Auditory short-term memory in schizophrenia: An event-related brain potentials study

This study evaluated the early stages of sensory processing in patients with schizophrenia using the mismatch negativity (MMN), an event-related brain potential associated with auditory memory. Twelve patients with schizophrenia and 12 age-matched controls were presented with: (1) sequences of identical tones that included occasional deviant tones differing in pitch and (2) sequences of tones alternating in pitch with rare deviant repetitions in the alternating pattern. Deviant stimuli elicited an MMN at 120- to 180-msec latencies. The MMNs elicited by the pitch deviations were reduced in amplitude in schizophrenics. No group differences, however, were found in the MMN amplitude to pattern-deviant stimuli. The results suggest reduced specificity in the neuronal response to physically deviant stimuli.