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Convolutional Neural Networks (CNNs) have shown remarkable prowess in detecting P300, an Event-Related Potential (ERP) crucial in Brain–Computer Interfaces (BCIs). Researchers persistently seek simple and efficient CNNs for P300 detection, exemplified by models like DeepConvNet, EEGNet, and SepConv1D. Noteworthy progress has been made, manifesting in reducing parameters from millions to hundreds while sustaining state-of-the-art performance. However, achieving further simplification or performance improvement beyond SepConv1D appears challenging due to inherent oversimplification. This study explores landmark CNNs and P300 data with the aid of Explainable AI, proposing a simpler yet superior-performing CNN architecture which incorporates (1) precise separable convolution for feature extraction of P300 data, (2) adaptive activation function tailored for P300 data, and (3) customized large learning rate schedules for training P300 data. Termed the Minimalist CNN for P300 detection (P300MCNN), this novel model is characterized by its requirement of the fewest filters and epochs to date, concurrently achieving best performance in cross-subject P300 detection. P300MCNN not only introduces groundbreaking concepts for CNN architectures in P300 detection but also showcases the importance of Explainable AI in demystifying the “black box” design of CNNs.

The cerebral cortex is characterized as the integration of distinct functional principles that correspond to basic primary functions, such as vision and movement, and domain‐general functions, such as attention and cognition. Diffusion embedding approach is a novel tool to describe transitions between different functional principles, and has been successively applied to investigate pathological conditions in between‐group designs. What still lacking and urgently needed is the efficacy of this method to differentiate within‐subject circumstances. In this study, we applied the diffusion embedding to eyes closed (EC) and eyes on (EO) resting‐state conditions from 145 participants. We found significantly lower within‐network dispersion of visual network (VN) (p = 7.3 × 10−4) as well as sensorimotor network (SMN) (p = 1 × 10−5) and between‐network dispersion of VN (p = 2.3 × 10−4) under EC than EO, while frontoparietal network (p = 9.2 × 10−4) showed significantly higher between‐network dispersion during EC than EO. Test–retest reliability analysis further displayed fair reliability (intraclass correlation coefficient [ICC] < 0.4) of the network dispersions (mean ICC = 0.116 ± 0.143 [standard deviation]) except for the within‐network dispersion of SMN under EO (ICC = 0.407). And the reliability under EO was higher but not significantly higher than reliability under EC. Our study demonstrated that the diffusion embedding approach that shows fair reliability is capable of distinguishing EC and EO resting‐state conditions, such that this method could be generalized to other within‐subject designs. [ABSTRACT FROM AUTHOR]

Background: Evidence suggests that physical activity (PA) during childhood and adolescence is crucial as it usually results in adequate PA levels in adulthood. Given the ubiquitous use of smartphones by adolescents, these devices may offer feasible means to reach young populations and deliver interventions aiming to increase PA participation and decrease sedentary time. To date, very few studies have reported smartphone-based interventions promoting PA for adolescents. In addition, most available fitness apps do not include the latest evidence-based content. Objective: This paper described the systematic development of a behavior change, theory-informed Mobile App for Physical Activity intervention with personalized prompts for adolescents aged 16 to 18 years. The within-subject trial results provided the first evidence of the general effectiveness of the intervention based on the outcomes step count, sedentary time, and moderate to vigorous PA (MVPA) minutes. The effectiveness of the intervention component personalized PA prompt was also assessed. Methods: A 4-week within-subject trial with 18 healthy adolescents aged 16 to 18 years was conducted (mean age 16.33, SD 0.57 years). After the baseline week, the participants used the Mobile App for Physical Activity intervention (Fitbit fitness tracker+app), which included a daily personalized PA prompt delivered via a pop-up notification. A paired 1-tailed t test was performed to assess the effectiveness of the intervention. Change-point analysis was performed to assess the effectiveness of a personalized PA prompt 30 and 60 minutes after prompt delivery. Results: The results showed that the intervention significantly reduced sedentary time in adolescents during the first week of the trial (t17=-1.79; P=.04; bootstrapped P=.02). This trend, although remaining positive, diminished over time. Our findings indicate that the intervention had no effect on metabolic equivalent of task-based MVPA minutes, although the descriptive increase may give reason for further investigation. Although the results suggested no overall change in heart rate-based MVPA minutes, the results from the change-point analyses suggest that the personalized PA prompts significantly increased heart rate per minute during the second week of the study (t16=1.84; P=.04; bootstrapped P=.04). There were no significant increases in participants' overall step count; however, the personalized PA prompts resulted in a marginally significant increase in step counts per minute in the second week of the study (t17=1.35; P=.09; bootstrapped P=.05). Conclusions: The results of the trial provide preliminary evidence of the benefit of the Mobile App for Physical Activity intervention for modest yet significant reductions in participants' sedentary time and the beneficial role of personalized PA prompts. These results also provide further evidence of the benefits and relative efficacy of personalized activity suggestions for inclusion in smartphone-based PA interventions. This study provides an example of how to guide the development of smartphone-based mobile health PA interventions for adolescents. [ABSTRACT FROM AUTHOR]

Substance Use Disorders (SUDs) are an impactful problem characterized by chronic relapse and engagement in drug‐related behaviors at the expense of non‐drug behaviors. Brain regions implicated in drug and non‐drug‐related behaviors often overlap, complicating investigations of neurobiological mechanisms underlying SUDs. Here we presented a within‐subject model for studying self‐administration, reinforcer competition, extinction, and cued reinstatement of cocaine‐ and food‐seeking in rats. Due to differences in cocaine‐ and food‐reinforced behavior, we transformed data to proportions of baseline, revealing increased resistance to extinction and disproportionately greater cued reinstatement of cocaine seeking relative to food seeking. Consistent with previous reports, females showed greater preference for cocaine reinforcement than males, though these findings failed to reach statistical significance. To demonstrate the model's utility for investigating neurobiological mechanisms, we included proof‐of‐concept calcium imaging data demonstrating the utility of the behavioral model for detecting cellular activity patterns associated with cocaine‐ and food‐seeking behaviors. Future studies utilizing this model should improve understanding of the development and expression of pathological behaviors characteristic of SUDs in humans, sex differences in these behaviors, and their neurobiological correlates. Thus, the model has utility for improving understanding of SUDs, leading to novel treatments to reduce the pathological behaviors associated with SUDs. [ABSTRACT FROM AUTHOR]

Bottle‐fed infants are at higher risk for rapid weight gain compared with breastfed infants. Few studies have attempted to disentangle effects of feeding mode, milk composition and relevant covariates on feeding interactions and outcomes. The objective of the present study was to compare effects of breastfeeding directly at the breast versus bottle‐feeding expressed breast milk on feeding interactions. Mothers with <6‐month‐old infants (n = 47) participated in two counterbalanced, feeding observations. Mothers breastfed their infants directly from the breast during one visit (breast condition) and bottle‐fed their infants expressed breast milk during the other (bottle condition). Masked raters later coded videos using the Nursing Child Assessment Parent–Child Interaction Feeding Scale. Infant intake was assessed. Mothers self‐reported sociodemographic characteristics, infant feeding patterns (i.e. percentage of daily feedings from bottles) and level of pressuring feeding style. Mother and infant behaviours were similar during breast and bottle conditions. Percent bottle‐feeding moderated effects of condition on intake (P = 0.032): greater percent bottle‐feeding predicted greater intake during the bottle compared with breast condition. Effects of feeding mode were not moderated by parity or pressuring feeding style, but, regardless of condition, multiparous mothers fed their infants more than primiparous mothers (P = 0.028), and pressuring feeding style was positively associated with infant intake (P = 0.045). Findings from the present study do not support the hypothesis that feeding mode directly impacts dyadic interaction for predominantly breastfeeding mothers and infants, but rather suggest between‐subject differences in feeding experiences and styles predict feeding outcomes for this population. [ABSTRACT FROM AUTHOR]

Affect experienced during an exercise session is supposed to predict future exercise behavior. However, empirical evidence reveals high variability in affective response to different exercise modalities. Thus, the purpose of the present study was to compare acute affective response and its variation during three different endurance exercise modalities: (a) moderate-intensity continuous exercise (MICE), (b) vigorous-intensity continuous exercise (VICE), and (c) high-intensity interval exercise (HIIE). Using the dual-mode theory as a theoretical framework, cognitive and interoceptive factors were considered as potential predictors of in-task affective response. In a within-subject design, 40 insufficiently active healthy participants (aged from 20 to 40 years) attended three sessions per exercise modality on a cycle ergometer. Affective valence (measured by the Feeling Scale), two cognitive factors (perceived competence and awareness of interoceptive cues), and one interoceptive factor (heart rate) were assessed before, during, and after each exercise session. Mixed models with three levels (subject, exercise session, and time point) revealed more positive affective valence during MICE compared with VICE (p < 0.001) and HIIE (p < 0.01), while there was no significant difference between the latter two. Levene's test results showed the highest variability of in-task affective valence during VICE (ps < 0.01). Regarding the course across the session, MICE was associated with a constant slight increase in affective valence from pre- to post-exercise (p < 0.05), whereas VICE and HIIE caused a decline in pleasure, followed by an affective rebound immediately after exercise termination (ps < 0.01). The highest importance of cognitive and interoceptive factors for in-task affective valence was observed in VICE (ps < 0.05). The current findings provide support for the tenets of the dual-mode theory, however, indicating that there may be differences in the affect-intensity relationship between continuous and interval exercise. In conclusion, the study results concerning previously insufficiently active individuals extend the knowledge of how exercise can positively shape affective well-being depending on exercise modality and psychophysiological influences. This knowledge enables public health practitioners to design more individualized activity recommendations, thereby improving the subjective experience of exercise.

Affect experienced during an exercise session is supposed to predict future exercise behavior. However, empirical evidence reveals high variability in affective response to different exercise modalities. Thus, the purpose of the present study was to compare acute affective response and its variation during three different endurance exercise modalities: (a) moderate-intensity continuous exercise (MICE), (b) vigorous-intensity continuous exercise (VICE), and (c) high-intensity interval exercise (HIIE). Using the dual-mode theory as a theoretical framework, cognitive and interoceptive factors were considered as potential predictors of in-task affective response. In a within-subject design, 40 insufficiently active healthy participants (aged from 20 to 40 years) attended three sessions per exercise modality on a cycle ergometer. Affective valence (measured by the Feeling Scale), two cognitive factors (perceived competence and awareness of interoceptive cues), and one interoceptive factor (heart rate) were assessed before, during, and after each exercise session. Mixed models with three levels (subject, exercise session , and time point) revealed more positive affective valence during MICE compared with VICE (p < 0.001) and HIIE (p < 0.01), while there was no significant difference between the latter two. Levene's test results showed the highest variability of in-task affective valence during VICE (p s < 0.01). Regarding the course across the session, MICE was associated with a constant slight increase in affective valence from pre- to post-exercise (p < 0.05), whereas VICE and HIIE caused a decline in pleasure, followed by an affective rebound immediately after exercise termination (p s < 0.01). The highest importance of cognitive and interoceptive factors for in-task affective valence was observed in VICE (p s < 0.05). The current findings provide support for the tenets of the dual-mode theory, however, indicating that there may be differences in the affect-intensity relationship between continuous and interval exercise. In conclusion, the study results concerning previously insufficiently active individuals extend the knowledge of how exercise can positively shape affective well-being depending on exercise modality and psychophysiological influences. This knowledge enables public health practitioners to design more individualized activity recommendations, thereby improving the subjective experience of exercise. [ABSTRACT FROM AUTHOR]

Knowledge of motor variability is an essential step towards understanding a subject's working activity. This study aims to assess within-subject and between-subject variability and the intrinsic factors that drive variability during a clip fitting task in the laboratory. Muscular activity is recorded on six muscles of each upper limb. Four metrics are used: two characterizing muscular load and two characterizing intra-clip fitting dispersion. Factor analyses and muscle-by-muscle analyses are conducted. Independent variables linked to subject characteristics and to task performance are considered. Factor analysis reveals the combined activity of the different muscles. The short and highly constrained task shows both within-subject variability and between-subject variability. The latter predominates. Each of the independent variables induces a variability which affects the muscular load metrics, although only a few affect the within-clip fitting dispersion. The muscle-by-muscle and factorial score analyses results are consistent. [ABSTRACT FROM AUTHOR]

Over the past decade convolutional neural networks (CNNs) have become the driving force of an ever-increasing set of applications, achieving state-of-the-art performance. Modern CNN architectures are often composed of many convolutional and some fully connected layers, and have thousands or millions of parameters. CNNs have shown to be effective in the detection of Event-Related Potentials from electroencephalogram (EEG) signals, notably the P300 component which is frequently employed in Brain-Computer Interfaces (BCIs). However, for this task, the increase in detection rates compared to approaches based on human-engineered features has not been as impressive as in other areas and might not justify such a large number of parameters. In this paper, we study the performance of existing CNN architectures with diverse complexities for single-trial within-subject and cross-subject P300 detection on four different datasets. We also proposed SepConv1D, a very simple CNN architecture consisting of a single depthwise separable 1D convolutional layer followed by a fully connected Sigmoid classification neuron. We found that with as few as four filters in its convolutional layer and an overall small number of parameters, SepConv1D obtained competitive performances in the four datasets. We believe these results may represent an important step towards building simpler, cheaper, faster, and more portable BCIs. [ABSTRACT FROM AUTHOR]

Background: Urine amino acid analysis is used for the assessment of various diseases. The aim of this study was to estimate the valid biological variation (BV) components (within- and between-subjects) required for the safe clinical application of free urine amino acids. Methods: First morning void urine samples were taken from 12 healthy subjects (five females, seven males) once a week for 10 consecutive weeks, and amino acid analysis was performed using an Agilent 6470 triple quadrupole tandem mass spectrometer instrument. The obtained data were subjected to normality, outlier and variance homogeneity analyses prior to coefficient of variation (CV) analysis. Within- and between-subject BV values (CVI and CVG) of 39 amino acids were determined for all subjects. In addition, the index of individuality (II), reference change value (RCV), imprecision, bias and total error were estimated using BV data obtained from our study. Results: The CVI values ranged from 8.9 (histidine) to 36.8% (trans-4-hydroxyprolin), while the CVG values ranged from 25.0 (1-methyl-L-histidine) to 63.3% (phenylalanine). The II value of most amino acids was less than 0.6 and ranged between 0.21 and 0.88. The imprecision, bias and total error ranged between 4.45 and 16.6, between 7.69 and 16.6, and between 18.4 and 43.2, respectively. Conclusions: This study, designed according to a rigorous protocol, has the feature of being the first to give information about BV data of urine amino acids. We believe that the reference intervals have a limitation in the evaluation of consecutive results from an individual, so the use of RCV would be more appropriate. [ABSTRACT FROM AUTHOR]

Online travel agencies advertise limited availability by indicating room inventories and the number of other travelers. This research investigates the effect of limited availability using supply and demand-based scarcity with price promotion on traveler decisions and cognitive dissonance. Two experimental approaches (between and within subjects) examine the causal effects of scarcity. Demand-based scarcity decreases booking decisions while supply-based scarcity increases booking decisions, especially at a discounted price in a within-subjects design. Scarcity produces cognitive dissonance and intention to undo the decisions. For effective applications, scarcity messages should be transparent, and include non-scarce options for comparison. Multiple scarcity messages minimize undo-intentions. [ABSTRACT FROM AUTHOR]

Research employing single-choice paradigms in which an infant is asked to make a single choice between two puppets suggest that infants show a preference for prosocial others and those who are similar to themselves. However, the extent to which infants’ preference for similar others is stable is unknown, as are other factors within the paradigm that may influence infants’ choices. The purpose of this study (two experiments, N = 44 infants, aged 8–15 months) was to replicate and extend previous work by including (1) within-subject repeated measures and (2) an experimental manipulation of a plausible demand characteristic. Results for the first-choice trial indicated a majority of the infants did not choose the similar puppet. Results from the within-subject repeated trials also indicated that a majority of the infants did not choose the similar puppet but a majority did choose a puppet from the same side. The experimental manipulation of the demand characteristic showed no effect on infant puppet choices. These results suggest that a closer examination of the single-choice puppet paradigm for assessing infants’ social evaluation is warranted. These findings also support recommendations made by others, including publishing null findings, standardizing data collection and reporting methods, and examining individual differences by employing within-subject designs with repeated measures.

Group-level repeated measurements are common in neuroimaging, yet their analysis remains complex. Although a variety of specialized tools now exist, it is surprising that to-date there has been no clear discussion of how repeated-measurements can be analyzed appropriately using the standard general linear model approach, as implemented in software such as SPM and FSL. This is particularly surprising given that these implementations necessitate the use of multiple models, even for seemingly conventional analyses, and that without care it is very easy to specify contrasts that do not correctly test the effects of interest. Despite this, interest in fitting these types of models using conventional tools has been growing in the neuroimaging community. As such it has become even more important to elucidate the correct means of doing so. To begin, this paper will discuss the key concept of the expected mean squares (EMS) for defining suitable F-ratios for testing hypotheses. Once this is understood, the logic of specifying correct repeated measurements models in the GLM should be clear. The ancillary issue of specifying suitable contrast weights in these designs will also be discussed, providing a complimentary perspective on the EMS. A set of steps will then be given alongside an example of specifying a 3-way repeated-measures ANOVA in SPM. Equivalency of the results compared to other statistical software will be demonstrated. Additional issues, such as the inclusion of continuous covariates and the assumption of sphericity, will also be discussed. The hope is that this paper will provide some clarity on this confusing topic, giving researchers the confidence to correctly specify these forms of models within traditional neuroimaging analysis tools.

Research employing single-choice paradigms in which an infant is asked to make a single choice between two puppets suggest that infants show a preference for prosocial others and those who are similar to themselves. However, the extent to which infants' preference for similar others is stable is unknown, as are other factors within the paradigm that may influence infants' choices. The purpose of this study (two experiments, N = 44 infants, aged 8–15 months) was to replicate and extend previous work by including (1) within-subject repeated measures and (2) an experimental manipulation of a plausible demand characteristic. Results for the first-choice trial indicated a majority of the infants did not choose the similar puppet. Results from the within-subject repeated trials also indicated that a majority of the infants did not choose the similar puppet but a majority did choose a puppet from the same side. The experimental manipulation of the demand characteristic showed no effect on infant puppet choices. These results suggest that a closer examination of the single-choice puppet paradigm for assessing infants' social evaluation is warranted. These findings also support recommendations made by others, including publishing null findings, standardizing data collection and reporting methods, and examining individual differences by employing within-subject designs with repeated measures. [ABSTRACT FROM AUTHOR]

Group-level repeated measurements are common in neuroimaging, yet their analysis remains complex. Although a variety of specialized tools now exist, it is surprising that to-date there has been no clear discussion of how repeated-measurements can be analyzed appropriately using the standard general linear model approach, as implemented in software such as SPM and FSL. This is particularly surprising given that these implementations necessitate the use of multiple models, even for seemingly conventional analyses, and that without care it is very easy to specify contrasts that do not correctly test the effects of interest. Despite this, interest in fitting these types of models using conventional tools has been growing in the neuroimaging community. As such it has become even more important to elucidate the correct means of doing so. To begin, this paper will discuss the key concept of the expected mean squares (EMS) for defining suitable F -ratios for testing hypotheses. Once this is understood, the logic of specifying correct repeated measurements models in the GLM should be clear. The ancillary issue of specifying suitable contrast weights in these designs will also be discussed, providing a complimentary perspective on the EMS. A set of steps will then be given alongside an example of specifying a 3-way repeated-measures ANOVA in SPM. Equivalency of the results compared to other statistical software will be demonstrated. Additional issues, such as the inclusion of continuous covariates and the assumption of sphericity, will also be discussed. The hope is that this paper will provide some clarity on this confusing topic, giving researchers the confidence to correctly specify these forms of models within traditional neuroimaging analysis tools. [ABSTRACT FROM AUTHOR]

Obsessive-compulsive symptoms (OCS) are frequently reported in patients with schizophrenia and have been associated with subjective distress and higher impairment. Recent studies suggest fluctuation in co-occurring OCS and associations with the course of psychotic symptoms. Current evidence is limited by few studies with long assessments intervals and a sole focus on between-subject comparisons. The aim of this study was to specifically investigate co-variation of symptom domains over time within individuals. Patients with a psychotic disorder (n = 56) and un-affected siblings (n = 49) completed monthly assessments of clinical and subclinical symptoms over 6 months. Mixed-model multilevel analyses examined the variability and relationship between OCS and positive, negative, and depressive symptoms on the between- and within-subject level. Symptom domains were associated across subjects and assessment times, in patients and siblings, with the strongest association between OCS and (subclinical) positive symptoms. Within-subjects, substantial variability and co-variation of all symptom domains was found. Particularly, between-subject differences in positive symptoms and within-subject change in depressive symptoms predicted subsequent OCS in patients 1 months later. This is the first prospective study disaggregating between and within-subject associations between co-occurring OCS and symptom cluster of psychosis. Differences on these two levels suggest different underlying mechanisms. The association between depressive symptoms and subsequent increase/decrease of OCS within patients may have important treatment implications. [ABSTRACT FROM AUTHOR]

There is a strong push for the inclusion of effect size indexes alongside the reporting of statistical analysis in academic journals. Nonparametric methods of analysis have generally been developed less than their parametric counterparts have, and are also generally less well known. Too often researchers use parametric statistics where nonparametric measures would be more appropriate. This holds true for nonparametric measures of effect size, where even when researchers use nonparametric statistics, some use parametric effect size measures to interpret the result. This paper attempts to provide a practical overview and illustration of the correct usage and interpretation of effect size measures for nonparametric statistics for single study designs using real-world physiotherapy data in the worked examples. This primer covers a range of different formulae based on categorical measures of effect size, as well as between- and within-group designs using ranked data. While this primer does use examples focusing on physiotherapy research, the applications of the information can be used in any field of research. [ABSTRACT FROM AUTHOR]

Ego depletion is under scrutiny for low replicability, possibly reflecting the limited statistical power available in between-subject designs. In response, we created a within-subject, repeated-measures ego-depletion paradigm that repeatedly alternated depletion and recovery manipulations. Each manipulation was followed by measuring subjective fatigue, mood, and self-control performance. Across 12 studies (N = 754), participants reliably reported having lower energy and mood after depleting manipulations compared to after recovery manipulations. Depletion manipulations did not consistently affect behavioral self-control, although the depletion effect was meta-analytically significant (d = .045). Furthermore, unintended fatigue and practice effects occurred over the course of the paradigm, systematically interfering with the intended depletion effects. We recommend that depletion research takes advantage of within-subject designs across multiple sessions to avoid spillover effects between measurements. [ABSTRACT FROM AUTHOR]

Growth developmental research is one example of the application of longitudinal data that have correlated value over time. Linear Mixed Model (LMM) is an extension of classic statistical procedures that provides flexibility analysis in correlated longitudinal data and allows researcher to model the covariance structures that represent its random effects. This paper briefly describes growth curves model as a single LMM that represent two levels of observation, which focused on modeling its covariance structure to capture correlated information over time of individual performance. We apply LMM and model different types of its covariance structure in the simulation study of children’s growth differences based on the feeding methods. We perform simulation scenario using MIXED procedure in SAS system, based on three fit indices (-2RLL, AIC and SBC) and p -value significance level, we obtain Unstructured (UN) covariance is always be the best fit in presenting the characteristic of data but not the best choice considering inefficient numbers of parameters while Heterogeneous First-order Autoregressive (ARH(1)) is a proper alternative covariance structure with ease of data interpretation from fewer numbers of estimated parameters. [ABSTRACT FROM AUTHOR]

Background: High average (VALR) and instantaneous vertical loading rates (VILR) during impact have been associated with many running-related injuries. Peak acceleration (PA), measured with an accelerometer, has provided an alternative method to estimate impact loading during outdoor running. This study sought to compare both intra- and inter-subject correlations between vertical loading rates and PA measured at two body sites during running.Methods: Ground reaction force data were collected from 10 healthy adults (age=23.6±3.8 years) during treadmill running at different speeds and inclination surfaces. Concurrently, PAs at the lateral malleoli and the distal tibia were measured using synchronized accelerometers.Results: We found significant positive intra-subject correlation between loading rates and PA at the lateral malleoli (r=0.561-0.950, p<0.001) and the distal tibia (r=0.486-0.913, p<0.001). PA measured at the lateral malleoli showed stronger correlation with loading rates (p=0.004) than the measurement at the distal tibia. On the other hand, inter-subject variances were observed in the association between PA and vertical loading rates. The inter-subject variances at the distal tibia were 3.88±3.09BW/s and 5.69±3.05BW/s in VALR and VLIR respectively. Similarly, the inter-subject variances in the measurement at lateral malleoli were 5.24±2.85BW/s and 6.67±2.83BW/s in VALR and VLIR respectively.Conclusions: PA measured at lateral malleoli has stronger correlation with VALR or VILR than the measurement at distal tibia. Caution is advised when using PA to conduct inter-subject comparisons of vertical loading rates during running. [ABSTRACT FROM AUTHOR]

Background: Randomized controlled trials are the sine qua non of causal inference; however, heterogeneity of treatment effects for many chronic conditions and for many symptoms often limits their utility. Single-patient studies in which patients select a treatment after trying a randomized sequence of treatments (i.e., multiple crossover trials) offer an alternative to traditional randomized controlled trials by providing scientifically valid results in a practical manner that can be used by patients and their providers to decide upon their personally optimal treatment. Although N-of-1 trials have been used in the medical literature, their use for interventions that consist of psychological or health behavior outcomes is unknown. This systematic review thus aims to describe the interventions and outcomes and assess the quality of N-of-1 trials for psychological or health behavior outcomes. Methods/Design: Electronic databases (Ovid MEDLINE, EMBASE, CINAHL, PsycINFO, and the six databases in the Cochrane Library) will be searched using all relevant subject headings and free-text terms to represent N-of-1 trials and psychological or behavioral interventions. Full text review and bibliography searching will be conducted. Unpublished studies will be sought by searching trial registries and contacting authors of included studies. Eligibility criteria are the following: population, all human participants for whom N-of-1 trials with psychological or health behavior outcomes have been conducted; interventions, all interventions for which N-of-1 trials have been conducted; comparison, placebo or active treatment control; and outcome, psychological and health behavior outcomes including self-perceived disease severity and psychological phenomena such as mood and affect. Studies that do not contain sufficient trial detail, describe only design or statistical analytic issues in N-of-1 trials without presentation of an N-of-1 trial itself, and/or are not written in the English language are ineligible. Screening, data extraction, and quality assessment will be conducted by two independent reviewers with disagreements resolved through discussion. Discussion: This systematic review will describe the interventions and outcomes and assess the quality of N-of-1 trials for psychological or health behavior outcomes. The results will clarify the use of this research methodology in the health psychology and behavioral medicine literature and may pave the way for additional N-of-1 trials to be conducted. [ABSTRACT FROM AUTHOR]

Notwithstanding a recent flurry of organizational research on the construct of “situational strength,” research on the other side of the coin—“personality strength”—has rarely been conducted in organizational settings, has been scattered across multiple disciplines, has been called different things by different researchers, and has not yet been used to test theoretical propositions paralleling those in recent organizational research on situational strength. In the present review, drawing from several disparate research literatures (e.g., situational strength, personality states, traitedness, cross-situational consistency, scalability, appropriateness, self-monitoring, interpersonal dependency, hardiness, attitude strength, and self-concept clarity), we (a) define personality strength and contrast it with personality trait, personality strengths (plural), and layperson conceptualizations of the terms “strong personality” and “weak personality,” (b) briefly discuss the history of research related to personality strength, (c) identify a common prediction, emanating largely independently from several literatures, regarding the interactive effect of personality traits and personality strength on behavior, (d) articulate three novel predictions regarding the impact of personality strength on within-person situational and behavioral variability, (e) develop three broad categories of personality strength operationalizations (i.e., statistical, content-general, and content-independent) and discuss potential interrelationships among them, (f) suggest “best practices” for operationalization, thereby providing an agenda for future research, and, finally, (g) discuss the practical implications of this work for human resource management. [ABSTRACT FROM PUBLISHER]

The purpose of this paper was to establish the variability and typical error of kinematic and kinetic variables representing the maximal instep kick in soccer for both the kicking and support legs. Ten skilled (good amateur or semi-professional) soccer players performed 20 maximal instep kicks of a stationary ball into a goal mouth. Motion of the kicking and support legs was recorded by an optoelectronic motion analysis system, and a six degrees of freedom model was used to compute kinematic and kinetic variables. Participants repeated the kicks on a second day at least 1 week later. The mean within-subject coefficient of variation across the kinematic and kinetic variables, trials, and days was 16% and did not change substantially as trial number increased or between day of test. Increasing trial number reduced the typical error (as determined by the standard error of the mean) such that for 20 trials 75% of the variables were below an arbitrary 5% threshold. It was concluded that for kicking investigations, 10–15 trials could be used and typical errors of 5% should be expected. [ABSTRACT FROM PUBLISHER]

Most Americans now live together before they marry but little is known about how the transition from dating to cohabiting affects relationships. In two studies, we compared dating and cohabiting relationships in terms of commitment and several indices of relationship quality. In Study 1, we used a nationally representative sample of 1,294 unmarried individuals in opposite sex relationships who completed surveys by mail. Findings showed that cohabiting relationships were characterized by more commitment, lower satisfaction, more negative communication, and more physical aggression than dating (noncohabiting) relationships; controlling for selection factors mitigated some of these differences. Study 2 used a subsample of the Study 1 sample to longitudinally examine how transitioning from dating to cohabiting changes a relationship on the same dimensions. Six waves of mailed surveys spanning 20 months were employed. Findings of Study 2 indicated that individuals experienced declines in most indices of relationship quality as well as in interpersonal commitment after cohabitation began, though the frequency of sex increased temporarily. Constraints to stay together substantially increased with cohabitation and over time. Implications of these findings for future research are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Oxytocin is important to social behavior and emotion regulation in humans. Oxytocin''s role derives in part from its effect on memory performance. More specifically, previous research suggests that oxytocin facilitates recognition of social (e.g., faces), but not of non-social stimuli (e.g., words, visual objects). We conducted the first within-subject study to this hypothesis in a double-blind, placebo-controlled design. We administered oxytocin (24IU) and placebo (saline) in two separate sessions and in randomized order to healthy men. To obtain a baseline measure for session-dependent memory effects, which are caused by proactive interference, an additional group of male subjects in each session received placebo unbeknownst to them and the experimenter. After administration, participants studied faces and houses. Exactly one day after each study session, participants were asked to make memory judgments of new and old items. In the first study–test session, participants administered with oxytocin showed reduced recollection of previously studied faces and houses. Oxytocin also interacted with proactive-interference effects. By impeding memory in the first session, it reduced proactive interference in the second. But oxytocin contributed additionally to the memory-reducing effect of proactive interference when administered in the second session. These results demonstrate that oxytocin can have a memory-impairing effect on both social and non-social visual objects. The present study also emphasizes the necessity of including a non-treated, baseline group in within-subject designs when investigating oxytocin''s effects on human memory. [Copyright &y& Elsevier]

Abstract: In this article we explore the issues that surround within-subject and between-subject designs. We describe experiments in economics and in psychology that make comparisons using either of these designs (or both) that sometimes yield the same results and sometimes do not. The overall goal is to establish a framework for understanding which critical questions need to be asked about such experimental studies, what authors of such studies can do to ameliorate fears of confoundedness, and which scenarios are particularly susceptible to divergent results from the two approaches. Overall, we find that both designs have their merits, and the choice of designs should be carefully considered in the context of the question being studied and in terms of the practical implementation of the research study. [Copyright &y& Elsevier]

Abstract: The Morris water maze is a commonly employed method to investigate learning and memory. The task demands experimental subjects use distal spatial cues in navigating to a hidden escape platform while swimming in a pool of opaque water. Since its primary description thirty years ago, several modifications have emerged. For example, part-way through the experiment, the target platform can be re-located, thus requiring subjects re-learn spatial aspects of the task. This procedure demands sequential memory encoding of highly similar events and can be selectively impaired by genetic and pharmacological methods affecting cognitive flexibility. While the primary reasons for employing re-locating platform tasks are to study aspects of cognitive flexibility, the paradigms also demonstrate a potential for reducing within-treatment group variation by enabling within-subject analysis. We tested this hypothesis using the C57BL/6 mouse line, a commonly chosen subject for behavioral experiments, and demonstrate that a within-subject comparison approach is both valid and effective in reducing variability. Interestingly, the within-subject statistical advantage is most pronounced for performance measures of short-term memory. In addition, we find that subject naivety, but not experimental inter-phase interval or subcutaneous saline injections, has a significant effect on variation in performance. We also found repeated training in the Morris water maze improved short-term memory without enhancing long-term memory. Together, the data suggest platform re-location tasks can help alleviate within-group variability, a major conundrum in behavioral neuroscience, and provide valuable insight into the general sources of variability underlying performance in cognitive tasks. [Copyright &y& Elsevier]

Just as chemistry has methods for determining the composition of unknown substances, psychology needs, but has lacked, effective methods for identifying the 'active ingredients' of social stimuli. We describe such a method and apply it to identify the verbal and nonverbal distress cues that serve as signals prompting others to provide social support. This method allowed us to identify 55 such cues. Furthermore, the cues that were salient in the minds of potential support providers depended on their goals. For example, when deciding whether someone needed support, negative nonverbal cues (e.g., distressed persons' fidgeting) were more salient, but when deciding whether one was willing to provide support, cues that suggested a positive outcome for the support seeker (e.g., distressed persons' positive attitude and open-mindedness) were more salient. [ABSTRACT FROM AUTHOR]

Abstract: Previous laboratory studies have reported that moderate caffeine consumers develop a liking for the flavour of a novel caffeinated drink. The present study tested whether results from laboratory studies are applicable to real-life situations. Forty moderate caffeine consumers were randomly allocated to four conditions (n =10). Three of these conditions involved consumption of two novel flavoured fruit drinks, one caffeinated (100mg) and one without caffeine, at different times of the participants’ daily routine (breakfast, anytime, night). Participants in the final (control) condition evaluated the drinks on the three test days only. Those participants who received the drinks at breakfast showed a significant increase in liking for the flavour of the caffeinated drink, whereas those who consumed the drinks at night showed a significant decrease in liking for the same flavour. Results imply that the post-ingestive effect of caffeine may depend on the time and condition during which the caffeinated flavour is consumed. [Copyright &y& Elsevier]

Objective: Circulating glucose may relate to affective and physical feeling states reflective of emotional disorder symptoms. No prior studies have investigated within-day associations between glucose and subsequent affective and physical feeling states (positive affect, negative affect, and fatigue) as they occur naturally among healthy adolescents; this pilot study assessed these associations by combining data collected from ecological momentary assessment (EMA) and continuous glucose monitors (CGM).Methods: Participants (N = 15, mean age = 13.1[±1.0] years, 66.7% female, 40.0% Hispanic, 66.7% healthy weight) wore a CGM for 7-14 days. Simultaneously, participants reported on their current positive affect, negative affect, and fatigue randomly during specified windows up to 7 times daily via EMA. CGM-measured mean interstitial glucose was calculated during the time windows (mean minutes = 122.5[±47.3]) leading up to each EMA prompt. Multilevel models assessed within-subject (WS) associations between mean interstitial glucose since the previous EMA prompt and EMA-reported affective and physical feeling states at the current prompt.Results: Participants provided 532 interstitial glucose-matched EMA reports of affective and physical feeling states. During intervals when interstitial glucose was higher than one's usual, higher positive affect (WS β = 0.01, p < .0001, f2 = 0.02) and lower fatigue (WS β = -0.01, p < .0001, f2 = 0.09) were subsequently reported. Interstitial glucose was unrelated to negative affect (WS β = -0.002, p = .10, f2 = 0.01). Associations were weakened, but remained significant following further adjustment for time of day.Conclusions: Though effect sizes were small, within-person variations in interstitial glucose may relate to subsequent affective and physical feeling states among healthy youth. Investigations using similar methodologies in larger, more diverse samples are warranted. [ABSTRACT FROM AUTHOR]

Introduction: Acceptance & Commitment Therapy (ACT) explicitly postulates experiential avoidance (EA) and values-based living (VBL) as essential treatment processes. As outcomes from between-subject studies cannot readily be generalized to within-subject processes in individuals, we explored the unfolding of, and relationship between, EA and VBL and levels of pain interference in daily life and emotional well-being within individuals experiencing chronic pain., Methods: Using n- of-1 designs, three participants following a multidisciplinary treatment program filled out a 12-item daily questionnaire (87-110 days). After multiple imputation of missing data, McKnight Time-series analysis procedures were performed for each participant separately. The interrelationships of EA, VBL and pain intensity, and the relationship of EA and VBL beyond pain intensity with both chronic pain outcomes were assessed both concurrently (same day) and prospectively (consecutive days)., Results: Both EA and VBL were associated with at least one of five outcome variables (four domains of pain interference and emotional well-being) beyond pain intensity in two participants, but not in the third participant. These associations primarily existed for concurrent, but not consecutive, days. In contrast to VBL, EA was not associated with emotional well-being for any of the three participants., Conclusions: Although the finding that ACT-processes were associated with pain outcomes on concurrent days is consistent with ACT theory, the absence of such associations on consecutive days means that alternative explanations cannot be rule out. One possibility is that pain interference fluctuates within days at a higher variability rate than was currently assessed. Future research should consider using a higher measurement frequency to be able to grasp time-lagged effects., Competing Interests: The authors declare that there is no conflict of interest., (© Person-Oriented Research.)

Recently several novel image contrasts derived from whole-brain fibre tracking-data (tractograms) have been introduced. The novel contrasts of these track-weighted imaging (TWI) methods may provide important information for clinical neuroscience studies. However, before they can be used reliably to generate quantitative measures, it is important to characterise their within-subject reproducibility, and between-subject variability. In this work we compute the within-subject reproducibility (intra-scan, intra-session and inter-session), and between-subject variability of TWI for a number of different TWI contrasts across multiple subjects. The results are used in simple voxel-wise power calculations within illustrative regions of interest to provide guidelines for required sample sizes and observable effect sizes for individual subjects and between groups. It was found that the required sample sizes and observable effect sizes varied considerably between different TWI maps and for different ROIs. For some TWI contrast and ROI combinations, the power calculations yielded clinically practical values. These results provide important information concerning the potential usefulness and sensitivity of TWI maps for individual diagnosis, longitudinal studies and group comparisons, as well as for study designs., (Copyright © 2013 Elsevier Inc. All rights reserved.)