Shifted phase of EEG cross-frequency coupling in individuals with Phelan-McDermid syndrome.
Michael G Mariscal, Elizabeth Berry-Kravis, Joseph D Buxbaum and 15 others
PMID 33910615WHAT IT FOUND
Children with Phelan-McDermid syndrome showed a shifted timing of brain waves compared to typically developing peers.
This neural difference did not correlate with their autism severity or sensory issues, but it did track with repetitive behaviours like insistence on sameness and rituals.
Key findings
01Individuals with Phelan-McDermid syndrome had significantly different alpha-gamma phase bias compared to typically developing controls, specifically over posterior brain regions.
02Within the Phelan-McDermid group, stronger coupling between brain frequencies was associated with higher scores for repetitive behaviours, particularly those related to sameness, rituals, and compulsions.
03Brain wave phase differences were not associated with general autism severity, social functioning, or sensory processing scores.
STILL TO COME
How it was doneWhat they foundWhat it means for OTs
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What it does not show
Small sample size (26 PMS, 15 TD) limits statistical power, particularly for subgroup analyses. Behavioral measures in the PMS group suffered from floor effects due to severity, making it difficult to detect subtle associations. The typically developing group did not undergo the same clinical assessments, so associations between neural metrics and behaviour could not be tested in controls. EEG was recorded while watching a movie, which may not reflect resting-state or task-specific network dynamics. The study is cross-sectional; it cannot determine if the neural differences cause the behaviours or vice versa.
Declared interests
Funding was provided by the National Institutes of Health, the Phelan-McDermid Syndrome Foundation, the William Randolph Hearst Foundation, and the Child Neurology Foundation. No other conflicts of interest are declared in the provided text.
The easy way to misread this
Do not interpret the association between brain coupling and repetitive behaviours as evidence that a treatment targeting these behaviours will normalize the EEG pattern. The study is cross-sectional and shows correlation, not causation, and the neural metric is not currently a validated clinical tool for monitoring therapy progress.