Don’t Calculate Post-hoc Power Using Observed Estimate of Effect Size

Spexin is a biomarker of the process that regulates leptin sensitivity

The rising prevalence of obesity poses a critical threat to global health, prompting an urgent need for a comprehensive understanding of its underlying mechanisms. This study aimed to delve into the relationship between obesity, leptin sensitivity, and gut hormones, focusing on spexin, glucagon-like peptide-1 (GLP-1), and gastric inhibitory polypeptide (GIP). We examined patients undergoing body contouring surgeries to assess how these hormones and leptin interact. Blood samples were collected at three different time points, and hormone levels were analyzed. Our findings indicated that increases in GLP-1 and decreases in GIP correlated with improved leptin sensitivity, indicated by decreased plasma leptin levels and associated with increase in steepness of the plasma leptin-spexin slope. These results suggest that spexin may serve as a biomarker for leptin sensitivity, the latter influenced by gut hormones in obese individuals. The study provides further evidence that the modulation of leptin sensitivity by gut hormones could be key in addressing obesity and its metabolic consequences.

Effect of Coping Strategies on Perceived Stress and Hair Cortisol Levels During the COVID-19 Pandemic According to Sex

The COVID-19 crisis generated subjective and physiological stress, with important interindividual differences. Studies have shown that coping strategies and sex modulate subjective stress, although their effects on stress hormones have been overlooked. In addition, it remains unknown whether sex and coping interact to predict these stress metrics during long-term stressful events. To examine the impact of coping strategies, sex, and their interaction on subjective and physiological indicators of stress during the year following the arrival of the COVID-19 virus. Coping strategies were assessed using the Brief COPE questionnaire in May 2020. Stress symptoms were assessed as a subjective indicator of stress every 3 months (June 2020 to March 2021) with the Perceived Stress Scale questionnaire in 155 participants (49 men). Of these individuals, 111 provided a 6-cm hair sample in June 2020 to estimate cortisol levels as a physiological indicator of stress before and during the first lockdown. A factor analysis identified three clusters of coping strategies: positive-oriented, avoidance-oriented, and social support. For subjective stress, a linear-mixed model showed that women reported more stress than men. Positive-oriented and avoidance-oriented strategies were associated with less and more stress, respectively. An interaction between sex and coping strategies indicated a positive relationship between social support and perceived stress levels in men. However, among men and women who used this strategy infrequently, women reported higher stress levels than men. For physiological stress, a regression revealed that women had greater cortisol secretion in response to the pandemic. These findings suggest that coping and sex modulate subjective stress, whereas sex influences physiological stress.

Longitudinal Improvement in Public Speaking Skills Through Participation in a Resident Public Speaking Curriculum

OBJECTIVE

To promote public speaking skills, a pediatrics residency program developed a longitudinal public speaking curriculum grounded in deliberate practice and reflective practice.

METHODS

Residents delivered annual presentations and received formal feedback. Audience evaluation forms from 2005 to 2017 were included for analysis. The form used five-point scales (5 =best) for specific presentation elements (clarity, eye contact/body language, pace, succinct text, minimally distracting delivery, clear conclusion, appropriate learning objectives, achieving learning objectives, and answering questions) and for overall quality. Longitudinal changes in scores were analyzed with paired t tests.

RESULTS

Overall, 5771 evaluations of 276 presentations given by 97 residents were analyzed. Between post-graduate year (PGY)-1 and PGY-3 presentations, mean overall rating increased from 4.38 to 4.59 (P < .001, d=0.51). The median percentage of five-point scores increased from 50.0% (IQR, 24.3%-65.4%) to 72.5% (IQR, 53.3%-81.2%). Eight of nine specific elements showed significant increases (median effect size 0.55). Residents whose initial presentations ranked in the bottom quartile had larger improvements than residents initially ranked in the top quartile.

CONCLUSIONS

After pediatric residents participated in a public speaking curriculum with targeted objectives, formal feedback, and repeated practice, their public speaking skills improved. Public speaking curricula can and should be adopted more broadly in graduate medical education.

Power to Detect What? Considerations for Planning and Evaluating Sample Size

ACADEMIC ABSTRACT

In the wake of the replication crisis, social and personality psychologists have increased attention to power analysis and the adequacy of sample sizes. In this article, we analyze current controversies in this area, including choosing effect sizes, why and whether power analyses should be conducted on already-collected data, how to mitigate the negative effects of sample size criteria on specific kinds of research, and which power criterion to use. For novel research questions, we advocate that researchers base sample sizes on effects that are likely to be cost-effective for other people to implement (in applied settings) or to study (in basic research settings), given the limitations of interest-based minimums or field-wide effect sizes. We discuss two alternatives to power analysis, precision analysis and sequential analysis, and end with recommendations for improving the practices of researchers, reviewers, and journal editors in social-personality psychology.

PUBLIC ABSTRACT

Recently, social-personality psychology has been criticized for basing some of its conclusions on studies with low numbers of participants. As a result, power analysis, a mathematical way to ensure that a study has enough participants to reliably "detect" a given size of psychological effect, has become popular. This article describes power analysis and discusses some controversies about it, including how researchers should derive assumptions about effect size, and how the requirements of power analysis can be applied without harming research on hard-to-reach and marginalized communities. For novel research questions, we advocate that researchers base sample sizes on effects that are likely to be cost-effective for other people to implement (in applied settings) or to study (in basic research settings). We discuss two alternatives to power analysis, precision analysis and sequential analysis, and end with recommendations for improving the practices of researchers, reviewers, and journal editors in social-personality psychology.

Interaction of family SES with children's genetic propensity for cognitive and noncognitive skills: No evidence of the Scarr-Rowe hypothesis for educational outcomes

This study examines the role of genes and environments in predicting educational outcomes. We test the Scarr-Rowe hypothesis, suggesting that enriched environments enable genetic potential to unfold, and the compensatory advantage hypothesis, proposing that low genetic endowments have less impact on education for children from high socioeconomic status (SES) families. We use a pre-registered design with Netherlands Twin Register data (426 ≤ N individuals ≤ 3875). We build polygenic indexes (PGIs) for cognitive and noncognitive skills to predict seven educational outcomes from childhood to adulthood across three designs (between-family, within-family, and trio) accounting for different confounding sources, totalling 42 analyses. Cognitive PGIs, noncognitive PGIs, and parental education positively predict educational outcomes. Providing partial support for the compensatory hypothesis, 39/42 PGI × SES interactions are negative, with 7 reaching statistical significance under Romano-Wolf and 3 under the more conservative Bonferroni multiple testing corrections (p-value < 0.007). In contrast, the Scarr-Rowe hypothesis lacks empirical support, with just 2 non-significant and 1 significant (not surviving Romano-Wolf) positive interactions. Overall, we emphasise the need for future replication studies in larger samples. Our findings demonstrate the value of merging social-stratification and behavioural-genetic theories to better understand the intricate interplay between genetic factors and social contexts.

Volatility in Expectations While Awaiting Important News

Waiting for important news is uniquely anxiety provoking, and expectations for one's outcome fluctuate throughout the wait. Emotional volatility is typically associated with negative outcomes, but little is known about volatility in expectations. In Study 1, law graduates (N = 248) estimated their chances of passing the bar exam every 2 weeks during the wait for results. Greater volatility in expectations, operationalized as the frequency with which outcome expectations changed during the wait, was associated with greater worry and more negative emotionality throughout the wait. Study 2 partially replicated these findings in a sample of Trump and Biden supporters (N = 444) awaiting the result of the 2020 presidential election. Study 2 also demonstrated a causal link between constrained (vs. volatile) expectations and worry. Our findings have implications for how best to manage one's expectations while awaiting important news, with the goal of minimizing worry and other negative emotions.

Association of epidural analgesia in labor with neurodevelopmental outcomes in premature infants born at <29 weeks of gestational age

OBJECTIVE

To explore associations between epidural administration to mothers in labor with neurodevelopmental outcomes at 3 years corrected age in preterm infants born <29 weeks gestational age.

STUDY DESIGN

Infants born <29 weeks gestational age between 2006 and 2012 were included. Our primary outcome was a composite of death or neurodevelopmental impairment at 3 years corrected age. Infants were divided into those whose mothers did or did not receive epidural analgesia in labor. Univariable and multivariable regression was used for analysis.

RESULTS

There were 548 infants in the no epidural analgesia group and 121 in the epidural analgesia group. The adjusted odds ratio (95%CI) of neurodevelopmental impairment or death in the epidural group was 1.25 (0.82-1.93). Propensity score-matched results were 1.32 (0.79-2.22).

CONCLUSION

Preterm infants born <29 weeks gestational age to mothers who received epidural analgesia during labor were not associated with poor neurodevelopmental outcomes at 3 years corrected age.

Contrasting constructs or continuum? Examining the dimensionality of body appreciation and body dissatisfaction

Individuals experiencing body dissatisfaction have poorer health outcomes in part due to engaging in less physical activity. Body appreciation is protective of health behaviors and proposed to be conceptually different from body dissatisfaction. Two studies evaluated whether body appreciation and dissatisfaction represented two distinct dimensions, and whether body appreciation and dissatisfaction would interact in their effect on activity-related motivation and behavior. Study 1 (n = 313) was prospective and utilized a self-report measure of physical activity whereas Study 2 (n = 123) was prospective and used an objective measure. All hypotheses and analyses were pre-registered. A multiverse approach was taken to demonstrate the robustness of results. In exploratory factor analyses, body appreciation and dissatisfaction did not represent two distinct dimensions of body image as both loaded onto the same factor. This result was largely supported by latent profile analyses, which revealed that participants scored high, moderate, or low on both body satisfaction and appreciation. Additionally, body appreciation did not buffer the negative impact of body dissatisfaction on activity-related motivation and behavior. This study provides the first statistical evaluation of the theoretical proposition that body appreciation and dissatisfaction may be distinct constructs with distinct relationships to outcomes.

Is survival after transanal total mesorectal excision (taTME) worse than that after traditional total mesorectal excision? A retrospective propensity score-adjusted cohort study

PURPOSE

Transanal total mesorectal excision (taTME) was developed to provide better vision during resection of the mesorectum. Conflicting results have shown an increase in local recurrence and shorter survival after taTME. This study compared the outcomes of taTME and abdominal (open, laparoscopic, robotic) total mesorectal excision (abTME).

METHODS

Patients who underwent taTME or abTME for stages I-III rectal cancer and who received an anastomosis were included. A retrospective analysis of a prospectively conducted database was performed. The primary endpoints were overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). Risk factors were adjusted by propensity score matching (PSM). The secondary endpoints were local recurrence rates and combined poor pathological outcomes.

RESULTS

From 2012 to 2020, a total of 189 patients underwent taTME, and 119 underwent abTME; patients were followed up for a mean of 54.7 (SD 24.2) and 78.4 (SD 34.8) months, respectively (p < 0.001). The 5-year survival rates after taTME and abTME were not significantly different after PSM: OS: 78.2% vs. 88.6% (p = 0.073), CSS: 87.4% vs. 92.1% (p = 0.359), and DFS: 69.3% vs. 80.9% (p = 0.104), respectively. No difference in the local recurrence rate was observed (taTME, n = 10 (5.3%); abTME, n = 10 (8.4%); p = 0.280). Combined poor pathological outcomes were more frequent after abTME (n = 36, 34.3%) than after taTME (n = 35, 19.6%) (p = 0.006); this difference was nonsignificant according to multivariate analysis (p = 0.404).

CONCLUSION

taTME seems to be a good treatment option for patients with rectal cancer and is unlikely to significantly affect local recurrence or survival. However, further investigations concerning the latter are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT0496910).

The Role of Spirituality in Anxiety and Psychological Resilience of Hemodialysis Patients in Turkey

Chronic kidney disease (CKD) is a significant health problem that affects millions of people worldwide and its end-stage manifestation requires hemodialysis treatment, which can have a considerable impact on patients' mental health and quality of life. This study aims to examine the relationship between spirituality and anxiety, as well as spirituality and psychological resilience among hemodialysis patients using the iterative weighted least squares method. Participants included 91 hemodialysis patients, consisting of 49 females and 42 males, whose ages ranged from 20 to 82 years, with a mean age of 48 (SD = 14). The data were collected using the Beck Anxiety Inventory, Spirituality Scale, and Brief Psychological Resilience Scale. Results indicated a weak positive relationship between spirituality and psychological resilience (t = 1.35, P = .183) and a moderate negative relationship between spirituality and anxiety (t = -2.84, P = .006). Furthermore, spirituality accounted for a 1% variance in psychological resilience and a 5% of the variance in anxiety. Additionally, patients' education level, gender, and whom they live with were relatively stronger correlates of psychological resilience, while the patient's education level, gender, marital status, whom they live with, presence of another patient at home receiving hemodialysis treatment were strong correlates of anxiety. This study emphasizes the need for comprehensive care that addresses both physical and psychological aspects of CKD management to improve patient outcomes and quality of life.

When asking 'are you stressed?' is not enough: Hair cortisol, subjective stress, and alcohol use during the first year of the pandemic

The onset of the COVID-19 pandemic was accompanied by an increase in alcohol use in a third of the population worldwide. To date, the literature shows that subjective reports of stress predicted increased alcohol use during the early stages of the pandemic. However, no studies have investigated the effect of physiological stress (via the stress hormone cortisol) on alcohol use during the pandemic. This study aimed to identify the predictive value of cortisol and/or subjective stress on alcohol use during the first year of the pandemic. Every three months, between June 2020 and March 2021, 79 healthy adults (19-54 years old) answered online questionnaires assessing alcohol use. In May 2020, participants reported pre-pandemic alcohol use, while in June 2020, participants reported current alcohol use, subjective stress measures, and provided a 6 cm hair sample. The latter allowed us to quantify the cumulative levels of cortisol produced in the three months prior to and following the start of the mandatory lockdown measures in March 2020 in Quebec, Canada. A relative change in hair cortisol was computed to quantify the physiological stress response. While controlling for sex, age, and psychiatric diagnoses, multilevel linear regressions revealed that alcohol use increased only among people with concomitant high subjective stress and elevated hair cortisol concentrations. Moreover, this increased alcohol use remained elevated one year later. This study documents the importance of simultaneously considering stress biomarkers and subjective stress to identify people at risk of increasing their alcohol use during major stressful life events.

Fragility Part I: a guide to understanding statistical power

The aim of this paper is to close the knowledge-to-practice gap around statistical power. We demonstrate how four factors affect power: p value, effect size, sample size, and variance. This article further delves into the advantages and disadvantages of a priori versus post hoc power analyses, though we believe only understanding of the former is essential to addressing the present-day issue of reproducibility in research. Upon reading this paper, physician-scientists should have expanded their arsenal of statistical tools and have the necessary context to understand statistical fragility.

The Clinical Outcomes of Operative Treatment Versus Conservative Treatment for Dancer's Fractures: Protocol for a Retrospective Cohort Study

Background

Fifth metatarsal fractures are one of the most common foot fractures, and 11% to 25% of such fractures are Dancer’s fractures (distal spiral fractures). Conservative therapy while wearing a cast and operative treatment have been used as preferred modes of treatment in the limited literature available. However, we often see healing problems, such as delayed union and nonunion, when Dancer’s fractures are treated nonoperatively, resulting in a need for secondary intervention. In our institution, treatment has changed over the years from predominantly conservative treatment to mostly operative treatment. To investigate whether our hypothesis holds true that primary surgical treatment is beneficial, a retrospective study was designed.

Objective

The objective of the study is to compare differences between outcomes (delayed union and nonunion) of conservative and operative treatments for Dancer’s fractures.

Methods

A retrospective comparative cohort study will be conducted in a level II trauma center (Zaandam Medical Center). Patients who experienced a Dancer’s fracture in the period of 2012 to 2021 will be included and divided into 2 cohorts—the conservative (2012-2015) and operative (2016-2021) treatment cohorts. The primary outcome will be the differences in percentages of delayed union and nonunion between the two groups. The secondary outcomes will be the percentage of primary conservative treatment failure, the need for secondary operative treatment, complications (infection and hardware failure), and functional outcomes. If 118 patients are included in each group, sufficient power is expected to be reached, depending on the age distribution of patients. The percentages of delayed union and nonunion among the two groups will be calculated and statistically compared via chi-square statistics. A logistic regression analysis will be used to investigate possible associations between patient characteristics and failed conservative treatment. A Mann-Whitney U test will be used to compare functional outcomes between groups. An independent, 2-tailed t test will be used to compare mean 12-Item Short Form Survey scores if they are normally distributed, and a Wilcoxon rank sum test will be used if they are nonnormally distributed.

Results

In total, 2134 potentially relevant health insurance codes have been extracted from the hospital’s register. We expect to find a total of 236 Dancer’s fractures in this data set.

Conclusions

Our study has limitations due to it being a single-center study and data collection being performed retrospectively. However, it covers a large time period and may provide the possibility to show treatment outcome differences (delayed union and nonunion, complications, and functional outcomes) in 2 reasonably large cohorts (conservative and operative treatment cohorts), which has not been done before in literature on Dancer’s fractures. If our hypothesis that surgery is beneficial for Dancer’s fractures is proven true by our study, we plan to further corroborate it by conducting a prospective randomized controlled trial.

International Registered Report Identifier (IRRID)

PRR1-10.2196/37171

Determining influence, interaction and causality of contrast and sequence effects in objective structured clinical exams

INTRODUCTION

Differential rater function over time (DRIFT) and contrast effects (examiners' scores biased away from the standard of preceding performances) both challenge the fairness of scoring in objective structured clinical exams (OSCEs). This is important as, under some circumstances, these effects could alter whether some candidates pass or fail assessments. Benefitting from experimental control, this study investigated the causality, operation and interaction of both effects simultaneously for the first time in an OSCE setting.

METHODS

We used secondary analysis of data from an OSCE in which examiners scored embedded videos of student performances interspersed between live students. Embedded video position varied between examiners (early vs. late) whilst the standard of preceding performances naturally varied (previous high or low). We examined linear relationships suggestive of DRIFT and contrast effects in all within-OSCE data before comparing the influence and interaction of 'early' versus 'late' and 'previous high' versus 'previous low' conditions on embedded video scores.

RESULTS

Linear relationships data did not support the presence of DRIFT or contrast effects. Embedded videos were scored higher early (19.9 [19.4-20.5]) versus late (18.6 [18.1-19.1], p < 0.001), but scores did not differ between previous high and previous low conditions. The interaction term was non-significant.

CONCLUSIONS

In this instance, the small DRIFT effect we observed on embedded videos can be causally attributed to examiner behaviour. Contrast effects appear less ubiquitous than some prior research suggests. Possible mediators of these finding include the following: OSCE context, detail of task specification, examiners' cognitive load and the distribution of learners' ability. As the operation of these effects appears to vary across contexts, further research is needed to determine the prevalence and mechanisms of contrast and DRIFT effects, so that assessments may be designed in ways that are likely to avoid their occurrence. Quality assurance should monitor for these contextually variable effects in order to ensure OSCE equivalence.

Believe-in counterfactual thinking and psychological capital

Counterfactual thinking puts a negative reality and better or worse alternative outcomes in the mind simultaneously. The implicit theory of intelligence considers whether individuals believe that intelligence can be promoted by effort or not. Previous studies suggest that counterfactual thinking interacting with the implicit theory of intelligence would evoke a belief in an attainable future or a belief that a certain future could one day be reality, thereby producing positive effects. Three studies examined the hypothesis that belief in an attainable future through counterfactual thinking would predict psychological capital, which is a positive developmental state of individuals. In Study 1 ( N = 62), belief in an attainable future was operationalized by introducing the implicit theory of intelligence and counterfactual thinking. Incremental theorists had higher psychological capital when engaged in counterfactual thinking than controls. In Study 2 ( N = 71), belief in an attainable future was operationalized by introducing the likelihood of the antecedents and of the outcomes, which were conceptualized as how people believe in their counterfactual thinking. Belief in an attainable future predicted psychological capital even after controlling for the influence of future time perspective and present-fatalistic time perspective, two concepts that depict how individuals process time-related information. In Study 3 ( N = 76), we conducted an intervention study. Participants in the experimental group were directed to construct attainable counterfactual thinking for one week. The experimental group had higher psychological capital than the control group. Across three studies, the findings consistently provided primary support for the hypothesis that belief in an attainable future would predict psychological capital.

Reappraisal-but not Suppression-Tendencies Determine Negativity Bias After Laboratory and Real-World Stress Exposure

Higher reactivity to stress exposure is associated with an increased tendency to appraise ambiguous stimuli as negative. However, it remains unknown whether tendencies to use emotion regulation strategies—such as cognitive reappraisal, which involves altering the meaning or relevance of affective stimuli—can shape individual differences regarding how stress affects perceptions of ambiguity. Here, we examined whether increased reappraisal use is one factor that can determine whether stress exposure induces increased negativity bias. In Study 1, healthy participants (n = 43) rated the valence of emotionally ambiguous (surprised) faces before and after an acute stress or control manipulation and reported reappraisal habits. Increased negativity ratings were milder for stressed individuals that reported more habitual reappraisal use. In Study 2 (n = 97), we extended this investigation to real-world perceived stress before and during the COVID-19 pandemic. We found that reappraisal tendency moderates the relationship between perceived stress and increased negativity bias. Collectively, these findings suggest that the propensity to reappraise determines negativity bias when evaluating ambiguity under stress.

Does fetal leptin and adiponectin influence children's lung function and risk of wheeze?

Adipocytokines, which are secreted during fetal development by both mothers and fetuses, may influence fetal lung development, but little human data are available. We used data from the HOME Study to investigate the associations of cord blood adipocytokine concentrations with children's lung forced expiratory volume (FEV1; N = 160) and their risk of wheeze (N = 281). We measured umbilical cord serum adipocytokine concentrations using enzyme-linked immunosorbent assays and FEV1 using a portable spirometer at ages 4 and 5 to calculate the percent predicted FEV1 (%FEV1). Parents completed standardized questionnaires of their child's wheeze symptoms every 6 months from birth to age 5, then again at ages 6 and 8. We used multivariable linear mixed models and modified Poisson regression with generalized estimating equations to estimate associations of adipocytokine concentrations (log2-transformed) with children's %FEV1 and the risk of wheeze, respectively, adjusting for sociodemographic, perinatal, and child factors. Cord serum leptin was not associated with children's %FEV1. Higher cord serum adiponectin concentrations were associated with higher %FEV1 in girls (β = 3.1, 95% confidence interval [CI]: 0.6, 5.6), but not in boys (β = -1.3, 95% CI: -5.9, 3.3) (sex × adiponectin p-value = 0.05). Higher leptin was associated with lower risk of wheeze in girls (RR = 0.74, 95% CI: 0.66, 0.84), but not boys (RR = 0.87, 95% CI: 0.69, 1.11) (sex × leptin p-value = 0.01). In contrast, higher adiponectin concentrations were associated with lower risk of wheeze (RR = 0.84, 95% CI: 0.73, 0.96) in both boys and girls. These data suggest that fetal adipocytokines may impact lung development and function in early childhood. Future studies are needed to confirm these findings and explore the mechanisms underlying these associations.

Guess what? Different source-guessing strategies for old versus new information

The probability-matching account states that learned specific episodic contingencies of item types and source dominate over general schematic expectations in source guessing. However, recent evidence from Bell et al. [(2020). Source attributions for detected new items: Persistent evidence for schematic guessing. Quarterly Journal of Experimental Psychology, 73(9), 1407-1422] suggest that this only applies to source guessing for information that is recognised as belonging to a previously encoded episode. When information was detected as being new, participants persisted in applying schematic knowledge about the sources' profession. This dissociation in source guessing for detected-old and detected-new information may have been fostered by the specific source-monitoring paradigm by Bell et al. (2020) in which sources were a group of individuals in a certain profession rather than fixed persons from that profession for whom episodic contingencies are more likely to persist also for new information. The aim of the present study was to test whether source guessing for detected-old versus detected-new information also dissociates in a more typical source-monitoring task, the doctor-lawyer paradigm, in which one individual doctor and one lawyer present profession-related information. Despite this change in paradigm, source guessing was based on the item-source contingency only for detected-old information, whereas schematic knowledge persisted for detected-new information. The present study thus adds evidence for persistent schema-based source guessing for new information.

Power Analysis for Null Hypothesis Significance Testing

Before conducting a scientific study, a power analysis is performed to determine the sample size required to test an effect within allowable probabilities of Type I error (α) or Type II error (β). The power of a study is related to Type II error by 1-β. Most scientific studies set α=0.05 and power=0.80 as minimums. More conservative study designs will decrease α or increase power, which will require a larger sample size. The third and final parameter required for a power analysis is the effect size (ES). ES is a measure of the strength of the observation in the outcome of interest (ie, the dependent variable). ES must be estimated from pilot studies or published values. A small ES will require a larger sample size than a large ES. It is possible to detect statistically significant findings even for very small ES, if the sample size is sufficiently large. Therefore, it is also essential to evaluate whether ES is sufficiently large to be clinically meaningful.

Influence of Lumbar Mobilizations During the Nordic Hamstring Exercise on Hamstring Measures of Knee Flexor Strength, Failure Point, and Muscle Activity: A Randomized Crossover Trial

OBJECTIVE

The aims of this study were to quantify the effects of spinal mobilization on force production, failure point, and muscle activity of the hamstrings during the Nordic hamstring exercise (NHE), and to explore individual differences in responses.

METHODS

In a replicated randomized crossover trial, 24 asymptomatic, recreationally active men (age [mean ± standard deviation]: 27 ± 6 years; body mass: 82 ± 17 kg; height: 181 ± 8 cm) completed 2 standardized intervention trials (L4/5 zygapophyseal mobilizations) and 2 control trials. The failure point of the NHE was determined with 3D motion capture. Peak force, knee flexor torque, and electromyography (EMG) of the biceps femoris were measured. Data analyses were undertaken to quantify mean intervention response and explore any individual response heterogeneity.

RESULTS

Mean (95% confidence interval) left-limb force was higher in intervention than in control trials by 18.7 (4.6-32) N. Similarly, right-limb force was higher by 22.0 (3.4-40.6) N, left peak torque by 0.14 (0.06-0.22) N • m, and right peak torque by 0.14 (0.05-0.23) N • m/kg. Downward force angle was decreased in intervention vs control trials by 4.1° (0.5°-7.6°) on the side of application. Both peak EMG activity (P = .002), and EMG at the downward force (right; P = .020) increased in the intervention condition by 16.8 (7.1-26.4) and 8.8 (1.5-16.1) mV, respectively. Mean downward acceleration angle changed by only 0.3° (-8.9° to 9.4°) in intervention vs control trials. A clear response heterogeneity was indicated only for right force (Participant × Intervention interaction: P = .044; response heterogeneity standard deviation = 34.5 [5.7-48.4] N). Individual response heterogeneity was small for all other outcomes.

CONCLUSION

After spinal mobilization, immediate changes in bilateral hamstring force production and peak torque occurred during the NHE. The effect on the NHE failure point was unclear. Electromyographic activity increased on the ipsilateral side. Response heterogeneity was generally similar to the random trial-to-trial variability inherent in the measurement of the outcomes.

Parenting, mental health and economic pathways to prevention of violence against children in South Africa

BACKGROUND

Parenting programs based on social learning theory have increasing empirical evidence for reducing violence against children. Trials are primarily from high-income countries and with young children. Globally, we know little about how parenting programs work to reduce violence, with no known studies in low or middle-income countries (LMICs). This study examines mechanisms of change of a non-commercialized parenting program, Parenting for Lifelong Health for Teens, designed with the World Health Organization and UNICEF. A cluster randomized trial showed main effects on parenting and other secondary outcomes. We conducted secondary analysis of trial data to investigate five potential mediators of reduced violence against children: improved parenting, adolescent behaviour, caregiver mental health, alcohol/drug avoidance, and family economic strengthening.

METHODS

The trial was implemented in rural South Africa with 40 sites, n = 552 family dyads (including adolescents aged 10-18 and primary caregivers). Intervention sites (n = 20) received the 14-session parenting program delivered by local community members, including modules on family budgeting and savings. Control sites (n = 20) received a brief informational workshop. Emotional and physical violence against children/adolescents and each potential mediator were reported by adolescents and caregivers at baseline and 9-13 months post-randomisation. Structural equation modelling was used to test simultaneous hypothesized pathways to violence reduction.

RESULTS

Improvements in four pathways mediated reduced violence against children: 1) improved parenting practices, 2) improved caregiver mental health (reduced depression), 3) increased caregiver alcohol/drug avoidance and 4) improved family economic welfare. Improved child behaviour was not a mediator, although it was associated with less violence.

CONCLUSIONS

Simultaneously bolstering a set of family processes can reduce violence. Supporting self-care and positive coping for caregivers may be essential in challenging contexts. In countries with minimal or no economic safety nets, linking social learning parenting programs with economic strengthening skills may bring us closer to ending violence against children.

Exploring approach motivation: Correlating self-report, frontal asymmetry, and performance in the Effort Expenditure for Rewards Task

Frontal EEG asymmetry has been investigated as a physiological metric of approach motivation, with higher left frontal activity (LFA) suggested to reflect approach motivation. However, correlations between LFA and traditional metrics of approach motivation (e.g., scores from the behavioral inhibition system/behavioral approach system [BIS/BAS] survey) are inconsistent. It is also not clear how LFA correlates to approach motivation on an observable, behavioral level. Here, we tested correlations between BIS/BAS scores, LFA, and performance in the Effort Expenditure for Rewards Task (EEfRT). In our sample (n = 49), BIS/BAS results did not correlate to LFA values (resting or task states), and were also unrelated to EEfRT performance variables. We found evidence of significant and distinct correlations between LFA and EEfRT performance. Resting-state LFA positively correlated to effort expenditure on lower utility trials, where reward size and/or probability were suboptimal. Task-onset LFA captured in the first 5 min of the task was related to overall behavioral performance in the EEfRT. High task-onset LFA correlated to high trial completion rates, high-effort trial selection percentages, and overall monetary earnings. One interpretation of these initial findings is that resting-state LFA reflects approach tendencies to expend effort, but that this extends to suboptimal situations, whereas task-state LFA better reflects effortful approach toward high-utility goals. Given the relatively small sample size and the risk of Type I/II errors, we present the study as exploratory and the results as preliminary. However, the findings highlight interesting initial links between LFA and EEfRT performance. The need for larger replication studies is discussed.

Methylene Blue Does Not Improve Vasoplegia After Left Ventricular Assist Device Implantation

BACKGROUND

Vasoplegia is a frequent complication of left ventricular assist device (LVAD) implantation. We investigated the effectiveness of methylene blue (MB) for vasoplegia in LVAD recipients.

METHODS

Twenty-seven patients received MB for vasoplegia after LVAD implantation and met study criteria between March 2015 and May 2018. Propensity score inverse probability weighting identified 41 controls who did not receive MB for post-LVAD vasoplegia. Clinical outcomes were compared between control and MB groups and between patients who received doses during (n = 15) and after surgery (n = 12). Hemodynamics and vasopressor requirements were analyzed using analysis of covariance.

RESULTS

Median total MB dose was 1.9 mg/kg (interquartile range, 1.2-2.2 mg/kg). Methylene blue recipients experienced a transient initial decline in norepinephrine requirement from 141 ng/kg per min (95% confidence interval [CI], 81-201 ng/kg per min) to 117 ng/kg per min (95% CI, 58-176 ng/kg per min; P = .022) and a delayed decline in vasopressin from 4.8 U/h (95% CI, 3.8-5.8 U/h) to 4.0 U/h (95% CI, 2.8-5.1 U/h) (P = .004). In-hospital mortality, postoperative complications, and end-organ dysfunction did not differ from those of controls. There were no observed differences in mean arterial pressure, vasopressor requirements, or outcomes between patients who received doses during or after surgery. Weighted overall mortality in the entire study cohort was 8.8%.

CONCLUSIONS

Although MB may affect vasopressor requirements, clinical outcomes in vasoplegia after LVAD implantation did not improve and were not affected by the timing of administration.

Clinical Outcomes After Anterior Cruciate Ligament Injury: Panther Symposium ACL Injury Clinical Outcomes Consensus Group

A stringent outcome assessment is a key aspect of establishing evidence-based clinical guidelines for anterior cruciate ligament (ACL) injury treatment. To establish a standardized assessment of clinical outcome after ACL treatment, a consensus meeting including a multidisciplinary group of ACL experts was held at the ACL Consensus Meeting Panther Symposium, Pittsburgh, Pennsylvania, USA, in June 2019. The aim was to establish a consensus on what data should be reported when conducting an ACL outcome study, what specific outcome measurements should be used, and at what follow-up time those outcomes should be assessed. The group reached consensus on 9 statements by using a modified Delphi method. In general, outcomes after ACL treatment can be divided into 4 robust categories: early adverse events, patient-reported outcomes (PROs), ACL graft failure/recurrent ligament disruption, and clinical measures of knee function and structure. A comprehensive assessment after ACL treatment should aim to provide a complete overview of the treatment result, optimally including the various aspects of outcome categories. For most research questions, a minimum follow-up of 2 years with an optimal follow-up rate of 80% is necessary to achieve a comprehensive assessment. This should include clinical examination, any sustained reinjuries, validated knee-specific PROs, and health-related quality of life questionnaires. In the midterm to long-term follow-up, the presence of osteoarthritis should be evaluated. This consensus paper provides practical guidelines for how the aforementioned entities of outcomes should be reported and suggests the preferred tools for a reliable and valid assessment of outcome after ACL treatment.

The Impact of Racially Motivated Housing Discrimination on Allostatic Load among Indigenous University Students

Allostatic load (AL) is an aggregate measure of wear and tear on the body due to the chronic activation of the stress response system. The goal of this study was to examine the association between racially motivated housing discrimination (HD) and AL score within a sample of Indigenous university students. Data for this cross-sectional study were collected from Indigenous adults attending university in a small city in western Canada between 2015 and 2017 (N = 104; mean age = 27.8 years). An item adapted from the Experience of Discrimination Scale was to assess racially motivated HD in the past 12 months. AL was measured as a composite of 7 biomarkers assessing neuroendocrine, cardiovascular, metabolic, and immune system function. Bias-corrected and accelerated bootstrapped linear regression models were used to examine associations adjusting for age, income, parenthood, and other situations in which discrimination had been experienced. Indigenous university students who experienced racially motivated HD in the past year (16.8% of the sample) had an average AL score of approximately 4, which was almost double that of their peers who had not. In an adjusted model, racially motivated HD was associated with a 1.5 point increase in AL score. This model explained 35% of the adjusted variance in AL score, of which racially motivated HD explained 24%. These results suggest Indigenous adults who experienced racially motivated HD in the past year had early and more pronounced wear and tear on neuroendocrine, cardiovascular, metabolic, and immune system functioning in young and middle adulthood than Indigenous peers who did not. These findings combine with others to highlight the need for increased efforts to prevent racially motivated HD in urban centers.

Enhancing Statistical Inference in Psychological Research via Prospective and Retrospective Design Analysis

In the past two decades, psychological science has experienced an unprecedented replicability crisis, which has uncovered several issues. Among others, the use and misuse of statistical inference plays a key role in this crisis. Indeed, statistical inference is too often viewed as an isolated procedure limited to the analysis of data that have already been collected. Instead, statistical reasoning is necessary both at the planning stage and when interpreting the results of a research project. Based on these considerations, we build on and further develop an idea proposed by Gelman and Carlin (2014) termed "prospective and retrospective design analysis." Rather than focusing only on the statistical significance of a result and on the classical control of type I and type II errors, a comprehensive design analysis involves reasoning about what can be considered a plausible effect size. Furthermore, it introduces two relevant inferential risks: the exaggeration ratio or Type M error (i.e., the predictable average overestimation of an effect that emerges as statistically significant) and the sign error or Type S error (i.e., the risk that a statistically significant effect is estimated in the wrong direction). Another important aspect of design analysis is that it can be usefully carried out both in the planning phase of a study and for the evaluation of studies that have already been conducted, thus increasing researchers' awareness during all phases of a research project. To illustrate the benefits of a design analysis to the widest possible audience, we use a familiar example in psychology where the researcher is interested in analyzing the differences between two independent groups considering Cohen's d as an effect size measure. We examine the case in which the plausible effect size is formalized as a single value, and we propose a method in which uncertainty concerning the magnitude of the effect is formalized via probability distributions. Through several examples and an application to a real case study, we show that, even though a design analysis requires significant effort, it has the potential to contribute to planning more robust and replicable studies. Finally, future developments in the Bayesian framework are discussed.

Clinical outcomes after anterior cruciate ligament injury: panther symposium ACL injury clinical outcomes consensus group

PURPOSE

A stringent outcome assessment is a key aspect for establishing evidence-based clinical guidelines for anterior cruciate ligament (ACL) injury treatment. The aim of this consensus statement was to establish what data should be reported when conducting an ACL outcome study, what specific outcome measurements should be used and at what follow-up time those outcomes should be assessed.

METHODS

To establish a standardized approach to assessment of clinical outcome after ACL treatment, a consensus meeting including a multidisciplinary group of ACL experts was held at the ACL Consensus Meeting Panther Symposium, Pittsburgh, PA; USA, in June 2019. The group reached consensus on nine statements by using a modified Delphi method.

RESULTS

In general, outcomes after ACL treatment can be divided into four robust categories-early adverse events, patient-reported outcomes, ACL graft failure/recurrent ligament disruption and clinical measures of knee function and structure. A comprehensive assessment following ACL treatment should aim to provide a complete overview of the treatment result, optimally including the various aspects of outcome categories. For most research questions, a minimum follow-up of 2 years with an optimal follow-up rate of 80% is necessary to achieve a comprehensive assessment. This should include clinical examination, any sustained re-injuries, validated knee-specific PROs and Health-Related Quality of Life questionnaires. In the mid- to long-term follow-up, the presence of osteoarthritis should be evaluated.

CONCLUSION

This consensus paper provides practical guidelines for how the aforementioned entities of outcomes should be reported and suggests the preferred tools for a reliable and valid assessment of outcome after ACL treatment.

LEVEL OF EVIDENCE

V.

Research practices and statistical reporting quality in 250 economic psychology master's theses: a meta-research investigation

The replicability of research findings has recently been disputed across multiple scientific disciplines. In constructive reaction, the research culture in psychology is facing fundamental changes, but investigations of research practices that led to these improvements have almost exclusively focused on academic researchers. By contrast, we investigated the statistical reporting quality and selected indicators of questionable research practices (QRPs) in psychology students' master's theses. In a total of 250 theses, we investigated utilization and magnitude of standardized effect sizes, along with statistical power, the consistency and completeness of reported results, and possible indications of p-hacking and further testing. Effect sizes were reported for 36% of focal tests (median r = 0.19), and only a single formal power analysis was reported for sample size determination (median observed power 1 - β = 0.67). Statcheck revealed inconsistent p-values in 18% of cases, while 2% led to decision errors. There were no clear indications of p-hacking or further testing. We discuss our findings in the light of promoting open science standards in teaching and student supervision.

Don’t abandon RCTs in IVF. We don’t even understand them

The conclusion of the Human Fertilisation and Embryology Authority that ‘add-on’ therapies in IVF are not supported by high-quality evidence has prompted new questions regarding the role of the randomized controlled trial (RCT) in evaluating infertility treatments. Critics argue that trials are cumbersome tools that provide irrelevant answers. Instead, they argue that greater emphasis should be placed on large observational databases, which can be analysed using powerful algorithms to determine which treatments work and for whom. Although the validity of these arguments rests upon the sciences of statistics and epidemiology, the discussion to date has largely been conducted without reference to these fields. We aim to remedy this omission, by evaluating the arguments against RCTs in IVF from a primarily methodological perspective. We suggest that, while criticism of the status quo is warranted, a retreat from RCTs is more likely to make things worse for patients and clinicians.

Brain Tumor Surgery is Safe in Octogenarians and Nonagenarians: A Single-Surgeon 741 Patient Series

OBJECTIVES

Elderly patients with surgically accessible brain tumors are often not offered clinically indicated brain tumor surgery (BTS) because of to assumptions of greater risk for perioperative morbidity and mortality. Because brain tumor incidence is highest in the geriatric population, and because the global population is aging, accurate understanding of BTS risk in elderly patients is critical. We aimed to compare safety of BTS in elderly patients with younger counterparts to better understand the risk-benefit profile of BTS for elderly patients.

METHODS

Retrospective cohort study of young (20-29 years), senior (60-79 years), and elderly (80+ years) patients who underwent BTS with a single neurosurgeon. Differences between pre- and postoperative modified Rankin score (ΔmRS), length of hospitalization (LOH), complication rate, and 30-day readmission rates (30DRR) were recorded.

RESULTS

A total of 741 patients (83 elderly, 570 senior, and 88 young) were identified. No significant difference in preoperative mRS between different age groups, χ² = 0.269, P = 0.874. Elderly complication rate was 6.0%, not significantly different from young (4.5%, P = 0.667) or senior (7.2%, P = 0.696) complication rate. Elderly LOH was 1.93 ± SD 0.176 days; not significantly different from young (3.01 ± 0.384 days, P = 0.081) or senior (2.47 ± 0.144 days, P = 0.881). Statistical equivalence testing showed with 95% confidence that there was equivalence in ΔmRS among age groups.

CONCLUSIONS

Elderly patients did not have significantly different ΔmRS, LOH, 30DRR, or complication rates after BTS compared with younger counterparts. Therefore, in healthy patients, advanced age alone should not prevent patients from being offered BTS.