Abstract
Studies have indicated that individuals with Klinefelter's syndrome (KS) exhibit deficits in executive functions. However, little attention has been paid to investigate control mechanism of executive functions, i.e., error monitoring, in individuals with KS. Two event-related potential (ERP) components, i.e., error-related negativity (Ne/ERN) and error positivity (Pe), are the electrophysiological markers of error monitoring. This case report presents the findings of error monitoring from an adult with KS using the electrophysiological technique. This KS individual displayed small ERN and Pe amplitudes, suggesting that he may exhibit deficient error detection and reaction, a lack of conscious error recognition, and nonproficient adjustment after an error. The findings of this report should stimulate further study in error monitoring in individuals with KS.