Auditory event-related potentials measured in kindergarten predict later reading problems at school age.

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].

Newborn brain event-related potentials revealing atypical processing of sound frequency and the subsequent association with later literacy skills in children with familial dyslexia.

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.

Brain sensitivity to print emerges when children learn letter-speech sound correspondences.

The acquisition of reading skills is a major landmark process in a human's cognitive development. On the neural level, a new functional network develops during this time, as children typically learn to associate the well-known sounds of their spoken language with unfamiliar characters in alphabetic languages and finally access the meaning of written words, allowing for later reading. A critical component of the mature reading network located in the left occipito-temporal cortex, termed the "visual word-form system" (VWFS), exhibits print-sensitive activation in readers. When and how the sensitivity of the VWFS to print comes about remains an open question. In this study, we demonstrate the initiation of occipito-temporal cortex sensitivity to print using functional MRI (fMRI) (n = 16) and event-related potentials (ERP) (n = 32) in a controlled, longitudinal training study. Print sensitivity of fast (<250 ms) processes in posterior occipito-temporal brain regions accompanied basic associative learning of letter-speech sound correspondences in young (mean age 6.4 +/- 0.08 y) nonreading kindergarten children, as shown by concordant ERP and fMRI results. The occipito-temporal print sensitivity thus is established during the earliest phase of reading acquisition in childhood, suggesting that a crucial part of the later reading network first adopts a role in mapping print and sound.

Newborn event-related potentials predict poorer pre-reading skills in children at risk for dyslexia.

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.

Brain event-related potentials (ERPs) measured at birth predict later language development in children with and without familial risk for dyslexia.

We report associations between brain event-related potentials (ERPs) measured from newborns with and without familial risk for dyslexia and these same children's later language and verbal memory skills at 2.5, 3.5, and 5 years of age. ERPs to synthetic consonant-vowel syllables (/ba/, /da/, /ga/; presented equiprobably with 3,910-7,285 msec interstimulus intervals) were recorded from 26 newborns at risk for familial dyslexia and 23 control infants participating in the Jyväskylä Longitudinal Study of Dyslexia. The correlation and regression analyses showed that the at-risk type of response pattern at birth (a slower shift in polarity from positivity to negativity in responses to /ga/ at 540-630 msec) in the right hemisphere was related to significantly poorer receptive language skills across both groups at the age of 2.5 years. The similar ERP pattern in the left hemisphere was associated with poorer verbal memory skills at the age of 5 years. These results demonstrate that ERPs of newborns may be valid predictors of later language and neurocognitive outcomes.

Maturational effects on newborn ERPs measured in the mismatch negativity paradigm.

The mismatch negativity (MMN) component of event-related potentials (ERPs), a measure of passive change detection, is suggested to develop early in comparison to other ERP components, and an MMN-like response has been measured even from preterm infants. The MMN response in adults is negative in polarity at about 150-200 ms. However, the response measured in a typical MMN paradigm can also be markedly different in newborns, even opposite in polarity. This has been suggested to be related to maturational factors. To verify that suggestion, we measured ERPs of 21 newborns during quiet sleep to rarely occurring deviant tones of 1100 Hz (probability 12%) embedded among repeated standard tones of 1000 Hz in an oddball sequence. Gestational age (GA) and two cardiac measures, vagal tone (V) and heart period (HP), were used as measures of maturation. GA and HP explained between 36% and 42% of the total variance of the individual ERP peak amplitude (the largest deflection of the difference wave at a time window of 150-375 ms) at different scalp locations. In the discriminant function analyses, GA and HP as classifying variables differentiated infants in whom the peak of the difference wave had positive polarity from those with a negative polarity at an accuracy level ranging from 72% to 91%. These results demonstrate that during quiet sleep, maturational factors explain a significant portion of the ERP difference wave amplitude in terms of its polarity, indicating that the more mature the ERPs are, the more positive the amplitude. The present study suggests that maturational effects should be taken into account in ERP measurements using MMN paradigms with young infants.

The development of children at familial risk for dyslexia: birth to early school age.

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.

Brain responses to changes in speech sound durations differ between infants with and without familial risk for dyslexia.

A specific learning disability, developmental dyslexia, is a language-based disorder that is shown to be strongly familial. Therefore, infants born to families with a history of the disorder are at an elevated risk for the disorder. However, little is known of the potential early markers of dyslexia. Here we report differences between 6-month-old infants with and without high risk of familial dyslexia in brain electrical activation generated by changes in the temporal structure of speech sounds, a critical cueing feature in speech. We measured event-related brain responses to consonant duration changes embedded in ata pseudowords applying an oddball paradigm, in which pseudoword tokens with varying /t/ duration were presented as frequent standard (80%) or as rare deviant stimuli (each 10%) with an interval of 610 msec between the stimuli. The infants at risk differ from control infants in both their initial responsiveness to sounds per se and in their change-detection responses dependent on the stimulus context. These results show that infants at risk due to a familial background of reading problems process auditory temporal cues of speech sounds differently from infants without such a risk even before they learn to speak.