Cardiac vagal tone: a physiological index of stress

Role of stress and early-life stress in the pathogeny of inflammatory bowel disease

Numerous preclinical and clinical studies have shown that stress is one of the main environmental factor playing a significant role in the pathogeny and life-course of bowel diseases. However, stressful events that occur early in life, even during the fetal life, leave different traces within the central nervous system, in area involved in stress response and autonomic network but also in emotion, cognition and memory regulation. Early-life stress can disrupt the prefrontal-amygdala circuit thus favoring an imbalance of the autonomic nervous system and the hypothalamic-pituitary adrenal axis, resulting in anxiety-like behaviors. The down regulation of vagus nerve and cholinergic anti-inflammatory pathway favors pro-inflammatory conditions. Recent data suggest that emotional abuse at early life are aggravating risk factors in inflammatory bowel disease. This review aims to unravel the mechanisms that explain the consequences of early life events and stress in the pathophysiology of inflammatory bowel disease and their mental co-morbidities. A review of therapeutic potential will also be covered.

Respiratory Sinus Arrhythmia, Effortful Control, and Child Social Anxiety Symptoms

Emotion dysregulation is implicated in child social anxiety and its etiology. Child emotion dysregulation has been studied via physiological indicators (e.g., respiratory sinus arrhythmia [RSA]) and behavioral indicators (e.g., effortful control). Previous work suggests that physiological indicators of regulation may predict outcomes in a non-linear manner and must be considered within the context of other intrapersonal factors, perhaps including effortful control. To this end, the current study tested effortful control as a moderator of the relation between RSA and child social anxiety, considering both linear and curvilinear patterns and controlling for inhibited temperament, an established predictor of child anxiety. Children (n = 119; 44% female) participated when they were 4 years old and entering school age (5 to 7 years). Mothers reported on children's effortful control (age 4) and social anxiety (school age). Children's RSA (age 4) was calculated from electrocardiogram data when they were at rest (i.e., baseline RSA) and when they were giving a speech. Results indicated that when children were high in effortful control, lower baseline RSA predicted higher social anxiety symptoms. Tentative evidence emerged for a relation between greater suppression of RSA during the speech compared to baseline and higher social anxiety symptoms when children were low in effortful control. Results support assessing the temperamental domain of effortful control as a contextualizing factor in the relation between psychophysiology and child anxiety outcomes.

Recovery of heart rate and heart rate variability after a maximal cardiopulmonary exercise test in novice female runners

PURPOSE

Previous studies have shown delayed cardiac vagal reactivation after high-intensity endurance exercise when estimated with heart rate variability (HRV). However, the recovery dynamics of RR intervals (RRI) and HRV after a maximal incremental exercise test have been studied less in non-athletic population and especially in females. The main aim of the study was to examine the recovery dynamics of RRI and HRV immediately after a maximal cardiopulmonary exercise test (CPET) in adult females.

METHODS

Twenty-eight healthy, novice recreational female runners (33.7 ± 4.2 years) were selected to participate in this study from a larger group of participants (Run RCT). RRIs were collected continuously during a controlled rest, a CPET on a treadmill and a 15-min controlled, passive recovery. Minute-by-minute recovery dynamics were analyzed.

RESULTS

The dynamic phase of RRI and heart rate recovery (HRR) (from 192.2 ± 9.9 to 111.4 ± 2.4, P < 0.001) occurred during the first 4.5 min with HRR of 36 ± 10 beats during the first minute of the recovery. Resting heart rate was negatively associated (r =  - 0.53, P = 0.016) with HRR during the recovery. No recovery of root mean square of successive RRIs (RMSSD) was detected during the 15-min recovery. RMSSD was 15.0 ± 9.2% of resting values at the end of the recovery.

CONCLUSION

No recovery of vagal-derived HRV was detected immediately after a CPET in novice recreational female runners despite marked changes in sympathovagal balance, detected by rapid recovery of RRI during the first 5 min after exercise cessation.

Toward stressor-free stress estimation: The integrated information theory explains the information dynamics of stress

Recent neurological studies have revealed several detailed stress mechanisms. However, the latent variables behind stress study still interpret stress responses as difficult. Therefore, we propose a stressor-free method of stress evaluation using Integrated Information Theory (IIT) to address these issues. We conducted experiments inducing acute stress responses against tasks with three levels of difficulty, easy, moderate, and difficult, to verify the IIT in stress study. The moderate condition was related to active coping with stress. By contrast, the easy and difficult conditions are related to passive stress coping. Especially, the easy condition seemed to cause boredom. Our results revealed that the degree of entangled system fluctuation was associated with the subjective ratings for the tasks. Interestingly, our method could also evaluate stress as a state of boredom that had not received much research attention. Our method can be an alternative stress estimation method to overcome the latent variable problem.

Autonomic assessment at the intersection of psychosocial and gastrointestinal health

BACKGROUND

Wearable technology is increasingly used in clinical practice and research to monitor functional gastrointestinal symptoms and mental health.

AIMS

This article explores the potential of wearable sensors to enhance the understanding of the autonomic nervous system (ANS), particularly its role in linking psychological and gastrointestinal function. The ANS, facilitates brain-gut communication and is responsive to psychosocial conditions. It is implicated in disorders related to psychological stress and gut-brain interaction. Wearable technology enables tracking of the ANS in daily life, offering complementary and alternative methods from traditional lab-based measures. This review places focus on autonomic metrics such as respiratory sinus arrhythmia, vagal efficiency, and electrodermal activity as well as self-reports of autonomic symptoms.

DISCUSSION

Potential applications include use of wearable sensors for tracking autonomic activity in disorder of gut-brain interaction such as cyclic vomiting syndrome, in which ANS dysregulation may be triggered by psychosocial factors. Considerations for data interpretation and contextualization are addressed, acknowledging challenges such as situational confounders of ANS activity and accuracy of wearable devices.

When virtual reality becomes psychoneuroendocrine reality: A stress(or) review

This review article was awarded the Dirk Hellhammer award from ISPNE in 2023. It explores the dynamic relationship between stressors and stress from a historical view as well as a vision towards the future of stress research via virtual reality (VR). We introduce the concept of a "syncytium," a permeable boundary that blurs the distinction between stress and stressor, in order to understand why the field of stress biology continues to inadequately measure stress alone as a proxy for the force of external stressors. Using Virtual Reality (VR) as an illustrative example to explicate the black box of stressors, we examine the distinction between 'immersion' and 'presence' as analogous terms for stressor and stress, respectively. We argue that the conventional psychological approaches to stress measurement and appraisal theory unfortunately fall short in quantifying the force of the stressor, leading to reverse causality fallacies. Further, the concept of affordances is introduced as an ecological or holistic tool to measure and design a stressor's force, bridging the gap between the external environment and an individual's physiological response to stress. Affordances also serve to ameliorate shortcomings in stress appraisal by integrating ecological interdependencies. By combining VR and psychobiological measures, this paper aims to unravel the complexity of the stressor-stress syncytium, highlighting the necessity of assessing both the internal and external facets to gain a holistic understanding of stress physiology and shift away from reverse causality reasoning. We find that the utility of VR extends beyond presence to include affordance-based measures of immersion, which can effectively model stressor force. Future research should prioritize the development of tools that can measure both immersion and presence, thereby providing a more comprehensive understanding of how external stressors interact with individual psychological states.

A video-game-based method to induce states of high and low flow

Flow has been defined as a state of full immersion that may emerge when the skills of a person match the challenge of an activity. It is a special case of being on task, as during flow, keeping focused on the task feels effortless. Most experimental investigations of the neural or physiological correlates of flow contrast conditions with different levels of challenge. Yet comparing different levels of challenge that are too distant may trigger states where the participant is off task, such as boredom or frustration. Thus, it remains unclear whether previously observed differences ascribed to flow may rather reflect differences in how much participants were on task-trying their best-across the contrasted conditions. To remedy this, we introduce a method to manipulate flow by contrasting two video game play conditions at personalized levels of difficulty calibrated such that participants similarly tried their best in both conditions. Across three experiments (> 90 participants), higher flow was robustly reported in our high-flow than in our low-flow condition (mean effect size d = 1.31). Cardiac, respiratory, and skin conductance measures confirmed the known difference between a period of rest and the two on-task conditions of high and low flow, but failed to distinguish between these latter two. In light of the conflicting findings regarding the physiological correlates of flow, we discuss the importance of ensuring a low-flow baseline condition that maintains participants on task, and propose that the present method provides a methodological advance toward that goal.

Using Heart Rate Variability to Assess Nurses' Stress During the COVID-19 Pandemic

OBJECTIVE

This study aimed to assess subjective and objective parameters of stress among nurses during the COVID-19 pandemic and to examine the recovery effect of a day off.

METHODS

In this prospective observational trial, we measured heart rate variability (using a wearable device) and perceived stress levels on 3 working days and 1 day off. We obtained the following data using an online questionnaire: working conditions, COVID-19-related problems, depression (Patient Health Questionnaire-9), anxiety (Generalized Anxiety Disorder-7), effort-reward imbalance, and work-family conflict in a sample of German nurses (N = 41).

RESULTS

When comparing working days with a day off, we observed a significant difference for physical load (Cohen's d = 0.798, P < .001), mental load (Cohen's d = 0.660, P = .001), emotional exhaustion (Cohen's d = 0.945, P < .001), and overburdening (Cohen's d = 0.585, P = .002) with higher scores on working days. Regarding heart rate variability, we did not find a difference. Correlational analyses revealed a significant association between being afraid to get infected with COVID-19 and lower heart rate variability (r = -0.336, P = .045) and between being afraid to infect relatives and lower heart rate variability (r = -0.442, P = .007). Furthermore, a higher total sum score of work-family conflict was significantly associated with lower heart rate variability (r = -0.424, P = .01).

CONCLUSION

As heart rate variability observations were different from those regarding subjectively perceived stress, further studies are needed to evaluate and differentiate the influence of work stress and other types of stress on heart rate variability.

Proof of mechanism investigation of Transcutaneous auricular vagus nerve stimulation through simultaneous measurement of autonomic functions: a randomized controlled trial protocol

BACKGROUND

The autonomic nervous system plays a vital role in regulating physiological functions. Transcutaneous auricular vagus nerve stimulation (taVNS) is a method that provides insights into autonomic nerve modulation. This paper presents a research protocol investigating proof of mechanism for the impact of taVNS on autonomic functions and aims to both deepen theoretical understanding and pave the way for clinically relevant applications.

METHODS

This protocol employs a single-blind, randomized cross-over design involving 10 healthy male participants. Simultaneous assessment of both the afferent and efferent aspects of the vagus nerve will be performed by integrating physiological measures, magnetic resonance imaging, and a questionnaire survey. Electrocardiogram will be measured to assess changes in heart rate, as a primary outcome, and heart rate variability. Active taVNS and sham stimulation will be compared, which ensures precision and blinding. Electrical stimulation will be applied to the left concha cymba and the left lobule for the active and sham conditions, respectively. The specific parameters of taVNS involve a pulse width of 250 µs, a frequency of 25 Hz, and a current adjusted to the perception threshold (0.1 mA ≤ 5 mA), delivered in cycles of 32 s on and 28 s off.

CONCLUSIONS

This research investigates proof of mechanism for taVNS to elucidate its modulatory effects on the central and peripheral components of the autonomic nervous system. Beyond theoretical insights, the findings will provide a foundation for designing targeted neuromodulation strategies, potentially benefiting diverse patient populations experiencing autonomic dysregulation. By elucidating the neural mechanisms, this study contributes to the evolution of personalized and effective clinical interventions in the field of neuromodulation.

TRIAL REGISTRATION

JRCT, jRCTs032220332, Registered 13 September 2022; https://jrct.niph.go.jp/latest-detail/jRCTs032220332 .

When the body fosters empathy: The interconnectivity between bodily reactivity, meditation, and embodied abstract concepts

Empathy is a fundamental social ability that allows humans to infer others' emotions and intentions. Empathy is thought to be rooted in bodily sensations coming from the autonomic nervous system. In parallel, the functionality and perceptions coming from the autonomic nervous system could be improved by practicing activities that involve mind-body interactions, such as meditation. Furthermore, perceptions from the autonomic nervous system are thought to be important in the embodiment of abstract concepts. Consequently, in the current study, we collected data online from 581 participants and explored the associations between levels of empathy and (1) the practice of meditation, music, and sports; (2) the impact of self-report measures on bodily awareness and reactivity; and (3) the embodiment of abstract concepts in interoception. In line with previous studies, Meditators were found to have higher empathy scores than Non-Meditators. In addition, lower levels of autonomic reactivity in organs above the diaphragm were associated with higher empathy. Finally, we also observed that empathy was positively associated with interoceptive components of abstract concepts in those participants with high autonomic reactivity. Taken together, the results suggest that meditation practice and having low autonomic reactivity are associated with empathy, arguably through the downregulation of autonomic responses. Implications for mind-body interaction in meditation and its role in promoting empathy are discussed.

Heart rate variability and behavioral alterations during prepartum period in dairy cows as predictors of calving: a preliminary study

OBJECTIVE

Parturition is crucial for dams, their calves, and cow managers. The prediction of calving time, which assists cow managers to decide on the relocation of cows to maternity pens and necessity of human supervision, is a pivotal aspect of livestock farming. However, existing methods of predicting calving time in dairy cows based on hormonal changes and clinical symptoms are time-consuming and yield unreliable predictions. Accordingly, we investigated whether heart rate variability (HRV) which is a non-invasive assessment of autonomic nervous system (ANS) activity and behavior during the prepartum period would be useful for predicting calving time in dairy cows.

METHODS

Eight pregnant cows were surveilled under electrocardiogram and video recordings for HRV and behavioral analyses, respectively. HRV parameters in time and frequency domains were evaluated. A 24-h time budget was calculated for each of six types of behavior (standing and lying with or without rumination, sleeping, and eating).

RESULTS

Heart rate on calving day is considerably higher than those recorded on the days preceding calving. Low frequency power declined, whereas high frequency power escalated on the calving day compared to the period between 24 and 48 h before calving. The time budget for ruminating while lying decreased and that while standing increased markedly on the calving day compared to those allocated on the preceding days; nonetheless, the total time budget for ruminating did not differ during the prepartum period.

CONCLUSION

We elucidated the ANS activity and behavioral profiles during prepartum period. Our results confirm that HRV parameters and behavior are useful for predicting calving time, and interestingly indicate that the time budget for ruminating while standing (or lying) may serve as a valuable predictor of calving. Collectively, our findings lay the foundation for future investigations to determine other potential predictors and formulate an algorithm for predicting calving time.

The Influence of Kapalabhati on Working Memory and Phasic Heart Rate Variability

BACKGROUND

Cognitive communication abilities, such as working memory (WM), are vital for accomplishing daily activities and are also important for higher-order processes such as planning and problem-solving. The current study investigates the simultaneous effect of kapalabhati (KBH) on WM and phasic heart rate variability (HRV).

METHODS

Twenty participants who fulfilled the inclusion and exclusion criteria, with an average age of 23.65±3.07 years (mean±SD), were recruited for the study. Prior to data collection, the participants underwent a seven-day orientation to maintain uniformity in KBH practice. EKGs were assessed using a 16-channel polygraph system arranged in a standard limb lead II configuration. WM was assessed using E-Prime version 2.0 (Psychology Software Tools, Sharpsburg, PA, USA).

RESULTS

There was a significant increase in accuracy after the immediate KBH practice in all three conditions of the WM task (i.e., n-back task: 0-back, 1-back, and 2-back). However, there was also an increase in reaction time. Repeated measures ANOVA of HRV measures showed statistically significant changes in mean rhythm-to-rhythm (RR) intervals, heart rate (HR), number of adjacent N-N intervals over 50 milliseconds (NN50), percentage of successive normal sinus RR intervals greater than 50 milliseconds (pNN50 RR), low frequency (LF), and high frequency (HF), with HR, NN50, pNN50, LF, and HF all significant at p<0.001 and the LF/HF ratio significant at the p<0.01 level.

CONCLUSION

The results of the current study suggest that KBH practice can modulate vagal tone or parasympathetic activity and improve WM performance. Furthermore, the parasympathetic shift found in the present study may promote better cardioprotective health and longevity.

Relationship between Non-Invasive Brain Stimulation and Autonomic Nervous System

Non-invasive brain stimulation (NIBS) approaches have seen a rise in utilization in both clinical and basic neuroscience in recent years. Here, we concentrate on the two methods that have received the greatest research: transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS). Both approaches have yielded pertinent data regarding the cortical excitability in subjects in good health as well as pertinent advancements in the management of various clinical disorders. NIBS is a helpful method for comprehending the cortical control of the ANS. Previous research has shown that there are notable changes in muscular sympathetic nerve activity when the motor cortex is modulated. Furthermore, in NIBS investigations, the ANS has been employed more frequently as an outcome measure to comprehend the overall impacts of these methods, including their safety profile. Though there is ample proof that brain stimulation has autonomic effects on animals, new research on the connection between NIBS and the ANS has produced contradictory findings. In order to better understand NIBS processes and ANS function, it is crucial to take into account the reciprocal relationship that exists between central modulation and ANS function.

Social interaction anxiety and sleep quality in youth: Individual difference in childhood adversity and cardiac vagal control

BACKGROUND

Social interaction anxiety and sleep problems are prevalent during adolescence. Social interaction anxiety undermines sleep quality, however, little is known whether the association between social interaction anxiety and sleep quality is moderated by environmental factors such as childhood adversity and individual factors such as cardiac vagal control. This study sought to investigate the moderating effects of childhood adversity and cardiac vagal control on the link between social interaction anxiety and sleep quality.

METHOD

The Social Interaction Anxiety Scale, the Pittsburgh Sleep Quality Index and the Childhood Trauma Questionnaire were administered to 274 adolescents, who received 3-min resting ECG recording to assess respiratory sinus arrhythmia (RSA) as an index of cardiac vagal control.

RESULTS

Social interaction anxiety was negatively associated with sleep quality, and this association was moderated by childhood adversity and cardiac vagal control. In specific, social interaction anxiety was negatively associated with sleep quality among adolescents with low childhood adversity regardless of cardiac vagal control. Sleep quality was generally disrupted when adolescents exposed to high childhood adversity, but the negative association between social interaction anxiety and sleep quality among adolescents with high childhood adversity could be amortized by high cardiac vagal control.

LIMITATIONS

Cross-sectional design precluded establishing causality among variables.

CONCLUSION

These findings suggest that high cardiac vagal control reflecting better self-regulation might buffer the negative effect of social interaction anxiety on sleep quality particularly among adolescents exposed to early life stress.

Night time heart rate predicts next-day pain in fibromyalgia and primary back pain

Introduction

Primary chronic pain is pain that persists for over 3 months without associated measurable tissue damage. One of the most consistent findings in primary chronic pain is its association with autonomic hyperactivation. Yet whether the autonomic hyperactivation causes the pain or results from it is still unclear. It is also unclear to what extent autonomic hyperactivation is related to experienced pain intensity in different subtypes or primary chronic pain.

Objectives

Our first aim was to test lagged relationships between the markers of autonomic activation (heart rate) and pain intensity to determine its directionality. The main question here was whether autonomic biomarkers predict pain intensity or whether pain intensity predicts autonomic biomarkers. The second aim was to test whether this relationship is different between people with primary back pain and people with fibromyalgia.

Methods

Sixty-six patients with chronic pain were observed over an average of 81 days. Sleep heart rate and heart rate variability were measured with a wearable sensor, and pain intensity was assessed from daily subjective reports.

Results

The results showed a predictive relationship between sleep heart rate and next-day pain intensity (P < 0.05), but not between daily pain intensity and next night heart rate. There was no interaction with the type of chronic pain.

Conclusions

These findings suggest that autonomic hyperactivation, whether stress-driven or arising from other causes, precedes increases in primary chronic pain. Moreover, the present results suggest that autonomic hyperactivation is a common mechanism underlying the pain experience in fibromyalgia and chronic back pain.

Using caffeine as a chemical means to induce flow states

Flow is an intrinsically rewarding state characterised by positive affect and total task absorption. Because cognitive and physical performance are optimal in flow, chemical means to facilitate this state are appealing. Caffeine, a non-selective adenosine receptor antagonist, has been emphasized as a potential flow-inducer. Thus, we review the psychological and biological effects of caffeine that, conceptually, enhance flow. Caffeine may facilitate flow through various effects, including: i) upregulation of dopamine D1/D2 receptor affinity in reward-associated brain areas, leading to greater energetic arousal and 'wanting'; ii) protection of dopaminergic neurons; iii) increases in norepinephrine release and alertness, which offset sleep-deprivation and hypoarousal; iv) heightening of parasympathetic high frequency heart rate variability, resulting in improved cortical stress appraisal, v) modification of striatal endocannabinoid-CB1 receptor-signalling, leading to enhanced stress tolerance; and vi) changes in brain network activity in favour of executive function and flow. We also discuss the application of caffeine to treat attention deficit hyperactivity disorder and caveats. We hope to inspire studies assessing the use of caffeine to induce flow.

Mechanisms for survival: vagal control of goal-directed behavior

Survival is a fundamental physiological drive, and neural circuits have evolved to prioritize actions that meet the energy demands of the body. This fine-tuning of goal-directed actions based on metabolic states ('allostasis') is deeply rooted in our brain, and hindbrain nuclei orchestrate the vital communication between the brain and body through the vagus nerve. Despite mounting evidence for vagal control of allostatic behavior in animals, its broader function in humans is still contested. Based on stimulation studies, we propose that the vagal afferent pathway supports transitions between survival modes by gating the integration of ascending bodily signals, thereby regulating reward-seeking. By reconceptualizing vagal signals as catalysts for goal-directed behavior, our perspective opens new avenues for theory-driven translational work in mental disorders.

Perceived Parenting Stress Is Related to Cardiac Flexibility in Mothers: Data from the NorBaby Study

Heart rate variability (HRV) is an indicator of autonomic nervous system activity, and high levels of stress and/or depressive symptoms may reduce HRV. Here, we assessed whether (a) parental stress affected HRV in mothers during the perinatal period and whether this is mediated by bonding and (b) whether antenatal maternal mental states, specifically repetitive negative thinking, depressive symptoms, and pregnancy-related anxiety, have an impact on infant HRV, and lastly, we investigated (c) the relationship between maternal HRV and infant HRV. Data are from the Northern Babies Longitudinal Study (NorBaby). In 111 parent-infant pairs, cardiac data were collected 6 months after birth. In the antenatal period, we used the Pregnancy-Related Anxiety Questionnaire-Revised, the Edinburgh Postnatal Depression Scale, and the Perseverative Thinking Questionnaire; in the postnatal period, we used the Parenting Stress Index and the Maternal Postnatal Attachment Scale. Higher levels of perceived parenting stress but not depressive symptoms were associated with lower HRV in mothers (τ = -0.146), and this relationship was not mediated by maternal bonding. Antenatal maternal mental states were not associated with infant HRV. There was no significant correlation between maternal HRV and infant HRV. Our observational data suggest that perceived stress reduces cardiac flexibility. Future studies should measure HRV and parenting stress repeatedly during the perinatal period.

Parents' depressive symptoms and reflective functioning predict parents' proficiency in relational savoring and children's physiological regulation

This study examined parental depression and parental reflective functioning (PRF) as predictors of parental proficiency in relational savoring (RS), the association between RS proficiency and a marker of children's physiological self-regulation, respiratory sinus arrhythmia (RSA), during a stressor, and indirect effects of parental depression and PRF on children's RSA via parents' RS. At Time 1 (T1), parents of 8- to 12-year-old children (N = 139) reported on their depressive symptoms and completed a parenting interview, coded for PRF. After 1.5 years (Time 2; T2), parents savored a positive relational memory that involved their children, which was coded for savoring proficiency. Children's RSA was measured during a stressful task (a series of impossible puzzles). Depressive symptoms (inversely) and PRF (positively) were associated with RS proficiency. Higher parental RS proficiency was associated with children's higher mean levels of RSA during the stressor. Indirect effects models supported that T2 RS proficiency mediated the negative association between parental T1 depressive symptoms and children's T2 RSA, and between T1 PRF and children's T2 RSA. We discuss these findings in terms of implications for parents' emotion regulation, children's emotion regulation, children's mental health, and intervention.

Preliminary Technical Validation of LittleBeats™: A Multimodal Sensing Platform to Capture Cardiac Physiology, Motion, and Vocalizations

Across five studies, we present the preliminary technical validation of an infant-wearable platform, LittleBeats™, that integrates electrocardiogram (ECG), inertial measurement unit (IMU), and audio sensors. Each sensor modality is validated against data from gold-standard equipment using established algorithms and laboratory tasks. Interbeat interval (IBI) data obtained from the LittleBeats™ ECG sensor indicate acceptable mean absolute percent error rates for both adults (Study 1, N = 16) and infants (Study 2, N = 5) across low- and high-challenge sessions and expected patterns of change in respiratory sinus arrythmia (RSA). For automated activity recognition (upright vs. walk vs. glide vs. squat) using accelerometer data from the LittleBeats™ IMU (Study 3, N = 12 adults), performance was good to excellent, with smartphone (industry standard) data outperforming LittleBeats™ by less than 4 percentage points. Speech emotion recognition (Study 4, N = 8 adults) applied to LittleBeats™ versus smartphone audio data indicated a comparable performance, with no significant difference in error rates. On an automatic speech recognition task (Study 5, N = 12 adults), the best performing algorithm yielded relatively low word error rates, although LittleBeats™ (4.16%) versus smartphone (2.73%) error rates were somewhat higher. Together, these validation studies indicate that LittleBeats™ sensors yield a data quality that is largely comparable to those obtained from gold-standard devices and established protocols used in prior research.

Effect of wrist orthoses on upper limb function, activities of daily living, and stress response

Introduction

This study examined the effects on upper limb function, activities of daily living, and stress responses when wearing a wrist orthosis made of padded fiberglass or thermoplastic and provided essential information for selecting an orthosis.

Methods

Thirty-one healthy adults performed two tests while not wearing a wrist orthosis, wearing a padded fiberglass wrist orthosis, and wearing a thermoplastic wrist orthosis. The Purdue Pegboard Test examined upper limb control. In the second test, the actions indicated by the Hand20 questionnaire were performed while wearing a wrist orthosis. An electrocardiogram was obtained before and after each test to identify any changes in sympathetic nervous system activity.

Results

The Purdue Pegboard Test scores were significantly higher when not wearing a wrist orthosis than when wearing wrist orthosis, and the Hand20 scores for all question were significantly lower. Thermoplastic wrist orthoses had fewer restrictions for upper limb function compared to padded fiberglass wrist orthoses, however activities of daily living were more limited. The low frequency/high frequency ratio and high frequency measures showed no significant differences.

Conclusions

Pegboard test scores and the Hand 20 scores suggest that a wrist orthosis causes restriction of upper limb function.

Exploring the efficacy of sense of Okayness (SOK) as an antidote for stress in older adults: the role of SOK elevation intervention, heart rate variability (HRV), and cognitive performance in stressful and relaxing situations

Sense of Okayness (SOK) is an emerging concept that describes a person's ability to remain stable and unshaken in the face of life transitions and hardships. This quality enables effective stress regulation and heightened tolerance to uncertainty. To investigate the possible role of the parasympathetic nervous system (PNS) in mediating the relationship between SOK and stress regulation among older individuals, an analytical sample of N  =  69 participants (74% women) with a mean age of 78.75 years (SD age  =  6.78) was recruited for a standardized cognitive assessment and stress induction. Baseline heart rate variability (HRV), measured via electrocardiogram (ECG), and SOK assessments were conducted prior to stress induction, along with a baseline cognitive evaluation. Subsequently, participants were subjected to a psychosocial stress paradigm, followed by either a 30-minute SOK elevation intervention (n = 40) or a control condition with nature sounds (n = 29). A second cognitive assessment was administered post-intervention, with continuous HRV measurement through ECG. The results revealed significant HRV changes due to the experimental intervention, though no significant differences were observed between the SOK intervention and control groups. Interestingly, individuals with high trait SOK displayed more stable HRV trajectories, exhibiting a smaller decline during the stress intervention and a milder increase during both the stressor and SOK intervention phases. Overall, these findings do suggest a significant association between SOK, parasympathetic activity, and stress reactivity. These results prompt further investigation into whether personality patterns, such as a strong SOK, may be linked to reduced vagal reactivity and better coping in old age.

Association of Self-Reported Autonomic Symptoms With Sensor-Based Physiological Measures

OBJECTIVE

Autonomic regulation of organ and tissues may give rise to disruptions of typical functions. The Body Perception Questionnaire Short Form (BPQ-SF) includes items that were developed to assess autonomic symptoms in daily life. This pair of studies aimed to establish previously unexplored psychometric properties of the BPQ-SF autonomic symptoms scale, develop normative values for clinical and research use, and assess the convergence of self-reports with sensor-based measures.

METHODS

Study 1 reports exploratory and confirmatory factor analysis on BPQ-SF autonomic symptom items from a large US population-based online study ( n = 2048). In study 2, BPQ-SF scores were examined for associations with heart period, respiratory sinus arrhythmia, and skin conductance during seated leg lifts in a community sample ( n = 62).

RESULTS

Study 1 results supported a two-factor supradiaphragmatic and subdiaphragmatic autonomic symptom solution (confirmatory factor analysis: root mean squared error of approximation = 0.040, Comparative Fit Index = 0.99, Tucker-Lewis Index = 0.99), although a one-factor solution also fit the data well (root mean squared error of approximation = 0.080, Comparative Fit Index = 0.99, Tucker-Lewis Index = 0.99). In study 2, heart period responses to leg lifts and rests were demonstrated at all autonomic symptom levels. However, low autonomic symptoms were associated with optimal autonomic nervous system patterns of activation and recovery to baseline levels. Moderate symptoms were associated with prolonged sympathetic activation. The highest symptom levels were associated with impaired autonomic nervous system coordination across activation and recovery.

CONCLUSIONS

Results support the utility of self-reports of autonomic symptoms in research and clinical applications, with higher symptoms likely indicating autonomic impairment.

Reducing Stress and Anxiety in First-Year Undergraduates Through Biofeedback-Assisted Relaxation Training

Background: College students face many stressors daily, often resulting in psychological challenges such as heightened anxiety and depression. Biofeedback is becoming aware of and learning to modify the body's physiological functions. This study aimed to evaluate the efficacy of biofeedback relaxation training in mitigating stress and anxiety levels among medical undergraduates. Methods: This pretest-posttest control group design study was conducted following the ethics committee's approval. The study selected first-year MBBS students based on their elevated stress and anxiety scores and divided them into intervention and control groups. The study involved subjecting the intervention group to 10 sessions of biofeedback relaxation training, while the control group was not given any treatment. Stress and anxiety levels were assessed before and after the intervention of 10 to 12 weeks using the Perceived Stress Scale-14 and Cognitive Test Anxiety Scale. Results: The study involved 93 students, with 47 of them in the intervention group and the remaining 46 in the control group. After biofeedback, the intervention group showed significantly lower stress and anxiety scores than the control group. Conclusion: Biofeedback training effectively reduced stress and anxiety levels among undergraduate medical students. Biofeedback techniques can be implemented in college settings to support student mental wellness.

Pilot study shows skin-to-skin care with parents improves heart rate variability in preterm infants in the neonatal intensive care unit

Background

Skin-to-skin care in the newborn intensive care unit typically lasts for short periods of time and enhances breastfeeding, attachment, and parental self-esteem. Heart rate variability (HRV) increases with gestational age and is a measure of maturation of parasympathetic vs. sympathetic autonomic nervous system activity. HRV measurements may be useful in capturing changes in autonomic regulation in response to skin-to-skin care.

Objective

To analyze the effects of skin-to-skin care on HRV in preterm infants receiving respiratory support. We hypothesized that skin-to-skin care would result in a more mature pattern of parasympathetic activity.

Methods

In this prospective crossover study, infants <30 weeks' gestation and 1-6 weeks postnatal age had HRV recorded for 30 min before, during, and after skin-to-skin care sessions. HRV characteristics analyzed included the standard deviation of the normal-to-normal interval (SDNN), the root mean squared of successive differences of normal-to-normal intervals (RMSSD), and the standard deviation of decelerations (SDDec).

Results

10 infants between 25 5/7-29 6/7 weeks gestational age and 7-41 days postnatal age completed 22 sessions while receiving respiratory support (positive pressure ventilation or nasal cannula oxygen). Two measures of HRV (SDNN and RMSSD) were significantly decreased by the end of the skin-to-skin sessions, compared to pre-session values. SDNN decreased from a median of 10.44 ms before the session to 6.70 ms after being placed back in bed (p < 0.05), with RMSSD decreasing from a median of 6.80 ms before the session to 4.32 ms while being held at the end of 30 min (p < 0.05).

Discussion

Skin-to-skin care with a parent resulted in a more mature autonomic nervous system pattern in preterm infants receiving respiratory support, suggesting physiologic benefit for the infant. No adverse events were seen during any session.

The Potential of Heart Rate Variability Monitoring for Mental Health Assessment in Top Wheel Gymnastics Athletes: A Single Case Design

The assessment of heart rate variability (HRV) upon waking has been proposed as a method to evaluate mental health; however, owing to large individual differences among athletes, it is unclear whether HRV is adequate to predict mental health decline. In this study, we sought to establish this by evaluating HRV upon awakening in one athlete over 20 months. We assessed mental health once a month by calculating the depression index. In addition, self-reported training load and psychological fatigue index were assessed as psychological indices for athletes. Heart rate and HRV were each measured three days per week in both resting (supine) and standing (upright) positions. The results showed that orthostatic HRV upon waking had moderate linear relationships with the scores on the depression index and psychological fatigue index. By contrast, self-reported training load, a measure of physical stressor, was not associated with HRV. The findings suggest that the repeated assessment of HRV upon waking and mental health indicators may be useful in preventing mental health decline in athletes.

Transcutaneous Auricular Vagus Nerve Stimulation Attenuates Early Increases in Heart Rate Associated With the Cold Pressor Test

INTRODUCTION

Transcutaneous auricular vagus nerve stimulation (taVNS) may be useful in treating disorders characterized by chronic parasympathetic disinhibition. Acute taVNS decreases resting heart rate in healthy individuals, but little is known regarding the effects of taVNS on the cardiac response to an acute stressor. To investigate effects on the acute stress response, we investigated how taVNS affected heart rate changes during a cold pressor test (CPT), a validated stress induction technique that reliably elicits a sympathetic stress response with marked increases in heart rate, anxiety, stress, and pain.

MATERIALS AND METHODS

We recruited 24 healthy adults (ten women, mean age = 29 years) to participate in this randomized, crossover, exploratory trial. Each subject completed two taVNS treatments (one active, one sham) paired with CPTs in the same session. Order of active versus sham stimulation was randomized. Heart rate, along with ratings of anxiety, stress, and pain, was collected before, during, and after each round of taVNS/sham + CPT.

RESULTS

In both stimulation conditions, heart rate was elevated from baseline in response to the CPT. Analyses also revealed a difference between active and sham taVNS during the first 40 seconds of the CPT (Δ heart rate [HR] = 12.75 ± 7.85 in the active condition; Δ HR = 16.09 ± 11.43 in the sham condition, p = 0.044). There were no significant differences in subjective ratings between active and sham taVNS.

CONCLUSIONS

In this randomized, sham-controlled study, taVNS attenuated initial increases in HR in response to the CPT. Future studies are needed to investigate the effects of various taVNS doses and parameters on the CPT, in addition to other forms of stress induction.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT00113453.

Home-Based Dynamics of Sleepiness-Related Conditions Starting at Biological Evening and Later (Beyond Working)

Shift work requires round-the-clock readiness to perform professional duties, and the workers' performance highly depends on their sleepiness level, which can be underestimated during a shift. Various factors, including the time of day, can influence sleepiness in shift workers. The objective of this study was to explore the dynamics of sleepiness-related conditions assessed through heart rate variability analysis, starting from the biological evening and continuing in vivo (at home), without the need for artificial alertness support. The participants solely performed regular evening household duties. A total of 32 recordings were collected from the Subjective Sleepiness Dynamics Dataset for analysis. At 8:00 p.m. and every 30 min thereafter, the participants completed cyclic sleepiness scales (the KSS and the SSS) until the time they went to bed, while their heart rate was recorded. The results of the study indicated that during the biological evening, high sleepiness is associated with a 'stressed' condition characterized by higher sympathetic activation. Later on, it is associated with a 'drowsy' condition characterized by higher parasympathetic activation and a decline in heart rate variability. Our findings provide evidence that the type of condition experienced during high sleepiness depends on the biological time. This should be taken into account when managing work regimes in shift work and developing alertness detectors.

Coregulation: A Multilevel Approach via Biology and Behavior

In this article, we explore the concept of coregulation, which encompasses the mutual adaptation between partners in response to one another's biology and behavior. Coregulation operates at both biological (hormonal and nervous system) and behavioral (affective and cognitive) levels and plays a crucial role in the development of self-regulation. Coregulation extends beyond the actions of individuals in a dyad and involves interactive contributions of both partners. We use as an example parent-child coregulation, which is pervasive and expected, as it emerges from shared genetic relatedness, cohabitation, continuous interaction, and the influence of common factors like culture, which facilitate interpersonal coregulation. We also highlight the emerging field of neural attunement, which investigates the coordination of brain-based neural activities between individuals, particularly in social interactions. Understanding the mechanisms and significance of neural attunement adds a new dimension to our understanding of coregulation and its implications for parent-child relationships and child development.

Growth mindset and school burnout symptoms in young adolescents: the role of vagal activity as potential mediator

Experiencing school burnout symptoms can have negative consequences for learning. A growth mindset, the belief that human qualities such as intelligence are malleable, has previously been correlated with fewer school burnout symptoms in late adolescents. This might be because adolescents with a stronger growth mindset show more adaptive self-regulation strategies and thereby increasing resilience against academic setbacks. Here we confirmed in a sample of 426 Dutch young adolescents (11-14 years old; 48% female) that this relationship between growth mindset and school burnout symptoms holds after controlling for other potential predictors of school burnout symptoms such as academic achievement, school track, gender, and socio-economic status. Our second aim was to increase our understanding of the mechanism underlying the relation between mindset and school burnout, by measuring physiological resilience (vagal activity, a measure of parasympathetic activity, also known as heart rate variability or HRV) in a subsample (n = 50). We did not find any relation between vagal activity and growth mindset or school burnout symptoms, nor could we establish a mediating effect of vagal activity in their relation. In conclusion, we found evidence for a potential protective effect of a growth mindset on school burnout symptoms in young adolescents, but not for physiological resilience (vagal activity) as an underlying mechanism. The protective effect of growth mindset as confirmed in our younger sample can be leveraged in interventions to prevent increasing school burnout symptoms.

The within-person association of relative left frontal activity and vagally mediated heart rate variability not moderated by history of depression

Motivated by the Neurovisceral Integration Model (NVI) of cardiac vagal control, we investigated the relationship between relative left frontal activity (rLFA) and vagally mediated heart rate variability or respiratory sinus arrhythmia (RSA) in 287 participants, half of whom had a history of depression. We hypothesized that there would be a within-person association of rLFA and RSA such that when RSA is lower rLFA would also be lower (Hypothesis I). Moreover, it was hypothesized that this within-subject association would be moderated by a history of depression (Hypothesis II). Metrics of rLFA and RSA were derived from concurrent electroencephalogram and electrocardiogram recordings. The logarithmic difference in EEG alpha power between the homologous right and left electrodes (Ln (Right/Left)) in the frontal region was used to index rLFA. A Hilbert transform was applied to the mean-centered and bandpass-filtered (0.12-.40 Hz) inter-beat interval (IBI) time series to get a fine-grained measure (in the time domain) of RSA. A linear mixed ANOVA model with rLFA as the dependent variable and RSA as the main fixed effect found that participants had less rLFA during epochs when they had lower RSA, which was consistent with the prediction from Hypothesis I. Contrary to the prediction from Hypothesis II, the within-person association of RSA and rLFA was not moderated by a history of depression. However, the association between RSA and rLFA varied across the four pairs of frontal electrodes that we examined. Thus, more research is needed to determine the spatial extent of this association, e.g., examining the relationship between source-localized rLFA and RSA.

Autonomic indices and loss-of-control eating in adolescents: an ecological momentary assessment study

BACKGROUND

Loss-of-control (LOC) eating commonly develops during adolescence, and it predicts full-syndrome eating disorders and excess weight gain. Although negative emotions and emotion dysregulation are hypothesized to precede and predict LOC eating, they are rarely examined outside the self-report domain. Autonomic indices, including heart rate (HR) and heart rate variability (HRV), may provide information about stress and capacity for emotion regulation in response to stress.

METHODS

We studied whether autonomic indices predict LOC eating in real-time in adolescents with LOC eating and body mass index (BMI) ⩾70th percentile. Twenty-four adolescents aged 12-18 (67% female; BMI percentile mean ± standard deviation = 92.6 ± 9.4) who reported at least twice-monthly LOC episodes wore biosensors to monitor HR, HRV, and physical activity for 1 week. They reported their degree of LOC after all eating episodes on a visual analog scale (0-100) using a smartphone.

RESULTS

Adjusting for physical activity and time of day, higher HR and lower HRV predicted higher self-reported LOC after eating. Parsing between- and within-subjects effects, there was a significant, positive, within-subjects association between pre-meal HR and post-meal LOC rating. However, there was no significant within-subjects effect for HRV, nor were there between-subjects effects for either electrophysiologic variable.

CONCLUSIONS

Findings suggest that autonomic indices may either be a marker of risk for subsequent LOC eating or contribute to LOC eating. Linking physiological markers with behavior in the natural environment can improve knowledge of illness mechanisms and provide new avenues for intervention.

Sensory processing, autonomic nervous function, and social participation in people with mental illnesses

Introduction

This study investigated the relationship between sensory processing, respiratory sinus arrhythmia, and social participation in people with psychiatric disorders.

Method

This study recruited 30 participants, primarily women, from a psychiatric university hospital with a mental health diagnosis listed in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (mean age: 37.7 ± 16.0 years). Sensory processing, autonomic nervous function, and social participation were measured using the Adolescent/Adult Sensory Profile®, respiratory sinus arrhythmia, and World Health Organization Disability Assessment Schedule, respectively. Through mediation analysis, a model wherein sensory processing mediated the relationship between respiratory sinus arrhythmia and social participation was developed.

Results

Social participation was moderately to highly correlated with Adolescent/Adult Sensory Profile® quadrants (excluding sensory seeking) and respiratory sinus arrhythmia. Furthermore, the mediation analysis revealed that sensory avoiding mediated the relationship between respiratory sinus arrhythmia and social participation, consequently counteracting the direct relationship.

Conclusion

A mediation model was constructed, which indicated that individuals with psychiatric disorders and low parasympathetic nervous system activity expressed higher sensory processing quadrant of sensory avoiding. Ultimately, this was associated with reduced social participation.

Investigating the effectiveness of a smart mental health intervention (inMind) for stress reduction during pharmacological treatment for mild to moderate major depressive disorders: Study protocol for a randomized control trial

Background

Although psychological interventions for stress relief, such as cognitive behavioral therapy (CBT) and mindfulness-based stress reduction (MBSR), have been developed, they have not been widely used in treating depression. The use of mobile devices can increase the possibility of actual use by integrating interventions and reducing the difficulty and cost burden of treatment application. This study aims to determine whether "inMind," an integrated mobile application for stress reduction, developed for the general population, decreases stress for patients with mild to moderate major depressive disorder during the pharmacological treatment period.

Methods

This study is a single-blind, multicenter, randomized, controlled crossover trial. The App, developed in Republic of Korea, provides integrated interventions for stress reduction for the general population through three modules based on mindfulness-based stress reduction, cognitive behavior therapy, and relaxation sounds that are known to be effective in stress reduction ("meditation," "cognitive approach," and "relaxation sounds," respectively). Participants (n = 215) recruited via medical practitioner referral will be randomized to an App first group (fAPP) or a wait list crossover group (dAPP). The study will be conducted over 8 weeks; the fAPP group will use the App for the first 4 weeks and the dAPP group for the next 4 weeks. During all study periods, participants will receive their usual pharmacological treatment. The Depression Anxiety Stress Scale-21 is the primary outcome measure. The analysis will employ repeated measurements using a mixed-model approach.

Discussion

The App can potentially be an important addition to depression treatment because of its applicability and the comprehensive nature of the interventions that covers diverse stress-relieving models.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT05312203, identifier 2021GR0585.

The physiology of intraoperative error: using electrokardiograms to understand operator performance during robot-assisted surgery simulations

BACKGROUND

No platform for objective, synchronous and on-line evaluation of both intraoperative error and surgeon physiology yet exists. Electrokardiogram (EKG) metrics have been associated with cognitive and affective features that are known to impact surgical performance but have not yet been analyzed in conjunction with real-time error signals using objective, real-time methods.

METHODS

EKGs and operating console point-of-views (POVs) for fifteen general surgery residents and five non-medically trained participants were captured during three simulated robotic-assisted surgery (RAS) procedures. Time and frequency-domain EKG statistics were extracted from recorded EKGs. Intraoperative errors were detected from operating console POV videos. EKG statistics were synchronized with intraoperative error signals.

RESULTS

Relative to personalized baselines, IBI, SDNN and RMSSD decreased 0.15% (S.E. 3.603e-04; P = 3.25e-05), 3.08% (S.E. 1.603e-03; P < 2e-16) and 1.19% (S.E. 2.631e-03; P = 5.66e-06), respectively, during error. Relative LF RMS power decreased 1.44% (S.E. 2.337e-03; P = 8.38e-10), and relative HF RMS power increased 5.51% (S.E. 1.945e-03; P < 2e-16).

CONCLUSIONS

Use of a novel, on-line biometric and operating room data capture and analysis platform enabled detection of distinct operator physiological changes during intraoperative errors. Monitoring operator EKG metrics during surgery may help improve patient outcomes through real-time assessments of intraoperative surgical proficiency and perceived difficulty as well as inform personalized surgical skills development.

Effect of COVID-19 on Stress and Biomarkers: An Exploratory Cross-Sectional Study

Background Anxiety and stress in COVID-19 lead to continual pro-inflammatory cytokine activity resulting in excessive inflammation. Levels of different bio indices of COVID-19 may predict clinical outcomes and the severity of COVID-19 disease and may correlate with anxiety and stress levels. Objectives To measure the level of anxiety in COVID-19 patients using the coronavirus anxiety scale (CAS) as an assessment of psychological stress. To measure the levels of blood biomarkers and biochemical and hematological markers of inflammation in COVID-19. To record and measure the indices of short-term HRV in COVID-19 patients to assess their physiological and psychological stress levels. To determine the relationship between anxiety scores, levels of laboratory indices (blood biomarkers), and HRV parameters across mild, moderate and severe cases of COVID-19. Material and method A total of 300 COVID-19 patients aged between 18 and 55 years were included. A questionnaire-based CAS was used to assess anxiety levels. Short-term HRV was recorded to measure stress. Blood biomarkers: Biochemical and hemato-cytological markers of inflammation were measured. Statistical analyses were performed using the SPSS software version 20.0. Results Anxiety and stress increased with the severity of COVID-19. A positive correlation was detected between anxiety and serum ferritin, IL-6, MCV, and MCH levels, and a negative correlation between the corona anxiety score and RBC count. The increase in the severity of COVID-19 showed elevated levels of WBC count, neutrophil%, platelet count, neutrophil/lymphocyte ratio, serum ferritin, D-dimer, C-reactive protein, procalcitonin, interleukin-6, and lactate dehydrogenase, and decreased lymphocyte and monocyte percentages. The increase in the severity of COVID-19 decreased lymphocyte, monocyte, and eosinophil counts. Conclusion The Corona Anxiety Scale and heart rate variability can be used as complementary tools to index COVID-19-related anxiety and stress. An association exists between immune dysregulation and heart rate variability, which can be used to predict the inflammatory response and prognosis of COVID-19.

An Examination of Cardiac Vagal Control Indices and Cognitive Stress Appraisal in Cigarette Smokers

Identifying factors that influence how individuals who smoke cigarettes respond to stress is important as stress is a risk factor for smoking and its maintenance. This study examined the modulatory role of cardiac vagal control (CVC), a physiological correlate of self-regulation, on cognitive stress appraisal processes of adults who smoke. Sixty daily cigarette smokers were randomized to receive positive or negative feedback during a modified Trier Social Stress Test. Pre- and post-task stress appraisals were assessed and resting and reactivity CVC measures were computed. Moderated regression models assessed if the relation between feedback condition and post-task stress appraisal varied as a function of CVC. We hypothesized that participants receiving negative feedback would report greater post-task stress appraisal compared to participants receiving positive feedback, and the strength of the effect of both feedback groups would be greater at higher levels of CVC. All models showed significant main effects of feedback condition (b =  - 0.42, p = 0.01; b =  - 0.45, p = 0.01) on post-task stress appraisal: participants receiving negative feedback reported greater post-task stress appraisal. No significant main or interactive effects of CVC and feedback condition on post-task stress appraisal were observed. This study demonstrates that stress appraisals of daily cigarette smokers are sensitive to social feedback, but are not moderated by individual differences in CVC. Future investigations are needed to clarify whether this finding is explained by smoking-specific impairments in CVC as well as the distinct and interactive effects of physiological and psychological processes implicated in stress and smoking risk.

Differential Momentary Reports of Stress and Affect Associated With Alcohol Consumption in Middle-Aged Versus Younger Adults

Background: Stress is a motivator to consume alcohol, a well-documented relapse risk, and is known to differentially affect biological and psychological processes as people age.Objectives: Because alcohol consumption is known to acutely decrease stress and increase affect, this study examined differences in ratings of stress and affect in middle-aged versus younger adults who regularly consume alcohol.Methods: A sample of younger (n = 17) and middle-aged (n = 18) drinkers was studied during a 3-day period of typical alcohol consumption. Resting levels of respiratory sinus arrhythmia (RSA) were measured during a baseline study visit since RSA is a well-documented biomarker of stress and is known to decrease with age. Ecological momentary assessment (EMA) survey ratings (n = 1,598) were modeled using hierarchical regression to assess differences in stress and affect throughout the day between the two age groups.Results: As anticipated, middle-aged participants had lower RSA than those who were younger. Although the middle-aged adults showed overall lower stress, generally they also experienced higher affect than the younger adults. Middle-aged adults experienced a significant reduction in stress following drinking while no such effect was observed in the younger adults.Conclusions: To our knowledge, this is the first investigation using EMA methodology to examine stress and affect between younger and middle-aged adults who habitually consume alcohol. These cross-sectional data suggest potential momentary stress relief to engaging with moderate alcohol consumption in a middle-aged population. Future work must address this important motivational process in curtailing maintenance of alcohol consumption and preventing escalation of consumption.

Factor Structure and Clinical Correlates of The Dissociative Symptoms Scale (DSS) Korean Version Among Community Sample With Adverse Childhood Experiences

This study examined the factor structure and psychometric properties of the Dissociative Symptoms Scale (DSS) among the Korean community adult population with adverse childhood experiences (ACE). Data were drawn from community sample data sets collected from an online panel investigating the impact of ACE and ultimately consisted of data from a total of 1304 participants. A confirmatory factor analysis revealed a bi-factor model with a general factor and four sub-factors such as depersonalization/derealization, gaps in awareness and memory, sensory misperceptions, and cognitive behavioral reexperiencing, which are the four factors that correspond to the original DSS. The DSS showed good internal consistency as well as convergent validity with clinical correlates such as posttraumatic stress disorder, somatoform dissociation, and emotion dysregulation. The high-risk group with more ACE was associated with increased DSS. These findings support the multidimensionality of dissociation and the validity of Korean DSS scores in a general population sample.

Cardiac Vagal Control Among Community Cigarette Smokers with Low to Moderate Depressive Symptoms

Impairments in cardiac vagal control (CVC) have been independently linked to smoking status and depression and are implicated in self-regulatory processes that may exacerbate depressive symptoms and maintain smoking behavior. Yet, few studies have examined how depressive symptoms, even at low levels, influence CVC reactivity among individuals who smoke. Investigating these relationships may provide novel insights into how depressive symptoms exacerbate existing regulatory vulnerabilities among smokers. This study investigated how depression symptoms affect CVC reactivity as a function of changing situational demands among a community sample of 60 daily adult cigarette smokers. Participants completed a mildly demanding cognitive task while physiological data was recorded. Growth curve modeling was used to examine the main and interactive effects of self-reported depressive symptoms on CVC reactivity over the course of the task. We hypothesized that greater depressive symptoms would be associated with less CVC reactivity, characterized by smaller initial reductions in CVC values and a flatter slope over time. Participants were daily smokers with mild to moderate levels of depression. Final model results, where time was specified as linear and the slope was fixed, showed no significant main or interactive effects of time and depression symptoms on CVC reactivity. Findings suggest that at low to moderate levels, depressive symptom severity is not related to patterns of CVC reactivity among adults who smoke. This is the first study to examine this relationship in this population. Future investigations that examine patterns of CVC reactivity among smokers and non-smokers with more severe depression are needed.

Two Operational Modes of Cardio-Respiratory Coupling Revealed by Pulse-Respiration Quotient

Due to the fact that respiratory breath-to-breath and cardiac intervals between two successive R peaks (BBI and RRI, respectively) are not temporally concurrent, in a previous paper, we proposed a method to calculate both the integer and non-integer parts of the pulse respiration quotient (PRQ = BBI/RRI = PRQ_int + b1 + b2), b1 and b2 being parts of the border RRIs for each BBI. In this work, we study the correlations between BBI and PRQ, as well as those between BBI and mean RRI within each BBI (mRRI), on a group of twenty subjects in four conditions: in supine and standing positions, in combination with spontaneous and slow breathing. Results show that the BBI vs. PRQ correlations are positive; whereas the breathing regime had little or no effect on the linear regression slopes, body posture did. Two types of scatter plots were obtained with the BBI vs. mRRI correlations: one showed points aggregated around the concurrent PRQ_int lines, while the other showed randomly distributed points. Five out of six of the proposed aggregation measures confirmed the existence of these two cardio-respiratory coupling regimes. We also used b1 to study the positions of R pulses relative to the respiration onsets and showed that they were more synchronous with sympathetic activation. Overall, this method should be used in different pathological states.

Reducing decision-making deficits in patients with brain injury: effect of slow-paced breathing

Impairments in decision-making have been reported in brain-damaged (stroke/traumatic brain injury) patients with a wide range of lesion sites. Here, we propose that the performances of patients in complex sequential decision-making (DM) tasks can be explained by their negative affectivity, leading to deliberative processing associated with poor DM performances. We assumed that a slow-paced breathing (SPB) training, by reducing negative affectivity would improve performances in a complex DM task. For 24 days, 34 brain-damaged patients (16 males and 18 females; 12 had a hemorrhagic stroke, 17 with an ischemic stroke and 5 with a TBI), practiced either daily SPB or sham trainings for five min, three times a day. Before and after training, we assessed their vagal tone (electrocardiogram-ECG), affectivity (Positive and Negative Affect Schedule-PANAS) and certainty level (Dimensional Ratings Questionnaire-DRQ) and their performance on the Iowa Gambling Task. All participants showed initial weak performance, which improved only for patients in the SPB training condition. These results suggest that DM disorders in brain-damaged patients can be the consequence of their poor information processing strategy rather than an impairment in their DM abilities. Second, we showed that SPB could be efficient to normalize DM processes in brain injury patients.

Pre-partum HRV as a predictor of postpartum depression: The potential use of a smartphone application for physiological recordings

BACKGROUND

This study aimed to investigate the role of a time-domain Heart Rate Variability index (the root mean square of successive difference between NN intervals, rMSSD) as a predictor of the onset of postpartum depression. HRV has been related to an increased risk of depression in the general population. However, its role in pregnant women is not clear, and the potential use of smartphone applications to evaluate HRV in this population has not been investigated.

METHODS

In study 1, simultaneous electrocardiogram and smartphone photoplethysmography were collected. The rMSSD was determined from each recording to evaluate the accuracy of a smartphone application in the measurement of HRV. In study 2, 135 pregnant women provided rMSSD values measured through a smartphone application in the prepartum (second or third trimester) and filled in the Edinburgh Postnatal Depression Scale in the postpartum (one month after the childbirth).

RESULTS

Study 1 showed the excellent accuracy of the smartphone application in the measurement of rMSSD. Study 2 indicated that lower prepartum rMSSD predicted higher depressive symptoms in the postpartum (β = -0.217, p = 0.010) after controlling for prepartum depressive symptoms and other potential covariates.

LIMITATIONS

Artefacts (e.g., hand movements) might have corrupted the physiological signal registered.

CONCLUSION

This study showed that a reduced vagal tone, indexed by lower rMSSD, during pregnancy was a predictor of depressive symptoms one month after childbirth. The prepartum period may offer an important timeframe to implement preventive intervention on vagal modulation in order to prevent depressive symptoms in the postpartum.

Emotional and autonomic response to visual erotic stimulation in patients with functional hypothalamic amenorrhea

Introduction

Functional hypothalamic amenorrhea (FHA) is a clinical condition associated with high levels of physiological and psychological stress ranging from weight loss to maladaptive behavior and coping skills. A reliable measure of the psychophysiological response to stress and the ability to cope with stimuli is heart rate variability (HRV). Through the sympathetic (SNS) and parasympathetic nervous system (PNS), the autonomic nervous system (ANS) promotes various changes in HRV that reflect the individual's psychophysiological response to stress. FHA patients are characterized by high levels of PNS activation during psychological load, suggesting that parasympathetic hyperactivation could be a pathology marker.

Methods

In the present study, we examine changes in HRV during observation of erotic, neutral, and disgusting images in 10 patients with FHA [(mean ± S.D.) age: 26.8 ± 5.9] and in 9 controls (age: 25.4 ± 6.4; BMI: 22.47 ± 2.97) to assess the differential activation of PNS and SNS between FHA patients and controls matched for age and without other clinical conditions.

Results

Our results showed that FHA patients had significantly higher HRV activation while observing high emotional value images and not during the observation of neutral images confirming a parasympathetic hyperactivation.

Discussion

HRV and cognitive and psychological testing, could provide new insights into understanding such a clinically understudied condition and provide further tools for clinical diagnosis and treatment.

Atypical Response to Affective Touch in Children with Autism: Multi-Parametric Exploration of the Autonomic System

This study aimed at evaluating the autonomic response to pleasant affective touch in children with Autism Spectrum Disorders (ASD) and age-matched typically developing (TD) peers, thanks to multiple autonomic nervous system (ANS) parameters and by contrasting CT (C-tactile fibers) high- vs. low-density territory stimulations. We measured pupil diameter, skin conductance, and heart rate during gentle stroking of two skin territories (CT high- and low-density, respectively, forearm and palm of the hand) in thirty 6-12-year-old TD children and twenty ASD children. TD children showed an increase in pupil diameter and skin conductance associated with a heart rate deceleration in response to tactile stimulations at the two locations. Only the pupil was influenced by the stimulated location, with a later dilation peak following CT low-density territory stimulation. Globally, ASD children exhibited reduced autonomic responses, as well as different ANS baseline values compared to TD children. These atypical ANS responses to pleasant touch in ASD children were not specific to CT-fiber stimulation. Overall, these results point towards both basal autonomic dysregulation and lower tactile autonomic evoked responses in ASD, possibly reflecting lower arousal and related to social disengagement.

"Katerina gets mad": Infants' physiological and behavioral responses to co-viewing educational, self-regulatory media

A growing body of research has focused on the physiological impact of media on older children and adolescents. Less research has been focused on the potential physiological impact of media on infants and younger children, especially media designed to be age appropriate and educational in content. In this study, we examined respiratory sinus arrhythmia (RSA) in infants (N = 269, M_age  = 17.13 months) while they co-viewed an educational video clip that modeled emotion regulation and contrasted their physiological response to an unoccupied baseline and a frustration paradigm (arm-restraint). Given parent reports showing the calming effect of educational media viewing in young children, we anticipated that a similar pattern of calming would be observed physiologically in infants. Results showed that relative to baseline, most infants demonstrated an increase in RSA while co-viewing, suggesting greater parasympathetic (regulatory) activation consistent with behavioral calming. However, infants who demonstrated vagal withdrawal during co-viewing (decrease in RSA) were more likely to have parents who used a tablet to help infants go to sleep at night. Vagal withdrawal was also associated with increased levels of negative affect observed during the co-viewing task. Findings are discussed in relation to the contextual effect of co-viewing age-appropriate, educational media on children's physiological responses.

Autonomic measures identify stress, pain, and instability associated with retinopathy of prematurity ophthalmologic examinations

BACKGROUND

Retinopathy of prematurity (ROP) ophthalmologic examinations cause stress and pain. Infants' stress and pain can be measured non-invasively using skin conductance (SC) and high frequency heart rate variability (HF-HRV), reflecting sympathetic-mediated sweating and parasympathetic activity, respectively.

OBJECTIVES

To test the utility of SC to detect sympathetic activation during ROP examination, and the contribution of HF-HRV to predict stability post-examination.

METHODS

In this prospective, single center study, we measured SC continuously pre-, during, and post-examination, and HRV at 24 h pre-ROP examination. Clinical data included stability [apneas, bradycardias, and desaturations (A/B/Ds)], and interventions post-examination.

RESULTS

SC increased 56% above baseline during ROP examination (p = 0.001) and remained elevated post-examination (p = 0.02). Post-hoc analysis showed higher illness acuity, represented by need for respiratory support, was associated with lower HF-HRV at 24 h pre-ROP examination (p = 0.001). Linear regression indicated lower HF-HRV at 24 h pre-examination contributed to the need for higher intervention (i.e., stimulation to breathe, oxygen support) particularly among infants with higher illness acuity [F(1, 15) = 5.05, p = 0.04; β = -1.33, p = 0.04].

CONCLUSION

ROP examination induced a 2-fold increase in sympathetic activation which remained above baseline in recovery. Also, we propose that the low parasympathetic tone associated with autonomic imbalance contributes to instability and need for higher intervention to assure stabilization with A/B/D events. Our findings provide insight into the underestimation of adverse events associated with ROP examination and identification of infants who may be more vulnerable to potential sequelae following ROP examinations.

Measuring heart rate variability using a heart rate monitor in horses (Equus caballus) during groundwork

Measuring physiological parameters of stress in horses during groundwork, for example when involved in equine-assisted interventions, is important to gain insight into the stress levels of the horses. Heart rate and heart rate variability can be used as physiological indicators of stress in horses. Heart rate monitors could be easily incorporated into practice, as they are not expensive and easy to use. However, it is questionable whether heart rate monitors present accurate heart rate variability results in exercising horses, similar to electrocardiograms. The aim of this study was to determine the accuracy of heart rate monitors for the assessment of heart rate variability in horses during groundwork exercise. Simultaneous telemetric electrocardiograms (Televet) and heart rate monitor (Polar H10 transmitter and M430 receiver, Hylofit electrodes) recordings were performed on 28 horses (15 mares and 13 geldings). Results indicate that the heart rate monitor accurately determined heart rate and time-domain heart rate variability parameters when compared to electrocardiograms during both baseline and groundwork conditions. As expected, heart rate significantly increased and the heart rate variability significantly decreased during groundwork compared to baseline conditions. This indicates that the heart rate monitor can be used to accurately determine heart rate variability during groundwork.

Autonomic tone in children and adults: Pupillary, electrodermal and cardiac activity at rest

Considering the suspected involvement of the autonomic nervous system (ANS) in several neurodevelopmental disorders, a description of its tonus in typical populations and of its maturation between childhood and adulthood is necessary. We aimed to arrive at a better understanding of the maturation of the sympathetic (SNS) and parasympathetic (PNS) tonus by comparing children and adults at rest, via recordings of multiple ANS indices. We recorded simultaneously pupil diameter, electrodermal activity (EDA) and cardiac activity (RR interval and HRV: heart rate variability) in 29 children (6-12 years old) and 30 adults (20-42 years old) during a 5-min rest period. Children exhibited lower RR intervals, higher LF peak frequencies, and lower LF/HF (low frequency/high frequency) ratios compared to adults. Children also produced more spontaneous EDA peaks, reflected in a larger EDA AUC (area under the curve), in comparison with adults. Finally, children displayed a larger median pupil diameter and a higher pupillary hippus frequency than adults. Our results converged towards higher SNS and PNS tones in children compared to adults. Childhood would thus be characterized by a high autonomic tone, possibly reflecting a physiological state compatible with developmental acquisitions.