Minimal Differences in Auditory and Visual Oddball Tasks in Autism: A Systematic Review and Meta-Analysis

Autism is a neurodevelopmental condition that presents with significant changes in sensory processing, and which has recently been associated with differences in sensory expectations. One method for measuring sensory expectations (i.e., predictions) is via oddball paradigms, in which a deviant stimulus is presented following a series of repeated stimuli. In EEG signals, this deviance elicits a characteristic mismatch negativity (MMN) response, which acts as a neural signature of deviance detection and perception. Given the growing focus on sensory prediction in autism, a number of studies have now employed the oddball paradigm, with mixed results. We conducted a meta-analysis to better understand the utility of oddball paradigms in evaluating sensory prediction differences in the autism population. A comprehensive literature search queried the PubMed database for empirical auditory and visual oddball studies comparing autistic and non-autistic individuals. Statistical analyses were all conducted in R. We estimated true effect sizes and characterized the effects of various study characteristics on effect size using a multi-level random effects model and robust variance estimation (RVE). Publication bias and study quality were also assessed. Although individual studies have reported differences, the results of this meta-analysis suggest no significant group differences between autistic and non-autistic individuals in auditory or visual oddball perception, recognition, or neural signatures. When used in autism research, auditory and visual oddball MMN responses may not inherently capture changes in sensory prediction, and significant findings may be related more to individual variability than diagnostic group.