Validation of Military Occupational Specialty as a Proxy for Blast Exposure Using the Salisbury Blast Interview

Abstract Evaluating large data sets precludes the ability to directly measure individual experiences, instead relying on proxies to infer certain constructs. Blast exposure is a construct of study currently in its infancy, resulting in diverse definitions and measurements across studies. The purpose of the present study was to validate military occupational specialty (MOS) as a proxy for blast exposure in combat veterans. A total of 256 veterans (86.33% male) completed the Salisbury Blast Interview (SBI) and Mid-Atlantic Mental Illness Research Education and Clinical Center (MIRECC) Assessment of Traumatic Brain Injury (MMA-TBI). MOS was collected through record review and categorized into low and high risk for blast exposure. Chi-square analyses and t tests compared SBI metrics between MOS categories. Receiver operating characteristic (ROC) analyses evaluated the diagnostic accuracy of MOS category in determining blast exposure severity. Veterans in high-risk MOS were more likely to have experienced blast and deployment TBI (ps < 0.001) than were those in low-risk MOS. ROC analyses indicated good specificity (81.29-88.00) for blast and deployment TBI outcomes, suggesting that low-risk MOS is generally associated with an absence of blast and deployment TBI outcomes. Sensitivity was low (36.46-51.14), indicating that MOS risk level was not a good predictor of the presence of these outcomes. Results demonstrate that high-risk MOSs will identify individuals with blast exposure and deployment TBI history whereas low-risk MOSs will capture a highly variable group. Accuracy of MOS categorization was not acceptable for diagnostic-level tests; however, results support its use as a screening measure for a history of exposure to blast, use in epidemiological studies, and considerations for military policy.

Sleep moderates symptom experience in combat veterans

BACKGROUND

Though sleep disturbance has shown to negatively affect outcomes related to post-deployment conditions, it is unclear whether and how sleep disturbance affects mental health symptoms beyond these conditions. We evaluated the independent and moderating effects of sleep quality on posttraumatic stress disorder (PTSD), depressive, and neurobehavioral symptoms beyond mild traumatic brain injury (TBI) and PTSD diagnosis.

METHODS

Participants were 274 US combat veterans who deployed after 9/11. All completed diagnostic TBI and PTSD interviews and self-report measures of sleep quality, as well as PTSD, depressive, and neurobehavioral symptoms. Only those who passed symptom validity were included in analyses. Hierarchical regression evaluated the contribution of sleep quality to outcomes beyond PTSD and mild TBI. Moderation analyses evaluated interactions between mild TBI, PTSD, and sleep quality on symptom outcomes.

RESULTS

Mild TBI was only significantly associated with PTSD (p = .006) and neurobehavioral (p = .003) symptoms. PTSD diagnosis was associated with PTSD (p < .001), depressive (p < .001), and neurobehavioral symptoms (p < .001) beyond mild TBI. Sleep quality explained additional significant variance in all three outcome measures (p < .001), and also significantly moderated the effects of PTSD diagnosis on neurobehavioral symptoms (ΔR² = .01, p = .023).

LIMITATIONS

Sleep was evaluated subjectively and therefore must be interpreted in this context.

CONCLUSIONS

These results provide support that sleep quality is an independent contributing factor to health outcomes in post-deployment veterans and should be considered in etiology of complaints.

Arterial PaO2 and PaCO2 influence seizure duration in dogs receiving electroconvulsive therapy

The influence of arterial O2 and CO2 tensions on electroconvulsive seizure duration was investigated in five mongrel dogs under consistent anaesthetic conditions. Seizure durations were measured in a randomized protocol of nine possible combinations of arterial gas tension spanning increased, normal or decreased levels of PaO2 and PaCO2. Seizure duration was directly related to PaO2 (p less than 0.00001) and inversely related to PaCO2 (p less than 0.0001). A significant synergism was evident at the extremes of PaO2 and PaCO2, with seizure duration being greater than predicted for hyperoxia-hypocapnia and hypoxia-hypercapnia and shorter than predicted for hypoxia-hypocapnia and hyperoxia-hypercapnia. We conclude that arterial gas tensions strongly influence ECT-induced seizure duration and through this may influence the therapeutic efficacy of electroconvulsive therapy.