ASD is characterized by atypical developmental organization of neural signal complexity across temporal scales, with children with ASD exhibiting significantly higher multiscale entropy than typically developing peers, with group differences most pronounced in preschool-aged children and associated with autism symptom severity in frontal and parietal regions.
Key Findings
Results
Children with ASD exhibited significantly higher multiscale entropy (MSE) than typically developing (TD) children across brain regions and temporal scales.
Resting-state EEG was recorded from 186 children aged 3–11 years, including children with ASD and TD peers.
MSE was computed across 20 temporal scales to characterize neural signal complexity.
Group differences in MSE were observed broadly across brain regions and temporal scales in the full sample.
Participants were categorized into preschool-aged and school-aged groups to examine developmental differences.
Results
Group differences in MSE between ASD and TD children were most pronounced in preschool-aged children, while in school-aged children differences were more restricted to lower temporal scales and frontoparietal regions.
Preschool-aged children showed broader and more pronounced ASD versus TD group differences in MSE.
In school-aged children, ASD-TD differences were more restricted to lower temporal scales and frontoparietal regions.
This developmental pattern suggests a narrowing or regionalization of complexity differences as children age.
Results
In TD children, MSE increased robustly with age across temporal scales, while age-related associations in ASD were more variable and region-specific.
TD children showed a robust positive association between age and MSE across scales.
In children with ASD, the relationship between age and MSE was more variable and dependent on brain region.
These findings indicate atypical developmental trajectories of neural signal complexity in ASD compared to typical development.
Results
Individual differences in MSE were associated with autism symptom severity, particularly in frontal and parietal regions.
Associations between MSE and autism symptom severity were identified at the individual level.
Frontal and parietal regions showed the strongest associations between MSE and symptom severity.
This suggests that neural signal complexity in frontoparietal networks may be relevant to the behavioral and clinical profile of ASD.
Discussion
ASD is conceptualized in this study as a condition involving atypical developmental organization of large-scale neural dynamics, underscoring the importance of a multiscale developmental perspective.
Prior EEG studies in ASD have largely focused on spectral power and connectivity rather than signal complexity.
MSE across 20 temporal scales was used to capture complexity at multiple timescales simultaneously.
The authors argue that a multiscale developmental perspective is necessary for understanding neural dynamics in autism.
The findings support characterizing ASD by atypical developmental organization rather than a static group difference.
What This Means
This research suggests that children with autism spectrum disorder (ASD) have measurably different brain signal patterns compared to typically developing children, specifically in terms of neural 'complexity'—how irregular and varied the brain's electrical activity is over time. Using EEG (a non-invasive method to measure electrical activity in the brain) in 186 children aged 3–11, the researchers found that children with ASD consistently showed higher neural complexity than their typically developing peers across multiple brain regions and timescales. This difference was largest in younger, preschool-aged children, and became more focused on specific brain regions (particularly the front and back of the brain) and shorter timescales as children got older.
The study also found that in typically developing children, neural complexity increases steadily with age, suggesting a normal developmental process of brain maturation. In children with ASD, however, this age-related increase was much less consistent and varied depending on the brain region, indicating that the usual trajectory of brain development is altered in ASD. Additionally, the degree of neural complexity in certain brain regions was linked to the severity of autism symptoms in individual children, pointing to a potential biological marker related to clinical presentation.
This research suggests that measuring how complex brain signals are—across multiple timescales—could be a valuable tool for understanding how autism affects brain development. Rather than a single static brain difference, ASD appears to involve an atypical developmental path for how the brain's activity becomes organized over childhood, which could have implications for how and when interventions targeting brain development might be most effective.
Han J, Liang L, Song R, Zhang X, Liu J, Jiang G, et al.. (2026). Atypical Age-Related Patterns of Neural Signal Complexity in Autism Spectrum Disorder.. CNS neuroscience & therapeutics. https://doi.org/10.1002/cns.71173