Patterns of spontaneous neural activity associated with social communication abilities among infants and toddlers showing signs of autism

Abstract

Early disruptions to social communication development, including delays in joint attention and language, are among the earliest markers of autism spectrum disorder (autism, henceforth). Although social communication differences are a core feature of autism, there is marked heterogeneity in social communication-related development among infants and toddlers exhibiting autism symptoms. Neural markers of individual differences in joint attention and language abilities may provide important insight into heterogeneity in autism symptom expression during infancy and toddlerhood. This study examined patterns of spontaneous electroencephalography (EEG) activity associated with joint attention and language skills in 70 community-referred 12- to 23-month-olds with autism symptoms and elevated scores on an autism diagnostic instrument. Data-driven cluster-based permutation analyses revealed significant positive associations between relative alpha power (6-9 Hz) and concurrent response to joint attention skills, receptive language, and expressive language abilities. Exploratory analyses also revealed significant negative associations between relative alpha power and measures of core autism features (i.e., social communication difficulties and restricted/repetitive behaviors). These findings shed light on the neural mechanisms underlying typical and atypical social communication development in emerging autism and provide a foundation for future work examining neural predictors of social communication growth and markers of intervention response.

Keywords: autism; electroencephalography; infancy; joint attention; language.

Figure 1.

Cluster-based permutation analyses revealed a significant positive association between response to joint attention (RJA) and relative alpha power, as seen in two clusters involving right frontotemporal areas (Cluster 1, p = .021, depicted with + symbols) and left frontotemporal/parietal areas (Cluster 2, p = .050, depicted with x symbols). Scatterplots depict the relationship between RJA and relative alpha power within significant clusters (calculated by summing alpha power values across channels comprising each cluster).

Figure 2.

Cluster-based permutation analyses revealed significant positive associations between language ability and relative alpha power. Topographical plots, left, depict clusters of electrodes significantly positively associated with language ability; areas shown in bright yellow are regions where this relationship is strongest. Scatterplots depict the relationship between language ability and relative alpha power within significant clusters (calculated by summing alpha power values across channels comprising each cluster). A. Receptive Language: Relative alpha power is significantly, positively associated with receptive language DQ scores, as seen in two independent clusters involving left frontotemporal/occipital regions (Cluster 1, p = .031, depicted with + symbols) and right frontotemporal regions (Cluster 2, p = .036, depicted with x symbols). B. Expressive Language: Relative alpha power is significantly, positively associated with expressive language DQ scores (p = .006). The significant cluster is depicted in the topographical plot with + symbols.

Figure 3.

Cluster-based permutation analyses revealed significant negative associations between ADOS-2 domain scores (indexing social communication impairments and restricted/repetitive behaviors) and relative alpha power, suggesting that children who exhibited increased spontaneous relative alpha power tended to have lower levels of autism symptoms. Regions shown in bright yellow are areas where the negative association was strongest. A. ADOS-2 Social Affect. Relative alpha power is significantly, negatively associated with levels of social communication-related autism symptoms, as seen in clusters involving right frontotemporal areas (Cluster 1, p = .031, depicted with + symbols) and left parietal areas (Cluster 2, p = .043, depicted with x symbols). B. ADOS-2 RRB. Relative alpha power is significantly, negatively associated with RRB features of autism, as seen in a single cluster involving the left temporoparietal region (p = .029, depicted with + symbols).