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OBJECTIVES: The four studies in this thesis examine the central auditory pathways in children with hearing loss (HL) through recording event-related potentials (ERP) and mismatch negativity (MMN). The design of the project is partly experimental, and it also includes an intervention part and a follow-up-study after three years. The primary aims were the following: I. Explore whether a multi-feature paradigm (Optimum-1) for eliciting MMN could characterise difficulties in perceiving small sound contrasts in children with HL using their hearing aids (HAs) or cochlear implants (CIs) (Paper I). II. Investigate whether a computer-assisted reading intervention programme with a phonics approach (GraphoGame) could affect ERP and MMN in children with HL using HAs (Paper II) and CIs (Paper III). III. Examine the developmental changes of ERP and MMN over time (three years) among children with HL using HAs or CIs (Paper IV). METHODS: In total, children with HL (n=30) using HAs (n=15) or CIs (n=15), as well as a reference group of children with normal hearing (NH) (n=16), participated. All children were approximately 5–8 years old at baseline (the first ERP recording session), and 8–11 years old at the follow-up after three years. Paper I includes all participants at baseline. Paper II (children with HAs) and Paper III (children with CIs) are the intervention part: one month of repeatedly training with a computer-assisted reading intervention programme with a phonics approach (GraphoGame) and involve two ERP recording sessions: before and after the training. Paper IV comprises the follow-up study after three years and includes all three groups: the children using HAs, the children with CIs, and the children with NH. All studies are based on ERP recordings that, including the data processing, were identical for each of the three sessions. The ERP-recordings followed the multi-feature paradigm, Optimum-1. Thus, a standard stimulus alternated among five different deviants (gap, int

Objectives: The primary aim was to examine how event-related potentials (ERPs) and mismatch negativity (MMN) change and develop over time among children with hearing loss (HL) using hearing aids (HAs) or cochlear implants (CIs). Children with normal hearing (NH) were tested as a reference group. Methods: This three-year follow-up study included 13 children with sensorineural HL (SNHL); 7 children using bilateral HAs and 6 children using CIs; and 10 children with NH as a reference group. ERPs were recorded at baseline and after three years. At time for the original study the children were approximately 5-8 years old and at the follow-up study 8-11 years old. ERP recordings and data processing were identical in both sessions. A standard stimulus alternated with five different deviants (gap, intensity, pitch, location and duration), presented in a pseudorandom sequence, thus following the multi-feature paradigm, Optimum-1. MMN was calculated from the average ERP of each deviant minus the standard stimuli. Repeated measures ANOVA was used for the statistical analyses and the results were based on samples within a specific time interval; 80-224 ms. Results: There was a statistically significant difference in the obligatory responses between the NH and HA groups at baseline, but this difference disappeared after three years in our follow-up study. The children with HA also showed a significant difference in mean ERP at baseline compared to follow-up, and significant differences between the deviants at follow-up but not at baseline. This suggests an improvement over time among the children with HAs. On the other hand, the children with CIs did not differ from the NH children at baseline, but after three years their mean ERP was significantly lower compared to both the children with HA and NH, indicating a reduced development of the central auditory system in this age span among the children with CIs. Regarding MMN, there was an interaction between the duration deviant and

Objectives: The primary aim was to find out whether a computer-assisted reading intervention program with a phonic approach can affect event-related (ERPs) and mismatch negativity (MMN) in hearing impaired (HI) children using cochlear implants (CIs). Methods: This study involved a test group of 15 HI children with CIs and a control group of 14 normal hearing (NH) children. The children were 4 years and 10 months to 8 years and 1 month old. ERPs were recorded immediately before and after 4 weeks of training with a computer-assisted reading intervention, GraphoGame. A multi-feature paradigm, Optimum-1, was used, i.e. a standard stimulus alternated with five different deviants: gap intensity, pitch, location and duration. MMN was calculated from the mean amplitude ERP of each deviant minus the standard stimulus response in a specific time interval, 80 - 224 ms. Repeated measures ANOVA was used for the statistical analysis. Results: The results did not show any significant changes with the computerassisted training in the ERPs and MMNs among the HI children with CIs. The presence of both MMN and a positive mismatch response (pMMR), which might reflect an immaturity, complicates interpreting the results in this age group. Individually, there was a mix of MMNs and pMMRs among all participants, pre and post training, and the change of each deviant after intervention was not predictable. Conclusions: There are no significant changes in ERP or MMN after intervention, however lack of significances must be interpreted with caution. Besides the presence of both MMNs and pMMRs, only modest changes are to be expected on an individual basis and small samples hinder making statistical conclusions regarding the training's effects. The study contributes to some more descriptive pieces of ERPs and MMNs among the HI children with CIs. The issues of MMN and pMMR are highlighted.

OBJECTIVES: The primary aim was to investigate whether computer-assisted reading intervention somehow can affect event-related potentials (ERP) and mismatch negativity (MMN) in hearing impaired (HI) children with hearing aids (HAs) and normal hearing (NH) children. METHODS: The study included 15 HI children with sensorineural hearing loss (SNHL) using bilateral HAs and 14 NH children as a reference group; all children between the ages of 5 and 8. A multi-feature MMN-paradigm, Optimum-1, with a standard stimulus alternating with 5 different deviants was used. ERPs were recorded pre and post intervention, i.e. one month of repeatedly computer-assisted training (GraphoGame). MMN was calculated from the average ERP of each deviant minus standard. Data were based on samples within a specific time interval, 80-224 ms, and repeated measures ANOVA was used to analyze possible interactions. RESULTS: There was a significant difference between groups before training, though, the mean obligatory responses or MMN was not statistically significantly different before versus after training, neither among the NH nor the HI children. Further, the HI children did generally achieve lower levels in GraphoGame compared to the NH children. Altogether, our findings indicate differences between the groups and that training may affect the neurophysiological processing in the brain, gaining the HI children. Both MMN and positive mismatch response (pMMR) were seen among both the HA and NH children, irrespective to deviant type. Individually, changes of the MMN and pMMR after training seem unpredictable. CONCLUSION: There are statistically significant differences in both the obligatory responses in ERP and the MMNs between the NH and HI groups before the computer-assisted training. Though, these differences disappear after the intervention. This suggests possible training effects regarding the central auditory processing among the HI children.

Our aim was to explore whether a multi-feature paradigm (Optimum-1) for eliciting mismatch negativity (MMN) would objectively capture difficulties in perceiving small sound contrasts in children with hearing impairment (HI) listening through their hearing aids (HAs) and/or cochlear implants (CIs). Children aged 5-7 years with HAs, CIs and children with normal hearing (NH) were tested in a free-field setting using a multi-feature paradigm with deviations in pitch, intensity, gap, duration, and location. There were significant mismatch responses across all subjects that were positive (p-MMR) for the gap and pitch deviants (F(1,43) = 5.17, p = 0.028 and F(1,43) = 6.56, p = 0.014, respectively) and negative (MMN) for the duration deviant (F(1,43) = 4.74, p = 0.035). Only the intensity deviant showed a significant group interaction with MMN in the HA group and p-MMR in the CI group (F(2,43) = 3.40, p = 0.043). The p-MMR correlated negatively with age, with the strongest correlation in the NH subjects. In the CI group, the late discriminative negativity (LDN) was replaced by a late positivity with a significant group interaction for the location deviant. Children with severe HI can be assessed through their hearing device with a fast multi-feature paradigm. For further studies a multi-feature paradigm including more complex speech sounds may better capture variation in auditory processing in these children.

The present study explored nonword repetition (NWR) and nonword decoding in normalhearing (NH) children and in children with cochlear implants (CIs). Participants were 11 children with bilateral CIs, 5:0-7:11 years (M = 6.5 yrs.), and 11 NH children, individually age-matched to the children with CIs. The purpose was twofold; to thoroughly describe aspects of repetition and decoding of novel words and to study possible associations between them. All children were assessed after having practiced with a computer-assisted reading intervention with a phonics approach during four weeks. Results showed that NH children outperformed children with CIs on the majority of aspects of NWR. The analysis of syllable length in NWR revealed that children with CIs made more syllable omissions than did the NH children, and predominantly in prestressed positions. Additionally, the consonant cluster analysis showed significantly more consonant omissions and substitutions in children with CIs suggesting that reaching fine- grained levels of phonological processing was particularly difficult for these children. No significant difference was found for decoding accuracy between the groups, as measured by percent nonwords and percent phonemes correctly decoded, but differences were observed regarding error patterns. Further, phoneme deletions and lexicalizing of nonwords occurred more often in children with CIs than in those with NH. The correlation analysis revealed that the ability to repeat consonant clusters in NWR had the strongest associations to nonword decoding in both groups., This research was funded by The Swedish Research Council for Working Life and Social Sciences, the Linneaus Centers HEAD at Linkoping University, and CCL - Cognition, Communication and Learning at Lund University.

This study explored nonword repetition (NWR) and nonword decoding in normal-hearing (NH) children and in children with bilateral cochlear implants (CI). Participants were 11 children, with CI, 5:0-7:11 years (M = 6.5 years), and 11 NH children, individually age-matched to the children with CI. This study fills an important gap in research, since it thoroughly describes detailed aspects of NWR and nonword decoding and their possible associations. All children were assessed after having practiced with a computer-assisted reading intervention with a phonics approach during four weeks. Results showed that NH children outperformed children with CI on the majority of aspects of NWR. The analysis of syllable number in NWR revealed that children with CI made more syllable omissions than did the NH children, and predominantly in prestressed positions. In addition, the consonant cluster analysis in NWR showed significantly more consonant omissions and substitutions in children with CI suggesting that reaching fine-grained levels of phonological processing was particularly difficult for these children. No significant difference was found for nonword-decoding accuracy between the groups, as measured by whole words correct and phonemes correct, but differences were observed regarding error patterns. In children with CI phoneme, deletions occurred significantly more often than in children with NH. The correlation analysis revealed that the ability to repeat consonant clusters in NWR had the strongest associations to nonword decoding in both groups. The absence of as frequent significant associations between NWR and nonword decoding in children with CI compared to children with NH suggest that these children partly use other decoding strategies to compensate for less precise phonological knowledge, for example, lexicalizations in nonword decoding, specifically, making a real word of a nonword., AuthorCount:9

Objective: The purpose of the present study was to examine cognitive abilities (i.e., working memory (WM), lexical access, phonological processing skills (PhPS), and letter knowledge) in deaf and hard of hearing (D/HH) children in relation to a reference group with normal hearing (NH) children pre intervention with a computer-assisted program that focused on phonological coding. A more specific purpose was to explore how cognitive abilities were associated to PhPS pre intervention and to phonological change post intervention in D/HH children in general, and specifically in D/HH children with weak initial PhPS. Methods: Participants were thirty-two children using cochlear implants or hearing aids, or both in combination, and sixteen children with NH 5, 6 and 7 years of age. Children practiced with phonological coding 10 min per day for 4 weeks with support by their parents. Cognitive abilities were examined pre and post intervention. Results: NH and D/HH children displayed a similar performance level on the majority of cognitive tasks, but the D/HH children demonstrated weaker lexical access and PhPS. A significant correlation between complex WM and PhPS pre intervention was only observed in D/HH children. Weak initial performance on one phonological processing task capturing both lower level and higher level auditory processing was the main significant predictor of phonological change in all D/HH children. In D/HH children with weak initial PhPS letter naming was associated with phonological change. Conclusions: The associations between complex working memory and PhPS in D/HH children and the lack of such associations in children with NH may indicate that phonological processing skills require more cognitive resources in the D/HH children. Letter knowledge can act as a driving force for phonological change following intervention in D/HH children with weak PhPS.

Thirty-two children with hearing impairment (HI) using cochlear implants (CI) and/or hearing aids (HA), and sixteen with normal hearing (NH) participated in a computer-assisted intervention study that focused on perceiving and memorizing phonemic sounds. The first purpose was to study cognitive abilities in NH and HI children, how they related to phonological processing skills (PhPS) pre intervention and to phonological growth post intervention. The second purpose was to analyze children’s performance at different fine-grained levels of phonological processing, i.e. how they manipulated, stored and produced phonological entities of different size with or without semantic content. This was put in relation to children’s type of auditory stimulation (electrical; bilateral CI, bimodal: CI + HA and acoustical; bilateral HA). Results showed significant correlations between complex working memory and PhPS in children with HI but not in children with NH. This suggests different cognitive strategies in the children when dealing with phonological processing tasks. Poor phoneme discrimination was the strongest predictor of phonological growth in the children with HI as a function of training. Thus, the computer-assisted program was beneficial for HI children with weak initial phoneme discrimination skills. Children with CI showed reduced performance at fine-grained levels of receptive phonological processing but not on expressive phonological lexical tasks.

Children with mild to profound hearing impairment 5, 6 and 7 years of age, thirty-two using cochlear implants and/or hearing aids, and sixteen normal hearing children participated in a computer based phonological intervention study.The main design was a quasi-experimental design with three test sessions separated in time with four weeks. Each test session included tasks for phonological skills and letter knowledge. All children were asked to practice 10 minutes per day.Results showed that children with HI displayed a heterogeneous pattern of results with respect to phonological skills. Only 20 percent performed within the range of NH children; these were children with HA, except one child with CI/HA.Group comparisons at the first and last test session revealed that children with CI displayed difficulty with phonological working memory whereas children with HA showed less letter knowledge. Intervention revealed positive effects on accuracy of phoneme-grapheme correspondence for all children and a significant positive change on phonological processing skills for children with weak initial phonological skills., Barn med mild, måttlig och grav hörselnedsättning (HNS), i åldrarna 5, 6 och 7 år deltog i en datorbaserad fonologisk interventionsstudie. Trettiotvå barn använde cochleaimplantat (CI) och/eller hörapparat (HA). Sexton barn med normal hörsel utgjorde kontrollgrupp. Studien hade en kvasi-experimentell design med tre testtillfällen. Varje testtillfälle ägde rum med fyra veckors mellanrum och omfattade prövning av fonologiska färdigheter och bokstavskännedom. Alla deltagare informerades om att öva hemma 10 minuter per dag. Resultaten visade att barn med HNS uppvisade stor variation avseende fonologisk förmåga. Endast 20 procent presterade inom normalvariationen för normalhörande barn. Dessa var barn med HA, undantaget ett barn med CI/HA. Gruppjämförelser vid första och sista testtillfället visade att barn med CI uppvisade svårigheter med fonologiskt arbetsminne, medan barn med HA hade svagare bokstavskännedom. Interventionen visade generell effekt på säkerheten i fonem-grafemkorrespondens, och en signifikant positiv förändring avseende fonologisk bearbetningsförmåga hos barn med svagt initialt fonologiskt utgångsläge, Neurofysiologiska förutsättningar för hörande