Temporal dissociation of components of cognitive control dysfunction in severe TBI: ERPs and the cued-Stroop task.

Cognitive control comprises two essential interactive component processes: a regulative component supporting the activation and implementation of control and an evaluative component that monitors the need for regulative control and signals when adjustments in control are necessary. Survivors of severe traumatic brain injury (TBI) experience cognitive control impairments, but the specific nature of these impairments is poorly characterized. Using event-related potentials (ERPs) acquired in the context of a trial-by-trial task-switching version of the Stroop task we temporally dissociated the regulative and evaluative processes in order to shed light on the potential roles of these components in TBI-related cognitive control impairment. Behaviorally, TBI patients showed a specific performance deficit suggestive of a failure to implement cognitive control in the service of processing conflict information. ERP findings showed that TBI patients were impaired in both the implementation of control and subsequent detection and processing of conflict. TBI patients were also impaired on a measure of working memory capacity, a measure that correlated with the ability to implement regulative control and overcome conflict. These findings suggest that patients with predominantly chronic severe TBI patients are impaired on both regulative and evaluative components of cognitive control, and may have implications for the design and evaluation of behavioral and pharmacological remediation strategies.