Prior exposure to a sensorimotor game in virtual reality does not enhance stress reactivity toward the OpenTSST VR.

Compared to the in-person Trier Social Stress Test (TSST), virtual reality (VR) variants reduce resource-intensity and improve standardization but induce stress with smaller effect sizes. However, higher cortisol reactivity is given for more immersive TSST-VRs. Immersivity depends on the VR-system, but perceived immersion may be targeted by exposure to, or interaction with the VR. We investigated whether stress reactivity towards the openly accessible OpenTSST VR can be enhanced by prior exposure to a sensorimotor game completed in VR as mediated by increased immersion. Therefore, N = 58 healthy participants underwent the OpenTSST VR or its inbuilt control condition (placebo TSST-VR, pTSST-VR). Beforehand, participants completed a sensorimotor game either in VR or in real life. Stress was measured by means of self-reports, salivary cortisol concentrations, and salivary alpha-amylase (sAA) activity. Perceived immersion was assessed with the Igroup Presence Questionnaire (IPQ). The TSST-VR-group showed higher subjective stress than the pTSST-VR-group. Even though area under the curve measures indicated significant differences in cortisol levels between TSST-VR and pTSST-VR, this effect was not replicated in omnibus-analyses. Likewise, sAA was not responsive to stress. Our data suggests the OpenTSST VR does not reliably trigger physiological stress reactivity. Likewise, participants playing the VR-game before exposure to the TSST-VR did not show enhanced stress reactivity. Importantly, playing the VR-game did not lead to increased immersion (indicated by the IPQ), either. The key question resulting from our study is which manipulation may be fruitful to obtain a comparable stress response toward the TSST-VR compared to the in-person TSST.

TSST-OL: Comparison between online and laboratory application and effects on empathy.

Online test protocols are increasingly popular in psychological and neuroscientific research. Despite its relevance to the social functioning, the influence of acute stress on cognitive and affective state empathy is not clearly understood. Recently, a remote online version (TSST-OL) of the Trier Social Stress Test (TSST) was established for use in research with both children and adults. In general, the TSST-OL offers the opportunity for context-independent application (e.g., at the participants' home or in field contexts). However, in order to exploit this opportunity, it seems crucial to validate the TSST-OL across different settings and contextual variables. We compared stress reactivity in response to the TSST-OL at home and in the laboratory. In a 2 ×2 factorial design, N=120 participants (n=60 women) underwent the TSST-OL and an online adaption of the friendly TSST (fTSST-OL) either at home (n=60) or at the laboratory (n=60). Stress induction was evaluated in terms of physiological (cortisol and salivary alpha-amylase, sAA) and subjective stress and affect measures. Participants also completed an empathy performance task after stress and control exposure. Results confirmed that the TSST-OL successfully induced stress both when conducted at participants' homes and in the laboratory. Still, cortisol levels were higher during laboratory participation compared to application at home, likely due to anticipatory stress. Consequently, the TSST-OL in a home-based application seems to buffer anticipatory stress thus making it an attractive tool to study experimentally induced stress reactivity. Concerning empathy, positive emotions were generally better identified (cognitive empathy) and empathized (affective empathy) than negative emotions. For the latter, this difference was absent after stress, indicated by decreased affective empathy for positive emotions. Overall, this study indicates that the TSST-OL induces stress and validates the tool using a rigorous study design with sufficient participants and relevant stress parameters. Thus, future studies may apply the TSST-OL in different contexts and diverse samples. The findings on empathy under stress align with mixed results in existing research, highlighting the necessity for further investigations into empathy, considering various measurements, stimulus valence, and sex of the participant.

Using the online version of the Trier Social Stress Test to investigate the effect of acute stress on functional lateralization.

How stress affects functional hemispheric asymmetries is relevant because stress represents a risk factor for the development of mental disorders and various mental disorders are associated with atypical lateralization. Using three lateralization tasks, we investigated whether functional hemispheric asymmetries in the form of hemispheric dominance for language (verbal dichotic listening task), emotion processing (emotional dichotic listening task), and visuo-spatial attention (line bisection task) were affected by acute stress in healthy adults. One hundred twenty right-handed men and women performed these lateralization tasks in randomized order after exposure to a mild online stressor (i.e., an online variant of the Trier Social Stress Test (TSST), TSST-OL) and a non-stressful online control task (friendly TSST-OL, fTSST-OL) in a within-subjects design. Importantly, the verbal and the emotional dichotic listening tasks were presented online whereas the line bisection task was completed in paper-pencil form. During these tasks, we found the expected hemispheric asymmetries, indicating that online versions of both the verbal and the emotional dichotic listening task can be used to measure functional hemispheric asymmetries in language and emotion processing remotely. Even though subjective and physiological markers confirmed the success of the online stress manipulation, replicating previous studies, we found no stress-induced effect on functional hemispheric asymmetries. Thus, in healthy participants, functional hemispheric asymmetries do not seem to change flexibly in response to acute stress.

Stability and durability of salivary alpha-amylase across different storage conditions.

Data collection in remote and field settings gains importance and popularity in stress research. Accordingly, existing stress induction paradigms have been successfully adapted to remote and field settings. However, guidelines for the comprehensive assessment of biomarkers such as salivary alpha-amylase (sAA) have yet to be sufficiently established for such contexts. In remote and field settings, swift freezing of saliva samples is not always possible, and samples must be returned to the laboratory for further processing. The current study investigated the robustness of sAA activity against external factors that may affect measurements obtained from saliva samples collected in field and remote settings. We compared sAA activity of samples that were stored in different vials (Salivettes® and Eppendorf® vials) and that were exposed to (1) up to three cycles of freezing and thawing, (2) different temperatures (4 °C, 20 °C, 30 °C, and 40 °C) for 3, 7, 14, or 28 days, or that were (3) sent via postal delivery. Results indicate sAA activity to be susceptible across different temperatures, different time intervals, and different vials. As a systematic pattern, sAA activity seems to decrease in treated samples with this effect being potentiated by more extreme conditions such as higher temperatures and longer time intervals. To conclude, sAA data collected in remote or field settings could be affected systematically by various external variables. Future studies collecting sAA should take factors influencing the durability and stability of sAA into account to ensure reliable and valid measurements of salivary data.

A deep phenotyping approach to assess the association of handedness, early life factors and mental health.

The development of handedness and other form of functional asymmetries is not yet understood in its critical determinants. Early life factors (e.g., birth weight, birth order) have been discussed to contribute to individual manifestations of functional asymmetries. However, large-scale data such as the UK Biobank suggest that the variance in handedness that is explained by early life factors is minimal. Additionally, atypical handedness has been linked to clinical outcomes such as neurodevelopmental and psychiatric disorders. Against the background of this triad, the current study investigated associations between different forms of functional asymmetries and (a) early life factors as well as (b) clinical outcomes. Functional asymmetries were determined by means of a deep phenotyping approach which notably extends previous work. In our final sample of N = 598 healthy participants, the different variables were tested for associations by means of linear regression models and group comparisons (i.e., ANOVAs and Chi-squared tests). Confirming previous findings from larger cohorts with shallow phenotyping, we found that birth factors do not explain a substantial amount of variance in functional asymmetries. Likewise, functional asymmetries did not seem to have comprehensive predictive power concerning clinical outcomes in our healthy participants. Future studies may further investigate postulated relations in healthy and clinical samples while acknowledging deep phenotyping of laterality.

Handedness in twins: meta-analyses.

BACKGROUND: In the general population, 10.6% of people favor their left hand over the right for motor tasks. Previous research suggests higher prevalence of atypical (left-, mixed-, or non-right-) handedness in (i) twins compared to singletons, and in (ii) monozygotic compared to dizygotic twins. Moreover, (iii) studies have shown a higher rate of handedness concordance in monozygotic compared to dizygotic twins, in line with genetic factors playing a role for handedness. METHODS: By means of a systematic review, we identified 59 studies from previous literature and performed three sets of random effects meta-analyses on (i) twin-to-singleton Odds Ratios (21 studies, n = 189,422 individuals) and (ii) monozygotic-to-dizygotic twin Odds Ratios (48 studies, n = 63,295 individuals), both times for prevalence of left-, mixed-, and non-right-handedness. For monozygotic and dizygotic twin pairs we compared (iii) handedness concordance Odds Ratios (44 studies, n = 36,217 twin pairs). We also tested for potential effects of moderating variables, such as sex, age, the method used to assess handedness, and the twins' zygosity. RESULTS: We found (i) evidence for higher prevalence of left- (Odds Ratio = 1.40, 95% Confidence Interval = [1.26, 1.57]) and non-right- (Odds Ratio = 1.36, 95% Confidence Interval = [1.22, 1.52]), but not mixed-handedness (Odds Ratio = 1.08, 95% Confidence Interval = [0.52, 2.27]) among twins compared to singletons. We further showed a decrease in Odds Ratios in more recent studies (post-1975: Odds Ratio = 1.30, 95% Confidence Interval = [1.17, 1.45]) compared to earlier studies (pre-1975: Odds Ratio = 1.90, 95% Confidence Interval = [1.59-2.27]). While there was (ii) no difference between monozygotic and dizygotic twins regarding prevalence of left- (Odds Ratio = 0.98, 95% Confidence Interval = [0.89, 1.07]), mixed- (Odds Ratio = 0.96, 95% Confidence Interval = [0.46, 1.99]), or non-right-handedness (Odds Ratio = 1.01, 95% Confidence Interval = [0.91, 1.12]), we found that (iii) handedness concordance was elevated among monozygotic compared to dizygotic twin pairs (Odds Ratio = 1.11, 95% Confidence Interval = [1.06, 1.18]). By means of moderator analyses, we did not find evidence for effects of potentially confounding variables. CONCLUSION: We provide the largest and most comprehensive meta-analysis on handedness in twins. Although a raw, unadjusted analysis found a higher prevalence of left- and non-right-, but not mixed-handedness among twins compared to singletons, left-handedness was substantially more prevalent in earlier than in more recent studies. The single large, recent study which included birth weight, Apgar score and gestational age as covariates found no twin-singleton difference in handedness rate, but these covariates could not be included in the present meta-analysis. Together, the secular shift and the influence of covariates probably make it unsafe to conclude that twinning has a genuine relationship to handedness.

Stress research during the COVID-19 pandemic and beyond.

The COVID-19 pandemic confronts stress researchers in psychology and neuroscience with unique challenges. Widely used experimental paradigms such as the Trier Social Stress Test feature physical social encounters to induce stress by means of social-evaluative threat. As lockdowns and contact restrictions currently prevent in-person meetings, established stress induction paradigms are often difficult to use. Despite these challenges, stress research is of pivotal importance as the pandemic will likely increase the prevalence of stress-related mental disorders. Therefore, we review recent research trends like virtual reality, pre-recordings and online adaptations regarding their usefulness for established stress induction paradigms. Such approaches are not only crucial for stress research during COVID-19 but will likely stimulate the field far beyond the pandemic. They may facilitate research in new contexts and in homebound or movement-restricted participant groups. Moreover, they allow for new experimental variations that may advance procedures as well as the conceptualization of stress itself. While posing challenges for stress researchers undeniably, the COVID-19 pandemic may evolve into a driving force for progress eventually.

Handedness and depression: A meta-analysis across 87 studies.

Alterations in functional brain lateralization, often indicated by an increased prevalence of left- and/or mixed-handedness, have been demonstrated in several psychiatric and neurodevelopmental disorders like schizophrenia or autism spectrum disorder. For depression, however, this relationship is largely unclear. While a few studies found evidence that handedness and depression are associated, both the effect size and the direction of this association remain elusive. Here, we collected data from 87 studies totaling 35,501 individuals to provide a precise estimate of differences in left-, mixed- and non-right-handedness between depressed and healthy samples and computed odds ratios (ORs) between these groups. Here, an OR > 1 signifies higher rates of atypical handedness in depressed compared to healthy samples. We found no differences in left- (OR = 1.04, 95% CI = [0.95, 1.15], p = .384), mixed- (OR = 1.64, 95% CI = [0.98, 2.74], p = .060) or non-right-handedness (OR = 1.05, 95% CI = [0.96, 1.15], p = .309) between the two groups. We could thus find no link between handedness and depression on the meta-analytical level.