Phonological skills and learning to read

Impact of Learning to Read in a Mixed Approach on Neural Tuning to Words in Beginning Readers

The impact of learning to read in a mixed approach using both the global and phonics teaching methods on the emergence of left hemisphere neural specialization for word recognition is yet unknown in children. Taking advantage of a natural school context with such a mixed approach, we tested 42 first graders behaviorally and with Fast Periodic Visual Stimulation using electroencephalographic recordings (FPVS-EEG) to measure selective neural responses to letter strings. Letter strings were inserted periodically (1/5) in pseudofonts in 40 s sequences displayed at 6 Hz and were either words globally taught at school, that could therefore be processed by visual whole-word form recognition (global method), or control words/pseudowords eliciting grapheme-phoneme (GP) mappings (phonics method). Results show that selective responses (F/5, 1.2 Hz) were left lateralized for control stimuli that triggered GP mappings but bilateral for globally taught words. It implies that neural mechanisms recruited during visual word processing are influenced by the nature of the mapping between written and spoken word forms. GP mappings induce left hemisphere discrimination responses, and visual recognition of whole-word forms induce bilateral responses, probably because the right hemisphere is relatively more involved in holistic visual object recognition. Splitting the group as a function of the mastery of GP mappings into "good" and "poor" readers strongly suggests that good readers actually processed all stimuli (including global words) predominantly with their left hemisphere, while poor readers showed bilateral responses for global words. These results show that in a mixed approach of teaching to read, global method instruction may induce neural processes that differ from those specialized for reading in the left hemisphere. Furthermore, given their difficulties in automatizing GP mappings, poor readers are especially prone to rely on this alternative visual strategy. A preprint of this paper has been released on Biorxiv (van de Walle de Ghelcke et al., 2018).

Neural basis of the crossmodal correspondence between auditory pitch and visuospatial elevation

Crossmodal correspondences refer to associations between otherwise unrelated stimulus features in different sensory modalities. For example, high and low auditory pitches are associated with high and low visuospatial elevation, respectively. The neural mechanisms underlying crossmodal correspondences are currently unknown. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural basis of the pitch-elevation correspondence. Pitch-elevation congruency effects were observed bilaterally in the inferior frontal and insular cortex, the right frontal eye field and right inferior parietal cortex. Independent functional localizers failed to provide strong evidence for any of three proposed mechanisms for crossmodal correspondences: semantic mediation, magnitude estimation, and multisensory integration. Instead, pitch-elevation congruency effects overlapped with areas selective for visually presented non-word strings relative to sentences, and with regions sensitive to audiovisual asynchrony. Taken together with the prior literature, the observed congruency effects are most consistent with mediation by multisensory attention.

The brain adapts to orthography with experience: evidence from English and Chinese

Using functional magnetic resonance imaging (fMRI), we examined the process of language specialization in the brain by comparing developmental changes in two contrastive orthographies: Chinese and English. In a visual word rhyming judgment task, we found a significant interaction between age and language in left inferior parietal lobule and left superior temporal gyrus, which was due to greater developmental increases in English than in Chinese. Moreover, we found that higher skill only in English children was correlated with greater activation in left inferior parietal lobule. These findings suggest that the regions associated with phonological processing are essential in English reading development. We also found greater developmental increases in English than in Chinese in left inferior temporal gyrus, suggesting refinement of this region for fine-grained word form recognition. In contrast, greater developmental increases in Chinese than in English were found in right middle occipital gyrus, suggesting the importance of holistic visual-orthographic analysis in Chinese reading acquisition. Our results suggest that the brain adapts to the special features of the orthography by engaging relevant brain regions to a greater degree over development.

fMRI reveals lateralized pattern of brain activity modulated by the metrics of stimuli during auditory rhyme processing

Our fMRI study investigates auditory rhyme processing in spoken language to further elucidate the topic of functional lateralization of language processing. During scanning, 14 subjects listened to four different types of versed word strings and subsequently performed either a rhyme or a meter detection task. Our results show lateralization to auditory-related temporal regions in the right hemisphere irrespective of task. As for the left hemisphere we report responses in the supramarginal gyrus as well as in the opercular part of the inferior frontal gyrus modulated by the presence of regular meter and rhyme. The interaction of rhyme and meter was associated with increased involvement of the superior temporal sulcus and the putamen of the right hemisphere. Overall, these findings support the notion of right-hemispheric specialization for suprasegmental analyses during processing of spoken sentences and provide neuroimaging evidence for the influence of metrics on auditory rhyme processing.

Word reading skill predicts anticipation of upcoming spoken language input: a study of children developing proficiency in reading

Despite the efficiency with which language users typically process spoken language, a growing body of research finds substantial individual differences in both the speed and accuracy of spoken language processing potentially attributable to participants' literacy skills. Against this background, the current study took a look at the role of word reading skill in listeners' anticipation of upcoming spoken language input in children at the cusp of learning to read; if reading skills affect predictive language processing, then children at this stage of literacy acquisition should be most susceptible to the effects of reading skills on spoken language processing. We tested 8-year-olds on their prediction of upcoming spoken language input in an eye-tracking task. Although children, like in previous studies to date, were successfully able to anticipate upcoming spoken language input, there was a strong positive correlation between children's word reading skills (but not their pseudo-word reading and meta-phonological awareness or their spoken word recognition skills) and their prediction skills. We suggest that these findings are most compatible with the notion that the process of learning orthographic representations during reading acquisition sharpens pre-existing lexical representations, which in turn also supports anticipation of upcoming spoken words.

Attentional focus during learning impacts N170 ERP responses to an artificial script

Reading instruction can direct attention to different unit sizes in print-to-speech mapping, ranging from grapheme-phoneme to whole-word relationships. Thus, attentional focus during learning might influence brain mechanisms recruited during reading, as indexed by the N170 response to visual words. To test this, two groups of adults were trained to read an artificial script under instructions directing attention to grapheme-phoneme versus whole-word associations. N170 responses were subsequently contrasted within an active reading task. Grapheme-phoneme focus drove a left-lateralized N170 response relative to the right-lateralized N170 under whole-word focus. These findings suggest a key role for attentional focus in early reading acquisition.

ERP Nonword Rhyming Effects in Children and Adults

In a simple prime–target auditory rhyming event-related potential (ERP) paradigm with adults and 6-, 7-, and 8-year-old children, nonword stimuli (e.g., nin–rin, ked–voo) were used to investigate neurocognitive systems involved in rhyming and their development across the early school years. Even absent semantic content, the typical CNV to primes and late rhyming effect (RE) to targets were evident in all age groups. The RE consisted of a more negative response to nonrhyming targets as compared to rhyming targets over posterior sites, with a reversal of this pattern at lateral anterior sites. The hypothesis that the CNV indexes phonological memory processes was not well supported by correlation analyses conducted with the ERP measures and scores on standardized behavioral tests. However, the onset of the rhyming effect was later in those scoring lower on phonological awareness measures.

Update on the language disorders of individuals on the autistic spectrum

Inadequate language is a defining feature of the autism spectrum disorders (autism). Autism is a behaviorally and dimensionally defined developmental disorder of the immature brain that has a broad range of severity and many etiologies, with multiple genes involved. Early studies, which focused on the language of verbal children on the autistic spectrum, emphasized aberrant features of their speech such as unusual word choices, pronoun reversal, echolalia, incoherent discourse, unresponsiveness to questions, aberrant prosody, and lack of drive to communicate. Persistent lack of speech of some individuals was attributed to the severity of their autism and attendant mental retardation rather than possible inability to decode auditory language. Clinical study of unselected children with autism indicated that the language deficits of preschoolers fall into two broad types, perhaps with subtypes, those that involve reception and production of phonology (sounds of speech) and syntax (grammar), and those that do not but involve semantics (meaning) and pragmatics (communicative use of language, processing, and production of discourse). Except for the preschoolers' universally deficient pragmatics and comprehension of speech, many of their language deficits parallel those of non-autistic preschoolers with developmental language disorders. There is now biological support for the clinical observation that young autistic children are language disordered as well as autistic. Recent electrophysiological studies disclose auditory input abnormalities in lateral temporal cortex even in verbal individuals on the autistic spectrum. Severe receptive deficits for phonology enhance the risk for epilepsy. Genetic studies indicate that linkage to chromosome 7q31-33 is limited to families with evidence for phonologic impairment as well as autism. Clearly, social and cognitive disorders alone provide an inadequate explanation for the range of language deficits in autism.

Crossmodal temporal order and processing acuity in developmentally dyslexic young adults

We investigated crossmodal temporal performance in processing rapid sequential nonlinguistic events in developmentally dyslexic young adults (ages 20-36 years) and an age- and IQ-matched control group in audiotactile, visuotactile, and audiovisual combinations. Two methods were used for estimating 84% correct temporal acuity thresholds: temporal order judgment (TOJ) and temporal processing acuity (TPA). TPA requires phase difference detection: the judgment of simultaneity/nonsimultaneity of brief stimuli in two parallel, spatially separate triplets. The dyslexic readers' average temporal performance was somewhat poorer in all six comparisons; in audiovisual comparisons the group differences were not statistically significant, however. A principal component analysis indicated that temporal acuity and phonological awareness are related in dyslexic readers. The impairment of temporal input processing seems to be a general correlative feature of dyslexia in children and adults, but the overlap in performance between dyslexic and normal readers suggests that it is not a sufficient reason for developmental reading difficulties.