Click-evoked auditory brainstem responses & autism spectrum disorder: A meta-analytic investigation of disorder specificity

BACKGROUND: Click-evoked auditory brainstem response (ABR) alterations are associated with autism spectrum disorder (ASD), but the specificity of these findings to the disorder are unclear. We therefore performed a meta-analysis on ABRs and attention deficit/hyperactivity disorder (ADHD), a neurodevelopmental disorder that shares some etiologic and symptom overlap with ASD. METHOD: Seven papers compared ABR latency components (I, III, V, I–III, III–V, I–V) between participants with and without ADHD. We used random-effects regression to generate component-specific estimates (Hedges’ g) that adjusted for study sample sizes and the number of studies contributing to each estimate. We compared these estimates to our recently published meta-analysis of ABRs and ASD. RESULTS: All ADHD studies employed cross-sectional designs. ADHD was associated with longer latencies for Waves III and V (g=0.6, 95%CI 0.3,1.0 and g=0.6, 95%CI 0.2,0.9) and Waves I–III and I–V (g=0.7, 95%CI 0.2, 1.3 and g=0.6, 95%CI 0.3, 1.0). Effect sizes from the ASD and ADHD meta-analyses did not differ from each other. CONCLUSION: Similar patterns of ABR alterations are observed in ADHD and ASD. However, studies rarely screen for middle ear dysfunction or hearing loss and rely upon cross-sectional designs. Addressing these issues will inform the viability of ABRs as a prognostic and/or etiologic biomarker for these disorders.