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OADES, R.D.,
ZERBIN, D., & EGGERS, C. (1993).
Stimulus-Vergleichsprozesse bei psychotischen Jugendlichen mit paranoiden
und nicht-paranoiden Symptomen: "Mismatch Negativity" deutet auf differenzierte
Beeinträchtigungen. We expand on our initial reports of reduced mismatch negativity, MMN, (1991a ) and negative difference, Nd, (1991b) in schizophrenia by looking at the different representation of these indices of automatic and controlled processing of information in subgroups manifesting paranoid or nonparanoid schizophrenia. Methods: Using a 3-tone auditory oddball (standard 0.8 kHz, deviant 2.0 kHz and 1.4 kHz as deviant in a passive and target in an active presentation), subtraction waveforms for the frequency-deviant MMN, for 1.4 kHz Nd (active - passive) and P300 in both waveforms were studied. Subjects were 22 patients with schizophrenia (mean age 18y) separated into paranoid and nonparanoid groups by a median split of the SANS-SAPS ratings; 11 age-matched OCD and 22 healthy controls were also studied. Results:
Conclusions: Difference waves reflecting perceptual deviance (MMN) and a difference of meaning (Nd) are differentially affected in schizophrenia (amplitude and latency differences respectively) and between subgroups of schizophrenia, with the nonparanoid group being the more impaired. See later results (MMN in schizophrenia) from 1995a, 1996, and 1997a, (Nd in schizophrenia) 1994, 1996 and on the expression of 'difference waveforms' in normal adults (1995b) and the normal development of MMN & Nd (1997b) |