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The acquisition of letter-speech sound correspondences is a fundamental process underlying reading development, one that could be influenced by several linguistic and domain-general cognitive factors. In the current study, we mimicked the first steps of this process by examining behavioral trajectories of audiovisual associative learning in 110 7- to 12-year-old children with and without dyslexia. Children were asked to learn the associations between eight novel symbols and native speech sounds in a brief training and subsequently read words and pseudowords written in the artificial orthography. We then investigated the influence of auditory attention as one of the putative domain-general factors influencing associative learning. To this aim, we assessed children with experimental measures of auditory sustained selective attention and interference control. Our results showed shallower learning trajectories in children with dyslexia, especially during the later phases of the training blocks. Despite this, children with dyslexia performed similarly to typical readers on the post-training reading tests using the artificial orthography. Better auditory sustained selective attention and interference control skills predicted greater response accuracy during training. Sustained selective attention was also associated with the ability to apply these novel correspondences in the reading tests. Although this result has the limitations of a correlational design, it denotes that poor attentional skills may constitute a risk during the early stages of reading acquisition, when children start to learn letter-speech sound associations. Importantly, our findings underscore the importance of examining dynamics of learning in reading acquisition as well as individual differences in more domain-general attentional factors., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

There is an ongoing debate whether phonological deficits in dyslexics should be attributed to (a) less specified representations of speech sounds, like suggested by studies in young children with a familial risk for dyslexia, or (b) to an impaired access to these phonemic representations, as suggested by studies in adults with dyslexia. These conflicting findings are rooted in between study differences in sample characteristics and/or testing techniques. The current study uses the same multivariate functional MRI (fMRI) approach as previously used in adults with dyslexia to investigate phonemic representations in 30 beginning readers with a familial risk and 24 beginning readers without a familial risk of dyslexia, of whom 20 were later retrospectively classified as dyslexic. Based on fMRI response patterns evoked by listening to different utterances of /bA/ and /dA/ sounds, multivoxel analyses indicate that the underlying activation patterns of the two phonemes were distinct in children with a low family risk but not in children with high family risk. However, no group differences were observed between children that were later classified as typical versus dyslexic readers, regardless of their family risk status, indicating that poor phonemic representations constitute a risk for dyslexia but are not sufficient to result in reading problems. We hypothesize that poor phonemic representations are trait (family risk) and not state (dyslexia) dependent, and that representational deficits only lead to reading difficulties when they are present in conjunction with other neuroanatomical or-functional deficits., (© 2019 John Wiley & Sons Ltd.)

Listeners adjust their phonetic categories to cope with variations in the speech signal (phonetic recalibration). Previous studies have shown that lipread speech (and word knowledge) can adjust the perception of ambiguous speech and can induce phonetic adjustments (Bertelson, Vroomen, & de Gelder in Psychological Science, 14(6), 592-597, 2003; Norris, McQueen, & Cutler in Cognitive Psychology, 47(2), 204-238, 2003). We examined whether orthographic information (text) also can induce phonetic recalibration. Experiment 1 showed that after exposure to ambiguous speech sounds halfway between /b/ and /d/ that were combined with text (b or d) participants were more likely to categorize auditory-only test sounds in accordance with the exposed letters. Experiment 2 replicated this effect with a very short exposure phase. These results show that listeners adjust their phonetic boundaries in accordance with disambiguating orthographic information and that these adjustments show a rapid build-up.

The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter 'a' was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.

Selective attention to relevant sound properties is essential for everyday listening situations. It enables the formation of different perceptual representations of the same acoustic input and is at the basis of flexible and goal-dependent behavior. Here, we investigated the role of the human auditory cortex in forming behavior-dependent representations of sounds. We used single-trial fMRI and analyzed cortical responses collected while subjects listened to the same speech sounds (vowels /a/, /i/, and /u/) spoken by different speakers (boy, girl, male) and performed a delayed-match-to-sample task on either speech sound or speaker identity. Univariate analyses showed a task-specific activation increase in the right superior temporal gyrus/sulcus (STG/STS) during speaker categorization and in the right posterior temporal cortex during vowel categorization. Beyond regional differences in activation levels, multivariate classification of single trial responses demonstrated that the success with which single speakers and vowels can be decoded from auditory cortical activation patterns depends on task demands and subject's behavioral performance. Speaker/vowel classification relied on distinct but overlapping regions across the (right) mid-anterior STG/STS (speakers) and bilateral mid-posterior STG/STS (vowels), as well as the superior temporal plane including Heschl's gyrus/sulcus. The task dependency of speaker/vowel classification demonstrates that the informative fMRI response patterns reflect the top-down enhancement of behaviorally relevant sound representations. Furthermore, our findings suggest that successful selection, processing, and retention of task-relevant sound properties relies on the joint encoding of information across early and higher-order regions of the auditory cortex.

In transparent alphabetic languages, the expected standard for complete acquisition of letter-speech sound associations is within one year of reading instruction. The neural mechanisms underlying the acquisition of letter-speech sound associations have, however, hardly been investigated. The present article describes an ERP study with beginner and advanced readers in which the influence of letters on speech sound processing is investigated by comparing the MMN to speech sounds presented in isolation with the MMN to speech sounds accompanied by letters. Furthermore, SOA between letter and speech sound presentation was manipulated in order to investigate the development of the temporal window of integration for letter-speech sound processing. Beginner readers, despite one year of reading instruction, showed no early letter-speech sound integration, that is, no influence of the letter on the evocation of the MMN to the speech sound. Only later in the difference wave, at 650 msec, was an influence of the letter on speech sound processing revealed. Advanced readers, with 4 years of reading instruction, showed early and automatic letter-speech sound processing as revealed by an enhancement of the MMN amplitude, however, at a different temporal window of integration in comparison with experienced adult readers. The present results indicate a transition from mere association in beginner readers to more automatic, but still not "adult-like," integration in advanced readers. In contrast to general assumptions, the present study provides evidence for an extended development of letter-speech sound integration.

Recently brain imaging evidence indicated that letter/speech-sound integration, necessary for establishing fluent reading, takes place in auditory association areas and that the integration is influenced by stimulus onset asynchrony (SOA) between the letter and the speech-sound. In the present study, we used a specific ERP measure known for its automatic character, the mismatch negativity (MMN), to investigate the time course and automaticity of letter/speech-sound integration. We studied the effect of visual letters and SOA on the MMN elicited by a deviant speech-sound. We found a clear enhancement of the MMN by simultaneously presenting a letter, but without changing the auditory stimulation. This enhancement diminishes linearly with increasing SOA. These results suggest that letters and speech-sounds are processed as compound stimuli early and automatically in the auditory association cortex of fluent readers and that this processing is strongly dependent on timing.

In speech perception, extraction of meaning from complex streams of sounds is surprisingly fast and efficient. By tracking the neural time course of syllable processing with magnetoencephalography we show that this continuous construction of meaning-based representations is aided by both top-down (context-based) expectations and bottom-up (acoustic-phonetic) cues in the speech signal. Syllables elicited a sustained response at 200-600 ms (N400m) which became most similar to that evoked by words when the expectation for meaningful speech was increased by presenting the syllables among words and sentences or using sentence-initial syllables. This word-like cortical processing of meaningless syllables emerged at the build-up of the N400m response, 200-300 ms after speech onset, during the transition from perceptual to lexical-semantic analysis. These findings show that the efficiency of meaning-based analysis of speech is subserved by a cortical system finely tuned to lexically relevant acoustic-phonetic and contextual cues.

Objective: Ample behavioral evidence suggests that distributional properties of the language environment influence the processing of speech. Yet, how these characteristics are reflected in neural processes remains largely unknown. The present ERP study investigates neurophysiological correlates of phonotactic probability: the distributional frequency of phoneme combinations., Methods: We employed an ERP measure indicative of experience-dependent auditory memory traces, the mismatch negativity (MMN). We presented pairs of non-words that differed by the degree of phonotactic probability in a modified passive oddball design that minimizes the contribution of acoustic processes., Results: In Experiment 1 the non-word with high phonotactic probability (notsel) elicited a significantly enhanced MMN as compared to the non-word with low phonotactic probability (notkel). In Experiment 2 this finding was replicated with a non-word pair with a smaller acoustic difference (notsel-notfel). An MMN enhancement was not observed in a third acoustic control experiment with stimuli having comparable phonotactic probability (so-fo)., Conclusions: Our data suggest that auditory cortical responses to phoneme clusters are modulated by statistical regularities of phoneme combinations., Significance: This study indicates that the language environment is relevant in shaping the neural processing of speech. Furthermore, it provides a potentially useful design for investigating implicit phonological processing in children with anomalous language functions like dyslexia.

Ample evidence suggests that developmental dyslexia results from a phonological deficit that may not be reducible to a low-level auditory deficit. Yet, on-line phonological processing (in)capacities in dyslexics remain virtually unexplored, as studies have typically focused on either meta-phonological awareness tasks or, at the other extreme, basic perceptual tasks. The present study investigates event-related potential (ERP) correlates of implicit phonological processing during the recognition of spoken words in dyslexic and normally reading children (7-10 years). We examined general ERP morphology and alliteration priming effects on ERP measures in an auditory lexical decision task. Primes were words (Experiment 1) and non-words (Experiment 2). Alliteration priming effects suggested a distinct pattern of normal versus anomalous aspects of spoken word processing in dyslexic children. Whereas dyslexics showed deviant priming effects in earlier time windows encompassing the N1 and N2, later N400 priming effects were comparable to those of normal readers. The same pattern of results was also present in group comparisons of general ERP morphology. These findings suggest that dyslexics have selective processing anomalies at an earlier phonetic/phonological level, while processing at a later phonological/lexical level proceeds normally. In particular, our results indicate an anomalous contribution of phonological (word onset) information to the processing of spoken words, which may be related to time-course aspects of phonetic/phonological processing.

Objective: We investigated event-related potential (ERP) correlates of developmental changes in spoken word recognition during early school years. We focused on implicit processing of word onsets as this may change considerably due to vocabulary growth and reading acquisition., Methods: Subjects were pre-schoolers (5-6 years), beginning readers (7-8 years) and adults. Two experiments examined phonological onset priming effects on ERP measures in an auditory lexical decision task. Primes were words (Expt. 1) or non-words (Expt. 2)., Results: ERPs elicited by words showed clear developmental changes in ERP latency and morphology, especially with regard to early negativities like the N1. Prominent priming effects were an enhanced N400 amplitude due to alliterating word primes in beginning readers, and typical phonological N400 reductions due to alliterating non-word primes in all groups. Priming further led to opposite early effects with word primes (N1/N(200) reduction) vs. non-word primes (P1/N1 enhancement) in all groups., Conclusions: These changes in ERP morphology and priming effects suggest that the lexical system undergoes substantial restructuring at the level of phonological processing and representation. In particular, our results indicate distinct processing of word onsets in beginning readers, confirming that vocabulary growth and the acquisition of reading may critically contribute to the formation of a fully segmental lexical system.