The influences and outcomes of phonological awareness: a study of MA, PA and auditory processing in pre-readers with a family risk of dyslexia

The direct influence of phonological awareness (PA) on reading outcomes has been widely demonstrated, yet PA may also exert indirect influence on reading outcomes through other cognitive variables such as morphological awareness (MA). However, PA's own development is dependent and influenced by many extraneous variables such as auditory processing, which could ultimately impact reading outcomes. In a group of pre-reading children with a family risk of dyslexia and low-risk controls, this study sets out to answer questions surrounding PA's relationship at various grain sizes (syllable, onset/rime and phoneme) with measures of auditory processing (frequency modulation (FM) and an amplitude rise-time task (RT)) and MA, independent of reading experience. Group analysis revealed significant differences between high- and low-risk children on measures of MA, and PA at all grain sizes, while a trend for lower RT thresholds of high-risk children was found compared with controls. Correlational analysis demonstrated that MA is related to the composite PA score and syllable awareness. Group differences on MA and PA were re-examined including PA and MA, respectively, as control variables. Results exposed PA as a relevant component of MA, independent of reading experience

Generalization of auditory sensory and cognitive learning in typically developing children

Despite the well-established involvement of both sensory (“bottom-up”) and cognitive (“top-down”) processes in literacy, the extent to which auditory or cognitive (memory or attention) learning transfers to phonological and reading skills remains unclear. Most research has demonstrated learning of the trained task or even learning transfer to a closely related task. However, few studies have reported “far-transfer” to a different domain, such as the improvement of phonological and reading skills following auditory or cognitive training. This study assessed the effectiveness of auditory, memory or attention training on far-transfer measures involving phonological and reading skills in typically developing children. Mid-transfer was also assessed through untrained auditory, attention and memory tasks. Sixty 5- to 8-year-old children with normal hearing were quasi-randomly assigned to one of five training groups: attention group (AG), memory group (MG), auditory sensory group (SG), placebo group (PG; drawing, painting), and a control, untrained group (CG). Compliance, mid-transfer and far-transfer measures were evaluated before and after training. All trained groups received 12 x 45-min training sessions over 12 weeks. The CG did not receive any intervention. All trained groups, especially older children, exhibited significant learning of the trained task. On pre- to post-training measures (test-retest), most groups exhibited improvements on most tasks. There was significant mid-transfer for a visual digit span task, with highest span in the MG, relative to other groups. These results show that both sensory and cognitive (memory or attention) training can lead to learning in the trained task and to mid-transfer learning on a task (visual digit span) within the same domain as the trained tasks. However, learning did not transfer to measures of language (reading and phonological awareness), as the PG and CG improved as much as the other trained groups. Further research is required to investigate the effects of various stimuli and lengths of training on the generalization of sensory and cognitive learning to literacy skills

Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia

Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading.Ellison Medical FoundationMartin Richmond Memorial FundNational Institutes of Health (U.S.). (Grant UL1RR025758)National Institutes of Health (U.S.). (Grant F32EY014750-01)MIT Class of 1976 (Funds for Dyslexia Research

Developmental delay and connective tissue disorder in four patients sharing a common microdeletion at 6q13-14

Interstitial deletions of the long arm of chromosome 6 are rare, and most reported cases represent large, cytogenetically detectable deletions. The implementation of array comparative genome hybridisation in the diagnostic work-up of patients presenting with congenital disorders, including developmental delay, has enabled identification of many patients with smaller chromosomal imbalances. In this report, the cases are presented of four patients with a de novo interstitial deletion of chromosome 6q13-14, resulting in a common microdeletion of 3.7 Mb. All presented with developmental delay, mild dysmorphism and signs of lax connective tissue. Interestingly, the common deleted region harbours 16 genes, of which COL12A1 is a good candidate for the connective tissue pathology

Psychophysical evidence for a general temporal processing deficit in children with dyslexia

The hypothesis of a general (i.e. cross-modal) temporal processing deficit in dyslexia was tested by examining rapid processing in both the auditory and the visual system in the same children with dyslexia. Participants were 10- to 12-year-old dyslexic readers and age-matched normal reading controls. Psychophysical thresholds were estimated for auditory gap and visual double flash detection, using a two-interval, two-alternative forced-choice paradigm. Significant group differences were found for the auditory and the visual test. Furthermore, temporal processing measures were significantly related to word and pseudo-word reading skills. As 70% of the dyslexic readers had significantly higher thresholds than controls for both auditory and visual temporal processing, the evidence tends to support the hypothesis of a general temporal processing deficit in children with dyslexia.status: publishe