?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Auditory+event-related+potential+(ERP)+and+difference-wave+topography+in+schizophrenic+patients+with%2Fwithout+active+hallucinations+and+deluisions%3A+a+comparison+with+young+obsessive-compulsive+disorder+(OCD)+and+healthy+subjects&rft.creator=OADES%2C+Robert+D.&rft.creator=ZERBIN%2C+D.&rft.creator=DITTMANN-BALCAR%2C+A.&rft.creator=EGGERS%2C+C.&rft.subject=Neurophysiology&rft.subject=Neuropsychiatry&rft.subject=Perceptual+Cognitive+Psychology&rft.description=Introduction%3A+%0AEvent-related+potentials+(ERPs)+in+schizophrenics+have+been+reported+to+show+a+reduced+P3+on+the+left+and+less+frontal+mismatch+negativity.+But+the+specificity+of+such+findings+to+component%2C+its+locus%2C+the+type+of+eliciting+event+and+patient+group+remains+uncertain.+Hence%2C+we+examined+ERP+topography+for+P3%2C+N2+and+3+precursor+peaks+according+to+stimulus+(3-tone+oddball)%2C+attention+condition+(diffuse%2Ffocused)+and+four+types+of+difference-waves+(Mismatch+negativity%2C+Processing+negativity%2C+Negative+difference+(Nd)+and+the+'Goodin-Waveform').+%0A%0AMethod%3A+%0AWe+contrasted+ERPs+in+a+3-tone+oddball+task-form+in+24+healthy+(mean+18.5y+of+age)+and+13+OCD+(mean+age+16.3+y)+subjects+with+schizophrenic+patients+with+high+versus+low+ratings+of+active+delusions+and+hallucinations+(12+paranoid-hallucinatory%2C+PH+%5Bmean+age+18.5y%5D%3B+12+nonparanoid%2C+NP+%5Bmean+age+18.9y%5D)+%0A%0AResults%3A+%0A1.+P3+peaks+were+delayed+and+reduced+in+NP+and+PH+groups.+Peaks+in+the+midline+were+usual+in+the+focused+attention+condition%2C+but+a+right+bias+in+diffuse+attention+(passive+presentation).+%0A2.+P3+responses+to+irrelevant+non-targets+remained+lateralised+in+NP%2C+and+small+in+OCD+patients.+All+showed+a+small+left+and+anterior+bias+in+the+P3-like+peak+recorded+after+subtraction+in+the+difference+waves.+%0A3.+Mismatch+negativity+(MMN)+peaks+shifted+to+the+right+in+OCD%2C+laterally+to+both+sides+in+PH+and+more+posteriorly+in+NP+patients.+%0A4.+Frontal+processing+negativity+was+biased+to+the+left+(early)+in+NP+and+to+the+right+(late)+in+PH+groups.+%0A5.+Early+peak+topography+in+the+difference+waveforms+reflected+some+of+these+later+changes+(e.g.%2C+for+PH+and+NP+groups+the+normal+right+bias+in+the+P1-like+peak+was+absent%3B+the+N1-like+peak+was+reduced+and+widely+distributed%3A+for+the+NP+group%2C+the+P2-like+peak+appeared+smaller+on+the+left).+%0A6.+In+OCD+patients%2C+the+peak+latencies+were+topographically+undifferentiated+for+P1+and+P2%2C+or+delayed+in+the+case+of+the+N2+component.+%0A%0AConclusions%3A+%0AA)+The+OCD+group+showed+an+unusual+regional+allocation+of+processing+effort.+%0AB)+Before+200+ms%2C+fronto-central+activity+was+more+widespread+in+both+the+PH+and+NP+groups.+%0AC)+NP+patients%2C+in+particular%2C+treated+irrelevant+stimuli+anomalously.+%0AD)+Lateralisation+of+negativity+in+target-+and+nontarget-derived+difference+waves+may+reflect+differential+disruption+of+the+frontal-temporal+dialogue+in+registering+important+vs.+unimportant+features.+Indeed%2C+the+apparent+left%2Fright+differences+of+negative+difference+(Nd)+or+processing+negativity+amplitude+may+not+so+much+reflect+amplitude+differences+as+a+delayed+latency+over+left+frontal+areas+in+PH+and+over+the+right+frontal+areas+in+NP+patients+with+schizophrenia.+%0A&rft.publisher=Elsevier&rft.date=1996&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Fcogprints.org%2F1167%2F2%2FInt.J.Psychophysiology.pdf&rft.identifier=++OADES%2C+Robert+D.+and+ZERBIN%2C+D.+and+DITTMANN-BALCAR%2C+A.+and+EGGERS%2C+C.++(1996)+Auditory+event-related+potential+(ERP)+and+difference-wave+topography+in+schizophrenic+patients+with%2Fwithout+active+hallucinations+and+deluisions%3A+a+comparison+with+young+obsessive-compulsive+disorder+(OCD)+and+healthy+subjects.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F1167%2F