SA62. The Auditory Brainstem Response to Complex Sounds (cABR) Indexes Cognitive Network Function in Schizophrenia

Abstract

Abstract Background: The auditory brain stem response to complex sounds (cABR) is an event-related potential (ERP) biomarker that quantifies sound encoding in the brain stem and midbrain. Although it has not yet been thoroughly investigated in schizophrenia (SZ), the cABR has demonstrated sufficient sensitivity for predicting response to at least one form of auditory-targeted cognitive training. We therefore aimed to examine whether the efficiency and accuracy of auditory encoding would be associated with the perception of speech-in-noise (SIN) and other higher order cognitive abilities that are commonly impaired in SZ. Methods: Thirty-one SZ patients in a transitional care facility underwent electroencephalography (EEG) testing with the cABR paradigm which consisted of 40 msec /da/ speech stimulus, presented binaurally with a 50 msec interstimulus interval (ISI). cABR onset (Peak A) latency and stimulus-to-response cross-correlations were calculated as an index of speech encoding timing and accuracy. Participants also completed the MATRICS Consensus Cognitive Battery (MCCB) and a modified version of QuickSIN, a measure of speech-in-noise perception. Results: Faster cABR peak A latency (mean = 7.93, SD = 1.41 msec) was associated with better speech-in-noise discriminability (r = −.47), CPT-IP attention (r = −.40), working memory (r = −.54 to r = −.62), and global cognition (r = −.44). Stimulus-to-response cABR encoding was positively associated with verbal learning and memory performance (r = .38, P < .05); its relationship with speech-in-noise discriminability trended toward significance (r = .33, P = .07). Conclusion: The cABR provides important information about the accuracy and efficiency of sound encoding within the brain stem. Its amplitude and timing appear to reflect functioning of the neural networks underlying speech perception and other functionally significant cognitive domains in SZ. Ongoing studies will assess whether these and other cABR parameters can be used to predict and monitor response to procognitive interventions in SZ.