Patterns and reliability of EEG during error monitoring for internal versus external feedback in schizophrenia

Background: Accurately monitoring one's performance on daily life tasks, and integrating internal and external performance feedback are necessary for guiding productive behavior. Although internal feedback processing, as indexed by the error-related negativity (ERN), is consistently impaired in schizophrenia, initial findings suggest that external performance feedback processing, as indexed by the feedback negativity (FN), may actually be intact. The current study evaluated internal and external feedback processing task performance and test-retest reliability in schizophrenia. Methods: 92 schizophrenia outpatients and 63 healthy controls completed a flanker task (ERN) and a time estimation task (FN). Analyses examined the Delta ERN and Delta FN defined as difference waves between correct/positive versus error/negative feedback conditions. A temporal principal component analysis was conducted to distinguish the Delta ERN and Delta FN from overlapping neural responses. We also assessed test-retest reliability of Delta ERN and Delta FN in patients over a 4-week interval. Results: Patients showed reduced Delta ERN accompanied by intact Delta FN. In patients, test-retest reliability for both Delta ERN and Delta FN over a four-week period was fair to good. Conclusion: Individuals with schizophrenia show a pattern of impaired internal, but intact external, feedback processing. This pattern has implications for understanding the nature and neural correlates of impaired feedback processing in schizophrenia. Published by Elsevier B.V.