Cortical volume abnormalities in posttraumatic stress disorder: an ENIGMA-psychiatric genomics consortium PTSD workgroup mega-analysis.

Studies of posttraumatic stress disorder (PTSD) report volume abnormalities in multiple regions of the cerebral cortex. However, findings for many regions, particularly regions outside commonly studied emotion-related prefrontal, insular, and limbic regions, are inconsistent and tentative. Also, few studies address the possibility that PTSD abnormalities may be confounded by comorbid depression. A mega-analysis investigating all cortical regions in a large sample of PTSD and control subjects can potentially provide new insight into these issues. Given this perspective, our group aggregated regional volumes data of 68 cortical regions across both hemispheres from 1379 PTSD patients to 2192 controls without PTSD after data were processed by 32 international laboratories using ENIGMA standardized procedures. We examined whether regional cortical volumes were different in PTSD vs. controls, were associated with posttraumatic stress symptom (PTSS) severity, or were affected by comorbid depression. Volumes of left and right lateral orbitofrontal gyri (LOFG), left superior temporal gyrus, and right insular, lingual and superior parietal gyri were significantly smaller, on average, in PTSD patients than controls (standardized coefficients = -0.111 to -0.068, FDR corrected P values < 0.039) and were significantly negatively correlated with PTSS severity. After adjusting for depression symptoms, the PTSD findings in left and right LOFG remained significant. These findings indicate that cortical volumes in PTSD patients are smaller in prefrontal regulatory regions, as well as in broader emotion and sensory processing cortical regions.

Accelerated Wound Closure of Deep Partial Thickness Burns with Acellular Fish Skin Graft.

Thermal injuries are caused by exposure to a variety of sources, and split thickness skin grafts are the gold standard treatment for severe burns; however, they may be impossible when there is no donor skin available. Large total body surface area burns leave patients with limited donor site availability and create a need for treatments capable of achieving early and complete coverage that can also retain normal skin function. In this preclinical trial, two cellular and tissue based products (CTPs) are evaluated on twenty-four 5 × 5 deep partial thickness (DPT) burn wounds. Using appropriate pain control methods, DPT burn wounds were created on six anesthetized Yorkshire pigs. Wounds were excised one day post-burn and the bleeding wound beds were subsequently treated with omega-3-rich acellular fish skin graft (FSG) or fetal bovine dermis (FBD). FSG was reapplied after 7 days and wounds healed via secondary intentions. Digital images, non-invasive measurements, and punch biopsies were acquired during rechecks performed on days 7, 14, 21, 28, 45, and 60. Multiple qualitative measurements were also employed, including re-epithelialization, contraction rates, hydration, laser speckle, and trans-epidermal water loss (TEWL). Each treatment produced granulated tissue (GT) that would be receptive to skin grafts, if desired; however, the FSG induced GT 7 days earlier. FSG treatment resulted in faster re-epithelialization and reduced wound size at day 14 compared to FBD (50.2% vs. 23.5% and 93.1% vs. 106.7%, p < 0.005, respectively). No differences in TEWL measurements were observed. The FSG integrated into the wound bed quicker as evidenced by lower hydration values at day 21 (309.7 vs. 2500.4 µS, p < 0.05) and higher blood flow at day 14 (4.9 vs. 3.1 fold change increase over normal skin, p < 0.005). Here we show that FSG integrated faster without increased contraction, resulting in quicker wound closure without skin graft application which suggests FSG improved burn wound healing over FBD.

PEG-Plasma Hydrogels Increase Epithelialization Using a Human Ex Vivo Skin Model.

In vitro cell culture methods are used extensively to study cellular migration, proliferation, and differentiation, which play major roles in wound healing but the results often do not translate to the in vivo environment. One alternative would be to establish an ex vivo model utilizing human discarded skin to evaluate therapies in a more natural setting. The purpose of this study was to institute such a model by creating 'wounds' in the center of a piece of discarded skin and treating them with three different biomaterials: collagen, polyethylene glycol (PEG)-fibrin, or PEG-platelet free plasma (PFP). Explants were cultured for 14 days with supernatant and microscopy images collected every 3 days to assess cytotoxicity and epithelialization. After 14 days, the explants were fixed, sectioned, and stained for cytokeratin-10 (CK-10), alpha-smooth muscle actin (α-SMA), and wheat germ (WG). Compared to controls, similar levels of cytotoxicity were detected for 12 days which decreased slightly at day 14. The PEG-PFP hydrogel-treated wounds epithelialized faster than other treatments at days 6 to 14. A 6-8 cell layer thick CK-10+ stratified epidermis had developed over the PEG-PFP hydrogel and cells co-stained by WG and α-SMA were observed within the hydrogel. An ex vivo model was established that can be used practically to screen different therapies exploring wound healing.

Mitigation of PAH and nitro-PAH emissions from nonroad diesel engines.

More stringent emission requirements for nonroad diesel engines introduced with U.S. Tier 4 Final and Euro Stage IV and V regulations have spurred the development of exhaust aftertreatment technologies. In this study, several aftertreatment configurations consisting of diesel oxidation catalysts (DOC), diesel particulate filters (DPF), Cu zeolite-, and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both Nonroad Transient (NRTC) and Steady (8-mode NRSC) Cycles in order to understand both component and system-level effects of diesel aftertreatment on emissions of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH). Emissions are reported for four configurations including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX. Mechanisms responsible for the reduction, and, in some cases, the formation of PAH and nitro-PAH compounds are discussed in detail, and suggestions are provided to minimize the formation of nitro-PAH compounds through aftertreatment design optimizations. Potency equivalency factors (PEFs) developed by the California Environmental Protection Agency are then applied to determine the impact of aftertreatment on PAH-derived exhaust toxicity. Finally, a comprehensive set of exhaust emissions including criteria pollutants, NO2, total hydrocarbons (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, hopanes and steranes, and metals is provided, and the overall efficacy of the aftertreatment configurations is described. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere.

Temporal Interactions between Maintenance of Cerebral Cortex Thickness and Physical Activity from an Individual Person Micro-Longitudinal Perspective and Implications for Precision Medicine.

Maintenance of brain structure is essential for neurocognitive health. Precision medicine has interests in understanding how maintenance of an individual person's brain, including cerebral cortical structure, interacts with lifestyle factors like physical activity. Cortical structure, including cortical thickness, has recognized relationships with physical activity, but concepts of these relationships come from group, not individual, focused findings. Whether or how group-focused concepts apply to an individual person is fundamental to precision medicine interests but remains unclear. This issue was studied in a healthy man using concurrent micro-longitudinal tracking of magnetic resonance imaging-defined cortical thickness and accelerometer-defined steps/day over six months. These data permitted detailed examination of temporal relationships between thickness maintenance and physical activity at an individual level. Regression analyses revealed graded significant and trend-level temporal interactions between preceding activity vs. subsequent thickness maintenance and between preceding thickness maintenance vs. subsequent activity. Interactions were bidirectional, delayed/prolonged over days/weeks, positive, bilateral, directionally asymmetric, and limited in strength. These novel individual-focused findings in some ways are predicted, but in other ways remain unaddressed or undetected, by group-focused work. We suggest that individual-focused concepts of temporal interactions between maintenance of cortical structure and activity can provide needed new insight for personalized tailoring of physical activity, cortical, and neurocognitive health.

Comparison of Intact Fish Skin Graft and Allograft as Temporary Coverage for Full-Thickness Burns: A Non-Inferiority Study.

The extent and depth of burn injury may mandate temporary use of cadaver skin (allograft) to protect the wound and allow the formation of granulation tissue while split-thickness skin grafts (STSGs) are serially harvested from the same donor areas. However, allografts are not always available and have a high cost, hence the interest in identifying more economical, readily available products that serve the same function. This study evaluated intact fish skin graft (IFSG) as a temporary cover to prepare the wound bed for STSG application. Thirty-six full-thickness (FT) 5 × 5 cm burn wounds were created on the dorsum of six anesthetized Yorkshire pigs on day -1. To mimic the two-stage clinical situation, on day 0, wounds were excised down to a bleeding wound bed and a temporary cover (either IFSG or cadaver porcine skin) was applied; then, on day 7, wounds were debrided to a viable wound bed prior to the application of autologous 1.5:1 meshed STSG (mSTSG). Rechecks were performed on days 14, 21, 28, 45, and 60 with digital images, non-invasive measurements, and punch biopsies. The IFSG created a granulated wound bed receptive to the application of an mSTSG. FT burn wounds treated with an IFSG had similar outcome measures, including contraction rates, trans-epidermal water loss (TEWL) measurements, hydration, and blood perfusion levels, compared to cadaver skin-treated burn wounds. Pathology scoring indicated significant differences between the allograft- and IFSG-treated wounds on day 7, with the IFSG having increased angiogenesis, granulation tissue formation, and immune cells. Pathology scoring indicated no significant differences once mSTSGs were applied to wounds. The IFSG performed as well as cadaver skin as a temporary cover and was not inferior to the standard of care, suggesting the potential to transition IFSGs into clinical use for burns.

Hypothalamus volume mediates the association between adverse childhood experience and PTSD development after adulthood trauma.

The hypothalamus is critical for regulation of the hypothalamic-pituitary-adrenal (HPA) axis and response to stress. Adverse childhood experience (ACE) can affect brain structure, which may contribute to development of posttraumatic stress disorder (PTSD) after subsequent adult trauma. It is unclear, however, if ACE history is particularly associated with aspects of hypothalamic structure which contribute to development of PTSD. To address this issue, the present study longitudinally assessed hypothalamic volumes and their associations with ACE and early post-trauma stress symptoms in subjects who did or did not develop PTSD during 12 months after adult trauma. 109 subjects (18-60 years, F/M = 75/34) completed the PTSD Checklist (PCL) questionnaire for post-trauma stress symptoms, the Childhood Trauma Questionnaire (CTQ) for ACE assessment, and an initial MRI brain scan for hypothalamic volume measurement, within 2 weeks after adult trauma. At post-trauma 12 months, subjects underwent a subsequent PTSD diagnosis interview using the Clinician-Administered PTSD Scale (CAPS), and a follow-up MRI scan. Left and right hypothalamus volumes at 2 weeks after adult trauma negatively correlated with CTQ scores. Right hypothalamus volume at this early time mediated an association between ACE and PTSD symptoms 12 months later. Right hypothalamus volumes also remained persistently smaller from 2 weeks to 12 months after trauma in survivors who developed PTSD. These results suggest that smaller right hypothalamus volume may be related to ACE history in ways that contribute to PTSD development after trauma in adulthood.

Association of age of adverse childhood experiences with thalamic volumes and post-traumatic stress disorder in adulthood.

Background: Adverse childhood experiences (ACEs) have been linked to brain development and mental disorders, however, the impact of the age of occurrence of ACEs on thalamic volume and post-traumatic stress disorder (PTSD) after adult trauma remains unclear. This study assessed associations between ACEs at different ages to thalamic volumes and PTSD development following acute adult trauma. Methods: Seventy-nine adult trauma survivors were recruited immediately after trauma. Within 2 weeks of the traumatic event, participants completed the PTSD Checklist (PCL) to assess PTSD symptoms, the Childhood Trauma Questionnaire (CTQ) and Childhood Age Range Stress Scale (CARSS) to evaluate ACEs and perceived stress level at preschool (<6 years old) and school (6-13 years old) ages, and structural magnetic resonance imaging (sMRI) to measure thalamic volumes. Participants were divided into three groups: those who experienced no childhood trauma or stress (non-ACEs), those who experienced childhood trauma and stress onset at preschool ages (Presch-ACEs), and those who experienced childhood trauma and stress onset at school ages (Sch-ACEs). At 3 months, participants underwent PTSD symptom evaluation using the Clinician Administered PTSD Scale (CAPS). Results: Adult trauma survivors in the Presch-ACEs group had higher CTQ and CAPS scores. In addition, survivors in the Presch-ACEs group had smaller thalamic volume compared to survivors in the non-ACEs and Sch-ACEs groups. Furthermore, smaller thalamic volume moderated a positive association between post-trauma 2-week PCL and subsequent 3-month CAPS scores. Discussion: Earlier occurrence of ACEs was associated with smaller thalamic volume, which appears to moderate a positive association between early posttraumatic stress symptom severity and PTSD development after adult trauma. This raises the possibility that early occurrence of ACEs may impact thalamic structure, specifically a reduction in thalamic volume, and that smaller thalamic volume may contribute to susceptibility to PTSD development after adult trauma.

Evaluation of carcinogenic hazard of diesel engine exhaust needs to consider revolutionary changes in diesel technology.

Diesel engines, a special type of internal combustion engine, use heat of compression, rather than electric spark, to ignite hydrocarbon fuels injected into the combustion chamber. Diesel engines have high thermal efficiency and thus, high fuel efficiency. They are widely used in commerce prompting continuous improvement in diesel engines and fuels. Concern for health effects from exposure to diesel exhaust arose in the mid-1900s and stimulated development of emissions regulations and research to improve the technology and characterize potential health hazards. This included epidemiological, controlled human exposure, laboratory animal and mechanistic studies to evaluate potential hazards of whole diesel exhaust. The International Agency for Research on Cancer (1989) classified whole diesel exhaust as - "probably carcinogenic to humans". This classification stimulated even more stringent regulations for particulate matter that required further technological developments. These included improved engine control, improved fuel injection system, enhanced exhaust cooling, use of ultra low sulfur fuel, wall-flow high-efficiency exhaust particulate filters, exhaust catalysts, and crankcase ventilation filtration. The composition of New Technology Diesel Exhaust (NTDE) is qualitatively different and the concentrations of particulate constituents are more than 90% lower than for Traditional Diesel Exhaust (TDE). We recommend that future reviews of carcinogenic hazards of diesel exhaust evaluate NTDE separately from TDE.

Adverse childhood experiences associate with early post-trauma thalamus and thalamic nuclei volumes and PTSD development in adulthood.

Adverse childhood experiences (ACEs) potentially contribute to posttraumatic stress disorder (PTSD) after adult trauma exposure, but underlying brain changes remain unclear. The present study tested relationships between ACEs, whole thalamus and thalamic nuclei volumes, and post-trauma stress symptoms (PTSS) after adult trauma. Trauma survivors (n = 101) completed the Childhood Trauma Questionnaire (CTQ), the PTSD checklist-special stressor version 5 (PCL), and a structural magnetic resonance imaging (sMRI) scan within post-trauma 2 weeks. At post-trauma 3 months, survivors completed a second PCL survey and a PTSD diagnosis interview using the Clinician-Administered PTSD Scale (CAPS). CTQ scores significantly positively correlated with PCL scores at post-trauma 2 weeks and 3 months (respective p's < 0.01 and < 0.001). CTQ scores significantly negatively correlated with whole thalamus and 7 thalamic nuclei volumes at post-trauma 2 weeks in the PTSD (N = 50), but not the non-PTSD (N = 51) group. Whole thalamus and 22 nuclei volumes significantly negatively correlated with PCL scores at post-trauma 3 months in the PTSD, but not the non-PTSD group. These results suggest ACEs negatively influence early post-trauma thalamic volumes which, in turn, are negatively associated with PTSS in survivors who develop PTSD.

Investigation of PCDD/F emissions from mobile source diesel engines: impact of copper zeolite SCR catalysts and exhaust aftertreatment configurations.

This study investigated the impact of copper zeolite selective catalytic reduction (SCR) catalysts and exhaust aftertreatment configurations on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from mobile source diesel engines. Emissions of PCDD/Fs, reported as the weighted sum of 17 congeners called the toxic equivalency quotient (TEQ), were measured using a modified EPA Method 0023A in the absence and presence of exhaust aftertreatment. Engine-out emissions were measured as a reference, while aftertreatment configurations included various combinations of diesel oxidation catalyst (DOC), diesel particulate filter (DPF), Cu-zeolite SCR, Fe-zeolite SCR, ammonia oxidation catalyst (AMOX), and aqueous urea dosing. In addition, different chlorine concentrations were evaluated. Results showed that all aftertreatment configurations reduced PCDD/F emissions in comparison to the engine-out reference, consistent with reduction mechanisms such as thermal decomposition or combined trapping and hydrogenolysis reported in the literature. Similarly low PCDD/F emissions from the DOC-DPF and the DOC-DPF-SCR configurations indicated that PCDD/F reduction primarily occurred in the DOC-DPF with no noticeable contribution from either the Cu- or Fe-zeolite SCR systems. Furthermore, experiments performed with high chlorine concentration provided no evidence that chlorine content has an impact on the catalytic synthesis of PCDD/Fs for the chlorine levels investigated in this study.

Profiles of precentral and postcentral cortical mean thicknesses in individual subjects over acute and subacute time-scales.

Human precentral and postcentral cortical areas interact to generate sensorimotor functions. Recent imaging work suggests that pre- and postcentral cortical thicknesses of an individual vary over time-scales of years and decades due to aging, disease, and other factors. In contrast, there is little understanding of how thicknesses of these areas vary in an individual over time-scales of minutes and weeks. This study used longitudinal magnetic resonance imaging (MRI) and computational morphometry approaches in 5 healthy subjects to assess how mean thicknesses, and intra- and interhemispheric relationships in mean thicknesses, of these areas vary in an individual subject over minutes and weeks. Within each individual, absolute differences in thicknesses over these times were small and similar in the precentral (mean = 0.02-0.04 mm) and postcentral (mean = 0.03-0.05 mm) areas. Each individual also had a consistent intrahemispheric disparity and interhemispheric asymmetrical or symmetrical relationship in thicknesses of these areas over these times. The results provide new understanding of within-individual cortical thickness variability in these areas and raise the possibility that longitudinal thickness profiling can provide a baseline definition of short time-scale thickness variability that can be used to detect acute and subacute changes in pre- and postcentral thicknesses at an individual subject level.

Interaction of Sleep and Cortical Structural Maintenance From an Individual Person Microlongitudinal Perspective and Implications for Precision Medicine Research.

Sleep and maintenance of brain structure are essential for the continuity of a person's cognitive/mental health. Interestingly, whether normal structural maintenance of the brain and sleep continuously interact in some way over day-week-month times has never been assessed at an individual-person level. This study used unconventional microlongitudinal sampling, structural magnetic resonance imaging, and n-of-1 analyses to assess normal interactions between fluctuations in the structural maintenance of cerebral cortical thickness and sleep duration for day, week, and multi-week intervals over a 6-month period in a healthy adult man. Correlation and time series analyses provided indications of "if-then," i.e., "if" this preceded "then" this followed, sleep-to-thickness maintenance and thickness maintenance-to-sleep bidirectional inverse interactions. Inverse interaction patterns were characterized by concepts of graded influences across nights, bilaterally positive relationships, continuity across successive weeks, and longer delayed/prolonged effects in the thickness maintenance-to-sleep than sleep-to-thickness maintenance direction. These interactions are proposed to involve normal circadian/allostatic/homeostatic mechanisms that continuously influence, and are influenced by, cortical substrate remodeling/turnover and sleep/wake cycle. Understanding interactions of individual person "-omics" is becoming a central interest in precision medicine research. The present n-of-1 findings contribute to this interest and have implications for precision medicine research use of a person's cortical structural and sleep "-omics" to optimize the continuous maintenance of that individual's cortical structure, sleep, and cognitive/mental health.

Enzymatic Debridement of Porcine Burn Wounds via a Novel Protease, SN514.

Necrotic tissue generated by a thermal injury is typically removed via surgical debridement. However, this procedure is commonly associated with blood loss and the removal of viable healthy tissue. For some patients and contexts such as extended care on the battlefield, it would be preferable to remove devitalized tissue with a nonsurgical debridement agent. In this paper, a proprietary debridement gel (SN514) was evaluated for the ability to debride both deep-partial thickness (DPT) and full-thickness burn wounds using an established porcine thermal injury model. Burn wounds were treated daily for 4 days and visualized with both digital imaging and laser speckle imaging. Strip biopsies were taken at the end of the procedure. Histological analyses confirmed a greater debridement of the porcine burn wounds by SN514 than the vehicle-treated controls. Laser speckle imaging detected significant increases in the perfusion status after 4 days of SN514 treatment on DPT wounds. Importantly, histological analyses and clinical observations suggest that SN514 gel treatment did not damage uninjured tissue as no edema, erythema, or inflammation was observed on intact skin surrounding the treated wounds. A blinded evaluation of the digital images by a burn surgeon indicated that SN514 debrided more necrotic tissue than the control groups after 1, 2, and 3 days of treatment. Additionally, SN514 gel was evaluated using an in vitro burn model that used human discarded skin. Treatment of human burned tissue with SN514 gel resulted in greater than 80% weight reduction compared with untreated samples. Together, these data demonstrate that SN514 gel is capable of debriding necrotic tissue and suggest that SN514 gel could be a useful option for austere conditions, such as military multi-domain operations and prolonged field care scenarios.

Longitudinal MRI evaluations of human global cortical thickness over minutes to weeks.

Magnetic resonance imaging (MRI) was used to evaluate within-subject variability in global mean cortical thickness over test-retest intervals of minutes-weeks in five healthy adults. Within-subject measures of global mean thickness were consistent over these intervals. Test-retest assessments of absolute thickness differences and percent thickness differences indicated variations of, respectively, < or =0.05-0.06 mm and < or =+/-1.9-2.3%. There have been few evaluations of normal within-subject variations in cortical thickness. The present results suggest that within-subject variability in global mean cortical thickness can be low over test-retest intervals of minutes-weeks, and that longitudinal scans can establish useful baseline estimates of variability from which to assess changes due to injury, disease, or other experiences.

Relationships in Ongoing Structural Maintenances of the Two Cerebral Cortices of an Individual Brain.

A human brain has separate left and right cerebral cortices, each of which must be continuously structurally maintained during adulthood. There is no understanding of how ongoing structural maintenances of separate parts of a mature individual brain, including the 2 cortices, are related. To explore this issue, this study used an unconventional N-of-1 magnetic resonance imaging time-series paradigm to identify relationships between maintenances of structural thicknesses of the 2 cortices in an adult human brain over week intervals for 6 months. The results suggest that maintenances of left and right cortical thicknesses were symmetrically related in some, but asymmetrically related in other, respects. For matched times, thickness magnitudes and variations on the 2 sides were positively correlated and appeared to reflect maintenance symmetry. Maintenance relationships also extended from earlier to later times with temporal continuity and apparent "if-then" contingencies which were reflected in symmetry and asymmetry dynamics spanning 1- to 2-week periods. The findings suggest concepts of individual brain cortical maintenance symmetry, asymmetry, and temporal continuity dynamics that have not been previously recognized. They have implications for defining cortical maintenance traits or states and for development of N-of-1 precision medicine paradigms that can contribute to understanding individual brain health.

Youth Disclosure of Sexual Orientation to Siblings and Extended Family.

OBJECTIVE: To explore the processes and experiences associated with disclosing sexual orientation to siblings and extended family. BACKGROUND: Few studies prioritize the experience of disclosing to siblings and extended family, despite its frequency and potential impact on the family unit. Extended family members often act as sources of support for youth; it is therefore worthwhile to consider whether this remains true during and after disclosure of sexual orientation. METHOD: Interview and questionnaire data were gathered from 22 lesbian, gay, bisexual, and queer (LGBQ) youth, 14 to 21 years of age, from a large Midwestern city. Constructivist grounded theory informed the qualitative methodology and data analysis. We build on concepts of horizontal and vertical family relationships by also introducing the concept of diagonal relationships. RESULTS: Participants described their relationships with aunts as possessing characteristics of horizontal and vertical relationships, allowing them to act as moderators and mediators of the parent-child relationship. CONCLUSION: The concepts of vertical, horizontal, and diagonal relationships take into consideration how the structure (e.g., hierarchy, egalitarianism, boundaries) and nature (e.g., closeness, reciprocity, mentorship) of various relationships shape the coming-out process for LGBQ youth, without dismissing the importance of either immediate or extended family members. IMPLICATIONS: The emerging conceptualization can guide services and interventions as well as illuminate further research on the family systems of LGBQ youth.

A trial of retrofitted advisory collision avoidance technology in government fleet vehicles.

In-vehicle collision avoidance technology (CAT) has the potential to prevent crash involvement. In 2015, Transport for New South Wales undertook a trial of a Mobileye 560 CAT system that was installed in 34 government fleet vehicles for a period of seven months. The system provided headway monitoring, lane departure, forward collision and pedestrian collision warnings, using audio and visual alerts. The purpose of the trial was to determine whether the technology could change the driving behaviour of fleet vehicle drivers and improve their safety. The evaluation consisted of three components: (1) analysis of objective data to examine effects of the technology on driving behaviour, (2) analysis of video footage taken from a sample of the vehicles to examine driving circumstances that trigger headway monitoring and forward collision warnings, and (3) a survey completed by 122 of the 199 individuals who drove the trial vehicles to examine experiences with, and attitudes to, the technology. Analysis of the objective data found that the system resulted in changes in behaviour with increased headway and improved lane keeping, but that these improvements dissipated once the warning alerts were switched off. Therefore, the system is capable of altering behaviour but only when it is actively providing alerts. In-vehicle video footage revealed that over a quarter of forward collision warnings were false alarms, in which a warning event was triggered despite there being no vehicle travelling ahead. The surveyed drivers recognised that the system could improve safety but most did not wish to use it themselves as they found it to be distracting and felt that it would not prevent them from having a crash. The results demonstrate that collision avoidance technology can improve driving behaviour but drivers may need to be educated about the potential benefits for their driving in order to accept the technology.

Relationship of Hippocampal Volumes and Posttraumatic Stress Disorder Symptoms Over Early Posttrauma Periods.

BACKGROUND: Smaller hippocampal volume is associated with more severe posttraumatic stress disorder (PTSD) symptoms years after traumatic experiences. Posttraumatic stress symptoms appear early following trauma, but the relationship between hippocampal volume and PTSD symptom severity during early posttrauma periods is not well understood. It is possible that the inverse relationship between hippocampal volume and PTSD symptom severity is already present soon after trauma. To test this possibility, we prospectively examined the association between hippocampal volumes and severity of PTSD symptoms within weeks to months after trauma due to a motor vehicle collision. METHODS: Structural magnetic resonance imaging scans of 44 survivors were collected about 2 weeks and again at 3 months after a motor vehicle collision to measure hippocampal volumes. The PTSD Checklist was used to evaluate PTSD symptoms at each scan time. Full (n = 5) or partial (n = 6) PTSD was evaluated using the Clinician-Administered PTSD Scale at 3 months. RESULTS: Left hippocampal volumes at both time points negatively correlated with PTSD Checklist scores, and with subscores for re-experiencing symptoms at 3 months. Left hippocampal volumes at 3 months also negatively correlated with hyperarousal symptoms at 3 months. Finally, neither left nor right hippocampal volumes significantly changed between 2 weeks and 3 months posttrauma. CONCLUSIONS: The results suggest that small hippocampal volume at early posttrauma weeks is associated with increased risk for PTSD development. Furthermore, the inverse relationship between hippocampal volume and PTSD symptoms at 3 months did not arise from posttrauma shifts in hippocampal volume between 2 weeks and 3 months after trauma.