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Understanding characteristics of healthcare personnel (HCP) with SARS-CoV-2 infection supports the development and prioritization of interventions to protect this important workforce. We report detailed characteristics of HCP who tested positive for SARS-CoV-2 from April 20, 2020 through December 31, 2021.
Methods:
CDC collaborated with Emerging Infections Program sites in 10 states to interview HCP with SARS-CoV-2 infection (case-HCP) about their demographics, underlying medical conditions, healthcare roles, exposures, personal protective equipment (PPE) use, and COVID-19 vaccination status. We grouped case-HCP by healthcare role. To describe residential social vulnerability, we merged geocoded HCP residential addresses with CDC/ATSDR Social Vulnerability Index (SVI) values at the census tract level. We defined highest and lowest SVI quartiles as high and low social vulnerability, respectively.
Results:
Our analysis included 7,531 case-HCP. Most case-HCP with roles as certified nursing assistant (CNA) (444, 61.3%), medical assistant (252, 65.3%), or home healthcare worker (HHW) (225, 59.5%) reported their race and ethnicity as either non-Hispanic Black or Hispanic. More than one third of HHWs (166, 45.2%), CNAs (283, 41.7%), and medical assistants (138, 37.9%) reported a residential address in the high social vulnerability category. The proportion of case-HCP who reported using recommended PPE at all times when caring for patients with COVID-19 was lowest among HHWs compared with other roles.
Conclusions:
To mitigate SARS-CoV-2 infection risk in healthcare settings, infection prevention, and control interventions should be specific to HCP roles and educational backgrounds. Additional interventions are needed to address high social vulnerability among HHWs, CNAs, and medical assistants.
To characterize residential social vulnerability among healthcare personnel (HCP) and evaluate its association with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection.
Design:
Case–control study.
Setting:
This study analyzed data collected in May–December 2020 through sentinel and population-based surveillance in healthcare facilities in Colorado, Minnesota, New Mexico, New York, and Oregon.
Participants:
Data from 2,168 HCP (1,571 cases and 597 controls from the same facilities) were analyzed.
Methods:
HCP residential addresses were linked to the social vulnerability index (SVI) at the census tract level, which represents a ranking of community vulnerability to emergencies based on 15 US Census variables. The primary outcome was SARS-CoV-2 infection, confirmed by positive antigen or real-time reverse-transcriptase– polymerase chain reaction (RT-PCR) test on nasopharyngeal swab. Significant differences by SVI in participant characteristics were assessed using the Fisher exact test. Adjusted odds ratios (aOR) with 95% confidence intervals (CIs) for associations between case status and SVI, controlling for HCP role and patient care activities, were estimated using logistic regression.
Results:
Significantly higher proportions of certified nursing assistants (48.0%) and medical assistants (44.1%) resided in high SVI census tracts, compared to registered nurses (15.9%) and physicians (11.6%). HCP cases were more likely than controls to live in high SVI census tracts (aOR, 1.76; 95% CI, 1.37–2.26).
Conclusions:
These findings suggest that residing in more socially vulnerable census tracts may be associated with SARS-CoV-2 infection risk among HCP and that residential vulnerability differs by HCP role. Efforts to safeguard the US healthcare workforce and advance health equity should address the social determinants that drive racial, ethnic, and socioeconomic health disparities.
Innovation Concept: EM Sim Cases is an innovative, open-access website that was created in 2015 to publish medical simulation resources including standardized, peer-reviewed simulation cases. Herein we describe our interim analysis. Methods: We performed a massive online needs assessment using a methodology previously described by Chan et. al. to determine how we can shape EM Sim Cases to meet the needs of learners and educators who use it. We engaged with simulation experts from the Emergency Medicine Simulation Education Research Collaborative to design a Google Forms survey using best practices in survey design. We distributed the survey to our target community of practice via Twitter, email, and a blog post published on emsimcases.com. Curriculum, Tool, or Material: We received 81 responses from simulation educators representing 8 medical specialties and 13 countries. Most survey respondents identified themselves as staff physicians (n = 44) and specialized in emergency medicine (n = 39). They had 0-21+ years of experience. 37% of respondents (n = 30) stated that material from EM Sim Cases makes up 25% or more of their simulation curriculum. Several respondents noted that using this content made them feel more confident and more current. Respondents praised EM Sim Cases for a well-organized case format, the proper level of detail, consistency between case designs, and the wide variety of cases. Suggested improvements included an opportunity to directly comment on cases and more cases in pediatric, rural, and advanced airway management situations. Suggestions were made to improve the navigability of the website. Respondents wanted to see additional blog content on debriefing strategies and self-made task/skill trainers. Conclusion: EM Sim Cases is a novel, free open-access simulation resource. Using a massive online needs assessment we were able to determine future directions including case topics, website reorganization, and educational material. We were also able to capture how impactful a resource like this can be to clinical and educational practice outside of the simulation setting.
Introduction: In 2018, Canadian postgraduate specialist Emergency Medicine (EM) programs began implementing a competency-based medical education (CBME) assessment system. To support improvement of this assessment program, we sought to evaluate its short-term educational outcomes nationally and within individual programs. Methods: Program-level data from the 2018 resident cohort were amalgamated and analyzed. The number of Entrustable Professional Activity (EPA) assessments (overall and for each EPA) and the timing of resident promotion through program stages was compared between programs and to the guidelines provided by the national EM specialty committee. Total EPA observations from each program were correlated with the number of EM and pediatric EM rotations. Results: Data from 15 of 17 (88.2%) EM programs containing 9,842 EPA observations from 68 of the 77 (88.3%) Canadian EM specialist residents in the 2018 cohort were analyzed. The average number of EPAs observed per resident in each program varied from 92.5 to 229.6 and correlated strongly with the number of blocks spent on EM and pediatric EM (r = 0.83, p < 0.001). Relative to the guidelines outlined by the specialty committee, residents were promoted later than expected and with fewer EPA observations than suggested. Conclusion: We present a new approach to the amalgamation of national and program-level assessment data. There was demonstrable variation in both EPA-based assessment numbers and promotion timelines between programs and with national guidelines. This evaluation data will inform the revision of local programs and national guidelines and serve as a starting point for further reaching outcome evaluation. This process could be replicated by other national assessment programs.
Innovation Concept: A major barrier to the development of a national simulation case repository and multi-site simulation research is the lack of a standardized national case template. This issue was recently identified as a priority research topic for Canadian simulation based education (SBE) research in emergency medicine (EM). We partnered with the EM Simulation Education Researchers Collaborative (EM-SERC) to develop a national simulation template. Methods: The EM Sim Cases template was chosen as a starting point for the consensus process. We generated feedback on the template using a three-phase modified nominal group technique. Members of the EM-SERC mailing list were consulted, which included 20 EM simulation educators from every Canadian medical school except Northern Ontario School of Medicine and Memorial University. When comments conflicted, the sentiment with more comments in favour was incorporated. Curriculum, Tool or Material: In phase one we sought free-text feedback on the EM Sim Cases template via email. We received 65 comments from 11 respondents. An inductive thematic analysis identified four major themes (formatting, objectives, debriefing, and assessment tools). In phase two we sought free-text feedback on the revised template via email. A second thematic analysis on 40 comments from 12 respondents identified three broad themes (formatting, objectives, and debriefing). In phase three we sought feedback on the penultimate template via focus groups with simulation educators and technologists at multiple Canadian universities. This phase generated 98 specific comments which were grouped according to the section of the template being discussed and used to develop the final template (posted on emsimcases.com). Conclusion: We describe a national consensus-building process which resulted in a simulation case template endorsed by simulation educators from across Canada. This template has the potential to: 1. Reduce the replication of effort across sites by facilitating the sharing of simulation cases. 2. Enable national collaboration on the development of both simulation cases and curricula. 3. Facilitate multi centre simulation-based research by removing confounders related to the local adoption of an unfamiliar case template. This could improve the rigour and validity of these studies by reducing inter-site variability. 4. Increase the validity of any simulation scenarios developed for use in national high-stakes assessment.
Altered neurocognitive function in schizophrenia could reflect both genetic and illness-specific effects.
Objectives
To use functional magnetic resonance imaging to discriminate between the influences of the genetic risk for schizophrenia and environmental factors on the neural substrate of verbal fluency, a candidate schizophrenia endophenotype using a case control twin design.
Methods
We studied 23 monozygotic twin pairs: 13 pairs discordant for schizophrenia and 10 pairs of healthy volunteer twins. Groups were matched for age, gender, handedness, level of education, parental socio-economic status, and ethnicity. Behavioural performance and regional brain activation during a phonological verbal fluency task were assessed.
Results
Relative to healthy control twins, both patients and their non-psychotic co-twins produced fewer correct responses and showed less activation in the medial temporal region and inferior frontal gyrus. Twins with schizophrenia showed greater activation than both their non-psychotic co-twins and controls in right lateral temporal cortex, reflecting reduced deactivation during word generation while their non-psychotic co-twins showed greater activation in the left temporal cortex.
Conclusions
Both genetic vulnerability to schizophrenia and schizophrenia were associated with impaired verbal fluency performance, reduced engagement of the medial temporal region and dorsal inferior frontal gyrus. Schizophrenia was specifically associated with an additional reduction in deactivation in the right temporal cortex.
Craving in negative emotional situations (negative craving) is commonly associated with relapse and heavy alcohol use. Elevated dynorphin levels were associated with negative emotions, while variations in the OPRK1 and PDYN genes encoding OPRK1 receptor and dynorphins were associated with alcohol dependence.
Objectives
To investigate potential overlap in the genetic factors underlying, negative craving and alcohol dependence.
Aims
Examine the association of the negative craving and genetic variation in the OPRK1 and PDYN genes.
Methods
13 PDYN and 10 OPRK1 Single Nucleotide Polymorphisms (SNPs), including those previously reported to be associated with alcohol dependence were genotyped in 196 alcohol dependent subjects. The raw scores of the negative subscale of Inventory of Drug Taking Situations (IDTS) were utilized as a quantitative measure of negative craving. Logistic regression models were used to test for associations after controlling for age and gender.
Results
Gene-level haplotype testing demonstrated significant association of negative craving with variation in PDYN (p < 0.05) but not OPRK1 gene. The rs2281285 - rs199794 haplotype showed significant association (p = 0.0236) with negative craving, while rs2235749 - rs10485703 haplotype showed marginally significant association (p = 0.055). This replicates previous findings of association between these haplotypes and alcohol dependence. Negative craving was also associated with PDYN rs2281285 variant (p = 0.012) with estimated effect size of 6.95 (SE = 2.75). This new association finding was not significant after correction for multiple testing (p = 0.18).
Conclusions
Our findings support association of PDYN sequence variation with negative craving in alcohol dependent subjects. Future studies should investigate functional mechanisms of this association.
The RemoveDEBRIS mission has been the first mission to successfully demonstrate, in-orbit, a series of technologies that can be used for the active removal of space debris. The mission started late in 2014 and was sponsored by a grant from the EC that saw a consortium led by the Surrey Space Centre to develop the mission, from concept to in-orbit demonstrations, that terminated in March 2019. Technologies for the capture of large space debris, like a net and a harpoon, have been successfully tested together with hardware and software to retrieve data on non-cooperative target debris kinematics from observations carried out with on board cameras. The final demonstration consisted of the deployment of a drag-sail to increase the drag of the satellite to accelerate its demise.
The completion of a laser safety course remains a core surgical curriculum requirement for otolaryngologists training in the UK. This project aimed to develop a comprehensive laser safety course utilising both technical and non-technical skills simulation.
Methods
Otolaryngology trainees and consultants from the West of Scotland Deanery attended a 1-day course comprising lectures, two high-fidelity simulation scenarios and a technical simulation of safe laser use in practice.
Results
The course, and in particular the use of simulation training, received excellent feedback from otolaryngology trainees and consultants who participated. Both simulation scenarios were validated for future use in laser simulation.
Conclusion
The course has been recognised as a laser safety course sufficient for the otolaryngology Certificate of Completion of Training. To the authors’ knowledge, this article represents the first description of using in situ non-technical skills simulation training for teaching laser use in otolaryngology.
Gut cell losses contribute to overall feed efficiency due to the energy requirement for cell replenishment. Intestinal epithelial cells are sloughed into the intestinal lumen as digesta passes through the gastrointestinal tract, where cells are degraded by endonucleases. This leads to fragmented DNA being present in faeces, which may be an indicator of gut cell loss. Therefore, measuring host faecal DNA content could have potential as a non-invasive marker of gut cell loss and result in a novel technique for the assessment of how different feed ingredients impact upon gut health. Faecal calprotectin (CALP) is a marker of intestinal inflammation. This was a pilot study designed to test a methodology for extracting and quantifying DNA from pig faeces, and to assess whether any differences in host faecal DNA and CALP could be detected. An additional aim was to determine whether any differences in the above measures were related to the pig performance response to dietary yeast-enriched protein concentrate (YPC). Newly weaned (∼26.5 days of age) Large White × Landrace × Pietrain piglets (8.37 kg ±1.10, n = 180) were assigned to one of four treatment groups (nine replicates of five pigs), differing in dietary YPC content: 0% (control), 2.5%, 5% and 7.5% (w/w). Pooled faecal samples were collected on days 14 and 28 of the 36-day trial. Deoxyribonucleic acid was extracted and quantitative PCR was used to assess DNA composition. Pig genomic DNA was detected using primers specific for the pig cytochrome b (CYTB) gene, and bacterial DNA was detected using universal 16S primers. A pig CALP ELISA was used to assess gut inflammation. Dietary YPC significantly reduced feed conversion ratio (FCR) from weaning to day 14 (P<0.001), but not from day 14 to day 28 (P = 0.220). Pig faecal CYTB DNA content was significantly (P = 0.008) reduced in YPC-treated pigs, with no effect of time, whereas total faecal bacterial DNA content was unaffected by diet or time (P>0.05). Faecal CALP levels were significantly higher at day 14 compared with day 28, but there was no effect of YPC inclusion and no relationship with FCR. In conclusion, YPC reduced faecal CYTB DNA content and this correlated positively with FCR, but was unrelated to gut inflammation, suggesting that it could be a non-invasive marker of gut cell loss. However, further validation experiments by an independent method are required to verify the origin of pig faecal CYTB DNA as being from sloughed intestinal epithelial cells.
Introduction: Simulation has assumed an integral role in the Canadian healthcare system with applications in quality improvement, systems development, and medical education. High quality simulation-based research (SBR) is required to ensure the effective and efficient use of this tool. This study sought to establish national SBR priorities and describe the barriers and facilitators of SBR in Emergency Medicine (EM) in Canada. Methods: Simulation leads (SLs) from all fourteen Canadian Departments or Divisions of EM associated with an adult FRCP-EM training program were invited to participate in three surveys and a final consensus meeting. The first survey documented active EM SBR projects. Rounds two and three established and ranked priorities for SBR and identified the perceived barriers and facilitators to SBR at each site. Surveys were completed by SLs at each participating institution, and priority research themes were reviewed by senior faculty for broad input and review. Results: Twenty SLs representing all 14 invited institutions participated in all three rounds of the study. 60 active SBR projects were identified, an average of 4.3 per institution (range 0-17). 49 priorities for SBR in Canada were defined and summarized into seven priority research themes. An additional theme was identified by the senior reviewing faculty. 41 barriers and 34 facilitators of SBR were identified and grouped by theme. Fourteen SLs representing 12 institutions attended the consensus meeting and vetted the final list of eight priority research themes for SBR in Canada: simulation in CBME, simulation for interdisciplinary and inter-professional learning, simulation for summative assessment, simulation for continuing professional development, national curricular development, best practices in simulation-based education, simulation-based education outcomes, and simulation as an investigative methodology. Conclusion: Conclusion: This study has summarized the current SBR activity in EM in Canada, as well as its perceived barriers and facilitators. We also provide a consensus on priority research themes in SBR in EM from the perspective of Canadian simulation leaders. This group of SLs has formed a national simulation-based research group which aims to address these identified priorities with multicenter collaborative studies.
Introduction: Capitalizing on the success of Simulation-Based Education (SBE) in residency-training programs, simulation has been gradually integrated into Continued Professional Development (CPD) programs for Emergency Physicians (EPs) in Canada. This study sought to characterize how Canadian academic emergency medicine (EM) departments have implemented SBE for CPD. Methods: We conducted two national surveys: 1) the National Faculty Simulation Status Assessment Survey, administered by telephone to the simulation directors (or equivalent) at 20 Canadian academic EM sites and 2) the Faculty Simulation Needs Assessment Survey administered online to all full-time EPs across 9 Canadian academic EM sites. Results: The response rates for the National Status and Needs Assessment Surveys were 100% (20/20), and 40% (252/635), respectively. The majority (60%) of Canadian academic EM sites reported utilizing SBE for CPD, though only 30% reported dedicated funding support. EPs reported participating in a median of 3 hours per year of SBE (IQR 1-6 hours). Reported incentivization offered in the form of continued medical education credits varied between simulation directors (67%) and EPs (44%). Simulation directors identified several significant barriers to SBE including a lack of faculty time, fear of peer judgment, and faculty inexperience. In contrast, EP-identified barriers included time commitments outside of shift, lack of opportunities, and lack of departmental. The three most common topics of interest for SBE by EPs were performance of rare procedures, pediatric resuscitation, and neonatal resuscitation. Interprofessional involvement in SBE CPD was valued by both simulation directors and EPs, with most EPs (79%) indicating it is useful. Conclusion: Most Canadian EPs and simulation directors recognize the value of SBE for CPD, yet it is only utilized, infrequently, by 67% of Canadian academic EM departments for this purpose. This may be explained, in part, by poor incentivization for participation. Simulation directors and EPs noted different barriers to SBE implementation for CPD suggesting the need for dialogue to improve utilization. As SBE for CPD is incorporated more frequently, and at more sites, content should be guided by local needs assessments with an emphasis on interprofessional participation.
In the past few years, there has been an unprecedented increase in the number of forcibly displaced migrants worldwide, of which a substantial proportion is refugees and asylum seekers. Refugees and asylum seekers may experience high levels of psychological distress, and show high rates of mental health conditions. It is therefore timely and particularly relevant to assess whether current evidence supports the provision of psychosocial interventions for this population. We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) assessing the efficacy and acceptability of psychosocial interventions compared with control conditions (treatment as usual/no treatment, waiting list, psychological placebo) aimed at reducing mental health problems in distressed refugees and asylum seekers.
Methods
We used Cochrane procedures for conducting a systematic review and meta-analysis of RCTs. We searched for published and unpublished RCTs assessing the efficacy and acceptability of psychosocial interventions in adults and children asylum seekers and refugees with psychological distress. Post-traumatic stress disorder (PTSD), depressive and anxiety symptoms at post-intervention were the primary outcomes. Secondary outcomes include: PTSD, depressive and anxiety symptoms at follow-up, functioning, quality of life and dropouts due to any reason.
Results
We included 26 studies with 1959 participants. Meta-analysis of RCTs revealed that psychosocial interventions have a clinically significant beneficial effect on PTSD (standardised mean difference [SMD] = −0.71; 95% confidence interval [CI] −1.01 to −0.41; I2 = 83%; 95% CI 78–88; 20 studies, 1370 participants; moderate quality evidence), depression (SMD = −1.02; 95% CI −1.52 to −0.51; I2 = 89%; 95% CI 82–93; 12 studies, 844 participants; moderate quality evidence) and anxiety outcomes (SMD = −1.05; 95% CI −1.55 to −0.56; I2 = 87%; 95% CI 79–92; 11 studies, 815 participants; moderate quality evidence). This beneficial effect was maintained at 1 month or longer follow-up, which is extremely important for populations exposed to ongoing post-migration stressors. For the other secondary outcomes, we identified a non-significant trend in favour of psychosocial interventions. Most evidence supported interventions based on cognitive behavioural therapies with a trauma-focused component. Limitations of this review include the limited number of studies collected, with a relatively low total number of participants, and the limited available data for positive outcomes like functioning and quality of life.
Conclusions
Considering the epidemiological relevance of psychological distress and mental health conditions in refugees and asylum seekers, and in view of the existing data on the effectiveness of psychosocial interventions, these interventions should be routinely made available as part of the health care of distressed refugees and asylum seekers. Evidence-based guidelines and implementation packages should be developed accordingly.
Introduction: Non-variceal upper gastrointestinal bleeding (NVUGIB) is a common presentation to the emergency department (ED) accounting for significant morbidity, mortality and health care resource usage. In Alberta, a provincial care pathway was recently developed to provide an evidence informed approach to managing patients with an UGIBs in the ED. Pantoprazole infusions are a commonly used treatment despite evidence that suggests they are generally not indicated prior to endoscopy in the ED. The goal of this project was to optimize management of patients with a NVUGIB, in particular reduce pre-endoscopy pantoprazole infusions. Methods: In July 2016, we implemented a multi-faceted intervention to optimize management of ED patients with NVUGIB including 1. de-emphasizing IV pantoprazole infusions in the ED, 2. clinical decision support (CDS) embedded (for endoscopy, disposition and transfusions) within the order set and 3. educating clinicians about the care pathway. We used a pre/post-order set design, analyzing 391 days pre and 189 days post-order set changes. Data was extracted from our fully integrated electronic health records system. The primary outcome was the % of patients receiving IV pantoprazole infusion ordered by an emergency physician (EP) among all patients with NVUGIB. Secondary outcomes included % transfused with hgb >70g/L and whether using the GIB order set impacted management of NVUGIB patients. Results: In the 391 days pre-order set changes, there were 2165 patients included and in the 189 days post-order set changes, there were 901 patients. For baseline characteristics, patients in the post-order set change group were significantly older (64.4 yrs vs 60.9 yrs p-value=0.0016) and had a lower hgb (115 vs 118, p-value=0.049) but otherwise for gender, measures of severity of illness (systolic blood pressure, heart rate, CTAS, % admitted) there were no significantly differences. For the primary outcome, in the pre-order set phase, 47.1% received a pantoprazole infusion ordered by an EP, compared to 31.5% in the post-order phase, for an absolute reduction of 15.6% (p-value= <0.001). For the secondary outcomes, transfusion rates were similar pre/post (22.08% vs 22.75%). Significant inter-site variability exists with respect to the reduction in pantoprazole infusion rates across the four sites (-23.3% to +6.12%). Conclusion: Our interventions resulted in a significant overall reduction in pantoprazole infusions in ED patients with NVUGIB. Reductions in pantoprazole infusions varied significantly across the different sites, future work in our department will explore and address this variability. Keys to the success of this project included engaging clinicians as well as leveraging the SCM order sets as well as the provincial care pathway. Although there were no changes in transfusion rates, it in unclear if this a function of the CDS not being effective or whether these transfusions were clinically indicated.
Coinfection with human immunodeficiency virus (HIV) and viral hepatitis is associated with high morbidity and mortality in the absence of clinical management, making identification of these cases crucial. We examined characteristics of HIV and viral hepatitis coinfections by using surveillance data from 15 US states and two cities. Each jurisdiction used an automated deterministic matching method to link surveillance data for persons with reported acute and chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections, to persons reported with HIV infection. Of the 504 398 persons living with diagnosed HIV infection at the end of 2014, 2.0% were coinfected with HBV and 6.7% were coinfected with HCV. Of the 269 884 persons ever reported with HBV, 5.2% were reported with HIV. Of the 1 093 050 persons ever reported with HCV, 4.3% were reported with HIV. A greater proportion of persons coinfected with HIV and HBV were males and blacks/African Americans, compared with those with HIV monoinfection. Persons who inject drugs represented a greater proportion of those coinfected with HIV and HCV, compared with those with HIV monoinfection. Matching HIV and viral hepatitis surveillance data highlights epidemiological characteristics of persons coinfected and can be used to routinely monitor health status and guide state and national public health interventions.
A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.
Methods
This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.
Results
The P300 amplitude and latency were not associated (regression coef. −0.06, 95% CI −0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10–0.28, p < 0.001). There was no evidence of associations between lateral ventricular volume and the other measures (all p > 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.
Conclusions
The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.
Schizophrenia is a highly heritable disorder, linked to several structural abnormalities of the brain. More specifically, previous findings have suggested that increased gyrification in frontal and temporal regions are implicated in the pathogenesis of schizophrenia.
Methods
The current study included participants at high familial risk of schizophrenia who remained well (n = 31), who developed sub-diagnostic symptoms (n = 28) and who developed schizophrenia (n = 9) as well as healthy controls (HC) (n = 16). We first tested whether individuals at high familial risk of schizophrenia carried an increased burden of trait-associated alleles using polygenic risk score analysis. We then assessed the extent to which polygenic risk was associated with gyral folding in the frontal and temporal lobes.
Results
We found that individuals at high familial risk of schizophrenia who developed schizophrenia carried a significantly greater burden of risk-conferring variants for the disorder compared to those at high risk (HR) who developed sub-diagnostic symptoms or remained well and HC. Furthermore, within the HR cohort, there was a significant and positive association between schizophrenia polygenic risk score and bilateral frontal gyrification.
Conclusions
These results suggest that polygenic risk for schizophrenia impacts upon early neurodevelopment to confer greater gyral folding in adulthood and an increased risk of developing the disorder.
There are several hemispheric-scale satellite-derived snow-cover maps available, but none has been fully validated. For the period 23 October–25 December 2000, we compare snow maps of North America derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and operational snow maps from the U.S. National Oceanic and Atmospheric Administration (NOAA) National Operational Hydrologic Remote Sensing Center (NOHRSC), both of which rely on satellite data from the visible and near-infrared parts of the spectrum; we also compare MODIS maps with Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) passive-microwave snow maps for the same period. The maps derived from visible and near-infrared data are more accurate for mapping snow cover than are the passive-microwave-derived maps, but discrepancies exist as to the location and extent of the snow cover even between operational snow maps. The MODIS snow-cover maps show more snow in each of the 8 day periods than do the NOHRSC maps, in part because MODIS maps the effects of fleeting snowstorms due to its frequent coverage. The large (~30 km) footprint of the SSM/I pixel, and the difficulty in distinguishing wet and shallow snow from wet or snow-free ground, reveal differences up to 5.33 x 106 km2 in the amount of snow mapped using MODIS vs SSM/I data. Algorithms that utilize both visible and passive-microwave data, which would take advantage of the all-weather mapping capability of the passive-microwave data, will be refined following the launch of the Advanced Microwave Scanning Radiometer (AMSR) in the fall of 2001.
In anticipation of the launch of the Earth Observing System (EOS) Terra, and the Aqua spacecraft in 1999 and 2000, respectively, efforts are ongoing to determine errors of satellite-derived snow-cover maps. EOS Moderate Resolution Imaging Spectrora-diometer (MODIS) and Advanced Microwave Scanning Radiometer-E (AMSR-E) snow-cover products will be produced. For this study we compare snow maps covering the same study areas in Canada and the United States, acquired from different sensors using different snow-mapping algorithms. Four locations are studied: (1) Saskatchewan, Canada; (2) New England (New Hampshire, Vermont and Massachusetts) and eastern New York; (3) central Idaho and western Montana; and (4) North and South Dakota. Snow maps were produced using a prototype MODIS snow-mapping algorithm from Landsat Thematic Mapper (TM) scenes of each study area at 30 m and when the TM data were degraded to 1 km resolution. U.S. National Operational Hydrologic Remote Sensing Center (NOHRSC) 1km resolution snow maps were also used, as were snow maps derived from 0.5° × 0.5° resolution Special Sensor Microwave Imager (SSM/I) data. A land-cover map derived from the International Geosphere-Biosphere Program land-cover map of North America was also registered to the scenes. The TM, NOHRSC and SSM/ I snow maps, and land-cover maps were compared digitally. In most cases, TM-derived maps show less snow cover than the NOHRSC and SSM/I maps because areas of incomplete snow cover in forests (e.g. tree canopies, branches and trunks) are seen in the TM data but not in the coarser-resolution maps which may map the areas as completely snow-covered. The snow maps generally agree with respect to the spatial variability of the snow cover. The 30 m resolutionTM data provide the most accurate snow maps, and are thus used as the baseline for comparison with the other maps. Results show that the changes in amount of snow cover, as compared to to the 30 m resolution TM maps, are lowest using the TM 1km resolution maps, at 0–40%. The greatest change (>100%) is found in the New England study area, probably due to the presence of patchy snow cover. A scene with patchy snow cover is more difficult to map accurately than is a scene with a well-defined snowline such as is found on the North and South Dakota scene where the changes were 0–40%. There are also some important differences in the amount of snow mapped using the two different SSM/I algorithms because they utilize different channels.