Impairment in error monitoring predicts poor executive function in schizophrenia patients.
BACKGROUND
Impaired ability to detect and correct errors may contribute to poor cognitive and social function in schizophrenia.


OBJECTIVE
To test the hypothesis that impairment in error monitoring contributes to impaired executive function in schizophrenia.


METHODS
56 schizophrenia patients and 77 healthy individuals were tested with the Penn Conditional Exclusion test (PCET), a computerised test of executive function which allowed collection of accuracy and latency performance parameters. Error monitoring was assessed by analyzing reaction times for correct (RTC) and incorrect (RTI) responses. Tests of face recognition, working memory (WM) and processing speed were also administered.


RESULTS
Executive error-monitoring effort (EXER), calculated by dividing the difference between RTI and RTC by the sum of RTC and RTI, was significantly smaller in patients than controls. A regression model with the executive function (PCET total errors) as dependent variable showed independent contributions of EXER, verbal WM and spatial WM to test performance and explained 35% of the variance. EXER showed significant association with error-monitoring effort for face recognition in patients but not controls.


CONCLUSIONS
Impaired error-monitoring contributes to poor executive function in schizophrenia. Independent contributions of error-monitoring effort and verbal WM to executive functions may reflect distinct contributions of prefrontal and medial frontal cortical dysfunctions. Error-monitoring mechanisms in different cognitive domains may share more neural resources in schizophrenia than in healthy individuals, reflecting inefficient processing.
Silver
Henry
H
Brain Behavior Laboratory, Sha'ar Menashe Mental Health Center, Mobile Post Hefer, Israel. mdsilver@tx.technion.ac.il
Goodman
Craig
C
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001569:Benzodiazepines / Q000627:therapeutic use; D002908:Chronic Disease; D003024:Clozapine / Q000627:therapeutic use; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D009483:Neuropsychological Tests; D000077152:Olanzapine; D010879:Piperazines / Q000627:therapeutic use; D011930:Reaction Time; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D020377:Self Efficacy; D012720:Severity of Illness Index; D013844:Thiazoles / Q000627:therapeutic use
D014150:Antipsychotic Agents; D010879:Piperazines; D013844:Thiazoles; D001569:Benzodiazepines; C092292:ziprasidone; D003024:Clozapine; D018967:Risperidone; D000077152:Olanzapine