Evidence of specificity of a visual P3 amplitude modulation deficit in schizophrenia.
BACKGROUND
In a previous study, we found a reduced amplitude modulation of the visual P3 component of the event-related potential (ERP) in schizophrenic patients compared with healthy controls during inhibition in the Attention Network Test (ANT). The objective of the present study was to replicate this finding and to explore whether this cortical processing deficit is specific to schizophrenia.


METHODS
Sixteen schizophrenic patients, sixteen depressive patients, and sixteen healthy controls matched for age, sex, and education were included. Participants were tested with the ANT, a test of selective attention that provides behavioral estimates for alerting, orienting, and inhibition. 32-Channel electroencephalogram was recorded and visual P3 amplitudes were topographically analyzed and compared between groups.


RESULTS
There were no significant behavioral between-group differences in terms of mean reaction time, accuracy, and ANT effects alerting, orienting, and inhibition. Absolute visual P3 amplitude was not reduced in schizophrenia or depression. P3 amplitude modulation was defined as P3 amplitude at Pz as a function of ANT flanker conditions. We found a parietal P3 amplitude modulation deficit in schizophrenic patients (-.015) that was absent in both healthy controls (-.705; p = .002) and depressive patients (-1.022; p = .001).


CONCLUSIONS
The results provide evidence that a deficit of visual P3 amplitude modulation distinguishes schizophrenia from healthy and disease controls and provides greater discriminative power than absolute visual P3 amplitude.
Neuhaus
Andres H
AH
Department of Psychiatry and Psychotherapy, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany. andres.neuhaus@charite.de
Trempler
Niklas R
NR
Hahn
Eric
E
Luborzewski
Alexander
A
Karl
Christine
C
Hahn
Constanze
C
Opgen-Rhein
Carolin
C
Urbanek
Carsten
C
Schaub
Rainer
R
Dettling
Michael
M
D000328:Adult; D001288:Attention; D016022:Case-Control Studies; D002540:Cerebral Cortex; D003463:Cues; D003863:Depression / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009949:Orientation; D011930:Reaction Time; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013037:Spatial Behavior