title: Down syndrome's brain dynamics: analysis of fractality in resting state.
abstract: To the best knowledge of the authors there is no study on nonlinear brain dynamics of down syndrome (DS) patients, whereas brain is a highly complex and nonlinear system. In this study, fractal dimension of EEG, as a key characteristic of brain dynamics, showing irregularity and complexity of brain dynamics, was used for evaluation of the dynamical changes in the DS brain. The results showed higher fractality of the DS brain in almost all regions compared to the normal brain, which indicates less centrality and higher irregular or random functioning of the DS brain regions. Also, laterality analysis of the frontal lobe showed that the normal brain had a right frontal laterality of complexity whereas the DS brain had an inverse pattern (left frontal laterality). Furthermore, the high accuracy of 95.8 % obtained by enhanced probabilistic neural network classifier showed the potential of nonlinear dynamic analysis of the brain for diagnosis of DS patients. Moreover, the results showed that the higher EEG fractality in DS is associated with the higher fractality in the low frequencies (delta and theta), in broad regions of the brain, and the high frequencies (beta and gamma), majorly in the frontal regions.
authors.affiliation: Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Sahel
authors.initials: S
authors.lastname: Hemmati
authors.affiliation: Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran ; Dynamic Brain Research Group, Tehran, Iran ; Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.
authors.forename: Mehran
authors.initials: M
authors.lastname: Ahmadlou
authors.affiliation: Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Gharib
authors.affiliation: Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Roshanak
authors.initials: R
authors.lastname: Vameghi
authors.affiliation: Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran ; Dynamic Brain Research Group, Tehran, Iran.
authors.forename: Firoozeh
authors.initials: F
authors.lastname: Sajedi
keywords: Down syndrome; EEG; Fractal dimension