Impact of Distractors on Sustained Attention and Inhibition in Children With ADHD.

OBJECTIVE: This study examines the impact of visual and auditory distractors on attention and inhibition in children with and without ADHD. METHOD: The study used the MOXO d-CPT child version. The sample consisted of 208 children aged 8 to 12 years, including 64 with ADHD and 144 controls. RESULTS: Children with ADHD and controls differed in their reaction to distracting stimuli; visual distractors cause a higher decrease in sustained attention and inhibitory control in the ADHD group. Moreover, auditory distractors generate improved performance in the control group but not in the ADHD group. In addition, age-related effects were found in both sustained attention and inhibitory control in all children, regardless of whether the ADHD condition was present. CONCLUSIONS: The findings indicate that children with ADHD performed poorer compared to controls, and that distractors differently affected the performance of the two groups.

A comparison of local-global visuospatial processing in autism spectrum disorder, nonverbal learning disability, ADHD and typical development.

BACKGROUND: Research on visuospatial functioning has revealed cognitive challenges for children with autism spectrum disorder (ASD), nonverbal learning disability (NLD) and attention deficit hyperactivity disorder (ADHD). These disorders are characterized by some overlapping symptoms, making their diagnosis a challenge. AIMS: The study aims to clarify the role of visuospatial abilities in their neuropsychological profiles by investigating different visuospatial domains and their interplay with the local-global processing. METHOD AND PROCEDURES: Participants (N = 150) with ASD, NLD, or ADHD were compared with typically-developing (TD) children on visuospatial processing speed, visuo-perceptual abilities, visuo-constructive abilities, and visuospatial working memory. Generalized mixed-effects models were performed and receiver operating characteristic curves were estimated to express the usefulness of a local-global processing index in discriminating groups. OUTCOMES AND RESULTS: The NLD group was impaired in all domains; children with ADHD revealed a heterogeneous profile, with greater impairments in visuospatial processing speed; ASD and TD groups were comparable. The local-global processing index had predictive power in discriminating among groups in visuo-constructive task. CONCLUSIONS AND IMPLICATIONS: The study of visuospatial abilities of children with ASD, NLD and ADHD might help to understand strengths and weaknesses in their neuropsychological profile and to differentiate between them. Clinical implications of these findings 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.

The lost children: The underdiagnosis of dyslexia in Italy. A cross-sectional national study.

BACKGROUND: Developmental dyslexia is one of the most common neurobehavioral disorders affecting children, but prevalence data on this condition are poor. The objective of the present study is to determine the prevalence of dyslexia in Italy in an unselected school population, using clearly defined diagnostic criteria and methods. METHODS: Cross-sectional study carried out in nine Italian Regions: two located in Northern Italy (Friuli Venezia Giulia and Veneto), three in Central Italy (Marche, Lazio and Umbria) and four in Southern Italy (Abruzzo, Molise, Puglia and Sardegna). Three consecutive levels of screening were carried out: the first two at school, to screen the population and identify children with suspect dyslexia; the last in centers with multi-professional staff specialized in learning disabilities to confirm the diagnosis. The key outcome measure is the prevalence of dyslexia, defined as the ratio between the number of children confirmed positive at the third level of screening and the total number of children enrolled in the study. RESULTS: We finally recruited 11094 children aged 8-10 years, of which 9964 constituted the final working sample after applying exclusion criteria and including only children who received parents' consent to participate. The prevalence of dyslexia in the whole sample was 3.5% (95% CI 3.2-3.9%), with little differences between Northern, Central and Southern Italy (respectively 3.6%, 3.2% and 3.7%). In almost two out of three children with dyslexia the disorder had not been previously diagnosed. CONCLUSIONS: This study confirms that in primary school children at the age of 8-10 years in Italy dyslexia is widely underestimated. Reliable data on dyslexia prevalence are needed to allocate necessary human and financial resources both to Health Services and Schools, ensuring timely support to children and families.

An Integrated Model of Executive Functioning is Helpful for Understanding ADHD and Associated Disorders.

OBJECTIVE: The aim of this study is to test the discriminative capacity of executive function (EF) tasks to better define the cognitive functioning of children with ADHD and comorbidities. METHOD: One hundred four children were presented with a battery of new EF tasks and a rating scale filled out by parents. RESULTS: Preliminary analysis of the neuropsychological tasks revealed the presence of five factors: Speed of Processing, Inhibition, Planning, Execution, and Retrospective Memory. All children with ADHD were impaired in Execution (a measure describing the capacity to achieve a goal). ADHD-only children were specifically impaired in Planning, while ADHD + reading disorder (RD) children were impaired in Speed of Processing and Retrospective Memory. Children with ADHD + oppositional defiant disorder (ODD) did not show impairment in any other EF domains. The five EF processes correlated with the EF Questionnaire. CONCLUSION: The present study describes different cognitive profiles in children with ADHD with or without comorbid disorders using neuropsychological EF measures.

The proposed changes for DSM-5 for SLD and ADHD: international perspectives--Australia, Germany, Greece, India, Israel, Italy, Spain, Taiwan, United Kingdom, and United States.

This article presents an international perspective of the proposed changes to the DSM-5 for learning disabilities (LD) and attention-deficit/hyperactivity disorders (ADHD) across ten countries: Australia, Germany, Greece, India, Israel, Italy, Spain, Taiwan, the United Kingdom, and the United States. We provide perspectives of the present situation for youth with LD and youth with ADHD and describe the legislation, prevalence rates, and educational systems that serve students with disabilities in the respective countries. We also present a discussion of the expected impact of the proposed changes for the diagnosis of LD and ADHD in each country.

The submerged dyslexia iceberg: how many school children are not diagnosed? Results from an Italian study.

BACKGROUND: Although dyslexia is one of the most common neurobehavioral disorders affecting children, prevalence is uncertain and available data are scanty and dated. The objective of this study is to evaluate the prevalence of dyslexia in an unselected school population using clearly defined and rigorous diagnostic criteria and methods. METHODS: Cross sectional study. We selected a random cluster sample of 94 fourth grade elementary school classes of Friuli Venezia Giulia, a Region of North Eastern Italy. We carried out three consecutive levels of screening: the first two at school and the last at the Neuropsychiatry Unit of a third level Mother and Child Hospital. The main outcome measure was the prevalence of dyslexia, defined as the number of children positive to the third level of screening divided by the total number of children enrolled. RESULTS: We recruited 1774 children aged 8-10 years, of which 1528 received parents' consent to participate. After applying exclusion criteria, 1357 pupils constituted the final working sample. The prevalence of dyslexia in the enrolled population ranged from 3.1% (95% CI 2.2-4.1%) to 3.2% (95% CI 2.4-4.3%) depending on different criteria adopted. In two out of three children with dyslexia the disorder had not been previously diagnosed. CONCLUSIONS: This study shows that dyslexia is largely underestimated in Italy and underlines the need for reliable information on prevalence, in order to better allocate resources both to Health Services and Schools.

Cortical reorganization in dyslexic children after phonological training: evidence from early evoked potentials.

Brain plasticity was investigated in 14 Italian children affected by developmental dyslexia after 6 months of phonological training. The means used to measure language reorganization was the recognition potential, an early wave, also called N150, elicited by automatic word recognition. This component peaks over the left temporo-occipital cortex and its amplitude depends on linguistic expertise. N150 elicited by written words was measured both in dyslexic children before and after training and in a sample of matched normal readers during phonological, semantic and orthographic tasks. After training, dyslexic children increased their reading speed. Normal readers showed a typical left posterior N150, whereas in dyslexic children it was equally distributed across hemispheres before and shifted to left posterior sites after training. In addition, dyslexics' left posterior N150 asymmetry on the phonological task after training was significantly correlated with reading speed improvement, that is, those children who showed the greatest left shift in phonological N150 also had the greatest reading speed improvement. Source localization of the N150 component was made with both the Standard Low Resolution Electromagnetic Tomography software and the classical dipole analysis method termed Brain Electrical Source Analysis. The N150 generator lies in the left occipito-temporal cortex (Brodmann areas 39, 37 and 19) in good readers, but in right homologous areas in dyslexic children before training. After the treatment, the dyslexics' main N150 generator shifted to the left occipito-inferotemporal cortex (namely Brodmann areas 37 and 19) with small differences between tasks. The two source location methods provided consistent, converging solutions. Results add to the current literature on the phonological hypothesis of dyslexia by showing hemispheric reorganization of linguistic networks at the level of early word recognition potential. Furthermore, the present work is the first to investigate brain reorganization in a regular/transparent language like Italian.

Brain plasticity in developmental dyslexia after phonological treatment: a beta EEG band study.

Linguistic EEG hemispheric reorganization was investigated in 14 dyslexic children after a 6-month phonological training (10 min/day through PC software). Error rates from three linguistic tasks significantly decreased and reading speed improved after the training. A significant positive correlation (r(12)=0.536) was found at posterior sites for the phonological task only, showing that those children who had the greatest reading speed enhancement showed the largest left posterior EEG beta power increase.

Contrasting deficits on executive functions between ADHD and reading disabled children.

BACKGROUND: The object of this study was to analyze the executive functioning of children with attention deficit hyperactivity disorder (ADHD) or reading disability (RD) independent of their non-executive deficits. METHODS: Three carefully diagnosed groups of children, aged between 7 and 12 years (35 ADHD, 22 RD and 30 typically developing children), were tested on a wide range of tasks related to five major domains of executive functioning (EF): inhibition, visual working memory, planning, cognitive flexibility, and verbal fluency. Additional tasks were selected for each domain to control for non-executive processing. RESULTS: ADHD children were impaired on interference control, but not on prepotent and ongoing response suppression. ADHD showed deficits on visual working memory, planning, cognitive flexibility and phonetic fluency. RD children were impaired on phonetic fluency. The only EF measure that differentiated ADHD from RD was planning. CONCLUSIONS: The present sample of ADHD children showed several EF deficits, whereas RD children were almost spared executive dysfunction, but exhibited deficits in phonetic fluency.

Efficacy of an intervention to improve fluency in children with developmental dyslexia in a regular orthography.

The purpose of this study was to examine the efficacy of a method to improve reading fluency in children with dyslexia. The method, which we named "subsyllabic," was aimed at automatizing the recognition of syllables within words in connected texts, presented by ad hoc software. Two versions of this method--one self-paced and the other one with automatic syllable identification-were compared to a method based on phonemic awareness, assisted reading, and other psycholinguistic exercises. The efficacy of the two versions of the subsyllabic method was further studied by repeating the first version twice and the second version three times using an AB design, with each phase lasting approximately 3 months. This part of the study provided not only follow-up data but also useful information on if and how fluency may change after repeated treatment. Outcomes obtained by a total of 63 children with dyslexia suggested that the subsyllabic method was superior to the control method and that the use of an automatic presentation of target syllables produced better results. Furthermore, we observed that fluency improved approximately at the same rate after each treatment repetition. Our data support the possibility of improving reading fluency at a significant clinical level, at least for regular orthographies. The crucial component of the subsyllabic method seems to be the facilitation of syllable recognition within words in connected texts and the emphasis on their rapid recognition using an automatized procedure.

Evidence for a double dissociation between spatial-simultaneous and spatial-sequential working memory in visuospatial (nonverbal) learning disabled children.

The paper describes the performance of three children with specific visuospatial working memory (VSWM) impairments (Study 1) and three children with visuospatial (nonverbal) learning disabilities (Study 2) assessed with a battery of working memory (WM) tests and with a number of school achievement tasks. Overall, performance on WM tests provides evidence of a double dissociation between spatial-simultaneous processes, underpinning the memorization item positioning in a spatial configuration, and spatial-sequential processes, which allow memorization of the presentation order. In both groups of children of the two studies, a selective impairment either on spatial-sequential or on spatial-simultaneous working memory tasks was observed. These data support the existence of -simultaneous and -sequential modality-dependent processes in visuospatial working memory and confirm the importance of distinguishing between different subtypes of visuospatial (nonverbal) learning-disabled children.

Altered hemispheric asymmetry during word processing in dyslexic children: an event-related potential study.

The present event-related potential study aimed at finding neurophysiological correlates of inadequate reading performances in developmental dyslexia. By using the same set of words in different linguistic tasks, we found variations of cortical asymmetry between dyslexic individuals and controls starting with the N420, a component supposed to index the phonological processing during reading. Whereas in controls this component was left lateralized, in disabled readers it was more distributed across hemispheres. The observed lack of lateralization in dyslexic individuals was also found in the later slow negative wave that developed in the 700 to 1500-ms time interval. We postulate that the altered asymmetry is related to an impairment of the grapheme-phoneme conversion mechanism. The findings would therefore support the hypothesis of a phonological deficit underlying this learning disability.