How specific are deficits in mismatch negativity generation to schizophrenia?
BACKGROUND
Mismatch negativity (MMN) is an auditory event-related potential that provides an index of auditory sensory memory. Deficits in MMN generation have been repeatedly demonstrated in chronic schizophrenia. Their specificity to schizophrenia has not been established.


METHODS
Mismatch negativity to both duration and frequency deviants was investigated in gender- and age-matched patients with schizophrenia or schizoaffective disorder (n = 26), bipolar disorder (n = 16), or major depression (n = 22) and healthy control subjects (n = 25).


RESULTS
Only patients with schizophrenia demonstrated significantly smaller mean MMN than did healthy control subjects. Detailed analyses showed significantly smaller MMN to both duration and frequency deviants in patients with schizophrenia than in healthy control subjects; however, the reduction of frequency MMN in patients with schizophrenia was not significant in the comparison across all groups. Mismatch negativity topography did not differ among groups. No consistent correlations with clinical, psychopathologic, or treatment variables were observed.


CONCLUSIONS
Mismatch negativity deficits, and by extension deficits in early cortical auditory information processing, appear to be specific to schizophrenia. Animal and human studies implicate dysfunctional N-methyl-D-aspartate receptor functioning in MMN deficits. Thus MMN deficits may become a useful endophenotype to investigate the genetic underpinnings of schizophrenia, particularly with regard to the N-methyl-D-aspartate receptor.
Umbricht
Daniel
D
Department of Psychiatric Research, University of Zurich, Zurich, Switzerland.
Koller
René
R
Schmid
Liselotte
L
Skrabo
Anja
A
Grübel
Claudia
C
Huber
Theo
T
Stassen
Hans
H
D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000503:physiopathology*; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory; D005260:Female; D007839:Functional Laterality; D006309:Hearing; D006801:Humans; D007360:Intelligence; D008297:Male; D008568:Memory; D008875:Middle Aged; D012559:Schizophrenia / Q000503:physiopathology*