31057
Heterogeneity in Alpha Rhythm Modulation in School-Aged Children with and without Autism Spectrum Disorder (ASD): Results from the ABC-CT Interim Analysis

Poster Presentation
Friday, May 3, 2019: 5:30 PM-7:00 PM
Room: 710 (Palais des congres de Montreal)
S. Kala1, A. Naples1, T. McAllister1, C. Carlos1, D. Stahl1, K. Chawarska1, G. Dawson2, R. Bernier3, S. Jeste4, C. A. Nelson5, S. J. Webb3, C. Sugar4, M. Murias6, F. Shic7,8, J. Dziura9, C. Brandt9 and J. McPartland1, (1)Child Study Center, Yale University School of Medicine, New Haven, CT, (2)Department of Psychiatry and Behavioral Sciences, Duke Center for Autism and Brain Development, Durham, NC, (3)Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, (4)University of California, Los Angeles, Los Angeles, CA, (5)Boston Children's Hospital, Boston, MA, (6)Duke Center for Autism and Brain Development, Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, (7)Center for Child Health, Behavior and Development, Seattle Children's Research Institute, Seattle, WA, (8)Pediatrics, University of Washington School of Medicine, Seattle, WA, (9)Yale University, New Haven, CT
Background: The alpha rhythm is oscillatory EEG activity in the 8-13 Hz frequency range originating from sensorimotor cortex. Alpha rhythm is suppressed when individuals execute motor action; such modulation in the absence of motor activity is inferred to represent mirror neuron system activity. There is mixed literature regarding atypical alpha rhythm in children with Autism Spectrum Disorder (ASD). The present study analyzed EEG response to point-light displays of biological motion to examine the relationship between alpha modulation and clinical presentation in ASD.

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.

See more of: Social Neuroscience
See more of: Social Neuroscience