1,121 research outputs found

    Analysis of eye and head coordination in a visual peripheral recognition task

    Get PDF
    Coordinated eye and head movements simultaneously occur to scan the visual world for relevant targets. However, measuring both eye and head movements in experiments allowing natural head movements may be challenging. This paper provides an approach to study eye-head coordination: First, we demonstrate the capabilities and limits of the eye-head tracking system used, and compare it to other technologies. Second, a behavioral task is introduced to invoke eye-head coordination. Third, a method is introduced to reconstruct signal loss in video-based oculography caused by cornea reflection artifacts in order to extend the tracking range. Finally, parameters of eye-head coordination are identified using EHCA (eye-head co-ordination analyzer), a MATLAB software which was developed to analyze eye-head shifts. To demonstrate the capabilities of the approach, a study with 11 healthy subjects was performed to investigate motion behavior. The approach presented here is discussed as an instrument to explore eye-head coordination, which may lead to further insights into attentional and motor symptoms of certain neurological or psychiatric diseases, e.g., schizophrenia

    Assessing treatment effects and publication bias across different specialties in medicine: a meta-epidemiological study

    Full text link
    ObjectivesTo assess the prevalence of statistically significant treatment effects, adverse events and small-study effects (when small studies report more extreme results than large studies) and publication bias (over-reporting of statistically significant results) across medical specialties.DesignLarge meta-epidemiological study of treatment effects from the Cochrane Database of Systematic Reviews.MethodsWe investigated outcomes from 57 162 studies from 1922 to 2019, and overall 98 966 meta-analyses and 5534 large meta-analyses (≥10 studies). Egger’s and Harbord’s tests to detect small-study effects, limit meta-analysis and Copas selection models to bias-adjust effect estimates and generalised linear mixed models were used to analyse one of the largest collections of evidence in medicine.ResultsMedical specialties showed differences in the prevalence of statistically significant results of efficacy and safety outcomes. Treatment effects from primary studies published in high ranking journals were more likely to be statistically significant (OR=1.52; 95% CI 1.32 to 1.75) while randomised controlled trials were less likely to report a statistically significant effect (OR=0.90; 95% CI 0.86 to 0.94). Altogether 19% (95% CI 18% to 20%) of the large meta-analyses showed evidence for small-study effects, but only 3.9% (95% CI 3.4% to 4.4%) showed evidence for publication bias after further assessment of funnel plots. Adjusting treatment effects resulted in overall less evidence for efficacy.ConclusionsThese results suggest that reporting of large treatment effects from small studies may cause greater concern than publication bias. Incentives should be created so that studies of the highest quality become more visible than studies that report more extreme results

    The statistical properties of RCTs and a proposal for shrinkage

    Full text link
    We abstract the concept of a randomized controlled trial as a triple (β,b,s) , where β is the primary efficacy parameter, b the estimate, and s the standard error ( s>0 ). If the parameter β is either a difference of means, a log odds ratio or a log hazard ratio, then it is reasonable to assume that b is unbiased and normally distributed. This then allows us to estimate the joint distribution of the z-value z=b/s and the signal-to-noise ratio SNR=β/s from a sample of pairs (bi,si) . We have collected 23 551 such pairs from the Cochrane database. We note that there are many statistical quantities that depend on (β,b,s) only through the pair (z,SNR) . We start by determining the estimated distribution of the achieved power. In particular, we estimate the median achieved power to be only 13%. We also consider the exaggeration ratio which is the factor by which the magnitude of β is overestimated. We find that if the estimate is just significant at the 5% level, we would expect it to overestimate the true effect by a factor of 1.7. This exaggeration is sometimes referred to as the winner's curse and it is undoubtedly to a considerable extent responsible for disappointing replication results. For this reason, we believe it is important to shrink the unbiased estimator, and we propose a method for doing so. We show that our shrinkage estimator successfully addresses the exaggeration. As an example, we re-analyze the ANDROMEDA-SHOCK trial. Keywords: Cochrane review; achieved power; exaggeration; randomized controlled trial; type M error

    Verbesserungen der virtuellen Arbeitskultur durch Gamification

    Get PDF
    Flexible und ortsunabhängige Arbeitsformen stellen in vielerlei Hinsicht eine Win-win-Situation für Arbeitgeber und Arbeitnehmer dar. Aufgrund der fortschreitenden Globalisierung, dem technischen Fortschritt und der bevorzugten Arbeitsweise der Generation Z nimmt die Nachfrage nach virtuellen Arbeitsformen zu. Zudem trägt auch die Corona-Krise dazu bei, virtuelle Arbeitsformen längerfristig zu etablieren. Jedoch bringt der Wandel von einem traditionellen hin zu einem virtuellen Arbeitsplatz auch neue Herausforderungen und Probleme mit sich. Mangelnder sozialer Austausch im Team sowie fehlende Motivation der Angestellten kann zu verschlechterter Zusammenarbeit und Isolation von einzelnen Teammitgliedern führen. In dieser Bachelorarbeit wird daher untersucht, wie den genannten Herausforderungen mit Hilfe einer Applikation entgegengewirkt werden kann. Es wird eine Applikation umgesetzt, welche einen virtuellen Arbeitsplatz simuliert und Gamification einsetzt. Ziel dieser Arbeit ist es, eine soziale Umgebung für Personen in virtuellen Arbeitsformen zu schaffen, welche das Risiko der Selbstisolation reduziert. Anhand eines Minimum Viable Products und der Anwendung verschiedener Konzepte der Gamification wird untersucht, wie zur Lösung des Problems beigetragen werden kann. Vorgängig erfordert dies eine Erarbeitung der theoretischen Grundlagen, wobei ein Konzept für die Verwendung von Gamification in einer solchen Anwendung erstellt wird. Weiter wird in dieser Arbeit die Planung und Implementation des Frontend-Teils durchgeführt, während zeitgleich die Um-setzung des Backends durch einen anderen Studierenden stattfindet. Zur Validierung des Minimum Viable Products wurde ein Testlauf mit Personen, welche in virtuellen Arbeitsformen beschäftigt sind, durchgeführt. Durch die Verwendung der implementierten Applikation entwickelt sich bei Personen, welche in virtuellen Arbeitsformen beschäftigt sind, ein Gemeinsamkeitsgefühl. Dieses wirkt motivierend und trägt zur sozialen Zugehörigkeit bei. Die Personen fühlen sich weniger isoliert. Zudem wird das Bedürfnis nach sozialem Austausch zwischen den Teammitgliedern gesteigert. Die durch Gamification entstehenden Spieldynamiken wirken auf die Nutzenden motivierend und schaffen ein anspornendes Arbeitsumfeld. Der Einsatz von Gamification ist aber vorhergehend genau zu analysieren, da die verschiedenen Methoden unterschiedlich auf Einzelpersonen und Teams wirken. Mit dem erarbeiteten Minimum Viable Product wurde gezeigt, dass eine Anwendung, welche einen virtuellen Arbeitsplatz simuliert und Gamification einsetzt, dazu beiträgt die Zusammenarbeit in Teams zu verbessern. Die Ergebnisse der Evaluation zeigen zudem, dass durch die Applikation das Risiko der Selbstisolation minimiert wird. Dementsprechend ist die Weiterentwicklung der Anwendung zu verfolgen und weitere Abklärungen durchzuführen, um das quantifizierbare Potential sowie den effektiven Nutzen der Anwendung zu bestimmen

    Strong evidence for age as the single most dominant predictor of medically supervised driving test-mini mental status test outcomes provide only weak but significant moderate additional predictive value

    Full text link
    Background: With age, medical conditions impairing safe driving accumulate. Consequently, the risk of accidents increases. To mitigate this risk, Swiss law requires biannual assessments of the fitness to drive of elderly drivers. Drivers may prove their cognitive and physical capacity for safe driving in a medically supervised driving test (MSDT) when borderline cases, as indicated by low performance in a set of four cognitive tests, including e.g. the mini mental status test (MMST). Any prognostic, rather than indicative, relations for MSDT outcomes have neither been confirmed nor falsified so far. In order to avoid use of unsubstantiated rules of thumb, we here evaluate the predictive value for MSDT outcomes of the outcomes of the standard set of four cognitive tests, used in Swiss traffic medicine examinations. Methods: We present descriptive information on age, gender and cognitive pretesting results of all MSDTs recorded in our case database from 2017 to 2019. Based on these retrospective cohort data, we used logistic regression to predict the binary outcome MSDT. An exploratory analysis used all available data (model 1). Based on the Akaike Information Criterion (AIC), we then established a model including variables age and MMST (model 2). To evaluate the predictive value of the four cognitive assessments, model 3 included cognitive test outcomes only. Receiver operating characteristics (ROC) and area under the curve (AUC) allowed evaluating discriminative performance of the three different models using independent validation data. Results: Using N = 188 complete data sets of a total of 225 included cases, AIC identified age (p < 0.0008) and MMST (p = 0.024) as dominating predictors for MSDT outcomes with a median AUC of 0.71 (95%-CI 0.57-0.85) across different training and validation splits, while using the four cognitive test results exclusively yielded a median AUC of 0.55 (95%-CI 0.40-0.71). Conclusions: Our analysis provided strong evidence for age as the single most dominant predictor of MSDT outcomes. Adding MMST provides only weak additional predictive value for MSDT outcomes. Combining the results of four cognitive test used as standard screen in Swiss traffic medicine alone, proved to be of poor predictive value. This highlights the importance of MSDTs for balancing between the mitigation of risks by and the right to drive for the elderly. Keywords: Clock test; Cognitive testing; Elderly drivers; Fitness to drive; Medically supervised driving test; Mini mental status test; Receiver operating characteristics; Traffic medicine; Trail making test

    Rescuers at Risk: Posttraumatic Stress Symptoms Among Police Officers, Fire Fighters, Ambulance Personnel, and Emergency and Psychiatric Nurses.

    Get PDF
    Emergency personnel and rescue workers may be at a risk of posttraumatic stress symptoms (PTSS) due to exposure to trauma and work-related stressors. Though rescuers of different professions are often engaged in the same type of emergency, they have different tasks and responsibilities and receive different training in coping with traumatic events and stress; hence, we speculated that the salience of identified risk factors for PTSS vary across their respective professions. The present cross-sectional survey aimed to identify influencing variables on PTSS, well-being, and suicidal ideation that can act differently across professions of rescue workers and emergency personnel. In this anonymous online study, data from 1,002 rescue workers and emergency personnel in Switzerland, were collected: 499 police officers, 239 firefighters, 97 ambulance personnel, and 85 emergency and 82 psychiatric nurses. PTSS, coping strategies, well-being, suicidal ideation, previously experienced and work-related trauma, and self-efficacy were measured and analyzed using multiple regression and structural equation modeling (SEM). The prevalence of suspected posttraumatic stress disorder varied across the professions, ranged from 8% (firefighters) to 22% (psychiatric nurses), and was associated with psychological strain and suicidal ideation. The SEM showed that dysfunctional coping strategies, self-efficacy, previously experienced and work-related trauma, years on job, and female sex explained up to 78% of PTSS and that PTSS itself explained up to 68% of the psychological strain experienced in the different professions. Independent of the profession, dysfunctional coping such as alcohol use, avoidance, and distraction, as well as work-related trauma were the most robust predictors of PTSS. However, while self-efficacy was a risk factor for police officers, firefighters and ambulance personnel, it was a protective factor for emergency and psychiatric nurses. Furthermore, female sex was only a risk factor for ambulance personnel and emergency nurses. In agreement with prior research, emergency personnel and rescuers exhibited enhanced prevalence of PTSS and suspected PTSD, leading to significant psychological strain and suicidal ideation. However, risk factors varied across the professions. Thus, the development of profession-specific trainings to improve self-efficacy and coping with work-related stressors to reduce PTSS, and enhance quality of life, is needed for individuals in such high-risk professions. Clinical Trial Registration: ClinicalTrials.gov Nr. NCT03842553

    Using an expert survey and user feedback to construct PRECHECK: A checklist to evaluate preprints on COVID-19 and beyond

    Full text link
    Background: The quality of COVID-19 preprints should be considered with great care, as their contents can influence public policy. Efforts to improve preprint quality have mostly focused on introducing quick peer review, but surprisingly little has been done to calibrate the public’s evaluation of preprints and their contents. Purpose: The PRECHECK project aimed to generate a tool to teach and guide scientifically literate non-experts to critically evaluate preprints, on COVID-19 and beyond. Methods: To create a checklist, we applied a 4-step procedure consisting of an initial internal review, an external review by a pool of experts (methodologists, meta-researchers/experts on preprints, journal editors, and science journalists), a final internal review, and an implementation stage. For the external review step, experts rated the relevance of each element of the checklist on five-point Likert scales, and provided written feedback. After each internal review round, we applied the checklist on a set of high-quality preprints from an online list of milestone research works on COVID-19 and low-quality preprints, which were eventually retracted, to verify whether the checklist can discriminate between the two categories. Results: At the external review step, 26 of the 54 contacted experts responded. The final checklist contained 4 elements (Research question, Study type, Transparency and integrity, and Limitations), with ‘superficial’ and ‘deep’ levels for evaluation. When using both levels of evaluation, the checklist was effective at discriminating high- from low-quality preprints. Its usability was confirmed in workshops with our target audience: Bachelors students in Psychology and Medicine, and science journalists. Conclusions: We created a simple, easy-to-use tool for helping scientifically literate non-experts navigate preprints with a critical mind. We believe that our checklist has great potential to help guide decisions about the quality of preprints on COVID-19 in our target audience and that this extends beyond COVID-19
    • …
    corecore