reviews our current experience with a recently developed device (VU-AMD [ambulatory monitoring device]) for the ambulatory measurement of the electrocardiogram (EKG) and changes in thoracic impedance (ICG) / with this device simultaneous assessment can be made of HR [heart rate], HR variability (HRV), the pre-ejection period (PEP), left ventricular ejection time (LVET), respiration rate (RR) and respiratory sinus arrhythmia (RSA) / PEP and RSA are currently our best noninvasive tools to assess sympathetic and parasympathetic influences on the heart reliability of the VU-AMD was tested in cross-instrument comparison against the “golden standard” of our laboratory devices / to determine feasibility [and validity] of field measurements, a set of 40 Ss has been measured on a 24-hr basis / as a final step we explored the possibilities of this new technique for research into behaviorally induced cardiovascular pathology / in 2 studies, 24-hr profiles of PEP and RSA were obtained with the VU-AMD in S groups with different risk profiles for cardiovascular disease [presence vs absence of insulin resistance syndrome and exercisers vs non-exercisers] (PsycInfo Database Record (c) 2020 APA, all rights reserved)

OBJECTIVE: To test the hypotheses that dysregulation of the autonomic nervous system (ANS) is associated with the presence of chronic widespread pain (CWP), and that dysregulation of the ANS is associated with higher pain intensity in CWP.
METHODS: Cross-sectional data were obtained from 1,574 subjects (healthy controls as well as persons with depressive and anxiety disorders) participating in The Netherlands Study of Depression and Anxiety. The Chronic Pain Grade was used to assess pain intensity and pain-related disability. Heart rate (HR), SD of the normal-to-normal interval (SDNN), the preejection period (PEP), and respiratory sinus arrhythmia (RSA) were used to assess the ANS. Logistic regression analyses and linear regression analyses were conducted with adjustment for potential confounders.
RESULTS: No differences in HR, PEP, SDNN, or RSA values were found between CWP subjects and controls after adjustment for confounders. However, lower SDNN and lower RSA were associated with higher pain intensity in subjects with CWP.
CONCLUSION: Lower parasympathetic activity, as assessed with SDNN and RSA, is associated with higher pain intensity in subjects with CWP. This large and well-controlled study does not provide evidence for an association between dysregulation of the ANS and the presence of CWP.

Objective
To examine whether ceiling effects at long inter beat intervals (IBIs)cause an underestimation of cardiac vagal control in regular exercisers by time and frequency-domain measures of respiratory sinus arrhythmia (RSA).
Methods
24-hour ECG and respiration recordings were performed in 26 regularly exercising subjects, actively engaged in aerobic training for the past year, and enrolled in supervised training in the six weeks pre-study, and in 26 age- and sex-matched non-exercisers. Sleep and waking levels of cardiac vagal control were estimated by RSA obtained through the peak–valley method, by the standard deviation of the IBIs, the root mean square of successive IBIs, and the high frequency IBI spectral power.
Results
In 11 of the exercisers the IBI–RSA relationship was characterized by a quadratic relationship. This reflected a ceiling effect at very long IBI values attained by regular exercisers, particularly during the nighttime recording. Irrespective of this ceiling effect, RSA as well as other heart rate variability (HRV) measures was still significantly larger in the exercisers with a quadratic IBI–RSA relationship than in non-exercisers or exercisers with a linear IBI–RSA relationship.
Conclusions
We conclude that a subgroup of regular exercisers is characterized by a low heart rate paired to high levels of cardiac vagal control. In these exercisers, vagal control is underestimated from HRV measures in ambulatory recordings. Inspection of the IBI–RSA relationship should be routinely added when HRV measures are used to index cardiac vagal control.

This study estimated the heritability of 24-h heart rate variability (HRV) measures, while considering ceiling effects on HRV at low heart rates during the night. HRV was indexed by the standard deviation of all valid interbeat intervals (SDNN), the root mean square of differences between valid, successive interbeat intervals (RMSSD), and peak-valley respiratory sinus arrhythmia (pvRSA). Sleep and waking levels of cardiac vagal control were assessed in 1,003 twins and 285 of their non-twin siblings. Comparable heritability estimates were found for SDNN (46%–53%), RMSSD (49%–54%), and pvRSA (48%–57%) during the day and night. A nighttime ceiling effect was revealed in 10.7% of participants by a quadratic relationship between mean pvRSA and the interbeat interval. Excluding these participants did not change the heritability estimates. The genetic factors influencing ambulatory pvRSA, RMSSD, and SDNN largely overlap. These results suggest that gene-finding studies may pool the different cardiac vagal indices and that exclusion of participants with low heart rates is not required.

Salivary alpha-amylase (sAA) is used as a sympathetic (SNS) stress marker, though its release is likely co-determined by SNS and parasympathetic (PNS) activation. The SNS and PNS show asynchronous changes during acute stressors, and sAA responses may thus vary with sample timing. Thirty-four participants underwent an eight-minute memory task (MT) and cold pressor task (CPT). Cardiovascular SNS (pre-ejection period, blood pressure) and PNS (heart rate variability) activity were monitored continuously. Unstimulated saliva was collected repeatedly during and after each laboratory stressor, and sAA concentration (U/ml) and secretion (U/minute) determined. Both stressors increased anxiety. The MT caused an immediate and continued cardiac SNS activation, but sAA concentration increased at task cessation only (+54%); i.e., when there was SNS–PNS co-activation. During the MT sAA secretion even decreased (−35%) in conjunction with flow rate and vagal tone. The CPT robustly increased blood pressure but not sAA. In summary, sAA fluctuations did not parallel changes in cardiac SNS activity or anxiety. sAA responses seem contingent on sample timing and flow rate, likely involving both SNS and PNS influences. Verification using other stressors and contexts seems warranted.

The Sing-a-Song Stress Test (SSST) was recently developed as an alternative to the Trier Social Stress Test (TSST) to investigate autonomic nervous system responses to social-evaluative stress. In the SSST, participants are suddenly cued to sing a song in the presence of confederates. However, the SSST is still quite long (~15 min) and the requirement for confederates makes it labor-intensive. The current study tested whether a shorter (~6.5 min), single-experimenter, version of the SSST can still reliably elicit subjective and physiological stress reactivity. Our sample consisted of 87 healthy young adult participants (age range: 18–35 years). During the short SSST and a speeded reaction time task, in which aversive loud tones were to be avoided (TA), we measured heart period (HP), sympathetic nervous system (SNS) activity using pre-ejection-period (PEP), skin conductance level (SCL), and non-specific skin conductance responses (ns.SCR), and parasympathetic nervous system (PNS) activity using respiratory-sinus-arrhythmia (RSA) and the root-mean-square of successive differences (RMSSD). The short SSST induced significant decreases in positive affect and increases in negative affect. MANOVAs on the clusters of SNS and PNS variables showed that the short SSST elicited significant HP (−118.46 ms), PEP (−7.76 ms), SCL (+4.85 μS), ns.SCR (+8.42 peaks/min) and RMSSD (−14.67) reactivity. Affective, SNS, and PNS reactivity to the new SSST social-evaluative stress task were of comparable magnitude to that evoked by the TA mental stressor. We conclude that the short SSST is a valid and cost-effective task for large scaled studies to induce social-evaluative stress to a sufficient degree to evoke measurable changes in PNS and SNS activity and affective state.

In recent years, increasing interest has been devoted to the physiological basis of self and other-oriented compassion. Heart rate variability (HRV) represents a promising candidate for such a role, given its association with soothing emotions and context appropriate prefrontal inhibitory control over threat-defensive responses. The aim of this study was to meta-analyze available studies on the association between compassion and HRV. Random-effect models were used. The analysis performed on sixteen studies that met inclusion criteria, yielded a significant association with a medium effect size (g = .54 95% CI [.24, .84], p < .0001). Results were not influenced by publication bias. After an extreme outlier’s exclusion, the size of the association was still larger in studies that used time or frequency-domain indices of vagally-mediated HRV compared to those that used peak to trough estimates of respiratory sinus arrhythmia. Results are limited by the small number of studies included in the meta-analysis (n = 16) and are discussed in terms of indications for future research, given that existing data are highly heterogeneous and of poor methodological rigor.

Reduced responsiveness to emotions is hypothesized to contribute to the development of conduct disorder (CD) in children and adolescents. Accordingly, blunted psychophysiological responses to emotions have been observed in boys with CD, but this has never been tested in girls. Therefore, this study compared psychophysiological responses to sadness in girls and boys with and without CD, and different clinical phenotypes of CD: with versus without limited prosocial emotions (LPE), and with versus without comorbid internalizing disorders (INT). Nine-hundred and 27 girls (427 CD, 500 controls) and 519 boys (266 CD, 253 controls) aged 9–18 years participated. Psychophysiological responses were measured while participants watched two validated sad film clips, specifically: heart rate (HR), respiratory sinus arrhythmia (RSA; indexing parasympathetic activity), preejection period (PEP; indexing sympathetic activity). Girls and boys with CD showed larger HR responses to sadness than controls. This effect was rendered nonsignificant, however, after controlling for covariates. We observed aberrant RSA responses to sadness in CD compared with controls. Similarly, we found a significant positive association between RSA responsivity and antisocial behavior when assessed dimensionally. The effects were very small, though. Results were similar for boys and girls. We found no evidence for emotional underresponsiveness in CD in the largest psychophysiological study to date in this field. More research is needed to explore whether this is specific to sadness or generalizes to other emotions. Furthermore, we recommend that studies on emotion processing in CD assess different physiological measures to help disentangle CD-related effects on sympathetic and parasympathetic activity. (PsycInfo Database Record (c) 2022 APA, all rights reserved)

Many adolescents in residential care have experienced traumatic events and suffer from posttraumatic stress. Prolonged activation of neurobiological stress systems as the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis can result in long-lasting maladaptive alternations. This study investigated the effectiveness of Muse, a game-based meditation intervention, on the sympathetic nervous system (SNS), parasympathetic nervous system (PNS), and cortisol basal activity and reactivity to acute stress among adolescents with posttraumatic symptoms in residential care. The intervention consisted of two gameplay sessions a week, for 6 consecutive weeks. Seventy-seven adolescents with clinical levels of posttraumatic symptoms (10–18 years old) received either Muse as an addition to treatment as usual (n = 40) or treatment as usual alone (n = 37). We expected reduced basal activity for the SNS and cortisol and increased basal activity for the PNS. As for the response to acute stress, we expected decreased PNS and increased HPA axis reactivity. The Muse group exhibited lower basal activity for the SNS and increased HPA reactivity to acute stress. There were no differences between conditions on SNS and HPA axis activity during rest and on SNS and PNS reactivity to acute stress. Game-based meditation therapy is a promising intervention for the treatment of adolescents with posttraumatic symptoms in residential care. Implications for clinical relevance and trauma-focused treatment purposes are discussed.

Alterations in neurobiological stress systems such as the autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis contribute to the development and maintenance of psychological and behavioral problems after traumatic experiences. Investigating neurobiological parameters and how these relate to each other may provide insight into the complex mechanisms at play. Whereas the preponderance of studies focuses on either the ANS or the HPA axis separately, the current study is the first to evaluate relations between posttraumatic stress and both basal activity during rest and stress reactivity of the ANS as well as the HPA axis in a sample of traumatized adolescents and healthy controls. The traumatized sample (n = 77), based on clinical levels of posttraumatic stress, was a convenience sample that was recruited within residential institutions, was compared to a healthy control sample (n = 48) recruited within the general community. For the ANS, we expected increased SNS and decreased PNS activity during rest and increased SNS and decreased PNS reactivity to social stress among traumatized adolescents compared to healthy controls. Regarding the HPA axis, we expected increased basal cortisol levels and decreased cortisol reactivity to stress in the traumatized sample. Compared to healthy controls, traumatized adolescents exhibited significantly higher sympathetic and lower parasympathetic activation during rest and increased sympathetic reactivity to acute stress (ANS parameters). Outcomes on the HPA axis (i.e. cortisol) indicated that traumatized adolescents showed increased cortisol levels during rest and blunted cortisol reactivity to acute stress. Implications for clinical relevance and trauma-focused treatment purposes are discussed.