Inter-trial theta phase consistency during face processing in infants is associated with later emerging autism.
Messy 3–6 Hz theta brain waves while looking at faces at 6–10 months forecast autism by age three.
01Research in Context
What this study did
van Noordt et al. (2022) watched 6- to 10-month-old babies look at pictures of faces. The team used a stretchy baby cap with tiny EEG sensors. They measured how steady the babies' 3–6 Hz theta brain waves were from one picture to the next.
All babies had an older sibling with autism, so they were at high risk. The researchers waited until each child turned three. Then they checked who got an autism diagnosis and who did not.
What they found
Babies who later received an ASD label had messier theta rhythms. Their brain waves did not line up well when the same face appeared again. Typical-risk babies kept a steady beat.
The difference showed up only during the late part of face viewing, when the brain usually fine-tunes recognition.
How this fits with other research
van Noordt et al. (2017) saw the same theta misfire, but in teenagers doing a reward game. Together, the two studies say theta timing stays off across the whole autism lifespan.
Eussen et al. (2016) used fMRI and found slower amygdala habituation to fearful faces in older youth with ASD. The infant EEG and adult fMRI results line up: faces never quite feel familiar to the autism brain.
Papageorgopoulou et al. (2024) watched high-risk babies at 8 and 14 months. Those who later got an ASD diagnosis already showed flatter parent-infant play. Pair the social-behavior dip with the theta-timing dip and you get a two-track early warning system.
Why it matters
You can’t strap an EEG cap on every baby in clinic, but you can keep an eye on siblings. When you see a 9-month-old who rarely locks faces with mom, think about a referral for a short EEG visit. A theta-timing check could add a cheap, five-minute biomarker to your early-screen toolkit. More data before age one means earlier parent coaching and less guesswork later.
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02At a glance
03Original abstract
A growing body of research suggests that consistency in cortical activity may be a promising neurophysiological marker of autism spectrum disorder (ASD). In the current study we examined inter-trial coherence, a measure of phase consistency across trials, in the theta range (t-ITC: 3-6 Hz), as theta has been implicated in the processing of social and emotional stimuli in infants and adults. The sample included infants who had an older sibling with a confirmed ASD diagnosis and typically developing (TD) infants with no family history of ASD. The data were collected as part of the British Autism Study of Infant Siblings (BASIS) study. Infants between 6 and 10 months of age (Mage = 7.34, SDage = 1.21) performed a visual face processing task that included faces and scrambled, "face noise", stimuli. Follow-up assessments in higher likelihood infants were completed at 24 and again at 36 months to determine diagnostic outcomes. Analysis focused on posterior t-ITC during early (0-200 ms) and late (200-500 ms) visual processing stages commonly investigated in infant studies. t-ITC over posterior scalp regions during late stage face processing was significantly higher in TD and higher likelihood infants without ASD (HRA-), indicating reduced consistency in theta-band responses in higher likelihood infants who eventually receive a diagnosis of ASD (HRA+). These findings indicate that the temporal dynamics of theta during face processing relate to ASD outcomes. Reduced consistency of oscillatory dynamics at basic levels of infant sensory processing could have downstream effects on learning and social communication. LAY SUMMARY: We examined the consistency in brain responses to faces in infants at lower or higher familial likelihood for autism. Our results show that the consistency of EEG responses was lower during face processing in higher likelihood infants who eventually received a diagnosis of autism. These findings highlight that reduced consistency in brain activity during face processing in the first year of life is related to emerging autism.
Autism research : official journal of the International Society for Autism Research, 2022 · doi:10.1002/aur.2701