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This study combines wavelet decomposition and independent component analysis (ICA) to extract mismatch negativity (MMN) from electroencephalography (EEG) recordings. As MMN is a small event-related potential (ERP), a systematic ICA based approach is designed, exploiting MMN's temporal, frequency and spatial information. Moreover, this study answers which type of EEG recordings is more appropriate for ICA to extract MMN, what kind of the preprocessing is beneficial for ICA decomposition, which algorithm of ICA can be chosen to decompose EEG recordings under the selected type, how to determine the desired independent component extracted by ICA, how to improve the accuracy of the back projection of the selected independent component in the electrode field, and what can be finally obtained with the application of ICA. Results showed that the proposed method extracted MMN with better properties than those estimated by difference wave only using temporal information or ICA only using spatial information. The better properties mean that the deviant with larger magnitude of deviance to repeated stimuli in the oddball paradigm can elicit MMN with larger peak amplitude and shorter latency. As other ERPs also have the similar information exploited here, the proposed method can be used to study other ERPs. [ABSTRACT FROM AUTHOR]

Four genes, DYX1C1, ROBO1, DCDC2 and KIAA0319 have been studied both genetically and functionally as candidate genes for developmental dyslexia, a common learning disability in children. The identification of novel genes is crucial to better understand the molecular pathways affected in dyslectic individuals. Here, we report results from a fine-mapping approach involving linkage and association analysis in Finnish and German dyslexic cohorts. We restrict a candidate region to 0.3 Mb on chromosome 7q33. This region harbours the gene diacylglycerol kinase, iota ( DGKI) which contains overlapping haplotypes associated with dyslexia in both Finnish and German sample sets. [ABSTRACT FROM AUTHOR]

Outcomes of two training programs aimed at improving reading speed for 39 German-speaking poor readers in grades 2 and 4 were evaluated. During a 6-week training period, a specific target for children in a computer group was to improve reading of word-initial consonant clusters by practice in associating an orthographic unit with a corresponding phonological unit. Children in a paired reading group read books with an adult tutor. The results showed that, in reading words in which the computer-trained sublexical items were included, both groups exhibited similar improvement. A post hoc analysis suggested that computer training was associated with better reading skills with respect to the trained sublexical items; however, this improvement did not show large generalization effects to the words with the sublexical items. The paired reading group showed a more rapid gain in global word reading fluency than the computer group. Neither of the groups improved their pseudoword reading. [ABSTRACT FROM AUTHOR]

Outcomes of three different types of computerized training in sub-lexical items (word-initial consonant clusters) on reading speed for 39 German-speaking poor readers in Grades 2 and 3 were evaluated. A phonological–orthographic association group, a reading aloud group, and a combined group were compared in performance with an untrained control group. During short-term training, the intervention groups showed higher gains than the control group in reading speed of the trained sub-lexical items and of the words containing the trained segments. No differences were found between the intervention groups. In the development of pseudoword reading, the groups did not show differential improvements. The generalization effect to pseudoword reading was similar, whether the pseudowords contained the trained segment as a syllable or as a non-syllabic letter string. The gains induced by training were specific to the materials used in training and did not induce gains in general reading speed. [ABSTRACT FROM AUTHOR]

The present findings are drawn from the Jyväiskyläi Longitudinal Study of Dyslexia (JLD), in which approximately 100 children with familial risk of dyslexia and 100 control children have been followed from birth. In this paper we report data on the reading development of the JLD children and their classmates, a total of 1,750 children from four measurement points during the first two school years. In the total sample, we examined whether heterogeneous developmental paths can be identified based on profiles of word recognition and reading comprehension. Secondly, we studied what kind of early language and literacy skill profiles and reading experiences characterize the children with differing reading development in the follow-up sample. The mixture modeling procedure resulted in five subtypes: (1) poor readers, (2) slow decoders, (3) poor comprehenders, (4) average readers, and (5) good readers. The children with familial risk for dyslexia performed on average at a lower level in all reading tasks than both their classmates and the controls, and they were overrepresented in slow decoders subtype. Differences between the subtypes were found in the early language and literacy skill development, as well as in the reading experiences of the reading subtypes. [ABSTRACT FROM AUTHOR]

The relationship between late-talkers' language development and reading and spelling outcomes was examined in children with and without familial risk for dyslexia. The late-talking subgroups were defined using parent- and test-based assessments of receptive and expressive vocabulary and grammar at 2 and 2.5 years as intake criteria. The language skills of late talkers and the remainders of these two groups were assessed at 3.5, 5, and 5.5 years. Reading/spelling outcomes were compared at the end of the second grade. Late-talking toddlers of the at-risk group who had both poor receptive and expressive skills performed less well than all other groups on language measurements at 5.5 years. In contrast, the control group's late talkers with an expressive delay reached the language level of their age-mates already by 3.5 years, and maintained their age-appropriate position two years later. The most significant differences in the reading skills were found between the at-risk children with receptive and expressive delay and the remainder of the controls. Age-appropriate early language skills did not, however, ensure norm-level fluent reading in the at-risk group. The remainder of the at-risk group performed at a significantly lower level than did the remainder of the controls, both on the oral reading and spelling tasks. [ABSTRACT FROM AUTHOR]

Children at risk for familial dyslexia (n = 107) and their controls (n = 93) have been followed from birth to school entry in the Jyvaskyla Longitudinal study of Dyslexia (JLD) on developmental factors linked to reading and dyslexia. At the point of school entry, the majority of the at-risk children displayed decoding ability that fell at least 1 SD below the mean of the control group. Measures of speech processing were the earliest indices to show both group differences in infancy and also significant predictive associations with reading acquisition. A number of measures of language, including phonological and morphological skill collected repeatedly from age three, revealed group differences and predictive correlations. Both the group differences and the predictive associations to later language and reading ability strengthened as a function of increasing age. The predictions, however, tend to be stronger and the spectrum of significant correlations wider in the at-risk group. These results are crucial to early identification and intervention of dyslexia in at-risk children. [ABSTRACT FROM AUTHOR]

Emerging phonological awareness was compared in two groups of 3.5-year-old children belonging to the Jyväskylä Longitudinal Study of Dyslexia (JLD): children with familial risk of dyslexia (at-risk group n = 98) and children without such risk (control group n = 91). Four computer animated tasks were used: Word-level and Syllable-level Segment Identification, Synthesis, and Continuation of Phonological Units. The control group children manifested higher mastery than children in the at-risk group in phonological awareness, and the proportion of children with a low phonological awareness mean score was 2.5 times higher in the at-risk group than in the control group. In both groups, phonological awareness at 3.5 years was predicted by early language skills assessed between 14 and 26 months of age, and it was also associated with concurrent language. The difference between the at-risk and control group at 3.5-year in phonological awareness remained significant, even when the effect of other language skills such as productive and receptive vocabulary, and mastery of inflections, measured both at earlier ages and concurrently were controlled for. Our findings indicate that familial risk for dyslexia is reliably reflected in emerging phonological awareness already at this early age and it can be assessed independently of other language skills. [ABSTRACT FROM AUTHOR]

Developmental dyslexia, or reading disability, is a multigenic complex disease for which at least five loci, i.e. DYX1–3 and DYX5–6, have been clearly identified from the human genome. To date, DYX1C1 is the only dyslexia candidate gene cloned. We have previously reported linkage to 2p11 and 7q32 in 11 Finnish pedigrees. Here, we report the fine mapping of the approximately 40-cM linked region from chromosome 2 as we increased marker density to one per 1.8 cM. Linkage was supported with the highest NPL score of 3.0 (P=0.001) for marker D2S2216. Association analysis using the six pedigrees showing linkage pointed to marker D2S286/rs3220265 (P value <0.001) in the near vicinity of D2S2216. We went on to further characterise this ~15-cM candidate region (D2S2110-D2S2181) by adding six SNPs covering ~670 kb centred at D2S286/rs3220265. A haplotype pattern could no longer be observed in this region, which was therefore excluded from the candidate area. This also excluded the TACR1 (tachykinin receptor 1) gene, located at marker D2S286. The dyslexia candidate region on 2p11 is, therefore, now limited to the chromosomal area D2S2116-D2S2181, which is ~12 Mbp of human sequence and is at a distinct location from the previously reported DYX3 locus, raising the possibility of two distinct loci on chromosome 2p. [ABSTRACT FROM AUTHOR]

Genetic studies of complex traits have become increasingly successful as progress is made in next-generation sequencing. We aimed at discovering single nucleotide variation present in known and new candidate genes for developmental dyslexia: CYP19A1, DCDC2, DIP2A, DYX1C1, GCFC2 (also known as C2orf3), KIAA0319, MRPL19, PCNT, PRMT2, ROBO1 and S100B. We used next-generation sequencing to identify single-nucleotide polymorphisms in the exons of these 11 genes in pools of 100 DNA samples of Finnish individuals with developmental dyslexia. Subsequent individual genotyping of those 100 individuals, and additional cases and controls from the Finnish and German populations, validated 92 out of 111 different single-nucleotide variants. A nonsynonymous polymorphism in DCDC2 (corrected P=0.002) and a noncoding variant in S100B (corrected P=0.016) showed a significant association with spelling performance in families of German origin. No significant association was found for the variants neither in the Finnish case-control sample set nor in the Finnish family sample set. Our findings further strengthen the role of DCDC2 and implicate S100B, in the biology of reading and spelling. [ABSTRACT FROM AUTHOR]

We investigated the relationship between apolipoprotein E (apoE) polymorphism and cardiovascular responses to experimentally induced mental stress. Mental stress was induced in 28 healthy 16-year-old boys with a series of stressors (e.g., mental arithmetic, Stroop Color-Word Interference Test). Heart rate (HR), finger blood volume, and skin conductance level were recorded continuously during the task performance. We found that boys with apoE3/2 or apoE3/3 showed marginally significantly greater HR reactivity and significantly greater task levels of HR and HR variability (HRV) during the mental stress than subjects with apoE4/2, apoE4/3, or apoE4/4. In addition, E4/2, E4/3, and E4/4 subjects manifested a distinct stress-related decrease in HRV relative to baseline values while E3/2 and E3/3 subjects showed a slight increase. The results suggests that apoE polymorphism is associated with cardiovascular responsivity to mental stress in adolescent boys. [ABSTRACT FROM AUTHOR]