The neural basis of phonological awareness and word reading skills

The phonological processing brain areas (i.e., the left STG and dIFG) during an auditory phonological awareness task scaffold word-reading skills in children aged 5 to 7 and 7 to 9 years old.

Citations: Wang et al. 2020 in NeuroImage (see original paper); Wang et al., 2021 in NeuroImage (see original paper).

Findings:

• Using a longitudinal design, we examined brain activation within the top 100 activated voxels in the left superior temporal gyrus (STG) and dorsal inferior frontal gyrus (dIFG) during an auditory phonological awareness task at two time points (T1 and T2). Children’s word-reading skills were assessed using the Woodcock-Johnson Word Identification test. Regression analyses revealed that, in the 5–7-year-old cohort, earlier activation in the left STG—but not the IFG—during both phonemic and rhyme processing positively predicted later word-reading skills, even after controlling for nonverbal IQ and T1 word-reading ability. In contrast, in the 7–9-year-old cohort, only earlier functional connectivity between the left dIFG and STG during rhyme processing positively predicted subsequent word-reading skills. These findings provide neural evidence that phonological processing scaffolds later word-reading development from kindergarten to early elementary school. The shift in scaffolding effects—from temporal to frontal regions—suggests a developmental transition from reliance on phonological representations to phonological access and control. Similarly, the shift from phonemic to rhyme processing indicates increasing reliance on larger phonological grain sizes during reading acquisition.

Educational or practical implications:

• When training kindergarteners with phonological processing, teachers should focus earlier on high-quality spoken word exposure to improve phonological representation and then emphasize the meta-linguistic manipulations of them to improve the efficiency of phonological access. Additionally, earlier in development, teachers should emphasize the phonemes to help a child decode words. While later in development, they should explicitly point out the rhyming structures to help a child decode words using more efficient multi-letter-to-phonology mapping.

Earlier word-reading skills also refine phonological processing brain areas (i.e., the left STG and dIFG) during an auditory phonological awareness task in children aged 5 to 7 and 7 to 9 years old.

Citations: Wang et al., 2021 in NeuroImage (see original paper); Wang et al., 2023 in Brain and Language (see original paper).

Findings:

• Using a longitudinal design, we also examined how earlier word-reading skills predicted subsequent brain decoding accuracy in the top 250 activated voxels within the left superior temporal gyrus (STG) and brain activation intensity in the top 100 activated voxels within the dorsal inferior frontal gyrus (dIFG) during an auditory phonological awareness task. Regression analyses revealed that, in the 5–7-year-old cohort, earlier word-reading skills positively predicted later brain decoding accuracy in the left STG for phonemic—but not rhyme—processing, suggesting more precise phonological representations. In contrast, in the 7–9-year-old cohort, higher earlier word-reading skills were associated with reduced later activation in the left dIFG for phonemic—but not rhyme—processing, suggesting greater neural efficiency or reduced effort. Together, these findings indicate that word-reading acquisition continues to refine phonemic processing during spoken word tasks across early childhood, from kindergarten through third grade. The developmental shift in the refinement effect—from temporal to frontal regions—again reflects a transition from fine-tuning phonological representations to optimizing phonological access and control.

Educational or practical implications:

• When using phonological processing skills as a screener in kindergarten to identify children at risk for dyslexia, it is important to recognize that word-reading experience itself can refine phonological processing, even during purely spoken word tasks. Thus, low phonological processing performance may reflect a consequence rather than a cause of poor reading performance. This consideration is particularly critical for early identification in children from lower socioeconomic backgrounds, who often have fewer literacy experiences prior to formal schooling.

Word-reading skills are associated with engagement of the left ventral occipitotemporal cortex (vOT), an orthographic representational region, during an auditory phonological awareness task in children aged 5 and 7 years old.

Citations: Wang et al., 2018 in DCN (see original paper); Wang et al., 2021 in DCN (see original paper); Wang et al., 2023 in JSLHR (see original paper).

Findings:

• Using a longitudinal design, we also examined how earlier word-reading skills predicted subsequent brain decoding accuracy in the top 250 activated voxels within the left superior temporal gyrus (STG) and brain activation intensity in the top 100 activated voxels within the dorsal inferior frontal gyrus (dIFG) during an auditory phonological awareness task. Regression analyses revealed that, in the 5–7-year-old cohort, earlier word-reading skills positively predicted later brain decoding accuracy in the left STG for phonemic—but not rhyme—processing, suggesting more precise phonological representations. In contrast, in the 7–9-year-old cohort, higher earlier word-reading skills were associated with reduced later activation in the left dIFG for phonemic—but not rhyme—processing, suggesting greater neural efficiency or reduced effort. Together, these findings indicate that word-reading acquisition continues to refine phonemic processing during spoken word tasks across early childhood, from kindergarten through third grade. The developmental shift in the refinement effect—from temporal to frontal regions—again reflects a transition from fine-tuning phonological representations to optimizing phonological access and control.

Educational or practical implications:

• For teachers who aim to improve children’s phonological awareness, providing both visual (orthographic) and auditory (phonological) information would enhance learning, as higher-skill readers’ brains are automatically wired together between the two, even for purely spoken word processing.

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