Error processing by individuals with specific language impairment: An ERP study

The purpose of the present study was to investigate error processing in individuals with Specific Language Impairment (SLI) using behavioral and electrophysiological measures. Error processing is an executive function that remains unexplored in individuals with SLI. Its crucial role in learning new skills and in improving performance promoted the evaluation of this skill in individuals whose learning abilities remain elusive. The first hypothesis of the present study was that the Error Related Negativity (ERN), a component of the Event Related Potentials (ERP) that is associated with error commission would be abnormal in children with SLI in comparison to their age and gender matched peers. It was further predicted that error correction abilities as measured by the proportion of corrected errors and by the slowing of responses following errors would be impaired in children with SLI. The second hypothesis was that children with SLI would over rely on the availability of external information indicating that an error had been made, and thus would exhibit an ERN to the feedback rather than to the response in a task where the feedback is useless for task performance.In the present study, 10 children ages 7--10 years with SLI and 10 age and gender matched control with normal language development performed two versions of the Eriksen's Flanker task while their EEG was recorded. The EEG was recorded using high-density 128-channel Ag/AgCl electrode nets from EGI. The children with normal language (NL) displayed a classic fronto-central ERN, while the SLI group exhibited no ERN to incorrect responses. Moreover, ERN to response was not detected in the SLI group, even for erroneous responses that were corrected. On average, the children in the NL group corrected more of their errors than did the children in the SLI group. The additional slowing of responses following errors was not found in either of the groups. In contrast to our predictions, ERN to the feedback, in a task in which the feedback was useless, was detected in the NL group but not in the SLI group. These results are interpreted as reflecting an immature error monitoring system in the NL group, and an impaired system in the SLI group, and are discussed within the information-processing framework.