Subjective Stress, Salivary Cortisol, and Electrophysiological Responses to Psychological Stress

Challenge Your Body, Challenge Your Mind: the Combined Effect of Fitness Level and Stress Appraisal on Stress Responses and Subsequent Cognitive Performance

BACKGROUND

Because of the health issues associated with high stress levels, it is important to find new strategies to regulate stress response. Previous research has examined the separate effects of fitness level and stress reappraisal on the stress response, but the combination of both factors is unknown. The goal of the study was to examine the combined effects of fitness and stress appraisal on stress responses and cognitive performance following a stressful event.

METHOD

On 2 separate days, 24 highly and poorly fit young men (Mage = 22.33, SD = 3.33) were exposed to a validated stress test and were induced to view their stress as facilitative or debilitative. Objective and subjective stress responses along with cognitive performance were evaluated before and immediately after the stress test.

RESULTS

Participants in the high-fit/negative appraisal condition reported lower anxiety scores than participants in the low-fit/negative appraisal condition (d = 1.04). Participants had higher levels of cortisol after the stress test (d = 0.31), but no difference in heart rate, cortisol, or cognitive performance emerged among the conditions.

CONCLUSION

Fitness level might have a larger impact on stress response than stress appraisal, and stress reappraisal manipulations require more than just reading a note and a self-talk statement.

Emotional, physiological, biochemical, and behavioral responses to acute stress and uncertainty in military personnel

Stress carries diverse implications for perceptual, cognitive, and affective functions. One population particularly susceptible to acute stress-induced cognitive changes are individuals with high-stress jobs (e.g., military personnel). These individuals are often tasked with maintaining peak cognitive performance, including memory, spatial navigation, and decision-making under threatening and uncertain conditions. Previous research has separately examined decision-making under conditions of stress or uncertainty (i.e., ambiguous discrimination between friends and foes). However, questions remain about how operationally relevant stress impacts memory encoding and recall, or spatial learning, as well as how uncertainty may impact decision-making during stress. To address this gap, we examined the influence of a military-relevant emotional stressor on a series of cognitive tasks including recognition memory task (RMT), spatial orienting task (SOT), and shoot/don't shoot decision making (DMT). To examine the effects of uncertainty and stress we varied the stimulus clarity in the DMT. We utilized threat of shock (TOS) as a high-stakes outcome for decision errors. TOS increased sympathetic arousal but did not affect subjective emotional or HPA responses. TOS influenced decision times and confidence ratings in the DMT, but not response sensitivity or response bias. DMT performance varied by stimulus clarity (uncertainty) but did not differ between stress conditions. TOS did not influence recognition memory or spatial orienting. In sum, high levels of stress and uncertainty characterize military operations, yet stress experienced in military contexts can be difficult to induce in laboratory settings. We discuss several avenues for future research, including methodological considerations to better assess the magnitude and specificity of emotional stress-induction techniques in Soldiers.

The Impact of Cannabidiol Expectancy on Cortisol Responsivity in the Context of Acute Stress: Associations with Biological Sex

Background: Cannabidiol (CBD), a nonpsychoactive cannabinoid found in the cannabis plant, has gained interest for its purported stress- and anxiety-reducing effects. However, the mechanisms underlying these effects remain unclear. Our group previously found that CBD expectancy alone resulted in lower state anxiety (vs. CBD-free expectancy) among those who strongly believed it was helpful for such purposes, in addition to influencing physiological measures (i.e., heart rate variability). Aims: Using data collected as part of this previously published larger study, we aimed to explore the extent to which CBD expectancy alone impacts cortisol in the context of a laboratory stressor. Methods: A sample of 43 healthy adults (23 female) participated in one orientation and two experimental laboratory sessions. They received the same oil (CBD-free) during both experimental sessions but were told they received CBD oil in counterbalanced order in one of their sessions. Participants then engaged in a laboratory stressor (the Maastricht Acute Stress Test; MAST) and salivary cortisol samples were collected throughout [T1: baseline; T2: 90-min postabsorption (PA); T3: poststress (0-PS); T4: 10-min poststress (10-PS); T5: 30-min poststress (30-PS)]. Linear marginal models were used for analyses. Results: Findings indicated that a physiological stress response was elicited in the context of the MAST, which is consistent with what has been reported previously. Interestingly, while cortisol levels were significantly lower in the CBD expectancy condition (vs. CBD-free) immediately following the MAST (0-PS) and 10-min later (10-PS), this effect seems to be largely driven by males, evidenced by a three-way interaction. Cortisol levels did not reliably vary across expectancy conditions at any other time point. Conclusion: Overall, these results suggest that CBD expectancy appears to blunt cortisol in anticipation of a stressor, particularly in males. Findings suggest that it is important to consider the impact of drug-related expectations when assessing CBD-related effects on stress-related processes.

A Hybrid EEG-Based Stress State Classification Model Using Multi-Domain Transfer Entropy and PCANet

This paper proposes a new hybrid model for classifying stress states using EEG signals, combining multi-domain transfer entropy (TrEn) with a two-dimensional PCANet (2D-PCANet) approach. The aim is to create an automated system for identifying stress levels, which is crucial for early intervention and mental health management. A major challenge in this field lies in extracting meaningful emotional information from the complex patterns observed in EEG. Our model addresses this by initially applying independent component analysis (ICA) to purify the EEG signals, enhancing the clarity for further analysis. We then leverage the adaptability of the fractional Fourier transform (FrFT) to represent the EEG data in time, frequency, and time-frequency domains. This multi-domain representation allows for a more nuanced understanding of the brain's activity in response to stress. The subsequent stage involves the deployment of a two-layer 2D-PCANet network designed to autonomously distill EEG features associated with stress. These features are then classified by a support vector machine (SVM) to determine the stress state. Moreover, stress induction and data acquisition experiments are designed. We employed two distinct tasks known to trigger stress responses. Other stress-inducing elements that enhance the stress response were included in the experimental design, such as time limits and performance feedback. The EEG data collected from 15 participants were retained. The proposed algorithm achieves an average accuracy of over 92% on this self-collected dataset, enabling stress state detection under different task-induced conditions.

Glucocorticoid response to naturalistic interactions between children and dogs

Although research has shown that pets appear to provide certain types of social support to children, little is known about the physiological bases of these effects, especially in naturalistic contexts. In this study, we investigated the effect of free-form interactions between children (ages 8-10 years) and dogs on salivary cortisol concentrations in both species. We further investigated the role of the child-dog relationship by comparing interactions with the child's pet dog to interactions with an unfamiliar dog or a nonsocial control condition, and modeled associations between survey measures of the human-animal bond and children's physiological responses. In both children and dogs, salivary cortisol decreased from pre- to post-interaction; the effect was strongest for children interacting with an unfamiliar dog (compared to their pet dog) and for the pet dogs (compared to the unfamiliar dog). We found minimal evidence for associations between cortisol output and behaviors coded from video, but children scoring higher on survey measures of the human-animal bond exhibited the greatest reductions in cortisol when interacting with dogs. Self-reported loneliness was not related to cortisol or the human-animal bond, but measures of both loneliness and the human-animal bond were higher among children who participated after the onset of the COVID-19 pandemic, relative to those who participated before the pandemic. This study builds on previous work that investigated potential stress-buffering effects of human-animal interaction during explicit stressors and demonstrates important physiological correlates of naturalistic interactions between children and dogs, similar to those that occur in daily life.

Effect of Acute Psychological Stress on Speed Perception: An Event-Related Potential Study

The present study tested the intrinsic ERP features of the effects of acute psychological stress on speed perception. A mental arithmetic task was used to induce acute psychological stress, and the light spot task was used to evaluate speed perception. Compared with judgments in the constant speed and uniform acceleration motion, judgments in the uniform deceleration motion were made more quickly and with higher accuracy; attention control was higher and peaked later; and there was longer N2 peak latency, larger N2 peak amplitude, and lower mean amplitude of the late negative slow wave (SW). Under stress, the reaction time was significantly shorter. The N2 peak amplitude and SW mean amplitude were significantly higher, attention control was higher and appeared earlier, and there was a greater investment of cognitive resources. The type of movement and evoked stress also interacted to predict behavioral and ERP measures. Under acute stress, judgments made in the uniform deceleration motion condition elicited lower N2 peak latency, higher attention control, and later peak attention. The results suggest that judgments of the speed of decelerating motion require a lower investment of cognitive resources than judgments of other kinds of motion, especially under acute stress. These findings are best interpreted in terms of the interaction of arousal and attention.

Self-awareness protects working memory in people under chronic stress: An ERP study

Chronic stress impairs working memory (WM), but few studies have explored the protective factors of the impairment. We aimed to investigate the effect of self-awareness on WM processing in people under chronic stress. Participants under chronic stress completed an n-back task after a self-awareness priming paradigm during which electroencephalograms were recorded. The behavioral results showed that participants whose self-awareness was primed reacted faster and more accurately than the controls. Event-related potentials (ERPs) revealed the following (1) P2 was more positive in the self-awareness group than in the controls, indicating that self-awareness enhanced allocation of attention resources at the encoding stage. (2) N2 was attenuated in the self-awareness group compared with the controls, indicating that smaller attention control efforts were required to complete WM tasks adequately after self-awareness priming; and (3) enhanced late positive potential (LPP) was evoked in the self-awareness group compared with the controls, suggesting self-awareness enabled participants to focus attention resources on the information at the maintenance stage. Critically, mediational analyses showed that LPP mediated the relationship between self-awareness and WM response times. This result suggests that the fact that participants whose self-awareness was primed were able to achieve better behavioral performances may be attributed to their mobilization of sustained attention resources at the maintenance stage. In summary, self-awareness exerted a protective effect on WM in those under chronic stress, which may be due to the enhancements in the allocation and mobilization of attention. These results could be used to develop more specific coping strategies for people under chronic stress.

Antibody-Coated Wearable Organic Electrochemical Transistors for Cortisol Detection in Human Sweat

The dysregulation of the hormone cortisol is related to several pathological states, and its monitoring could help prevent severe stress, fatigue, and mental diseases. While wearable antibody-based biosensors could allow real-time and simple monitoring of antigens, an accurate and low-cost antibody-based cortisol detection through electrochemical methods is considerably challenging due to its low concentration and the high ionic strength of real biofluids. Here, a label-free and fast sensor for cortisol detection is proposed based on antibody-coated organic electrochemical transistors. The developed devices show unprecedented high sensitivities of 50 μA/dec for cortisol sensing in high-ionic-strength solutions with effective cortisol detection demonstrated with real human sweat. The sensing mechanism is analyzed through impedance spectroscopy and confirmed with electrical models. Compared to existing methods requiring bulky and expensive laboratory equipment, these wearable devices enable point-of-care cortisol detection in 5 min with direct sweat collection for personalized well-being monitoring.

Nx4 attenuated stress-induced activity of the anterior cingulate cortex-A post-hoc analysis of a randomized placebo-controlled crossover trial

OBJECTIVE

Stress-related symptoms are associated with significant health and economic burden. Several studies suggest Nx4 for the pharmacological management of the stress response and investigated the underlying neural processes. Here we hypothesized that Nx4 can directly affect the stress response in a predefined stress network, including the anterior cingulate cortex (ACC), which is linked to various stress-related symptoms in patients.

METHODS

In a randomized, placebo-controlled, double-blind, crossover trial, 39 healthy males took a single dose of placebo or Nx4. Psychosocial stress was induced by the ScanSTRESS paradigm inside an MRI scanner, and stress network activation was analyzed in brain regions defined a priori.

RESULTS

Using the placebo data only, we could validate the activation of a distinct neural stress pattern by the ScanSTRESS paradigm. For Nx4, we provide evidence of an attenuating effect on this stress response. A statistically significant reduction in differential stress-induced activation in the right supracallosal ACC was observed for the rotation stress task of the ScanSTRESS paradigm. The results add to previously published results of Nx4 effects on emotion regulation.

CONCLUSIONS

Our results strengthen the hypothesis that Nx4 modulates the stress response by reducing the activation in parts of the neural stress network, particularly in the ACC.

TRIAL REGISTRATION

NCT02602275; ClinicalTrials.gov.

Neither Threat of Shock nor Acute Psychosocial Stress Affects Ambiguity Attitudes

Decisions under uncertainty can be differentiated into two classes: risky, which has known probabilistic outcomes, and ambiguous, which has unknown probabilistic outcomes. Across a variety of types of decisions, people find ambiguity extremely aversive, subjectively more aversive than risk. It has been shown that the transient sympathetic arousal response to a choice predicts decisions under ambiguity but not risk, and that lifetime stress uniquely predicts attitudes toward ambiguity. Building on these findings, this study explored whether we could bias ambiguity and risk preferences with an arousal or acute stress manipulation that is incidental to the choice in two independent experiments. One experiment induced sympathetic arousal with an anticipatory threat paradigm, and the other manipulated incidental acute stress via a psychosocial stressor. The efficacy of the manipulations was confirmed via pupil dilation and salivary cortisol, respectively. Participants made choices between a guaranteed $5 option and a lottery with either a known (risky) or unknown (ambiguous) probabilistic outcome. Consistent with previous findings, participants were more averse to a given level of ambiguity than to a numerically equal level of risk. However, in contrast to our hypothesis, we found no evidence that transient arousal or acute stress that is incidental to the choice biases ambiguity preferences.

The Effect of a Probiotic Complex on the Gut-Brain Axis: A Translational Study

BACKGROUND

The gut-brain axis refers to the network of connections that involve multiple biologic systems, allowing bidirectional communication between the gut and the brain. This communication is mainly mediated by gut microbiota, thanks to its ability to modulate several processes like the production of neurotransmitters. As such, keeping a balanced gut microbiota through probiotic intake could be a valid solution in supporting the right gut-brain communications.

METHODS

A two-step in vitro screening of five different probiotic strains was carried out to select the best performers in the modulation of stress markers. A first selection on SK-N-DZ neuronal cell lines was performed to evaluate the inhibition of the epigenetic enzyme LSD1, promotion of GABA, and expression of serotonin. Three out of five strains were tested for their ability to promote serotonin synthesis in the Caco2 cell line. As a result, Limosilactobacillus reuteri PBS072 and Bifidobacterium breve BB077 were selected as the best performing strains. To confirm their effects in humans, a proof-of-concept trial was carried out to evaluate stress-related parameters for 28 days of product intake in a group of 30 stressed students.

RESULTS

A significant improvement of cognitive functions, in terms of short-term memory, attention, and executive performance, as well as of psychophysiological markers, such as salivary cortisol level, skin conductance, sleep quality, and anxiety, were observed.

CONCLUSIONS

According to the results, L. reuteri PBS072 and B. breve BB077 are potential probiotic candidates for improving stress resilience, cognitive functions, and sleep quality.

Influence of acute stress on attentional bias toward threat: How a previous trauma exposure disrupts threat apprehension

While previous trauma exposure is known to be a risk factor for the development and maintenance of many psychological disorders, it remains unclear how it increases individual risk for prospective psychopathology in the aftermath of a new trauma exposure. The aim of this study was to investigate how a prior exposure to trauma affects attentional processing of threat before and after an acute stress task. Specifically, we assessed attentional biases to threat before and after a cold pressor task in 17 individuals who have been exposed to trauma (TE) compared to 18 individuals without trauma exposure (NTE). Behavioral results showed difficulties to disengage from threat in TE but not in the control group prior to stress induction, as well as a switch to an attentional bias toward threat after the cold pressor task in the TE group. For the ERPs, we highlighted (1) decreased N1 negativity in response to threatening stimuli after an acute stress in both groups, and (2) a parallel increase in P1 for such stimuli only in the TE group. Those results suggest a vulnerability presented by previously traumatized individuals when dealing with threats as well as an acute responsitity toward stress. Those results are interpreted in regards with the theorical models of stress and anxiety.

Stress effects on the oddball P300 and N2 in males and females

We examined the effect of psychosocial stress on electrophysiological markers of novelty and deviance processing, the N2 and P300, as well as sex differences therein. Participants underwent the Trier Social Stress Test (TSST) or a control procedure, followed by an oddball paradigm. A physiological stress response was induced in both sexes in the TSST condition. Furthermore, a reduced target P300 amplitude was elicited in the TSST condition in fronto-central electrodes, an effect that did not differ in magnitude between both sexes. By contrast, stressor effects on N2 amplitude differed by sex: In females, N2 amplitude was decreased in the TSST condition, while in males, no stress effects were observed. Exploratory correlational analyses suggested that a stress-induced P300 amplitude reduction, at least in males, could be due to a modulation of adrenergic activity. These results are consistent with sex differences in the manner in which stress affects lower-level, stimulus-driven vs. higher-level, more controlled processing stages.

The influence of specific aspects of occupational stress on security guards' health and work ability: detailed extension of a previous study

In our earlier study of security guards, we showed that higher occupational stress was associated with health impairments (metabolic syndrome, diabetes, hypertension, cardiovascular diseases) and work disability. The aim of this study was to further explore the association of specific occupational stressors with health impairments and work disability parameters in 399 Serbian male security guards (aged 25–65 years). Ridge linear regression analysis revealed that, after controlling for age, body mass index, and smoking status, professional stressors including high demands, strictness, conflict/uncertainty, threat avoidance and underload were significant positive predictors of fasting glucose, triglycerides, total and LDL cholesterol, blood pressure, heart rate, Framingham cardiovascular risk score, and temporary work disability. The security profession is in expansion worldwide, and more studies are needed to establish precise health risk predictors, since such data are generally lacking.

Effect of Acute Psychological Stress on Motion-in-Depth Perception: An Event-Related Potential Study

The present study explored the intrinsic event-related potential (ERP) features of the effects of acute psychological stress on the processing of motion-in-depth perception using a dual-task paradigm. After a mental arithmetic task was used to induce acute psychological stress, a collision task was used to evaluate motion-in-depth perception. The error value and average amplitude of late slow waves (SW) were significantly larger for the earlier colliding spheres' than for the later colliding spheres. The P1 peak latency in the left occipital region was significantly shorter than that of the right occipital region in the motion-in-depth perception task. Compared to the control condition, the estimated value of residual time-to-collision and error value were significantly reduced, and the N1 peak amplitude and the SW averaged amplitude were significantly increased in the stress condition. Longer motion-in-depth time improved discrimination accuracy and decreased the investment of cognitive resources. Acute psychological stress increased behavioral performance and enhanced attention resources on the motion-in-depth perception task together with greater investment of cognitive resources.

Stressor-Oriented MUlticomponent Intervention and the WeLl-Being of Patients with Alzheimer's Disease: A Randomized Controlled Trial (SOUL-P)

BACKGROUND

Patients with Alzheimer's disease (AD) experience various stressors that negatively impact well-being. Most studies have, however, small effect size and are limited by the experiences of severe patients. Therefore, we conducted a single-blind, randomized controlled trial, which has included patients at different stages.

OBJECTIVE

The stressor-oriented multicomponent program was designed as an intervention for AD patients to enhance well-being.

METHODS

Patients were randomly assigned to control or SOUL-P conditions according to disease severity. The SOUL-P group received 15 intensive sessions over 6 months and 6 maintenance sessions over a 6-month follow-up by a multidisciplinary team comprising psychologists, occupational therapists, and community nurses. The control group received a similar number of sessions by community nurses. Stress-related outcomes (primary stressors and well-being outcomes) were obtained from in-person baseline and follow-up interviews conducted at 6- and 12-months post-baseline. A treatment compliance survey was conducted at the intervention endpoint for patients.

RESULTS

Of the 863 patients screened, 218 (25.3%) were eligible. At 6 months, compared to controls, SOUL-P patients had improved quality of life (QoL) (p < 0.001; Cohen d = 0.56), depression (p = 0.020; Cohen d = -0.33), neurobehavioral symptoms (p = 0.034; Cohen d = -0.30), perceived stress (p = 0.030; Cohen d = -0.31), and family conflict (p = 0.026; Cohen d = -0.32). QoL, depression, perceived stress, and family conflict were still significantly different at 12 months. Most patients were satisfied with SOUL-P, while caregivers in the SOUL-P group reported overloading tasks.

CONCLUSION

SOUL-P may reduce perceived stress and improve psychological outcomes in AD patients. Stressor-based interventions, patient-oriented goals, and a multidisciplinary team are essential features for a successful SOUL-P.

Event-related brain potentials related to the identification of different types of signs

The present study examined the electrophysiological activity during the processing in the identification of signs. Participants performed a sign identification task, in which real, pseudo, and fake signs were adopted as stimuli. Common mathematical operation signs (e.g. +, -, ×, and ÷), which were known to the participants were adopted as the real signs. The pseudo signs had a similar appearance to the real signs (e.g. (Equation is included in full-text article.), (Equation is included in full-text article.), ×, and ÷). The fake signs were also unknown, but had an entirely different shape from the real signs (e.g. (Equation is included in full-text article.), (Equation is included in full-text article.), (Equation is included in full-text article.), and (Equation is included in full-text article.)). The behavioral results showed inferior recognition performance for pseudo signs relative to real or fake signs. Event-related potential results showed that (a) pseudo signs evoked a more positive P200 component than did real or fake signs, suggesting that more attentional resources might be allocated to the pseudo signs relative to the real or fake signs and (b) fake signs evoked a more negative N300 component than real or pseudo signs, suggesting that more cognitive resources might be recruited in processing the visual aspects for fake signs relative to real or pseudo signs. These results suggested that the P200 component, which is associated with attentional resource allocation, and the N300, which is sensitive to visual aspects, were evoked in processing the signs.

The Power of Faith: The Influence of Athletes' Coping Self-Efficacy on the Cognitive Processing of Psychological Stress

Coping self-efficacy (CSE) has a positive mental health effect on athletes’ ability to cope with stress. To understand the mechanism underlying the potential impact of CSE, event-related potentials (ERPs) were used to explore the neural activity of the cerebral cortex under acute psychological stress in athletes with different CSE levels. Among 106 high-level athletes, 21 high-CSE athletes and 20 low-CSE athletes were selected to participate in the experiment. A mental arithmetic task was used to induce acute psychological stress. The results showed that high-CSE athletes responded more quickly than low-CSE athletes. In the stress response stage, the N1 peak latency of low-CSE athletes was longer than that of high-CSE athletes, and the N1 amplitude was significantly larger than that of high-CSE athletes. In the feedback stage, the FRN amplitude with error feedback of high-CSE athletes was larger than that of low-CSE athletes, and the P300 amplitude with correct feedback was larger than that with error feedback. The results indicate that high-CSE athletes can better cope with stressful events, adjust their behaviors in a timely manner according to the results of their coping, and focus more on processing positive information.

Female Volleyball Players Are More Prone to Cortisol Anticipatory Stress Response than Sedentary Women

Background and Objectives: Top-level sports performance places heavy physical and psychological demands on elite-level athletes, which can be a source of increased levels of stress. Therefore, high-level volleyball players may present altered cardiovascular and endocrinological stress response during stressful events. Although many previous studies have examined the response to stress on athletes, most of them regarded only males, while the impact of the female menstrual cycle has rarely been taken into account. We aimed to study psychophysiological response to anticipatory stressor through analysis of heart rate, self-reported anxiety level, and salivary cortisol in healthy young female athletes by minimalizing the effect of confounders. Materials and Methods: A total of 55 females (25 members of the best league for female volleyball players in Poland and 30 sedentary-lifestyle control subjects) in the follicular phase of their menstrual cycle were exposed to mental arithmetic tasks as an experimental imitation of the stressor. Volleyball players were significantly taller than sedentary individuals (177.1 ± 3.4 cm vs. 173.3 ± 3.4 cm, respectively, p = 0.034), but did not differ in weight (73.6 ± 5.2 kg vs. 70 ± 4.23 kg, respectively, p = 0.081), body mass index (BMI) (23.5 ± 1.13 vs. 24.1 ± 1.45, respectively, p = 0.060), and age (22 ± 1.11 vs. 23 ± 1.14 years, respectively, p = 0.2). Their stress responses were assessed through self-reported anxiety levels and physiological measurements of salivary cortisol concentrations and heart rate (HR). Results: For HR, significant effects of time (F(2,120) = 21.34, p < 0.001, η2 = 0.26) were found, but not for training status (F(1,60) = 2.69, p = 0.106, η2 = 0.04). For cortisol levels, the analysis showed the main effects of time (F(3,180) = 11.73, p < 0.001, η2 = 0.16) and training status (F(1,60) = 4.69, p = 0.034, η2 = 0.07) and a significant interaction between training status and time (F(3,180) = 3.07, p = 0.029, η2 = 0.05). Post-hoc analyses showed higher cortisol concentrations among volleyball players following the math task (all p < 0.001), as well as higher cortisol concentrations in S2, S3, and S4 compared to S1 in volleyball players (all p < 0.001). We observed also a significant increase in state anxiety in both groups (all p < 0.001), but no differences in state anxiety levels between groups. Conclusion: Female volleyball players may not differ in subjective graduation of stressors; however, exposure to training-based stressors seems to promote cortisol response to the anticipated stressor.

The Effect of Psychological Stress on Salivary Testosterone in Puberty Children

BACKGROUND

Psychological stress is a condition that is experienced by many adolescents which affect the Hypothalamic-Pituitary-Gonadal axis. Testosterone is known as a sex steroid hormone that is susceptible to acute stress and can be measured through saliva. Disruption of the reproductive system can affect the sexual maturation process.

AIM

To understand the difference in salivary testosterone levels in puberty children before and after given a stressor.

METHODS

A quasi-experimental intervention study was conducted at Antonius Bangun Mulia junior high school, Medan, North Sumatera, in July-October 2017. Subjects were students aged 12-14 years with sexual maturity G2 for boys and M2 for girls. Psychological stress intervention was generated by the Wechsler intelligence scale for children fourth edition (WISC IV). Saliva was collected before and after the intervention. The analysis was done with Wilcoxon test and a P value < 0.05 was considered significant.

RESULTS

Forty-two subjects of 24 male students and 18 female students with sexual maturation Tanner II (54.8%) and Tanner III (45.2%). This study obtained that there was a statistically significant difference in salivary testosterone levels before and after the subject was given a stressor (P = 0.015, CI 95%). This difference also was seen within sexual maturation Tanner II (P = 0.045, CI 95%). No difference was observed in testosterone levels based on gender, male students (P = 0.065, CI 95%) and female students (P = 0.112, CI 95%).

CONCLUSION

Stress can affect salivary testosterone levels. There was a statistically significant difference in salivary testosterone levels before and after psychological stress in puberty children.

Promoting physical activity in people with intellectual and multiple disabilities through a basic technology-aided program

This study assessed a technology-aided program (monitoring responding, and ensuring preferred stimulation and encouragements) for promoting physical activity with 11 participants with severe/profound intellectual and multiple disabilities. Each participant was provided with an exercise device (e.g. a static bicycle and a stepper) and exposed to the program according to an ABAB design, in which A and B represented baseline and intervention phases, respectively. Data recording concerned (a) the participants' responses with the exercise device (e.g. pedaling) during baseline and intervention phases and (b) their heart rates during the last intervention phase. The results showed that all participants had significant increases in responding with the exercise devices during the intervention phases. Heart-rate values during the intervention sessions indicated that the participants' responding during those sessions mostly amounted to moderate-intensity physical activity, with potential benefits for their overall physical condition. Implications of the findings and questions for future research in the area were discussed.

Measuring mental workload: ocular astigmatism aberration as a novel objective index

This study assessed the effect of two perceptually matched mental tasks with different levels of mental demand on ocular aberrations in a group of young adults. We measured ocular aberration with a wavefront sensor, and total, internal and corneal RMS (root mean square) aberrations were calculated from Zernike coefficients, considering natural and scaled pupils (5, 4.5, and 4 mm). We found that total, internal and corneal astigmatism RMS showed significant differences between mental tasks with natural pupils (p < .05), and this effect was maintained with 5 mm scaled pupils (total RMS astigmatism, p < .05). Consistently, pupil size, intraocular pressure, perceived mental load and cognitive performance were influenced by the level of mental complexity (p < .05 for all). The findings suggest that ocular astigmatism aberration, mediated by intraocular pressure, could be an objective, valid reliable index to evaluate the impact of cognitive processing in conjunction with others physiological markers in real world contexts. Practitioner Summary: The search continues for a valid, reliable, convenient method of measuring mental workload. In this study we found ocular astigmatism aberration is sensitive to the cumulative effect of mental effort. It shows promise of being a novel ocular index which may help to assess mental workload in real situations.

Salivary alpha-amylase and cortisol responsiveness to stress in first episode, drug-naïve patients with panic disorder

Reported findings on reactivity to stress of the sympathetic-adreno-medullar (SAM) and hypothalamic-pituitary-adrenal (HPA) systems in panic disorder (PD) are very variable. This inconsistency may be explained by differences in treatment exposure, illness duration and emotion regulation strategies. The present study examined the reactivity to mental stress of the SAM and HPA axes in a sample of first episode, drug naïve patients with PD which avoids confounds of medications exposure and illness chronicity. Activation of the SAM axis was evaluated by dosage of salivary alpha-amylase (sAA) and heart rate. Activation of the HPA axis was tested by dosage of salivary cortisol. Psychological assessments were done by the Self-Rating Depression Scale, the Self-Rating Anxiety Scale, the State-Trait Anxiety Inventory, the Cope Orientation to Problems Experienced (COPE) Inventory and the 16 Personality Factor Questionnaire (16PF). Patients showed reduced sAA stress reactivity, higher baseline cortisol levels and a more rapid decrease in stress cortisol levels as compared with controls. A significant correlation was found between active coping strategies and cortisol levels (response to stress). The findings suggest that blunted SAM stress reactivity and a rapid decrease in stress cortisol levels reflect traits that may enhance vulnerability to psychopathology in patients with PD.

Frontal Control Process in Intentional Forgetting: Electrophysiological Evidence

In this study, we aimed to seek for the neural evidence of the inhibition control process in directed forgetting (DF). We adopted a modified item-method DF paradigm, in which four kinds of cues were involved. In some trials, the words were followed by only a forgetting (F) cue. In the other trials, after a word was presented, a maintenance (M) cue was presented, followed by an explicit remembering (M-R) cue or an forgetting (M-F) cue. Data from 19 healthy adult participants showed that, (1) compared with the remembering cue (i.e., M-R cue), forgetting cues (i.e., M-F cue and F cue) evoked enhanced frontal N2 and reduced parietal P3 and late positive complex (LPC) components, indicating that the forgetting cues might trigger a more intensive cognitive control process and that fewer amounts of cognitive resources were recruited for the further rehearsal process. (2) Both the M cue and the F cue evoked enhanced N2 and decreased P3 and LPC components than the M-R or M-F cue. These results might indicate that compared with the M-R and M-F cues, both the M and F cues evoked a more intensive cognitive control process and decreased attentional resource allocation process. (3) The F cue evoked a decreased P2 component and an enhanced N2 component relative to the other cues (i.e., M-R, M-F, M), indicating that the F cue received fewer amounts of attentional resources and evoked a more intensive cognitive control process. Taken together, forgetting cues were associated with enhanced N2 activity relative to the maintenance rehearsal process or the remembering process, suggesting an enhanced cognitive control process under DF. This cognitive control process might reflect the role of inhibition in DF as attempting to suppress the ongoing encoding.

A cognitive stressor for event-related potential studies: the Portland arithmetic stress task

In this experiment, we developed and evaluated the Portland Arithmetic Stress Task (PAST) as a cognitive stressor to evaluate acute and sustained stress reactivity for event-related potential (ERP) studies. The PAST is a titrated arithmetic task adapted from the Montreal Imaging Stress Task (MIST), with added experimental control over presentation parameters, improved and synchronized acoustic feedback and generation of timing markers needed for physiological analyzes of real-time brain activity. Thirty-one older adults (M = 60 years) completed the PAST. EEG was recorded to assess feedback-related negativity (FRN) and the magnitude of the stress response through autonomic nervous system activity and salivary cortisol. Physiological measures other than EEG included heart rate, respiration rate, heart rate variability, blood pressure and salivary cortisol. These measures were collected at several time points throughout the task. Feedback-related negativity evoked-potential responses were elicited and they significantly differed depending on whether positive or negative feedback was received. The PAST also increased systolic blood pressure, heart rate variability and respiration rates compared to a control condition attentional task. These preliminary results suggest that the PAST is an effective cognitive stressor. Successful measurement of the feedback-related negativity suggests that the PAST is conducive to EEG and time-sensitive ERP experiments. Moreover, the physiological findings support the PAST as a potent method for inducing stress in older adult participants. Further research is needed to confirm these results, but the PAST shows promise as a tool for cognitive stress induction for time-locked event-related potential experiments.

Effect of acute psychological stress on response inhibition: An event-related potential study

This study aimed to investigate the effect of acute psychological stress on response inhibition and its electrophysiological correlates using a dual-task paradigm. Acute stress was induced by a primary task (mental arithmetic task), which consisted of a stress block and a control block. Response inhibition was measured using a secondary task (Go/NoGo task). In each trial, a Go/NoGo stimulus was presented immediately after the mental arithmetic task. The results revealed increased subjective stress and negative affect for the stress relative to control block, suggesting that the mental arithmetic task triggered a reliable stress response. ERPs locked to the Go/NoGo stimuli revealed that decreased P2 and increased N2 components were evoked for the stress block compared to the control block. These results demonstrated that acute psychological stress alters the response inhibition process by reducing the early selective attention process and enhancing the cognitive control process.