AUDITORY SHORT-TERM-MEMORY IN SCHIZOPHRENIA - AN EVENT-RELATED BRAIN POTENTIALS STUDY

This study evaluated the early stages of sensory processing in patient s with schizophrenia using the mismatch negativity (MMN), an event-rel ated 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 wit h rare deviant repetitions in the alternating pattern. Deviant stimuli elicited an MMN at 120- to 180-msec latencies. The MMNs elicited by t he pitch deviations were reduced in amplitude in schizophrenics. No gr oup differences, however, were found in the MMN amplitude to pattern-d eviant stimuli. The results suggest reduced specificity in the neurona l response to physically deviant stimuli.