Supportive hand-holding attenuates pupillary responses to stress in adult couples

Assessing response to stressful emotions: a controlled crossover study using pupillometry

Background

Fear and horror induce autonomic protective responses, acting as "survival intelligence." Pupillometry is an innovative method that captures real-time autonomic nervous system reactions to stress.

Objective

To evaluate the feasibility of pupillometry to assess the acute response to a passive real-life stressor-viewing a truthful war scene.

Methods

Thirteen medical students (10 women) with an average age of 20.4 years were enrolled in a nonrandomized controlled crossover trial. Selected clips from two different audiovisual stimuli (M1: Saving Private Ryan as a fear and horror inducer and M2: Life Is Beautiful as a control) were watched for 15 minutes, separated by a washout period of 48-72 hours. The differences in pupillometry parameters between the exposure movie and the assessment time (T0 and T1 for M1 and T0 and T1 for M2) were evaluated using a Wilcoxon test. The Wilcoxon test was also used to assess the difference between M1 and M2 within each assessment time point (T0 and T1).

Results

A significant difference in response to acute fear and horror-induced stress was observed in pupillometry parameters {baseline [6.90 (5.95; 7.40) vs. 6.60 (5.55; 7.10), P = 0.030] and final pupil diameter [4.50 (3.90; 5.20) vs. 4.10 (3.50; 4.60), P = 0.012]} between M1 and M2 in T1, suggesting the acute increase in sympathetic parameters. Although not significant, there was also a difference in pupillometry parameters (final pupil diameter [P = 0.060], average constriction velocity [P = 0.059]) after watching M1 compared with T0.

Conclusion

Our proof-of-concept study suggests that pupillometry may be used to evaluate changes in the activity of the autonomic nervous system induced by an acute passive stress stimulus.

Pupillometry and autonomic nervous system responses to cognitive load and false feedback: an unsupervised machine learning approach

Objectives

Pupil dilation is controlled both by sympathetic and parasympathetic nervous system branches. We hypothesized that the dynamic of pupil size changes under cognitive load with additional false feedback can predict individual behavior along with heart rate variability (HRV) patterns and eye movements reflecting specific adaptability to cognitive stress. To test this, we employed an unsupervised machine learning approach to recognize groups of individuals distinguished by pupil dilation dynamics and then compared their autonomic nervous system (ANS) responses along with time, performance, and self-esteem indicators in cognitive tasks.

Methods

Cohort of 70 participants were exposed to tasks with increasing cognitive load and deception, with measurements of pupillary dynamics, HRV, eye movements, and cognitive performance and behavioral data. Utilizing machine learning k-means clustering algorithm, pupillometry data were segmented to distinct responses to increasing cognitive load and deceit. Further analysis compared clusters, focusing on how physiological (HRV, eye movements) and cognitive metrics (time, mistakes, self-esteem) varied across two clusters of different pupillary response patterns, investigating the relationship between pupil dynamics and autonomic reactions.

Results

Cluster analysis of pupillometry data identified two distinct groups with statistically significant varying physiological and behavioral responses. Cluster 0 showed elevated HRV, alongside larger initial pupil sizes. Cluster 1 participants presented lower HRV but demonstrated increased and pronounced oculomotor activity. Behavioral differences included reporting more errors and lower self-esteem in Cluster 0, and faster response times with more precise reactions to deception demonstrated by Cluster 1. Lifestyle variations such as smoking habits and differences in Epworth Sleepiness Scale scores were significant between the clusters.

Conclusion

The differentiation in pupillary dynamics and related metrics between the clusters underlines the complex interplay between autonomic regulation, cognitive load, and behavioral responses to cognitive load and deceptive feedback. These findings underscore the potential of pupillometry combined with machine learning in identifying individual differences in stress resilience and cognitive performance. Our research on pupillary dynamics and ANS patterns can lead to the development of remote diagnostic tools for real-time cognitive stress monitoring and performance optimization, applicable in clinical, educational, and occupational settings.

From Social Stress and Isolation to Autonomic Nervous System Dysregulation in Suicidal Behavior

PURPOSE OF REVIEW

In this narrative review we wanted to describe the relationship of autonomic nervous system activity with social environment and suicidal spectrum behaviors.

RECENT FINDINGS

Patients with suicidal ideation/suicide attempt have higher sympathetic nervous system (SNS) and lower parasympathetic nervous system (PNS) activity in resting conditions and during acute stress tasks compared with patients without suicidal ideation/suicide attempt. Death by suicide and violent suicide attempt also are related to SNS hyperactivation. Similarly, a SNS/PNS imbalance has been observed in people with childhood trauma, stressful life events or feelings of loneliness and isolation. Social support seems to increase PNS control and resilience. Due to the importance of the social context and stressful life events in suicidal behavior, SNS/PNS imbalance could act as a mediator in this relationship and be a source of relevant biomarkers. Childhood trauma and stressful life events may impair the autonomic nervous system response in suicidal patients. Loneliness, isolation and social support may act as moderators in acute stress situations.

Effect of recurrent task-induced acute stress on task performance, vagally mediated heart rate variability, and task-evoked pupil response

Advances in wearable sensor technologies can be leveraged to investigate behavioral and physiological responses in task-induced stress environments. Reliable and valid multidimensional assessments are required to detect stress given its multidimensional nature. This study investigated the effect of recurrent task-induced acute stress on task performance, vagally mediated heart variability measures (vmHRV) and task-evoked pupillary response (TEPR). Task performance, vmHRV measures, and TEPR were collected from 32 study participants while they performed a computer-based task in a recurrent task-induced acute stress environment. Mixed-effects modeling was used to assess the sensitivity of each outcome variable to experimental conditions. Repeated measures correlation tests were used to examine associations between outcome variables. Task performance degraded under stress. vmHRV measures were lower in the stress conditions relative to the no stress conditions. TEPR was found to be higher in the stress conditions compared to the no stress conditions. Task performance was negatively associated with the vmHRV measures, and degraded task performance was linked to increased TEPR in the stress conditions. There were positive associations between vmHRV measures. TEPR was negatively associated with vmHRV measures. Although task-induced stress degrades task performance, recurrent exposure to that stress could alter this effect via habituation. Further, our findings suggest that vmHRV measures and TEPR are sensitive enough to quantify psychophysiological responses to recurrent task-induced stress.

COVID-19 lockdown: Impact on college students' lives

Objective: In light of COVID-19, leaders issued stay-at-home orders, including closure of higher-education schools. Most students left campus, likely impacting their employment and social network. Leaders are making decisions about opening universities and modality of instruction. Understanding students' psychological, physiological, academic, and financial responses to the shut-down and reopening of campuses can help leaders make informed decisions. Participants: 654 students from a large western university enrolled during the pandemic shutdown. Methods: Students were invited via email to complete an online survey. Results: Students reported stress, depression, loneliness, lack of motivation, difficulty focusing on schoolwork, restless sleep, appetite changes, job loss concerns, and difficulties coping. Most wanted to return to campus and felt social/physical distancing was effective but were mixed in terms of testing or masks. Conclusions: Moving to remote learning created physical and psychological stress. Students want to return to campus but do not want to take risk-reducing measures.

Spousal emotional support and relationship quality buffers pupillary response to horror movies

Being satisfied in marriage provides protective stress buffering benefits to various health complications but the causal mechanisms and speed at which this is accomplished is less well understood. Much of the research on health and marriage has conceptualized marital quality in a unidimensional way, with high levels of either positivity or negativity. This conceptualization may not fully capture the nuanced benefits of marital relationships. Pupillometry is an innovative method which captures the effects of marital stress buffering on the body’s autonomic nervous system in real time; pupil dilation occurs within 200ms to stress exposure. Additionally, this method records hundreds of readings per second, providing precision and sensitivity. This preregistered experiment aimed to conceptually replicate previous pupillometry stress buffering results and extend the previous findings by including a generalizable, real-life stressor—viewing a horror movie—and multidimensional relationship quality effects. Eighty-three couples (166 participants) were quasi-grouped, based on a self-reported multidimensional relationship quality scale, to either supportive or ambivalent marital relationship conditions. They were then randomly assigned to either a spousal support (i.e., handholding) or non-support (spousal absence) condition and watched clips from both horror and nature movies while pupil dilation was measured. Tonic pupillary response results revealed that the horror video clips elicited a stress response and there were significant differences between the support and non-support conditions, as well as marital relationship quality conditions. These results frame the precision, speed, and sensitivity of pupillometry as a potentially fruitful method to investigate the causal mechanisms linking stress buffering and supportive marital relationships.

Getting in touch: A neural model of comforting touch

Comforting touch involves contact distress-alleviating behaviors of an observer towards the suffering of a target. A growing number of studies have investigated the effects of touch on pain attenuation, focusing on the (toucher), the target (comforted) or both. Here we synthesize findings of brain mechanisms underlying comforting touch in the target and toucher to propose an integrative brain model for understanding how touch attenuates distress. Building on evidence from the pain and distress literatures, our model applies interchangeably to pain and distress regulation. We describe comforting touch as a feedback-loop that begins with distress experienced by the target, triggering an empathic response in the toucher which in turn reduces distress in the target. This cycle is mediated by interactions between the neural circuits associated with touch perception, shared distress, emotion regulation and reward as well as brain-to-brain coupling in the observation-execution system. We conclude that formulating a model of comforting touch offers a mechanistic framework for understanding the effects of touch as well as other social interactions involving social support.

Effects of Hand Holding on Anxiety and Pain During Prostate Biopsies: A Pilot Randomized Controlled Trial

BACKGROUND

Effective pain management is limited for patients during prostate biopsy (PBx). Touch support, such as hand holding, has stress-buffering benefits and effective analgesic effects. We conducted a prospective, single-center randomized clinical trial to assess whether hand holding can reduce patient anxiety, pain, and dissatisfaction during PBx.

METHODS

Between April 2020 and October 2020, 120 male patients were randomized into three groups: a hand holding with relatives (HR) group, a hand holding with strangers (HS) group and a control group. A visual analog scale (VAS) was used for self-assessments of pain and satisfaction. Anxiety levels were quantified according to the State-Trait Anxiety Inventory (STAI). Hemodynamic changes were also measured.

RESULTS

The degree of pain and anxiety in the hand-holding groups was significantly better than that in the control group (P<0.001), and the patients were more willing to undergo repeat PBx (P=0.017). The anxiety levels in the HR group were significantly lower than those in the HS group (P=0.019). During PBx, the changes in systolic blood pressure and heart rate in the hand-holding groups were more stable than those in the control group (P<0.01), and the fluctuations in heart rate in the HR group were smaller than those in the HS group (P<0.01).

CONCLUSION

Hand holding, especially with relatives, can promote incremental reductions in anxiety, pain and dissatisfaction in patients during PBx. Hence, we recommend hand holding with relatives as an effective adjunct during PBx.

Calming Effects of Touch in Human, Animal, and Robotic Interaction-Scientific State-of-the-Art and Technical Advances

Small everyday gestures such as a tap on the shoulder can affect the way humans feel and act. Touch can have a calming effect and alter the way stress is handled, thereby promoting mental and physical health. Due to current technical advances and the growing role of intelligent robots in households and healthcare, recent research also addressed the potential of robotic touch for stress reduction. In addition, touch by non-human agents such as animals or inanimate objects may have a calming effect. This conceptual article will review a selection of the most relevant studies reporting the physiological, hormonal, neural, and subjective effects of touch on stress, arousal, and negative affect. Robotic systems capable of non-social touch will be assessed together with control strategies and sensor technologies. Parallels and differences of human-to-human touch and human-to-non-human touch will be discussed. We propose that, under appropriate conditions, touch can act as (social) signal for safety, even when the interaction partner is an animal or a machine. We will also outline potential directions for future research and clinical relevance. Thereby, this review can provide a foundation for further investigations into the beneficial contribution of touch by different agents to regulate negative affect and arousal in humans.

Best practices in eye tracking research

This guide describes best practices in using eye tracking technology for research in a variety of disciplines. A basic outline of the anatomy and physiology of the eyes and of eye movements is provided, along with a description of the sorts of research questions eye tracking can address. We then explain how eye tracking technology works and what sorts of data it generates, and provide guidance on how to select and use an eye tracker as well as selecting appropriate eye tracking measures. Challenges to the validity of eye tracking studies are described, along with recommendations for overcoming these challenges. We then outline correct reporting standards for eye tracking studies.