Small Sample Methods for Multilevel Modeling: A Colloquial Elucidation of REML and the Kenward-Roger Correction

Estimated cochlear neural degeneration is associated with loudness hypersensitivity in individuals with normal audiograms

In animal models, cochlear neural degeneration (CND) is associated with excess central gain and hyperacusis, but a compelling link between reduced cochlear neural inputs and heightened loudness perception in humans remains elusive. The present study examined whether greater estimated cochlear neural degeneration (eCND) in human participants with normal hearing thresholds is associated with heightened loudness perception and sound aversion. Results demonstrated that loudness perception was heightened in ears with greater eCND and in subjects who self-report loudness aversion via a hyperacusis questionnaire. These findings suggest that CND may be a potential trigger for loudness hypersensitivity.

Bridging the gap between multilevel modeling and economic methods

Many datasets used in the social sciences have a hierarchical structure, where lower units of aggregation are 'nested' in higher units. In many disciplines, such data are analyzed using multilevel modeling (MLM, also known as hierarchical linear modeling). However, MLM as a framework is relatively unknown in economics. Instead, economists use a range of separate econometric methods, including cluster-robust standard errors, fixed effects models, models with cross-level interactions, and estimated dependent variable models. Relying on an extensive literature review, this paper describes this methodological divide and provides a detailed comparison between MLM and 'economic methods' in their abilities to deal with three methodological challenges inherent in multilevel data ‒ clustering, omitted variables, and coefficients' heterogeneity across groups. We unfold the comparative advantages of these two methodological approaches and provide practical recommendations about which of them should be used, why, and in what settings.

Intravenous iron therapy to treat burn anaemia: A retrospective cohort study

PURPOSE

Intravenous iron is an effective treatment for anaemia in many populations but has not been evaluated in those with burn anaemia. This study aimed to evaluate the efficacy and safety of intravenous iron to manage burn anaemia.

METHODOLOGY

This was a retrospective cohort study of patients admitted to the Royal Brisbane and Women's Hospital with burns to at least 15% total body surface area (TBSA). Data collected from patient records included demographics, treatment details, and outcomes including length of stay, blood transfusions, and serum haemoglobin concentrations. Linear mixed effects regression models were used to assess the effect of treatment with intravenous iron on haemoglobin over time.

RESULTS

Sixty patients met inclusion criteria, with 11 (18%) treated using intravenous iron. Those treated with intravenous iron had higher TBSA burns (median 39% vs 18%, P = 0.0005), more operations (3 vs 1, P = 0.0012), and more blood transfusions (median 8 units vs 0 units, P = 0.0002). One patient (9%) experienced a minor adverse drug reaction from intravenous iron. When examining the change in modelled haemoglobin levels over the first 14 days following the last major operation, the change in the intravenous iron group (11.22 g/L) was 14.56 g/L greater than the change in the group not receiving intravenous iron (-3.34 g/L, P = 0.0282).

CONCLUSION

This exploratory study provides preliminary evidence of benefit and safety of intravenous iron treatment on burn anaemia recovery.

The Maintenance of the U.S. Racial Hierarchy Through Judgments of Multiracial People Based on Proximity to Whiteness

Previous research has argued that a growing multiracial population will blur boundaries between racial groups, reducing racism and improving interracial relations. However, this is unlikely to happen if multiracial groups are judged according to their proximity to Whiteness. We examined how having White ancestry shapes status perceptions of multiracial groups. Studies 1 and 2 showed that multiracial groups with White ancestry (e.g., Black/White) are considered higher status than dual minority multiracial (e.g., Black/Latinx) and monoracial minority (e.g., Black) groups. Study 3 revealed that multiracial groups with White ancestry are perceived as more competent and warmer than monoracial minority and dual minority multiracial groups, leading to higher status perceptions for multiracial groups with White ancestry. Thus, multiracial people, like other racial minorities, may be judged according to White, Eurocentric standards. The results imply that, without anti-racist intervention, the treatment of multiracial people will reinforce, rather than challenge, the existing racial hierarchy.

Self-Regulatory Coping Behaviors and Stress Reactivity: Exploring the Environmental Affordance Model of Health Disparities

Objectives

To explore the relationship between self-regulatory coping behaviors (SRCB) and hypothalamic pituitary adrenal (HPA) stress reactivity.

Methods

Data came from the Richmond Stress and Sugar Study (n=125, median age: 57 years, 46% non-Hispanic White, 48% African American). The relationships between 11 SRCB (“health-harming” [e.g., smoking] and “health-promoting” [e.g., exercising]) with HPA stress reactivity, indicated by salivary cortisol response to the Trier Social Stress Test, was assessed using multi-level modeling.

Results

Health-harming and health-promoting SRCB were positively correlated (+0.33, p<0.001). Several individual behaviors were related to HPA stress reactivity, for example, smoking and meditation were associated with shallower increases in cortisol (smoking: −13.0%, 95%CI: −20.9% to −4.3%; meditation: −14.0%, 95%CI: −22.0% to −5.1%). However, SRCB summary measures were unrelated to stress reactivity.

Discussion

Health-harming and health-promoting SRCB are inter-related. Specific behaviors, rather than groupings as health-harming versus -promoting, are related to HPA stress reactivity.

Co-ordinated multidisciplinary intervention to reduce time to successful extubation for children on mechanical ventilation: the SANDWICH cluster stepped-wedge RCT

BACKGROUND

Daily assessment of patient readiness for liberation from invasive mechanical ventilation can reduce the duration of ventilation. However, there is uncertainty about the effectiveness of this in a paediatric population.

OBJECTIVES

To determine the effect of a ventilation liberation intervention in critically ill children who are anticipated to have a prolonged duration of mechanical ventilation (primary objective) and in all children (secondary objective).

DESIGN

A pragmatic, stepped-wedge, cluster randomised trial with economic and process evaluations.

SETTING

Paediatric intensive care units in the UK.

PARTICIPANTS

Invasively mechanically ventilated children (aged < 16 years).

INTERVENTIONS

The intervention incorporated co-ordinated multidisciplinary care, patient-relevant sedation plans linked to sedation assessment, assessment of ventilation parameters with a higher than usual trigger for undertaking an extubation readiness test and a spontaneous breathing trial on low levels of respiratory support to test extubation readiness. The comparator was usual care. Hospital sites were randomised sequentially to transition from control to intervention and were non-blinded.

MAIN OUTCOME MEASURES

The primary outcome measure was the duration of invasive mechanical ventilation until the first successful extubation. The secondary outcome measures were successful extubation, unplanned extubation and reintubation, post-extubation use of non-invasive ventilation, tracheostomy, post-extubation stridor, adverse events, length of intensive care and hospital stay, mortality and cost per respiratory complication avoided at 28 days.

RESULTS

The trial included 10,495 patient admissions from 18 paediatric intensive care units from 5 February 2018 to 14 October 2019. In children with anticipated prolonged ventilation (n = 8843 admissions: control, n = 4155; intervention, n = 4688), the intervention resulted in a significantly shorter time to successful extubation [cluster and time-adjusted median difference -6.1 hours (interquartile range -8.2 to -5.3 hours); adjusted hazard ratio 1.11, 95% confidence interval 1.02 to 1.20; p = 0.02] and a higher incidence of successful extubation (adjusted relative risk 1.01, 95% confidence interval 1.00 to 1.02; p = 0.03) and unplanned extubation (adjusted relative risk 1.62, 95% confidence interval 1.05 to 2.51; p = 0.03), but not reintubation (adjusted relative risk 1.10, 95% confidence interval 0.89 to 1.36; p = 0.38). In the intervention period, the use of post-extubation non-invasive ventilation was significantly higher (adjusted relative risk 1.22, 95% confidence interval 1.01 to 1.49; p = 0.04), with no evidence of a difference in intensive care length of stay or other harms, but hospital length of stay was longer (adjusted hazard ratio 0.89, 95% confidence interval 0.81 to 0.97; p = 0.01). Findings for all children were broadly similar. The control period was associated with lower, but not statistically significantly lower, total costs (cost difference, mean £929.05, 95% confidence interval -£516.54 to £2374.64) and significantly fewer respiratory complications avoided (mean difference -0.10, 95% confidence interval -0.16 to -0.03).

LIMITATIONS

The unblinded intervention assignment may have resulted in performance or detection bias. It was not possible to determine which components were primarily responsible for the observed effect. Treatment effect in a more homogeneous group remains to be determined.

CONCLUSIONS

The intervention resulted in a statistically significant small reduction in time to first successful extubation; thus, the clinical importance of the effect size is uncertain.

FUTURE WORK

Future work should explore intervention sustainability and effects of the intervention in other paediatric populations.

TRIAL REGISTRATION

This trial is registered as ISRCTN16998143.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 18. See the NIHR Journals Library website for further project information.

Reducing Incidence of Nonpositive Definite Covariance Matrices in Mixed Effect Models

Deciding which random effects to retain is a central decision in mixed effect models. Recent recommendations advise a maximal structure whereby all theoretically relevant random effects are retained. Nonetheless, including many random effects often leads to nonpositive definiteness. A typical remedy is to simplify the random effect structure by removing random effects or associated covariances. However, this practice is known to bias estimates of remaining covariance parameters and compromise fixed effect inferences. Cholesky decompositions frequently are suggested as an alternative and are automatically implemented in some software. Instead of Cholesky decompositions, we describe factor analytic structures as an approach to avoid nonpositive definiteness. This approach is occasionally employed in biosciences like plant breeding, but, ironically, has not been established in behavioral sciences despite the close historical connection with factor analysis in these fields. We discuss how a factor analytic structure facilitates estimation and conduct simulations to compare convergence and performance to simplifying the random effects structure or Cholesky decomposition approaches. Results show a lower rate of nonpositive definiteness with the factor analytic structure than Cholesky decomposition and suggest that factor analytic covariance structure may be useful to combating nonpositive definiteness, especially in models with many random effects.

Conducting and Evaluating Multilevel Studies: Recommendations, Resources, and a Checklist

Multilevel methods allow researchers to investigate relationships that expand across levels (e.g., individuals, teams, and organizations). The popularity of these methods for studying organizational phenomena has increased in recent decades. Methodologists have examined how these methods work under different conditions, providing an empirical base for making sound decisions when using these methods. In this article, we provide recommendations, tools, resources, and a checklist that can be useful for scholars involved in conducting or assessing multilevel studies. The focus of our article is on two-level designs, in which Level-1 entities are neatly nested within Level-2 entities, and top-down effects are estimated. However, some of our recommendations are also applicable to more complex multilevel designs.

Catching Up on Multilevel Modeling

This review focuses on the use of multilevel models in psychology and other social sciences. We target readers who are catching up on current best practices and sources of controversy in the specification of multilevel models. We first describe common use cases for clustered, longitudinal, and cross-classified designs, as well as their combinations. Using examples from both clustered and longitudinal designs, we then address issues of centering for observed predictor variables: its use in creating interpretable fixed and random effects of predictors, its relationship to endogeneity problems (correlations between predictors and model error terms), and its translation into multivariate multilevel models (using latent-centering within multilevel structural equation models). Finally, we describe novel extensions—mixed-effects location–scale models—designed for predicting differential amounts of variability.

Secularism, family ties and loneliness: A multilevel longitudinal study of ten European societies

OBJECTIVES

Mass media suggest rising political and religious concern about secularism-induced decline of the family. Implications for loneliness remain unexamined. The current study filled this gap.

METHODS

Data were from 10 national probability samples in the Survey of Health, Ageing and Retirement in Europe. Multilevel longitudinal models tested linkages of societal secularism with loneliness, their mediation by specific family relationships, and the role of this cultural dimension in weakening associations of family ties with loneliness. Both weighted Maximum Likelihood and unweighted Bayesian analyses were conducted, separately for each gender.

RESULTS

Societal secularism was not positively linked to either gender's loneliness. Associations with family ties were inconsistent, with only men's average partnered status lower in more secular settings. Nor did any positive indirect effects emerge. Moderation results were also inconsistent, with secularism only weakening linkages of some family dimensions with loneliness. Bayesian estimates were generally nonsignificant.

DISCUSSION

Societal secularism may not be a risk factor for loneliness or for weak family ties. Results stand at odds with religious and political rhetoric on secularism-induced decline of the family, and its individual and societal consequences.

The dual mechanisms of cognitive control and their relation to reasoning and the item-position effect

Braver's (2012) dual mechanisms of cognitive control differentiate between proactive control (PMC; i.e. early selection and maintenance of goal-relevant information) and reactive control (RMC; i.e. a late mobilization of attention when required). It has been suggested that higher cognitive capacities (as indicated by reasoning ability as a major characteristic of fluid intelligence) facilitate using the more resource-demanding PMC. We propose the following alternative explanation: engagement in PMC during the completion of reasoning tests leads to better test performance because gained knowledge (i.e. rules learned) during completion of early items is better maintained and transferred to later items. This learning of rules during the completion of a reasoning test results in an item-position effect (IPE) as an additional source of individual differences besides reasoning ability. We investigated this idea in a sample of 210 young adults who completed the AX-Continuous Performance Task (AX-CPT) and the Vienna Matrices Test (VMT). Using fixed-links modeling, we separated an IPE from reasoning ability in the VMT. Based on reaction time (RT) patterns across AX-CPT conditions, we identified three different groups by means of latent-profile analysis. RT patterns indicated engagement in PMC for Group A, mixed PMC and RMC for Group B, and RMC for Group C. With the consideration of the IPE, groups did not differ in their reasoning abilities. However, Group A (engaging in PMC) had a more pronounced IPE than Group C (engaging in RMC). Therefore, we conclude that PMC contributes to a stronger IPE, which in turn leads to higher scores in reasoning tests as measures of fluid intelligence.

Power(ful) myths: misconceptions regarding sample size in quality of life research

PURPOSE

Carefully selecting the sample size for a research study is one of the most fundamental ways to utilize resources in an ethical manner, maximize impact and replicability, and minimize research waste when investigating questions relevant to health-related quality of life (HRQOL). Despite an increased focus on sample size in the methodological literature, the topic has received limited attention in the HRQOL field, and there are still misconceptions that can weaken even well-intentioned sample size planning. This article aims to highlight common misconceptions, provide accessible and non-technical corrections to these misconceptions, and show how HRQOL researchers can benefit from a more nuanced understanding of sample size planning.

METHOD

Misconceptions were identified broadly through examples within the health, psychology, and HRQOL literatures. In examining these misconceptions, study-level (e.g., missing data, multilevel designs, multiple reported outcomes) and field-level (e.g., publication bias, replicability) issues relevant to HRQOL research were considered.

RESULTS

Misconceptions include: (a) researchers should use rules of thumb or the largest sample size possible, (b) sample size planning should always focus on power, (c) planned power = actual power, (d) there is only one level of power per study, and (e) power is only relevant for the individual researcher. Throughout the article, major themes linked to these misconceptions are mapped onto recent HRQOL studies to make the connections more tangible.

CONCLUSION

By clarifying several challenges and misconceptions regarding sample size planning and statistical power, HRQOL researchers will have the tools needed to augment the research literature in effective and meaningful ways.

The Efficacy of a Mindfulness-Based Intervention for College Students Under Extremely Stressful Conditions

Objectives

This study evaluates the effectiveness of a mindfulness-based intervention (MBI), called Koru mindfulness, among college students.

Methods

Undergraduate students (N = 34) participated in a 4-week mindfulness curriculum embedded within a college course, while a control group (N = 35) taking a different course did not. Notably, the intervention coincided with the start of a state-wide lockdown due to the COVID-19 pandemic.

Results

Despite the additional external stress, there was a significant main effect and a significant interaction between the intervention and time for state mindfulness, (the treatment group experienced increased state mindfulness). There was a significant main effect (higher for the control group) on coronavirus worry and a significant interaction between the intervention and time for perceived stress, with the treatment/control group experiencing decreased/increased stress over time. There was also a significant interaction between the intervention and time for sleep problems with the intervention group experiencing declines in sleep problems over time and also being more likely to experience optimal amounts of sleep over time.

Conclusions

The Koru intervention effectively increased state mindfulness, decreased stress, and improved sleep, suggesting that it is robust even under extremely stressful conditions. This study adds to the growing evidence that MBIs can play an important role in addressing rising concerns regarding the mental health of college students.

Beta-adrenergic glaucoma drugs reduce lymphatic clearance from the eye: A sequential photoacoustic imaging study

Our study aims to determine whether the beta-adrenergic system is involved in the regulation of lymphatic drainage from the eye. For this purpose, we assessed the effect of 2 topical beta-adrenergic blockers, timolol and betaxolol, commonly used as glaucoma drugs, on lymphatic clearance of albumin from the aqueous humor to neck lymph nodes. Adult mice were treated with either topical timolol, a non-selective β-blocker, 0.5% (n = 8), or topical betaxolol, a selective β₁-adrenergic blocker, 0.5% (n = 6) twice daily for 14 days and compared to respective control groups (n = 5 and n = 7). Changes in lymphatic clearance from the eye were assessed using a quantitative in vivo photoacoustic imaging approach. In all subjects, right eye and neck lymph nodes were longitudinally assessed by sequential photoacoustic imaging just prior to near-infrared dye injection into the anterior chamber of the eye, and 20 min, 2 and 4 h after injection. Repeat measurements of mean pixel intensities (MPIs) of right eyes and nodes were performed at all timepoints. The areas under the curves (AUC) were calculated and the AUC of the treated-group was compared to that of controls using the Mann-Whitney U test. The slopes of MPI of each region of interest over time were compared using the linear mixed model after adjusting for IOP decrease after treatment and other parameters such as sex and body weight. In the timolol-treated group, right neck nodes showed significant decrease in AUC signal intensity compared with controls (P = 0.003), and significant decrease in slope of MPI compared with controls (P = 0.0025). In the betaxolol-treated group, right neck nodes showed significant decrease in AUC signal intensity compared with controls (P = 0.02), and significant decrease in slope of MPI compared with controls (P = 0.0069). Topical treatment with timolol and betaxolol reduced lymphatic clearance of albumin from the aqueous humor to the neck lymph nodes. This finding may be relevant for the management of secondary glaucomas and inflammatory eye disease in which the clearance of accumulated proteins and antigen from the eye is important to disease recovery and sight protection. This study suggests that the beta-adrenergic system plays a role in the regulation of lymphatic clearance from the eye.

A Pilot Randomized Controlled Trial of the Alliance Project Gatekeeper Training for Suicide Prevention

Gatekeeper trainings are an approach intended to increase help seeking for suicide prevention. However, little is known of gatekeeper training's function in increasing gatekeeper intent to intervene with those in distress. The current study utilized the theory of planned behavior as a guide to predict gatekeeper's intention to intervene over a six-month period in a pilot randomized controlled trial of the Alliance Project gatekeeper training. Results suggested that the Alliance Project, predicted the growth curve of trainees' intention to intervene better than a control training from pretest through six months. Attitudes toward completing gatekeeper behaviors and perceived behavioral control over gatekeeper behaviors approached significance in a less parsimonious model. These findings suggest the Alliance Project produces changes in gatekeeper's intent to intervene through three months' time.

How Many Classes and Students Should Ideally be Sampled When Assessing the Role of Classroom Climate via Student Ratings on a Limited Budget? An Optimal Design Perspective

A central question in educational research is how classroom climate variables, such as teaching quality, goal structures, or interpersonal teacher behavior, are related to critical student outcomes, such as students’ achievement and motivation. Student ratings are frequently used to measure classroom climate. When using student ratings to assess classroom climate, researchers first ask students to rate classroom climate characteristics and then aggregate the ratings on the class level. Multilevel latent variable modeling is then used to determine whether class-mean ratings of classroom climate are predictive of student outcomes and to correct for unreliability so that the relations can be estimated without bias. In this article, we adopt an optimal design perspective on this specific strategy. Specifically, after briefly recapping a prominent model in climate research, we show and explain (a) how statistical power can be maximized by choosing optimal numbers of classes and students per class given a fixed budget for conducting a study and (b) how the budget required to achieve a prespecified level of power can be minimized. Moreover, we present an example from research on teaching quality to illustrate the procedures and to provide guidance to researchers who are interested in studying the role of classroom climate. Also, we present a Shiny App that can be used to help find optimal designs for classroom climate studies. The app can be accessed at https://psychtools.shinyapps.io/optimalDesignsClassroomClimate

Individualized learning potential in stressful times: How to leverage intensive longitudinal data to inform online learning

Societal events - such as natural disasters, political shifts, or economic downturns - are time-varying and impact the learning potential of students in unique ways. These impacts are likely accentuated during the COVID-19 pandemic, which precipitated an abrupt and wholesale transition to online education. Unfortunately, the individual-level consequences of these events are difficult to determine because the extant literature focuses on single-occasion surveys that produce only group-level inferences. To better understand individual-level variability in stress and learning, intensive longitudinal data can be leveraged. The goal of this paper is to illustrate this by discussing three different techniques for the analysis of intensive longitudinal data: (1) regression analyses; (2) multilevel models; and (3) person-specific network models, (e.g., group iterative multiple model estimation; GIMME). For each technique, a brief background in the context of education research is provided, an illustrative analysis is presented using data from college students who completed a 75-day intensive longitudinal study of cognition, somatic symptoms, anxiety, and intellectual interests during the 2016 U.S. Presidential election - a period of heightened sociopolitical stress - and strengths and limitations are considered. The paper ends with recommendations for future research, especially for intensive longitudinal studies of online education during COVID-19.

Electrophysiological Estimates of the Electrode-Neuron Interface Differ Between Younger and Older Listeners With Cochlear Implants

OBJECTIVES

The primary objective of this study was to quantify differences in evoked potential correlates of spiral ganglion neuron (SGN) density between younger and older individuals with cochlear implants (CIs) using the electrically evoked compound action potential (ECAP). In human temporal bone studies and in animal models, SGN density is the lowest in older subjects and in those who experienced long durations of deafness during life. SGN density also varies as a function of age at implantation and hearing loss etiology. Taken together, it is likely that younger listeners who were deafened and implanted during childhood have denser populations of SGNs than older individuals who were deafened and implanted later in life. In animals, ECAP amplitudes, amplitude growth function (AGF) slopes, and their sensitivity to stimulus interphase gap (IPG) are predictive of SGN density. The authors hypothesized that younger listeners who were deafened and implanted as children would demonstrate larger ECAP amplitudes, steeper AGF slopes, and greater IPG sensitivity than older, adult-deafened and implanted listeners.

DESIGN

Data were obtained from 22 implanted ears (18 individuals). Thirteen ears (9 individuals) were deafened and implanted as children (child-implanted group), and nine ears (9 individuals) were deafened and implanted as adults (adult-implanted group). The groups differed significantly on a number of demographic variables that are implicitly related to SGN density: (1) chronological age; (2) age at implantation; and (3) duration of preimplantation hearing loss. ECAP amplitudes, AGF linear slopes, and thresholds were assessed on a subset of electrodes in each ear in response to two IPGs (7 and 30 µsec). Speech recognition was assessed using a medial vowel identification task.

RESULTS

Compared with the adult-implanted listeners, individuals in the child-implanted group demonstrated larger changes in ECAP amplitude when the IPG of the stimulus was increased from 7 to 30 µsec (i.e., greater IPG sensitivity). On average, child-implanted participants also had larger ECAP amplitudes and steeper AGF linear slopes than the adult-implanted participants, irrespective of IPG. IPG sensitivity for AGF linear slope and ECAP threshold did not differ between age groups. Vowel recognition performance was not correlated with any of the ECAP measures assessed in this study.

CONCLUSIONS

The results of this study support the theory that young CI listeners who were deafened and implanted during childhood may have denser neural populations than older listeners who were deafened and implanted as adults. Potential between-group differences in SGN integrity emphasize a need to investigate optimized CI programming parameters for younger and older listeners.

Willing and able? Theory of mind, social motivation, and social competence in middle childhood and early adolescence

This study investigated the links between theory of mind, social motivation, and children's social competence in middle childhood and early adolescence. Two hundred and sixty four children (136 girls, 128 boys) aged between 8 and 13 years (M Age = 10.88 years, SD = 1.45) completed theory-of-mind tests and self-report questionnaires measuring social motivation. Teachers rated children's social competence at school. Teacher-rated social competence was associated with individual differences in both theory of mind and children's motivation to develop and maintain social relationships. Results suggest that while individual differences in social motivation and theory of mind are partially overlapping, both theory of mind ability and social motivation contribute to successful social interaction at school.

Identifying Cochlear Implant Channels With Relatively Poor Electrode-Neuron Interfaces Using the Electrically Evoked Compound Action Potential

OBJECTIVES

The primary objective of this study was to quantify local (within ear) and global (between ear) variation in the cochlear implant (CI) electrode-neuron interface (ENI) using the electrically evoked compound action potential (ECAP). We tested the hypothesis that, within an ear, ECAP measures can be used to identify channels with presumed good and poor ENIs, which may be influenced by a combination of spiral ganglion neuron (SGN) density, electrode position, and cochlear resistivity. We also hypothesized that ECAP responses would reflect age-related differences in the global quality of the ENI between younger and older listeners who theoretically differ in SGN density.

DESIGN

Data were obtained from 18 implanted ears (13 individuals) with Advanced Bionics HiRes 90K devices. Six participants (8 ears) were adolescents or young adults (age range: 14-32 years), and 7 participants (10 ears) were older adults (age range: 54-88 years). In each ear, single-channel auditory detection thresholds were measured on channels 2 through 15 in response to a spatially focused electrode configuration (steered quadrupolar; focusing coefficient = 0.9). ECAP amplitudes, amplitude growth function (AGF) slopes, and thresholds were assessed on a subset of channels in each ear in response to three interphase gaps (0, 7, and 30 µs). ECAP peak amplitudes were assessed on all channels between 2 and 15. AGFs and ECAP thresholds were measured on the two nonadjacent channels with the lowest and highest focused behavioral thresholds in each ear. ECAP responses were compared across low- and high-threshold channels and between younger and older CI listeners.

RESULTS

Channels that were estimated to interface poorly with the auditory nerve (i.e., high-focused-threshold channels) had steeper ECAP AGF slopes, smaller dynamic ranges, and higher ECAP thresholds than channels with low focused thresholds. Younger listeners had steeper ECAP AGF slopes and larger ECAP peak amplitudes than older listeners. Moreover, younger listeners showed greater interphase gap sensitivity for ECAP amplitude than older listeners.

CONCLUSIONS

ECAP responses may be used to quantify both local (within ear) and global (between ear) variation in the quality of the ENI. Results of this study support future investigation into the use of ECAP responses in site-selection CI programming strategies. The present results also support a growing body of evidence suggesting that adolescents and young adults with CIs may have denser populations of functional SGNs relative to older adults. Potential differences in global SGN integrity between younger and older listeners warrant investigation of optimal CI programming interventions based on their divergent hearing histories.

A randomized controlled trial comparing non-steroidal anti-inflammatory and fusion protein inhibitors singly and in combination on the histopathology of bovine respiratory syncytial virus infection

Bovine respiratory syncytial virus (RSV) has substantial morbidity in young calves, and closely parallels human RSV in infants. We performed a randomized controlled trial in five to six-week-old Holstein calves (Bos taurus). comparing fusion protein inhibitor (FPI) and non-steroidal anti-inflammatory drug (NSAID) singly and in combination at three and five days after experimental BRSV infection. Thirty-six calves received one of six treatments; Ibuprofen started on day 3, Ibuprofen started on day 5, FPI started on day 5, FPI and Ibuprofen started on day 3, FPI and Ibuprofen started on day 5, or placebo. We have previously reported significant clinical benefits when combined FPI and NSAID treatment was started at three and five days after bovine RSV infection. Necropsy was performed on Day 10 following infection and hematoxylin and eosin staining was performed on sections from each lobe. Histology was described using a four-point scale. We performed canonical discrimination analysis (CDA) to determine the structural level where differences between treatments occurred and mixed effects regression to estimate effect sizes. Separation from placebo was maximal for dual therapy at the levels of the alveolus, septum, and bronchus in CDA. We found that the clinical benefits of combined FPI and NSAID treatment of BRSV extend at least partially from histopathological changes in the lung when treatment was started three days after infection. We found decreased lung injury when ibuprofen was started as monotherapy on day 3, but not day 5 following infection. Combined therapy with both an FPI and ibuprofen was always better than ibuprofen alone. We did not prove that the clinical benefits seen starting FPI and ibuprofen five days after infection can be solely explained by histopathological differences as identified on H&E staining.

Personalities in sync: The covariation of psychological resources in leader–follower dyads

Based on a two-week daily diary study of 31 leader–follower dyads, this article demonstrates that within-person variation in the leader’s level of state core self-evaluations is associated with within-person variation in the follower’s level of state core self-evaluations. Moreover, we provide tentative evidence that this crossover effect might be mediated by transformational leadership behavior. Our study contributes to personality and leadership research by exploring within-leader, within-follower, and within-dyad personality processes. By showing that the personality states of leader and follower fluctuate in sync, we shed light on a new way in which leaders and followers connect.

A school-based parenting program for children with attention-deficit/hyperactivity disorder: Impact on paternal caregivers

Engaging male caregivers within school settings is a major need within the educational field. Paternal engagement may be particularly important for children with attention-deficit/hyperactivity disorder (ADHD). Children with ADHD have increased risk for a number of poor educational outcomes, which may be attenuated by the benefits of positive male caregiver involvement. The Coaching Our Acting Out Children: Heightening Essential Skills (COACHES) program has been illustrated to be an effective approach for engaging, retaining, and improving the parenting of male caregivers of children with ADHD in clinical settings. The present study reports on the efficacy of the COACHES in Schools program, an adaptation intended for deployment in elementary school settings. Sixty-one male caregivers were randomly assigned to COACHES in Schools or a waitlist control. Results indicated that male caregivers in COACHES in Schools used significantly more praise and less negative talk in a parent-child activity relative to male caregivers in the waitlist control at post-treatment and one-month follow-up. Distal outcomes related to child behavior at home and at school were not significantly different. Implications of the results for future studies and continued efforts to engage male caregivers within school settings are discussed.

Individual differences in parent and child average RSA and parent psychological distress influence parent-child RSA synchrony

Parent-child synchrony of respiratory sinus arrhythmia (RSA) varies by risk, but novel approaches are needed to capture individual contributions to synchrony. Multilevel state-trait modeling was applied to examine how parental psychological distress and parent and child average RSA during challenge (reflecting individual regulatory capacities) shaped RSA synchrony in mother-child (n = 71) and father-child (n = 47) interactions. RSA synchrony was curvilinear such that greater in-the-moment RSA reactivity in one partner prompted greater reactivity in the other. Higher risk (lower average RSA; higher distress) predicted in-the-moment RSA withdrawal to partner RSA changes, whereas lower risk (higher average RSA; lower distress) predicted in-the-moment RSA augmentation. In some models, one's higher average RSA prompted the partner's greater reactivity and thus synchrony when parental distress was higher. However, the presence and direction of synchrony was not consistently adaptive nor maladaptive across models, suggesting its meaning relies on theory and the parent and risk factors in question.

Effects of Permethrin or Deltamethrin Exposure in Adult Sprague Dawley Rats on Acoustic and Light Prepulse Inhibition of Acoustic or Tactile Startle

The effects of permethrin (PRM) and deltamethrin (DLM) on acoustic or light prepulse inhibition of the acoustic startle response (ASR) and tactile startle response (TSR) were studied in adult male Sprague Dawley rats. Preliminary studies were conducted to optimize the parameters of light and acoustic prepulse inhibition of ASR and TSR. Once these parameters were set, a new group of rats was administered PRM (0 or 90 mg/kg) or DLM (0 or 25 mg/kg) by gavage in 5 mL/kg corn oil. ASR and TSR were assessed using acoustic or light prepulses 6, 8, and 12 h after PRM and 2, 4, and 6 h after DLM exposure. PRM increased ASR 6 h post-treatment with no interaction with acoustic prepulse levels and with no effect on TSR. When light was used as the prepulse, PRM increased ASR and TSR at 6 h with no interaction with prepulse levels. DLM decreased ASR and TSR on trials without prepulses but not on trials with acoustic prepulses. DLM also decreased ASR when light prepulses were present 4 h post-treatment. A final experiment assessed whether the house light in the test cabinet affected ASR and TSR after PRM or DLM exposure. Rats had increased ASR and TSR when house lights were on compared with when they were off, but lighting did not differentially interact with PRM or DLM. Light and acoustic prepulses of ASR and TSR have different effects depending on the test agent and the test parameters.

Pre-flight exercise and bone metabolism predict unloading-induced bone loss due to spaceflight

Objectives

Bone loss remains a primary health concern for astronauts, despite in-flight exercise. We examined changes in bone microarchitecture, density and strength before and after long-duration spaceflight in relation to biochemical markers of bone turnover and exercise.

Methods

Seventeen astronauts had their distal tibiae and radii imaged before and after space missions to the International Space Station using high-resolution peripheral quantitative CT. We estimated bone strength using finite element analysis and acquired blood and urine biochemical markers of bone turnover before, during and after spaceflight. Pre-flight exercise history and in-flight exercise logs were obtained. Mixed effects models examined changes in bone and biochemical variables and their relationship with mission duration and exercise.

Results

At the distal tibia, median cumulative losses after spaceflight were −2.9% to −4.3% for bone strength and total volumetric bone mineral density (vBMD) and −0.8% to −2.6% for trabecular vBMD, bone volume fraction, thickness and cortical vBMD. Mission duration (range 3.5–7 months) significantly predicted bone loss and crewmembers with higher concentrations of biomarkers of bone turnover before spaceflight experienced greater losses in tibia bone strength and density. Lower body resistance training volume (repetitions per week) increased 3–6 times in-flight compared with pre-spaceflight. Increases in training volume predicted preservation of tibia bone strength and trabecular vBMD and thickness.

Conclusions

Findings highlight the fundamental relationship between mission duration and bone loss. Pre-flight markers of bone turnover and exercise history may identify crewmembers at greatest risk of bone loss due to unloading and may focus preventative measures.

Prior Specification for More Stable Bayesian Estimation of Multilevel Latent Variable Models in Small Samples: A Comparative Investigation of Two Different Approaches

Bayesian approaches for estimating multilevel latent variable models can be beneficial in small samples. Prior distributions can be used to overcome small sample problems, for example, when priors that increase the accuracy of estimation are chosen. This article discusses two different but not mutually exclusive approaches for specifying priors. Both approaches aim at stabilizing estimators in such a way that the Mean Squared Error (MSE) of the estimator of the between-group slope will be small. In the first approach, the MSE is decreased by specifying a slightly informative prior for the group-level variance of the predictor variable, whereas in the second approach, the decrease is achieved directly by using a slightly informative prior for the slope. Mathematical and graphical inspections suggest that both approaches can be effective for reducing the MSE in small samples, thus rendering them attractive in these situations. The article also discusses how these approaches can be implemented in Mplus.

Feature-Based Attentional Weighting and Re-weighting in the Absence of Visual Awareness

Visual attention evolved as an adaptive mechanism allowing us to cope with a rapidly changing environment. It enables the facilitated processing of relevant information, often automatically and governed by implicit motives. However, despite recent advances in understanding the relationship between consciousness and visual attention, the functional scope of unconscious attentional control is still under debate. Here, we present a novel masking paradigm in which volunteers were to distinguish between varying orientations of a briefly presented, masked grating stimulus. Combining signal detection theory and subjective measures of awareness, we show that performance on unaware trials was consistent with visual selection being weighted towards repeated orientations of Gabor patches and reallocated in response to a novel unconsciously processed orientation. This was particularly present in trials in which the prior feature was strongly weighted and only if the novel feature was invisible. Thus, our results provide evidence that invisible orientation stimuli can trigger the reallocation of history-guided visual selection weights.

The Impact of Persistent Irritability on the Medication Treatment of Paediatric Attention Deficit Hyperactivity Disorder

This study compares the efficacy and tolerability of central nervous system (CNS) stimulants in children with attention deficit hyperactivity disorder (ADHD) with and without prominent irritability (IRR) over the course of 30 months. This is a secondary analysis of a study examining growth patterns in medication naïve children with ADHD subsequently treated with CNS stimulants (predominantly OROS-Methylphenidate, up to 54 mg per day) for 30 months. Participants had to meet full diagnostic criteria for ADHD and been treated with CNS stimulants for under 30 days. Children were classified as IRR if they were rated as pretty much or very much on either of the "often angry" or easily annoyed" items plus "lose temper," items of the Disruptive Behavior Disorders Rating Scale (DBDRS). Structured ratings of ADHD symptoms, impairment, side effects, and symptoms of oppositional defiant disorder (ODD) were collected every 2-12 weeks for the duration of the study. Medication use was measured by pill count and parent report. The IRR group comprised 28% of all participants. The IRR group had significantly higher levels of ADHD and ODD symptoms, impairment, and side effects ratings at baseline. In the IRR group, ODD symptoms, emotional lability, and impairment significantly decreased for participants with higher medication use. Total side effects increased for non-IRR participants with higher medication use. Emotional side effects decreased for IRR participants with higher medication use. Central nervous system stimulants were a tolerable and efficacious treatment in treatment naïve youth with ADHD with irritability. Clinical Trials Registration: NCT01109849.

Whole brain proton irradiation in adult Sprague Dawley rats produces dose dependent and non-dependent cognitive, behavioral, and dopaminergic effects

Proton radiotherapy causes less off-target effects than X-rays but is not without effect. To reduce adverse effects of proton radiotherapy, a model of cognitive deficits from conventional proton exposure is needed. We developed a model emphasizing multiple cognitive outcomes. Adult male rats (10/group) received a single dose of 0, 11, 14, 17, or 20 Gy irradiation (the 20 Gy group was not used because 50% died). Rats were tested once/week for 5 weeks post-irradiation for activity, coordination, and startle. Cognitive assessment began 6-weeks post-irradiation with novel object recognition (NOR), egocentric learning, allocentric learning, reference memory, and proximal cue learning. Proton exposure had the largest effect on activity and prepulse inhibition of startle 1-week post-irradiation that dissipated each week. 6-weeks post-irradiation, there were no effects on NOR, however proton exposure impaired egocentric (Cincinnati water maze) and allocentric learning and caused reference memory deficits (Morris water maze), but did not affect proximal cue learning or swimming performance. Proton groups also had reduced striatal levels of the dopamine transporter, tyrosine hydroxylase, and the dopamine receptor D1, effects consistent with egocentric learning deficits. This new model will facilitate investigations of different proton dose rates and drugs to ameliorate the cognitive sequelae of proton radiotherapy.

Negative affect interference and fear of happiness are independently associated with depressive symptoms

OBJECTIVES

Reward devaluation theory (RDT) posits that some depressed individuals avoid positivity due to its previous association with negative outcomes. Behavioral indicators of avoidance of reward support RDT, but self-report indicators have yet to be examined discriminantly. Two candidate self-report measures were examined in relation to depression: negative affect interference (NAI), or the experience of negative affect in response to positivity, and fear of happiness, a fear of prospective happiness.

METHOD

Participants completed measures assessing NAI, fear of happiness scale, and depression online via Amazon's Mechanical Turk at three time points (N = 375). Multilevel modeling examined the relationship between NAI, fear of happiness, and depressive symptoms longitudinally.

RESULTS

NAI and fear of happiness were both positively associated with depressive symptoms. They both uniquely predicted depressive symptoms when included within the same model.

CONCLUSIONS

These findings suggest that different conceptualizations of positivity avoidance are uniquely associated with depressive symptoms.

Assessment of mental health outcomes and associated factors among workers in community-based HIV care centers in the early stage of the COVID-19 outbreak in Mali

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Malian healthcare workers presented mental disorders in the early stage of COVID-19.

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Nurses were at lower risk of mental health disorders than other worker categories.

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Women were at greater risk of mental health disorders than men.

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A lack of protection equipment and nurses was associated with mental disorders.

Background and objectives

In Mali, the non-governmental association (NGO) ARCAD Santé PLUS launched the CovidPrev program in response to the COVID-19 outbreak to ensure continuity of HIV care-related activities. This study aimed to identify individual and structural factors associated with mental health disorders (MHD) in the NGO’s healthcare workers (HCW) in the early stage of the outbreak.

Methods

Data were collected between April 6 and 11, 2020 for 135 HCW in ARCAD Santé PLUS’s 18 community-based HIV care centers. Outcomes corresponded to the PHQ-9, GAD-7 and ISI instruments for depression, anxiety and insomnia, respectively. A general mixture model with a negative binomial distribution was implemented.

Results

Most HCW were men (60.7%) and median age was 40 years IQR[33-46]. Symptoms of depression, anxiety and insomnia were declared by 71.9, 73.3, and 77% participants, respectively. Women were at greater risk of MHD. A lack of personal protection equipment and human resources, especially nurses, was associated with a high risk of MHD.

Conclusions

Health policy must place non-front line HCW, including those in NGOs, at the core of the healthcare system response to the COVID-19 outbreak, as they ensure continuity of care for many diseases including HIV. The efficacy of public health strategies depends on the capacity of HCW to fully with and competently perform their duties.

Late cognitive outcomes among allogeneic stem cell transplant survivors: follow-up data from a 6-year longitudinal study

CONTEXT

Survivors of allogeneic hematopoietic stem cell transplantation (alloHCT) may experience cognitive impairment over time post-treatment, but early identification of these individuals is limited.

OBJECTIVES

We previously reported a prospective evaluation of cognitive functioning over the first 6 months of alloHCT. Here, we report an extension of this study, with specific aims to (1) evaluate the trajectory of cognitive outcomes over the first 6 years post-alloHCT, and (2) determine the extent to which late cognitive impairment is predicted by earlier impairment.

METHODS

Participants completed objective and subjective cognitive measures before alloHCT, and at 100 days, 6 months, and 6 years post-alloHCT. Outcome trajectories were determined using linear mixed effects models. Relationships between early and late cognitive impairment were assessed using logistic regression and receiver operator curves.

RESULTS

This analysis is based on longitudinal data from 59 participants, of whom 20 provided data at 6-year follow-up. Longitudinal models revealed an overall stability of cognitive outcomes over time, except for psychomotor efficiency/processing speed performance, which significantly improved (p = .049). However, poor learning/memory and cognitive complaints were persistently observed. At 6 years, 40% of relapse-free survivors met the impairment criteria. Impairment at 100 days was associated with impairment 6 years (OR = 20.00, p = .028) and demonstrated good accuracy in classifying those who were impaired and not impaired at 6 years (AUC = .79; 95% CI = .56-1.00).

CONCLUSION

Poor cognitive outcomes among long-term alloHCT survivors are associated with cognitive functioning during the early post-treatment period. Early identification of survivors likely to experience poor cognitive outcomes may be possible, enabling timely intervention to mitigate long-term negative impacts.

Extending the I-squared statistic to describe treatment effect heterogeneity in cluster, multi-centre randomized trials and individual patient data meta-analysis

Treatment effect heterogeneity is commonly investigated in meta-analyses to identify if treatment effects vary across studies. When conducting an aggregate level data meta-analysis it is common to describe the magnitude of any treatment effect heterogeneity using the I-squared statistic, which is an intuitive and easily understood concept. The effect of a treatment might also vary across clusters in a cluster randomized trial, or across centres in multi-centre randomized trial, and it can be of interest to explore this at the analysis stage. In cross-over trials and other randomized designs, in which clusters or centres are exposed to both treatment and control conditions, this treatment effect heterogeneity can be identified. Here we derive and evaluate a comparable I-squared measure to describe the magnitude of heterogeneity in treatment effects across clusters or centres in randomized trials. We further show how this methodology can be used to estimate treatment effect heterogeneity in an individual patient data meta-analysis.

Do therapist effects really impact estimates of within-patient mechanisms of change? A Monte Carlo simulation study

Objective: Existing evidence highlights the importance of modeling differential therapist effectiveness when studying psychotherapy outcome. However, no study to date examined whether this assertion applies to the study of within-patient effects in mechanisms of change. The study investigated whether therapist effects should be modeled when studying mechanisms of change on a within-patient level. Methods: We conducted a Monte Carlo simulation study, varying patient- and therapist level sample sizes, degree of therapist-level nesting (intra-class correlation), balanced vs. unbalanced assignment of patients to therapists, and fixed vs random within-patient coefficients. We estimated all models using longitudinal multilevel and structural equation models that ignored (2-level model) or modeled therapist effects (3-level model). Results: Across all conditions, 2-level models performed equally or were superior to 3-level models. Within-patient coefficients were unbiased in both 2- and 3-level models. In 3-level models, standard errors were biased when number of therapists was small, and this bias increased in unbalanced designs. Ignoring random slopes led to biased standard errors when slope variance was large; but 2-level models still outperformed 3-level models. Conclusions: In contrast to treatment outcome research, when studying mechanisms of change on a within-patient level, modeling therapist effects may even reduce model performance and increase bias.

The Performance of Multivariate Methods for Two-Group Comparisons with Small Samples and Incomplete Data

In intervention studies having multiple outcomes, researchers often use a series of univariate tests (e.g., ANOVAs) to assess group mean differences. Previous research found that this approach properly controls Type I error and generally provides greater power compared to MANOVA, especially under realistic effect size and correlation combinations. However, when group differences are assessed for a specific outcome, these procedures are strictly univariate and do not consider the outcome correlations, which may be problematic with missing outcome data. Linear mixed or multivariate multilevel models (MVMMs), implemented with maximum likelihood estimation, present an alternative analysis option where outcome correlations are taken into account when specific group mean differences are estimated. In this study, we use simulation methods to compare the performance of separate independent samples t tests estimated with ordinary least squares and analogous t tests from MVMMs to assess two-group mean differences with multiple outcomes under small sample and missingness conditions. Study results indicated that a MVMM implemented with restricted maximum likelihood estimation combined with the Kenward-Roger correction had the best performance. Therefore, for intervention studies with small N and normally distributed multivariate outcomes, the Kenward-Roger procedure is recommended over traditional methods and conventional MVMM analyses, particularly with incomplete data.

Time for bed! Earlier sleep onset is associated with longer nighttime sleep duration during infancy

OBJECTIVE/BACKGROUND

Clinical recommendations include putting infants to bed using a consistent bedtime routine at an appropriate hour to promote longer nighttime sleep. Actigraphy was used in this exploratory study to examine how bedtime routines and nighttime sleep onset were associated with nighttime total sleep time (TST) and efficiency from 6 to 24 weeks of age.

PATIENTS/METHODS

Infants (n = 24) wore sleep actigraphs for three, one-week periods at 6, 15, and 24 weeks of age. Nighttime TST, sleep efficiency, sleep onset and offset were quantified. Mothers reported on infant bedtime routines using the Brief Infant Sleep Questionnaire at each age. Multilevel models examined between- and within-person associations.

RESULTS

As infants aged, sleep onset was earlier, and bedtime routines became shorter (p's < 0.05). Infants fell asleep between 7 and 8:00PM on 24% of the nights. Most mothers (70%) reported that they often fed infants to sleep for the night. For every 1 h earlier in infants' usual sleep onset, nighttime TST was 34.4 min longer that night (p < 0.01). Infants with earlier than usual sleep onset had slightly earlier sleep offset the next morning (8.4 min for every 1 h earlier in onset; p = 0.02). Between-person analyses showed similar patterns. Infants with a more consistent bedtime routine and who were not typically fed to sleep at bedtime had longer nighttime TST at 6 weeks, with a trend or no association at later ages.

CONCLUSION

Infants who fell asleep earlier also slept longer at night. Keeping infants up later in hopes of them sleeping in longer may be counterproductive.

Statistical analysis of longitudinal data on tumour growth in mice experiments

We consider mice experiments where tumour cells are injected so that a tumour starts to grow. When the tumour reaches a certain volume, mice are randomized into treatment groups. Tumour volume is measured repeatedly until the mouse dies or is sacrificed. Tumour growth rates are compared between groups. We propose and evaluate linear regression for analysis accounting for the correlation among repeated measurements per mouse. More specifically, we examined five models with three different variance-covariance structures in order to recommend the least complex method for small to moderate sample sizes encountered in animal experiments. We performed a simulation study based on data from three previous experiments to investigate the properties of estimates of the difference between treatment groups. Models were estimated via marginal modelling using generalized least squares and restricted maximum likelihood estimation. A model with an autoregressive (AR-1) covariance structure was efficient and unbiased retaining nominal coverage and type I error when the AR-1 variance-covariance matrix correctly specified the association between repeated measurements. When the variance-covariance was misspecified, that model was still unbiased but the type I error and the coverage rates were affected depending on the degree of misspecification. A linear regression model with an autoregressive (AR-1) covariance structure is an adequate model to analyse experiments that compare tumour growth rates between treatment groups.

Auditory Detection Thresholds and Cochlear Resistivity Differ Between Pediatric Cochlear Implant Listeners With Enlarged Vestibular Aqueduct and Those With Connexin-26 Mutations

Purpose The goal of this study was to evaluate differences in the electrode-neuron interface as a function of hearing loss etiology in pediatric cochlear implant (CI) listeners with enlarged vestibular aqueduct (EVA) syndrome and in those with autosomal recessive connexin-26 mutations (DFNB1). Method Fifteen implanted ears (9 participants, 5 ears with EVA, 10 ears with DFNB1) were assessed. Single-channel auditory detection thresholds were measured using broad and spatially focused electrode configurations (steered quadrupolar; focusing coefficients = 0 and 0.9). Cochlear resistivity estimates were obtained via electrode impedances and electrical field imaging. Between-group differences were evaluated using linear mixed-effects models. Results Children with EVA had significantly higher auditory detection thresholds than children with DFNB1, irrespective of electrode configuration. Between-group differences in thresholds were more pronounced on apical electrodes than on basal electrodes. In the apex, electrode impedances and electrical field imaging values were higher for children with EVA than for those with DFNB1. Conclusions The electrode-neuron interface differs between pediatric CI listeners with DFNB1 and those with EVA. It is possible that optimal clinical interventions may depend, in part, on hearing loss etiology. Future investigations with large samples should investigate individualized CI programming strategies for listeners with EVA and DFNB1.

Phenolic Compound Induction in Plant-Microbe and Plant-Insect Interactions: A Meta-Analysis

Plants rely on a variety of ways to protect themselves from being fed upon, including de novo production of specific compounds such as those termed as phenolics. Phenolics are often described as important in plant health and numerous studies have concluded they increase as a result of insect feeding, pathogen infection, or beneficial microorganism colonization. However, there are some studies reaching differing conclusions. Therefore, meta-analyses were conducted to observe whether common trends in phenolic induction in plants can be made when they become hosts to insects or microorganisms. Four hypotheses were tested. The first was that total phenolics increase as a generic response, and meta-analyses confirmed that this occurs when plants are infested with insects or colonized by bacterial or fungal microorganisms, but not for oomycetes. The second hypothesis was that phenolic induction is different when a beneficial microorganism colonizes a plant vs. when a plant is infected by a pathogen. Beneficial bacteria, pathogenic bacteria, and beneficial fungi produced increased phenolic levels in plant hosts, but fungal pathogens did not. The third hypothesis was that insect feeding method on plant hosts determines if phenolics are induced. Chewing induced phenolics but piercing-sucking and wood-boring did not. Lastly, we used meta-analyses to determine if annual or perennials rely on phenolic induction in different amounts, and even though annuals had significantly increased phenolic levels but perennials did not, it was observed that phenolic induction was not statistically different when plant type was considered. These results demonstrate that phenolic induction is a common response in plant hosts exposed to feeding or colonization, with specific exceptions such a pathogenic fungi and piercing-sucking insects.

Dimensions of HR differentiation

Purpose

The purpose of this paper is to introduce the idea of dimensions of human resource (HR) differentiation defined as characteristics which may influence employees’ attitudinal responses to unequal working conditions. The paper concentrates on five dimensions: the number of segments, the strength of HR differentiation, its content, absolute and relative stability and analyses how they could moderate the relationship between employee segment membership (core or peripheral) and job satisfaction, affective commitment and turnover intentions.

Design/methodology/approach

The research hypotheses were tested on a sample of 978 employees from Polish co-operative banks. Hierarchical linear modelling was used to examine the moderating effect of the dimensions of HR differentiation.

Findings

Results indicate that employees in the core segment experience higher job satisfaction, affective commitment and lower turnover intentions than those in the peripheral segment. The moderating effect of HR differentiation dimensions occurred to be relatively weak. However, when the interaction effect was significant, the results always supported the hypotheses, indicating that the number of segments and the strength of HR differentiation are positively correlated with the size of the differences between the core and peripheral employees’ positive attitudes level.

Originality/value

This is the first attempt to classify several dimensions of HR differentiation and formulate their hypothetical moderating effect drawing on human capital theory, social exchange theory and social comparison theory.

Patient-reported outcome measures after treatment for prostate cancer: Results from the Danish Prostate Cancer Registry (DAPROCAdata)

PURPOSE

This study compares the side effects of active surveillance, prostatectomy, radiation with or without adjuvant endocrine therapy, watchful waiting, and palliative therapy on patient-reported outcomes in a nationwide, population-based cohort of Danish men with prostate cancer.

METHODS

A total of 15,465 participants completed questionnaires over a 5 year period (2011-2016). Condition-specific quality of life, focusing on urinary function, bowel incontinence, sexual function, and hormonal symptoms were investigated using the validated EPIC-26 questionnaire at diagnosis, 1 year- and 3- year follow-up. Patients were identified from the Danish Prostate Cancer Registry with data-linked to several national healthcare registries. Longitudinal analysis with linear mixed effects models were fitted to compare changes over time on quality of life symptom scores for five treatment modalities, adjusting for age, clinical TNM stage, PSA value, Gleason score, Charlson Comorbidity score, education, disposable income, and urbanization measured at time of prostate cancer diagnosis.

RESULTS

There was a more than10-point decrease in mean scores across all symptom domains at 1-year follow-up. Thereafter mean scores for all symptom domains improved marginally and remained relatively unchanged at 3-year follow-up. Prostatectomy had the greatest negative effect on sexual function and urinary incontinence. Overall quality of life was most adversely affected by sexual function, regardless of treatment modality.

CONCLUSION

Clinical interventions for improving symptoms should focus particularly on the first year after prostate cancer diagnosis. Greater emphasis on improving sexual function should be practiced in clinical and rehabilitative care, since this area has the single greatest impact on symptom-specific QoL after primary treatment for prostate cancer.

Effect Partitioning in Cross-Sectionally Clustered Data Without Multilevel Models

Effect partitioning is almost exclusively performed with multilevel models (MLMs) - so much so that some have considered the two to be synonymous. MLMs are able to provide estimates with desirable statistical properties when data come from a hierarchical structure; but the random effects included in MLMs are not always integral to the analysis. As a result, other methods with relaxed assumptions are viable options in many cases. Through empirical examples and simulations, we show how generalized estimating equations (GEEs) can be used to effectively partition effects without random effects. We show that more onerous steps of MLMs such as determining the number of random effects and the structure for their covariance can be bypassed with GEEs while still obtaining identical or near-identical results. Additionally, violations of distributional assumptions adversely affect estimates with MLMs but have no effect on GEEs because no such assumptions are made. This makes GEEs a flexible alternative to MLMs with minimal assumptions that may warrant consideration. Limitations of GEEs for partitioning effects are also discussed.

Enhanced gaze-following behavior in Deaf infants of Deaf parents

Gaze following plays a role in parent-infant communication and is a key mechanism by which infants acquire information about the world from social input. Gaze following in Deaf infants has been understudied. Twelve Deaf infants of Deaf parents (DoD) who had native exposure to American Sign Language (ASL) were gender-matched and age-matched (±7 days) to 60 spoken-language hearing control infants. Results showed that the DoD infants had significantly higher gaze-following scores than the hearing infants. We hypothesize that in the absence of auditory input, and with support from ASL-fluent Deaf parents, infants become attuned to visual-communicative signals from other people, which engenders increased gaze following. These findings underscore the need to revise the 'deficit model' of deafness. Deaf infants immersed in natural sign language from birth are better at understanding the signals and identifying the referential meaning of adults' gaze behavior compared to hearing infants not exposed to sign language. Broader implications for theories of social-cognitive development are discussed. A video abstract of this article can be viewed at https://youtu.be/QXCDK_CUmAI.

What Affects Attendance and Engagement in a Parenting Program in South Africa?

Parenting programs are a promising approach to improving family well-being. For families to benefit, programs need to be able to engage families actively in the interventions. Studies in high-income countries show varying results regarding whether more disadvantaged families are equally engaged in parenting interventions. In low- and middle-income countries (LMICs), almost nothing is known about the patterns of participation in parent training. This paper examines group session attendance and engagement data from 270 high-risk families enrolled in the intervention arm of a cluster-randomized controlled trial in South Africa. The trial evaluated a 14-week parenting intervention aiming to improve parenting and reduce maltreatment by caregivers. The intervention was delivered in 20 groups, one per study cluster, with 8 to 16 families each. Overall, caregivers attended 50% of group sessions and children, 64%. Using linear multilevel models with Kenward-Roger correction, we examined child and caregiver baseline characteristics as predictors of their attendance and engagement in the group sessions. Variables examined as predictors included measures of economic, educational, and social and health barriers and resources, as well as family problems and sociodemographic characteristics. Overall, the study yielded no evidence that the level of stressors, such as poverty, was related to attendance and engagement. Notably, children from overcrowded households attended on average 1.2 more sessions than their peers. Our findings suggest it is possible to engage highly disadvantaged families that face multiple challenges in parenting interventions in LMICs. However, some barriers such as scheduling, and alcohol and substance use, remain relevant.

Identifying and quantifying variation between healthcare organisations and geographical regions: using mixed-effects models

When the degree of variation between healthcare organisations or geographical regions is quantified, there is often a failure to account for the role of chance, which can lead to an overestimation of the true variation. Mixed-effects models account for the role of chance and estimate the true/underlying variation between organisations or regions. In this paper, we explore how a random intercept model can be applied to rate or proportion indicators and how to interpret the estimated variance parameter.