Brain Source Correlates of Speech Perception and Reading Processes in Children With and Without Reading Difficulties

Neural correlates in reading and speech processing have been addressed extensively in the literature. While reading skills and speech perception have been shown to be associated with each other, their relationship remains debatable. In this study, we investigated reading skills, speech perception, reading, and their correlates with brain source activity in auditory and visual modalities. We used high-density event-related potentials (ERPs), fixation-related potentials (FRPs), and the source reconstruction method. The analysis was conducted on 12–13-year-old schoolchildren who had different reading levels. Brain ERP source indices were computed from frequently repeated Finnish speech stimuli presented in an auditory oddball paradigm. Brain FRP source indices were also computed for words within sentences presented in a reading task. The results showed significant correlations between speech ERP sources and reading scores at the P100 (P1) time range in the left hemisphere and the N250 time range in both hemispheres, and a weaker correlation for visual word processing N170 FRP source(s) in the posterior occipital areas, in the vicinity of the visual word form areas (VWFA). Furthermore, significant brain-to-brain correlations were found between the two modalities, where the speech brain sources of the P1 and N250 responses correlated with the reading N170 response. The results suggest that speech processes are linked to reading fluency and that brain activations to speech are linked to visual brain processes of reading. These results indicate that a relationship between language and reading systems is present even after several years of exposure to print

Neural correlates of speech and print processing in children with or without reading or attention deficits in native and foreign languages

Lukivaikeudet ja tarkkaavaisuushäiriöt ovat yleisimmin raportoituja oppimishäiriöitä kouluikäisillä lapsilla. Mittavasta tutkimuksesta huolimatta useisiin näiden oppimisvaikeuksien aivoperustaan liittyviin kysymyksiin ei olla vielä saatu vastausta. Tässä väitöskirjassa tutkitaan puheen prosessoinnin, visuaalisen lukemisen prosessoinnin ja auditiivisen tarkkaavaisuuden prosessoinnin neuraalisia korrelaatioita tyypillisesti kehittyneillä lapsilla ja lapsilla, joilla on lukemisen tai tarkkaavaisuusden vaikeuksia. Tutkimuksessa käytettiin aivovasteita (ERP), fiksaatiopotentiaaleja (FRP, silmänliikkeisiin aikasidottuja aivovasteita) ja aivoaktivaation lähdemallinnusmenetelmiä. Lisäksi tutkimuksessa käytettiin käyttäytymistason mittareita täydentämään aivojen tuottamaa tietoa. Tutkimuksessa I tutkittiin aivojen esitietoista erottelua mittaaviaprosesseja, poikkeavuusnegatiivisutta (MMR) ja myöhäistä erottelunegatiivisuutta (LDN) äidinkielen (suomi) ja vieraan kielen (englanti) puheärsykkeisiintyypillisesti kehittyneillä lapsilla (kontorlliryhmä, CTR, N=86) ja lapsilla, joilla oli lukemisen vaikeuksia (RD, N=26). Lukivaikeusryhmässä havaittiin epätyypilline erottelua heijastava aivovaste ollen suurentunut sekä äidinkielisiin että vieraskielisiin puheääniin. Lisäksi aivovasteet poikkesivat toisistaan äidinkielen ärsykkeisiin verrattuna vieraan puheen ärsykkeisiin kummassakin ryhmässä. Tutkimuksessa II tutkittiin puheen havaitsemiseen liittyviä aivojen perusvasteita ääniin (ns. P1-N250 komponenttia) ja niiden yhteyksiä lukemisen perusprosesseja heijastaviin visuaalisiin aivovasteisiin (ns. N170 komponenttiin) lähteen paikannusmallinnuksen avulla. Kuulotiedon ja puhetiedon käsittelyä heijastavien aivoaktivaatiolähteiden välillä havaittiin yhteyksiä. Aivojen ohimolohkon kuulo-ja puhealueiden aktivaatiolla oli selkeä yhteys sanantunnistusta heijastavaan aktivaatioon ohimo-ja takaraivolohkojen liittymäkohdan läheisyydessä olevalla ns. visuaalisella sanan tunnistamisalueella (VWFA). Lisäksi puheen prosessointia heijastava aktivaatio oli yhteydessälukutehtävässä suoriutumiseen. Tutkimuksessa III tutkittiin tahattoman huomion suuntaamista heijastavaa aivovastetta (ns. P3a) sekä äidin että vieraan kielen puheärsykkeisiintyypillisesti kehittyvillä lapsilla ja lapsilla, joilla oli tarkkaavaisuuden pulmai (N=17). Tulokset osoittivat, että P3a-vaste äidinkielisiin puheääniin erotteli ryhmiä ja oli yhteydessä tarkkaavaisuutta mittaaviin opettajan arviointeihin. Vieraan kielen prosessointia heijastavilla aivovasteilla ei havaittu olevan yhteyksiä tarkkaavaisuuteen. Tarkkaavaisuuden hermoverkkoa tutkittiin myös lähteenpaikannus analyysin avulla. Tarkkavaaisuuspulmaisten ryhmässä havaittiin suurentuneita aivovasteita sekä lähdeaktivaation että sensorien (päänpinnalta) mitattavien aivovasteiden tasolla. Kaiken kaikkiaan tämän väitöskirjan tulokset osoittivat eroja tyypillisesti kehittyvien lasten ja oppimisen vaikeuksista kärsivien lasten sekä eri kielisiä ärsykkeitä heijastavien aivovasteiden välillä.Reading difficulties (RD) and attentional problems (AP) are the most frequently reported learning disorders in school-aged children. Although extensive research has been conducted on the subject, several questions about the neural processes in these learning difficulties remain to be answered. This dissertation investigates neural correlates of speech processing, visual reading processing, and auditory attentional processing in typical children and in children with reading or attentional difficulties. High-density event-related potentials (ERPs), fixation-related potentials (FRPs), and source reconstruction methods were used. In addition, behavioral measures were used to complement the brain data. In Study I, discriminatory brain processes, the mismatch response (MMR), and the late discriminative negativity (LDN), were investigated in native (Finnish) and foreign (English) language contexts in typical children (CTR, N=86) and in children with RD (N=26). Atypical discriminatory responses with enhanced brain activity to native and foreign speech items were found in the RD group. Furthermore, in both groups, brain responses were different for the native language stimuli than for foreign speech stimuli. Study II investigated speech-perception-related obligatory responses (P1-N250), and early visual response in reading (N170). The results showed associations between brain activity in both modalities and brain activity with reading scores. The brain responses to speech reflected in the source activity of the temporal sources were found to be associated with the brain activity to print in the temporo-occipital areas. Furthermore, the brain activity for speech and print showed correlations with the reading scores. Study III investigated the involuntary attention brain response (P3a) in speech processing investigated, both in typical children and in children with AP (N=17), using native and foreign language stimuli. The results showed a group difference in the P3a response, and significant correlations between the attention score and the brain activity in the native context in both groups. No significant correlations were found in the foreign language context. The neural network of attention was also investigated, using source analysis. Enhanced brain responses were found in the AP group, both at the scalp and source levels. Overall, this dissertation investigated the temporal brain dynamics of different processes and their relationships and showed how they varied between different populations of children with and without learning disorders

Auditory P3a response to native and foreign speech in children with or without attentional deficit.

The aim of this study was to investigate the attentional mechanism in speech processing of native and foreign language in children with and without attentional deficit. For this purpose, the P3a component, cognitive neuromarker of the attentional processes, was investigated in a two-sequence two-deviant oddball paradigm using Finnish and English speech items via event-related potentials (ERP) technique. The difference waves reflected the temporal brain dynamics of the P3a response in native and foreign language contexts. Cluster-based permutation tests evaluated the group differences over the P3a time window. A correlation analysis was conducted between the P3a response and the attention score (ATTEX) to evaluate whether the behavioral assessment reflected the neural activity. The source reconstruction method (CLARA) was used to investigate the neural origins of the attentional differences between groups and conditions. The ERP results showed a larger P3a response in the group of children with attentional problems (AP) compared to controls (CTR). The P3a response differed statistically between the two groups in the native language processing, but not in the foreign language. The ATTEX score correlated with the P3a amplitude in the native language contrasts. The correlation analysis hint at some hemispheric brain activity difference in the frontal area. The group-level CLARA reconstruction showed activation in the speech perception and attention networks over the frontal, parietal, and temporal areas. Differences in activations of these networks were found between the groups and conditions, with the AP group showing higher activity in the source level, being the origin of the ERP enhancement observed on the scalp level

Auditory P3a response to native and foreign speech in children with or without attentional deficit

The aim of this study was to investigate the attentional mechanism in speech processing of native and foreign language in children with and without attentional deficit. For this purpose, the P3a component, cognitive neuromarker of the attentional processes, was investigated in a two-sequence two-deviant oddball paradigm using Finnish and English speech items via event-related potentials (ERP) technique. The difference waves reflected the temporal brain dynamics of the P3a response in native and foreign language contexts. Cluster-based permutation tests evaluated the group differences over the P3a time window. A correlation analysis was conducted between the P3a response and the attention score (ATTEX) to evaluate whether the behavioral assessment reflected the neural activity. The source reconstruction method (CLARA) was used to investigate the neural origins of the attentional differences between groups and conditions. The ERP results showed a larger P3a response in the group of children with attentional problems (AP) compared to controls (CTR). The P3a response differed statistically between the two groups in the native language processing, but not in the foreign language. The ATTEX score correlated with the P3a amplitude in the native language contrasts. The correlation analyses hint at some hemispheric brain activity difference in the frontal area. The group-level CLARA reconstruction showed activation in the speech perception and attention networks over the frontal, parietal, and temporal areas. Differences in activations of these networks were found between the groups and conditions, with the AP group showing higher activity in the source level, being the origin of the ERP enhancement observed on the scalp level.peerReviewe

Brain Source Correlates of Speech Perception and Reading Processes in Children With and Without Reading Difficulties.

Neural correlates in reading and speech processing have been addressed extensively in the literature. While reading skills and speech perception have been shown to be associated with each other, their relationship remains debatable. In this study, we investigated reading skills, speech perception, reading, and their correlates with brain source activity in auditory and visual modalities. We used high-density event-related potentials (ERPs), fixation-related potentials (FRPs), and the source reconstruction method. The analysis was conducted on 12-13-year-old schoolchildren who had different reading levels. Brain ERP source indices were computed from frequently repeated Finnish speech stimuli presented in an auditory oddball paradigm. Brain FRP source indices were also computed for words within sentences presented in a reading task. The results showed significant correlations between speech ERP sources and reading scores at the P100 (P1) time range in the left hemisphere and the N250 time range in both hemispheres, and a weaker correlation for visual word processing N170 FRP source(s) in the posterior occipital areas, in the vicinity of the visual word form areas (VWFA). Furthermore, significant brain-to-brain correlations were found between the two modalities, where the speech brain sources of the P1 and N250 responses correlated with the reading N170 response. The results suggest that speech processes are linked to reading fluency and that brain activations to speech are linked to visual brain processes of reading. These results indicate that a relationship between language and reading systems is present even after several years of exposure to print

Discriminatory Brain Processes of Native and Foreign Language in Children with and without Reading Difficulties

The association between impaired speech perception and reading difficulty has been well established in native language processing, as can be observed from brain activity. However, there has been scarce investigation of whether this association extends to brain activity during foreign language processing. The relationship between reading skills and neuronal speech representation of foreign language remains unclear. In the present study, we used event-related potentials (ERPs) with high-density EEG to investigate this question. Eleven- to 13-year-old children typically developed (CTR) or with reading difficulties (RD) were tested via a passive auditory oddball paradigm containing native (Finnish) and foreign (English) speech items. The change-detection-related ERP responses, the mismatch response (MMR), and the late discriminative negativity (LDN) were studied. The cluster-based permutation tests within and between groups were performed. The results showed an apparent language effect. In the CTR group, we found an atypical MMR in the foreign language processing and a larger LDN response for speech items containing a diphthong in both languages. In the RD group, we found unstable MMR with lower amplitude and a nonsignificant LDN response. A deficit in the LDN response in both languages was found within the RD group analysis. Moreover, we observed larger brain responses in the RD group and a hemispheric polarity reversal compared to the CTR group responses. Our results provide new evidence that language processing differed between the CTR and RD groups in early and late discriminatory responses and that language processing is linked to reading skills in both native and foreign language contexts

What information should I look for again? : Attentional difficulties distracts reading of task assignments

This large-scale eye-movement study (N = 164) investigated how students read short task assignments to complete information search problems and how their cognitive resources are associated with this reading behavior. These cognitive resources include information searching subskills, prior knowledge, verbal memory, reading fluency, and attentional difficulties. In this study, the task assignments consisted of four sentences. The first and last sentences provided context, while the second or third sentence was the relevant or irrelevant sentence under investigation. The results of a linear mixed-model and latent change score analyses showed the ubiquitous influence of reading fluency on first-pass eye movement measures, and the effects of sentence relevancy on making more and longer reinspections and look-backs to the relevant than irrelevant sentence. In addition, the look-backs to the relevant sentence were associated with better information search subskills. Students with attentional difficulties made substantially fewer look-backs specifically to the relevant sentence. These results provide evidence that selective look-backs are used as an important index of comprehension monitoring independent of reading fluency. In this framework, slow reading fluency was found to be associated with laborious decoding but with intact comprehension monitoring, whereas attention difficulty was associated with intact decoding but with deficiency in comprehension monitoring.peerReviewe

Discriminatory Brain Processes of Native and Foreign Language in Children with and without Reading Difficulties

The association between impaired speech perception and reading difficulty has been well established in native language processing, as can be observed from brain activity. However, there has been scarce investigation of whether this association extends to brain activity during foreign language processing. The relationship between reading skills and neuronal speech representation of foreign language remains unclear. In the present study, we used event-related potentials (ERPs) with high-density EEG to investigate this question. Eleven- to 13-year-old children typically developed (CTR) or with reading difficulties (RD) were tested via a passive auditory oddball paradigm containing native (Finnish) and foreign (English) speech items. The change-detection-related ERP responses, the mismatch response (MMR), and the late discriminative negativity (LDN) were studied. The cluster-based permutation tests within and between groups were performed. The results showed an apparent language effect. In the CTR group, we found an atypical MMR in the foreign language processing and a larger LDN response for speech items containing a diphthong in both languages. In the RD group, we found unstable MMR with lower amplitude and a nonsignificant LDN response. A deficit in the LDN response in both languages was found within the RD group analysis. Moreover, we observed larger brain responses in the RD group and a hemispheric polarity reversal compared to the CTR group responses. Our results provide new evidence that language processing differed between the CTR and RD groups in early and late discriminatory responses and that language processing is linked to reading skills in both native and foreign language contexts.Peer reviewe