Analysis of EEG signals in children with autism spectrum disorder under positive and negative emotional stimuli

Autism spectrum disorder (ASD, hereafter autism) is a neurodevelopmental disorder. The symptoms of autism, including the core features of social interaction and language communication disorders, repetitive stereotyped behaviors, and limited narrow interest, are most obvious in children 2-3 years old. Research also shows that childhood is the most critical period for autism diagnosis and behavioral intervention. Because emotional recognition ability is of great importance to individual social development, the emotional recognition defect of children with autism has an extremely negative impact on their social interaction ability, thus hindering their social development. Related studies indicate that, under different emotional stimuli, the occipital and temporal lobes of children with autism show a lower activation state, which affects the development of their social cognitive and emotional recognition abilities. An objective evaluation of the development of autistic children's brain function using an electroencephalogram (EEG) is feasible. This paper analyses testees' electroencephalograms of several encephalic regions, including frontal, temporal and occipital lobes, along with their emotional performance metrics and cognitive level to investigate the difference in autistic children and typically developing children's performance and electroencephalograms while they are being induced by videos designed to produce positive or negative emotions. Based on the emotional performance indicators obtained from brainwave power spectrums and cognitive questions, we analyzed the children's performance under two emotional stimuli. The experiment recruited 80 children, 40 autistic and 40 typically developing children. We processed the power spectrum analysis of testees' electroencephalograms through fast Fourier transform and explored the effects between the different groups. Our results show that autistic children's electroencephalograms generally show very high power in the low frequency range (delta, theta) and high frequency range (beta, gamma) but low power in the alpha band. Moreover, different encephalic regions show different features of the power spectrum. By comparing the testees' emotional performance metrics based on their electroencephalograms' power spectrums, as well as cognitive levels based on answering questions under two kinds of emotional stimulation, we found that autistic children's emotional changes are far less than those of typically developing children. In addition, autistic children's cognition of six aspects, such as emotional and spatial cognition, are both lower than that of typically developing children. Furthermore, under positive emotion conditions, they show more interest and higher engagement, and their correct rate of answering cognition questions is higher than under negative emotion conditions. This research provides an objective basis for intervention training that aims to improve autistic children's emotional cognitive levels.