Rapid auditory processing and phonological ability in normal readers and readers with dyslexia

Strong Relationship Between Rapid Auditory Processing and Affective Prosody Recognition Among Adults with High Autistic Traits

This study investigated whether individuals with high autistic traits rely on psychoacoustic abilities in affective prosody recognition (APR). In 94 college students, Autism Spectrum Quotient (AQ) and psychoacoustic abilities were measured. Results indicated that higher AQ, higher rapid auditory processing (RAP), and maleness were associated with a lower APR accuracy for low-intensity prosodies. There was a strong positive association between RAP and APR for participants with high AQ, whereas low-AQ participants showed no such pattern. The findings suggest a reliance on psychoacoustic abilities as compensatory mechanism for deficits in higher-order processing of emotional signals in social interactions, and imply potential benefits of auditory interventions in improving APR among individuals with high autistic traits.

Awareness of developmental language disorder amongst workplace managers

BACKGROUND

Developmental Language Disorder (DLD) is one of the most prevalent developmental disorders and affects expressive and receptive language with no clear cause (Bishop et al., 2017). Awareness of DLD is currently much lower than other (sometimes less prevalent) disorders such as Autism or Attention Deficit Hyperactivity Disorder (ADHD) (Bishop, 2010). Despite this, it has now been established that the implications of DLD reach well into adulthood (Botting, 2020; Botting et al., 2016; Clegg et al., 2005; Johnson et al., 2010). Thus, DLD may affect not only school progress but also employment. Whilst recent research indicates that the rate of employment in this group was similar to peers (Conti-Ramsden et al., 2018), it also reported lower levels of employment in terms of hours, contracts and employment type. However, there is virtually no research examining why this might be the case. In contrast there is already a growing evidence base surrounding Autism Spectrum Disorder (ASD) and Dyslexia in the workplace. Systematic reviews of factors affecting employment in ASD and Dyslexia (de Beer et al., 2014; Scott et al., 2019) have revealed barriers including the job application process itself.

AIMS & METHODS

In this study we aimed to explore managers' awareness of DLD and their views on training, adjustments and feasibility when considering employing an individual with DLD. Specifically, we asked: 1) What awareness do managers have of DLD and how does this compare to awareness of ASD and other developmental disorders? 2) What is the extent of training on DLD and other developmental disorders in the workplace? 3) What barriers to employment are perceived to be most significant by managers? 4) What strategies do managers report as currently in place to help support people with DLD? 5) What are perceived strengths of people with DLD according to managers?

RESULTS

In total, 77 managers completed an anonymous online survey which was accessed via a social media link. Managers came from a wide variety of backgrounds with an equal split between public and private organisations, and across gender. The number of managers who had heard of DLD was lower than for the other disorders (ADHD, ASD, Dyslexia). This pattern was partly mirrored in the proportion of managers who felt they had received adequate training on communication difficulties. However, training on developmental disorders generally was reported as very scarce. A qualitative examination of barriers identified by managers included interviewing and CV submission, reading and following instructions, lack of clear guidelines around support needed, and financial restrictions in providing support.

CONCLUSIONS

These findings support existing literature and have implications for policy and practice - namely that young people with DLD may need to be proactive about disclosing their language needs, and that workplaces need increased basic training in DLD.

Factors that influence non-word repetition performance in children with and without persistent speech sound disorders

BACKGROUND

Nonword repetition (NWR) is a common phonological processing task that is reported to tap into many cognitive, perceptual, and motor processes. For this reason, NWR is often used in assessment batteries to aid in verifying the presence of a reading or language disorder.

AIMS

To examine the extent to which child- and item-level factors predict the probability of a correct response on a non-word repetition (NWR) task in a sample of children with persistent speech sound disorders (P-SSDs) compared with their typically developing peers.

METHODS & PROCEDURES

A total of 40 American-English-speaking children were tested on an NWR task for which the stimuli were manipulated for phonological neighbourhood density and list length. Additional measures of vocabulary and word reading were also administered.

OUTCOMES & RESULTS

Children who were typically developing were 1.82 times more likely than children with P-SSD to respond correctly. The item-level factor of phonological neighbourhood density influenced performance, but only for the P-SSD group, and only at certain list lengths. Vocabulary and word-reading ability also influenced NWR task performance.

CONCLUSIONS & IMPLICATIONS

Children with P-SSD present as a complex and heterogeneous group. Multiple factors contribute to their ability to perform phonological tasks such as NWR. As such, attention to the item-level factors in screenings and assessments is necessary to ensure that appropriate decisions are made regarding diagnosis and subsequent treatment.

WHAT THIS PAPER ADDS

What is already known on the subject? Good expressive vocabulary is important for children with speech sound disorders; it can aid in their performance on phonological processing tasks like NWR. Nonword repetition may be a helpful test/ subtest to add to assessment batteries when evaluating children with speech sound disorders. What this paper adds to existing knowledge? Vocabulary and word reading abilities must also be measured for children with SSDs, to observe the bigger picture of their linguistic abilities. What are the potential or actual clinical implications of this work? The relation between word reading and speech sound production influences performance on phonological processing tasks.

Double Trouble: Visual and Phonological Impairments in English Dyslexic Readers

Developmental dyslexia is a reading disorder characterized by problems in accurate or fluent reading. A deficiency in phonological processing is thought to underpin the reading difficulties of individuals with developmental dyslexia and a variety of explanations have been proposed including deficits in phonological awareness and verbal memory. Recent investigations have begun to suggest that developmental deficits in the acquisition of reading may also co-occur with visual processing deficits, which are particularly salient for visually complex stimuli, yet these deficits have received relatively little attention from researchers. To further explore the nature of phonological and visual processing in developmental dyslexia, we administered a series of non-reading tasks tapping both domains. Unsurprisingly, individuals with developmental dyslexia performed worse than typically developing readers in phonological tasks. More intriguingly, they also struggled with visual tasks, specifically when discriminating between novel visual patterns, and in visuo-spatial working memory, which requires greater attentional control. These findings highlight that individuals with developmental dyslexia present not only with phonological impairments but also difficulties in processing visual materials. This aspect has received limited attention in previous literature and represents an aspect of novelty of this study. The dual phonological and visual impairments suggest that developmental dyslexia is a complex disorder characterized by deficits in different cognitive mechanisms that underpin reading.

Auditory, Visual, and Cross-Modal Temporal Processing Skills Among Chinese Children With Developmental Dyslexia

The present study examined whether temporal processing (TP) is associated with reading of a non-alphabetic script, that is, Chinese. A total of 126 primary school-aged Chinese children from Taiwan (63 children with dyslexia) completed cross-modal, visual, and auditory temporal order judgment tasks and measures of Chinese reading and literacy-related skills. The results showed that typically developing children and children with dyslexia differed in all TP skills. Structural equation modeling indicated that cross-modal TP contributed independently to character recognition in the entire sample if the significant effects of phonological awareness, orthographic knowledge, and rapid automatized naming were considered. The multi-sample analysis showed that TP did not predict reading in the typical group after controlling for literacy-related skills, but visual and cross-modal TP skills independently contributed to reading in the group with dyslexia in addition to literacy-related skills. Finally, the path analysis indicated that in the typical group, separate TP skills affected reading through literacy-related skills, but visual and cross-modal TP skills had direct effects on character reading in the group with dyslexia. These findings suggest that TP is more important for reading in children with dyslexia than in typically developing children, and the roles of TP in dyslexia require further examination.

Increased variability of stimulus-driven cortical responses is associated with genetic variability in children with and without dyslexia

Individuals with dyslexia exhibit increased brainstem variability in response to sound. It is unknown as to whether increased variability extends to neocortical regions associated with audition and reading, extends to visual stimuli, and whether increased variability characterizes all children with dyslexia or, instead, a specific subset of children. We evaluated the consistency of stimulus-evoked neural responses in children with (N = 20) or without dyslexia (N = 12) as measured by magnetoencephalography (MEG). Approximately half of the children with dyslexia had significantly higher levels of variability in cortical responses to both auditory and visual stimuli in multiple nodes of the reading network. There was a significant and positive relationship between the number of risk alleles at rs6935076 in the dyslexia-susceptibility gene KIAA0319 and the degree of neural variability in primary auditory cortex across all participants. This gene has been linked with neural variability in rodents and in typical readers. These findings indicate that unstable representations of auditory and visual stimuli in auditory and other reading-related neocortical regions are present in a subset of children with dyslexia and support the link between the gene KIAA0319 and the auditory neural variability across children with or without dyslexia.

Neural correlates of phonological processing: Disrupted in children with dyslexia and enhanced in musically trained children

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First fMRI investigation of phonological processing in musically trained children.

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Greater bilateral activation with music training in regions disrupted in dyslexia.

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Implications for music training to support compensatory neural network in dyslexia.

Phonological processing has been postulated as a core area of deficit among children with dyslexia. Reduced brain activation during phonological processing in children with dyslexia has been observed in left-hemispheric temporoparietal regions. Musical training has shown positive associations with phonological processing abilities, but the neural mechanisms underlying this relationship remain unspecified. The present research aims to distinguish neural correlates of phonological processing in school-age typically developing musically trained children, musically untrained children, and musically untrained children with dyslexia utilizing fMRI. A whole-brain ANCOVA, accounting for gender and nonverbal cognitive abilities, identified a main effect of group in bilateral temporoparietal regions. Subsequent region-of-interest analyses replicated temporoparietal hypoactivation in children with dyslexia relative to typically developing children. By contrast, musically trained children showed greater bilateral activation in temporoparietal regions when compared to each musically untrained group. Therefore, musical training shows associations with enhanced bilateral activation of left-hemispheric regions known to be important for reading. Findings suggest that engagement of these regions through musical training may underlie the putative positive effects of music on reading development. This supports the hypothesis that musical training may facilitate the development of a bilateral compensatory neural network, which aids children with atypical function in left-hemispheric temporoparietal regions.

Auditory temporal perceptual learning and transfer in Chinese-speaking children with developmental dyslexia

Perceptual learning refers to the improvement of perceptual performance as a function of training. Recent studies found that auditory perceptual learning may improve phonological skills in individuals with developmental dyslexia in alphabetic writing system. However, whether auditory perceptual learning could also benefit the reading skills of those learning the Chinese logographic writing system is, as yet, unknown. The current study aimed to investigate the remediation effect of auditory temporal perceptual learning on Mandarin-speaking school children with developmental dyslexia. Thirty children with dyslexia were screened from a large pool of students in 3th-5th grades. They completed a series of pretests and then were assigned to either a non-training control group or a training group. The training group worked on a pure tone duration discrimination task for 7 sessions over 2 weeks with thirty minutes per session. Post-tests immediately after training and a follow-up test 2 months later were conducted. Analyses revealed a significant training effect in the training group relative to non-training group, as well as near transfer to the temporal interval discrimination task and far transfer to phonological awareness, character recognition and reading fluency. Importantly, the training effect and all the transfer effects were stable at the 2-month follow-up session. Further analyses found that a significant correlation between character recognition performance and learning rate mainly existed in the slow learning phase, the consolidation stage of perceptual learning, and this effect was modulated by an individuals' executive function. These findings indicate that adaptive auditory temporal perceptual learning can lead to learning and transfer effects on reading performance, and shed further light on the potential role of basic perceptual learning in the remediation and prevention of developmental dyslexia.

Cognitive mechanisms underlying the associations between inattention and reading abilities

This study aims to test cognitive skills underlying the association between inattention and reading in early primary school. Teachers rated inattention symptoms when children (N = 523-962) were 6-7 years old. Children were assessed at age 7-8 on phonological awareness, rapid automatized naming (RAN), rapid auditory and bimodal processing, vocabulary, and reading (decoding and comprehension). Phonological awareness, RAN of numbers, and vocabulary mediated the association between inattention and both decoding and comprehension. Rapid bimodal processing mediated the association between inattention and decoding, while RAN of colors mediated the association between inattention and comprehension. This study highlights mediators underlying inattention-reading associations.

Temporal precision and the capacity of auditory–verbal short-term memory

The capacity of serially ordered auditory–verbal short-term memory (AVSTM) is sensitive to the timing of the material to be stored, and both temporal processing and AVSTM capacity are implicated in the development of language. We developed a novel “rehearsal-probe” task to investigate the relationship between temporal precision and the capacity to remember serial order. Participants listened to a sub-span sequence of spoken digits and silently rehearsed the items and their timing during an unfilled retention interval. After an unpredictable delay, a tone prompted report of the item being rehearsed at that moment. An initial experiment showed cyclic distributions of item responses over time, with peaks preserving serial order and broad, overlapping tails. The spread of the response distributions increased with additional memory load and correlated negatively with participants’ auditory digit spans. A second study replicated the negative correlation and demonstrated its specificity to AVSTM by controlling for differences in visuo-spatial STM and nonverbal IQ. The results are consistent with the idea that a common resource underpins both the temporal precision and capacity of AVSTM. The rehearsal-probe task may provide a valuable tool for investigating links between temporal processing and AVSTM capacity in the context of speech and language abilities.

Revisiting the "enigma" of musicians with dyslexia: Auditory sequencing and speech abilities

Previous research has suggested a link between musical training and auditory processing skills. Musicians have shown enhanced perception of auditory features critical to both music and speech, suggesting that this link extends beyond basic auditory processing. It remains unclear to what extent musicians who also have dyslexia show these specialized abilities, considering often-observed persistent deficits that coincide with reading impairments. The present study evaluated auditory sequencing and speech discrimination in 52 adults comprised of musicians with dyslexia, nonmusicians with dyslexia, and typical musicians. An auditory sequencing task measuring perceptual acuity for tone sequences of increasing length was administered. Furthermore, subjects were asked to discriminate synthesized syllable continua varying in acoustic components of speech necessary for intraphonemic discrimination, which included spectral (formant frequency) and temporal (voice onset time [VOT] and amplitude envelope) features. Results indicate that musicians with dyslexia did not significantly differ from typical musicians and performed better than nonmusicians with dyslexia for auditory sequencing as well as discrimination of spectral and VOT cues within syllable continua. However, typical musicians demonstrated superior performance relative to both groups with dyslexia for discrimination of syllables varying in amplitude information. These findings suggest a distinct profile of speech processing abilities in musicians with dyslexia, with specific weaknesses in discerning amplitude cues within speech. Because these difficulties seem to remain persistent in adults with dyslexia despite musical training, this study only partly supports the potential for musical training to enhance the auditory processing skills known to be crucial for literacy in individuals with dyslexia. (PsycINFO Database Record

Auditory Stimulus Processing and Task Learning Are Adequate in Dyslexia, but Benefits From Regularities Are Reduced

PURPOSE

The reading deficit for people with dyslexia is typically associated with linguistic, memory, and perceptual-discrimination difficulties, whose relation to reading impairment is disputed. We proposed that automatic detection and usage of serial sound regularities for individuals with dyslexia is impaired (anchoring deficit hypothesis), leading to the formation of less reliable sound predictions. Agus, Carrión-Castillo, Pressnitzer, and Ramus, (2014) reported seemingly contradictory evidence by showing similar performance by participants with and without dyslexia in a demanding auditory task that contained task-relevant regularities. To carefully assess the sensitivity of participants with dyslexia to regularities of this task, we replicated their study.

METHOD

Thirty participants with and 24 without dyslexia performed the replicated task. On each trial, a 1-s noise stimulus was presented. Participants had to decide whether the stimulus contained repetitions (was constructed from a 0.5-s noise segment repeated twice) or not. It is implicit in this structure that some of the stimuli with repetitions were themselves repeated across trials. We measured the ability to detect within-noise repetitions and the sensitivity to cross-trial repetitions of the same noise stimuli.

RESULTS

We replicated the finding of similar mean performance. However, individuals with dyslexia were less sensitive to the cross-trial repetition of noise stimuli and tended to be more sensitive to repetitions in novel noise stimuli.

CONCLUSION

These findings indicate that online auditory processing for individuals with dyslexia is adequate but their implicit retention and usage of sound regularities is indeed impaired.

Predicting dyslexia using prereading skills: the role of sensorimotor and cognitive abilities

BACKGROUND

It is well established that phonological awareness, print knowledge and rapid naming predict later reading difficulties. However, additional auditory, visual and motor difficulties have also been observed in dyslexic children. It is examined to what extent these difficulties can be used to predict later literacy difficulties.

METHOD

An unselected sample of 267 children at school entry completed a wide battery of tasks associated with dyslexia. Their reading was tested 2, 3 and 4 years later and poor readers were identified (n = 42). Logistic regression and multiple case study approaches were used to examine the predictive validity of different tasks.

RESULTS

As expected, print knowledge, verbal short-term memory, phonological awareness and rapid naming were good predictors of later poor reading. Deficits in visual search and in auditory processing were also present in a large minority of the poor readers. Almost all poor readers showed deficits in at least one area at school entry, but there was no single deficit that characterised the majority of poor readers.

CONCLUSIONS

Results are in line with Pennington's () multiple deficits view of dyslexia. They indicate that the causes of poor reading outcome are multiple, interacting and probabilistic, rather than deterministic.

Age, dyslexia subtype and comorbidity modulate rapid auditory processing in developmental dyslexia

The nature of Rapid Auditory Processing (RAP) deficits in dyslexia remains debated, together with the specificity of the problem to certain types of stimuli and/or restricted subgroups of individuals. Following the hypothesis that the heterogeneity of the dyslexic population may have led to contrasting results, the aim of the study was to define the effect of age, dyslexia subtype and comorbidity on the discrimination and reproduction of non-verbal tone sequences. Participants were 46 children aged 8–14 (26 with dyslexia, subdivided according to age, presence of a previous language delay, and type of dyslexia). Experimental tasks were a Temporal Order Judgment (TOJ) (manipulating tone length, ISI and sequence length), and a Pattern Discrimination Task. Dyslexic children showed general RAP deficits. Tone length and ISI influenced dyslexic and control children's performance in a similar way, but dyslexic children were more affected by an increase from 2 to 5 sounds. As to age, older dyslexic children's difficulty in reproducing sequences of 4 and 5 tones was similar to that of normally reading younger (but not older) children. In the analysis of subgroup profiles, the crucial variable appears to be the advantage, or lack thereof, in processing long vs. short sounds. Dyslexic children with a previous language delay obtained the lowest scores in RAP measures, but they performed worse with shorter stimuli, similar to control children, while dyslexic-only children showed no advantage for longer stimuli. As to dyslexia subtype, only surface dyslexics improved their performance with longer stimuli, while phonological dyslexics did not. Differential scores for short vs. long tones and for long vs. short ISIs predict non-word and word reading, respectively, and the former correlate with phonemic awareness. In conclusion, the relationship between non-verbal RAP, phonemic skills and reading abilities appears to be characterized by complex interactions with subgroup characteristics.

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.

From temporal processing to developmental language disorders: mind the gap

The 'rapid temporal processing' and the 'temporal sampling framework' hypotheses have been proposed to account for the deficits in language and literacy development seen in specific language impairment and dyslexia. This paper reviews these hypotheses and concludes that the proposed causal chains between the presumed auditory processing deficits and the observed behavioural manifestation of the disorders are vague and not well established empirically. Several problems and limitations are identified. Most data concern correlations between distantly related tasks, and there is considerable heterogeneity and variability in performance as well as concerns about reliability and validity. Little attention is paid to the distinction between ostensibly perceptual and metalinguistic tasks or between implicit and explicit modes of performance, yet measures are assumed to be pure indicators of underlying processes or representations. The possibility that diagnostic categories do not refer to causally and behaviourally homogeneous groups needs to be taken seriously, taking into account genetic and neurodevelopmental studies to construct multiple-risk models. To make progress in the field, cognitive models of each task must be specified, including performance domains that are predicted to be deficient versus intact, testing multiple indicators of latent constructs and demonstrating construct reliability and validity.

Perceptual organization of speech signals by children with and without dyslexia

Developmental dyslexia is a condition in which children encounter difficulty learning to read in spite of adequate instruction. Although considerable effort has been expended trying to identify the source of the problem, no single solution has been agreed upon. The current study explored a new hypothesis, that developmental dyslexia may be due to faulty perceptual organization of linguistically relevant sensory input. To test that idea, sentence-length speech signals were processed to create either sine-wave or noise-vocoded analogs. Seventy children between 8 and 11 years of age, with and without dyslexia participated. Children with dyslexia were selected to have phonological awareness deficits, although those without such deficits were retained in the study. The processed sentences were presented for recognition, and measures of reading, phonological awareness, and expressive vocabulary were collected. Results showed that children with dyslexia, regardless of phonological subtype, had poorer recognition scores than children without dyslexia for both kinds of degraded sentences. Older children with dyslexia recognized the sine-wave sentences better than younger children with dyslexia, but no such effect of age was found for the vocoded materials. Recognition scores were used as predictor variables in regression analyses with reading, phonological awareness, and vocabulary measures used as dependent variables. Scores for both sorts of sentence materials were strong predictors of performance on all three dependent measures when all children were included, but only performance for the sine-wave materials explained significant proportions of variance when only children with dyslexia were included. Finally, matching young, typical readers with older children with dyslexia on reading abilities did not mitigate the group difference in recognition of vocoded sentences. Conclusions were that children with dyslexia have difficulty organizing linguistically relevant sensory input, but learn to do so for the structure preserved by sine-wave signals before they do so for other sorts of signal structure. These perceptual organization deficits could account for difficulties acquiring refined linguistic representations, including those of a phonological nature, although ramifications are different across affected children.

Mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring: 9-year follow-up of the gestational iodine cohort

CONTEXT

Severe iodine deficiency (ID) during gestation is associated with neurocognitive sequelae. The long-term impact of mild ID, however, has not been well characterized.

OBJECTIVE

The purpose of this study was to determine whether children born to mothers with urinary iodine concentrations (UICs) <150 μg/L during pregnancy have poorer educational outcomes in primary school than peers whose mothers did not have gestational ID (UIC ≥150 μg/L).

DESIGN

This was a longitudinal follow-up (at 9 years old) of the Gestational Iodine Cohort. Pregnancy occurred during a period of mild ID in the population, with the children subsequently growing up in an iodine-replete environment.

SETTING AND PARTICIPANTS

Participants were children whose mothers attended The Royal Hobart Hospital (Tasmania) antenatal clinics between 1999 and 2001.

MAIN OUTCOME MEASURES

Australian national curriculum and Tasmanian state curriculum educational assessment data for children in year 3 were analyzed.

RESULTS

Children whose mothers had UIC <150 μg/L had reductions of 10.0% in spelling (-41.1 points, 95% confidence interval [CI], -68.0 to -14.3, P = .003), 7.6% in grammar (-30.9 points, 95% CI, -60.2 to -1.7, P = .038), and 5.7% in English-literacy (-0.33 points, 95% CI, -0.63 to -0.03, P = .034) performance compared with children whose mothers' UICs were ≥150 μg/L. These associations remained significant after adjustment for a range of biological factors (maternal age at birth of child, gestational length at time of birth, gestational age at time of urinary iodine collection, birth weight, and sex). Differences in spelling remained significant after further adjustment for socioeconomic factors (maternal occupation and education).

CONCLUSIONS

This study provides preliminary evidence that even mild iodine deficiency during pregnancy can have long-term adverse impacts on fetal neurocognition that are not ameliorated by iodine sufficiency during childhood.

Native and novel language prosodic sensitivity in English-speaking children with and without dyslexia

Children with reading disability and normal reading development were compared in their ability to discriminate native (English) and novel language (Mandarin) from nonlinguistic sounds. Children's preference for native versus novel language sounds and for disyllables containing dominant trochaic versus non-dominant iambic stress patterns was also assessed. Participants included second and third grade monolingual native English speakers with reading disability (N = 18) and normal reading development (N = 18). Children selected from pairs of novel, native, and nonlinguistic sounds that was more like language. Both groups discriminated disyllabic linguistic sounds (native and novel) from nonlinguistic sounds. Both groups showed preference for the dominant English trochaic stress pattern over the non-dominant iambic stress pattern. Implications for development of prosodic sensitivity in relation to reading skills and future research are discussed.

A test of the magnocellular deficit theory of dyslexia in an adult sample

An influential theory of dyslexia is based on the premise that individuals with the disorder have impaired sensitivity to rapidly changing stimuli in the visual and auditory modalities, due to a dysfunction in the magnocellular channel of the visual system and its analogue in the auditory pathway. The deficit in the auditory system is thought to cause difficulties in the segmentation of speech and the formation of accurate phonological representations, leading to problems in making the grapheme-phoneme correspondences necessary for reading. In a sample of 13 adults with a history of severe reading difficulty and 18 controls, visual contrast thresholds were measured in response to an 8-Hz flickering Gaussian blob as well as a slowly modulated 8 cycles/deg Gaussian windowed grating. Auditory thresholds were measured in response to a 4-s burst of white noise, the 2nd or 3rd second of which was amplitude modulated at 100 Hz or 1 Hz. The adult reading difficulty group exhibited normal thresholds to rapidly changing stimuli in both modalities and to the slowly modulated visual stimulus, but some showed reduced sensitivity to the 1-Hz amplitude-modulated auditory stimulus. Sensitivity to amplitude modulation at slower rates has been shown to be important for segmentation of the speech stream and so may be implicated in the reading difficulty of the affected individuals. A magnocellular deficit cannot explain this impaired sensitivity, which may be the result of a reduced echoic memory span.

Contribution of temporal processing skills to reading comprehension in 8-year-olds: evidence for a mediation effect of phonological awareness

This study tested whether the association between temporal processing (TP) and reading is mediated by phonological awareness (PA) in a normative sample of 615 eight-year-olds. TP was measured with auditory and bimodal (visual-auditory) temporal order judgment tasks and PA with a phoneme deletion task. PA partially mediated the association between both auditory and bimodal TP and reading, above nonverbal abilities, vocabulary, and processing speed. PA explained a larger proportion of the association between auditory TP and reading (56% vs. 39% for bimodal TP), and most of the association between bimodal TP and reading was direct. This finding is consistent with a dual-phonological and visual-pathway model of the association between TP and reading in normative reading skills.

Are auditory and visual processing deficits related to developmental dyslexia?

The purpose of this study was to examine if children with dyslexia learning to read a consistent orthography (Greek) experience auditory and visual processing deficits and if these deficits are associated with phonological awareness, rapid naming speed and orthographic processing. We administered measures of general cognitive ability, phonological awareness, orthographic processing, short-term memory, rapid automatized naming, auditory and visual processing, and reading fluency to 21 Grade 6 children with dyslexia, 21 chronological age-matched controls and 20 Grade 3 reading age-matched controls. The results indicated that the children with dyslexia did not experience auditory processing deficits, but about half of them showed visual processing deficits. Both orthographic processing and rapid automatized naming deficits were associated with dyslexia in our sample, but it is less clear that they were associated with visual processing deficits.

Sensitivity to the acoustic correlates of lexical stress and their relationship to reading in skilled readers

The role of suprasegmental information in reading processes is a growing area of interest, and sensitivity to lexical stress has been shown to explain unique variance in reading development. However, less is known about its role in skilled reading. This study aimed to investigate the acoustic features of suprasegmental information using a same/different cross-modal matching task. Sixty-four adult participants completed standardized measures of reading accuracy, reading speed, and comprehension and performed an experimental task. The experimental task required the participants to identify whether non-speech acoustic sequences matched the characteristics of written words. The findings indicated differences in responses depending on where the lexical stress was required for the word. Moreover, evidence was found to support the view that amplitude information is part of the word knowledge retrieval process in skilled reading. The findings are discussed relative to models of reading and the role of lexical stress in lexical access.

Noise on, voicing off: Speech perception deficits in children with specific language impairment

Speech perception of four phonetic categories (voicing, place, manner, and nasality) was investigated in children with specific language impairment (SLI) (n=20) and age-matched controls (n=19) in quiet and various noise conditions using an AXB two-alternative forced-choice paradigm. Children with SLI exhibited robust speech perception deficits in silence, stationary noise, and amplitude-modulated noise. Comparable deficits were obtained for fast, intermediate, and slow modulation rates, and this speaks against the various temporal processing accounts of SLI. Children with SLI exhibited normal "masking release" effects (i.e., better performance in fluctuating noise than in stationary noise), again suggesting relatively spared spectral and temporal auditory resolution. In terms of phonetic categories, voicing was more affected than place, manner, or nasality. The specific nature of this voicing deficit is hard to explain with general processing impairments in attention or memory. Finally, speech perception in noise correlated with an oral language component but not with either a memory or IQ component, and it accounted for unique variance beyond IQ and low-level auditory perception. In sum, poor speech perception seems to be one of the primary deficits in children with SLI that might explain poor phonological development, impaired word production, and poor word comprehension.

Is developmental dyslexia modality specific? A visual-auditory comparison of Italian dyslexics

Although developmental dyslexia is often referred to as a cross-modal disturbance, tests of different modalities using the same stimuli are lacking. We compared the performance of 23 children with dyslexia and 42 chronologically matched control readers on reading versus repetition tasks and visual versus auditory lexical decision using the same stimuli. With respect to control readers, children with dyslexia were impaired only on stimuli in the visual modality; they had no deficit on the repetition and auditory lexical decision tasks. By applying the rate-amount model (Faust et al., 1999), we showed that performance of children with dyslexia on visual (but not auditory) tasks was associated with that of control readers by a linear relationship (with a 1.78 slope), suggesting that a global factor accounts for visual (but not auditory) task performance. We conclude that the processing of linguistic stimuli in the visual and auditory modalities is carried out by independent processes and that dyslexic children have a selective deficit in the visual modality.

Time perception, phonological skills and executive function in children with dyslexia and/or ADHD symptoms

BACKGROUND

Deficits in time perception (the ability to judge the duration of time intervals) have been found in children with both attention-deficit/hyperactivity disorder (ADHD) and dyslexia. This paper investigates time perception, phonological skills and executive functions in children with dyslexia and/or ADHD symptoms (AS).

METHOD

Children with dyslexia-only (n = 17), AS-only (n = 17), comorbid dyslexia+AS (n = 25), and typically developing controls (n = 42), matched for age and non-verbal ability, were assessed on measures of phonological skills, executive function and time perception (duration discrimination and time reproduction).

RESULTS

Children with dyslexia were impaired on measures of phonological skill and duration discrimination compared to children without dyslexia (though problems on duration discrimination appeared to be attributable to mild symptoms of inattention in this group). In contrast, children with AS exhibited impairments on measures of both time perception and executive function compared to children without AS. Children with dyslexia+AS showed an additive combination of the deficits associated with dyslexia-only and AS-only.

CONCLUSIONS

Dyslexia and AS appear to be associated with distinct patterns of cognitive deficit, which are present in combination in children with dyslexia+AS.

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.

Perception of non-verbal auditory stimuli in Italian dyslexic children

Auditory temporal processing deficits have been proposed as the underlying cause of phonological difficulties in Developmental Dyslexia. The hypothesis was tested in a sample of 20 Italian dyslexic children aged 8-14, and 20 matched control children. Three tasks of auditory processing of non-verbal stimuli, involving discrimination and reproduction of sequences of rapidly presented short sounds were expressly created. Dyslexic subjects performed more poorly than control children, suggesting the presence of a deficit only partially influenced by the duration of the stimuli and of inter-stimulus intervals (ISIs).

Auditory processing and early literacy skills in a preschool and kindergarten population

Although the relationship between auditory processing and reading-related skills has been investigated in school-age populations and in prospective studies of infants, understanding of the relationship between these variables in the period immediately preceding formal reading instruction is sparse. In this cross-sectional study, auditory processing, phonological awareness, early literacy skills, and general ability were assessed in a mixed sample of 88 three- to six-year-old children both cross-sectionally and longitudinally. Results from both cross-sectional and longitudinal analyses suggest the importance of early auditory rise time sensitivity in developing phonological awareness skills, especially in the development of rhyme awareness.

Adults with dyslexia are impaired in categorizing speech and nonspeech sounds on the basis of temporal cues

Developmental dyslexia is characterized by severe reading and spelling difficulties that are persistent and resistant to the usual didactic measures and remedial efforts. It is well established that a major cause of these problems lies in poorly specified representations of speech sounds. One hypothesis states that this phonological deficit results from a more fundamental deficit in auditory processing. Despite substantial research effort, the specific nature of these auditory problems remains debated. A first controversy concerns the speech specificity of the auditory processing problems: Can they be reduced to more basic auditory processing, or are they specific to the perception of speech sounds? A second topic of debate concerns the extent to which the auditory problems are specific to the processing of rapidly changing temporal information or whether they encompass a broader range of complex spectro-temporal processing. By applying a balanced design with stimuli that were adequately controlled for acoustic complexity, we show that adults with dyslexia are specifically impaired at categorizing speech and nonspeech sounds that differ in terms of rapidly changing acoustic cues (i.e., temporal cues), but that they perform adequately when categorizing steady-state speech and nonspeech sounds. Thus, we show that individuals with dyslexia have an auditory temporal processing deficit that is not speech-specific.

Auditory stream biasing in children with reading impairments

Reading impairments have previously been associated with auditory processing differences. We examined auditory stream biasing, a global aspect of auditory temporal processing. Children with reading impairments, control children and adults heard a 10 s long stream-bias-inducing sound sequence (a repeating 1000 Hz tone) and a test sequence (eight repetitions of two pure tones of 1000 and 1420 Hz in an XYX-XYX... pattern) with a variable delay interval (from 0.09 to 8 s) between the two sequences. Reading-impaired children had a significantly lower proportion of streamed responses than control children and adults. Streamed responses in reading-impaired participants differed according to their musical experience, but musically experienced reading-impaired participants were still significantly different from musically experienced controls. Reading impairments are associated with global differences in auditory integration, and musical experience needs to be considered when investigating auditory processing capabilities.

Directional effects between rapid auditory processing and phonological awareness in children

BACKGROUND

Deficient rapid auditory processing (RAP) has been associated with early language impairment and dyslexia. Using an auditory masking paradigm, children with language disabilities perform selectively worse than controls at detecting a tone in a backward masking (BM) condition (tone followed by white noise) compared to a forward masking (FM) condition (tone preceded by white noise). Tallal's (1980) auditory processing hypothesis posits that abnormal RAP leads to reduced (or impaired) phonological awareness (PA), resulting in reading and language difficulties. Alternative theories suggest that impaired PA may have more of a top-down effect on auditory processing.

METHODS

The current study examines RAP in children tested at two time points, average age 5.6 and average age 8.3, in order to test causal relations between RAP and PA in a path analysis. Additional hierarchical regressions examine how well RAP predicts reading ability when accounting for PA and vocabulary.

RESULTS

The path analysis indicates a top-down effect, such that PA has a larger impact on BM over time than the reverse. Regressions indicate no direct impact of RAP on reading ability.

DISCUSSION

The path analysis provides evidence against the auditory processing hypothesis and instead suggests that between the ages of 5 and 8 it is variability in early phonological representations that predicts subsequent lower-level rapid auditory processing.

Computer-based training with ortho-phonological units in dyslexic children: new investigations

This study aims to show that training using a computer game incorporating an audio-visual phoneme discrimination task with phonological units, presented simultaneously with orthographic units, might improve literacy skills. Two experiments were conducted, one in secondary schools with dyslexic children (Experiment 1) and the other in a speech-therapy clinic with individual case studies (Experiment 2). A classical pre-test, training, post-test design was used. The main findings indicated an improvement in reading scores after short intensive training (10 h) in Experiment 1 and progress in the reading and spelling scores obtained by the dyslexic children (training for 8 h) in Experiment 2. These results are discussed within the frameworks of both the speech-specific deficit theory of dyslexia and the connectionist models of reading development.

Poor performance on serial visual tasks in persons with reading disabilities: impaired working memory?

The present study investigates the performance of persons with reading disabilities (PRD) on a variety of sequential visual-comparison tasks that have different working-memory requirements. In addition, mediating relationships between the sequential comparison process and attention and memory skills were looked for. Our findings suggest that PRD perform worse than normally achieving readers (NAR) when the task requires more than a minimal amount of working memory, unrelated to presentation rate. We also demonstrate high correlations between performance on the task with the most working-memory demands and reading-related skills, suggesting that poor working-memory abilities may be one of the underlying mechanisms of dyslexia. The mediating model analysis indicates that order judgment tasks are mediating to verbal working memory, suggesting that visual sequence memory precedes auditory sequence memory. We further suggest that visual tasks involving sequential comparisons could probe for poor working memory in PRD.

A randomized, controlled study of computer-based intervention in middle school struggling readers

The current study was conducted to test the premise that computer-based intervention that targets auditory temporal processing combined with language exercises (Fast ForWord) is effective in remediating children with disorders of language and reading. Sixty-five middle school struggling readers were randomly assigned to one of five groups and over a 12-week-period received one of the following interventions: (1) two phases of intervention with Fast ForWord (FFW, experimental group), (2) two phases of intervention with SuccessMaker (SM, active control group), (3) FFW followed by SM, (4) SM followed by FFW, or (5) no intervention beyond the regular class curriculum (developmental control group). Changes in reading, phonemic awareness, spelling and language skills were assessed via a repeated measures MANOVA. Results indicated significant within-subjects effects (i.e., change for all participants over time), but no between-subject group differences, failing to show that Fast ForWord resulted in any gains over and above those seen in the other groups.

The role of visual and auditory temporal processing for Chinese children with developmental dyslexia

This study examined temporal processing in relation to Chinese reading acquisition and impairment. The performances of 26 Chinese primary school children with developmental dyslexia on tasks of visual and auditory temporal order judgement, rapid naming, visual-orthographic knowledge, morphological, and phonological awareness were compared with those of 26 reading level ability controls (RL) and 26 chronological age controls (CA). Dyslexic children performed worse than the CA group but similar to the RL group on measures of accurate processing of auditory and visual-order stimuli, rapid naming, morphological awareness, and phonological awareness and a minority performed worse on the two temporal processing tasks. However, hierarchical regression analyses revealed that visual but not auditory temporal processing contributed unique variance to Chinese character recognition even with other cognitive measures controlled, suggesting it may be as important a correlate of reading ability in Chinese as in alphabetic scripts.

Dichotic listening deficits in children with dyslexia

Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant-vowel (CV) pairs were administered to two groups of right-handed 11-year-old children, one group diagnosed with developmental dyslexia and an age-matched control group. Dyslexic children performed more poorly than controls from their left ears when listening to digits and words and from their right ears when listening to CVs. Direction of ear advantage varied across individuals in both groups when tested with digits and CVs, but ear advantage was stable with words. Several factors that may have contributed to inconsistencies in direction of ear advantage are discussed. When the children were tested in a directed response mode, degree of ear advantage differed significantly between groups with both words and digits. More dyslexic than control children demonstrated clinically significant reductions in dichotic listening performance, but no uniform pattern of deficit emerged. Only the double correct score and the left ear score with CV pairs were predictive of word recognition performance in dyslexic children. Binaural integration deficits are present in some children with dyslexia. Auditory processing disorder assessment may help delineate factors that underlie or are associated with reading impairment in this population.

Does the auditory saltation stimulus distinguish dyslexic from competently reading adults?

PURPOSE

Where the auditory saltation illusion has been used as a measure of auditory temporal processing (ATP) in dyslexia, conflicting results have been apparent (cf. R. Hari & P. Kiesilä, 1996; M. Kronbichler, F. Hutzler, & H. Wimmer, 2002). This study sought to re-examine these findings by investigating whether dyslexia is characterized by poor saltation task performance and whether saltation thresholds are related to reading and phonological processing within groups of either dyslexic or competent readers.

METHOD

Nineteen dyslexic and 20 competently reading adults (18-64 years of age) participated. Participants completed 2 runs of a 2-alternative forced-choice saltation task, along with standard measures of reading and phonological processing.

RESULTS

Although overall poorer saltation thresholds were apparent in the dyslexic group, the threshold distributions overlapped considerably, with thresholds alone unable to predict group membership at a level significantly greater than chance. Neither strong nor significant correlations were observed among saltation thresholds, reading, and phonological processing skills within either group.

CONCLUSION

The results of this study do not support suggestions of impaired ATP in dyslexia or associations among ATP, reading, and phonological processing. However, it is proposed that increased within- and between-subject variability in auditory thresholds might be a more valuable marker of dyslexia than the thresholds themselves. Implications of this observation for dyslexia research are discussed.

Delayed detection of tonal targets in background noise in dyslexia

Individuals with developmental dyslexia are often impaired in their ability to process certain linguistic and even basic non-linguistic auditory signals. Recent investigations report conflicting findings regarding impaired low-level binaural detection mechanisms associated with dyslexia. Binaural impairment has been hypothesized to stem from a general low-level processing disorder for temporally fine sensory stimuli. Here we use a new behavioral paradigm to address this issue. We compared the response times of dyslexic listeners and their matched controls in a tone-in-noise detection task. The tonal signals were either Huggins Pitch (HP), a stimulus requiring binaural processing to elicit a pitch percept, or a pure tone-perceptually similar but physically very different signals. The results showed no difference between the two groups specific to the processing of HP and thus no evidence for a binaural impairment in dyslexia. However, dyslexic subjects exhibited a general difficulty in extracting tonal objects from background noise, manifested by a globally delayed detection speed.

Speech development patterns and phonological awareness in preschool children

To examine the association between speech production and early literacy skills, this study of 102 preschool children looked at phonological awareness in relation to whether children were delayed, typical, or advanced in their articulation of consonants. Using a developmental typology inspired by some of the literature on speech development (Kahn and Lewis, The Kahn-Lewis phonological analysis, 1986; Shriberg, Journal of Speech and Hearing Research 36(1):105-140, 1993a), we found that failure to master the early-8 consonants and a greater prevalence of certain types of production errors were associated with deficient phonological awareness. We also found that children who made no consonant errors had advanced phonological awareness relative to other children in the sample. In all cases, both productive speech patterns and speech errors were more closely linked with rhyme awareness than with phoneme awareness. The association between speech production and rhyme awareness may provide some new directions for the early preschool assessment of risk for reading problems.

Reception class predictors of literacy skills

BACKGROUND

In the last decade, there has been a growing interest, both in the UK and abroad, in developing early screening tests for dyslexia that can be used with very young children. In addition to measures of literacy achievement, such screening tests typically aim to identify underlying difficulties, such as phonological deficits, that might hinder a child's educational progress. The Dyslexia Early Screening Test (DEST; Nicolson & Fawcett, 1996) is an example of such a test that combines attainment and diagnostic indicators.

AIM

The study reported assessed the ability of the DEST to predict future literacy skills in contrast with the prediction afforded by school-based measures, such as letter knowledge.

SAMPLE

Participants were 45 boys attending a reception class, with a mean age of 4.87 years at the start of the study and 6.63 years at the end.

METHODS

Measures of literacy skills, phonological awareness, verbal memory, motor skill, and auditory processing were assessed using the DEST as the initial screening tool at Phase 1. Measures of letter knowledge, non-word reading, and rhyme judgment were taken at Phase 2. Phase 3 measures, 14 months after the start of the study, comprised single-word reading and spelling. At Phase 4, some 22 months after the beginning of the study, measures of reading and spelling ability were assessed again.

RESULTS

Individual subtests of the DEST were more predictive of later literacy skills than the global screening test's score (the 'at risk quotient'). Better predictors were the DEST subtest of sound order and rapid automatized naming, together with the school attainment measure of letter knowledge.

CONCLUSIONS

Although some DEST subtests did offer predictors of future literacy skills, school-based measures of letter knowledge may be equally valid as assessment measures. Additionally, the results question the usefulness of combining measures to form an 'at risk' index of future literacy difficulties, particularly in the age range assessed.