Clinical relevance of subthreshold PTSD versus full criteria PTSD following traumatic brain injury in U.S. service members and veterans

BACKGROUND

The purpose of this cross-sectional study was to examine the influence of subthreshold posttraumatic stress disorder (PTSD) and full PTSD on quality of life following mild traumatic brain injury (mTBI).

METHODS

Participants were 734 service members and veterans (SMV) classified into two injury groups: uncomplicated mild TBI (MTBI; n = 596) and injured controls (IC, n = 139). Participants completed a battery of neurobehavioral measures, 12-or-more months post-injury, that included the PTSD Checklist Civilian version, Neurobehavioral Symptom Inventory, and select scales from the TBI-QOL and MPAI. The MTBI group was divided into three PTSD subgroups: No-PTSD (n = 266), Subthreshold PTSD (n = 139), and Full-PTSD (n = 190).

RESULTS

There was a linear relationship between PTSD severity and neurobehavioral functioning/quality of life in the MTBI sample. As PTSD severity increased, significantly worse scores were found on 11 of the 12 measures (i.e.

, MTBI

Full-PTSD > Sub-PTSD > No-PTSD). When considering the number of clinically elevated scores, a linear relationship between PTSD severity and neurobehavioral functioning/quality of life was again observed in the MTBI sample (e.g., 3-or-more elevated scores: Full-PTSD = 92.1 %, Sub-PTSD = 61.9 %, No-PTSD = 19.9 %).

LIMITATIONS

Limitations included the use of a self-report measure to determine diagnostic status that may under/overcount or mischaracterize individuals.

CONCLUSION

PTSD symptoms, whether at the level of diagnosable PTSD, or falling short of that because of the intensity or characterization of symptoms, have a significant negative impact on one's quality of life following MTBI. Clinicians' treatment targets should focus on the symptoms that are most troubling for an individual and the individual's perception of quality of life, regardless of the diagnosis itself.

Elevated Serum Tau and UCHL-1 Concentrations Within 12 Months of Injury Predict Neurobehavioral Functioning 2 or More Years Following Traumatic Brain Injury: A Longitudinal Study

OBJECTIVE

Blood-based biomarkers have received considerable attention for their diagnostic and prognostic value in the acute and postacute period following traumatic brain injury (TBI). The purpose of this study was to examine whether blood-based biomarker concentrations within the first 12 months of TBI can predict neurobehavioral outcome in the chronic phase of the recovery trajectory.

SETTING

Inpatient and outpatient wards from 3 military medical treatment facilities.

PARTICIPANTS

A total of 161 service members and veterans classified into 3 groups: ( a ) uncomplicated mild TBI (MTBI; n = 37), ( b ) complicated mild, moderate, severe, penetrating TBI combined (STBI; n = 46), and ( c ) controls (CTRL; n = 78).

DESIGN

Prospective longitudinal.

MAIN MEASURES

Participants completed 6 scales from the Traumatic Brain Injury Quality of Life (ie, Anger, Anxiety, Depression, Fatigue, Headaches, and Cognitive Concerns) within 12 months (baseline) and at 2 or more years (follow-up) post-injury. Serum concentrations of tau, neurofilament light, glial fibrillary acidic protein, and UCHL-1 at baseline were measured using SIMOA.

RESULTS

Baseline tau was associated with worse anger, anxiety, and depression in the STBI group at follow-up ( R2 = 0.101-0.127), and worse anxiety in the MTBI group ( R2 = 0.210). Baseline ubiquitin carboxyl-terminal hydrolase L1 (UCHL-1) was associated with worse anxiety and depression at follow-up in both the MTBI and STBI groups ( R2 Δ = 0.143-0.207), and worse cognitive concerns in the MTBI group ( R2 Δ = 0.223).

CONCLUSIONS

A blood-based panel including these biomarkers could be a useful tool for identifying individuals at risk of poor outcome following TBI.

Women Report Worse Neurobehavioral Symptoms than Men following Mild Traumatic Brain Injury in U.S. Military Service Members

Women are more directly involved in combat operations today than ever before, currently making up 18.6% of officers and 16.8% of enlisted personnel in the US military. However, women continue to be underrepresented in military research. Studies which do consider gender differences in traumatic brain injury (TBI) outcomes have shown that women report significantly more post-concussive symptoms compared to men. Conclusions for true gender differences related to TBI is hard to make without controlling for non-TBI factors. The objective of this study was to examine the effects of gender specific to mild TBI (MTBI) sequelae from injured and non-injured control groups and investigate the role of PTSD in symptom reporting. It should be noted that the terms gender and men/women are used in this paper in place of sex or males/females given we are not discussing biological attributes. A total of 966 U.S. military service members and veterans where include in the study. Of the total sample, 455 men and 46 women where in the MTBI group, 285 men and 31 women in the Injured Controls group (IC), 111 men and 38 women in the Non-injured Controls group (NIC). Postconcussive and quality of life symptoms were compared for men and women while controlling for combat exposure. MTBI and IC groups were also stratified by PTSD presentation. Measures used included the Neurobehavioral Symptom Inventory (NSI), PTSD Checklist (PCL-C), Traumatic Brain Injury Quality of Life (TBI-QOL), and Combat Exposure Scale. In the MTBI group, women had worse scores on NSI total, NSI Somatosensory and Affective clusters; and the TBI-QOL Anxiety, Fatigue, and Headache scales (n2=.018 to .032, small to small-medium effect sizes). When PTSD was present, women had worse scores on the NSI Somatosensory cluster only (n2=.029, small-medium effect size). In contrast, when PTSD was absent, women had worse scores on the NSI Somatosensory and Affective clusters, and the TBI-QOL Anxiety and Headache scales compared to men (n2=.032 to .063, small to medium effect sizes). In the IC group, women had worse scores on the NSI Cognitive cluster and the TBI-QOL Fatigue and Pain Interference scales (n2=.024 to .042, small to small-medium effect sizes). However, group differences were no longer found when stratified by PTSD sub-groups. In the NIC group, there were no significant group differences for all analyses. We were able to identify symptoms unique to women recovering from MTBI which were not present following other forms of physical injury or healthy controls. However, the impact of PTSD exacerbates the symptom profile and its comorbidity with MTBI equates most of the noted gender differences.

Cumulative Blast Exposure During a Military Career Negatively Impacts Recovery from Traumatic Brain Injury

Sub-concussive injuries have emerged as an important factor in the long-term brain health of athletes and military personnel. The objective of this study was to explore the relationship between service member and veterans (SMVs) lifetime blast exposure and recovery from a traumatic brain injury (TBI). A total of 558 SMVs with a history of TBI were examined. Lifetime blast exposure (LBE) was based on self-report (M = 79.4, standard deviation = 392.6; range = 0-7500) categorized into three groups: Blast Naive (n = 121), Low LBE (n = 223; LBE range 1-9), and High LBE (n = 214; LBE >10). Dependent variables were the Neurobehavioral Symptom Inventory (NSI) and Post-traumatic Stress Disorder Checklist-Civilian (PCL-C) and the Traumatic Brain Injury Quality of Life (TBI-QOL). Analyses controlled for demographic factors (age, gender, and race) as well as TBI factors (months since index TBI, index TBI severity, and total number lifetime TBIs). The Blast Naive group had significantly lower NSI and PCL-C scores compared with the Low LBE group and High LBE group, with small to medium effect sizes. On the TBI-QOL, the Blast Naïve group had better quality life on 10 of the 14 scales examined. The Low LBE did not differ from the High LBE group on the PCL-C, NSI, or TBI-QOL. Blast exposure over an SMV's career was associated with increased neurobehavioral and post-traumatic stress symptoms following a TBI. The influence of psychological trauma associated with blasts may be an important factor influencing symptoms as well as the accuracy of self-reported estimates of LBE.

High Lifetime Blast Exposure Using the Blast Exposure Threshold Survey Is Associated With Worse Warfighter Brain Health Following Mild Traumatic Brain Injury

The purpose of this study was to extend previous research by examining the relationship between lifetime blast exposure and neurobehavioral functioning after mild TBI (MTBI) by (a) using a comprehensive measure of lifetime blast exposure, and (b) controlling for the influence of post-traumatic stress disorder (PTSD). Participants were 103 United States service members and veterans (SMVs) with a medically documented diagnosis of MTBI, recruited from three military treatment facilities (74.8%) and community-based recruitment initiatives (25.2%, e.g., social media, flyers). Participants completed a battery of neurobehavioral measures 12 or more months post-injury (Neurobehavioral Symptom Inventory, PTSD-Checklist PCLC, TBI-Quality of Life), including the Blast Exposure Threshold Survey (BETS). The sample was classified into two lifetime blast exposure (LBE) groups: High (n = 57) and Low (n = 46) LBE. In addition, the sample was classified into four LBE/PTSD subgroups: High PTSD/High LBE (n = 38); High PTSD/Low LBE (n = 19); Low PTSD/High LBE (n = 19); and Low PTSD/Low LBE (n = 27). The High LBE group had consistently worse scores on all neurobehavioral measures compared with the Low LBE group. When controlling for the influence of PTSD (using ANCOVA), however, only a handful of group differences remained. When comparing measures across the four LBE/PTSD subgroups, in the absence of clinically meaningful PTSD symptoms (i.e., Low PTSD), participants with High LBE had worse scores on the majority of neurobehavioral measures (e.g., post-concussion symptoms, sleep, fatigue). When examining the total number of clinically elevated measures, the High LBE subgroup consistently had a greater number of clinically elevated scores compared with the Low LBE subgroup for the majority of comparisons (i.e., four to 15 or more elevated symptoms). In contrast, in the presence of clinically meaningful PTSD symptoms (i.e., High PTSD), there were no differences between High versus Low LBE subgroups for all measures. When examining the total number of clinically elevated measures, however, there were meaningful differences between High versus Low LBE subgroups for those comparisons that included a high number of clinically elevated scores (i.e., six to 10 or more), but not for a low number of clinically elevated scores (i.e., one to five or more). High LBE, as quantified using a more comprehensive measure than utilized in past research (i.e., BETS), was associated with worse overall neurobehavioral functioning after MTBI. This study extends existing literature showing that lifetime blast exposure, that is largely subconcussive, may negatively impact warfighter brain health and readiness beyond diagnosable brain injury.

Impact of depression and post-traumatic stress on manual and oculomotor performance in service members with a history of mild TBI

OBJECTIVE

To determine the impact of depression and post-traumatic stress on an automated oculomotor and manual measure of visual attention, compared to conventional neuropsychological assessment. Setting: Military traumatic brain injury (TBI) rehabilitation program.

PARTICIPANTS

188 Active Duty Service Members (ADSM) with a history of mild TBI.

DESIGN

A cross-sectional and correlational study with data obtained through an IRB-approved data registry study. Main measures: Bethesda Eye & Attention Measure (BEAM); brief neuropsychological battery; self-reported symptom surveys including Neurobehavioral Symptom Inventory (NSI), Patient Health Questionnaire-8 (PHQ-8), and PTSD Checklist-5 (PCL-5).

RESULTS

Small effect sizes were found for partial correlations between both depression and post-traumatic stress and key BEAM metrics. In contrast, small-to-medium effects sizes were found across all traditional neuropsychological test measures.

CONCLUSION

This study illustrates the profile of impairments associated with depression and post-traumatic stress on saccadic eye movements and manual responses to BEAM relative to conventional neuropsychological tests. Results demonstrated that among ADSM seen for mTBI, depression and PTS exert a significant negative impact on measures of processing speed, attention, executive function, and memory across saccadic, manual, and conventional neuropsychological tests. However, the unique psychometric features of each of these assessment approaches may assist in distinguishing the effects of psychiatric comorbidities within this population.

Associations of mTBI and post-traumatic stress to amygdala structure and functional connectivity in military Service Members

INTRODUCTION

Traumatic brain injury (TBI) is one of the highest public health priorities, especially among military personnel where comorbidity with post-traumatic stress symptoms and resulting consequences is high. Brain injury and post-traumatic stress symptoms are both characterized by dysfunctional brain networks, with the amygdala specifically implicated as a region with both structural and functional abnormalities.

METHODS

This study examined the structural volumetrics and resting state functional connectivity of 68 Active Duty Service Members with or without chronic mild TBI (mTBI) and comorbid symptoms of Post-Traumatic Stress (PTS).

RESULTS AND DISCUSSION

Structural analysis of the amygdala revealed no significant differences in volume between mTBI and healthy comparison participants with and without post-traumatic stress symptoms. Resting state functional connectivity with bilateral amygdala revealed decreased anterior network connectivity and increased posterior network connectivity in the mTBI group compared to the healthy comparison group. Within the mTBI group, there were significant regions of correlation with amygdala that were modulated by PTS severity, including networks implicated in emotional processing and executive functioning. An examination of a priori regions of amygdala connectivity in the default mode network, task positive network, and subcortical structures showed interacting influences of TBI and PTS, only between right amygdala and right putamen. These results suggest that mTBI and PTS are associated with hypo-frontal and hyper-posterior amygdala connectivity. Additionally, comorbidity of these conditions appears to compound these neural activity patterns. PTS in mTBI may change neural resource recruitment for information processing between the amygdala and other brain regions and networks, not only during emotional processing, but also at rest.

Risk factors for the presence and persistence of posttraumatic stress symptoms following traumatic brain injury in U.S. service members and veterans

This study aimed to identify risk factors predictive of the presence and persistence of posttraumatic stress disorder (PTSD) symptom reporting following traumatic brain injury (TBI). Participants were 1,301 U.S. service members and veterans (SMVs) divided into four groups: uncomplicated mild TBI (mTBI; n = 543); complicated mild, moderate, severe, and penetrating TBI (n = 230); injured controls (n = 340); and noninjured controls (n = 188). We examined 25 factors related to demographic, injury-related, military-specific, treatment/health care need, and mental health/social support variables. Seven factors were statistically associated with the presence of DSM-IV-TR symptom criteria for PTSD: premorbid IQ, combat exposure, depression, social participation, history of mTBI, need for managing mood and stress, and need for improving memory and attention, p < .001 (51.3% variance). When comparing the prevalence of these risk factors in a longitudinal cohort (n = 742) across four PTSD trajectory groups (i.e., asymptomatic, improved, developed, persistent), a higher proportion of participants in the persistent PTSD group reported worse depression, a lack of social participation, and history of mTBI. Additionally, a higher proportion of participants in the persistent and developed PTSD groups reported the need for managing mood/stress and improving memory/attention. When considered simultaneously, the presence of ≥ 1 or ≥ 2 risk factors was associated with a higher proportion of participants in the developed and persistent PTSD groups, ps < .001. These risk factors may be useful in identifying SMVs at risk for the development and/or persistence of PTSD symptoms who may need intervention.

A-15 Impact of Lifetime Blast Exposure on Cognitive and Psychiatric Functioning of Warfighters

Objective: Some military occupation specialties (MOS) such as Special Forces are at high risk for lifetime blast exposure (LBE). These individuals are at risk for some medical conditions but the impact of LBE on service members and veterans (SMVs) cognitive and psychiatric function is unknown.

Methods: 281 SMVs completed an assessment of Attention/Working Memory, Processing Speed, Executive Function, Memory, and Psychiatric function. Average age was 35.86 (SD = 9.84) and 61.2% had at least moderate combat exposure and 32.4% had no history of traumatic brain injury (TBI). 61 participants had no LBE, 113 were in a high-risk MOS and had LBE (M = 211.23, SD = 395.1), and 107 were not in a high-risk MOS but had LBE (M = 92.7, SD =222.9).

Results: Cognitively, a small effect for LBE was observed on Processing Speed (p = 0.015, ηp2 = 0.037), but not for the other domains. Psychiatrically, a medium effect was observed (p &lt; 0.001, ηp2 = 0.103). Higher LBE was associated with Somatic Complaints, Low Positive Emotions and Aberrant Experiences. However, after controlling for covariates (sex, ethnicity, post-traumatic stress, combat exposure, alcohol use, and TBI) there was no impact of LBE.

Conclusion: LBE may negatively impact processing speed and psychiatric function; however, the relative impact of LBE compared to other factors such as post-traumatic stress, substance abuse, and TBI needs further investigation. The views expressed are those of the authors and do not necessarily represent the official policy or position of the Defense Health Agency or any other U.S. government agency. For more information contact dha.TBICOEinfo@mail.mil. UNCLASSIFIED.

Low resilience following traumatic brain injury is strongly associated with poor neurobehavioral functioning in U.S. military service members and veterans

OBJECTIVE

The purpose of this study was to examine the relationship between resilience and self-reported neurobehavioral functioning following traumatic brain injury (TBI) in U.S. military service members and veterans (SMVs). A secondary objective was to examine the interaction between resilience and posttraumatic stress disorder (PTSD) on neurobehavioral functioning.

METHOD

Participants included 795 SMVs classified into four groups: Uncomplicated Mild TBI (MTBI; n=300); Complicated Mild, Moderate, Severe, or Penetrating TBI (STBI, n 162); Injured Controls (IC, n=185); and Non-injured Controls (NIC, n=148). Two independent cohorts were evaluated - those assessed within 1-year of injury and those assessed 10-years post-injury. SMVs completed self-report measures including the PTSD Checklist-Civilian version, Neurobehavioral Symptom Inventory, and TBI-Quality of Life.

RESULTS

Results showed that (1) lower resilience was strongly associated with poorer neurobehavioral functioning across all groups at 1-year and 10-years post-injury, and (2) PTSD and resilience had a robust influence on neurobehavioral functioning at both time periods post-injury, such that SMVs with PTSD and low resilience displayed the poorest neurobehavioral functioning.

CONCLUSION

Results suggest that regardless of injury group and time since injury, resilience and PTSD strongly influence neurobehavioral functioning following TBI among SMVs. Future research evaluating interventions designed to enhance resilience in this population is indicated.

A-130 Validity-10, Remaining-12 and Total NSI Scores as Measures of Symptom Validity in Service Members with a History of mTBI

Objective

The Neurobehavioral Symptom Inventory (NSI), a commonly used self-report measure of concussive symptoms, is frequently employed throughout the Defense Health Agency. Embedded measures of symptom validity have been developed that include the Validity-10 and total NSI score. A recent investigation in a small sample of veterans (n = 45) suggested that the 12 items on the NSI that do not contribute to the Validity-10 (Remaining-12) perform in a manner similar to the Validity-10. The current study sought to evaluate the classification accuracy of the Validity-10, Remaining-12 and total NSI score in a larger sample to assess the relative utility of each.

Method

The NSI and MMPI-2-RF scores of 255 active duty Service Members and Veterans seen ≥4 months after mild Traumatic Brain Injury (mTBI) were evaluated. MMPI-2-RF criterion were defined as over-reporting (&gt;79 on Fs, RBS, and/or FBS-r; &gt;78 on F-r; &gt;69 on Fp-r) and invalid (&gt;119 on F; &gt;99 on all other scales).

Results

Correlations between all MMPI-2-RF over-report scales and the Validity-10, Remaining-12, and NSI total were roughly commensurate and significant at the p &lt; 0.001 level. AUC values for the RF over-report protocols were as followings: Validity-10 = 0.87, Remaining-12 = 0.89, NSI total = 0.89. AUC values for invalid RF protocols were as follows: Validity-10 = 0.91, Remaining-12 = 0.92, NSI total = 0.93.

Conclusions

The current findings indicate reasonable and equivalent classification accuracies for the Validity-10, Remaining-12, and NSI total score. These data can be taken to suggest that there is limited uniqueness of the Validity-10 relative to the remaining NSI items.

Sleep disturbances following traumatic brain injury are associated with poor neurobehavioral outcomes in U.S. military service members and veterans

STUDY OBJECTIVES

This study examined whether sleep disturbances were associated with neurobehavioral outcome following a traumatic brain injury (TBI) in a well characterized group of service members and veterans.

METHODS

Six-hundred and six participants were enrolled into the Defense and Veterans Brain Injury Center, 15-Year Longitudinal TBI study. All participants completed a battery of tests measuring self-reported sleep disturbances, neurobehavioral symptoms, and Posttraumatic Stress Disorder PTSD symptoms. Data were analyzed using analysis of variance with post-hoc comparisons. Four groups were analyzed separately: uncomplicated mild TBI (MTBI); complicated mild, moderate, severe, or penetrating - combined TBI (CTBI); injured controls (IC, i.e., orthopedic or soft-tissue injury without TBI); and non-injured controls (NIC).

RESULTS

A higher proportion of the MTBI group reported moderate-severe sleep disturbances (66.5%) compared to the IC (54.9%), CTBI (47.5%), and NIC groups (34.3%). Participants classified as having Poor Sleep had significantly worse scores on the majority of TBI-QOL scales compared to those classified as having Good Sleep, regardless of TBI severity or the presence of TBI. There was a significant interaction between sleep disturbances and PTSD. While sleep disturbances and PTSD by themselves were significant factors associated with worse outcome, both factors combined resulted in worse outcome than either singularly.

CONCLUSIONS

Regardless of group (injured or NIC), sleep disturbances were common and were associated with significantly worse neurobehavioral functioning. When experienced concurrently with PTSD, sleep disturbances pose significant burden to service members and veterans.

Enhancing behavioral sleep care with digital technology: study protocol for a hybrid type 3 implementation-effectiveness randomized trial

BACKGROUND

Insomnia affects almost one in four military service members and veterans. The first-line recommended treatment for insomnia is cognitive-behavioral therapy for insomnia (CBTI). CBTI is typically delivered in-person or online over one-to-four sessions (brief versions) or five-to-eight sessions (standard versions) by a licensed doctoral or masters-level clinician with extensive training in behavioral sleep medicine. Despite its effectiveness, CBTI has limited scalability. Three main factors inhibit access to and delivery of CBTI including restricted availability of clinical expertise; rigid, resource-intensive treatment formats; and limited capacities for just-in-time monitoring and treatment personalization. Digital technologies offer a unique opportunity to overcome these challenges by providing scalable, personalized, resource-sensitive, adaptive, and cost-effective approaches for evidence-based insomnia treatment.

METHODS

This is a hybrid type 3 implementation-effectiveness randomized trial using a scalable evidence-based digital health software platform, NOCTEM™'s Clinician-Operated Assistive Sleep Technology (COAST™). COAST includes a clinician portal and a patient app, and it utilizes algorithms that facilitate detection of sleep disordered patterns, support clinical decision-making, and personalize sleep interventions. The first aim is to compare three clinician- and system-centered implementation strategies on the reach, adoption, and sustainability of the COAST digital platform by offering (1) COAST only, (2) COAST plus external facilitation (EF: assistance and consultation to providers by NOCTEM's sleep experts), or (3) COAST plus EF and internal facilitation (EF/IF: assistance/consultation to providers by NOCTEM's sleep experts and local champions). The second aim is to quantify improvements in insomnia among patients who receive behavioral sleep care via the COAST platform. We hypothesize that reach, adoption, and sustainability and the magnitude of improvements in insomnia will be superior in the EF and EF/IF groups relative to the COAST-only group.

DISCUSSION

Digital health technologies and machine learning-assisted clinical decision support tools have substantial potential for scaling access to insomnia treatment. This can augment the scalability and cost-effectiveness of CBTI without compromising patient outcomes. Engaging providers, stakeholders, patients, and decision-makers is key in identifying strategies to support the deployment of digital health technologies that can promote quality care and result in clinically meaningful sleep improvements, positive systemic change, and enhanced readiness and health among service members.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04366284 . Registered on 28 April 2020.

A-10 Self-Reported Post-Concussive Symptom Levels as Predictors of Performance Validity in a Sample of Active Duty Service Members with a History of Mild Traumatic Brain Injury

Objective

The study investigated the relationship between levels of symptom reporting and performance validity testing (PVT) in Active Duty Service Members (ADSM) with mild traumatic brain injury (mTBI).

Method

A total of 70 ADSM with a history of mTBI completed the Neurobehavioral Symptom Inventory (NSI); the PTSD Check List for DSM-5 (PCL-5), Headache Impact Test (HIT-6), Patient Health Questionnaire (PHQ8), Pittsburgh Sleep Quality Index (PSQI), and Alcohol Use Disorders Identification Test (AUDIT-C); and a comprehensive neuropsychological evaluation including the Test of Memory Malingering (TOMM). A multiple regression was conducted with all self-reported symptom questionnaires as predictors of PVT performance. To further explore this relationship, the four NSI subscales (affective, cognitive, vestibular, somatosensory) plus the mild Brain Injury Atypical Symptoms (mBIAS) subscore were entered into a separate regression analysis.

Results

The NSI was the only significant predictor of TOMM Trial 1 performance (TOMMT1; R2 = .272, F(6,58) = 3.606, p &lt; .01; β = −.615, p &gt; .01). When the four NSI subscales (affective, cognitive, vestibular, somatosensory) plus the mild Brain Injury Atypical Symptoms (mBIAS) subscore were entered into a separate regression analysis, only the somatosensory subscore emerged as a significant predictor of TOMMT1 (R2 = .208, F(5,63) = 3.317, p &lt; .05; β = −.384, p &gt; .05).

Conclusions

Results suggest that performance validity measures in ADSM with mTBI may at times be more strongly influenced by patients’ health concerns than by overt dissimulation.

Disease risk analysis: a tool for primate conservation planning and decision making

Concern about emerging and re-emerging diseases plays an increasing role in conservation and management of both captive and free-ranging nonhuman primates (NHPs). Managers and policy makers must formulate conservation plans in an arena plagued by uncertainty, complexity, emotion, and politics. The risk analysis paradigm provides a framework that brings together scientists and policy experts to make better decisions for both people and animals. Risk analysis is a multidisciplinary, science-based process that provides an organized and logical approach for incorporating scientific information into policy development in the real world. By blending four specific goal-oriented stages-hazard identification, risk assessment, risk management, and risk communication-one can logically assess the probability that an adverse event, such as the introduction of an emerging disease into a naïve population, will occur. The following is a review of this process as it pertains to NHP conservation and risks associated with infectious diseases.

Ecological relationships between the prevalence of cattle shedding Escherichia coli O157:H7 and characteristics of the cattle or conditions of the feedlot pen

This study was designed to describe the percentage of cattle shedding Escherichia coli O157:H7 in Midwestern U.S. feedlots and to discover relationships between the point prevalence of cattle shedding the organism and the characteristics of those cattle or the conditions of their pens. Cattle from 29 pens of five Midwestern feedlots were each sampled once between June and September 1999. Feces were collected from the rectum of each animal in each pen. Concurrently, samples of water were collected from the water tank, and partially consumed feed was collected from the feedbunk of each pen. Characteristics of the cattle and conditions of each pen that might have affected the prevalence of cattle shedding E. coli O157:H7 were recorded. These factors included the number of cattle; the number of days on feed; and the average body weight, class, and sex of the cattle. In addition, the temperature and pH of the tank water were determined, and the cleanliness of the tank water and the condition of the pen floor were subjectively assessed. The samples of feces, feed, and water were tested for the presence of E. coli O157:H7. E. coli O157:H7 was isolated from the feces of 719 of 3,162 cattle tested (23%), including at least one animal from each of the 29 pens. The percentage of cattle in a pen shedding E. coli O157:H7 did not differ between feedyards, but it did vary widely within feedyards. A higher prevalence of cattle shed E. coli O157:H7 from muddy pen conditions than cattle from pens in normal condition. The results of this study suggest that E. coli O157:H7 should be considered common to groups of feedlot cattle housed together in pens and that the condition of the pen floor may influence the prevalence of cattle shedding the organism.

High prevalence of antibodies to Neospora caninum in white-tailed deer (Odocoileus virginianus)

Serum samples of 400 white-tailed deer (Odocoileus virginianus) from 16 preserves in northeastern Illinois were tested for Neospora caninum antibodies in the N. caninum agglutination test using mouse-derived N. caninum tachyzoites and mercaptoethanol. Antibodies were found in 162 deer with titres of 1:40 (47 deer), 1:80 (32 deer), 1:160 (17 deer), 1:200 (eight deer), 1:400 (19 deer), 1:800 (17 deer) and > or = 1:1600 (22 deer). There were no significant differences in prevalence between age or sex of the deer. The high prevalence of N. caninum infection in deer is consistent with a sylvatic cycle of N. caninum.