Emergence of the neural network underlying phonological processing from the prereading to the emergent reading stage: A longitudinal study

Abstract

Numerous studies have shown that phonological skills are critical for successful reading acquisition. However, how the brain network supporting phonological processing evolves and how it supports the initial course of learning to read is largely unknown. Here, for the first time, we characterized the emergence of the phonological network in 28 children over three stages (prereading, beginning reading, and emergent reading) longitudinally. Across these three time points, decreases in neural activation in the left inferior parietal cortex (LIPC) were observed during an audiovisual phonological processing task, suggesting a specialization process in response to reading instruction/experience. Furthermore, using the LIPC as the seed, a functional network consisting of the left inferior frontal, left posterior occipitotemporal, and right angular gyri was identified. The connection strength in this network co-developed with the growth of phonological skills. Moreover, children with above-average gains in phonological processing showed a significant developmental increase in connection strength in this network longitudinally, while children with below-average gains in phonological processing exhibited the opposite trajectory. Finally, the connection strength between the LIPC and the left posterior occipitotemporal cortex at the prereading level significantly predicted reading performance at the emergent reading stage. Our findings highlight the importance of the early emerging phonological network for reading development, providing direct evidence for the Interactive Specialization Theory and neurodevelopmental models of reading.

Comorbidity of reading disabilities and ADHD: Structural and functional brain characteristics

“…The first task was an adaptive go/no‐go task (Donders, ): This task has shown robust effects in previous studies in children with compared to without ADHD (Vaidya et al, ) and several studies have suggested that response inhibition is the primary deficit in ADHD (Barkley et al, ; Wodka et al, ). The second fMRI paradigm was an auditory phonological processing task: This task has been employed previously (Powers et al, ; Raschle et al, , ; Yu, Raney, et al, ; Zuk et al, ) to differentiate children with and without a familial risk of reading disabilities; furthermore, phonological processing has been shown to be one of the key deficits in children with RD (Vellutino et al, ) and is one of the best predictors for reading outcome in young children (Peterson & Pennington, ; Scarborough, ). The third task was a reading fluency task: This task has shown robust effects in differentiating children with and without RD, and reading fluency is one of the key symptoms in developmental dyslexia (Langer et al, ; see below for further details).…”

“…In order to assess whether COM children show the hypoactivation characteristically seen in children with RD within the posterior reading network (for meta‐analyses, see Martin et al, ; Richlan et al, , , ; Temple, ), we employed a traditional phonological processing task. The identical stimuli, task and procedure as previously described by Powers et al (); Raschle, Zuk, & Gaab, (); Yu, Raney, et al () were used. Briefly, this phonological processing task involved listening to two common‐object words spoken sequentially in a female or male voice while images of the objects simultaneously appeared on the screen.…”

“…Furthermore, phonological processing has been shown to be a key deficit in children with RD (Vellutino, Fletcher, Snowling, & Scanlon, ) and one of the best predictors of reading outcomes in young children (Peterson & Pennington, ; Scarborough, ). The employed task has been used successfully in previous studies (Powers, Wang, Beach, Sideridis, & Gaab, ; Raschle, Stering, Meissner, & Gaab, ; Raschle, Zuk, & Gaab, ; Yu et al, ; Zuk et al, ). Reading fluency deficits are an important symptom in older children with developmental dyslexia.…”

Neural specialization of phonological and semantic processing in young children

“…These studies have suggested that these processes engage broadly similar brain regions regardless of age group (Balsamo, Xu, Gaillard, et al, 2006; Debska et al, 2016; Kovelman et al, 2012; Paquette et al, 2015; Raschle, Zuk, & Gaab, 2012; Szaflarski et al, 2006; Youssofzadeh, Williamson, & Kadis, 2017; Yu et al, 2018). In terms of phonological awareness, only a few studies examined young children using word-level phonological auditory tasks.…”

“…However, in a study that compared school-age children with dyslexia to both chronological age typical readers and younger children (5-to 6-year-old) with a matched level of phoneme awareness performing an auditory rhyming judgment task, the dyslexic readers showed hypoactivation as compared to both control groups in the left dorsolateral prefrontal cortex (Kovelman et al, 2012). More recently, another study examined developmental changes from prereading to emergent readers, using an audiovisual first phoneme matching task (Yu et al, 2018). This study showed age-related decreased activation in the left inferior parietal cortex, along with increased connectivity between this region and the left IFG, posterior left occipito-temporal cortex, and right AG for children that showed above average gains in phonological skill.…”