A multinomial quadrivariate D-vine copula mixed model for meta-analysis of diagnostic studies in the presence of non-evaluable subjects

Diagnostic test accuracy studies observe the result of a gold standard procedure that defines the presence or absence of a disease and the result of a diagnostic test. They typically report the number of true positives, false positives, true negatives and false negatives. However, diagnostic test outcomes can also be either non-evaluable positives or non-evaluable negatives. We propose a novel model for the meta-analysis of diagnostic studies in the presence of non-evaluable outcomes, which assumes independent multinomial distributions for the true and non-evaluable positives, and, the true and non-evaluable negatives, conditional on the latent sensitivity, specificity, probability of non-evaluable positives and probability of non-evaluable negatives in each study. For the random effects distribution of the latent proportions, we employ a drawable vine copula that can successively model the dependence in the joint tails. Our methodology is demonstrated with an extensive simulation study and applied to data from diagnostic accuracy studies of coronary computed tomography angiography for the detection of coronary artery disease. The comparison of our method with the existing approaches yields findings in the real data application that change the current conclusions

Does vancomycin prescribing intervention affect vancomycin-resistant enterococcus infection and colonization in hospitals? A systematic review

BACKGROUND: Vancomycin resistant enterococcus (VRE) is a major cause of nosocomial infections in the United States and may be associated with greater morbidity, mortality, and healthcare costs than vancomycin-susceptible enterococcus. Current guidelines for the control of VRE include prudent use of vancomycin. While vancomycin exposure appears to be a risk factor for VRE acquisition in individual patients, the effect of vancomycin usage at the population level is not known. We conducted a systematic review to determine the impact of reducing vancomycin use through prescribing interventions on the prevalence and incidence of VRE colonization and infection in hospitals within the United States. METHODS: To identify relevant studies, we searched three electronic databases, and hand searched selected journals. Thirteen studies from 12 articles met our inclusion criteria. Data were extracted and summarized for study setting, design, patient characteristics, types of intervention(s), and outcome measures. The relative risk, 95% confidence interval, and p-value associated with change in VRE acquisition pre- and post-vancomycin prescription interventions were calculated and compared. Heterogeneity in study results was formally explored by stratified analysis. RESULTS: No randomized clinical trials on this topic were found. Each of the 13 included studies used a quasi-experimental design of low hierarchy. Seven of the 13 studies reported statistically significant reductions in VRE acquisition following interventions, three studies reported no significant change, and three studies reported increases in VRE acquisition, one of which reported statistical significance. Results ranged from a reduction of 82.5% to an increase of 475%. Studies of specific wards, which included sicker patients, were more likely to report positive results than studies of an entire hospital including general inpatients (Fisher's exact test 0.029). The type of intervention, endemicity status, type of study design, and the duration of intervention were not found to significantly modify the results. Among the six studies that implemented vancomycin reduction strategies as the sole intervention, two of six (33%) found a significant reduction in VRE colonization and/or infection. In contrast, among studies implementing additional VRE control measures, five of seven (71%) reported a significant reduction. CONCLUSION: It was not possible to conclusively determine a potential role for vancomycin usage reductions in controlling VRE colonization and infection in hospitals in the United States. The effectiveness of such interventions and their sustainability remains poorly defined because of the heterogeneity and quality of studies. Future research using high-quality study designs and implementing vancomycin as the sole intervention are needed to answer this question

In Search of HPA Axis Dysregulation in Child and Adolescent Depression

Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis in adults with major depressive disorder is among the most consistent and robust biological findings in psychiatry. Given the importance of the adolescent transition to the development and recurrence of depressive phenomena over the lifespan, it is important to have an integrative perspective on research investigating the various components of HPA axis functioning among depressed young people. The present narrative review synthesizes evidence from the following five categories of studies conducted with children and adolescents: (1) those examining the HPA system’s response to the dexamethasone suppression test (DST); (2) those assessing basal HPA axis functioning; (3) those administering corticotropin-releasing hormone (CRH) challenge; (4) those incorporating psychological probes of the HPA axis; and (5) those examining HPA axis functioning in children of depressed mothers. Evidence is generally consistent with models of developmental psychopathology that hypothesize that atypical HPA axis functioning precedes the emergence of clinical levels of depression and that the HPA axis becomes increasingly dysregulated from child to adult manifestations of depression. Multidisciplinary approaches and longitudinal research designs that extend across development are needed to more clearly and usefully elucidate the role of the HPA axis in depression

The impact of regular physical activity on fatigue, depression and quality of life in persons with multiple sclerosis

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to compare fatigue, depression and quality of life scores in persons with multiple sclerosis who do (Exercisers) and do not (Non-exercisers) regularly participate in physical activity.</p> <p>Methods</p> <p>A cross-sectional questionnaire study of 121 patients with MS (age 25–65 yr) living in Queensland, Australia was conducted. Physical activity level, depression, fatigue and quality of life were assessed using the International Physical Activity Questionnaire, Health Status Questionnaire Short Form 36, Becks Depression Inventory and Modified Fatigue Impact Scale.</p> <p>Results</p> <p>52 participants performed at least two 30-min exercise sessions·wk^-1(Exercisers) and 69 did not participate in regular physical activity (Non-exercisers). Exercisers reported favourable fatigue, depression and quality of life scores when compared to Non-exercisers. Significant weak correlations were found between both leisure-time and overall reported physical activity levels and some subscales of the quality of life and fatigue questionnaires. Additionally, some quality of life subscale scores indicated that regular physical activity had a greater benefit in subjects with moderate MS.</p> <p>Conclusion</p> <p>Favourable fatigue, depression and quality of life scores were reported by persons with MS who regularly participated in physical activity, when compared to persons with MS who were classified as Non-exercisers.</p

Care planning for consumers on community treatment orders: an integrative literature review

Background Case management is the established model for care provision in mental health and is delivered within current care philosophies of person-centred and recovery-oriented care. The fact that people with a mental illness may be forced to receive care and treatment in the community poses challenges for clinicians aiming to engage in approaches that promote shared decision-making and self-determination. This review sought to gain an in-depth understanding of stakeholders’ perspectives and experiences of care planning for consumers’ on CTOs. Methods An integrative review method allowed for inclusion of a broad range of studies from diverse empirical sources. Systematic searches were conducted across six databases. Following appraisal, findings from included papers were coded into groups and presented against a framework of case management. Results Forty-eight papers were included in the review. Empirical studies came from seven countries, with the majority reporting on qualitative methods. Many similarities were reported across studies. Positive gains from CTOs were usually associated with the nature of support received, highlighting the importance of the therapeutic relationship in care planning. Key gaps in care planning included a lack of connection between CTO, treatment and consumer goals and lack of implementation of focussed interventions. Conclusions Current case management processes could be better utilised for consumers on CTOs, with exploration of how this could be achieved warranted. Workers need to be sensitive to the ‘control and care’ dynamic in the care planning relationship, with person-centred approaches requiring core and advanced practitioner and communication skills, including empathy and trust

The “conscious pilot”—dendritic synchrony moves through the brain to mediate consciousness

Cognitive brain functions including sensory processing and control of behavior are understood as “neurocomputation” in axonal–dendritic synaptic networks of “integrate-and-fire” neurons. Cognitive neurocomputation with consciousness is accompanied by 30- to 90-Hz gamma synchrony electroencephalography (EEG), and non-conscious neurocomputation is not. Gamma synchrony EEG derives largely from neuronal groups linked by dendritic–dendritic gap junctions, forming transient syncytia (“dendritic webs”) in input/integration layers oriented sideways to axonal–dendritic neurocomputational flow. As gap junctions open and close, a gamma-synchronized dendritic web can rapidly change topology and move through the brain as a spatiotemporal envelope performing collective integration and volitional choices correlating with consciousness. The “conscious pilot” is a metaphorical description for a mobile gamma-synchronized dendritic web as vehicle for a conscious agent/pilot which experiences and assumes control of otherwise non-conscious auto-pilot neurocomputation

Motor primitives in space and time via targeted gain modulation in cortical networks

Motor cortex (M1) exhibits a rich repertoire of activities to support the generation of complex movements. Recent network models capture many qualitative aspects of M1 dynamics, but they can generate only a few distinct movements (all of the same duration). We demonstrate that simple modulation of neuronal input–output gains in recurrent neuronal network models with fixed connectivity can dramatically reorganize neuronal activity and consequently downstream muscle outputs. We show that a relatively small number of modulatory control units provide sufficient flexibility to adjust high-dimensional network activity using a simple reward-based learning rule. Furthermore, novel movements can be assembled from previously-learned primitives and we can separately change movement speed while preserving movement shape. Our results provide a new perspective on the role of modulatory systems in controlling recurrent cortical activity.Our work was supported by grants from the Wellcome Trust (TPV and JPS WT100000, 246 GH 202111/Z/16/Z) and the Engineering and Physical Sciences Research Council (JPS)

Utvärdering av en förändrad produktionsprocess hos en svensk biltillverkare

An evaluation of a changed production process at an automobile plant in Sweden Background: The present study is an evaluation of a changed production process at an automobile plant in Sweden. The production in the car body-sealing department was changed from a lineout to a line system. The physical and psychosocial working conditions and the musculoskeletal health among the workers have been studied before and after the reorganisation. The process of change, of supportive and non-supportive mechanisms in the implementation of the new organisation was also studied. Method: The physical working demands were studied with measurements, observations and questionnaires, and the psychosocial working conditions were studied with questionnaires and group discussions with the workers. The musculoskeletal health of the workers was measured be the frequency of sick leave, visits to the occupational care unit and by self-reported musculoskeletal symptoms. The process of change was mainly studied by using interviews with the workers and the management, and the economic outcome was studied with both quantitative and qualitative data. Results: The reorganisation lead to somewhat better working conditions for the workers, i.e. the physical load on the lower back has decreased and the breaks was more evenly distributed during the day after the reorganisation. However, the workers possibility to influence the work speed and how they perform their works have decreased, which certainly is related to their experience of the work in the new organisation being more physically demanding. Also the possibility to interact socially and to discuss two and two has decreased, something which many workers experienced as negative. Some musculoskeletal symptoms were more frequent after the reorganisation, especially neck and shoulder symptoms among women. The frequency of visits to the occupational care unit also increased, to a similar degree among both women and men. The decreased possibilities to influence the work, together with the work changing to being more repetitive and demanding than before, is probably an important explanatory factor for the increase in musculoskeletal symptoms. Too little time and resources was spent at introducing the new way of work which, among other things, was reflected by the fact that the female workers did not use the regulation facilities at the new work stations fully. The implemented new organisation have not strengthen the workers inclination to actively participate in further changes since the choice of implementation strategy did not involved them, although this had been promised in the early stage of the present reorganisation. The productivity has increased according to the plans, as has the quality of the body sealing. The investment inthe new organisation seem to have been very profitable and the payback time to be much shorter than expected. Discussion: Much of what was planned to be included in the new organisation is still possible to carry through. A work to gain a more even distribution of the work tasks between the workstations, where the workers knowledge and opinion are taken into consideration, have been started. If the newly employed got the possibility to learn more tasks, the work teams could rotate between different work tasks, which would give more variation in the work situation. To include more work tasks, and for the workers to take turn being the representative for the work team is still possible to do. Education in how to use the regulation facilities for individual regulation of the work height at the new work stations are needed for decreasing the frequency of musculoskeletal symptoms among the workers. Key words: Automobile plant, process of change, possiblitities to influence, social support, work postures, physical and psychosocial working conditions, musculoskeletal symtoms.Bakgrund: Denna studie är en utvärdering av en förändrad produktionsprocess på SAAB Automobile i Trollhättan. Produktionen i tätningsavdelningen, dvs. där bilkarosser tätas, lades om från line-out till line-produktion. Den fysiska och psykosociala arbetsmiljön, liksom hälsan i rörelseorganen, har studerats före och efter förändringen. Själva förändringsprocessen, vilka mekanismer som spelar roll för hur genomförandet av förändringen lyckas, har också studerats. Metod: De fysiska kraven i arbetet har kartlagts både med mätningar, observationer och frågeformulär. Den psykosociala arbetsmiljön speglades via frågeformulär och gruppdiskussioner. Hälsotillståndet mättes i form av sjukskrivningsfrekvens, besök hos företagshälsovården och självrapporterade besvär från rörelseorganen. Förändringsprocessen studerades främst med hjälp av intervjuer med operatörer och chefer. Resultat: Förändringen av arbetsplatserna och arbetsorganisationen i tätningshallen har i viss mån lett till en förbättrad arbetsmiljö för operatörerna. Den belastningsergonomiska exponeringen på nacke och på ländryggen har reducerats och pauserna är mera jämt spridda över dagen. Dock har operatörernas möjlighet att påverka arbetstakt och arbetsutformning minskat betydligt, vilket antagligen hänger intimt samman med upplevelsen av att jobbet i den nya tätningshallen är tyngre och mera ansträngande. Möjligheten till socialt umgänge och samtal har förändrats så att förtroliga kontakter och samtal två och två har försvårats, vilket av många har uppfattats som negativt. Vissa besvär från rörelseapparaten var mera vanliga efter omorganisationen, och det är bland kvinnorna som en ökning av besvär i nack- och skulderregionen är särskilt tydlig. Antalet besök hos företagshälsovården på grund av besvär i rörelseapparaten har också ökat, med där var ökningen lika stor bland kvinnor och män. Att påverkansmöjligheterna och stimulansen i arbetet minskat samtidigt som arbetet blivit mera kortcykligt är antagligen en viktig förklarande faktor till de ökade besvären och att arbetet upplevs som mera ansträngande. Alldeles för litet tid och resurser ägnades åt att introducera det nya arbetssättet, vilket bland annat avspeglas i att kvinnorna inte utnyttjar de förbättrade reglermöjligheterna vid de nya arbetsstationerna fullt ut. Den nu genomförda förändringen har inte stärkt operatörernas förändringsbenägenhet eftersom valet av förändringsstrategi inte involverade dem, trots att detta i ett tidigt skede utlovats. Diskussion: Mycket av det som skulle ingå i den nya arbetsorganisationen är fortfarande möjligt att genomföra. En mera rättvis balansering av arbetsuppgifterna, där operatörernas åsikter och kunskaper bättre tas tillvara, har påbörjats. En satsning på upplärning av de nyanställda skulle möjliggöra rotation mellan arbetslagen, vilket skulle ge en mera varierad arbetssituation. Tillförande av arbetsuppgifter till lagen kan också fortfarande göras, liksom att göra verklighet av planerna att turas om att vara lagombud. Utbildning i hur man tar vara på möjligheterna till individuell reglering av arbetshöjden på de nya arbetsstationerna bör genomföras som en åtgärd att minska besvärsförekomsten hos operatörerna