2019Alycia Halladay
Mirror mirror on the wall, what is the fairest early predictor of adult language ability?
Language development in children with autism spectrum disorder (ASD) varies greatly among affected individuals and is a strong predictor of later outcomes. Younger siblings of children with ASD have increased risk of ASD, but also language delay. Identifying neural markers of language outcomes in infant siblings could facilitate earlier intervention and improved outcomes. This study aimed to determine whether EEG measures from the first 2-years of life can explain heterogeneity in language development in children at low- and high-risk for ASD, and to determine whether associations between EEG measures and language development are different depending on ASD risk status or later ASD diagnosis. In this prospective longitudinal study EEG measures collected between 3-24 months were used in a multivariate linear regression model to estimate participants’ 24-month language development. Individual baseline longitudinal EEG measures included (1) the slope of EEG power across 3-12 months or 3-24 months of life for 6 canonical frequency bands, (2) estimated EEG power at age 6-months for the same frequency bands, and (3) terms representing the interaction between ASD risk status and EEG power measures. Modeled 24-month language scores using EEG data from either the first 2-years (Pearson R = 0.70, 95% CI 0.595-0.783, P=1×10-18) or the first year of life (Pearson R=0.66, 95% CI 0.540-0.761, P=2.5×10-14) were highly correlated with observed scores. All models included significant interaction effects of risk on EEG measures, suggesting that EEG-language associations are different depending on risk status, and that different brain mechanisms effect language development in low-versus high-risk infants.
Background: Delayed walking is common in intellectual disability (ID) but may be less common when ID occurs with autism spectrum disorder (ASD). Previous studies examining this were limited by reliance on clinical samples and exclusion of children with severe motor deficits.
Objective: To examine in a population-based sample if age of walking is differentially related to intellectual ability in children with ASD versus other neurodevelopmental disorders (NDD).
Methods: Participants were from the nested Autism Birth Cohort Study of the Norwegian Mother, Father and Child Cohort Study (MoBa). Cox proportional hazards regression assessed if diagnosis (ASD n = 212 vs. NDD n = 354), continuous nonverbal IQ, and their interaction, were associated with continuous age of walking.
Results: The relationship between nonverbal IQ and age of walking was stronger for NDD than for ASD (Group × nonverbal IQ interaction, χ2 = 13.93, p = .0002). This interaction was characterized by a 21% decrease in the likelihood of walking onset at any given time during the observation period per 10-point decrease in nonverbal IQ (hazard ratio = 0.79, 95% CI: 0.78-0.85) in the NDD group compared to 8% (hazard ratio = 0.92, 95% CI: 0.86-0.98) in the ASD group.
Conclusions: The finding that age of walking is less strongly related to low intellectual ability in children with ASD than in children without other NDDs supports the hypothesis that ID in ASD may result from heterogeneous developmental pathways. Late walking may be a useful stratification variable in etiological research focused on ASD and other NDDs.
Keywords: Intellectual disability; MoBa; epidemiology; gross motor milestones; late walking.
This study investigated early posture development prospectively in infants at heightened (HR) vs. low risk (Low Risk; LR) for ASD. Fourteen HR infants diagnosed with ASD (HR-ASD), 17 HR infants with language delay (HR-LD), 29 HR infants with no diagnosis (HR-ND), and 25 LR infants were videotaped at home for 25 min during everyday activities and play at 6, 8, 10, 12, and 14 months. All postures were coded and the sustainment source was identified for supported postures. Relative to LR infants, HR-ASD infants and to a lesser extent HR-LD infants exhibited distinct postural trajectories that revealed slower development of more advanced postures. In addition, subtle differences in posture sustainment differentiated HR-ASD from HR-LD infants.
Keywords: Autism spectrum disorder; Infant siblings; Motor development; Posture.