The present study examined the relative role played by three cognitive processes — phonological processing, verbal working memory, syntactic awareness — in understanding the reading comprehension performance among 884 native English (L1) speakers and 284 English-as-a-Second-Language (ESL) speakers in sixth-grade (mean age: 11.43 years). The performance of both groups of speakers were comparable on measures of word reading, word reading fluency, phonological awareness, phonological decoding fluency and verbal working memory. However, the ESL speakers lagged behind L1 speakers in terms of syntactic awareness. This study also emphasizes the importance of the three cognitive processes in establishing a common model of reading comprehension across English L1 and ESL reading.

Magnetic resonance imaging (MRI) provides a means to non-invasively investigate the neurological links with dyslexia, a learning disability that affects one's ability to read. Most previous brain MRI studies of dyslexia and reading skill have used structural or diffusion imaging to reveal regional brain abnormalities. However, volumetric and diffusion MRI lack specificity in their interpretation at the microstructural level. Myelin is a critical neural component for brain function and plasticity, and as such, deficits in myelin may impact reading ability. MRI can estimate myelin using myelin water fraction (MWF) imaging, which is based on evaluation of the proportion of short T2 myelin-associated water from multiexponential T2 relaxation analysis, but has not yet been applied to the study of reading or dyslexia. In this study, MWF MRI, intelligence, and reading assessments were acquired in 20 participants aged 10-18 years with a wide range of reading ability to investigate the relationship between reading ability and myelination. Group comparisons showed markedly lower MWF by 16-69% in poor readers relative to good readers in the left and right thalamus, as well as the left posterior limb of the internal capsule, left/right anterior limb of the internal capsule, left/right centrum semiovale, and splenium of the corpus callosum. MWF over the entire group also correlated positively with three different reading scores in the bilateral thalamus as well as white matter, including the splenium of the corpus callosum, left posterior limb of the internal capsule, left anterior limb of the internal capsule, and left centrum semiovale. MWF imaging from T2 relaxation suggests that myelination, particularly in the bilateral thalamus, splenium, and left hemisphere white matter, plays a role in reading abilities. Myelin water imaging thus provides a potentially valuable in vivo imaging tool for the study of dyslexia and its remediation.

This study was conducted to verify, prospectively, the ability of an anatomical risk index (ARI) constructed from seven anatomical measures of cerebral volume and perisylvian asymmetry to predict reading ability in 43 children aged 9 to 18. We found that negative ARIs (low cerebral volume and symmetry) were associated with poor reading ability only in children with low processing speed. Regression analysis showed that anatomy, speed, and an interaction term predicted 53% of the variance in real word reading (p < .0001). Leftward perisylvian asymmetry and larger cerebral volumes may support cognitive flexibility in children with low processing speed.

Dichotic pitch perception reflects the auditory system's use of binaural cues to perceptually separate different sound sources and to determine the spatial location of sounds. Several studies were conducted to identify factors that influence children's dichotic pitch perception thresholds. An initial study of school children revealed an age-related improvement in thresholds for lateralizing dichotic pitch tones. In subsequent studies potential sensory and nonsensory limitations on young children's performance of dichotic pitch lateralization tasks were examined. A training study showed that with sufficient practice, young children lateralize dichotic pitch stimuli as well as adults, indicating an age difference in perceptual learning of the lateralization task. Changing the task requirements so that young children made a judgment about the pitch of dichotic pitch tones, rather than the spatial location of the tones, also resulted in significantly better thresholds. These findings indicate that nonsensory factors limit young children's performance of dichotic pitch tasks.

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