Linear and Non-linear Analyses of EEG in a Group of ASD Children During Resting State Condition

Abstract

This study analyses the spontaneous electroencephalogram (EEG) brain activity of 14 children diagnosed with Autism Spectrum Disorder (ASD) compared to 18 children with normal development, aged 5-11 years. (i) Power Spectral Density (PSD), (ii) variability across trials (coefficient of variation: CV), and (iii) complexity (multiscale entropy: MSE) of the brain signal analysis were computed on the resting state EEG. PSD (0.5-45 Hz) and CV were averaged over different frequency bands (low-delta, delta, theta, alpha, low-beta, high-beta and gamma). MSE were calculated with a coarse-grained procedure on 67 time scales and divided into fine, medium and coarse scales. In addition, significant neurophysiological variables were correlated with behavioral performance data (Kaufman Brief Intelligence Test (KBIT) and Autism Spectrum Quotient (AQ)). Results show increased PSD fast frequency bands (high-beta and gamma), higher variability (CV) and lower complexity (MSE) in children with ASD when compared to typically developed children. These results suggest a more variable, less complex and, probably, less adaptive neural networks with less capacity to generate optimal responses in ASD children.

Keywords: Autism spectrum disorder; Multiscale entropy; Power spectral density; Resting-state; Variability.

Fig. 1

Localization and collapse of electrodes by regions. The colors indicate the nine defined scalp areas for electrodes collapse

Fig. 2

Logarithm of the Power Spectral Density (LPSD) in control and ASD subjects

Fig. 3

Multiscale Entropy (MSE) for 67 scales in control and ASD subjects. The medium scale is highlighted to differentiate the three types of scales

Fig. 4

A Spearman Correlation between MSE (67 scales) and relative PSD (0.5–45 Hz) in control and ASD subjects. B Partial Spearman Correlation controlled for age (in days) for both groups of subjects. Significant cutoff values for each correlation (with FDR correction) are indicated in the graphs. In this correlation, we calculated up to a total of 67 scales to observe the effect of correlation with increasing scales