Electrophysiology of Perception and Processing of Phonological Information as Indices of Toddlers' Language Performance

Event Related Potentials to Native Speech Contrasts Predicts Word Reading Abilities in Early School-Aged Children

Speech perception skills have been implicated in the development of phoneme-grapheme correspondence, yet the exact nature of speech perception and word reading ability remains unknown. We investigate phonological sensitivity to native (English) and nonnative (Spanish) speech syllables within an auditory oddball paradigm using event related potentials (ERPs) collected from lateral temporal electrode sites in 33 monolingual English-speaking children aged 6-8 years (N=33). We further explore the relationship between ERPs to English word reading abilities for this group. Results revealed that language stimuli (English, Spanish), ERP condition (standard, deviant), and hemisphere (left, right) all influenced the lateral N1 component. ERPs recorded from deviant English stimuli were significantly more negative within the left hemisphere compared to all other recorded ERPs. Mean amplitude differences within the N1 in left lateral electrode sites recorded in response to English phoneme contrasts significantly predicted English word reading abilities within this sample. Results indicate that speech perception of native contrasts recorded in left temporal electrode sites for the N1 component are linked to English word reading abilities in early school-aged children.

ERP Indicators of Phonological Awareness Development in Children: A Systematic Review

Phonological awareness is the ability to correctly recognize and manipulate phonological structures. The role of phonological awareness in reading development has become evident in behavioral research showing that it is inherently tied to measures of phonological processing and reading ability. This has also been shown with ERP research that examined how phonological processing training can benefit reading skills. However, there have not been many attempts to systematically review how phonological awareness itself is developed neurocognitively. In the present review, we screened 224 papers and systematically reviewed 40 papers that have explored phonological awareness and phonological processing using ERP methodology with both typically developing and children with reading problems. This review highlights ERP components that can be used as neurocognitive predictors of early developmental dyslexia and reading disorders in young children. Additionally, we have presented how phonological processing is developed neurocognitively throughout childhood, as well as which phonological tasks can be used to predict the development of phonological awareness prior to developing reading skills. Neurocognitive measures of early phonological processing can serve as supplemental diagnostic sources to behavioral measures of reading abilities because they show different aspects of phonological sensitivity when compared to behavioral measures.

The P300 event related potential predicts phonological working memory skills in school-aged children

The P300 event related potential (ERP) has been cited as a marker of phonological working memory (PWM); however, little is known regarding its relationship to behavioral PWM skills in early school-aged children. The current study investigates the P300 ERP recorded in response to native and non-native (English and Spanish) phoneme contrasts as a predictor of PWM skills in monolingual English-speaking first and second grade children. Thirty-three typically developing children, ages 6–9, completed a battery of phonological processing, language, and cognitive assessments. ERPs were recorded within an auditory oddball paradigm in response to both English phoneme contrasts (/ta/, /pa/) and Spanish contrasts (/t̪a/, /d̪a/). The P300 ERP recorded in response to English phoneme contrasts significantly predicted standard scores on the Nonword Repetition subtest of the Comprehensive Test of Phonological Processing, Second Edition. Spanish contrasts did not elicit a P300 response, nor were amplitude or latency values within the P300 timeframe (250–500 ms) recorded in response to Spanish contrasts related to English nonword repetition performance. This study provides further evidence that the P300 ERP in response to native phonemic contrasts indexes PWM skills, specifically nonword repetition performance, in monolingual children. Further work is necessary to determine the extent to which the P300 response to changing phonological stimuli reflects PWM skills in other populations.

Event-Related Potentials to Speech Relate to Speech Sound Production and Language in Young Children

This research was funded through the American Speech and Hearing Foundation's 2012 StudentResearch Grant in Early Childhood Language Development awarded to Vanessa Harwood as well as an anonymous generous donation to Haskins Laboratories. Electrophysiological measures of language within early childhood provide important information about neurolinguistic development. We investigated associations between amplitude and latency of the P1 and N2 event-related potential components in response to spoken pseudowords, and clinical measures of language performance within a sample of 58 typically developing children between 24 and 48 months. N2 amplitude differences between repeated and new tokens were correlated with measures of expressive and receptive language and speech sound production. Phonemic sensitivity measured by the N2 component may reflect the integrity of neural networks that are important for speech perception and production in young children.

Event-Related Potentials Elicited by Phonetic Errors Differentiate Children With Speech Sound Disorder and Typically Developing Peers

PURPOSE

A growing body of research suggests that a deficit in speech perception abilities contributes to the development of speech sound disorder (SSD). However, little work has been done to characterize the neurophysiological processes indexing speech perception deficits in this population. The primary aim of this study was to compare the neural activity underlying speech perception in young children with SSD and with typical development (TD).

METHOD

Twenty-eight children ages 4;1-6;0 (years;months) participated in this study. Event-related potentials (ERPs) were recorded while children completed a speech perception task that included phonetic (speech sound) and lexical (meaning) matches and mismatches. Groups were compared on their judgment accuracy for matches and mismatches as well as the mean amplitude of the phonological mapping negativity (PMN) and N400 ERP components.

RESULTS

Children with SSD demonstrated lower judgment accuracy across the phonetic and lexical conditions compared to peers with TD. The ERPs elicited by lexical matches and mismatches did not distinguish the groups. However, in the phonetic condition, the SSD group exhibited a more consistent left-lateralized PMN effect and a delayed N400 effect over frontal sites compared to the TD group.

CONCLUSIONS

These findings provide some of the first evidence of a delay in the neurophysiological processing of phonological information for young children with SSD compared to their peers with TD. This delay was not present for the processing of lexical information, indicating a unique difference between children with SSD and with TD related to speech perception of phonetic errors. Supplemental Material https://doi.org/10.23641/asha.16915579.

An Error Analysis of Nonword Repetition Performance in Toddlers and Young Children: Theoretical Implications and Clinical Utility

Purpose Nonword repetition has been cited as a measure of phonological working memory and continues to gain status as a clinical tool used to identify language impairment in school-age children. Less is known about nonword repetition skills in the toddler population. Method The current study presents a detailed analysis of errors by segmenting nonwords into word, syllable, and phoneme levels. Errors were also analyzed for type (e.g., addition, substitution, deletion). The Test of Early Nonword Repetition was used to measure performance in a sample of 36 typically developing children, aged 24-48 months. Clinical assessments including parent report, language sampling procedures, and standardized assessments were also administered. Results As a group, participants produced significantly more syllable errors compared to word-level errors; however, most errors were made at the phoneme level. Errors of addition were the least common error type, and no differences between substitutions or deletions were present for the entire sample. Toddlers (aged 2 years) produced more syllable-level errors compared to older children (aged 3 years). Substitution errors were positively correlated with performance on clinical measures of language, whereas deletion errors were negatively correlated with performance. Conclusion Nonword repetition performance patterns in young children may be associated with language delay or language impairment and have both clinical and theoretical relevance.