Showing papers by "Grant L. Iverson published in 2010"

“Good Old Days” Bias Following Mild Traumatic Brain Injury

Abstract: A small percentage of people with a mild traumatic brain injury (MTBI) report persistent symptoms and problems many months or even years following injury. Preliminary research suggests that people who sustain an injury often underestimate past problems (i.e., "good old days" bias), which can impact their perceived level of current problems and recovery. The purpose of this study was to examine the influence of the good old bays bias on symptom reporting following MTBI. The MTBI sample consisted of 90 referrals to a concussion clinic (mean time from injury to evaluation = 2.1 months, SD = 1.5, range = 0.8-8.1). All were considered temporarily fully disabled from an MTBI and they were receiving financial compensation through the Worker's Compensation system. Patients provided post-injury and pre-injury retrospective ratings on the 16-item British Columbia Post-concussion Symptom Inventory (BC-PSI). Ratings were compared to 177 healthy controls recruited from the community and a local university. Consistent with the good old bays bias, MTBI patients retrospectively endorsed the presence of fewer pre-injury symptoms compared to the control group. Individuals who failed effort testing tended to retrospectively report fewer symptoms pre-injury compared to those patients who passed effort testing. Many MTBI patients report their pre-injury functioning as better than the average person. This can negatively impact their perception of current problems, recovery from injury, and return to work.

Interview versus questionnaire symptom reporting in people with the postconcussion syndrome.

Abstract: OBJECTIVE To compare spontaneous, interview-based, postconcussion symptom reporting to endorsement of symptoms on a standardized questionnaire. PARTICIPANTS Sixty-one patients referred to a concussion clinic following mild traumatic brain injury. PROCEDURE Patients recalled their current symptoms and problems via open-ended interview and then completed a structured postconcussion checklist. MAIN OUTCOME MEASURES Open-ended interview and the British Columbia Postconcussion Symptom Inventory (BC-PSI). RESULTS On average, patients endorsed 3.3 symptoms (SD = 1.9) during open-ended interview and 9.1 symptoms (SD = 3.2) on the BC-PSI (P < .001). Approximately 44% endorsed 4 or more symptoms during interview compared with 92% on the BC-PSI. The percentage of patients endorsing items on the BC-PSI compared with interview was significantly greater on all 13 items. It was common for patients to endorse symptoms as moderate-severe on the BC-PSI, despite not spontaneously reporting those symptoms during the interview. CONCLUSIONS Clinicians need to be cautious when interpreting questionnaires and be aware of the possibility of nonspecific symptom endorsement, symptom overendorsement, symptom expectations influencing symptom endorsement, and the nocebo effect.

Influence of poor effort on self-reported symptoms and neurocognitive test performance following mild traumatic brain injury.

Abstract: When considering a diagnosis of postconcussion syndrome, clinicians must systematically evaluate and eliminate the possible contribution of many differential diagnoses, comorbidities, and factors that may cause or maintain self-reported symptoms long after mild traumatic brain injury (MTBI). One potentially significant contributing factor is symptom exaggeration. The purpose of the study is to examine the influence of poor effort on self-reported symptoms (postconcussion symptoms and cognitive complaints) and neurocognitive test performance following MTBI. The MTBI sample consisted of 63 referrals to a concussion clinic, evaluated within 5 months post injury (M = 2.0, SD = 1.0, range = 0.6-4.6), who were receiving financial compensation from the Workers' Compensation Board. Participants completed the Post-Concussion Scale (PCS), British Columbia Cognitive Complaints Inventory (BC-CCI), selected tests from the Neuropsychological Assessment Battery Screening Module (S-NAB), and the Test of Memory Malingering (TOMM). Participants were divided into two groups based on TOMM performance (15 fail, 48 pass). There were significant main effects and large effect sizes for the PCS (p = .002, d = 0.79) and BC-CCI (p = .011, d = 0.98) total scores. Patients in the TOMM fail group scored higher than those in the TOMM pass group on both measures. Similarly, there were significant main effects and/or large effect sizes on the S-NAB. Patients in the TOMM fail group performed more poorly on the Attention (p = .004, d = 1.26), Memory (p = .006, d = 1.16), and Executive Functioning (p > .05, d = 0.70) indexes. These results highlight the importance of considering the influence of poor effort, in conjunction with a growing list of factors that can influence, maintain, and/or mimic the persistent postconcussion syndrome.

Identifying cognitive problems in children and adolescents with depression using computerized neuropsychological testing.

Abstract: Depression in children and adolescents can negatively impact cognitive functioning, social development, and academic performance. The purpose of this study was to determine whether a computerized battery of neuropsychological tests could detect neurocognitive difficulties in children and adolescents with depression. Participants included 30 children and adolescents between the ages of 9 and 17 years (M = 14.6, SD = 2.1) with a clinical diagnosis of depression. Healthy control participants were individually matched on age, education, sex, race, primary language, handedness, and self-reported computer familiarity. All participants completed the Central Nervous System Vital Signs computerized battery. This battery of seven tests yields 23 test scores and 5 domain scores (Memory, Psychomotor Speed, Reaction Time, Complex Attention, and Cognitive Flexibility). Children and adolescents with depression performed worse on the Memory (Cohen's d = .43) and Complex Attention domains (d = .58) than matched controls. On the individual test scores, children and adolescents with depression performed worse on delayed verbal memory (d = .63), delayed visual memory (d = .34), measures of reaction time (d = .34-.53), and accuracy/inhibition on complex attention tasks (d = .49-.65). When considering the five domain scores simultaneously, children and adolescents with depression were more likely to have two or more scores at or below the 5th percentile (p = .05). Children and adolescents with depression have problems with reduced processing speed, memory for verbal information, and executive functioning on this computerized battery of tests, which represents a feasible method for neuropsychological screening.

Mild traumatic brain injury meta-analyses can obscure individual differences.

Abstract: Primary objective: Several published meta-analyses indicate that mild traumatic brain injury (MTBI) is associated with a favourable course of recovery over a period of days-to-weeks, with no indication of permanent impairment on neuropsychological testing by 3 months post-injury in group studies. These meta-analyses provide important but not definitive information relating to outcome from MTBI in individual patients. The purpose of this paper was to illustrate that a sub-group of patients with residual cognitive deficits could exist, yet be obscured using group inferential statistics.Main outcome and results: A sample of 30 concussed amateur athletes and a hypothetical sample of 30 adults who had sustained MTBIs were used to illustrate these statistical issues. In both groups, a minority of subjects with residual cognitive deficits were not identified using group statistics.Conclusions: It is important to appreciate that MTBI meta-analyses represent an aggregation of effect sizes derived from multiple gro...

A model to approaching and providing feedback to patients regarding invalid test performance in clinical neuropsychological evaluations.

Abstract: The use of symptom validity assessment has become commonplace in clinical neuropsychological evaluations. However, clinicians often struggle with how to provide patients with feedback regarding invalid responding or effort, because of the sensitive nature of the information that must be conveyed. A conceptual framework for providing such feedback is outlined in clinical neuropsychological evaluations, and recommendations for how to handle complaints are offered. Our feedback model is not meant to apply to individuals referred by attorneys or other non-clinical third parties (e.g., independent medical examination companies).

Clinical and methodological challenges with assessing mild traumatic brain injury in the military.

Abstract: BACKGROUND: A vast majority of traumatic brain injuries sustained by military personnel are mild in severity. In 2008, the United States Department of Defense officially mandated a screening program designed to identify deployment-related mild traumatic brain injuries and associated residual symptoms. OBJECTIVE: This article reviews this screening program, illustrates the clinical and methodological challenges associated with screening, and makes recommendations for improving the process of screening for mild traumatic brain injuries and related symptoms. Language: en

Effect of blood alcohol level on Glasgow Coma Scale scores following traumatic brain injury.

Abstract: Objective: It is a common clinical perception that alcohol intoxication systematically lowers Glasgow Coma Scale (GCS) scores when evaluating traumatic brain injury (TBI) However, the research findings in this area do not uniformly support this notion The purpose of this study is to examine the effects of blood alcohol level (BAL) on GCS scores following TBIMethod: Participants were 475 patients (64% male) who presented to a Level 1 trauma centre following a TBI Patients were selected if they were injured in a motor vehicle accident and had an available day-of-injury GCS, BAL and Computed Tomography (CT) brain scanResults: Overall, acute alcohol intoxication did not significantly affect GCS scores, even in patients with BALs of 200 mg dl−1 or higher When controlling for the effects of injury severity, acute alcohol intoxication affected GCS scores only in those patients with BALs greater than 200 mg dl−1 who also had intracranial abnormalities detected on CT scanConclusions: These findings suggest

Differential Effects of Alcohol Intoxication on S100B Levels Following Traumatic Brain Injury

Abstract: BACKGROUND:: In an acute care setting, evaluation of traumatic brain injury (TBI) is often complicated by alcohol intoxication. The purpose of this study is to evaluate the clinical utility of the protein S100B as a biochemical marker for identifying brain injury in patients who are intoxicated at the time of injury. METHODS:: The study participants were 160 patients who presented to a large urban Level I Trauma Centre in Vancouver, Canada. Patients were classified into four clinical groups (medical controls, trauma controls, mild TBI, and definite TBI) and two day-of-injury alcohol intoxication groups (i.e., sober and intoxicated). Blood samples were collected via venipuncture in heparinized tubes within 8 hours of injury. Measures of S100B concentration were obtained using a commercially available assay kit (Sangtec 100 Elisa). RESULTS:: For those patients who were sober at the time of injury, higher S100B levels were associated with TBI when compared with other physical injuries and general medical complaints. However, for patients who were intoxicated at the time of injury, there were uniformly low S100B levels across all clinical groups. CONCLUSIONS:: Although there seems to be a strong association between S100B levels and TBI, further research is required to establish the clinical role of S100B in patients with suspected TBI, particularly in patients whose clinical presentation is complicated by alcohol intoxication. Language: en

Identifying Cognitive Impairment in Adults with Mood Disorders Using Computerized Testing

Abstract: Objective: To develop and evaluate psychometric criteria for identifying cognitive impairment in adults with mood disorders. Participants & Methods: Participants were adults between the ages of 20 and 54, including 659 healthy control subjects, 84 unmedicated outpatients diagnosed with depression, 59 outpatients diagnosed with depression who were on medications at the time of the evaluation, and 43 outpatients with bipolar disorder. All completed the CNS Vital Signs computerized battery. This battery of seven tests yields five domain scores (Memory, Psychomotor Speed, Reaction Time, Complex Attention, and Cognitive Flexibility). Results: Base rates of low domain scores were calculated, using different cut-offs, for the healthy control subjects and the patients with mood disorders. Having two scores at or below the 5 th percentile occurred in 31.2% of the patients and only 8.2% of the control subjects [χ 2 (1)=66.67, p<.0001; Odds Ratio=5.1, 95% CI=3.4–7.7]. This low false positive rate was maintained across age groups, sexes, and education levels. African Americans (N=49) had higher false positive rates (i.e., 14.3%) than Caucasians (N=570; 7.0%). A larger proportion of patients with bipolar disorder (41.9%) than patients with depression (27.1-28.6%) met criteria for cognitive impairment. Conclusion: A substantial minority of adults with mood disorders appear to have cognitive impairment. The psychometric criterion for cognitive impairment on this computerized test battery has a low false positive rate.