Outcome from Complicated versus Uncomplicated Mild Traumatic Brain Injury

Objective. To compare acute outcome following complicated versus uncomplicated mild traumatic brain injury (MTBI) using neurocognitive and self-report measures. Method. Participants were 47 patients who presented to the emergency department of Tampere University Hospital, Finland. All completed MRI scanning, self-report measures, and neurocognitive testing at 3-4 weeks after injury. Participants were classified into the complicated MTBI or uncomplicated MTBI group based on the presence/absence of intracranial abnormality on day-of-injury CT scan or 3-4 week MRI scan. Results. There was a large statistically significant difference in time to return to work between groups. The patients with uncomplicated MTBIs had a median of 6.0 days (IQR = 0.75–14.75, range = 0–77) off work compared to a median of 36 days (IQR = 13.5–53, range = 3–315) for the complicated group. There were no significant differences between groups for any of the neurocognitive or self-report measures. There were no differences in the proportion of patients who (a) met criteria for ICD-10 postconcussional disorder or (b) had multiple low scores on the neurocognitive measures. Conclusion. Patients with complicated MTBIs took considerably longer to return to work. They did not perform more poorly on neurocognitive measures or report more symptoms, at 3-4 weeks after injury compared to patients with uncomplicated MTBIs.Hindaw

Neuropsychological Outcome and Diffusion Tensor Imaging in Complicated versus Uncomplicated Mild Traumatic Brain Injury

This study examined whether intracranial neuroimaging abnormalities in those with mild traumatic brain injury (MTBI) (i.e., “complicated” MTBIs) are associated with worse subacute outcomes as measured by cognitive testing, symptom ratings, and/or diffusion tensor imaging (DTI). We hypothesized that (i) as a group, participants with complicated MTBIs would report greater symptoms and have worse neurocognitive outcomes than those with uncomplicated MTBI, and (ii) as a group, participants with complicated MTBIs would show more Diffusion Tensor Imaging (DTI) abnormalities. Participants were 62 adults with MTBIs (31 complicated and 31 uncomplicated) who completed neurocognitive testing, symptom ratings, and DTI on a 3T MRI scanner approximately 6-8 weeks post injury. There were no statistically significant differences between groups on symptom ratings or on a broad range of neuropsychological tests. When comparing the groups using tract-based spatial statistics for DTI, no significant difference was found for axial diffusivity or mean diffusivity. However, several brain regions demonstrated increased radial diffusivity (purported to measure myelin integrity), and decreased fractional anisotropy in the complicated group compared with the uncomplicated group. Finally, when we extended the DTI analysis, using a multivariate atlas based approach, to 32 orthopedic trauma controls (TC), the findings did not reveal significantly more areas of abnormal DTI signal in the complicated vs. uncomplicated groups, although both MTBI groups had a greater number of areas with increased radial diffusivity compared with the trauma controls. This study illustrates that macrostructural neuroimaging changes following MTBI are associated with measurable changes in DTI signal. Of note, however, the division of MTBI into complicated and uncomplicated subtypes did not predict worse clinical outcome at 6-8 weeks post injury

Comparison of MMPI-2 and PAI validity indicators to detect \ud feigned depression and PTSD symptom reporting

The purpose of this study was to compare the clinical utility of PAI and MMPI-2 validity indicators to detect exaggeration of psychological symptoms. Participants were 49 (75.5% female) Australian university students who completed the MMPI-2 and PAI under one of three conditions: Control [i.e., honest responding (n = 20)], Feign Post Traumatic Stress Disorder [PTSD (n = 15)], or Feign Depression (n = 14). Participants instructed to feign depression or feign PTSD had significantly higher scores on the majority of MMPI-2 and PAI validity indicators compared to controls. The Meyers Validity Index, the Obvious-Subtle index, and the Response Bias Scale were the most accurate MMPI-2 validity indicators. Diagnostic-specific MMPI-2 validity indicators, such as the Infrequency-PSTD scales and Malingered Depression scale, were not effective at detecting participants instructed to feign those conditions. For the PAI, the most accurate validity indicator was the MAL index; however, detection rates using this validity indicator was modest at best. The MMPI-2 validity indicators were clearly superior to those on the PAI at identifying feigned versus honest responding in this sample

Utility of the neurobehavioral symptom inventory validity-10 index to detect symptom exaggeration

The Neurobehavioral Symptom Inventory (NSI) has been recommended by the interagency Traumatic Brain Injury (TBI) Outcome Workgroup as an outcome measure for TBI research. A new symptom exaggeration index-the NSI Validity-10-can be calculated from its items, but its utility has not been evaluated in a malingering simulation study. Data from a prior analogue study were reanalyzed to examine the NSI Validity-10 test properties. The data were from a sample of 85 Australian undergraduate students. A battery of measures was completed under 1 of 3 experimental conditions: control (i.e., honest responding, n = 24), feign postconcussional disorder (PCD; n = 29), and feign posttraumatic stress disorder (PTSD; n = 32). Participants who feigned PTSD or PCD had significantly higher scores on the NSI Validity-10 compared with controls. There were minimal differences between the 2 feigning groups. Using the combined data from the feigning groups and assuming a 35% symptom exaggeration base rate, the optimal NSI Validity-10 cutoff score was ≥10. This cutoff score identified "probable exaggeration" (sensitivity = .75, specificity = 1.0, positive predictive power = 1.0, negative predictive power = .88). Diagnostic efficiency statistics for 25% and 45% base rates were also generated. The cutoff score identified in this study is lower than previously reported. Its properties are promising, but its usage requires careful consideration

Malingering base rates and detection methods in Australia

Neuropsychology malingering base rates have not been widely investigated in Australia. Estimates in North America vary with as many as 4 in 10 people evaluated for personal injury or compensation cases suspected of exaggerating symptoms. Data on Australian neuropsychology symptom exaggeration base rates were estimated using a modified and expanded version of a survey previously designed for this purpose (Mittenberg, Patton, Canyock, & Condit, 2002). Figures were based on an estimated 1818 annual cases involved in personal injury, (n = 542), disability (n = 109), criminal (n = 108), or medical (n = 1059) matters. Symptom exaggeration base rates associated with referral type and diagnoses were variable. Specifically, 17% of criminal, 13% of personal injury, 13% of disability or workers compensation, and 4% of medical or psychiatric cases were reported to involve symptom exaggeration or probable symptom exaggeration. The highest rates of symptom exaggeration included cases referred for mild head injury (23%), pain or somatoform disorders (15%), moderate to severe head injury (15%), and fibromyalgia or chronic fatigue (15%). Overall, Australian symptom exaggeration base rates reported in this study were lower compared with base rates previously reported in North America

A known-groups evaluation of the Response Bias Scale in a neuropsychological setting

We evaluated the Minnesota Multiphasic Personality Inventory-Second Edition (MMPI-2) Response Bias Scale (RBS). Archival data from 83 individuals who were referred for neuropsychological assessment with no formal diagnosis (n = 10), following a known or suspected traumatic brain injury (n = 36), with a psychiatric diagnosis (n = 20), or with a history of both trauma and a psychiatric condition (n = 17) were retrieved. The criteria for malingered neurocognitive dysfunction (MNCD) were applied, and two groups of participants were formed: poor effort (n = 15) and genuine responders (n = 68). Consistent with previous studies, the difference in scores between groups was greatest for the RBS (d = 2.44), followed by two established MMPI-2 validity scales, F (d = 0.25) and K (d = 0.23), and strong significant correlations were found between RBS and F (rs = .48) and RBS and K (r = −.41). When MNCD group membership was predicted using logistic regression, the RBS failed to add incrementally to F. In a separate regression to predict group membership, K added significantly to the RBS. Receiver-operating curve analysis revealed a nonsignificant area under the curve statistic, and at the ideal cutoff in this sample of >12, specificity was moderate (.79), sensitivity was low (.47), and positive and negative predictive power values at a 13% base rate were .25 and .91, respectively. Although the results of this study require replication because of a number of limitations, this study has made an important first attempt to report RBS classification accuracy statistics for predicting poor effort at a range of base rates

Ecological Validity of the WMS-III Rarely Missed Index in Personal Injury Litigation

The purpose of this study was to evaluate the clinical utility of the Rarely Missed Index (RMI) to detect cognitive exaggeration in 78 non-litigant patients (i.e., Mixed Clinical group) and 158 personal injury litigants (i.e., 20 Suspected Exaggerators, 12 Borderline Exaggerators, 126 Genuine Responders). The false positive error rate of the RMI in the Genuine Responder and Mixed Clinical group ranged from 5.4% to 8.6%. Positive RMI scores were found 25% and 41.7% of the Suspected Exaggerator and Borderline Exaggerator groups respectively. The clinical utility of the RMI to identify Suspected Exaggerators versus individuals in the Genuine Responder and Mixed Clinical groups revealed low sensitivity (sensitivity = .25), very high specificity (range = .91 to .95), moderate positive predictive power (range = .50 to .71), and moderate to high negative predictive power (range = .68 to .83). These results do not support the use of the RMI as a reliable predictor of cognitive exaggeration

Methods of Detecting Malingering and Estimated Symptom Exaggeration Base Rates in Australia

Neuropsychology malingering base rates have not been widely investigated in Australia. Estimates in North America vary with as many as 4 in 10 people evaluated for personal injury or compensation cases suspected of exaggerating symptoms. Data on Australian neuropsychology symptom exaggeration base rates were estimated using a modified and expanded version of a survey previously designed for this purpose (Mittenberg, Patton, Canyock, & Condit, 2002). Figures were based on an estimated 1818 annual cases involved in personal injury, (n = 542), disability (n = 109), criminal (n = 108), or medical (n = 1059) matters. Symptom exaggeration base rates associated with referral type and diagnoses were variable. Specifically, 17% of criminal, 13% of personal injury, 13% of disability or workers compensation, and 4% of medical or psychiatric cases were reported to involve symptom exaggeration or probable symptom exaggeration. The highest rates of symptom exaggeration included cases referred for mild head injury (23%), pain or somatoform disorders (15%), moderate to severe head injury (15%), and fibromyalgia or chronic fatigue (15%). Overall, Australian symptom exaggeration base rates reported in this study were lower compared with base rates previously reported in North America