Trial-to-Trial Variability in Electrodermal Activity to Odor in Autism.
Sarah M Haigh, Yaara Endevelt-Shapira, Marlene Behrmann
PMID 32860323WHAT IT FOUND
Adults with autism did not show greater trial-to-trial variability in skin conductance to odor and faces.
They showed less variability to fear odor, but the overall group difference was not significant.
Key findings
01The autism group did not show greater overall trial-to-trial variability in skin conductance; the overall group difference was not significant.
02In the fear odor condition, while faces were also presented, the autism group showed significantly less trial-to-trial variability than controls, while the neutral odor condition showed no significant difference.
03Average peak skin conductance to faces differed by group and odor: the autism group had similar responses to fear and neutral odors, while controls had a larger response to fear.
STILL TO COME
How it was doneWhat they found
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What it does not show
Only 17 adults with autism and 19 neurotypical controls were analysed after exclusions, so the sample is small. All participants were male, so the findings may not apply to females with autism. The overall group difference in trial-to-trial variability was not significant, and the group by odor interaction was not significant, even though the separate fear odor comparison reached significance. The Bayes Factor for the variability interaction suggested evidence against a difference, so the fear odor finding should be interpreted cautiously. Skin conductance measures relative change, so it is unclear whether the autism group already had higher baseline activity, which could make the stimulus-evoked response look smaller. The study was not designed to test whether groups detected the fear odor differently, and the odors were presented without telling participants. The small number of face presentations prevented testing interactions between odor and facial emotion.
Declared interests
The authors declared no conflict of interest. The publication types list U.S. and non-U.S. government research support.
The easy way to misread this
Do not read this as evidence that adults with autism have greater skin conductance variability to odor and faces overall. The overall group difference was not significant, and the significant result was less variability only in the fear odor condition.