Neurocognitive Development and Predictors of L1 and L2 Literacy Skills in Dyslexia: A Longitudinal Study of Children 5-11 Years Old

Brain Laterality in Dyslexia Seen during Literacy Development and Early Training

During the period in which children learn to read and write, a gradual shift from right to left hemisphere dominance for language is typically seen. However, in children with dyslexia, a deviant pattern is described in the literature. As part of a larger longitudinal study (The Bergen Longitudinal Dyslexia Study), the present study aimed to assess this development from an early age before children learn to read and write. Dichotic listening (DL), which is a non-invasive test, was used to assess the development of brain laterality in a Typical group and a Dyslexia group. The participants received yearly sessions of evidence-based literacy training at ages 5 to 7. The Typical group showed increasing ear scores and a shift from no ear advantage in the Pre-literacy stage (age 6), indicative of no hemisphere dominance, to a right ear advantage, indicative of a left hemisphere dominance, in the Emergent literacy stage (age 8) and the Literacy stage (age 11). The Dyslexia group showed a different pattern, with a significant right ear advantage at age 6, indicative of a right hemisphere dominance, and increasing ear scores at ages 8 and 11; however, no ear dominance was observed in the Literacy stage. The results point to an effect of relevant, evidence-based training affecting both right and left hemispheres in dyslexia, which should form a basis for further research.

Infant neural speech encoding is associated with pre-reading skill development

OBJECTIVE

We longitudinally investigated whether infant P1 and N2 ERPs recorded in newborns and at 28 months could predict pre-reading skills at 28 months and 4-5 years.

METHODS

We recorded ERPs to a pseudoword in newborns and at 28 months in a sample over-represented by infants with familial dyslexia risk. Using multiple linear regression models, we examined P1 and N2 associations with pre-reading skills at 28 months and 4-5 years.

RESULTS

Shorter latencies of the newborn P1 predicted faster serial naming at 28 months. Larger amplitudes and shorter latencies of P1 at 28 months predicted better serial naming abilities and auditory working memory across the pre-reading stage. Right-lateralized P1 and N2 were related to poorer pre-reading skills.

CONCLUSIONS

Infant ERPs, particularly P1, providing information about neural speech encoding abilities, are associated with pre-reading skill development.

SIGNIFICANCE

Infant and early childhood neural speech encoding abilities may work as early predictive markers of reading development and impairment. This study may help to plan early interventions targeting phonological processing to prevent or ameliorate learning deficits.

Infant mismatch responses to speech-sound changes predict language development in preschoolers at risk for dyslexia

OBJECTIVE

We investigated how infant mismatch responses (MMRs), which have the potential for providing information on auditory discrimination abilities, could predict subsequent development of pre-reading skills and the risk for familial dyslexia.

METHODS

We recorded MMRs to vowel, duration, and frequency deviants in pseudo-words at birth and 28 months in a sample over-represented by infants with dyslexia risk. We examined MMRs' associations with pre-reading skills at 28 months and 4-5 years and compared the results in subgroups with vs. without dyslexia risk.

RESULTS

Larger positive MMR (P-MMR) at birth was found to be associated with better serial naming. In addition, increased mismatch negativity (MMN) and late discriminative negativity (LDN), and decreased P-MMR at 28 months overall, were shown to be related to better pre-reading skills. The associations were influenced by dyslexia risk, which was also linked to poor pre-reading skills.

CONCLUSIONS

Infant MMRs, providing information about the maturity of the auditory system, are associated with the development of pre-reading skills. Speech-processing deficits may contribute to deficits in language acquisition observed in dyslexia.

SIGNIFICANCE

Infant MMRs could work as predictive markers of atypical linguistic development during early childhood. Results may help in planning preventive and rehabilitation interventions in children at risk of learning impairments.

Disentangling dyslexia from typical L2-learning in emergent literacy

The present paper assessed how dyslexia can be identified in school children with another language than their first language. Participants were school children with Norwegian as their second language (L2), and two groups of children with Norwegian as their first language (L1): a control group (L1-Con), and a dyslexia group (L1-Dys). All were 2nd and 3rd graders who had attended Norwegian schools from 1st grade on. None of the individuals in L1-Con or the L2 group were identified with any learning disability. However, slow literacy progress was seen in some L2-children. The children were tested individually within the symptomatic and cognitive levels. Results were analysed in two steps: (1) group comparisons; (2) L2 individual profiles and tentative L2 subgrouping. An unexpected L2 profile showed language scores below norm, coupled with some scores within and some scores above norm within the cognitive domain. Case assessment of the L2 group resulted in three subgroups: one comparable to L1-Con, one comparable to L1-Dys, and one with a result in between these two groups. Low linguistic scores cannot be considered valid markers of dyslexia in L2. Within the cognitive domain, a variety of low scores can indicate dyslexia, while high scores can be compensatory.

Writing proficiency in English as L2 in Spanish children with dyslexia

Different studies have demonstrated that people with dyslexia have difficulties in acquiring fluent reading and writing. These problems are also evident when they learn a second language. The aim of our study was to investigate if there is a linguistic transfer effect for writing in children with dyslexia when they face tasks in English (L2), as well as the possible influence of other linguistic skills (spelling, vocabulary and reading) in English (L2) and in Spanish (L1). Participants completed a series of tasks both in Spanish and English: a picture naming task, a word reading task, a word spelling task, and a written composition of which we analysed its quality through different variables provided by the Coh-metrix software. Our results revealed that children with dyslexia show similar or parallel performance in written composition in both languages, which could imply a language transfer effect from L1 and L2. Besides, basic language skills are related to the characteristics of written composition to a greater extent in English than in Spanish, suggesting the impact of these on the quality of written composition.

Shallow or deep? The impact of orthographic depth on visual processing impairments in developmental dyslexia

The extent to which impaired visual and phonological mechanisms may contribute to the manifestation of developmental dyslexia across orthographies of varying depth has yet to be fully established. By adopting a cross-linguistic approach, the current study aimed to explore the nature of visual and phonological processing in developmental dyslexic readers of shallow (Italian) and deep (English) orthographies, and specifically the characterisation of visual processing deficits in relation to orthographic depth. To achieve this aim, we administered a battery of non-reading visual and phonological tasks. Developmental dyslexics performed worse than typically developing readers on all visual and phonological tasks. Critically, readers of the shallow orthography were disproportionately impaired on visual processing tasks. Our results suggest that the impaired reading and associated deficits observed in developmental dyslexia are anchored by dual impairments to visual and phonological mechanisms that underpin reading, with the magnitude of the visual deficit varying according to orthographic depth.

Kindergarten screening tools filled out by parents and teachers targeting dyslexia. Predictions and developmental trajectories from age 5 to age 15 years

The concept of early 'efforts' has led to discussions for and against introducing language assessment for all kindergarten children. Evidence-based kindergarten screening tools completed by close caregivers could solve this controversy as the children themselves would only be indirectly involved. The aim of this study was to see whether the scores of such early screening tools aiming at developmental dyslexia could predict school marks of literacy competence 10 years later, and to see whether these screening tools would reveal different dyslexia trajectories. The study is part of the Bergen Longitudinal Dyslexia Study, and the results from individual testing are reported elsewhere. Here, the caregivers' views isolated from the rest of the study are focused. Three tools were used: the RI-5, a questionnaire assessing the risk of dyslexia; the TRAS, a non-standardized observation tool of children's communication skills; and the CCC-2, a questionnaire assessing Developmental Language Disorders. Screening was performed at age 5 (TP1), age 11, (TP2) and age 15 (TP3). At TP2, when dyslexia was identified, 13 children formed the dyslexia group, and the rest formed the control group. At TP3, the RI-5 and CCC-2 turned out to be predictive of literacy competence as measured by school marks. Developmental trajectories were seen through the regroupings and scorings into a persistent group, a late onset group and a resolving group. Evidence-based preschool screening tools filled out by close caregivers offer valid information on later literacy developmental trajectories.

Foreign Language Attainment of Children/Adolescents with Poor Literacy Skills: a Systematic Review and Meta-analysis

This systematic review investigated how successful children/adolescents with poor literacy skills learn a foreign language compared with their peers with typical literacy skills. Moreover, we explored whether specific characteristics related to participants, foreign language instruction, and assessment moderated scores on foreign language tests in this population. Overall, 16 studies with a total of 968 participants (poor reader/spellers: n = 404; control participants: n = 564) met eligibility criteria. Only studies focusing on English as a foreign language were available. Available data allowed for meta-analyses on 10 different measures of foreign language attainment. In addition to standard mean differences (SMDs), we computed natural logarithms of the ratio of coefficients of variation (CVRs) to capture individual variability between participant groups. Significant between-study heterogeneity, which could not be explained by moderator analyses, limited the interpretation of results. Although children/adolescents with poor literacy skills on average showed lower scores on foreign language phonological awareness, letter knowledge, and reading comprehension measures, their performance varied significantly more than that of control participants. Thus, it remains unclear to what extent group differences between the foreign language scores of children/adolescents with poor and typical literacy skills are representative of individual poor readers/spellers. Taken together, our results indicate that foreign language skills in children/adolescents with poor literacy skills are highly variable. We discuss the limitations of past research that can guide future steps toward a better understanding of individual differences in foreign language attainment of children/adolescents with poor literacy skills.

Decoding and word recognition in English as a native and a foreign language in students with and without dyslexia (English vs. Polish students)

We aimed to investigate the relationship between reading difficulties in native language (NL: Polish) and English as a foreign language in dyslexia in English and Polish students, respectively, and to develop a model of relations between NL phonological awareness, rapid automatized naming, verbal short-term memory, and reading in English. Thirteen English students with dyslexia (ED), 15 without (END) and 16 Polish students with dyslexia (PD) and 16 without (PND) participated. We found that dyslexic deficits and different phoneme-to-grapheme correspondence rules between Polish and English interfered with the accuracy and fluency of word and nonword decoding and word recognition. Whereas END scored higher than PD and PND in all reading measures, ED did not, despite a NL advantage. When compared with PND, ED performed equal in nonword decoding, which depends to a higher degree on phoneme-to-grapheme conversion rather than lexical access. When compared with PD, ED performed equally in nonword fluency, which is most likely a nonscript-dependant skill. More variance in reading was explained by NL than FL factors, even if analogical NL/FL skills predicted a given variable. While in ED and END, these relationships agreed with the literature; in PD and PND, NL phonological awareness was not beneficial for English as a foreign language reading.

Are children with developmental dyslexia all the same? A cluster analysis with more than 300 cases

Reading is vital to every aspect of modern life, exacerbated by reliance of the internet, email, and social media on the written medium. Developmental dyslexia (DD) characterizes a disorder in which the core deficit involves reading. Traditionally, DD is thought to be associated with a phonological impairment. However, recent evidence has begun to suggest that the reading impairment in some individuals is provoked by a visual processing deficit. In this paper, we present WISC-IV data from more than 300 Italian children with a diagnosis of DD to investigate the manifestation of phonological and visual subtypes. Our results indicate the existence of two clusters of children with DD. In one cluster, the deficit was more pronounced in the phonological component, while both clusters were impaired in visual processing. These data indicate that DD may be an umbrella term that encompasses different profiles. From a theoretical perspective, our results demonstrate that dyslexia cannot be explained in terms of an isolated phonological deficit alone; visual impairment plays a crucial role. Moreover, general rather than specific accounts of DD are discussed.

Training RAN or reading? A telerehabilitation study on developmental dyslexia

Rehabilitation procedures recommended for developmental dyslexia (DD) are still not fully defined, and only few studies directly compare different types of training. This study compared a training (Reading Trainer) working on the reading impairment with one (Run the RAN) working on the rapid automatized naming (RAN) impairment, one of the main cognitive deficits associated with DD. Two groups of DD children (N = 45) equivalent for age, sex, full IQ, and reading speed were trained either by Reading Trainer (n = 21) or by Run the RAN (n = 24); both trainings required an intensive home exercise, lasting 3 months. Both trainings showed significant improvements in reading speed and accuracy of passages and words. Bypassing the use of alphanumeric stimuli, but empowering the cognitive processes underlying reading, training RAN may be a valid tool in children with reading difficulties opening new perspectives for children with severe impairments or, even, at risk of reading difficulties.

NL reading skills mediate the relationship between NL phonological processing skills and a foreign language (FL) reading skills in students with and without dyslexia: a case of a NL (Polish) and FL (English) with different degrees of orthographic consistency

The aim of our study was to examine the relationship between NL (Native Language: Polish) phonological processing skills (verbal and phonological short-term memory, phoneme segmentation and blending, rapid automatised naming (RAN)) and the accuracy and fluency of NL and English as a Foreign Language (EFL) word and nonword decoding and word recognition skills of Polish students with and without dyslexia. Sixty-three (45%) high school and junior high school students with and 78 (55%) without dyslexia participated. We found that dyslexia, years of studying EFL at school and privately, NL phoneme blending and RAN predicted word reading accuracy in EFL, and dyslexia, years of studying EFL privately, and NL RAN predicted EFL word reading fluency. Dyslexia and NL phoneme blending predicted the accuracy, and NL RAN-the fluency of EFL nonword decoding. These findings confirm that difficulties in FL acquisition result from NL phonological processing deficits, characteristic of dyslexia. Our results also showed relationships between NL phonological processing and EFL reading that were analogical to the ones observed for NL. The pattern of relations between NL phonological processing, NL reading, and EFL reading was similar for reading fluency, but not for reading accuracy in the compared groups. Both NL phonological processing and NL reading facilitated EFL reading, though it was more conspicuous in the control group, which suggests that readers with dyslexia benefit less from their NL reading skills when learning to read in FL.

Auditive training effects from a dichotic listening app in children with dyslexia

Dichotic listening (DL) taps information on the brain's language laterality, processing, and attention. Research has shown that DL responses in dyslexia deviate from the typical pattern. Here, effects of DL training and its correspondence to rapid naming (RAN) and digit span (DS) in typical children and children with dyslexia were assessed. Three groups of third graders participated: two training groups, control training (CT) and dyslexia training (DT), and a control group that received no training (control no training, CnT). All took part in testing pretraining and posttraining. DL measures were on laterality, response scores, and attention. The three groups showed different response patterns: minor changes in CnT, change in all measures in CT, and some changes in DT. RAN and DS scores correlated significantly with some of the DL measures, especially with the attention scores. Our findings support arguments that brain architecture for language in dyslexia is lateralised in the same way as in children without dyslexia. However, the ability to modulate attention during DL is weaker in dyslexia than in typically developing children. A training-induced normalisation of lateralisation was observed in free recall in the dyslexia group, which suggests that DL training may be a promising intervention approach.

Early Predictors of Learning a Foreign Language in Pre-school - Polish as a First Language, English as a Foreign Language

When a foreign language (FL) acquisition begins in preschool, at which time young learners are particularly linguistically sensitive, it allows for a higher FL competence in future. Moreover, a second language learning depends on a learner’s aptitude. The aim of our study was to assess the early predictors of learning English as a Foreign Language (EFL) in Polish pre-school students who had not yet started formal literacy instruction, and to characterize the level of their oral receptive and active skills in English. 30 children aged between 3 years 5 months and 5 years 10 months who attended two private and one state kindergarten, participated in the study. All were native speakers of Polish, and apart from English classes, communicated in their first language at kindergarten and in their everyday life. Non-verbal intelligence, emerging literacy, phonological awareness in Polish, and knowledge of English were assessed. We found that in Polish pre-school children emerging letter identification from their first language alphabet, phonological awareness in their first language, and non-verbal intelligence were related to the achievements in learning EFL, despite the differences in transparency between the two languages. Moreover, the children’s passive color vocabulary was larger than their active vocabulary, and they were used to repetition tasks. The participants in our study attempted to communicate in English during the assessment, which suggests that even at a pre-school age they were able to differentiate between first language and FL discourse. We also identified some problems possibly stemming from linguistic transfer, like articles omissions. Therefore, teachers should pay more emphasis to the differences between the first and the second language, in terms of: syntax, morphology, phonetics, phonology, and orthography, to prevent later consolidation of early errors. The automatisation of correct linguistic habits in young learners would equip them with skills for their later FL educational success.

Reading without words or target detection? A re-analysis and replication fMRI study of the Landolt paradigm

The Landolt paradigm is a visual scanning task intended to evoke reading-like eye-movements in the absence of orthographic or lexical information, thus allowing the dissociation of (sub-) lexical vs. visual processing. To that end, all letters in real word sentences are exchanged for closed Landolt rings, with 0, 1, or 2 open Landolt rings as targets in each Landolt sentence. A preliminary fMRI block-design study (Hillen et al. in Front Hum Neurosci 7:1-14, 2013) demonstrated that the Landolt paradigm has a special neural signature, recruiting the right IPS and SPL as part of the endogenous attention network. However, in that analysis, the brain responses to target detection could not be separated from those involved in processing Landolt stimuli without targets. The present study presents two fMRI experiments testing the question whether targets or the Landolt stimuli per se, led to the right IPS/SPL activation. Experiment 1 was an event-related re-analysis of the Hillen et al. (Front Hum Neurosci 7:1-14, 2013) data. Experiment 2 was a replication study with a new sample and identical procedures. In both experiments, the right IPS/SPL were recruited in the Landolt condition as compared to orthographic stimuli even in the absence of any target in the stimulus, indicating that the properties of the Landolt task itself trigger this right parietal activation. These findings are discussed against the background of behavioural and neuroimaging studies of healthy reading as well as developmental and acquired dyslexia. Consequently, this neuroimaging evidence might encourage the use of the Landolt paradigm also in the context of examining reading disorders, as it taps into the orientation of visual attention during reading-like scanning of stimuli without interfering sub-lexical information.

L1 and L2 reading skills in Dutch adolescents with a familial risk of dyslexia

BACKGROUND

The present study investigated differences in reading and spelling outcomes in Dutch and English as a second language (ESL) in adolescents with a high familial risk of dyslexia, of whom some have developed dyslexia (HRDys) while others have not (HRnonDys), in comparison to a low familial risk control group without dyslexia (LRnonDys). This allowed us to investigate the persistence of dyslexia in the first language (L1) and the effect of dyslexia on the second language (L2), which has, in this case, a lower orthographic transparency. Furthermore, the inclusion of the HRnonDys group allowed us to investigate the continuity of the familial risk of dyslexia, as previous studies observed that the HRnonDys group often scores in between the HRDys and LRnonDys group, and whether these readers without reading deficits in Dutch, have more reading difficulties in ESL.

METHODS

The data of three groups of adolescents were analyzed; 27 LRnonDys, 25 HRdys 25 HRnonDys. The mean age was 14;1 years; months, and 37 were male. All were native speakers of Dutch, attended regular secondary education (grade 7-10), and were non-native speakers of English. Using MANOVA the groups were compared on Dutch and English word reading fluency (WRF), spelling and vocabulary, Dutch pseudoword and loanword reading fluency, phonological awareness (PA), rapid automatized naming (RAN), and verbal short term and working memory. A repeated measures ANOVA was used to compare English and Dutch WRF, spelling and vocabulary directly within the three groups.

RESULTS

The analyses revealed that the HRDys group had a deficit in both reading and spelling in Dutch and ESL. They also performed poorer than the LRnonDys group on all other measures. Effect sizes were especially large for pseudoword reading and the reaction times during the PA task. The HRnonDys group scored generally poorer than the LRnonDys group but this difference was only significant for Dutch pseudoword reading, PA reaction times and verbal short term memory. In general the HRDys and HRnonDys group scored similar in Dutch and English, except for English WRF where the HRDys group scored slightly better than expected based on their Dutch WRF.

DISCUSSION

There was a high persistence of dyslexia. Adolescents with dyslexia had large impairments in reading and spelling, and reading related measures, both in Dutch and ESL. Despite high inter-individual differences, an overall three-step pattern was observed. Adolescents in the HRnonDys group scored in between the HRDys and LRnonDys group, supporting the polygenetic origin of dyslexia and the continuity of the familial risk of dyslexia. The lower orthographic transparency did not have a negative effect on L2 reading, spelling and vocabulary, both in the HRnonDys and HRDys group. The latter group performed slightly better than expected in L2, which may be a result of the massive exposure to English and high motivation to use English by adolescents.