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Introduction:Contrary to Diagnostic and Statistical Manual of Mental Disorders (DSM-5), fifth edition, some studies indicate that ADHD-inattentive presentation (ADHD-I) is a distinct diagnostic disorder and not an ADHD presentation.Methods:In this study, 12 ADHD-combined presentation (ADHD-C), 10 ADHD-I, and 13 controls were enrolled and their resting state EEG recorded. Following this, a graph theoretical analysis was performed and functional integration and segregation of brain network was calculated.Results:The results show that clustering coefficient of theta band was significantly different among three groups and significant differences were observed in theta global efficiency between controls and ADHD-C. Regarding the alpha band, a lower clustering coefficient was observed in control subjects. In the beta band, clustering coefficient was significantly different between the control and children with ADHD-C and also between ADHD-I and ADHD-C. The clustering coefficient, in the subjects with ADHD-C, demonstrated a rapid decline and was significantly lower than the subjects with ADHD-I and control.Conclusion:Decreased clustering, in high thresholds, may be associated with hyperactivity while increased segregation in low thresholds with inattentiveness. A different functional network occurs in the ADHD-C brain that is consistent with several studies that have reported ADHD-I as a distinct disorder.

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Attention deficit hyperactivity disorder is a neurodevelopmental condition associated with varying levels of hyperactivity, inattention, and impulsivity. This study investigates brain function in children with attention deficit hyperactivity disorder using measures of nonlinear dynamics in EEG signals during rest. During eyes-closed resting, 19 channel EEG signals were recorded from 12 ADHD and 12 normal age-matched children. We used the multifractal singularity spectrum, the largest Lyapunov exponent, and approximate entropy to quantify the chaotic nonlinear dynamics of these EEG signals. As confirmed by Wilcoxon rank sum test, largest Lyapunov exponent over left frontal-central cortex exhibited a significant difference between ADHD and the age-matched control groups. Further, mean approximate entropy was significantly lower in ADHD subjects in prefrontal cortex. The singularity spectrum was also considerably altered in ADHD compared to control children. Evaluation of these features was performed by two classifiers: a Support Vector Machine and a Radial Basis Function Neural Network. For better comparison, subject classification based on frequency band power was assessed using the same types of classifiers. Nonlinear features provided better discrimination between ADHD and control than band power features. Under four-fold cross validation testing, support vector machine gave 83.33% accurate classification results.

Pictures are often used in studies on memory, perception, and language; normative data are thus needed for such visual stimuli. In the present study, we aimed to obtain normative data for a set of 272 black-and-white pictures from middle-aged and elderly Persian speakers. A total of 206 volunteers were divided into two groups: a middle-aged (40-59 years old) group and an elderly (60 years old and over) group. The groups had similar characteristics in terms of education. Norms for every picture were developed to provide measures of name agreement, image agreement, conceptual familiarity, age of acquisition, and visual complexity. The results revealed that all of these measures vary with age, except for conceptual familiarity.

Neurofeedback training (NFT) is an effective intervention in regulating electroencephalogram (EEG) abnormalities leading to improvements in behavioral deficits, which exist in children with reading disabilities. This single-subject study explores our evaluation of the improvements in the reading ability and phonological awareness deficit, as well as the changes in the EEG in children with reading disabilities as a result of NFT. Participants were 6 children, aged between 8 and 10 years, who completed twenty 30-minute sessions of NFT and follow-up measurement sessions 2 months subsequent to the completion of the training sessions. The results showed significant improvement in reading and phonological awareness skills. Furthermore, EEG analysis did not show notable changes in the power of the targeted bands (delta, theta, and beta), rather there was normalization of coherence of the theta band at T3-T4, delta band at Cz-Fz, and beta band at Cz-Fz, Cz-Pz, and Cz-C4. These significant changes in coherence possibly indicate integration of sensory and motor areas that explains the improvements in reading skills and phonological awareness.

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