Objective: Naturalistic and neurophysiological assessments are relevant as outcome measures in autism intervention trials because they provide, respectively, ecologically valid information about functioning and underlying neurocognitive mechanisms. We conducted a systematic review to highlight which specific neurophysiological techniques, experimental tasks, and naturalistic protocols have been used to assess neural and behavioral functioning in autism intervention studies.
Methods: Studies were collected from four electronic databases between October 2019 and February 2020: MEDLINE (via PubMed), PsycINFO, LILACS, and Web of Science, and were included if they used structured observational, naturalistic, or neurophysiological measures to assess the efficacy of a nonpharmacological intervention for ASD.
Results: Fourteen different measures were used by 64 studies, with the Autism Diagnostic Observation Schedule the most frequently used instrument. Thirty-seven different coding systems of naturalistic measures were used across 51 studies, most of which used different protocols. Twentyfour neurophysiological measures were used in 16 studies, with different experimental paradigms and neurophysiological components used across studies.
Conclusions: Cross-study variability in assessing the outcomes of autism interventions may obscure comparisons and conclusions about how different behavioral interventions affect autistic social communication and underlying neurophysiological mechanisms.
Keywords: Autism; intervention; naturalistic assessments; neurophysiology; outcome measures.