Auditory Phonological Task Research Articles

Neural substrates of L2-L1 transfer effects on phonological awareness in young Chinese-English bilingual children

The growing trend of bilingual education between Chinese and English has contributed to a rise in the number of early bilingual children, who were exposed to L2 prior to formal language instruction of L1. The L2-L1 transfer effect in an L1-dominant environment has been well established. However, the threshold of L2 proficiency at which such transfer manifests remains unclear. This study investigated the behavioral and neural processes involved when manipulating phonemes in an auditory phonological task to uncover the transfer effect in young bilingual children. Sixty-two first graders from elementary schools in Taiwan were recruited in this study (29 Chinese monolinguals, 33 Chinese-English bilinguals). The brain activity was measured using fNIRS (functional near-infrared spectroscopy). Bilingual children showed right lateralization to process Chinese and left lateralization to process English, which supports more on the accommodation effect within the framework of the assimilation-accommodation hypothesis. Also, compared to monolinguals, bilingual children showed more bilateral frontal activation in Chinese, potentially reflecting a mixed influence from L2-L1 transfer effects and increased cognitive load of bilingual exposure. These results elucidate the developmental adjustments in the neural substrates associated with early bilingual exposure in phonological processing, offering valuable insights into the bilingual learning process.

Learning to Read Strengthens Functional Connectivity Between the Ventral Occipitotemporal Cortex and the Superior Temporal Gyrus During an Auditory Phonological Awareness Task.

It is often assumed that phonological awareness only reflects children's phonological skill. However, orthographic representations have been found to be automatically involved during phonological awareness tasks, which we refer to as automatic orthographic activation. Although previous longitudinal neural studies have addressed how phonological processing during phonological awareness tasks is bidirectionally related to reading skill in developing children, we do not know how automatic orthographic activation plays a role in reading skill. To address this gap, we measured 40 children's reading skill and brain activity during an auditory phonological task at two time points using functional magnetic resonance imaging. Children were 5.5 to 6.5 years old at the first time point and were followed up approximately 1.5 years later when they were 7 to 8 years old. We found that earlier reading skill predicted children's later functional connectivity during onset processing between the left superior temporal gyrus, a phonological region, and the left posterior ventral occipitotemporal cortex, an orthographic region representing letters. This finding, together with previous studies, suggests that learning to read influences phonological awareness not only by refining phonological representations but also via strengthening the automatic mapping between phonemes and letters during spoken language processing.

Letter fluency in 7-8-year-old children is related to the anterior, but not posterior, ventral occipito-temporal cortex during an auditory phonological task

Previous studies have shown that reading skill in 3- to 6-year-old children is related to the automatic activation of the posterior left ventral occipitotemporal cortex (vOT) during spoken language processing, whereas 8- to 15-year-old children and adult readers activate the anterior vOT. However, it is unknown how children who are between these two age groups automatically activate orthographic representations in vOT for spoken language. In the current study, we recruited 153 7- to 8-year-old children to fill the age gap from previous studies. Using functional magnetic resonance imaging (fMRI), we measured children’s reading-related skills and brain activity during an auditory phonological task with both a small (i.e. onset) and a large (i.e. rhyme) grain size condition. We found that letter fluency, but not reading accuracy, was correlated with activation in the anterior vOT for the rhyme condition. There were no reading-related skill correlations for the posterior vOT or for activation during the onset condition in this age group. Our findings reveal that automatic activation in the anterior vOT during spoken language processing already occurs in higher skilled 7- to 8-year-old children. In addition, increases in naming automaticity is the primary determinant of the engagement of vOT during phonological awareness tasks.

Neural representations of phonology in temporal cortex scaffold longitudinal reading gains in 5- to 7-year-old children

The objective of this study was to investigate whether phonological processes measured through brain activation are crucial for the development of reading skill (i.e. scaffolding hypothesis) and/or whether learning to read words fine-tunes phonology in the brain (i.e. refinement hypothesis). We specifically looked at how different grain sizes in two brain regions implicated in phonological processing played a role in this bidirectional relation. According to the dual-stream model of speech processing and previous empirical studies, the posterior superior temporal gyrus (STG) appears to be a perceptual region associated with phonological representations, whereas the dorsal inferior frontal gyrus (IFG) appears to be an articulatory region that accesses phonological representations in STG during more difficult tasks. 36 children completed a reading test outside the scanner and an auditory phonological task which included both small (i.e. onset) and large (i.e. rhyme) grain size conditions inside the scanner when they were 5.5–6.5 years old (Time 1) and once again approximately 1.5 years later (Time 2). To study the scaffolding hypothesis, a regression analysis was carried out by entering brain activation in either STG or IFG for either small (onset > perceptual) or large (rhyme > perceptual) grain size phonological processing at T1 as the predictors and reading skill at T2 as the dependent measure, with several covariates of no interest included. To study the refinement hypothesis, the regression analysis included reading skill at T1 as the predictor and brain activation in either STG or IFG for either small or large grain size phonological processing at T2 as the dependent measures, with several covariates of no interest included. We found that only posterior STG, regardless of grain size, was predictive of reading gains. Parallel models with only behavioral accuracy were not significant. Taken together, our results suggest that the representational quality of phonology in temporal cortex is crucial for reading development. Moreover, our study provides neural evidence supporting the scaffolding hypothesis, suggesting that brain measures of phonology could be helpful in early identification of reading difficulties.

Electrophysiological registration of phonological perception in the subthalamic nucleus of patients with Parkinson’s Disease

Phonological processing is usually associated with the activation of cortical areas, especially in the left cerebral hemisphere. This study examined if phonologically elicited evoked potentials can be recorded directly from the subthalamic nucleus in patients with Parkinson’s Disease (PD). Seven PD patients who had undergone implantation of deep brain electrodes for the stimulation of the subthalamic nucleus were included. Local field potentials were recorded in a pre-attentive auditory phonological task, an attentive auditory phonological discrimination task, and a word recognition task. Auditory evoked potentials related to phonological, but not lexical processing, could be demonstrated in the subthalamic nucleus for all three tasks. Only minor changes were found after levodopa administration.This study demonstrates that the subthalamic nucleus is involved in early phonological perception, which puts the subthalamic nucleus in a position to modify phonological perception in a larger cortico-subcortical network.

A study of reading disability using event‐related brain potentials elicited during auditory alliteration judgments

Sixteen adolescent dyslexics (age range =12–18 years) and 16 similarly aged normal readers listened to spoken words and judged whether word pairs started with the same or different sounds (e.g., alliterated). Single‐syllable, high‐frequency, real‐word digitized speech stimuli were used with word pairs having a 50% chance of alliterating. Response accuracy, response latency, and event‐related brain potentials (ERPs) were recorded. Reading‐disabled participants were split into 2 groups based on performance on an auditory phonological task (Bradley Oddity Task). The 10 dyslexic participants who made errors on the task were called dysphonetics. The 6 dyslexics who made no errors were called phonetics. Normal readers responded both more accurately and faster than either reading‐disabled group. The phonetic and dysphonetic groups did not differ in accuracy or response latency. ERPs of the normal readers showed an N400 priming effect for alliterating targets. Specifically, the ERPs to the alliterating targets were significantly less negative than the ERPs to the nonalliterating targets from 250 to 450 msec post‐target onset. This effect was widely distributed bilaterally across the scalp and reached its peak over posterior sites (temporal‐central‐parietal [TCP], parietal, and occipital). The phonetic group did show a similar priming effect on the N400 for this period but only over TCP sites. The dysphonetic group did not present any priming during the 250 to 450 msec period; however, the dysphonetics did show significant priming over posterior sites between 450 and 550 msec post‐target onset. The results provide ERP evidence of abnormal phonological functioning and processing speed deficits during auditory phonological processing in reading‐disabled participants.