Bias (Epidemiology)

across the dominant and non-dominant hands. second, we looked to establish whether changes in hand proprioception that occur with the trained hand following adaptation also transfer to the untrained hand. We found intermanual motor transfer to the left untrained (non-dominant) hand after subjects trained their right (dominant) hand to reach with translated visual feedback of their hand. Motor transfer from the left trained to the right untrained hand was not observed. Despite finding changes in felt hand position in both trained hands, we did not find similar evidence of proprioceptive recalibration in the right or left untrained hands. taken together, our results suggest that unlike visuomotor adaptation, proprioceptive recalibration does not transfer between hands and is specific only to the arm exposed to the distortion.

Two recent observational studies have demonstrated a doseresponse relationship between acetaminophen use and asthma in adolescents (1) and wheeze in early life (2), respectively. Noncomparability between drug users and nonusers is by no means less relevant in adolescence than in early childhood. Acetaminophen may be selectively used among patients with asthma or its predisposing conditions owing to concerns about Reye's Syndrome and the association of asthma with allergy to aspirin or other nonsteroidal anti-inflammatory drugs (NSAID). In the study by Amberbir and coworkers (2), acetaminophen users at baseline might have asthma or its predisposing conditions because acetaminophen use was significantly associated with fever, cough, and fast breathing (see Table in the online supplement to their article). Reverse causation deserves attention. As asthma is a chronic disease, acetaminophen may be more commonly used among patients with asthma by virtue of co-morbidities and associated physiological response/illness behavior. A study suggests that American children with asthma, hay fever, and frequent ear infections are significantly associated with headache (3). Another study suggests that young people with asthma and headache are more likely to have low back pain (4). Reverse causation is an intrinsic weakness in the cross-sectional study by Beasley and colleagues (1). Notwithstanding a longitudinal design, difficulty in delineating the exact onset time of asthma may render the study by Amberbir and coworkers (2) vulnerable to reverse causation. Unless NSAID are not used among acetaminophen nonusers, any observed association between acetaminophen use and asthma can also be due to a negative association between NSAID use and asthma (1,. This is possible, as NSAID may protect against asthma. It has been suggested that aspirin but not acetaminophen may reduce allergic sensitization by inhibiting COX-2 activity, thereby reducing prostaglandin E2related Th1/Th2 imbalance during resolution of common respiratory viral infection in children (5). Oxidative stress, which may cause acute symptoms and aversion to stimuli, has been offered as a biologically plausible mechanism for the association between acetaminophen use and asthma (1, 2). It may be difficult to determine whether oxidative stress is due to acetaminophen or to viral/bacterial infection. The apparent lack of aversion to acetaminophen suggests that any actual association may be better explained by an indolent and silent mechanism. Patients with asthma and acetaminophen users might differ from corresponding reference groups in many major aspects. A randomized placebo-controlled trial is required to address the above controversy.

Background The aim of this study was to examine the effect of preoperative smoking cessation interventions on postoperative complications and smoking cessation itself. Methods Relevant databases were searched for randomized controlled trials (RCTs) of preoperative smoking cessation interventions. Trial inclusion, risk of bias assessment and data extraction were performed by two authors. Risk ratios for the above outcomes were calculated and pooled effects estimated using the fixed-effect method. Results Eleven RCTs were included containing 1194 patients. Smoking interventions were intensive, medium intensity and less intensive. Follow-up for postoperative complications was 30 days. For smoking cessation it was from the day of surgery to 12 months thereafter. Overall, the interventions significantly reduced the occurrence of complications (pooled risk ratio 0·56 (95 per cent confidence interval 0·41 to 0·78); P < 0·001). Intensive interventions increased smoking cessation rates bo...

Many customers demand population forecasts, particularly for small areas. Although the forecast evaluation literature is extensive, it is dominated by a focus on accuracy. We go beyond accuracy by examining the concept of forecast utility in an evaluation of a sample of 2,709 counties and census tracts. Wefind that forecasters provide “value-added” knowledge for areas experiencing rapid change or areas with relatively large populations. For other areas, reduced value is more common than added value. Our results suggest that new forecasting strategies and methods such as composite modeling may substantially improve forecast utility.

macology, mandatory use of rigorous evidentiary criteria in epidemiology/observation studies claiming causal associations, proper interpretation of statistical versus clinical/ pharmacological significance, appropriate interpretation of meta-analyses, meaningful validation of methods, and a more rational statistical approach to subgroup analyses and genetic association studies.

Critical to the discovery, development and rational use of drugs and vaccines are the foundational principles and proper application of statistics. However, in too many cases, there has been misuse of statistics and/or overemphasis on statistical significance (p < 0.05), as though this criterion possessed truth-guaranteeing properties. To clarify confusion about the proper use of statistics in pharmacology, we summarize briefly the foundational principles of probability; the role of statistics in assessment of causality; the three basic uses of statistical methods, especially those employed in hypothesis testing; and current statistical issues in pharmacological research. We then review and provide examples of the meaning of statistical significance, the consequences of lack of randomization in epidemiology/observation studies, the criteria for measurement instrument validation, the problems with subgroup analyses, the need for multiple comparison statistical methods, and how to ...

Studies on the face validity of DSM-5 Section II categorical personality disorder (PD) symptoms indicate a bias against older adults. To extend these results, this article explores whether categorically and dimensionally scored PD symptoms of DSM-5 Section II, as measured in the Assessment of DSM-IV Personality Disorders (ADP-IV; Schotte & de Doncker, 1994), corroborate potential age bias across younger (aged 18-34), middle-aged (35-59 years), and older adults (aged 60-75). Differential item functioning (DIF) analyses, following a classical test theory approach, showed that 2 of the 79 symptoms were measured differently across 3 age groups when categorically assessed, and 4 when dimensionally measured. Nevertheless, subsequent differential test functioning analyses supported a low aggregated impact of DIF on the dimensional scales, justifying mean-level comparisons across age groups. Generalizability of the results is discussed in light of methodological issues concerning the resear...

Animals return to rewarded locations. An example of this is conditioned place preference (CPP), which is widely used in studies of drug reward. Although CPP is expressed as increased time spent in a previously rewarded location, the behavioral strategy underlying this change is unknown. We continuously monitored rats ( n = 22) in a three-room in-line configuration, before and after morphine conditioning in one end room. Although sequential room visit durations were variable, their probability distribution was exponential, indicating that the processes controlling visit durations can be modeled by instantaneous room exit probabilities. Further analysis of room transitions and computer simulations of probabilistic models revealed that the exploratory bias toward the morphine room is best explained by an increase in the probability of a subset of rapid, direct transitions from the saline- to the morphine-paired room by the central room. This finding sharply delineates and constrains po...

Response‐adaptive randomization procedures are appropriate for clinical trials in which two or more treatments are to be compared, patients arrive sequentially and the response of each patient is recorded before the next patient arrives. However, for those procedures that involve sequential estimation of model parameters, start‐up designs are commonly required in order to provide initial estimates of the parameters. In this paper, a suite of such start‐up designs for two treatments and binary patient responses are considered and compared in terms of the numbers of patients required in order to give meaningful parameters estimates, the number of patients allocated to the better treatment, and the bias in the parameter estimates. It is shown that permuted block designs with blocks of size 4 are to be preferred over a wide range of parameter values. For the case of two treatments, normal responses and selected start‐up procedures, a design incorporating complete randomization followed ...

Background: The quality of nutrition-related systematic reviews (SRs) is an unstudied but important factor affecting their usefulness. Objectives: The objectives were to evaluate the reporting quality of published SRs and to identify areas of improvement. Design: Descriptive and exploratory analyses of the reporting quality (7 nutrition items and 28 SR reporting items) of all Englishlanguage SRs published through July 2007 linking micronutrients and health outcomes in humans were conducted. Factors that may be associated with reporting quality were also evaluated. Results: We identified 141 eligible SRs of 21 micronutrients. Ninety SRs that included only interventional studies met a higher proportion of our reporting criteria (median: 62%; interquartile range: 51%, 72%) than did 31 SRs with only observational studies (median: 53%; interquartile range: 47%, 60%) or 20 SRs with both study designs (median: 47%; interquartile range: 39%, 52%) (P , 0.001). SRs published after consensus reporting standards (since 2003) met a higher proportion of the reporting criteria than did earlier SRs (median: 59% compared with 50%; P ¼ 0.01); however, the reporting of nutrition variables remained unchanged (median: 38% compared with 33%; P ¼ 0.7). The least-reported nutrition criteria were baseline nutrient exposures (28%) and effects of measurement errors from nutrition exposures (24%). Only 58 SRs (41%) used quality scales or checklists to assess the methodologic quality of the primary studies included. Conclusions: The reporting quality of SRs has improved 3 y after publication of SR reporting standards, but the reporting of nutrition variables has not. Improved adherence to consensus methods and reporting standards should improve the utility of nutrition SRs.

The job exposure matrix (JEM) has been employed to assign cumulative exposure to workers in many epidemiological studies. In these studies, where quantitative data are available, all workers with the same job title and duration are usually assigned similar cumulative exposures, expressed in mg m~3 x years. However, if the job is composed of multiple tasks, each with its own specific exposure profile, then assigning all workers within a job the same mean exposure can lead to misclassification of exposure. This variability of exposure within job titles is one of the major weaknesses of JEMs. A method is presented for reducing the variability in the JEM methodology, which has been called the task exposure matrix (TEM). By summing the cumulative exposures of a worker over all the tasks worked within a job title, it is possible to address the variability of exposure within the job title, and reduce possible exposure misclassification. The construction of a TEM is outlined and its application in the context of a study in the primary aluminium industry is described. The TEM was found to assign significantly different cumulative exposures to the majority of workers in the study, compared with the JEM and the degree of difference in cumulative exposure between the JEM and the TEM varied greatly between contaminants.

In these times of danger of severe international conflicts with fear of the use of atomic weapons and accidents in nuclear power plants, radionuclide contamination in terrestrial ecosystems has nowadays reached a dangerous level. One of the most frequent and studied artificial radionuclide is cesium (137-Cs and 134-Cs), which is on the rise in the world. This orally ingested artificial radionuclide is a serious danger that can cause, in humans and animals, through inflammatory, carcinogenic, carcinogenic, necrotic mechanisms, functional deficiency as diabetes mellitus, cancer and congenital anomalies by DNA and mitochondrial damage. The Author reported autoradiographic and scintigraphic studies describing some, little-known, damage to organs of pancreas, salivary glands, colon, ovary and diabetes mellitus, whose incidence rate is gradually rising worldwide. But a controversy on tissues and organs damaged, by Low-Dose Radiations action, is frequently reported in medical literature.

Background: It has been suggested that participant withdrawal from studies can bias estimates. However, this is only possible when withdrawers and nonwithdrawers differ in an important way. We tested the hypothesis that withdrawers are more likely than nonwithdrawers to be avoidant and negatively affected. Methods: A total of 1160 participants with inflammatory bowel disease were recruited at different sites in Switzerland. Their levels of avoidance coping and negative affectivity were rated by means of 2 short baseline questionnaires. One year later, they were sent a longer follow-up questionnaire. The primary outcome was return versus non-return of the follow-up questionnaire within 3 months. After controlling for potential confounders identified in an extensive literature search, we estimated the odds of returning the follow-up questionnaire for 1 standard deviation of avoidance coping and negative affectivity. Results: The odds ratio for 1 standard deviation was 1.03 (95% confidence interval: 0.89-1.18) for avoidance coping and 1.02 (0.89-1.17) for negative affectivity. Conclusions: The odds of returning the questionnaires did not depend on avoidance coping or negative affectivity.

The so-called "atypical" antipsychotics are rapidly becoming the de facto standard pharmacologic treatment of schizophrenia. This article reviews some common psychopharmacologic and psychological issues that may arise after an outpatient with schizophrenia is switched to one of the newer antipsychotics. Important issues to consider in the first few months after switching include assessment of response to the new medication, dealing with subsequent psychological reactions, and management of an unsatisfactory response. Once the response is established, there are other pharmacologic and psychological issues that arise during the next year or two. Pharmacologic issues that emerge later on include the role of long-term combination antipsychotics, management of new side effects, and deciding whether and when to switch again. Some of the long-term psychological issues include changes in self-image that arise from being less visibly ill, sexuality and intimacy concerns, and recove...

This paper discusses the location bias and the spatial resolution in the reconstruction of a single dipole source by various spatial filtering techniques used for neuromagnetic imaging. We first analyze the location bias for several representative adaptive and non-adaptive spatial filters using their resolution kernels. This analysis theoretically validates previously reported empirical findings that standardized low-resolution electromagnetic tomography (sLORETA) has no location bias. We also find that the minimum-variance spatial filter does exhibit bias in the reconstructed location of a single source, but that this bias is eliminated by using the normalized lead field. We then focus on the comparison of sLORETA and the lead-field normalized minimum-variance spatial filter, and analyze the effect of noise on source location bias. We find that the signal-to-noise ratio (SNR) in the measurements determines whether the sLORETA reconstruction has source location bias, while the lead-field normalized minimum-variance spatial filter has no location bias even in the presence of noise. Finally, we compare the spatial resolution for sLORETA and the minimum-variance filter, and show that the minimum-variance filter attains much higher resolution than sLORETA does. The results of these analyses are validated by numerical experiments as well as by reconstructions based on two sets of evoked magnetic responses.

Background: Tracing mail survey responses is useful for the management of reminders but may cause concerns about anonymity among prospective participants. We examined the impact of numbering return envelopes on the participation and the results of a survey on a sensitive topic among hospital staff. Methods: In a survey about regrets associated with providing healthcare conducted among hospital-based doctors and nurses, two randomly drawn subsamples were provided numbered (N = 1100) and non-numbered (N = 500) envelopes for the return of completed questionnaires. Participation, explicit refusals, and item responses were compared. We also conducted a meta-analysis of the effect of questionnaire/envelope numbering on participation in health surveys. Results: The participation rate was lower in the "numbered" group than in the "non-numbered" group (30.3% vs. 35.0%, p = 0.073), the proportion of explicit refusals was higher in the "numbered" group (23.1% vs 17.5%, p = 0.016), and the proportion of those who never returned the questionnaire was similar (46.6% vs 47.5%, p = 0.78). The means of responses differed significantly for 12 of 105 items (11.4%), which did not differ significantly from the expected frequency of type 1 errors, i.e., 5% (permutation test, p = 0.078). The meta-analysis of 7 experimental surveys (including this one) indicated that numbering is associated with a 2.4% decrease in the survey response rate (95% confidence interval 0.3% to 4.4%). Conclusions: Numbered return envelopes may reduce the response rate and increase explicit refusals to participate in a sensitive survey. Reduced participation was confirmed by a meta-analysis of randomized health surveys. There was no strong evidence of bias.

We used administrative and screening data from 2009 to 2010 to determine if Healthy Start (HS), an enhanced prenatal services program, is reaching the most vulnerable African American women in Kent County, Michigan. Women in HS are at higher risk of key predictors of birth outcomes compared with other women. To advance toward evidence-based HS program evaluations in the absence of randomized controlled trials, future studies using comparison groups need to appropriately establish baseline equivalence on a variety of risk factors related to birth outcomes.

The traditional approach to duty in nervous shock cases required more hurdles to be met than in cases of ordinary physical injury. The feminist critique of these cases demonstrated that these hurdles were created by gendered stereotypes and patriarchal reasoning. The High Court's changed requirements in Tame v New South Wales; Annetts v Australian Stations Pty Ltd (2002) 211 CLR 317 raise the question whether the feminist critique has been rendered obsolete. The article considers some of the previous feminist literature and a quantitative analysis of nervous shock cases in order to examine this question. While women continue to be the majority of claimants in this area, the article emphasises that this is less significant than the fact that the way psychiatric harm is regarded is affected by a gendered way of thinking which permeates our society. Noting that the changes to the requirements in Tame; Annetts and other recent cases still do not put psychiatric harm on exactly the same footing as other personal injury cases, and that the legislative changes created by the various Civil Liability Acts emphasise this and in many cases revert to the previous approach, the authors conclude that the feminist critique still has much to offer this area of law.

Background: The reproducibility of measurements on radiographs is influenced by the techniques by which the images as well as the measurements are obtained. Thus, bias resulting from errors in the image and/or image examinations at two points in time may result in wrongful registrations of true biological or pathological changes. The aim of the present study was to propose and evaluate an indirect radiological examination technique, by which bias, when measuring radiographic bone level, could be substantially reduced as compared to the technique using direct mm measurements. Methods: A plugin to ImageJ was designed to reduce bias when measuring bone loss on radiographic images. In human dry mandibles, radiographic images of 20 teeth were obtained parallel with the tooth axis (alpha = 0) and at an angle of 30°deviation. The direct technique of measuring radiographic bone level (RBL) and the indirect, length-adjusted RBL were registered by four researchers in a double blinded fashion. Results: When mean RBL measured at 0°angle was 7.0 mm, the corresponding mean RBL measured at 30°angle was 7.8 mm, signifying an 11.4 % increase (p = 0.032), whereas the mean length-adjusted RBL increased by 0.6 % (p = 0.9). Conclusions: This study showed that the use of the original, direct technique (ImageJ) resulted in markedly biased radiographic bone level at 30°angle, while the proposed indirect length-adjusted technique (ImageJ plugin) did not.

Background Patient experience surveys are increasingly used to gain information about the quality of healthcare. This paper investigates whether patients who respond before and after reminders to a large national survey of inpatient experience differ in systematic ways in how they evaluate the care they received. Methods The English national inpatient survey of 2009 obtained data from just under 70,000 patients. We used ordinal logistic regression to analyse their evaluations of the quality of their care in relation to whether or not they had received a reminder before they responded. Results 33% of patients responded after the first questionnaire, a further 9% after the first reminder, and a further 10% after the second reminder. Evaluations were less positive among people who responded only after a reminder and lower still among those who needed a second reminder. Conclusions Quality improvement efforts depend on having accurate data and negative evaluations of care received in he...

We resolve the negative sign in Maxwells equations by putting it in another context (the negative sign changes to positive). We also write two of Maxwells equations as one equation. We use the 4x3 determinant. The text uses my computation method for a nxm determinant. We develop a formalism using the 4-dimensional curl of the Electromagnetic potential. We use the scalar electric potential appended with the vector magnetic potential into the same vector.

Fat talking has been assumed to be a causal risk factor for body dissatisfaction in a number of prevention programs and body confidence campaigns. The aim of this paper was to assess whether fat talking meets three criteria necessary for causal risk factors, namely whether fat talking is: (a) cross-sectionally associated with body dissatisfaction; (b) prospectively associated with changes in body dissatisfaction; and (c) associated with changes in body dissatisfaction in experimental studies. A systematic literature review was conducted using electronic databases and hand searching of relevant journals. Meta-analyses provided pooled effect size estimates, and meta-regressions were used to determine whether age, gender or risk of bias were effect modifiers of the relationship. Searches revealed 24 studies. There was a significant cross-sectional association (r = 0.297, 95% CI = 0.225-0.349), which differed in strength between age groups and genders. There was a prospective associatio...

In epidemiological studies, the cause-and-effect relationship is commonly measured using the odds ratio (OR), which reflects the odds of an outcome occurring versus not occurring. However, the crude odds ratio is specific to individual strata and does not account for the influence of confounding variables. The Mantel-Haenszel (MH) test, an extension of the chi-square test, estimates the adjusted odds ratio by accounting for such confounders. This study attempts to assess the influence of confounding factors on the risk of chronic lung disease (CLD) among the elderly, using data from the Study on Global AGEing and Adult Health (SAGE), India, Wave 3. Data were collected from individuals aged 50 years and above who reported being diagnosed with hypertension (HT), diabetes (DI), and asthma (AS), considered as possible risk factors for CLD (defined as "ever diagnosed with chronic lung disease"). Tobacco use ("ever smoked or used smokeless tobacco," SMOKE) and alcohol consumption ("ever consumed alcohol," AL) were treated as confounding variables. In addition to the chi-square test, which assesses associations and crude odds ratios, the MH test was applied to estimate adjusted odds ratios and evaluate the magnitude of confounding. Since smoking and alcohol use vary by age and sex, the analysis was stratified by the age group (AGE) and sex (SEX). Analysis revealed that.

When I first started experimenting with and using MS-DOS in 1986, I was confused by the various types of memory available with the then contemporary PCs: expanded, extended, enhanced expanded, etc. I found that I was frequently asked to explain the concepts associated with these terms and, frankly, could not do so. I decided to remedy that situation by researching the subject and acquiring sufficient knowledge to permit me to understand what was happening from a hardware and software standpoint vis a vis the MS-DOS memory environment. When I had accomplished that task, I wrote an article for the Phoenix PC Users Group Newsletter documenting my new found knowledge. The original article was published in 1989.

Versions: There are a Spanish adaptation developed by Pereira and Vargas (2005) for Venezuelans, an English translation carried out by Sanz (2013), and a brief English version developed by Álvaro Sánchez, Carmelo Vázquez and Jutta Joormann for the US population (Sánchez López, 2011, study 3; Sanchez, Vazquez, Marker, LeMoult & Joormann, 2013; A. Sánchez, personal communication, April 12, 2013). This brief English version does not include the anger-hostility subscale and the remaining three subscales are composed by three items (instead of the four items of the original subscales); however, their indices of internal consistency reliability are still appropriate (.88, .92 and .86 for the subscales of happiness, anxiety, sadness-depression, respectively) and their scores are still sensitive to changes in mood induced by mood induction procedures (Sanchez et al., 2013).

To address declining response rates and rising data-collection costs, survey methodologists have devised new techniques for using process data ("paradata") to address nonresponse by altering the survey design dynamically during data collection. We investigate the substantive consequences of responsive survey design-tools that use paradata to improve the representative qualities of surveys and control costs. By improving representation of reluctant respondents, responsive design can change our understanding of the topic being studied. Using the National Survey of Family Growth Cycle 6, we illustrate how responsive survey design can shape both demographic estimates and models of demographic behaviors based on survey data. By juxtaposing measures from regular and responsive data collection phases, we document how special efforts to interview reluctant respondents may affect demographic estimates. Results demonstrate the potential of responsive survey design to change the quality of demographic research based on survey data.

To address declining response rates and rising data-collection costs, survey methodologists have devised new techniques for using process data (“paradata”) to address nonresponse by altering the survey design dynamically during data collection. We investigate the substantive consequences of responsive survey design—tools that use paradata to improve the representative qualities of surveys and control costs. By improving representation of reluctant respondents, responsive design can change our understanding of the topic being studied. Using the National Survey of Family Growth Cycle 6, we illustrate how responsive survey design can shape both demographic estimates and models of demographic behaviors based on survey data. By juxtaposing measures from regular and responsive data collection phases, we document how special efforts to interview reluctant respondents may affect demographic estimates. Results demonstrate the potential of responsive survey design to change the quality of dem...

Propofol is one of the most frequently used medications for inducing and maintaining anesthesia. However, propofol injection causes pain and discomfort in more than 70% of patients. This study was performed to determine the comparative effects of ketamine, sodium-thiopental, and magnesium sulfate on reducing pain at the onset of anesthesia induced by propofol injection. This single-blind randomized clinical trial was conducted on a population of patients, requiring nonemergency surgeries. The sample size was determined as 25 patients per group. The eligible samples were randomly divided into three groups. An 18-gauge intravenous catheter was inserted in the dorsum of the hand for all patients. Three groups received 0.5 ml/kg of ketamine, 30 mg/kg of magnesium sulfate, and 0.5 ml/kg of sodium-thiopental, respectively. Next, 2.5 mg/kg of propofol 2% was administered at a rate of 1 ml/s. The verbal rating scale (VRS) was applied to assess the severity of pain during injection. Accordin...

Lot quality assurance sampling (LQAS) has a long history of applications in industrial quality control. LQAS is frequently used for rapid surveillance in global health settings, with areas classified as poor or acceptable performance based on the binary classification of an indicator. Historically, LQAS surveys have relied on simple random samples from the population; however, implementing two-stage cluster designs for surveillance sampling is often more cost-effective than simple random sampling. By applying survey sampling results to the binary classification procedure, we develop a simple and flexible non-parametric procedure to incorporate clustering effects into the LQAS sample design to appropriately inflate the sample size, accommodating finite numbers of clusters in the population when relevant. We use this framework to then discuss principled selection of survey design parameters in longitudinal surveillance programs. We apply this framework to design surveys to detect rises in malnutrition prevalence in nutrition surveillance programs in Kenya and South Sudan, accounting for clustering within villages. By combining historical information with data from previous surveys, we design surveys to detect spikes in the childhood malnutrition rate.

objectives To assess the bias incurred when curtailment of Lot Quality Assurance Sampling (LQAS) is ignored, to present unbiased estimators, to consider the impact of cluster sampling by simulation and to apply our method to published polio immunization data from Nigeria. methods We present estimators of coverage when using two kinds of curtailed LQAS strategies: semicurtailed and curtailed. We study the proposed estimators with independent and clustered data using three field-tested LQAS designs for assessing polio vaccination coverage, with samples of size 60 and decision rules of 9, 21 and 33, and compare them to biased maximum likelihood estimators. Lastly, we present estimates of polio vaccination coverage from previously published data in 20 local government authorities (LGAs) from five Nigerian states. results Simulations illustrate substantial bias if one ignores the curtailed sampling design. Proposed estimators show no bias. Clustering does not affect the bias of these estimators. Across simulations, standard errors show signs of inflation as clustering increases. Neither sampling strategy nor LQAS design influences estimates of polio vaccination coverage in 20 Nigerian LGAs. When coverage is low, semicurtailed LQAS strategies considerably reduces the sample size required to make a decision. Curtailed LQAS designs further reduce the sample size when coverage is high. conclusions Results presented dispel the misconception that curtailed LQAS data are unsuitable for estimation. These findings augment the utility of LQAS as a tool for monitoring vaccination efforts by demonstrating that unbiased estimation using curtailed designs is not only possible but these designs also reduce the sample size.

Lot quality assurance sampling (LQAS) has a long history of applications in industrial quality control. LQAS is frequently used for rapid surveillance in global health settings, with areas classified as poor or acceptable performance based on the binary classification of an indicator. Historically, LQAS surveys have relied on simple random samples from the population; however, implementing two-stage cluster designs for surveillance sampling is often more cost-effective than simple random sampling. By applying survey sampling results to the binary classification procedure, we develop a simple and flexible non-parametric procedure to incorporate clustering effects into the LQAS sample design to appropriately inflate the sample size, accommodating finite numbers of clusters in the population when relevant. We use this framework to then discuss principled selection of survey design parameters in longitudinal surveillance programs. We apply this framework to design surveys to detect rises in malnutrition prevalence in nutrition surveillance programs in Kenya and South Sudan, accounting for clustering within villages. By combining historical information with data from previous surveys, we design surveys to detect spikes in the childhood malnutrition rate.

The probability of "replication, " p rep , has been proposed as a means of identifying replicable and reliable effects in the psychological sciences. We conduct a basic test of p rep that reveals that it misestimates the true probability of replication, especially for small effects. We show how these general problems with p rep play out in practice, when it is applied to predict the replicability of observed effects over a series of experiments. Our results show that, over any plausible series of experiments, the true probabilities of replication will be very different from those predicted by p rep . We discuss some basic problems in the formulation of p rep that are responsible for its poor performance, and conclude that p rep is not a useful statistic for psychological science.

Determining the prevalence of neuromuscular disorders for the general population is important to identify the scope of burden on society and enable comparisons with other health conditions. This systematic review aims to identify and collate the findings of studies published between 1960 and 2013 on the prevalence of all types of muscular dystrophies. Relevant articles were identified through electronic database searches and manual searches of reference lists. There were 38 articles from across 19 countries that met the inclusion criteria. The total combined prevalence for all muscular dystrophies for studies classified as having a low risk of bias ranged between 19.8 and 25.1 per 100,000 person-years. Myotonic dystrophy (0.5-18.1 per 100,000), Duchenne muscular dystrophy (1.7-4.2) and facioscapulohumeral muscular dystrophy (3.2-4.6 per 100,000) were found to be the most common types of disorder. There was wide variation in study methodology, case ascertainment, and verification pro...

We propose a unified and flexible framework for ensemble learning in the presence of censoring. For right-censored data, we introduce a random forest algorithm and a generic gradient boosting algorithm for the construction of prognostic and diagnostic models. The methodology is utilized for predicting the survival time of patients suffering from acute myeloid leukemia based on clinical and genetic covariates. Furthermore, we compare the diagnostic capabilities of the proposed censored data random forest and boosting methods, applied to the recurrence-free survival time of node-positive breast cancer patients, with previously published findings.

Diagnostic error is increasingly recognized as a major patient safety concern. Efforts to improve diagnosis have largely focused on safety and quality improvement initiatives that patients, providers, and health care organizations can take to improve the diagnostic process and its outcomes. This educational policy brief presents an alternative strategy for improving diagnosis, centered on future healthcare providers, to improve the education and training of clinicians in every health care profession. The hypothesis is that we can improve diagnosis by improving education. A literature search was first conducted to understand the relationship of education and training to diagnosis and diagnostic error in different health care professions. Based on the findings from this search we present the justification for focusing on education and training, recommendations for specific content that should be incorporated to improve diagnosis, and recommendations on educational approaches that shou...

In the current study, we tested whether representations in visual STM (VSTM) can be biased via top–down attentional modulation of visual activity in retinotopically specific locations. We manipulated attention using retrospective cues presented during the retention interval of a VSTM task. Retrospective cues triggered activity in a large-scale network implicated in attentional control and led to retinotopically specific modulation of activity in early visual areas V1–V4. Importantly, shifts of attention during VSTM maintenance were associated with changes in functional connectivity between pFC and retinotopic regions within V4. Our findings provide new insights into top–down control mechanisms that modulate VSTM representations for flexible and goal-directed maintenance of the most relevant memoranda.

Background: Platelet-rich plasma (PRP) has been recently the emerging biological therapy in which a large pool of signals released from platelets producing a biological microenvironment for local and migrating cells for tissue regeneration. A prospective randomized observational study was done to assess the efficacy of autologous PRP injection in lateral epicondylitis of elbow.Methods: A total 100 patients of lateral epicondylitis were selected and treated from December 2015 to November 2017. VAS (visual analogue scale) and PRTEE (patient rated tennis elbow evaluation) scoring were used for clinical and functional assessment at pre-injection, 2nd week, 4th week, 3rd month and 6th month.Results: At the end of 6 months follow-up 61% patients were completely relieved of pain. 34% patients had mild pain that was significantly decreased (p value <0.0001) from mean VAS (75) and mean PRTEE (78.62) to mean VAS (6.05) and mean PRTEE (5.63). 5 patients were lost their 6 months follow-up. T...

Recall bias represents a major threat to the internal validity of studies using self-reported data. It arises with the tendency of subjects to report past events in a manner that is different between the two study groups. This pattern of recall errors can lead to differential misclassification of the related variable among study subjects with a subsequent distortion of measure of association in any direction from the null, depending on the magnitude and direction of the bias. Although recall bias has largely been viewed as a common concern in case-control studies, it also has been documented as an issue in some prospective cohort and randomized controlled trial designs. The aim of this paper is to address recall bias in selective studies employing retrospective and prospective designs and present some key methodological strategies to consider in analytic research using reported data in order to avoid or minimize recall bias.

Background-Occupational cohort studies are often challenged by the Healthy Worker Survivor Effect, which may bias standard methods of analysis. G-estimation of structural failure time models is an approach for reducing this type of bias. Accelerated failure time models have recently been applied in an occupational cohort but cumulative failure time models have not. Methods-We used g-estimation of a cumulative failure time model to assess the effect of working as a long-haul driver on ischaemic heart disease mortality in a cohort of 30,448 males employed in the unionized US trucking industry in 1985. Exposure was defined by job title and based on work records. We also applied g-estimation of an accelerated failure time model as a sensitivity analysis and approximated hazard ratios from both models to compare them. Results-The Risk Ratio (RR) obtained from the cumulative failure time model, comparing the observed risk under no intervention to the risk had nobody ever been exposed as a long-haul driver, was 1.09 (95% CI: 1.02 -1.16). The RR comparing the risk had everyone been exposed as long-haul driver for 8 years to the risk had nobody ever been exposed was 1.20 (95% CI: 1.04 -1.46). After hazard ratio approximations, accelerated failure time model results were similar.

The presentation of brain facts about specific damages is meaningless to patients unless they can begin to understand how the changes in their brains are lived out in everyday experiences and situations" (Varella, 1991 as stated in McInerney and Walker, 2002)

Background. Pharmaceutical industry funding of psychiatric research has increased significantly in recent decades, raising the question of a relationship between pharmaceutical company funding of clinical psychiatric studies and the outcomes of those studies. This study examines this relationship.Method. s of articles from 1992 and 2002 in four peer-reviewed psychiatric journals were examined. Drug outcomes (n=542) for clinical studies were evaluated and then compared across sponsorship source. Outcome raters were blind to source of sponsorship. The percentage of these studies sponsored by drug companies in 2002 v. 1992 was also compared. In a secondary analysis, the contribution of a series of potentially mediating variables to the relationship between sponsorship source and study outcome was assessed via logistic regression.Results. The percentage of studies sponsored by drug companies increased from 25% in 1992 to 57% in 2002. Favorable outcomes were significantly more common in ...

Background-Driving is a complex form of activity involving especially cognitive and psychomotor functions. These functions may be impaired by Parkinson's disease. The relation between Parkinson's disease and driving ability is still obscure and clinicians have to make decisions concerning the driving ability of their patients based on insuYcent information. Until now no studies have compared diVerent methods for evaluating the driving ability of patients with Parkinson's disease. Methods-The driving ability of 20 patients with idiopathic Parkinson's disease and 20 age and sex matched healthy control subjects was evaluated by a neurologist, psychologist, vocational rehabilitation counsellor, and driving instructor using a standard 10 point scale. The patients and controls also evaluated their own driving ability. Cognitive and psychomotor laboratory tests and a structured on road driving test were used for evaluating the subjects' driving ability. Results-The patients with Parkinson's disease performed worse than the controls both in the laboratory tests and in the driving test. There was a high correlation between the laboratory tests and driving test both in the patient group and in the control group. Disease indices were not associated with the driving test. The neurologist overestimated the ability of patients with Parkinson's disease to drive compared with the driving ability evaluated by the structured on road driving test and with the driving related laboratory tests. Patients themselves were not capable of evaluating their own ability reliably. Conclusion-Driving ability is greatly decreased in patients with even mild to moderate Parkinson's disease. The evaluation of patients' driving ability is very diYcult to carry out without psychological and psychomotor tests and/or a driving test.

Pressure support ventilation (PSV) is almost universally employed in the management of actively breathing ventilated patients with acute respiratory failure. In this partial support mode of ventilation, a fixed pressure is applied to the airway opening, and flow delivery is monitored by the ventilator. Inspiration is terminated when measured inspiratory flow falls below a set fraction of the peak flow rate (flow cutoff); the ventilator then cycles to a lower pressure and expiration commences. We used linear and nonlinear mathematical models to investigate the dynamic behavior of pressure support ventilation and confirmed the predicted behavior using a test lung. Our mathematical and laboratory analyses indicate that pressure support ventilation in the setting of airflow obstruction can be accompanied by marked variations in tidal volume and end-expiratory alveolar pressure, even when subject effort is unvarying. Unstable behavior was observed in the simplest plausible linear mathematical model and is an inherent consequence of the underlying dynamics of this mode of ventilation. The mechanism underlying the observed instability is "feed forward" behavior mediated by oscillatory elevation in end-expiratory pressure. In both mathematical and mechanical models, unstable behavior occurred at impedance values and ventilator settings that are clinically realistic.

Background and objectives: Accumulating evidence shows that cognitive bias modification produces immediate changes in attentional bias for, and consumption of, rewarding substances including food. This study examined the longevity of these attentional bias modification effects. Methods: A modified dot probe paradigm was used to determine whether alterations in biased attentional processing of food cues, and subsequent effects on consumption, were maintained at 24-hour and one-week follow-up. One hundred and forty-nine undergraduate women were trained to direct their attention toward ('attend') or away from ('avoid') food cues (i.e., pictures of chocolate). Within each group, half received a single training session, the other half completed 5 weekly training sessions. Results: Attentional bias for chocolate cues increased in the 'attend' group, and decreased in the 'avoid' group immediately post training. Participants in the 'avoid' group also ate disproportionately less of a chocolate food product in a so-called taste test than did those in the 'attend' group. Importantly, the observed re-training effects were maintained 24 hours later and also one week later, but only following multiple training sessions. Limitations: There are a number of limitations that could be addressed in future research: (a) the inclusion of a no-training control group, (b) the inclusion of a suspicion probe to detect awareness of the purpose of the taste test, and (c) the use of different tasks to assess and retrain attentional bias. Conclusions: The results showed sustained effects of attentional re-training on attentional bias and consumption. They further demonstrate the importance of administering multiple retraining sessions in attentional bias modification protocols.