Impaired non-verbal auditory memory maintenance in schizophrenia: An ERP study

Individuals with schizophrenia (SZ) exhibit deficits in speech perception in noise, which are closely related to their abnormalities in auditory working memory (WM). Auditory WM, especially the non-verbal auditory WM, serves as a bridge between perception, action, and long-term memory, playing a crucial role in integrating sound sequences to facilitate auditory object perception and auditory scene analysis (ASA). Although considerable research has been conducted on auditory sensory memory and visual WM in schizophrenia, studies specifically addressing non-verbal auditory WM remain scarce. Therefore, this study recorded the behavioral performance and event related potentials of 36 SZ and 36 healthy controls (HC) during a modified non-musical tone-sequence delayed matching-to-sample task (DMTS). The results showed that, in the tone-sequence DMTS, SZ had not only lower accuracy but also slower reaction times compared to the HC. More importantly, during the retention period, the memory maintenance of SZ begins to decay rapidly from the mid-stage, manifested by a significantly reduction in the late sustained anterior negativity (SAN2). Meanwhile, the early sustained anterior negativity (SAN1) in patients showed a significant correlation with their general pathological symptoms. The pathological symptoms can be predicted by the SAN1 under load 4 condition. This study provides empirical evidence for the impairment of non-verbal auditory WM maintenance in schizophrenia, which is of significant importance for understanding the auditory dysfunction and ASA difficulties experienced by SZ.