Faculty Bibliography

Individuals who sustain a concussion may continue to experience problems long after their injury. However, it has been postulated in the literature that the relationship between a concussive injury and persistent complaints attributed to it is mediated largely by the development of symptoms associated with posttraumatic stress disorder (PTSD) and depression. We sought to characterize cognitive deficits of adult patients who had persistent symptoms after a concussion and determine whether the original injury retains associations with these deficits after accounting for the developed symptoms that overlap with PTSD and depression. We compared the results of neurocognitive testing from 33 patients of both genders aged 18-55 at 3 months to 5 years post-injury with those from 140 control subjects. Statistical comparisons revealed that patients generally produced accurate responses on reaction time-based tests, but with reduced efficiency. On visual tracking, patients increased gaze position error variability following an attention demanding task, an effect that may reflect greater fatigability. When neurocognitive performance was examined in the context of demographic- and symptom-related variables, the original injury retained associations with reduced performance at a statistically significant level. For some patients, reduced cognitive efficiency and fatigability may represent key elements of interference when interacting with the environment, leading to varied paths of recovery after a concussion. Poor recovery may be better understood when these deficits are taken into consideration.

BACKGROUND: In the evaluation of neurorehabilitation patients involved in compensation or litigation, it is often assumed that poor performance or exaggerated symptoms reflects an intentional attempt to game the system. PURPOSE: The purpose of this article is to review multiple issues that can contribute to invalid symptom reporting and performance. CONCLUSIONS: Multiple factors relevant to normal behavior, including observations from social psychology and behavioral economics, are important in the context of invalid symptom reporting and performance. These factors, which include pre-injury traits and beliefs (e.g., beliefs about prognosis and symptoms after TBI), factors at the time of initial treatment (e.g., expectations of recovery, nocebo effects, stereotype threat), and thoughts and feelings during evaluations (e.g., anger, resentment, injustice), may be important explanations. To best serve our patients, further research is needed to illuminate these relative effects on performance compared to "not trying."

A minority of individuals will continue to experience debilitating symptoms for more than several months after sustaining a concussion. These problems may have multiple causes, including persistence of the original concussion symptoms, but they also may be due to factors such as depression and anxiety, physical problems, and psychological issues (including coping with an adverse insurance and legal system). This article reviews the differential diagnosis and treatment strategies for patients with chronic symptoms that persist after a concussion.