ABSTRACT
Gamma oscillations have been associated with early language development in typically developing toddlers, and gamma band abnormalities have been observed in individuals with ASD, as well high-risk infant siblings (those having an older sibling with autism), as early as 6-months of age. The current study investigated differences in baseline frontal gamma power and its association with language development in toddlers at high versus low familial risk for autism. EEG recordings as well as cognitive and behavioral assessments were acquired at 24-months as part of prospective, longitudinal study of infant siblings of children with and without autism. Diagnosis of autism was determined at 24–36 months, and data was analyzed across three outcome groups - low risk without ASD (n=43), high-risk without ASD (n=42), and high-risk with ASD (n=16). High-risk toddlers without ASD had reduced baseline frontal gamma power (30–50Hz) compared to low-risk toddlers. Among high-risk toddlers increased frontal gamma was only marginally associated with ASD diagnosis (p=0.06), but significantly associated with reduced expressive language ability (p=0.007). No association between gamma power and language was present in the low-risk group. These findings suggest that differences in gamma oscillations in high-risk toddlers may represent compensatory mechanisms associated with improved developmental outcomes.
Author Contributions:
CLW was involved in study conception, performed the EEG and behavioral data analysis, interpreted the data, and drafted the manuscript. ARL and LJGD contributed to EEG preparation and analysis, and critically revised the manuscript for intellectual content. HTF and CAN were responsible for the study design, overseeing data acquisition, and critically reviewed the manuscript for intellectual content.
Acknowledgements
We thank all the families and staff who were involved in this study. We also thank Adriana Sofia Mendez Leal and Michael Mariscal for contributing code used in EEG analysis.
This research was Support for this work was provided by: The National Institutes of Health (R01-DC010290 to HTF and CAN; R21 DC 08637 to HTF; 1T32MH112510 to CLW), Autism Speaks (1323 to HTF), Simons Foundation (137186 to CAN), FRAXA Research Foundation (CLW), American Brain Foundation (ARL), Autism Science Foundation (ARL, CLW) and Nancy Lurie Marks Family Foundation (ARL). Statistical analysis was conducted with support from Harvard Catalyst | The Harvard Clinical and Translational Science Center (National Center for Advancing Translational Sciences, National Institutes of Health Award UL1 TR001102) and financial contributions from Harvard University and its affiliated academic healthcare centers. The content is solely the responsibility of the authors and does not necessarily represent the official views of Harvard Catalyst, Harvard University and its affiliated academic healthcare centers, or the National Institutes of Health. The above funding bodies did not have any role in the design, collection, analyses, or interpretation of the data or in writing this manuscript.
Footnotes
Conflict of Interest Statement: The authors declare that they have no conflicts of interest
ABBREVIATIONS
- ADHD
- : Attention Deficit Hyperactivity Disorder
- ADOS
- : Autism Diagnostic Observation Schedule
- ASD
- : Autism Spectrum Disorder
- BEAPP
- : Batch EEG Automated Processing Platform
- EEG
- : Electroencephalography
- HAPPE
- : Harvard Automated Preprocessing Pipeline for EEG
- HR-ASD
- : High-risk with ASD
- HR-NoASD
- : High-risk without ASD
- LR
- : Low-risk without ASD
- MARA
- : Multiple Artifact Rejection Algorithm
- MSEL
- : Mullen Scales of Early Learning
- PDDST-II
- : Pervasive Developmental Disorders Screening Test-II PV: parvalbumin
- SCQ
- : Social Communication Questionnaire