Poster #: 15
Topic: Clinical applications (incl. consciousness)
Friday, Sep 11, 2015
Mismatch negativity indexes central auditory system dysfunction and early adaptive plasticity in schizophrenia
1VA San Diego Healthcare System, San Diego, CA, USA
2Department of Psychiatry, University of California-San Diego, USA
Mismatch negativity (MMN) deficits in schizophrenia (Sz) are robust, reliable, and associated with cognitive and psychosocial impairments. Although it is essential for effective communication, the ability to perceive speech in background noise has not yet been evaluated in neuropsychiatric populations with characteristic central auditory processing deficits, like SZ. We examined the relationship between MMN and speech-in-noise (SIN) perception in the context of an ongoing randomized trial of auditory training (AT). Participants were 11 Sz patients in a transitional care facility. The MMN paradigm utilized a 1000 Hz, 50-msec standard tone (84%), and four 50-msec frequency-modulated tone “sweeps,” with frequency ranges varying from 500 to 1500 Hz (16%), corresponding to the parameters of the AT stimuli. SIN perception was measured with QuickSIN, and clinical symptoms were assessed with the Scales for the Assessment of Positive/Negative Symptoms (SAPS/SANS). All measures, including MMN, were administered at baseline, followed by one hour of AT or non-auditory computer games (CG). MMN was re-assessed after the hour of AT or CG. Pre-training MMN amplitude was significantly associated with SIN perception and negative symptoms. Change in MMN amplitude after one hour was associated with negative symptoms in the AT group, but not the CG group. There was no relationship between positive symptoms and baseline MMN or MMN change. MMN appears to provide a neural index of SZ patients’ ability to extract relevant acoustic cues from noisy auditory environments, which negatively impacts social behavior. MMN also demonstrates early sensitivity to experience-dependent adaptive plasticity within the central auditory system.