Neuropsychological tests have limited sensitivity in identifying subtle residual cognitive impairments in patients with good medical recovery from head injury and post-concussive syndrome. Detecting and characterizing residual "real life" cognitive difficulties can be problematic for treatment purposes. This study investigated the usefulness of a well-standardized and validated cognitive simulation procedure that is based on complexity theory (The Strategic Management Simulation or SMS) for detecting such impairments. Twenty adults who had suffered moderate closed head injury (CHI) but now generated normal or close to normal neuropsychological test scores, yet continued to experience family, work, or other problems, were compared with matched controls. Comparisons of the patient and control group on simulation scores indicated no significant differences for single, well-structured task components or for information search activity. In contrast, the CHI sample was impaired on numerous tasks that require intermediate or complex cognitive efforts. The CHI sample generated significantly lower performance scores for strategic functioning, activity levels, information utilization, emergency responsiveness, planning, and breadth of decision-making. These findings suggest that SMS may provide a highly sensitive assessment tool for the assessment of subtle cognitive deficits after CHI. (Contains 2 tables.)