31057
Heterogeneity in Alpha Rhythm Modulation in School-Aged Children with and without Autism Spectrum Disorder (ASD): Results from the ABC-CT Interim Analysis
Objectives: To contrast alpha modulation in children with ASD versus typical development in response to point-light biological motion and to explore its relationship with clinical characteristics. The examination of alpha modulation may be instrumental in understanding neural atypicalities that affect how children with ASD process and understand the social world around them.
Methods: Participants were children with ASD (n=105) and typically developing (TD) controls (n=55) aged 6-11 (Table 1). ASD diagnoses were confirmed using the Autism Diagnostic Observation Schedule (ADOS-2) and the Autism Diagnostic Interview (ADI-R). Parents completed the Social Responsiveness Scale (SRS-2), a validated 65-item measure of social impairment in natural settings. Participants viewed a biological motion (biomotion) paradigm in which point-light displays (PLDs) of a human walking versus scrambled motion were presented randomly in four blocks of 26 trials (1025-1200 ms fixation crosshair followed by the 1000 ms stimulus). Alpha modulation was calculated as the difference in alpha power between the baseline fixation crosshair condition and the biomotion stimulus at central, frontal, and occipital electrode clusters over both hemispheres.
Results: Alpha modulation did not correlate with parent-reported social function (SRS-2) or ASD symptom severity (ADOS-2 Calibrated Severity Score; CSS) in TD males and males with ASD. However, in females with ASD (n=23), CSS correlated with alpha modulation over frontal (r=-0.469, p=0.024) and occipital (r=-0.443, p=0.034) regions, and SRS-2 scores correlated with alpha modulation over central (r=-0.444, p=0.039) and frontal (r=-0.496, p=0.019) regions. Correlations indicated that increased frontal, occipital, and central alpha modulation was associated with lower ASD symptomatology in females with ASD. In TD females (n=21), SRS-2 scores were positively correlated with alpha modulation over central (r=0.485, p=0.026) and frontal (r=0.439, p=0.047) regions, indicating that increased modulation was associated with greater social impairment. CSS correlates were not examined in TD females due to insufficient variation caused by floor effects.
Conclusions: Preliminary results suggest that alpha modulation during biological motion perception is distinct in males versus females with ASD and in females with and without ASD. However, females with and without ASD show opposing directionality and distinct scalp topography in the relationship between alpha modulation and social function. These results suggest that alpha modulation may offer a useful tool to understand phenotypic heterogeneity associated with sex differences in ASD.