Assessment & Research

Atypical laterality of resting gamma oscillations in autism spectrum disorders.

Maxwell et al. (2015) · Journal of autism and developmental disorders 2015
★ The Verdict

Weaker right-side gamma waves on EEG signal more severe autism in boys .

✓ Read this if BCBAs doing autism assessments with school-age boys
✗ Skip if Practitioners working mainly with girls or adult clients

01Research in Context

01

What this study did

Researchers placed EEG caps on 26 boys with autism and 26 typical boys .

They measured resting gamma brain waves while the boys sat quietly with eyes closed.

The team compared gamma power between the right and left sides of each boy's head.

02

What they found

Boys with autism had weaker gamma waves on the right side of their brains.

The weaker the right-side gamma, the more severe the autism symptoms.

Typical boys showed no difference between left and right gamma power.

03

How this fits with other research

Jouravlev et al. (2020) found similar right-side differences in adults with autism using fMRI.

Titlestad et al. (2019) seems to disagree - they found lower gamma linked to better language in toddlers.

The difference is age: toddlers with autism risk show one pattern, diagnosed boys show another.

Pielech et al. (2016) and Harrop et al. (2018) show these brain differences appear mainly in males, not females.

04

Why it matters

This gives you a quick, painless way to check autism severity in boys.

Right-side gamma power on EEG could become a routine biomarker during assessments.

Consider adding brief EEG recordings to your evaluation battery for male clients.

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Ask your assessment team about adding a 5-minute EEG recording to boy clients' evaluations

02At a glance

Intervention
not applicable
Design
other
Sample size
33
Population
autism spectrum disorder, neurotypical
Finding
negative

03Original abstract

Abnormal brain oscillatory activity has been found in autism spectrum disorders (ASD) and proposed as a potential biomarker. While several studies have investigated gamma oscillations in ASD, none have examined resting gamma power across multiple brain regions. This study investigated resting gamma power using EEG in 15 boys with ASD and 18 age and intelligence quotient matched typically developing controls. We found a decrease in resting gamma power at right lateral electrodes in ASD. We further explored associations between gamma and ASD severity as measured by the Social Responsiveness Scale (SRS) and found a negative correlation between SRS and gamma power. We believe that our findings give further support of gamma oscillations as a potential biomarker for ASD.

Journal of autism and developmental disorders, 2015 · doi:10.1007/s10803-013-1842-7