imitation of incidental acoustic properties of the stimulus is not an explicit part of this task. Exemplar-based theories of speech processing, however, would predict that imitation beyond linguistic reproduction may occur in word repetition. Five experiments were conducted in which verbal audio-motor translations had to be performed under different conditions. Nonwords varying in phonemic content, in vocal pitch (F0), and in speaking style (schwa-syllable expression) were presented. We experimentally varied the factors response delay (repetition vs. shadowing), intention-to-repeat (repetition vs. pseudo-naming), and phonological load (repetition vs. transformation). The responses of ten healthy participants were examined for phonemic accuracy and for traces of para-phonological imitation. Two aphasic patients with phonological impairments were also included, to find out if lesions to left anterior or posterior perisylvian cortex interfere with imitation.

In the healthy participants, significant imitation of both F0 and phonetic style was observed, with markedly stronger effects for the latter. Strong imitation was also found in an aphasic patient with a lesion to left anterior perisylvian cortex, whereas almost no imitation occurred in a patient with a lesion to the posterior language area. The degree of unintended imitation was modulated by each of the three independent factors introduced here. The results are discussed on the background of cognitive and neurolinguistic theories of imitation.

from the Journal of Voice

From Phonemes to Articulatory Codes: An fMRI Study of the Role of Broca’s Area in Speech Production

We used event-related functional magnetic resonance imaging to investigate the neuroanatomical substrates of phonetic encoding and the generation of articulatory codes from phonological representations. Our focus was on the role of the left inferior frontal gyrus (LIFG) and in particular whether the LIFG plays a role in sublexical phonological processing such as syllabification or whether it is directly involved in phonetic encoding and the generation of articulatory codes. To answer this question, we contrasted the brain activation patterns elicited by pseudowords with high– or low–sublexical frequency components, which we expected would reveal areas related to the generation of articulatory codes but not areas related to phonological encoding. We found significant activation of a premotor network consisting of the dorsal precentral gyrus, the inferior frontal gyrus bilaterally, and the supplementary motor area for low– versus high–sublexical frequency pseudowords. Based on our hypothesis, we concluded that these areas and in particular the LIFG are involved in phonetic and not phonological encoding. We further discuss our findings with respect to the mechanisms of phonetic encoding and provide evidence in support of a functional segregation of the posterior part of Broca’s area, the pars opercularis.
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from Cerebral Cortex

Pseudohomophone effects in processing Chinese compound words

The issue of how phonological information becomes available in reading Chinese and the role that it plays in lexical access was investigated for Chinese compound words, using pseudohomophone effects in lexical and phonological decision as a diagnostic tool. Pseudohomophones were created by replacing one or both constituents of two-character compound words with orthographically dissimilar homophonic characters. Experiment 1 found that mixed pseudohomophones sharing one constituent with their base words were more difficult to reject than control nonwords in lexical decision. Pure pseudohomophones sharing no constituents with their base words did not show this effect. Experiment 2 used mixed pseudohomophones and found an interaction between base word frequency and the frequency of constituent characters in determining pseudohomophone effects. Experiment 3 used a phonological decision task and found exceptionally poor performance for pure pseudohomophones. These results are interpreted in an interactive framework where the direct mapping from orthography to semantics is dominant and phonology plays a subsidiary role.

from Language and Cognitive Processes