Early electrophysiological markers of atypical language processing in prematurely born infants

Longstanding Auditory Sensory and Semantic Differences in Preterm Born Children

More than 10% of births are preterm, and the long-term consequences on sensory and semantic processing of non-linguistic information remain poorly understood. 17 very preterm-born children (born at < 33 weeks gestational age) and 15 full-term controls were tested at 10 years old with an auditory object recognition task, while 64-channel auditory evoked potentials (AEPs) were recorded. Sounds consisted of living (animal and human vocalizations) and manmade objects (e.g. household objects, instruments, and tools). Despite similar recognition behavior, AEPs strikingly differed between full-term and preterm children. Starting at 50ms post-stimulus onset, AEPs from preterm children differed topographically from their full-term counterparts. Over the 108-224ms post-stimulus period, full-term children showed stronger AEPs in response to living objects, whereas preterm born children showed the reverse pattern; i.e. stronger AEPs in response to manmade objects. Differential brain activity between semantic categories could reliably classify children according to their preterm status. Moreover, this opposing pattern of differential responses to semantic categories of sounds was also observed in source estimations within a network of occipital, temporal and frontal regions. This study highlights how early life experience in terms of preterm birth shapes sensory and object processing later on in life.

Listening Preference for Child-Directed Speech Versus Time-Reversed Speech in Moderate-Preterm Infants Compared to Full-Term Infants

PURPOSE

The purpose of the present study was to examine whether there is a listening preference for child-directed speech (CDS) over backward speech in moderate-preterm infants (MPIs).

METHOD

Eighteen MPIs of gestational age of 32.0 weeks (range: 32-34.06 weeks), chronological age of 8.09 months, and maturation age of 6.48 months served as the experimental group. The two control groups consisted of a total of 36 infants-20 full-term infants matched for chronological age and 16 full-term infants matched for maturation age. The infants were tested using the central fixation procedure and were presented with 16 trials of CDS and backward speech. A follow-up was conducted 5 years after the initial experiment using a developmental and a five-item parent questionnaire.

RESULTS

MPIs did not demonstrate a preference for CDS over backward speech, whereas both control groups demonstrated a listening preference for CDS over backward speech. MPIs showed a delayed use of first words and word combinations and lower scores on the five-item questionnaire compared to term infants. Twelve MPIs (67%) did not demonstrate a preference for CDS over backward speech. Four of them (33%) were later diagnosed with neurodevelopmental disorders.

CONCLUSIONS

The lack of preference for CDS over backward speech in the MPIs group suggests delayed developmental pattern of speech processing compared to full-term peers. Delays in neurological maturation as well as listening experience in an unregulated environment outside the uterus during a sensitive period of brain development may affect the recognition of phonological and prosodic patterns that support listening preference for speech over backward speech.

Adaptation and validation of the European Portuguese Communication and Symbolic Behaviour Scales Developmental Profile™ (CSBS DP™) Infant-Toddler Checklist

BACKGROUND

As delays or disorders in early language and communication are the most prevalent symptom in children with disabilities, early screening is crucial to promote prevention, early diagnosis, and intervention. However, to the best of our knowledge, no screening tool is available for the joint assessment of early language and social communication skills in European Portuguese (EP)-learning children, which is critical for screening, monitoring and enrolment in appropriate early intervention services.

AIMS

(1) To adapt and validate the EP version of the Communication and Symbolic Behaviour Scales Developmental Profile™ (CSBS DP™) Infant-Toddler Checklist, a parental report for the screening of early language and social communication skills. (2) To conduct a cross-cultural comparison between the EP adaptation and the original US version.

METHODS & PROCEDURES

A total of 611 EP-learning children (ages 6-24 months) were assessed on the CSBS DP Infant-Toddler Checklist. Normative data, psychometric characteristics (i.e., internal consistency and test-retest reliability), and cross-cultural comparison between the EP and the original version were explored.

OUTCOMES & RESULTS

Internal consistency ranged from good to excellent and the test-retest reliability was excellent. The performance of the EP and US samples matched on almost all scores. However, EP children performed significantly better than their American peers in the Social compositive at 22 months and in the Symbolic composite at 20 months. No further differences were found.

CONCLUSIONS & IMPLICATIONS

These findings showed that the EP CSBS DP Infant-Toddler Checklist seems to be a reliable screening tool of communicative and symbolic behaviours for EP-learning children, which can be particularly relevant for decision-making in clinical practice.

WHAT THIS PAPER ADDS

What is already known on the subject Early communication skills are known to be related to later language outcomes. Thus, screening tools for the early identification of children at risk for language and communication impairments, which may lead to monitoring and early intervention, have the potential to promote better outcomes. However, to the best of our knowledge, no screening tool is available for the assessment of early communication abilities in EP-learning children. What this paper adds to existing knowledge This study adapted and validated the EP CSBS DP Infant-Toddler Checklist, the first published parental report checklist for the assessment of early communication skills in EP. It described the psychometric characteristics of the adapted checklist, summarized the newly available normative data for EP-learning infants and toddlers, and compared the performance of EP-learning children with the original standardization sample reported for American English. The results demonstrated that this tool is a reliable instrument for the early screening of language, communicative and symbolic behaviours for EP-learning children between 6 and 24 months of age. What are the potential or actual clinical implications of this work? Given that early screening is crucial to promote prevention, early diagnosis and intervention, the availability of this tool is particularly relevant for children monitoring and their enrolment in appropriate early intervention services, helping decision-making in clinical practice, in line with current guidelines regarding early monitoring and intervention to promote and support better outcomes. Thus, the tool and related normative data will be useful for paediatricians, family doctors, primary healthcare providers, developmental psychologists and speech-language therapists, among other professionals in the healthcare and educational fields, concerned with speech, language, and communication development and impairments.

Maturation of the mismatch response in pre-school children: Systematic literature review and meta-analysis

Event-related potentials (ERPs), specifically the Mismatch Response (MMR), holds promise for investigating auditory maturation in children. It has the potential to predict language development and distinguish between language-impaired and typically developing groups. However, summarizing the MMR's developmental trajectory in typically developing children remains challenging despite numerous studies. This pioneering meta-analysis outlines changes in MMR amplitude among typically developing children, while offering methodological best-practices. Our search identified 51 articles for methodology analysis and 21 for meta-analysis, involving 0-8-year-old participants from 2000 to 2022. Risk of Bias assessment and methodology analysis revealed shortcomings in control condition usage and reporting of study confounders. The meta-analysis results were inconsistent, indicating large effect sizes in some conditions and no effect sizes in others. Subgroup analysis revealed the main effects of age and brain region, as well as an interaction of age and time-window of the MMR. Future research requires a specific protocol, larger samples, and replication studies to deepen the understanding of the auditory discrimination maturation process in children.

La habilidad lingüística en prematuros extremos en edad escolar

En España, el número de nacimientos prematuros es de 30.000, siendo una de las principales causas de mortalidad perinatal. En los últimos años, gracias a los avances médicos, la tasa de supervivencia de esta población se ha visto incrementada, lo cual ha evidenciado la aparición de nuevas morbilidades y comorbilidades que pueden interferir en su proceso de aprendizaje. Este estudio, de carácter cualitativo y longitudinal, cuenta con un muestreo no probabilístico por conveniencia. Su objeto es analizar la habilidad lingüística de cuatro menores grandes prematuros, con una edad gestacional al nacimiento igual o inferior a las 28 semanas, que actualmente cursan 4º de Educación Primaria, para detectar posibles dificultades en la adquisición y en el uso del lenguaje. Se les administró la Batería del Lenguaje Objetiva y Criterial Revisado (BLOC-SR) a la edad cronológica de 8 y 10 años. Los resultados sugieren que existen dificultades en la adquisición de los componentes del lenguaje: en el morfológico, por ejemplo, aparece en el uso de las formas verbales, en los sustantivos derivados, etc.; en el sintáctico, en las oraciones subordinadas de causa y condición, etc.; en el semántico se evidencian en los locativos, etc., y en el pragmático, en la realización de preguntas. A modo de conclusión, los menores prematuros extremos, debido a su condición de vulnerabilidad biológica al quedar interrumpida la maduración cerebral por su nacimiento temprano, necesitan potenciar las destrezas lingüísticas, entre las que destaca la conciencia semántica, siendo necesario diseñar propuestas de intervención para el ámbito escolar.

Impact of feeding habits on the development of language-specific processing of phonemes in brain: An event-related potentials study

Introduction

Infancy is a stage characterized by multiple brain and cognitive changes. In a short time, infants must consolidate a new brain network and develop two important properties for speech comprehension: phonemic normalization and categorical perception. Recent studies have described diet as an essential factor in normal language development, reporting that breastfed infants show an earlier brain maturity and thus a faster cognitive development. Few studies have described a long-term effect of diet on phonological perception.

Methods

To explore that effect, we compared the event-related potentials (ERPs) collected during an oddball paradigm (frequent /pa/80%, deviant/ba/20%) of infants fed with breast milk (BF), cow-milk-based formula (MF), and soy-based formula (SF), which were assessed at 3, 6, 9, 12, and 24 months of age [Mean across all age groups: 127 BF infants, Mean (M) 39.6 gestation weeks; 121 MF infants, M = 39.16 gestation weeks; 116 SF infants, M = 39.16 gestation weeks].

Results

Behavioral differences between dietary groups in acoustic comprehension were observed at 24-months of age. The BF group displayed greater scores than the MF and SF groups. In phonological discrimination task, the ERPs analyses showed that SF group had an electrophysiological pattern associated with difficulties in phonological-stimulus awareness [mismatch negativity (MMN)-2 latency in frontal left regions of interest (ROI) and longer MMN-2 latency in temporal right ROI] and less brain maturity than BF and MF groups. The SF group displayed more right-lateralized brain recruitment in phonological processing at 12-months old.

Discussion

We conclude that using soy-based formula in a prolonged and frequent manner might trigger a language development different from that observed in the BF or MF groups. The soy-based formula's composition might affect frontal left-brain area development, which is a nodal brain region in phonological-stimuli awareness.

Auditory Processing of the Brain Is Enhanced by Parental Singing for Preterm Infants

As the human auditory system is highly malleable in infancy, perinatal risk factors, such as preterm birth, may affect auditory development. In comparison to healthy full-term infants, preterm infants show abnormal auditory brain responses at term age, which may have long-term detrimental outcomes. To achieve an optimal neonatal care environment for preterm-born infants, many early interventions have been developed. Musical interventions developed for neonatal intensive care units (NICUs) have shown beneficial effects on vital functions and weight gain of preterm infants and might also influence basic auditory processing and thereby enhance outcomes. In the present study, we tested the effect of parental singing during kangaroo care on auditory processing of standardized audio stimuli. Preterm infants (born between 24 and 32 weeks of gestation) were randomized to singing intervention (n = 13) or control (n = 8) groups. The auditory processing was tested using two audio paradigms assessed with magnetoencephalography (MEG) at term corresponding age. To verify that the paradigms elicit responses in MEG, we studied 12 healthy full-term infants. In the singing intervention group, parents were instructed by a music therapist twice a week for 4 weeks to sing or hum during kangaroo care in an infant-directed way. The control group received standard kangaroo care. The results show that the infants in the singing intervention group show larger neural responses than those in the control group when controlling for the total amount of singing during kangaroo care. Our findings suggest that incorporating singing into kangaroo care may be beneficial for preterm infants, but the effect may not be due to exposure to singing but instead positive parenting, improved parental self-esteem and improved caregiver sensitivity.

Neural Speech Encoding in Infancy Predicts Future Language and Communication Difficulties

Purpose This study aimed to construct an objective and cost-effective prognostic tool to forecast the future language and communication abilities of individual infants. Method Speech-evoked electroencephalography (EEG) data were collected from 118 infants during the first year of life during the exposure to speech stimuli that differed principally in fundamental frequency. Language and communication outcomes, namely four subtests of the MacArthur-Bates Communicative Development Inventories (MCDI)-Chinese version, were collected between 3 and 16 months after initial EEG testing. In the two-way classification, children were classified into those with future MCDI scores below the 25th percentile for their age group and those above the same percentile, while the three-way classification classified them into < 25th, 25th-75th, and > 75th percentile groups. Machine learning (support vector machine classification) with cross validation was used for model construction. Statistical significance was assessed. Results Across the four MCDI measures of early gestures, later gestures, vocabulary comprehension, and vocabulary production, the areas under the receiver-operating characteristic curve of the predictive models were respectively .92 ± .031, .91 ± .028, .90 ± .035, and .89 ± .039 for the two-way classification, and .88 ± .041, .89 ± .033, .85 ± .047, and .85 ± .050 for the three-way classification (p < .01 for all models). Conclusions Future language and communication variability can be predicted by an objective EEG method that indicates the function of the auditory neural pathway foundational to spoken language development, with precision sufficient for individual predictions. Longer-term research is needed to assess predictability of categorical diagnostic status. Supplemental Material https://doi.org/10.23641/asha.15138546.

Mismatch response in preterm and asphyxic neonates: a functional electrophysiological investigation of attention and habituation

BACKGROUND AND AIM

There is a lack of diagnostic tools for early risk stratification of cognitive outcome in infants born preterm and infants with asphyxia. Using auditory event-related potentials and mismatch response, we aimed to assess possible differences in early attention and learning, as a marker for brain maturation to subsequently improve the allocation of early neurodevelopmental support.

STUDY DESIGN AND METHODS

This cross-sectional study included 22 very preterm infants (gestational age (GA) < 32 weeks), eight term infants with asphyxia and 35 healthy term infants. An auditory oddball-paradigm with three consecutive stimulation blocks, separated by a two-minute break, was used as a cognitive discrimination task to assess attention and habituation.

RESULTS

The peak-to-peak analysis in the group comparisons showed no significant differences for the first stimulation block. In term healthy infants and term infants after asphyxia, no significant differences were found in amplitudes between block one and three. Preterm infants showed significantly (p = .007) lower amplitudes in the third block for F7 congruent to a positive habituation. The amplitude of the grouped electrodes correlated positively with GA for frontal (R = .271, p= .029) and parietal electrodes (R =.275, p = .027).

CONCLUSION

We found no differences in the auditory attention paradigm between preterm or term asphyxic and control infants when they were evaluated at term corrected age. Most infants did not show any electrophysiologically measurable learning effect indicating habituation or dishabituation. The small sample size of this study is a clear limitation. Therefore, the results must be evaluated with caution, especially regarding their potential predictive value for future cognitive development of infants with a developmental risk. However, our study underlines the possibility of an electrophysiological evaluation as a feasible tool to assess very early cognition in infants.

Predictive value of electroencephalogram, event-related potential, and general movements quality assessment in neurodevelopmental outcome of high-risk infants

OBJECTIVE

The objective of the study is to investigate the predictive value of electroencephalogram (EEG), event-related potential (ERP), and general movements (GMs) quality assessment in the neurodevelopmental outcome of high-risk infants at one year old.

METHODS

EEG and ERP were performed in high-risk infants at four weeks old, and GMs quality was evaluated once at 4 weeks and once at 12 weeks. The Gesell score was used to assess neurodevelopment outcome at one year old. A comparative analysis of the effects of EEG, GMs, EEG + ERP, and EEG + ERP + GMs was used to predict high-risk neonatal neurodevelopmental outcome.

RESULTS

Of 71 high-risk infants at the age of one year, 3 (4.23%) had cerebral palsy, 14 (19.72%) had psychomotor retardation, and 54 (76.05%) were normal. The sensitivity, specificity, positive predictive value, and negative predictive value of EEG + ERP + GMs method were 90.00%, 95.08%, 75.00%, and 98.31%, respectively, and these indexes were the highest among the four methods (EEG, GMs, EEG + ERP, and EEG + ERP + GMs). The kappa statistic for the reliability of predicting neurodevelopmental outcome of high risk newborns by the EEG + ERP + GMs method was substantial at 0.785, while the other three methods obtained relatively low Kappa values (0.599, 0.586, and 0.712, respectively).

CONCLUSIONS

The combination of EEG, ERP, and GMs quality assessment can greatly improve the prediction of neurodevelopmental outcome of high-risk newborns.

Cortical auditory-evoked potential as a biomarker of central auditory maturation in term and preterm infants during the first 3 months

OBJECTIVES

To analyze central auditory maturation in term and preterm infants during the first 3 months of life by comparing the latency and amplitude of cortical auditory-evoked potential at different frequencies.

METHODS

In this study, 17 term and 18 preterm infants were examined; all had tested positive on the neonatal hearing screening test. Cortical auditory potential was investigated during the first and third months of life. The response of the cortical auditory-evoked potential was investigated at frequencies of 500, 1000, 2000, and 4000 Hz. The latency and amplitude of the cortical response were automatically detected and manually analyzed by three researchers with experience in electrophysiology. The results were compared using analysis of variance and the Bonferroni test. A significance level of 5% was used for all analyses.

RESULTS

Latency values of cortical auditory-evoked potential in the first month of birth were significantly higher than those in the third month, and latency values of the preterm group were higher than those of the term group, regardless of the frequency and time of evaluation. In general, the latency of the cortical auditory-evoked potential was higher at high frequencies. Amplitude values in the third month of life were significantly higher than those in the first month for term and preterm infants.

CONCLUSION

Central auditory maturation was observed in both groups but with different results between those born at term and preterm, with latencies of cortical auditory-evoked potential higher for the preterm group and at high frequencies.

Impact of prematurity on neurodevelopment

The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.

Uneven Linguistic Outcome in Extremely Preterm Children

One primary problem in extremely preterm children is the occurrence of atypical language development. The aim of this study was to explore the components of language (articulatory phonetics, lexicon and syntax) in comprehension and production in extremely preterm children between the 4th and 5th year of age. The language section of the Preschool Neuropsychological Test was administered to 20 extremely preterm monolingual Italian children (GA < 28 weeks) and to a control sample of 40 full term children (GA > 37 weeks), matched for age and non-verbal IQ. Language comprehension was fully efficient in all of the components that we assessed. In the tasks of language production the clinical sample fared much worse than their age and IQ matched controls and the differences were highly significant (p < .001). Language acquisition in extremely preterm children may follow uneven developmental trajectories: language comprehension can be spared in the face of a selective impairment of language production at the level of articulatory phonetics and syntax.

Amplitude-integrated electroencephalography shows alterations in children born preterm displaying poor literacy precursor skills

AIM

To assess whether amplitude-integrated electroencephalography (aEEG) alterations in the newborn period are associated with poor precursor skills of literacy at five years of age in children born preterm.

METHODS

Between October 2007 and September 2011 248 preterm infants were eligible for the study at Innsbruck Medical University Hospital. aEEG was analysed for dominating background activity, calculation of the percentage of continuous activity, the Burdjalov scoring system, the minimum, mean and maximum amplitude. At the age of five years, we evaluated preterm born children by the Bielefelder screening (BISC) to assess for early diagnosis of reading problems and weak spelling and classified them as normal performers (n = 64) or poor performers (n = 20). Completion of testing was not possible for one infant.

RESULTS

The minimum amplitude was significantly lower in the poor BISC performance group as compared to the normal BISC performance group at postnatal week two. The percentage of continuous background activity was significantly higher in infants with normal BISC performance than in infants with poor BISC performance at postnatal week three.

CONCLUSION

Children with poor developed precursor skills of literacy showed alterations in aEEG signals. The aEEG could be useful in further diagnosing preterm infants at risk for developmental complications.

Does intra-uterine language experience modulate word stress processing? An ERP study

BACKGROUND

Preterm birth is associated with various risks, including delayed or atypical language development. The prenatal start of prosodic tuning may affect the processing of word stress, an important suprasegmental feature of spoken utterances.

AIM

Our study focused on the expected contribution of intra-uterine experience to word stress processing. We aimed to demonstrate the hypothesized effect of intra-uterine sound exposition on stress sensitivity.

METHOD

We recorded ERP responses of 34 preterm infants elicited by bisyllabic pseudo-words in two oddball conditions by switching the stress pattern (legal vs. illegal) and role (standard vs. deviant).

RESULTS

The mismatch responses found were synchronized to each syllable of the illegally stressed stimuli with no difference between pre- and full-term infants. However, the clear role of the preterm status was demonstrated by the exaggerated processing of the native stress information. The impact of intra-uterine exposure to prosody was confirmed by our finding that moderate-late preterm infants outperformed the very preterm ones.

CONCLUSION

Intra-uterine exposition to prosodic features appears to contribute to the emergence of stable long-term stress representation. When this tuning is missing it is considered a risk for the language acquisition process.

Differential Rates of Perinatal Maturation of Human Primary and Nonprimary Auditory Cortex

Primary and nonprimary cerebral cortex mature along different timescales; however, the differences between the rates of maturation of primary and nonprimary cortex are unclear. Cortical maturation can be measured through changes in tissue microstructure detectable by diffusion magnetic resonance imaging (MRI). In this study, diffusion tensor imaging (DTI) was used to characterize the maturation of Heschl's gyrus (HG), which contains both primary auditory cortex (pAC) and nonprimary auditory cortex (nAC), in 90 preterm infants between 26 and 42 weeks postmenstrual age (PMA). The preterm infants were in different acoustical environments during their hospitalization: 46 in open ward beds and 44 in single rooms. A control group consisted of 15 term-born infants. Diffusion parameters revealed that (1) changes in cortical microstructure that accompany cortical maturation had largely already occurred in pAC by 28 weeks PMA, and (2) rapid changes were taking place in nAC between 26 and 42 weeks PMA. At term equivalent PMA, diffusion parameters for auditory cortex were different between preterm infants and term control infants, reflecting either delayed maturation or injury. No effect of room type was observed. For the preterm group, disturbed maturation of nonprimary (but not primary) auditory cortex was associated with poorer language performance at age two years.

Noise Equally Degrades Central Auditory Processing in 2- and 4-Year-Old Children

PURPOSE

The aim of this study was to investigate developmental and noise-induced changes in central auditory processing indexed by event-related potentials in typically developing children.

METHOD

P1, N2, and N4 responses as well as mismatch negativities (MMNs) were recorded for standard syllables and consonants, frequency, intensity, vowel, and vowel duration changes in silent and noisy conditions in the same 14 children at the ages of 2 and 4 years.

RESULTS

The P1 and N2 latencies decreased and the N2, N4, and MMN amplitudes increased with development of the children. The amplitude changes were strongest at frontal electrodes. At both ages, background noise decreased the P1 amplitude, increased the N2 amplitude, and shortened the N4 latency. The noise-induced amplitude changes of P1, N2, and N4 were strongest frontally. Furthermore, background noise degraded the MMN. At both ages, MMN was significantly elicited only by the consonant change, and at the age of 4 years, also by the vowel duration change during noise.

CONCLUSIONS

Developmental changes indexing maturation of central auditory processing were found from every response studied. Noise degraded sound encoding and echoic memory and impaired auditory discrimination at both ages. The older children were as vulnerable to the impact of noise as the younger children.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5233939.

Abnormalities in cortical auditory responses in children with central auditory processing disorder

The main objective of the present study was to identify markers of neural deficits in children with central auditory processing disorder (CAPD) by measuring latency and amplitude of the auditory cortical responses and mismatch negativity (MMN) responses. Passive oddball paradigms were used with nonverbal and verbal stimuli to record cortical auditory-evoked potentials and MMN. Twenty-three children aged 9-12 participated in the study: 10 with normal hearing acuity as well as CAPD and 13 with normal hearing without CAPD. No significant group differences were observed for P1 latency and amplitude. Children with CAPD were observed to have significant N2 latency prolongation and amplitude reduction with nonverbal and verbal stimuli compared to children without CAPD. No significant group differences were observed for the MMN conditions. Moreover, electrode position affected the results in the same manner for both groups of children. The findings of the present study suggest that the N2 response could be a marker of neural deficits in children with CAPD. N2 results suggest that maturational factors or a different mechanism could be involved in processing auditory information at the central level for these children.