SU62. The 40-Hz Auditory Steady-State Response: A Sensitive and Predictive Biomarker of Perceptual Learning During Cognitive Training

Abstract

Background: Disturbances of auditory perception are characteristic features of schizophrenia (SZ) and contribute to cognitive and functional disability. Targeted Cognitive Training (TCT) of the auditory system has shown great promise for remediating cognitive impairments in SZ, but training‐associated gains vary across individuals and are diffcult to predict in the early stages of treatment. The Auditory Steady State Response (ASSR) to gamma‐frequency stimulation is increasingly used as a functional biomarker of central auditory system plasticity in translational neuroscience. Here, we aimed to determine whether gamma evoked power and phase synchronization measures are sensitive to and predict the amount of perceptual learning that occurs during initial exposure to TCT. Methods: Participants were 29 SZ patients in a residential transitional care facility randomized to either auditory TCT (n = 18) or nonauditory computer games (n = 11). ASSR was assessed twice: immediately before and after 1 hour of auditory TCT or nonauditory CG. The auditory cognitive exercises in TCT require participants to make increasingly diffcult frequency discrimination time‐order judgments. The ASSR paradigm utilized 1‐msec, 85‐dB clicks presented in 500‐ms trains at a frequency of 40 Hz. Results: Signifcant increases in gamma evoked power were detected in the TCT (t(17) = 2.19, P =.04), but not CG group (t(10) =.41, P =.69). A trend toward increased gamma phase locking was also detected in the TCT group in the 100‐200 ms poststimulus‐onset window (P =.06). Baseline gamma evoked power (r = 0.52) and phase locking (r = 0.45) were both positively correlated with perceptual learning within auditory training session (P