Genetics of developmental dyslexia

Developmental dyslexia is a highly heritable disorder with a prevalence of at least 5% in school-aged children. Linkage studies have identified numerous loci throughout the genome that are likely to harbour candidate dyslexia susceptibility genes. Association studies and the refinement of chromosomal translocation break points in individuals with dyslexia have resulted in the discovery of candidate genes at some of these loci. A key function of many of these genes is their involvement in neuronal migration. This complements anatomical abnormalities discovered in dyslexic brains, such as ectopias, that may be the result of irregular neuronal migration

Evaluation of an online version of the CFT 20-R in third and fourth grade children

There is growing demand for digital intelligence testing. In the current study, we evaluated the validity of an online version of the revised German Culture Fair Intelligence Test (CFT 20-R). A total of 4100 children from the third and fourth grades completed the online version using a smartphone or tablet. Subsequently, 220 of these children also completed the paper-pencil (PP) version. The internal consistency and construct validity of the online version appeared to be acceptable. The correlation between the raw scores and school grades in German and mathematics was slightly lower than expected. On average, the raw scores for the PP version were revealed to be higher, which was probably due to a learning effect. At the item level, the results show small differences for the subtests Series and Matrices, possibly caused by small differences in the presentation of the items. The correspondence between the versions did not depend on children’s levels of impulsivity or intelligence. Altogether, the results support the hypothesis that the online version of the CFT 20-R is a valid measure of general fluid intelligence and highlight the need for separate norms. (DIPF/Orig.

The KOALA-study: study protocol for a comprehensive study of cognitive biases in adolescent anorexia nervosa patients compared to healthy and clinical controls

BACKGROUND Anorexia nervosa (AN) is characterized by dysfunctional cognitions including cognitive biases at various levels of information processing. However, less is known about the specificity of these biases, i.e., if they occur for eating-disorder-related information alone or also for non-eating-disorder-related emotional information in AN patients (content-specificity) and if they are unique to individuals with AN or are also shown by individuals with other mental disorders (disorder-specificity). METHODS The present study systematically assesses cognitive biases in 12-18-year-old female adolescents with AN on three levels of information processing (attention, interpretation, and memory) and with regard to two types of information content (eating-disorder-related, i.e., stimuli related to body weight and shape, and non-eating-disorder-related). To address not only content- but also disorder-specificity, adolescents with AN will be compared not only to a healthy control group but also to a clinical control group (adolescents with major depression or particular anxiety disorders). Cognitive biases are assessed within a single experimental paradigm based on the Scrambled Sentences Task. During the task eye movements are recorded in order to assess attention biases while interpretation biases are derived from the behavioural outcome. An incidental free recall test afterwards assesses memory biases. We expect adolescents with AN to show more pronounced negative cognitive biases on all three levels of information processing and for both types of content compared to healthy adolescents. In addition, we expect the specificity of biases to translate into differential results for the two types of content: AN patients are expected to show stronger biases for disorder-related stimuli but similar or less pronounced biases for non-disorder-related stimuli compared to the clinical control group. DISCUSSION This is the first study to comprehensively assess cognitive biases in adolescents with AN. It will have essential implications not only for cognitive-behavioural models of AN but also for subsequent studies aiming to modify cognitive biases in this population, thereby addressing important maintaining factors already at an early stage of the disorder

Entwicklungsstörungen schulischer Fertigkeiten

Der Beitrag gibt einen Überblick über den in der Kinder- und Jugendpsychiatrie, der Psychologie und der Sonderpädagogik erbrachten Forschungsstand zu Lernstörungen, die im klinischen Diagnosemanual der Weltgesundheitsorganisation als „Entwicklungsstörungen schulischer Fertigkeiten“ bezeichnet werden. Der Leser wird mit den allgemeinen Definitionen und Kriterien des Bereiches vertraut gemacht sowie mit den Beurteilungskriterien, Einschränkungen und aktuellen Prävalenzschätzungen. Für die Lese-Rechtschreibstörung, die Rechenstörung sowie für die kombinierten Störungen schulischer Fertigkeiten werden der aktuelle Forschungsstand zu Prävalenz, Ursachen, Diagnostik und effektiver Prävention bzw. Intervention dargestellt. (DIPF/Orig.

What does the brain of children with developmental dyslexia tell us about reading improvement? ERP evidence from an intervention study

Intervention is key to managing developmental dyslexia (DD), but not all children with DD benefit from treatment. Some children improve (improvers, IMP), whereas others do not improve (non-improvers, NIMP). Neurobiological differences between IMP and NIMP have been suggested, but studies comparing IMP and NIMP in childhood are missing. The present study examined whether ERP patterns change with treatment and differ between IMP and NIMP. We investigated the ERPs of 28 children with DD and 25 control children (CON) while performing a phonological lexical decision (PLD) task before and after a 6-month intervention. After intervention children with DD were divided into IMP (n = 11) and NIMP (n = 17). In the PLD-task children were visually presented with words, pseudohomophones, pseudowords, and false fonts and had to decide whether the presented stimulus sounded like an existing German word or not. Prior to intervention IMP showed higher N300 amplitudes over fronto-temporal electrodes compared to NIMP and CON and N400 amplitudes were attenuated in both IMP and NIMP compared to CON. After intervention N300 amplitudes of IMP were comparable to those of CON and NIMP. This suggests that the N300, which has been related to phonological access of orthographic stimuli and integration of orthographic and phonological representations, might index a compensatory mechanism or precursor that facilitates reading improvement. The N400, which is thought to reflect grapheme-phoneme conversion or the access to the orthographic lexicon increased in IMP from pre to post and was comparable to CON after intervention. Correlations between N300 amplitudes pre, growth in reading ability and N400 amplitudes post indicated that higher N300 amplitudes might be important for reading improvement and increase in N400 amplitudes showing the same cognitive profile might differ regarding their neuronal profile which could further influence reading improvement

The time course of reading processes in children with and without dyslexia: an ERP study

The main diagnostic criterion for developmental dyslexia (DD) in transparent orthographies is a remarkable reading speed deficit, which is often accompanied by spelling difficulties. These deficits have been traced back to both deficits in orthographic and phonological processing. For a better understanding of the reading speed deficit in DD it is necessary to clarify which processing steps are degraded in children with DD during reading. In order to address this question the present study used EEG to investigate three reading related ERPs: the N170, N400 and LPC. Twenty-nine children without DD and 52 children with DD performed a phonological lexical decision (PLD)-task, which tapped both orthographic and phonological processing. Children were presented with words, pseudohomophones, pseudowords and false fonts and had to decide whether the presented stimulus sounded like an existing German word or not. Compared to control children, children with DD showed deficits in all the investigated ERPs. Firstly, a diminished mean area under the curve for the word material-false font contrasts in the time window of the N170 was observed, indicating a reduced degree of print sensitivity; secondly, N400 amplitudes, as suggested to reflect the access to the orthographic lexicon and grapheme-phoneme conversion, were attenuated; and lastly, phonological access as indexed by the LPC was degraded in children with DD. Processing differences dependent on the linguistic material in children without DD were observed only in the LPC, suggesting that similar reading processes were adopted independent of orthographic familiarity. The results of this study suggest that effective treatment should include both orthographic and phonological training. Furthermore, more longitudinal studies utilizing the same task and stimuli are needed to clarify how these processing steps and their time course change during reading development

Deficits in Letter-Speech Sound Associations but Intact Visual Conflict Processing in Dyslexia: Results from a Novel ERP-Paradigm

The reading and spelling deficits characteristic of developmental dyslexia (dyslexia) have been related to problems in phonological processing and in learning associations between letters and speech-sounds. Even when children with dyslexia have learned the letters and their corresponding speech sounds, letter-speech sound associations might still be less automatized compared to children with age-adequate literacy skills. In order to examine automaticity in letter-speech sound associations and to overcome some of the disadvantages associated with the frequently used visual-auditory oddball paradigm, we developed a novel electrophysiological letter-speech sound interference paradigm. This letter-speech sound interference paradigm was applied in a group of 9-year-old children with dyslexia (n = 36) and a group of typically developing (TD) children of similar age (n = 37). Participants had to indicate whether two letters look visually the same. In the incongruent condition (e.g., the letter pair A-a) there was a conflict between the visual information and the automatically activated phonological information; although the visual appearance of the two letters is different, they are both associated with the same speech sound. This conflict resulted in slower response times (RTs) in the incongruent than in the congruent (e.g., the letter pair A-e) condition. Furthermore, in the TD control group, the conflict resulted in fast and strong event-related potential (ERP) effects reflected in less negative N1 amplitudes and more positive conflict slow potentials (cSP) in the incongruent than in the congruent condition. However, the dyslexic group did not show any conflict-related ERP effects, implying that letter-speech sound associations are less automatized in this group. Furthermore, we examined general visual conflict processing in a control visual interference task, using false fonts. The conflict in this experiment was based purely on the visual similarity of the presented objects. Visual conflict resulted in slower RTs, less negative N2 amplitudes and more positive cSP in both groups. Thus, on a general, basic level, visual conflict processing does not seem to be affected in children with dyslexia

Increased hippocampal shape asymmetry and volumetric ventricular asymmetry in autism spectrum disorder

Autism spectrum disorder (ASD) is a prevalent and fast-growing pervasive neurodevelopmental disorder worldwide. Despite the increasing prevalence of ASD and the breadth of research conducted on the disorder, a conclusive etiology has yet to be established and controversy still exists surrounding the anatomical abnormalities in ASD. In particular, structural asymmetries have seldom been investigated in ASD, especially in subcortical regions. Additionally, the majority of studies for identifying structural biomarkers associated with ASD have focused on small sample sizes. Therefore, the present study utilizes a large-scale, multi-site database to investigate asymmetries in the amygdala, hippocampus, and lateral ventricles, given the potential involvement of these regions in ASD. Contrary to prior work, we are not only computing volumetric asymmetries, but also shape asymmetries, using a new measure of asymmetry based on spectral shape descriptors. This measure represents the magnitude of the asymmetry and therefore captures both directional and undirectional asymmetry. The asymmetry analysis is conducted on 437 individuals with ASD and 511 healthy controls using T1-weighted MRI scans from the Autism Brain Imaging Data Exchange (ABIDE) database. Results reveal significant asymmetries in the hippocampus and the ventricles, but not in the amygdala, in individuals with ASD. We observe a significant increase in shape asymmetry in the hippocampus, as well as increased volumetric asymmetry in the lateral ventricles in individuals with ASD. Asymmetries in these regions have not previously been reported, likely due to the different characterization of neuroanatomical asymmetry and smaller sample sizes used in previous studies. Given that these results were demonstrated in a large cohort, such asymmetries may be worthy of consideration in the development of neurodiagnostic classification tools for ASD