EEG hyper-connectivity in high-risk infants is associated with later autism.
BACKGROUND
It has been previously reported that structural and functional brain connectivity in individuals with autism spectrum disorders (ASD) is atypical and may vary with age. However, to date, no measures of functional connectivity measured within the first 2 years have specifically associated with a later ASD diagnosis.


METHODS
In the present study, we analyzed functional brain connectivity in 14-month-old infants at high and low familial risk for ASD using electroencephalography (EEG). EEG was recorded while infants attended to videos. Connectivity was assessed using debiased weighted phase lag index (dbWPLI). At 36 months, the high-risk infants were assessed for symptoms of ASD.


RESULTS
As a group, high-risk infants who were later diagnosed with ASD demonstrated elevated phase-lagged alpha-range connectivity as compared to both low-risk infants and high-risk infants who did not go on to ASD. Hyper-connectivity was most prominent over frontal and central areas. The degree of hyper-connectivity at 14 months strongly correlated with the severity of restricted and repetitive behaviors in participants with ASD at 3 years. These effects were not attributable to differences in behavior during the EEG session or to differences in spectral power.


CONCLUSIONS
The results suggest that early hyper-connectivity in the alpha frequency range is an important feature of the ASD neurophysiological phenotype.
Centre for Brain and Cognitive Development, School of Psychology, Birkbeck, University of London, Henry Welcome Building, London, WC1E 7HX UK.
Elena V
EV
Orekhova
Department of Psychiatry, McGill University, Montreal, PQ H3A 1A1 Canada.
Mayada
M
Elsabbagh
Centre for Brain and Cognitive Development, School of Psychology, Birkbeck, University of London, Henry Welcome Building, London, WC1E 7HX UK.
Emily Jh
EJ
Jones
Department of Psychiatry and Behavioral Sciences, School of Medicine, Duke University, Durham, NC 27705 USA.
Geraldine
G
Dawson
Department of Psychology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 8AF UK.
Tony
T
Charman
Centre for Brain and Cognitive Development, School of Psychology, Birkbeck, University of London, Henry Welcome Building, London, WC1E 7HX UK.
Mark H
MH
Johnson
Alpha; Autism spectrum disorders; Connectivity; EEG; Infants; Siblings