Maturation of consonant perception, but not vowel perception, predicts lexical skills at 12 months.

Consonants and vowels differentially contribute to lexical acquisition. From 8 months on, infants' preferential reliance on consonants has been shown to predict their lexical outcome. Here, the predictive value of German-learning infants' (n = 58, 29 girls, 29 boys) trajectories of consonant and vowel perception, indicated by the electrophysiological mismatch response, across 2, 6, and 10 months for later lexical acquisition was studied. The consonant-perception trajectory from 2 to 6 months (ß = -2.95) and 6 to 10 months (ß = -.91), but not the vowel-perception trajectory, significantly predicted receptive vocabulary at 12 months. These results reveal an earlier predictive value of consonant perception for word learning than previously found, and a particular role of the longitudinal maturation of this skill in lexical acquisition.

Associated functional network development and language abilities in children.

During childhood, the brain is gradually converging to the efficient functional architecture observed in adults. How the brain's functional architecture evolves with age, particularly in young children, is however, not well understood. We examined the functional connectivity of the core language regions, in association with cortical growth and language abilities, in 175 young children in the age range of 4 to 9 years. We analyzed the brain's developmental changes using resting-state functional and T1-weighted structural magnetic resonance imaging data. The results showed increased functional connectivity strength with age between the pars triangularis of the left inferior frontal gyrus and left temporoparietal regions (cohen's d = 0.54, CI: 0.24 - 0.84), associated with children's language abilities. Stronger functional connectivity between bilateral prefrontal and temporoparietal regions was associated with better language abilities regardless of age. In addition, the stronger functional connectivity between the left inferior frontal and temporoparietal regions was associated with larger surface area and thinner cortical thickness in these regions, which in turn was associated with superior language abilities. Thus, using functional and structural brain indices, coupled with behavioral measures, we elucidate the association of functional language network development, language ability, and cortical growth, thereby adding to our understanding of the neural basis of language acquisition in young children.

The emergence of dyslexia in the developing brain.

Developmental dyslexia, a severe deficit in literacy learning, is a neurodevelopmental learning disorder. Yet, it is not clear whether existing neurobiological accounts of dyslexia capture potential predispositions of the deficit or consequences of reduced reading experience. Here, we longitudinally followed 32 children from preliterate to school age using functional and structural magnetic resonance imaging techniques. Based on standardised and age-normed reading and spelling tests administered at school age, children were classified as 16 dyslexic participants and 16 controls. This longitudinal design allowed us to disentangle possible neurobiological predispositions for developing dyslexia from effects of individual differences in literacy experience. In our sample, the disorder can be predicted already before literacy learning from auditory cortex gyrification and aberrant downstream connectivity within the speech processing system. These results provide evidence for the notion that dyslexia may originate from an atypical maturation of the speech network that precedes literacy instruction.

Seven-year-olds recall non-adjacent dependencies after overnight retention.

Becoming a successful speaker depends on acquiring and learning grammatical dependencies between neighboring and non-neighboring linguistic elements (non-adjacent dependencies; NADs). Previous studies have demonstrated children's and adults' ability to distinguish NADs from NAD violations right after familiarization. However, demonstrating NAD recall after retention is crucial to demonstrate a lasting effect of NAD learning. We tested 7-year-olds' NAD learning in a natural, non-native language on one day and NAD recall on the next day by means of event-related potentials (ERPs). Our results revealed ERPs with a more positive amplitude to NAD violations than correct NADs after familiarization on day one, but ERPs with a more negative amplitude to NAD violations on day two. This change from more positive to more negative ERPs to NAD violations possibly indicates that children's representations of NADs changed during an overnight retention period, potentially associated with children's NAD learning. Indeed, our descriptive analyses showed that both ERP patterns (i.e., day one: positive, day two: negative) were related to stronger behavioral improvement (i.e., more correct answers on day two compared to day one) in a grammaticality judgment task from day one to day two. We suggest these findings to indicate that children successfully built associative representations of NADs on day one and then strengthened these associations during overnight retention, revealing NAD recall on day two. The present results suggest that 7-year-olds readily track NADs in a natural, non-native language and are able to recall NADs after a retention period involving sleep, providing evidence of a lasting effect of NAD learning.

The emergence of long-range language network structural covariance and language abilities.

Language skills increase as the brain matures. Language processing, especially the comprehension of syntactically complex sentences, is supported by a brain network involving functional interactions between left inferior frontal and left temporal regions in the adult brain, with reduced functional interactions in children. Here, we examined the gray matter covariance of the cortical thickness network relevant for syntactic processing in relation to language abilities in preschool children (i.e., 5-year-olds) and analyzed the developmental changes of the cortical thickness covariance cross-sectionally by comparing preschool children, school age children, and adults. Further, to demonstrate the agreement of cortical thickness covariance and white matter connectivity, tractography analyses were performed. Covariance of language-relevant seeds in preschoolers was strongest in contralateral homologous regions. A more adult-like, significant cortical thickness covariance between left frontal and left temporal regions, however, was observed in preschoolers with advanced syntactic language abilities. By comparing the three age groups, we could show that the cortical thickness covariance pattern from the language-associated seeds develops progressively from restricted in preschoolers to widely-distributed brain regions in adults. In addition, our results suggest that the cortical thickness covariance difference of the left inferior frontal gyrus to superior temporal gyrus/sulcus between preschoolers and adults is accompanied by distinctions in the white matter tracts linking these two areas, with more mature white matter in the arcuate fasciculus in adults compared to preschoolers. These findings provide anatomical evidence for developmental changes in language both from the perspective of gray matter structure co-variation within the language network and white matter maturity as the anatomical substrate for the structural covariance.

NRSN1 associated grey matter volume of the visual word form area reveals dyslexia before school.

Literacy learning depends on the flexibility of the human brain to reconfigure itself in response to environmental influences. At the same time, literacy and disorders of literacy acquisition are heritable and thus to some degree genetically predetermined. Here we used a multivariate non-parametric genetic model to relate literacy-associated genetic variants to grey and white matter volumes derived by voxel-based morphometry in a cohort of 141 children. Subsequently, a sample of 34 children attending grades 4 to 8, and another sample of 20 children, longitudinally followed from kindergarten to first grade, were classified as dyslexics and controls using linear binary support vector machines. The NRSN1-associated grey matter volume of the 'visual word form area' achieved a classification accuracy of ~ 73% in literacy-experienced students and distinguished between later dyslexic individuals and controls with an accuracy of 75% at kindergarten age. These findings suggest that the cortical plasticity of a region vital for literacy might be genetically modulated, thereby potentially preconstraining literacy outcome. Accordingly, these results could pave the way for identifying and treating the most common learning disorder before it manifests itself in school.

Predicting early signs of dyslexia at a preliterate age by combining behavioral assessment with structural MRI.

BACKGROUND: Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only. METHODS: We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade. RESULTS: The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%). The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p<.05). CONCLUSIONS: Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role.

Facial speech gestures: the relation between visual speech processing, phonological awareness, and developmental dyslexia in 10-year-olds.

Successful communication in everyday life crucially involves the processing of auditory and visual components of speech. Viewing our interlocutor and processing visual components of speech facilitates speech processing by triggering auditory processing. Auditory phoneme processing, analyzed by event-related brain potentials (ERP), has been shown to be associated with impairments in reading and spelling (i.e. developmental dyslexia), but visual aspects of phoneme processing have not been investigated in individuals with such deficits. The present study analyzed the passive visual Mismatch Response (vMMR) in school children with and without developmental dyslexia in response to video-recorded mouth movements pronouncing syllables silently. Our results reveal that both groups of children showed processing of visual speech stimuli, but with different scalp distribution. Children without developmental dyslexia showed a vMMR with typical posterior distribution. In contrast, children with developmental dyslexia showed a vMMR with anterior distribution, which was even more pronounced in children with severe phonological deficits and very low spelling abilities. As anterior scalp distributions are typically reported for auditory speech processing, the anterior vMMR of children with developmental dyslexia might suggest an attempt to anticipate potentially upcoming auditory speech information in order to support phonological processing, which has been shown to be deficient in children with developmental dyslexia.

Genetic dyslexia risk variant is related to neural connectivity patterns underlying phonological awareness in children.

Phonological awareness is the best-validated predictor of reading and spelling skill and therefore highly relevant for developmental dyslexia. Prior imaging genetics studies link several dyslexia risk genes to either brain-functional or brain-structural factors of phonological deficits. However, coherent evidence for genetic associations with both functional and structural neural phenotypes underlying variation in phonological awareness has not yet been provided. Here we demonstrate that rs11100040, a reported modifier of SLC2A3, is related to the functional connectivity of left fronto-temporal phonological processing areas at resting state in a sample of 9- to 12-year-old children. Furthermore, we provide evidence that rs11100040 is related to the fractional anisotropy of the arcuate fasciculus, which forms the structural connection between these areas. This structural connectivity phenotype is associated with phonological awareness, which is in turn associated with the individual retrospective risk scores in an early dyslexia screening as well as to spelling. These results suggest a link between a dyslexia risk genotype and a functional as well as a structural neural phenotype, which is associated with a phonological awareness phenotype. The present study goes beyond previous work by integrating genetic, brain-functional and brain-structural aspects of phonological awareness within a single approach. These combined findings might be another step towards a multimodal biomarker for developmental dyslexia.

Semantic priming of progression features in events.

Event knowledge includes persons and objects and their roles in the event. This study investigated whether the progression of patients from a source to a resulting feature, such as the progression of hair that is cut from long to short, forms part of event representations. Subjects were presented with an event prime followed by two adjectives and asked to judge whether the adjectives were interrelated. Results showed that the semantic interrelation of two adjectives is recognized faster and more accurately when the adjectives denote source and resulting features of the patient of the primed event ("cutting": long-short). Furthermore, we found that presenting an event-related adjective in combination with an unrelated adjective makes it more difficult to recognize that the two adjectives are not interrelated, but only when the event-related adjective denotes a source feature. We argue that an inference mechanism automatically completes the representation of the event. We conclude that source and resulting features are represented in a goal-directed and chronological way.

Perceptual anchoring: Children with dyslexia benefit less than controls from contextual repetitions in speech processing.

OBJECTIVES: Individuals with dyslexia perceive and utilize statistical features in the auditory input deficiently. The present study investigates whether affected children also benefit less from repeating context tones as perceptual anchors for subsequent speech processing. METHODS: In an event-related potential study, eleven-year-old children with dyslexia (n = 21) and without dyslexia (n = 20) heard syllable pairs, with the first syllable either receiving a constant pitch (anchor) or variable pitch (no-anchor), while second syllables were identical across conditions. RESULTS: Children with and without dyslexia showed smaller auditory P2 responses to constant-pitch versus variable-pitch first syllables, while only control children additionally showed smaller N1 and faster P1 responses. This suggests less automatic processing of anchor repetitions in dyslexia. For the second syllables, both groups showed faster P2 responses following anchor than no-anchor first syllables, but only controls additionally showed smaller P2 responses. CONCLUSIONS: Children with and without dyslexia show differences in anchor effects. While both groups seem to allocate less attention to speech stimuli after contextual repetitions, children with dyslexia display less facilitation in speech processing from acoustic anchors. SIGNIFICANCE: Altered anchoring in the linguistic domain may contribute to the difficulties of individuals with dyslexia in establishing long-term representations of speech.

Longitudinal trajectories of electrophysiological mismatch responses in infant speech discrimination differ across speech features.

Infants rapidly advance in their speech perception, electrophysiologically reflected in the transition from an immature, positive-going to an adult-like, negative-going mismatch response (MMR) to auditory deviancy. Although the MMR is a common tool to study speech perception development, it is not yet completely understood how different speech contrasts affect the MMR's characteristics across development. Thus, a systematic longitudinal investigation of the MMR's maturation depending on speech contrast is necessary. We here longitudinally explored the maturation of the infant MMR to four critical speech contrasts: consonant, vowel, vowel-length, and pitch. MMRs were obtained when infants (n = 58) were 2, 6 and 10 months old. To evaluate the maturational trajectory of MMRs, we applied second-order latent growth curve models. Results showed positive-going MMR amplitudes to all speech contrasts across all assessment points that decreased over time towards an adult-like negativity. Notably, the developmental trajectories of speech contrasts differed, implying that infant speech perception matures with different rates and trajectories throughout the first year, depending on the studied auditory feature. Our results suggest that stimulus-dependent maturational trajectories need to be considered when drawing conclusions about infant speech perception development reflected by the infant MMR.

Association of Postpartum Maternal Mood With Infant Speech Perception at 2 and 6.5 Months of Age.

Importance: Language development builds on speech perception, with early disruptions increasing the risk for later language difficulties. Although a major postpartum depressive episode is associated with language development, this association has not been investigated among infants of mothers experiencing a depressed mood at subclinical levels after birth, even though such a mood is frequently present in the first weeks after birth. Understanding whether subclinical depressed maternal mood after birth is associated with early language development is important given opportunities of coping strategies for subclinical depressed mood. Objective: To examine whether depressed maternal mood at subclinical levels 2 months after birth is associated with infant speech perception trajectories from ages 2 to 6.5 months. Design, Setting, and Participants: In this longitudinal cohort study conducted between January 1, 2018, and October 31, 2019, 46 healthy, monolingual German mother-infant dyads were tested. The sample was recruited from the infants database of the Max Planck Institute for Human Cognitive and Brain Sciences. Initial statistical analysis was performed between January 1 and March 31, 2021; the moderation analysis (results reported herein) was conducted between July 1 and July 31, 2022. Exposures: Mothers reported postpartum mood via the German version of the Edinburgh Postnatal Depression Scale (higher scores indicated higher levels of depressed mood, with a cutoff of 13 points indicating a high probability of clinical depression) when their infants were 2 months old. Main Outcomes and Measures: Electrophysiological correlates of infant speech perception (mismatch response to speech stimuli) were tested when the infants were aged 2 months (initial assessment) and 6.5 months (follow-up). Results: A total of 46 mothers (mean [SD] age, 32.1 [3.8] years) and their 2-month-old children (mean [SD] age, 9.6 [1.2] weeks; 23 girls and 23 boys) participated at the initial assessment, and 36 mothers (mean [SD] age, 32.2 [4.1] years) and their then 6.5-month-old children (mean [SD] age, 28.4 [1.5 weeks; 18 girls and 18 boys) participated at follow-up. Moderation analyses revealed that more depressed maternal subclinical postpartum mood (mean [SD] Edinburgh Postnatal Depression Scale score, 4.8 [3.6]) was associated with weaker longitudinal changes of infants' electrophysiological brain responses to syllable pitch speech information from ages 2 to 6.5 months (coefficient: 0.68; 95% CI, 0.03-1.33; P = .04). Conclusions and Relevance: The results of this cohort study suggest that infant speech perception trajectories are correlated with subclinical depressed mood in postpartum mothers. This finding lays the groundwork for future research on early support for caregivers experiencing depressed mood to have a positive association with children's language development.

Infants' vocalizations at 6 months predict their productive vocabulary at one year.

Long before their first words, children communicate by using speech-like vocalizations. These protophones might be indicative of infants' later language development. We here examined infants' (n = 56) early vocalizations at 6 months (vocal reactivity scale of the IBQ-R) as a predictor of their expressive and receptive language at 12 months (German version of the CDI). Regression analyses revealed vocalizations to significantly predict expressive, but not receptive language. Our findings in German-learning 6-month-olds extend previous predictive evidence of early vocalizations reported for older infants. Together these findings are informative in light of early assessments monitoring typical and atypical language development.

Aberrant Prestimulus Oscillations in Developmental Dyslexia Support an Underlying Attention Shifting Deficit.

Developmental dyslexia (DD) impairs reading and writing acquisition in 5-10% of children, compromising schooling, academic success, and everyday adult life. DD associates with reduced phonological skills, evident from a reduced auditory mismatch negativity (MMN) in the electroencephalogram (EEG). It was argued that such phonological deficits are secondary to an underlying deficit in the shifting of attention to upcoming speech sounds. Here, we tested whether the aberrant MMN in individuals with DD is a function of EEG correlates of prestimulus attention shifting; based on prior findings, we focused prestimulus analyses on alpha-band oscillations. We administered an audio-visual oddball paradigm to school children with and without DD. Children with DD showed EEG markers of deficient attention switching (i.e., increased prestimulus alpha-band intertrial phase coherence [ITPC]) to precede and predict their reduced MMN-aberrantly increased ITPC predicted an aberrantly reduced MMN. In interaction, ITPC and MMN predicted reading abilities, such that poor readers showed both high ITPC and a reduced MMN, the reverse being true in good readers. Prestimulus ITPC may be an overlooked biomarker of deficient attention shifting in DD. The findings support the proposal that an attention shifting deficit underlies phonological deficits in DD, entailing new opportunities for targeted intervention.

Phonemes, words, and phrases: Tracking phonological processing in pre-schoolers developing dyslexia.

OBJECTIVES: Individuals with dyslexia often suffer from deficient segmental phonology, but the status of suprasegmental phonology (prosody) is still discussed. METHODS: In three passive-listening event-related brain potential (ERP) studies, we examined prosodic processing in literacy-impaired children for various prosodic units by contrasting the processing of word-level and phrase-level prosody, alongside segmental phonology. We retrospectively analysed school children's ERPs at preschool age for discrimination of vowel length (phoneme processing), discrimination of stress pattern (word-level prosody), and processing of prosodic boundaries (phrase-level prosody). RESULTS: We found differences between pre-schoolers with and without later literacy difficulties for phoneme and stress pattern discrimination, but not for prosodic boundary perception. CONCLUSION: Our findings complement the picture of phonological processing in dyslexia by confirming difficulties in segmental phonology and showing that prosodic processing is affected for the smaller word level, but not the larger phrase level. SIGNIFICANCE: These findings might have implications for early interventions, considering both phonemic awareness and stress pattern training.

Cortical thickness lateralization and its relation to language abilities in children.

The humans' brain asymmetry is observed in the early stages of life and known to change further with age. The developmental trajectory of such an asymmetry has been observed for language, as one of the most lateralized cognitive functions. However, it remains unclear how these age-related changes in structural asymmetry are related to changes in language performance. We collected longitudinal structural magnetic resonance imaging data of children from 5 to 6 years to investigate structural asymmetry development and its linkage to the improvement of language comprehension abilities. Our results showed substantial changes of language performance across time, which were associated with changes of cortical thickness asymmetry in the triangular part of the inferior frontal gyrus (IFG), constituting a portion of Broca's area. This suggests that language improvement is influenced by larger cortical thinning in the left triangular IFG compared to the right. This asymmetry in children's brain at age 5 and 6 years was further associated with the language performance at 7 years. To our knowledge, this is the first longitudinal study to demonstrate that children's improvement in sentence comprehension seems to depend on structural asymmetry changes in the IFG, further highlighting its crucial role in language acquisition.

Children with dyslexia show a reduced processing benefit from bimodal speech information compared to their typically developing peers.

During information processing, individuals benefit from bimodally presented input, as has been demonstrated for speech perception (i.e., printed letters and speech sounds) or the perception of emotional expressions (i.e., facial expression and voice tuning). While typically developing individuals show this bimodal benefit, school children with dyslexia do not. Currently, it is unknown whether the bimodal processing deficit in dyslexia also occurs for visual-auditory speech processing that is independent of reading and spelling acquisition (i.e., no letter-sound knowledge is required). Here, we tested school children with and without spelling problems on their bimodal perception of video-recorded mouth movements pronouncing syllables. We analyzed the event-related potential Mismatch Response (MMR) to visual-auditory speech information and compared this response to the MMR to monomodal speech information (i.e., auditory-only, visual-only). We found a reduced MMR with later onset to visual-auditory speech information in children with spelling problems compared to children without spelling problems. Moreover, when comparing bimodal and monomodal speech perception, we found that children without spelling problems showed significantly larger responses in the visual-auditory experiment compared to the visual-only response, whereas children with spelling problems did not. Our results suggest that children with dyslexia exhibit general difficulties in bimodal speech perception independently of letter-speech sound knowledge, as apparent in altered bimodal speech perception and lacking benefit from bimodal information. This general deficit in children with dyslexia may underlie the previously reported reduced bimodal benefit for letter-speech sound combinations and similar findings in emotion perception.

Auditory brainstem responses to stop consonants predict literacy.

OBJECTIVE: Precise temporal coding of speech plays a pivotal role in sound processing throughout the central auditory system, which, in turn, influences literacy acquisition. The current study tests whether an electrophysiological measure of this precision predicts literacy skills. METHODS: Complex auditory brainstem responses were analysed from 62 native German-speaking children aged 11-13years. We employed the cross-phaseogram approach to compute the quality of the electrophysiological stimulus contrast [da] and [ba]. Phase shifts were expected to vary with literacy. RESULTS: Receiver operating curves demonstrated a feasible sensitivity and specificity of the electrophysiological measure. A multiple regression analysis resulted in a significant prediction of literacy by delta cross-phase as well as phonological awareness. A further commonality analysis separated a unique variance that was explained by the physiological measure, from a unique variance that was explained by the behavioral measure, and common effects of both. CONCLUSIONS: Despite multicollinearities between literacy, phonological awareness, and subcortical differentiation of stop consonants, a combined assessment of behavior and physiology strongly increases the ability to predict literacy skills. SIGNIFICANCE: The strong link between the neurophysiological signature of sound encoding and literacy outcome suggests that the delta cross-phase could indicate the risk of dyslexia and thereby complement subjective psychometric measures for early diagnoses.