Letters Rhyme: Electrophysiological Evidence From Children and Adults

Language Experience Modulates the Visual N200 Response for Disyllabic Chinese Words: An Event-Related Potential Study

Prior event-related potential (ERP) research on how the brain processes non-alphabetic scripts like Chinese has identified an N200 component related to early visual processing of Chinese disyllabic words. An enhanced N200 response was observed when similar prime-target pairs were presented, but it was not elicited when native Chinese speakers read Korean Hangul, a script resembling Chinese characters. This led to the proposal that N200 was not a universal marker for orthographic processing but rather specific and unique to Chinese. However, there was uncertainty due to the absence of Korean participants in the previous research. The impact of language experience on N200 remains unclear. To address this, the present pilot ERP study included three adult groups (totaling 30 participants) with varying language proficiency levels. The participants judged if randomly presented words were Chinese or Korean, while the ERP responses were recorded. The behavioral data showed high accuracy across the groups. The reaction times differed between the groups with the native speakers responding faster. The N200 patterns varied across the groups. Both Chinese native speakers and Chinese-as-second-language learners showed stronger N200 responses for Chinese words compared to Korean words regardless of whether an adaptive or a fixed-time window was used for the N200 quantification, but this was not the case for Korean native speakers. Our cross-linguistic study suggests that N200 is not exclusive to Chinese orthography. Instead, it reflects general visual processing sensitive to both orthographic features and learning experience.

Auditory pseudoword rhyming effects in bilingual children reflect second language proficiency: An ERP study

This study investigated second language (L2-English) phonological processing in 31 Spanish-English bilingual, 6- to 8-year-old schoolchildren in an event-related potential (ERP) auditory pseudoword rhyming paradigm. In addition, associations between ERP effects and L2 proficiency as measured by standardized tests of receptive language and receptive vocabulary were explored. We found a classic posterior ERP rhyming effect that was more widely distributed in children with higher L2 proficiency in group analyses and was larger for children with better L2 proficiency in correlation analyses. In contrast, the amplitude of an early (75-125 ms) auditory positivity was larger in children with lower L2 proficiency. This pattern suggests differential use of early and late auditory/phonological processing resources in the pseudoword rhyme task associated with L2 proficiency, which is consistent with the predictions of the lexical restructuring model in a bilingual context.

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.

Uncoupled Brain and Behavior Changes in Lexical, Phonological, and Memory Processing in Struggling Readers

Paired behavioral and ERP measures were used to track change over time in 17 third- and fourth-grade struggling readers. Word and nonword reading on standardized tests improved, but differentiation of words and letter strings, measured by N170 and N400 amplitude, did not significantly change. Sound awareness scores improved, but the ERP rhyming effect did not significantly change. Both digit span scores and latency of the P300 oddball effect decreased. Correlations between the ostensibly matched behavioral and electrophysiological measures of change were not significant, indicating that use of ERP and behavioral measures can provide nonoverlapping insight into change during reading development.

A Picture Is Worth… Both Spelling and Sound

In an event-related potential (ERP) study using picture stimuli, we explored whether spelling information is co-activated with sound information even when neither type of information is explicitly provided. Pairs of picture stimuli presented in a rhyming paradigm were varied by both phonology (the two images in a pair had either rhyming, e.g., boat and goat, or non-rhyming, e.g., boat and cane, labels) and orthography (rhyming image pairs had labels that were either spelled the same, e.g., boat and goat, or not spelled the same, e.g., brain and cane). Electrophysiological picture rhyming (sound) effects were evident in terms of both N400/N450 and late effect amplitude: Non-rhyming images elicited more negative waves than rhyming images. Remarkably, the magnitude of the late ERP rhyming effect was modulated by spelling - even though words were neither explicitly seen nor heard during the task. Moreover, both the N400/N450 and late rhyming effects in the spelled-the-same (orthographically matched) condition were larger in the group with higher scores (by median split) on a standardized measure of sound awareness. Overall, the findings show concomitant meaning (semantic), sound (phonological), and spelling (orthographic) activation for picture processing in a rhyming paradigm, especially in young adults with better reading skills. Not outwardly lexical but nonetheless modulated by reading skill, electrophysiological picture rhyming effects may be useful for exploring co-activation in children with dyslexia.

Anterior and posterior erp rhyming effects in 3- to 5-year-old children

During early literacy skills development, rhyming is an important indicator of the phonological precursors required for reading. To determine if neural signatures of rhyming are apparent in early childhood, we recorded event-related potentials (ERPs) from 3- to 5-year-old, preliterate children (N = 62) in an auditory prime-target nonword rhyming paradigm (e.g., bly-gry, blane-vox). Overall, nonrhyming targets elicited a larger negativity (N450) than rhyming targets over posterior regions. In contrast, rhyming targets elicited a larger negativity than nonrhyming targets over fronto-lateral sites. The amplitude of the two rhyming effects was correlated, such that a larger posterior effect occurred with a smaller anterior effect. To determine whether these neural signatures of rhyming related to phonological awareness, we divided the children into two groups based on phonological awareness scores while controlling for age and socioeconomic status. The posterior rhyming effect was stronger and more widely distributed in the group with better phonological awareness, whereas differences between groups for the anterior effect were small and not significant. This pattern of results suggests that the rhyme processes indexed by the anterior effect are developmental precursors to those indexed by the posterior effect. Overall, these findings demonstrate early establishment of distributed neurocognitive networks for rhyme processing.

The N400 and the fourth grade shift

While behavioral and educational data characterize a fourth grade shift in reading development, neuroscience evidence is relatively lacking. We used the N400 component of the event-related potential waveform to investigate the development of single word processing across the upper elementary years, in comparison to adult readers. We presented third graders, fourth graders, fifth graders, and college students with a well-controlled list of real words, pseudowords, letter strings, false font strings, and animal name targets. Words and pseudowords elicited similar N400s across groups. False font strings elicited N400s similar to words and letter strings in the three groups of children, but not in college students. The pattern of findings suggests relatively adult-like semantic and phonological processing by third grade, but a long developmental time course, beyond fifth grade, for orthographic processing in this context. Thus, the amplitude of the N400 elicited by various word-like stimuli does not reflect some sort of shift or discontinuity in word processing around the fourth grade. However, the results do suggest different developmental time courses for the processes that contribute to automatic single word reading and the integrative N400.

Language nonselective lexical access in bilingual toddlers

We examined how words from bilingual toddlers' second language (L2) primed recognition of related target words in their first language (L1). On critical trials, prime-target word pairs were either (a) phonologically related, with L2 primes overlapped phonologically with L1 target words [e.g., slide (L2 prime)-Kleid (L1 target, "dress")], or (b) phonologically related through translation, with L1 translations of L2 primes rhymed with the L1 target words [e.g., leg (L2 prime, L1 translation, "Bein")-Stein (L1 target, "stone"). Evidence of facilitated target recognition in the phonological priming condition suggests language nonselective access but not necessarily lexical access. However, a late interference effect on target recognition in the phonological priming through translation condition provides evidence for language nonselective lexical access: The L2 prime (leg) could influence L1 target recognition (Stein) in this condition only if both the L2 prime (leg) and its L1 translation ("Bein") were concurrently activated. In addition, age- and gender-matched monolingual toddler controls showed no difference between conditions, providing further evidence that the results with bilingual toddlers were driven by cross-language activation. The current study, therefore, presents the first-ever evidence of cross-talk between the two languages of bilinguals even as they begin to acquire fluency in their second language.

Right and left perisylvian cortex and left inferior frontal cortex mediate sentence-level rhyme detection in spoken language as revealed by sparse fMRI

In this study, we used functional magnetic resonance imaging to investigate the neural basis of auditory rhyme processing at the sentence level in healthy adults. In an explicit rhyme detection task, participants were required to decide whether the ending syllable of a metrically spoken pseudosentence rhymed or not. Participants performing this task revealed bilateral activation in posterior-superior temporal gyri with a much more extended cluster of activation in the right hemisphere. These findings suggest that the right hemisphere primarily supports suprasegmental tasks, such as the segmentation of speech into syllables; thus, our findings are in line with the "asymmetric sampling in time" model suggested by Poeppel (: Speech Commun 41:245-255). The direct contrast between rhymed and nonrhymed trials revealed a stronger BOLD response for rhymed trials in the frontal operculum and the anterior insula of the left hemisphere. Our results suggest an involvement of these frontal regions not only in articulatory rehearsal processes, but especially in the detection of a matching syllable, as well as in the execution of rhyme judgment.