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Dyslexia is a neurobiological disorder impairing learning to read. Brain responses of infants at genetic risk for dyslexia are abnormal already at birth, and associations from infant speech perception to preschool cognitive skills and reading in early school years have been documented, but there are no studies showing predicting power until adolescence. Here we show that in at-risk infants, brain activation to pseudowords at left hemisphere predicts 44% of reading speed at 14 years, and even improves the prediction after taking into account neurocognitive preschool measures of letter naming, phonology, and verbal short-term memory. The association between infant brain responses and reading speed is mediated by preschool rapid automatized naming ability. Therefore, we suggest that rapid naming and reading speed could share a similar cognitive process of automatized access to lexicon via phonological representations, and brain activation to speech sounds in infancy probably acts as an index of deficient development of the same process., (Copyright © 2017. Published by Elsevier Ltd.)

Multiple risk factors can affect the development of specific reading problems or dyslexia. In addition to the most prevalent and studied risk factor, phonological processing, auditory discrimination problems have also been found in children and adults with reading difficulties. The present study examined 37 children between the ages of 5 and 6, 11 of which had multiple risk factors for developing reading problems. The children participated in a passive oddball EEG experiment with sinusoidal sounds with changes in sound frequency, duration, or intensity. The responses to the standard stimuli showed a negative voltage shift in children at risk for reading problems compared to control children at 107-215 ms in frontocentral areas corresponding to P1 offset and N250 onset. Source analyses showed that the difference originated from the left and right auditory cortices. Additionally, the children at risk for reading problems had a larger late discriminative negativity (LDN) response in amplitude for sound frequency change than the control children. The amplitudes at the P1-N250 time window showed correlations to letter knowledge and phonological identification whereas the amplitudes at the LDN time window correlated with verbal short-term memory and rapid naming. These results support the view that problems in basic auditory processing abilities precede the onset of reading instruction and can act as one of the risk factors for dyslexia., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Specific reading disability, dyslexia, is a prevalent and heritable disorder impairing reading acquisition characterized by a phonological deficit. However, the underlying mechanism of how the impaired phonological processing mediates resulting dyslexia or reading disabilities remains still unclear. Using ERPs we studied speech sound processing of 30 dyslexic children with familial risk for dyslexia, 51 typically reading children with familial risk for dyslexia, and 58 typically reading control children. We found enhanced brain responses to shortening of a phonemic length in pseudo-words (/at:a/ vs. /ata/) in dyslexic children with familial risk as compared to other groups. The enhanced brain responses were associated with better performance in behavioral phonemic length discrimination task, as well as with better reading and writing accuracy. Source analyses revealed that the brain responses of sub-group of dyslexic children with largest responses originated from a more posterior area of the right temporal cortex as compared to the responses of the other participants. This is the first electrophysiological evidence for a possible compensatory speech perception mechanism in dyslexia. The best readers within the dyslexic group have probably developed alternative strategies which employ compensatory mechanisms substituting their possible earlier deficit in phonological processing and might therefore be able to perform better in phonemic length discrimination and reading and writing accuracy tasks. However, we speculate that for reading fluency compensatory mechanisms are not that easily built and dyslexic children remain slow readers during their adult life., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A review of research that uses behavioral, electroencephalographic, and/or magnetoencephalographic methods to investigate auditory processing deficits in individuals with dyslexia is presented. Findings show that measures of frequency, rise time, and duration discrimination as well as amplitude modulation and frequency modulation detection were most often impaired in individuals with dyslexia. Less consistent findings were found for intensity and gap perception. Additional factors that mediate auditory processing deficits in individuals with dyslexia and their implications are discussed.

Identifying children at risk for reading problems or dyslexia at kindergarten age could improve support for beginning readers. Brain event-related potentials (ERPs) were measured for temporally complex pseudowords and corresponding non-speech stimuli from 6.5-year-old children who participated in behavioral literacy tests again at 9 years in the second grade. Children who had reading problems at school age had larger N250 responses to speech and non-speech stimuli particularly at the left hemisphere. The brain responses also correlated with reading skills. The results suggest that atypical auditory and speech processing are a neural-level risk factor for future reading problems. [Supplementary material is available for this article. Go to the publisher's online edition of Developmental Neuropsychology for the following free supplemental resources: Sound files used in the experiments. Three speech sounds and corresponding non-speech sounds with short, intermediate, and long gaps].

Perception of speech at multiple temporal scales is important for the efficient extraction of meaningful phonological elements. Individuals with developmental dyslexia have difficulty in the accurate neural representation of phonological aspects of speech, across languages. Recently, it was proposed that these difficulties might arise in part because of impaired phase locking to the slower modulations in the speech signal (<10 Hz), which would affect syllabic parsing and segmentation of the speech stream (the "temporal sampling" hypothesis, Goswami, 2011). Here we measured MEG responses to different rates of amplitude modulated white noise in adults with and without dyslexia. In line with the temporal sampling hypothesis, different patterns of phase locking to amplitude modulation at the delta rate of 2 Hz were found when comparing participants with dyslexia to typically-reading participants. Typical readers exhibited better phase locking to slow modulations in right auditory cortex, whereas adults with dyslexia showed more bilateral phase locking. The results suggest that oscillatory phase locking mechanisms for slower temporal modulations are atypical in developmental dyslexia., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Dyslexia is characterized by deficits in phonological processing abilities. However, it is unclear what the underlying factors for poor phonological abilities or speech sound representations are. One hypothesis suggests that individuals with dyslexia have problems in basic acoustic perception which in turn can also cause problems in speech perception. Here basic auditory processing was assessed by auditory event-related potentials recorded for paired tones presented in an oddball paradigm in 9-year-old children with dyslexia and a familial background of dyslexia, typically reading children at familial risk for dyslexia and control children without risk for dyslexia. The tone pairs elicited a P1-N250 complex with emerging N1-P2 complex. Control children showed larger responses over the left-than-right hemisphere at the P1 and P2 time windows for both short and long within-pair intervals (WPI; 10 and 255ms) whereas children with dyslexia showed this pattern only for the tone pairs with the long WPI. The response for the pairs with the short WPI showed equal amplitudes over both hemispheres in children with dyslexia. The findings indicate that individuals with dyslexia process basic auditory information differently when the tones are within the temporal window of integration., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Dyslexia is a learning difficulty affecting the acquisition of fluent reading and spelling skills due to poor phonological processing. Underlying deficits in processing sound rise time have also been found in children and adults with dyslexia. However, the neural basis for these deficits is unknown. In the present study event-related potentials were used to index neural processing and examine the effect of rise time manipulation on the obligatory N1, T-complex and P2 responses in English speaking adults with and without dyslexia. The Tb wave of the T-complex showed differences between groups, with the amplitudes for Tb becoming less negative with increased rise time for the participants with dyslexia only. Frontocentral N1 and P2 did not show group effects. Enhanced Tb amplitude that is modulated by rise time could indicate altered neural networks at the lateral surface of the superior temporal gyrus in adults with dyslexia., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The role played by an auditory-processing deficit in dyslexia has been debated for several decades. In a longitudinal study using brain event-related potentials (ERPs) we investigated 1) whether dyslexic children with familial risk background would show atypical pitch processing from birth and 2) how these newborn ERPs later relate to these same children's pre-reading cognitive skills and literacy outcomes. Auditory ERPs were measured at birth for tones varying in pitch and presented in an oddball paradigm (1100 Hz, 12%, and 1000 Hz, 88%). The brain responses of the typically reading control group children (TRC group, N=25) showed clear differentiation between the frequencies, while those of the group of reading disability with familial risk (RDFR, 8 children) and the group of typical readers with familial risk (TRFR, 14 children) did not differentiate between the tones. The ERPs of the latter two groups differed from those of the TRC group. However, the two risk groups also showed a differential hemispheric ERP pattern. Furthermore, newborn ERPs reflecting passive change detection were associated with phonological skills and letter knowledge prior to school age and with phoneme duration perception, reading speed (RS) and spelling accuracy in the 2nd grade of school. The early obligatory response was associated with more general pre-school language skills, as well as with RS and reading accuracy (RA). Results suggest that a proportion of dyslexic readers with familial risk background are affected by atypical auditory processing. This is already present at birth and also relates to pre-reading phonological processing and speech perception. These early differences in auditory processing could later affect phonological representations and reading development. However, atypical auditory processing is unlikely to suffice as a sole explanation for dyslexia but rather as one risk factor, dependent on the genetic profile of the child., (Copyright © 2010 Elsevier Srl. All rights reserved.)

Earlier results from the Jyväskylä Longitudinal Study of Dyslexia showed that newborn event-related potentials (ERPs) of children with and without familial risk for dyslexia were associated with receptive language and verbal memory skills between 2.5 and 5 years of age. We further examined whether these ERPs (responses to synthetic consonant-vowel syllables /ba/, /da/, /ga/; presented equiprobably with 3,910-7,285 ms interstimulus intervals) predict later pre-reading skills measured before the onset of school (6.5 years of age). In line with our earlier results, the at-risk children (N = 11) with atypical speech processing in the right hemisphere (a slower shift in polarity from positivity to negativity in responses to /ga/ at 540-630 ms) scored significantly lower in phonological skills, rapid naming, and letter knowledge than the control children (N = 10) without enhanced right hemispheric speech processing. These results further extend our earlier findings of newborn ERPs in predicting poorer language skills. These consistent differences in ERPs to speech sounds may have applications in the future for the early identification of children at risk for developmental language problems. This would facilitate well-directed intervention even before reading problems are typically diagnosed.

Development of reading skills has been shown to be tightly linked to phonological processing skills and to some extent to speech perception abilities. Although speech perception is also known to play a role in reading development, it is not clear which processes underlie this connection. Using event-related potentials (ERPs) we investigated the speech processing mechanisms for common and uncommon sound contrasts (/ba/-/da/-/ga/ and /ata/-/at: a/) with respect to the native language of school-age children in Finland and the US. In addition, a comprehensive behavioral test battery of reading and phonological processing was administered. ERPs revealed that the children could discriminate between the speech sound contrasts (place of articulation and phoneme length) regardless of their native language. No differences emerged between the Finnish and US children in their change detection responses. The brain responses to the phoneme length contrast, however, correlated robustly with reading scores in the US children, with larger responses being linked to poorer reading skills. Finnish children also showed correlations between the reading and phonological measures and ERP responses, but the pattern of results was not as clear as for the US children. The results indicate that speech perception is linked to reading skills and this link is more robust for uncommon speech sound contrasts.

A review of research that uses behavioral, electroencephalographic, and/or magnetoencephalographic methods to investigate auditory processing deficits in individuals with dyslexia is presented. Findings show that measures of frequency, rise time, and duration discrimination as well as amplitude modulation and frequency modulation detection were most often impaired in individuals with dyslexia. Less consistent findings were found for intensity and gap perception. Additional factors that mediate auditory processing deficits in individuals with dyslexia and their implications are discussed.

Development of reading skills has been shown to be tightly linked to phonological processing skills and to some extent to speech perception abilities. Although speech perception is also known to play a role in reading development, it is not clear which processes underlie this connection. Using event-related potentials (ERPs) we investigated the speech processing mechanisms for common and uncommon sound contrasts (/ba/-/da/-/ga/ and /ata/-/at: a/) with respect to the native language of school-age children in Finland and the US. In addition, a comprehensive behavioral test battery of reading and phonological processing was administered. ERPs revealed that the children could discriminate between the speech sound contrasts (place of articulation and phoneme length) regardless of their native language. No differences emerged between the Finnish and US children in their change detection responses. The brain responses to the phoneme length contrast, however, correlated robustly with reading scores in the US children, with larger responses being linked to poorer reading skills. Finnish children also showed correlations between the reading and phonological measures and ERP responses, but the pattern of results was not as clear as for the US children. The results indicate that speech perception is linked to reading skills and this link is more robust for uncommon speech sound contrasts. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the development of morphological awareness and reading skills are interlinked. However, most have focused on phonological awareness as a risk factor for dyslexia, although there is considerable diversity in the underlying causes of this reading difficulty. Specifically, the relationship between phonology, derivational morphology, and dyslexia in the Finnish language remains unclear. In the present study, we used magnetoencephalography (MEG) to measure the brain responses to correctly and incorrectly derived Finnish nouns in 34 first grade Finnish children (21 typically developing and 13 with familial risk for dyslexia). In addition, we compared longitudinally the morphological information processing of 27 children (16 typically developing and 11 at-risk for dyslexia) first at pre-school age and then at first grade age. The task consisted of 108 pairs of sentences, including a verb and its root with the derivational suffix/-jA/. Correctly and incorrectly derived forms were presented both as real words and pseudowords. The incorrectly derived nouns contained a morpho-phonological violation in the last vowel of the noun before the derivational suffix. The brain activation of the typically developing children in response to morphological information processing showed sensitivity to the morphologically correct vs. incorrect contrast only in the cases of the real words. Children at-risk for dyslexia showed sensitivity to the morphological information processing both for real words and pseudowords. However, no significant differences between the groups emerged either for the correct vs. incorrect morphological contrast or for the correctly and incorrectly derived forms separately. Interestingly, in our previous study, cluster-based permutation tests showed significant developmental behavioral and brain differences between the children at pre-school age and at first-grade age in the morphological information processing of real words and pseudowords. Our results indicate the important role of derivational morphology in the early phases of learning to read. • We examined morphological information processing in first grade children with and without risk for dyslexia with MEG. • The brain activity of the children without risk showed sensitivity to morphological information only for real nouns. • The children at-risk showed similar activity with typically developing children for real derived nouns and pseudo nouns. • No between group differences were found for the processing of the correct vs. incorrect nouns and pseudo nouns. • Significant developmental differences were found between ages, but no differences were found between groups. [ABSTRACT FROM AUTHOR]

Purpose: The authors investigated the importance of phonemic length discrimination ability on reading and spelling skills among children with reading disabilities and familial risk for dyslexia and among children with typical reading skills, as well as the role of prereading skills in reading and spelling development in children with reading disabilities. Method: Finnish children with reading disabilities and discrimination problems (RDDP, n = 13), children with reading disabilities and typical discrimination abilities (RDTD, n = 27), and children with typical reading skills (TR, n = 140) were assessed between the ages of 1 and 6.5 years for language, phonological awareness, IQ, verbal memory, and rapid automatized naming. IQ, discrimination ability, and reading and spelling skills were assessed in the second grade. Statistical differences were examined at the group level. Results: The RDDP group was poorer in spelling accuracy compared with the other groups. The RDDP group's prereading skills were poorer than those of the RDTD group. In regression analyses, the RDDP group's poor spelling skills were partially explained by their discrimination ability. Conclusion: Prereading skills are connected to poor reading skills, but phonemic length discrimination ability plays a critical role in spelling accuracy problems among children with reading disabilities and with familial risk for dyslexia. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The perception of syllable stress has not been widely studied in developmental dyslexia, despite strong evidence for auditory rhythmic perceptual difficulties. Here we investigate the hypothesis that perception of sound rise time is related to the perception of syllable stress in adults with developmental dyslexia. Methods: A same-different stress perception task was devised and delivered to a sample of 40 adults in two formats, one using pairs of identical 4-syllable words and one using pairs of two different 4-syllable words. Auditory perception of rise time, frequency and intensity, and phonological awareness, phonological memory and reading were also measured. Results: We show that adults with dyslexia performed significantly more poorly in both versions of the stress perception task. Individual differences in the perception of rise time were linked to the accuracy of performance. Conclusions: To our knowledge this is the first direct demonstration of syllable stress perception deficits in dyslexia. The accurate perception of intonational patterning and rhythm may be critical for the development of the phonological lexicon and consequently for the development of literacy. Even high-functioning compensated adults with dyslexia show impairments in speech processing. [Copyright &y& Elsevier]

Purpose: To examine the ability to discriminate phonemic length and the association of this ability with reading accuracy, reading speed, and spelling accuracy in Finnish children throughout Grades 1-3. Method: Reading-disabled (RDFR, n = 35) and typically reading children (TRFR, n = 69) with family risk for dyslexia and typically reading control children (TRC, n = 80) were tested once in each grade of Grades 1-3 using a phonemic length discrimination task. Reading, spelling, IQ, verbal short-term memory, phonological memory, and naming speed were assessed. Results: The RDFR group made more errors in phonemic length discrimination than the TRC group in Grades 2 and 3. After taking into account variance in verbal short-term memory, phonological memory, and naming speed, discrimination ability explained unique variance of spelling accuracy in Grades 2 and 3 and reading accuracy in Grade 3 in the RDFR group. At the individual level, in Grade 2, 31.4% of the RDFR group and 14.7% of the TRFR group performed below -1.25 SDs in the phonemic length discrimination task. Conclusion: Problems in phonemic length discrimination could be one of the accumulating risk factors affecting development leading to dyslexia. [ABSTRACT FROM AUTHOR]

Difficulties in phonological processing and speech perception are associated with developmental dyslexia, but there is considerable diversity across people with developmental dyslexia (e.g., dyslexics with and without phonological difficulties). Phonological and morphological awareness are both known to play an important role in reading acquisition. Problems in morpho-phonological information processing could arguably be associated with developmental dyslexia, especially for Finnish, which is a rich morphologically language. We used MEG to study the connection between morpho-phonology in the Finnish language and familial risk for developmental dyslexia. We measured event-related fields (ERFs) of 22 pre-school children without risk and 18 children with familial risk for developmental dyslexia during a morphological task. Pairs of sentences consisting of a verb and its derived noun with the derivational suffix/–jA/and pairs of sentences consisting of a pseudo-verb and its pseudo-noun ending with the same suffix were presented to the participants. The derived nouns were also divided into correctly and incorrectly derived forms. Incorrectly derived forms contained an incorrect morpho-phonological change in the last vowel before the derivational suffix/-jA/. Both typically developing children and children at-risk for developmental dyslexia were sensitive to the morphological information, both in the case of real words and pseudowords, as shown by the sensor level analysis and cluster-based permutation tests for the responses to the morphologically correct vs. incorrect contrast. The groups showed somewhat different response patterns to this contrast. However, no significant differences were found in the between-group differences. No significant differences emerged between typically developing children and children at-risk for developmental dyslexia neither for real words nor for pseudowords. Overall, these findings suggest that pre-school children with and without risk for developmental dyslexia are already sensitive to the processing of morpho-phonological information before entering school. • We examined the neural correlates of morphological information processing in pre-school children with and without familial risk for developmental dyslexia using sentences with verbs and derived nouns and pseudo nouns during MEG recordings. • Brain activity of typically developing children showed sensitivity to the morphological information, both in the case of real words and pseudowords. • The brain responses to the morphological information processing of children with familial risk for developmental dyslexia showed comparable activity to those of the control children. • However, the brain data did not reveal any group differences for the processing of the correctly and incorrectly derived words and pseudowords. [ABSTRACT FROM AUTHOR]

Brain imaging results illustrative of the search for neuronal markers of dyslexia are reviewed. Event-related potentials (ERPs) are shown to be effective indices of auditory processes involved in speech perception and thus, apparently also helpful in uncovering the neuronal basis of language problems associated with difficulties in reading. Results from the authors' laboratory show that, even at a very early age, brain responses (ERPs) to speech sounds can differentiate children with and without risk for dyslexia and also show reliable predictive correlations to later language development and reading acquisition. The review also covers dyslexia research in which other brain imaging techniques have been applied. The most recent imaging studies have opened interesting views to functional changes associated the remediation of reading problems. [ABSTRACT FROM AUTHOR]