Stress Task Research Articles

Implications of respiratory sinus arrhythmia (RSA) inertia for child psychopathology: Direct effect and interaction with between-task RSA reactivity.

Respiratory sinus arrhythmia (RSA) inertia is the temporary dependency of RSA levels between consecutive epochs, which captures the epoch-to-epoch stickiness of RSA reactivity. Previous studies examining the developmental function of between-task RSA reactivity have yielded mixed findings and have often overlooked RSA reactivity within the task. The present study examined whether RSA inertia during a stress task was associated with subsequent changes in child psychopathology symptoms. To have a comprehensive understanding of the function of RSA reactivity, we tested whether RSA inertia interacted with between-task RSA reactivity to jointly predict changes in child psychopathology symptoms. Eighty-nine middle-to-high income Chinese parent-child dyads were recruited. Children (Mage = 8.77 years, SD = 1.80 years, 41 girls) participated in a 2-min resting phase and then a 4-min stress task (a public speaking task), during which RSA was continuously recorded in the lab. Parents (Mage = 39.27 years, SD = 3.53 years, 67 mothers) reported on children's psychopathology symptoms in the lab and again 9 months later. Children with heightened RSA inertia tended to exhibit increased externalizing symptoms 9 months later. Moreover, RSA inertia interacted with between-task RSA reactivity to predict subsequent changes in externalizing symptoms. Children with the combination of lower RSA inertia and larger between-task RSA decreases had the lowest externalizing symptoms, suggesting an adaptive RSA reactivity pattern. Heightened within-task RSA inertia as well as reduced between-task RSA reactivity may help to identify children at risk for subsequent psychopathology symptoms, aiding in early intervention efforts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Beat-to-beat analysis of hemodynamic response to mental and psychological stress in sickle cell anemia

Abstract Vaso-occlusive crises are a hallmark symptom of sickle cell disease. Physical stressors can trigger decreased microvascular blood flow and increase the risk for vaso-occlusive crises. However, the effect of mental and psychological stressors on vascular physiology in sickle cell disease is not well-established. We hereby examined fluctuations in continuous blood pressure to evaluate hemodynamic changes in sickle cell disease patients during mental and psychological stress. Thirteen sickle cell disease subjects from the Children’s Hospital Los Angeles and 11 healthy volunteers were recruited. Continuous blood pressure was recorded during two mental tasks and one psychological stress task. Systolic beat-to-beat blood pressure variability measurements were calculated for each subject. Three very short-term blood pressure variability metrics served as outcome measures: standard deviation, coefficient of variation, and average real variability. Peripheral augmentation index was calculated from arterial waveforms. Linear mixed effects models evaluated associations between patient factors and outcome measures. Sickle cell disease patients exhibit increased systolic blood pressure variability in response to psychological stress. All subjects exhibited a decrease in systolic blood pressure variability in response to mental stress tasks. During mental stress, both groups displayed increased augmentation index, reflective of stress-induced vasoconstriction, while psychological stress in sickle cell disease patients led to both decreased mean arterial pressure and increased augementation index, suggestive of uncompensated vasoconstriction. These findings emphasize the impact of mental and psychological stressors on vascular function in sickle cell disease and the potential for monitoring physiological signals to predict vaso-occlusive crisis events.

Prior exposure to racial discrimination and patterns of acute parasympathetic nervous system responses to a race-related stress task among Black adults.

Black adults' prior exposure to racial discrimination may be associated with their acute parasympathetic reactivity to and recovery from a new race-related stressor. Existing analytical approaches to investigating this link obscure nuances in the timing, magnitude, and patterns of these acute parasympathetic nervous system (PNS) responses. In a re-analysis of a prior study, we utilize an hidden Markov model (HMM) approach to examine how prior experiences of racial discrimination are associated with intraindividual patterns of (1) physiological states of PNS activity and (2) patterns of and variability in transitions between these physiological states. Participants (N = 118) were Black young adults (range 18-29 years; Mage = 19.67, SDage = 2.04) who completed an online survey to index prior racial discrimination exposure, followed by an in-person lab visit during which their PNS activity in response to a race-related stress task was measured via electrocardiogram and converted into respiratory sinus arrhythmia. HMMs indicated evidence for two states: baseline and a second state representing a significant reduction in respiratory sinus arrhythmia. Most participants (93.22%) demonstrated a blunted response to the task, indicating that they did not transition from baseline during the procedure. Prior racial discrimination was not associated with HMM states or state transition parameters. Blunted physiological responses may be an important area of future investigation that could inform early life course mental and physical health screenings.

Patterns of stress-related change in salivary alpha-amylase and cortisol among young children: Associations with maternal psychosocial risk factors

Our understanding of associations between family-level risk factors and children’s stress physiology is largely derived from studies that apply “mean-based” rather than “person-level” approaches. In this study, we employed group-based trajectory modeling, a person-centered approach, to identify children with similar patterns of stress-related sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis activation, and explored associations between these patterns and maternal psychosocial risk. Participants were five-year-old children (N=147; 52 % female; 62 % Black/African American) and their mothers. Children’s saliva was sampled four times during a series of emotional stressor tasks and later assayed for sAA and cortisol, indexing SNS and HPA activity, respectively. Mothers reported their depressive and anxiety symptoms, parenting stress, financial stress, and income. Results revealed two task-related patterns of change for sAA (Low-Stable vs. High-Increasing) and cortisol (Low-Stable vs. High-Decreasing) concentrations. Children from families with lower income were more likely to exhibit the High-Increasing SNS pattern, [OR=0.78, 95 % CI (0.64, 0.95)], and children of mothers reporting more anxiety symptoms [OR=1.06, 95 % CI (1.00, 1.12)] and more parenting stress [OR=1.04, 95 % CI (1.00, 1.07)] were more likely to show the High-Decreasing HPA pattern. Implications of this person-centered approach and findings for advancing our understanding of associations between family-level risk factors and children’s stress physiology are discussed.

The cardiac, vasomotor and myocardial branches of the baroreflex in hypotension: indications of reduced venous return to the heart.

Alterations of autonomic cardiovascular control are implicated in the origin of chronic low blood pressure (BP) (hypotension), but comprehensive analysis of baroreflex function is still lacking. This study explored baroreflex function in its cardiac, vascular and myocardial branches METHODS: Continuous BP was recorded at rest and during a mental arithmetic task in 40 hypotensive and 40 normotensive participants. Assessed cardiovascular variables included stroke volume (SV) (calculated by the Modelflow method), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and heart rate variability (HRV). Baroreflex sensitivity (BRS) was calculated using the spontaneous sequence method. Hypotensive participants exhibited greater BRS in the three baroreflex branches, in addition to lower SV, HR and CO and higher HRV and TPR. Reactivity for BP, HRV and CO during the stress task was reduced in hypotensive individuals. The greater cardiac BRS can explain the lower HR and higher HRV observed in hypotension, suggestive of increased vagal cardiac influences. The higher vasomotor BRS may contribute to the greater TPR observed in the hypotensive participants. Abnormal associations between myocardial BRS and SV arose, suggesting aberrant autonomic control of myocardial contractility in hypotension. The results indicate that hemodynamic deficits in hypotension are related to preload factors, probably triggered by hypovolemia and reduced unstressed blood reserves, resulting in lower venous return, ventricular preload and SV. In contrast, afterload mechanisms seem to work appropriately.

Negative auditory hallucinations are associated with increased activation of the defensive motivational system in schizophrenia

Auditory hallucinations (AH) are the most common symptom of psychosis. The voices people hear make comments that are benign or even encouraging, but most often voices are threatening and derogatory. Negative AH are often highly distressing and contribute to suicide risk and violent behavior. Biological mechanisms underlying the valence of voices (i.e., positive, negative, neutral) are not well delineated. In the current study, we examined whether AH voice valence was associated with increased activation of the Defensive Motivational System, as indexed by central and autonomic system response to unpleasant stimuli. Data were evaluated from two studies that used a common symptom rating instrument, the Psychotic Symptom Rating Scale (PSY-RATS), to measure AH valence. Participants included outpatients diagnosed with SZ. Tasks included: Study 1: Trier Social Stress Task while heart rate was recorded via electrocardiography (N = 27); Study 2: Passive Viewing Task while participants were exposed to pleasant, unpleasant, and neutral images from the International Affective Picture System (IAPS) library while eye movements, pupil dilation, and electroencephalography were recorded (N = 25). Results indicated that negative voice content was significantly associated with: 1) increased heart rate during an acute social stressor, 2) increased pupil dilation to unpleasant images, 3) higher neural reactivity to unpleasant images, and 4) a greater likelihood of having bottom-up attention drawn to unpleasant stimuli. Findings suggest that negative AH are associated with greater Defensive Motivational System activation in terms of central and autonomic nervous system response.

The impact of cannabidiol placebo on amygdala-based neural responses to an acute stressor.

Cannabidiol (CBD) impacts brain regions implicated in anxiety reactivity and stress reactivity (e.g., amygdala, anterior cingulate cortex (ACC), anterior insula (AI)); however, placebo-controlled studies are mixed regarding CBD's anxiolytic effects. We previously reported that CBD expectancy alone can alter subjective, physiological, and endocrine markers of stress/anxiety; however, it is unclear whether these findings reflect altered brain reactivity. This study evaluated whether CBD expectancy independently alters amygdala resting-state functional connectivity (rsFC) with the ACC and AI following acute stress. Thirty-eight (20 females) healthy adults were randomly assigned to receive accurate or inaccurate information regarding the CBD content of a CBD-free oil administered during a single experimental session. Following a baseline resting state MRI scan, participants administered their assigned oil sublingually, engaged in a stress task (serial subtraction with negative feedback) inside the scanner, and underwent another resting state MRI scan. Amygdala rsFC with the ACC and AI was measured during each scan, and the subjective state was assessed at six time points. Outcomes were analyzed using ANCOVA. CBD expectancy (vs CBD-free expectancy) was associated with significantly weaker rsFC between the left amygdala and right ACC (p = 0.042), but did not systematically alter amygdala-AI rsFC (p-values > 0.05). We also replicated our previously reported CBD expectancy effects on subjective stress/anxiety in the scanner context. CBD placebo effects may be sufficient to alter neural responses relevant to its purported anxiolytic and stress-relieving properties. Future work is needed to replicate these results and determine whether CBD expectancy and pharmacology interact to alter neural anxiety reactivity and stress reactivity.

Toward diversification of acute stressors and precision stress research: A stage 2 Registered Report validating a reward-salient stress task in emerging adults.

Stress is one of, if not the, most ubiquitously studied risk factor across the health sciences. This is unlikely to change given that the primary drivers of mortality and disability are chronic, stress-mediated illnesses (often highly comorbid with psychopathology). We argue that an important limitation of stress research is the consistency with which the Trier Social Stress Test is used when the research questions are not specific to social stress. We advocate for precision stress research using qualitatively different stressors to facilitate exploration of how different types of stressors might differentially impact health outcomes, including psychopathology. This registered report validates a reward-salient stress task (a modified Anger Incentive Delay Task) in a sample of 101 emerging adults, over half of whom reported clinically relevant anxiety, hypo/mania, depression, and/or suicidal ideation, who participated in a study between 2020 and 2022. This task involves teaching participants a game where they can win money. Part way through, the "goal frustration" condition changes the rules such that correct responses to trials with anticipatory stimuli indicating the possibility to win money actually lose money on 56% of trials despite visual feedback indicating that responses were successful. Results consistently indicated that the Anger Incentive Delay Task successfully reduced positive emotions and motivation and increased negative emotions. The magnitude of these responses was predicted by individual differences in reward and punishment sensitivity. Given the breadth of psychopathologies that share both (a) stress and (b) reward and punishment sensitivity as risk factors, a reward-salient acute stress task is an important tool for precision psychopathology research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Supplemental Material for Toward Diversification of Acute Stressors and Precision Stress Research: A Stage 2 Registered Report Validating a Reward-Salient Stress Task in Emerging Adults

Supplemental Material for Toward Diversification of Acute Stressors and Precision Stress Research: A Stage 2 Registered Report Validating a Reward-Salient Stress Task in Emerging Adults

Using mobile eye-tracking to evaluate gaze behavior during a speech in pediatric anxiety disorders

BackgroundAltered gaze in social settings is a hallmark of social anxiety; however, little research directly examines gaze in anxiety-provoking contexts among youth with anxiety disorders, limiting mechanistic insight into pediatric anxiety. The present study leveraged mobile eye-tracking technology to examine gaze behavior during a naturalistic stressor in a clinical developmental sample. MethodsSixty-one youth (ages 8–17 years; 28 with anxiety disorders, 33 non-anxious controls) completed a naturalistic social stress task (public speaking in front of a videotaped classroom audience) while wearing eye-tracking glasses. Gaze behavior and state anxiety were quantified in each group during two task conditions: while giving a speech and while passively viewing the audience. ResultsAnxiety-related differences emerged in state anxiety and gaze behavior. First, a significant interaction between diagnostic group and task condition on state anxiety indicated that while anxiety increased among non-anxious controls following the speech, youth with anxiety disorders reported persistently elevated anxiety across all assessments. Second, a significant interaction emerged between social anxiety symptom severity and task condition on gaze time on the audience. While youth overall showed low dwell time on the audience during speech delivery, individuals with greater social anxiety showed longer gaze on the audience during the passive viewing condition. This pattern was specific to dimensional analyses of social anxiety symptom severity. LimitationsThe current study was not sufficiently powered to examine age-related differences. ConclusionsThese findings highlight anxiety-related differences in gaze behavior in youth, providing new mechanistic insight into pediatric anxiety using mobile eye-tracking.

Wearable EEG-Based Brain-Computer Interface for Stress Monitoring.

Detecting stress is important for improving human health and potential, because moderate levels of stress may motivate people towards better performance at cognitive tasks, while chronic stress exposure causes impaired performance and health risks. We propose a Brain-Computer Interface (BCI) system to detect stress in the context of high-pressure work environments. The BCI system includes an electroencephalogram (EEG) headband with dry electrodes and an electrocardiogram (ECG) chest belt. We collected EEG and ECG data from 40 participants during two stressful cognitive tasks: the Cognitive Vigilance Task (CVT), and the Multi-Modal Integration Task (MMIT) we designed. We also recorded self-reported stress levels using the Dundee Stress State Questionnaire (DSSQ). The DSSQ results indicated that performing the MMIT led to significant increases in stress, while performing the CVT did not. Subsequently, we trained two different models to classify stress from non-stress states, one using EEG features, and the other using heart rate variability (HRV) features extracted from the ECG. Our EEG-based model achieved an overall accuracy of 81.0% for MMIT and 77.2% for CVT. However, our HRV-based model only achieved 62.1% accuracy for CVT and 56.0% for MMIT. We conclude that EEG is an effective predictor of stress in the context of stressful cognitive tasks. Our proposed BCI system shows promise in evaluating mental stress in high-pressure work environments, particularly when utilizing an EEG-based BCI.

Individual differences in parasympathetic functioning across social stressor tasks: Relations with child and parent anxiety

AbstractChildren with elevated behavioural inhibition (BI) show context‐inappropriate fear and dysregulated RSA across stressor tasks. However, few studies have examined dynamic RSA within tasks and relations to parent and child anxiety. Using piecewise growth modelling and multimethod baseline data from an intervention study of 151 3.5–5‐year‐old children and their parents, we examined relations between child social anxiety (SA), parent anxiety and their interaction in predicting children's RSA across social stressor tasks (e.g. learning about unfamiliar peers, Trier Social Stress). Within the sample, 49.63% of children were reported to be White, non‐Hispanic/Latine (n = 67), 22% multiracial (n = 31), 14.81% Asian/Pacific Islander (n = 20) and 12.59% Black/African‐American (n = 17). Furthermore, 64.44% of the parents were reported to be White, non‐Hispanic/Latine (n = 87), 20% Asian/Pacific Islander (n = 27), 13.33% Black/African‐American (n = 18) and 2.22% multiracial (n = 3). Children showed differentiated RSA reactivity and recovery within an anticipatory social learning task based on their level of clinically appraised SA. Relations between child SA and RSA across tasks was moderated by parent anxiety, specifically for dyads matched in anxiety. Findings provide support for the potential influence of both child and parent anxiety on children's parasympathetic nervous system (PNS) responses across specific self‐regulatory tasks.

The effect of guided group reflection on the ability and convenience of breaking bad news in pre-hospital emergency staff

BackgroundBad news refers to any information that create negative changes in a person’s understanding or expectations of in present and future. Breaking Bad News (BBN) is a stressful task that may have disturbing effects on the professional performance and general health of the medical staff. Pre-hospital emergency staff often needs to deliver bad news to the patient or his family. This study was conducted to determine the effect of guided group reflection training on the ability and comfort of BBN in pre-hospital emergency staff.MethodsThis quasi-experimental study was conducted on 95 staff of the pre-hospital emergency, in the test and the control groups. For the test group, a 4-hour training workshop on BBN was held, and then a group was formed in virtual space to discuss and exchange opinions about the scenarios of BBN and reflecting on it. Data collection tools were SPIKES Questionnaire and the Visual Analogue Mood Scale. The data were analyzed with SPSS V.18.ResultsThe mean score of the ability to BBN after the intervention was 44.01 ± 6.21 in the test group and 31.40 ± 4.51 in the control group, and a significant difference was found using the independent t-test (P = 0.0001). Besides, the mean scores of the convenience of BBN in post-test was 5.52 ± 1.64 in the test group and 3.50 ± 1.28 in the control group using the independent t-test with a significant difference (P = 0.0001).ConclusionAccording to the findings, training in guided group reflection improved the ability to BBN and its convenience in pre-hospital emergency staff. Therefore, it is suggested the use of this method in training for health care providers. Relating to BBN.

Childhood trauma and social anxiety in adolescents: Mediating role of cardiovascular response to social stress.

Adolescents exposed to childhood trauma are at an elevated risk for social anxiety. However, the physiological mechanisms linking childhood trauma and adolescents' social anxiety remain poorly understood. This study examined whether cardiovascular reactivity to acute social stress was a mechanism underlying this association. Participants were Chinese adolescents (N = 172; Mage = 12.95). They first reported their childhood trauma and social anxiety using the Childhood Trauma Questionnaire and the Social Interaction Anxiety Scale. They then participated in a social stress task, during which their cardiovascular data [heart rate (HR) and systolic and diastolic blood pressure (SBP, DBP)] were monitored. The results showed that high levels of childhood trauma were associated with blunted HR, SBP, and DBP reactivity, which in turn were associated with high levels of social anxiety. Mediation analysis indicated that childhood trauma was indirectly associated with social anxiety via blunted cardiovascular reactivity. The findings suggest that blunted cardiovascular reactivity may serve as a physiological pathway linking childhood trauma and adolescents' social anxiety.

Stress responses of infants and mothers to a still-face paradigm after traumatic childbirth

IntroductionOne-third of women experience childbirth as traumatic and some develop symptoms of childbirth-related posttraumatic stress symptoms (CB-PTSS). Whether CB-PTSS negatively impact on physiological and psychological stress responses in mothers and their offspring and whether they are associated with mother-infant synchrony is not clear. This study aimed to investigate stress responses of (1) mothers with CB-PTSS, (2) of their infant, and (3) the physiological mother-child-synchrony at six months postpartum. MethodPsychophysiological (cortisol and vagal tone) and psychological stress responses of mothers and infant’s (n=31 dyads) from the Swiss TrAumatic biRth Trial (NCT03576586) were assessed during a face-to-face still-face paradigm (FFSF-R). ResultsThere was a significant time effect in maternal stress responses for salivary cortisol, vagal tone, and for maternal subjective stress. As expected, mothers’ subjective stress increased during the stress task and mothers vagal tone changed during the first stressful period but not during the second, whereas cortisol unexpectedly decreased over the FFSF-R. Infant negative mood increased over the experiment, but there were no physiological changes. However, a significant interaction effect for mother-infant synchrony during the second reunion period of the FFSF-R was found. ConclusionAlthough mothers and their infants were subjectively stressed, they showed only limited physiological stress responses.

The Short Stress State Questionnaire in German (SSSQ-G)

Abstract: Background: Although the physiological stress response is well established, self-reported stress has received less attention. Some validated measures assess task-related stress via self-report in English. However, no such measure exists in Germany. Aims: To address this research gap, we translated and validated the Short Stress State Questionnaire in German (SSSQ-G). It assesses stress-related affective states (e.g., anger) and appraisals (e.g., feelings of control). We expected to replicate the factor structure of the English SSSQ in the SSSQ-G. Methods: We included the SSSQ-G in five studies that induced stress either via the gold standard task for acute stress induction – the Trier Social Stress Test (TSST) – or via a novel virtual reality (VR) task. The sample consisted of 213 participants (112 women; age: 23.36 ± 3.62 years). Results: The SSSQ-G demonstrated sensitivity to stress-induced changes ( ps < .01), particularly in response to the TSST compared to the VR stress induction ( p < .001 for total scale comparison between stressors). In TSST participants, the magnitudes of stress-induced changes on the SSSQ-G were larger than those on the Positive and Negative Affect Schedule (PANAS), p = .008, indicating strong construct validity. Although the SSSQ-G total score was highly reliable (α = .85, Ω = .86), factor analyses revealed a six-factor solution, with the factors representing Distress, Worry, Confidence, Negative affect, Motivation, and Self-evaluation. Limitations: The SSSQ-G appears more sensitive to state changes induced by moderate-to-severe stress tasks. Conclusion: The SSSQ-G is a reliable and valid instrument for assessing states of subjective stress.

Exposure to diesel-related particulate matter, cortisol stress responsivity, and depressive symptoms in adolescents

Exposure to air pollution is associated with higher risk for psychopathology; however, the mechanisms underlying this association are not clear. Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis in response to stress has been implicated in depression. Here, we estimated annual exposure to particulate matter (PM) from diesel emissions in 170 9- to 15-year-old adolescents (56 % female) using their residential addresses and data from nearby monitoring sites. We obtained salivary cortisol samples from participants while they completed a social stress task and calculated area under the curve with respect to ground (AUCg) and with respect to increase (AUCi) in order to assess cortisol responsivity during stress. Participants also reported on their depressive symptoms and sleep disturbances. Greater exposure to diesel PM was associated with lower cortisol output (AUCg) during stress, which was associated with higher depressive symptoms, particularly for adolescents with more sleep disturbances. Importantly, these effects were independent of household and neighborhood socioeconomic disadvantage and exposure to early adversity. Thus, HPA-axis dysfunction may be one mechanism through which environmental pollutants affect adolescents’ mental health.

Examining the applicability of virtual battle space for stress management training in military personnel-A validation study.

Military personnel are often exposed to high levels of both physical and psychological challenges in their work environment and therefore it is important to be trained on how to handle stressful situations. The primary aim of this study was to examine whether military-specific virtual battle space (VBS) scenarios could elicit a physiological and subjective stress response in healthy military personnel, as compared to that of a virtual reality height exposure (VR-HE) stress task that has shown to reliably increase stress levels. Twenty participants engaged in two VBS scenarios and the VR-HE during separate sessions, while measurements of heart rate (HR), heart rate variability (HRV), respiration rate, and subjective stress levels were collected. Contrary to our initial expectations, analysis revealed that neither of the VBS scenarios induced a significant stress response, as indicated by stable HR, HRV, and low subjective stress levels. However, the VR-HE task did elicit a significant physiological stress response, evidenced by increased HR and HRV changes, aligning with previous research findings. Moreover, no discernible alterations were detected in cognitive performance subsequent to these stressors. These results suggest that the current VBS scenarios, despite their potential, may not be effective for stress-related training activities within military settings. The absence of a significant stress response in the VBS conditions points to the need for more immersive and engaging scenarios. By integrating interactive and demanding elements, as well as physical feedback systems and real-time communication, VBS training might better mimic real-world stressors and improve stress resilience in military personnel. The findings of this study have broader implications for stress research and training, suggesting the need for scenario design improvements in virtual training environments to effectively induce stress and improve stress management across various high-stress professions.

Suicidality, perceived chronic stress, and stress-induced cortisol changes of individuals with schizophrenia.

The associations of suicidality with stress are poorly studied in schizophrenia. The study aimed to determine whether suicidality was correlated with perceived chronic stress and the cortisol fluctuations under stress tasks in schizophrenia. High suicidality was defined as a lifetime history of suicide attempts or suicidal ideation in the past 2weeks. Individuals with schizophrenia and high suicidality (SZ-HS, n=59), with low suicidality (SZ-LS, n=207), and healthy controls (HC, n=196) finished the Perceived Stress Scale. Then, they participated in an experiment that induced stress using the Paced Auditory Serial Addition Task and the Mirror Tracing Persistence Task. Negative affect was measured at baseline and after finishing each task. The salivary cortisol was collected before-, after 20min, and after 40min of the tasks. SZ-HS had elevated perceived stress than SZ-LS and HC. Mixed effect models showed that stress tasks induced cortisol changes in all groups; cortisol of SZ-LS was reduced more than HC, but SZ-HS and SZ-LS did not differ in cortisol fluctuations. SZ-HS and SZ-LS experienced similar negative affect changes during tasks and the difference in withdrawal rates was nonsignificant. SZ-HS had an increased error rate than SZ-LS. In conclusion, suicidality was correlated with high-level perceived stress but did not result in differences in cortisol reactivities under stress tasks. It suggests the inconsistency between appraisal of stress and biological stress system disturbance among SZ-HS compared to SZ-LS.

Shock Me The Way: Directional Electrotactile Feedback under the Smartwatch as a Navigation Aid for Cyclists

Cycling navigation is a complex and stressful task as the cyclist needs to focus simultaneously on the navigation, the road, and other road users. We propose directional electrotactile feedback at the wrist to reduce the auditory and visual load during navigation-aided cycling. We designed a custom electrotactile grid with 9 electrodes that is clipped under a smartwatch. In a preliminary study we identified suitable calibration settings and gained first insights about a suitable electrode layout. In a subsequent laboratory study we showed that a direction can be encoded with a mean error of 19.28\,° (σ = 42.77°) by combining 2 adjacent electrodes. Additionally, by interpolating with 3 electrodes a direction can be conveyed with a similar mean error of 22.54° (σ = 43.57°). We evaluated our concept of directional electrotactile feedback for cyclists in an outdoor study, in which 98.8% of all junctions were taken correctly by eight study participants. Only one participant deviated substantially from the optimal path, but was successfully navigated back to the original route by our system.