Considerations for the assessment of blast exposure in service members and veterans.

Introduction: Blast exposure is an increasingly present occupational hazard for military service members, particularly in modern warfare scenarios. The study of blast exposure in humans is limited by the lack of a consensus definition for blast exposure and considerable variability in measurement. Research has clearly demonstrated a robust and reliable effect of blast exposure on brain structure and function in the absence of other injury mechanisms. However, the exact mechanisms underlying these outcomes remain unclear. Despite clear contributions from preclinical studies, this knowledge has been slow to translate to clinical applications. The present manuscript empirically demonstrates the consequences of variability in measurement and definition across studies through a re-analysis of previously published data from the Chronic Effects of Neurotrauma Study 34. Methods: Definitions of blast exposure used in prior work were examined including Blast TBI, Primary Blast TBI, Pressure Severity, Distance, and Frequency of Exposure. Outcomes included both symptom report and cognitive testing. Results: Results demonstrate significant differences in outcomes based on the definition of blast exposure used. In some cases the same definition was strongly related to one type of outcome, but unrelated to another. Discussion: The implications of these results for the study of blast exposure are discussed and potential actions to address the major limitations in the field are recommended. These include the development of a consensus definition of blast exposure, further refinement of the assessment of blast exposure, continued work to identify relevant mechanisms leading to long-term negative outcomes in humans, and improved education efforts.

Validation of the personality assessment inventory (PAI) cognitive bias (CBS) and cognitive bias scale of scales (CB-SOS) in a post-deployment veteran sample.

Objective: The present study evaluated the function of four cognitive, symptom validity scales on the Personality Assessment Inventory (PAI), the Cognitive Bias Scale (CBS) and the Cognitive Bias Scale of Scales (CB-SOS) 1, 2, and 3 in a sample of Veterans who volunteered for a study of neurocognitive functioning. Method: 371 Veterans (88.1% male, 66.1% White) completed a battery including the Miller Forensic Assessment of Symptoms Test (M-FAST), the Word Memory Test (WMT), and the PAI. Independent samples t-tests compared mean differences on cognitive bias scales between valid and invalid groups on the M-FAST and WMT. Area under the curve (AUC), sensitivity, specificity, and hit rate across various scale point-estimates were used to evaluate classification accuracy of the CBS and CB-SOS scales. Results: Group differences were significant with moderate effect sizes for all cognitive bias scales between the WMT-classified groups (d = .52-.55), and large effect sizes between the M-FAST-classified groups (d = 1.27-1.45). AUC effect sizes were moderate across the WMT-classified groups (.650-.676) and large across M-FAST-classified groups (.816-.854). When specificity was set to .90, sensitivity was higher for M-FAST and the CBS performed the best (sensitivity = .42). Conclusion: The CBS and CB-SOS scales seem to better detect symptom invalidity than performance invalidity in Veterans using cutoff scores similar to those found in prior studies with non-Veterans.

Initial Validation of the Mid-Atlantic Mental Illness Research, Education, and Clinical Center Assessment of Traumatic Brain Injury.

With the increasing prevalence of traumatic brain injury (TBI), the need for reliable and valid methods to evaluate TBI has also increased. The purpose of this study was to establish the validity and reliability of a new comprehensive assessment of TBI, the Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MIRECC) Assessment of TBI (MMA-TBI). The participants in this study were post-deployment, combat exposed veterans. First, MMA-TBI outcomes were compared with those of independently conducted clinical TBI assessments. Next, MMA-TBI outcomes were compared with those of a different validated TBI measure (the Ohio State University TBI Identification method [OSU-TBI-ID]). Next, four TBI subject matter experts independently evaluated 64 potential TBI events based on both clinical judgment and Veterans Administration/Department of Defense (VA/DoD) Clinical Practice Guidelines. Results of the MMA-TBI algorithm (based on VA/DoD clinical guideline) were compared with those of the subject matter experts. Diagnostic correspondence with independently conducted expert clinical evaluation was 96% for lifetime TBI and 92% for deployment-acquired TBI. Consistency between the MMA-TBI and the OSU-TBI-ID was high (κ = 0.90; Kendall Tau = 0.94). Comparison of MMA-TBI algorithm results with those of subject matter experts was high (κ = 0.97-1.00). The MMA-TBI is the first TBI interview to be validated against an independently conducted clinical TBI assessment. Overall, results demonstrate the MMA-TBI is a highly valid and reliable instrument for determining TBI based on VA/DoD clinical guidelines. These results support the need for application of standardized TBI criteria across all diagnostic contexts.

Evaluating the motor slowing hypothesis of depression.

The purpose of this study was to evaluate the hypothesis that processing speed deficits are the primary cognitive deficits in those with depression, consistent with the motor slowing hypothesis. Participants (n=223) were research volunteers who served in the US military since September 11, 2001, and denied a history of significant brain injuries. Depression was measured using a structured interview, the Personality Assessment Inventory (PAI), and the Beck Depression Inventory-II (BDI-II). Outcomes included performance on 10 processing speed variables. Invalid performance/report accounted for significant variance for 8 of 10 processing speed measures. There was not a consistent pattern of slowed processing speed in those with current depressive diagnoses compared to those without. However, depression symptom burden per the PAI Depression scale was significant for 7 of 10 processing speed tests. Only non-dominant fine motor dexterity was significantly slower in those with high versus low burden using BDI-II quartiles. Thus, the motor slowing hypothesis was supported, but only for depression burden and not diagnostic status or high versus low categorical classification. These results underscore the importance of validity assessment and consideration of how one measures psychiatric constructs when evaluating relations among symptoms and cognition.