Fear Potentiated Startle in Children With Autism Spectrum Disorder: Association With Anxiety Symptoms and Amygdala Volume.
David Hessl, Lauren Libero, Andrea Schneider and 9 others
PMID 33372389WHAT IT FOUND
Children with autism showed the same fear-potentiated startle response as typically developing peers, regardless of anxiety diagnosis.
This physiological measure did not track anxiety severity, suggesting it is not a reliable biomarker for anxiety in this population.
Key findings
01Fear-potentiated startle was similar in the ASD and TD groups, with no significant main effect of group.
02There was no significant association between fear-potentiated startle and overall, traditional, or autism-distinct anxiety severity in the ASD group.
03Amygdala volume moderated the relationship between fear-potentiated startle and anxiety, but this finding is exploratory due to limited MRI data and small sample size.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
A high proportion of children with ASD (26 of 48 analyzed plus others excluded) could not complete the protocol or provide valid data, primarily due to noisy data or noncompliance. Those who failed to provide valid data had significantly lower IQs, meaning the results may not generalize to children with ASD and intellectual disability. Anxiety assessment relied entirely on caregiver reports, which may miss internal experiences or misinterpret behaviors. The sample size was limited, particularly for MRI analyses, reducing statistical power. The study used only one type of conditioned stimulus and unconditioned stimulus, which may not capture the full range of anxiety triggers in ASD.
Declared interests
The study was supported by the National Institute of Mental Health (NIMH). No other conflicts of interest were reported.
The easy way to misread this
Do not interpret the lack of difference in startle response as evidence that children with ASD do not experience anxiety. The null finding indicates that this specific physiological probe is insensitive to anxiety in this population, not that anxiety is absent or mild.