Attenuated reactivity of salivary alpha-amylase has been proposed as a specific sympathetic marker of disruptive behavior in juveniles and may have additional value to studying other autonomic parameters and hypothalamic–pituitary–adrenal axis activity. Investigating the interrelationships between neurobiological parameters in relation to juvenile disruptive behavior may enhance insight into the complex mechanisms at play. We investigated salivary alpha-amylase, cortisol, heart rate (HR), and heart rate variability (HRV) in response to a standardized public speaking task, and examined interactions between these parameters in relation to disruptive behavior. Participants were 48 delinquent male adolescents (mean age 18.4years, SD 0.9), with and without a disruptive behavior disorder (resp. DP+, DP−) and 16 matched normal controls (NC). A structured psychiatric interview as well as the Youth Self Report and Child Behavior Checklist were administered to assess disruptive behavior. Alpha-amylase and cortisol reactivity, but not HR or HRV, showed significant inverse associations with dimensional measures of disruptive behavior. Moreover, both cortisol and alpha-amylase reactivity were significantly lower in the DP+ group as compared to the NC group. The mentioned relationships remained present when nicotine use was entered as a covariate. Combining alpha-amylase and cortisol in one model explained a larger part of the variance of disruptive behavior than either single parameter. There were no interactions between alpha-amylase and cortisol or HRV in relation to disruptive behavior. Attenuated alpha-amylase responsivity to stress is a correlate of disruptive behavior in late-adolescent males. Although nicotine use explains a considerable part of the variance of disruptive behavior, both alpha-amylase and cortisol are related to disruptive behavior, over and above the effect of nicotine use. Combining alpha-amylase and cortisol improved insight into neurobiological mechanisms involved with disruptive behavior; concurrent low reactivity of both parameters was related to higher levels of disruptive behavior.

Objective Stressors have been related to medically insufficiently explained or functional somatic symptoms (FSS). However, the underlying mechanism of this association is largely unclear. In the current study, we examined whether FSS are associated with different perceived stress and cardiac autonomic nervous system (ANS) levels during a standardized stressful situation, and whether these associations are symptom-specific. Methods We examined 715 adolescents (16.1 years, 51.3% girls) from the Dutch cohort study Tracking Adolescents’ Individual Lives Sample during the Groningen Social Stress Test (GSST). FSS were assessed by the Youth Self-Report, and clustered into a cluster of overtiredness, dizziness and musculoskeletal pain and a cluster of headache and gastrointestinal symptoms. Perceived stress levels (i.e. unpleasantness and arousal) were assessed by the Self-Assessment Manikin, and cardiac ANS activity by assessing heart rate variability (HRV-HF) and pre-ejection period (PEP). Perceived stress and cardiac ANS levels before, during, and after the GSST were studied as well as cardiac ANS reactivity. Linear regression analyses were used to examine the associations. Results Perceived arousal levels during (beta = 0.09, p = 0.04) and after (beta = 0.07, p = 0.047) the GSST, and perceived unpleasantness levels before (beta = 0.07, p = 0.048) and during (beta = 0.12, p = 0.001) the GSST were related to FSS during the past couple of months. The association between perceived stress and FSS was stronger for the FSS cluster of overtiredness, dizziness and musculoskeletal pain than for the cluster of headache and gastrointestinal symptoms. Neither ANS activity levels before, during, and after the GSST, nor maximal HF-HRV and PEP reactivity were related to FSS. Conclusions This study suggests that perceived stress levels during social stress are related to FSS, whereas cardiac ANS activity and reactivity are not related to FSS.

Large individual differences exist in aerobic fitness in childhood and adolescence, but the relative contribution of genetic factors to this variation remains to be established. In a sample of adolescent twins and siblings (n = 479), heart rate (HR) and maximal oxygen uptake (V̇o2max) were recorded during the climax of a graded maximal exercise test. In addition, V̇o2max was predicted in two graded submaximal exercise tests on the cycle ergometer and the treadmill, using extrapolation of the HR/V̇o2 curve to the predicted HRmax. Heritability estimates for measured V̇o2max were 60% in ml/min and 55% for V̇o2max in ml·min−1·kg−1. Phenotypic correlations between measured V̇o2max and predicted V̇o2max from either submaximal treadmill or cycle ergometer tests were modest (0.57 < r < 0.70), in part because of the poor agreement between predicted and actual HRmax. The majority of this correlation was explained by genetic factors; therefore, the submaximal exercise tests still led to very comparable estimates of heritability of V̇o2max. To arrive at a robust estimate for the heritability of V̇o2max in children to young adults, a sample size weighted meta-analysis was performed on all extant twin and sibling studies in this age range. Eight studies, including the current study, were meta-analyzed and resulted in a weighted heritability estimate of 59% (ml/min) and 72% (ml·min−1·kg−1) for V̇o2max. Taken together, the twin-sibling study and meta-analyses showed that from childhood to early adulthood genetic factors determine more than half of the individual differences in V̇o2max.

Aim Many youth in residential care suffer from post-traumatic symptoms that have adverse effects on a range of psychological, behavioural and physiological outcomes. Although current evidence-based treatment options are effective, they have their limitations. Meditation interventions are an alternative to traditional trauma-focused treatment. This pilot study aimed to evaluate three game-based meditation interventions in a sample of traumatized youth in residential care. Methods Fifteen participants were randomly divided over three conditions (Muse, DayDream and Wild Divine) that all consisted of twelve 15-minute game-play sessions. Physiological measurements (heart rate variability) were conducted at baseline, post-treatment and during each intervention session. Post-traumatic symptoms, stress, depression, anxiety and aggression were assessed at baseline, post-treatment and 1-month follow-up. Results Physiological stress regulation was improved during the meditation sessions of all three interventions. User evaluations were in particular high for Muse with a rating of 8.42 out of 10 for game evaluation. Overall, outcomes on psychopathology demonstrated the most robust effect on stress. Muse performed best, with all participants showing reliable improvements (reliable change indexes [RCIs]) in post-traumatic symptoms, stress and anxiety. Participants who played Daydream or Wild Divine showed inconsistent progression: some participants improved, whereas others remained stable or even deteriorated based on their RCIs. Conclusions Preliminary findings show promising outcomes on physiology, psychopathology and user evaluations. All indicate the potential of this innovative form of stress regulation intervention, and the potential of Muse in particular, although findings should be considered preliminary due to our small sample size. Further studies are warranted to assess intervention effectiveness effects of Muse or other game-based meditation interventions for traumatized youth.

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.

Wired ambulatory monitoring of the electrocardiogram (ECG) is an established method used by researchers and clinicians. Recently, a new generation of wireless, compact, and relatively inexpensive heart rate monitors have become available. However, before these monitors can be used in scientific research and clinical practice, their feasibility, validity, and reproducibility characteristics have to be investigated. Therefore, we tested how two wireless heart rate monitors (i.e., the Ithlete photoplethysmography (PPG) finger sensor and the Cortrium C3 ECG monitor perform against an established wired reference method (the VU-AMS ambulatory ECG monitor). Monitors were tested on cross-instrument and test-retest reproducibility in a controlled laboratory setting, while feasibility was evaluated in protocolled ambulatory settings at home. We found that the Cortrium and the Ithlete monitors showed acceptable agreement with the VU-AMS reference in laboratory setting. In ambulatory settings, assessments were feasible with both wireless devices although more valid data were obtained with the Cortrium than with the Ithlete. We conclude that both monitors have their merits under controlled laboratory settings where motion artefacts are minimized and stationarity of the ECG signal is optimized by design. These findings are promising for long-term ambulatory ECG measurements, although more research is needed to test whether the wireless devices’ feasibility, validity, and reproducibility characteristics also hold in unprotocolled daily life settings with natural variations in posture and activities.

Dysregulated autonomic nervous system (ANS) activity has been associated with adolescent risk-taking and internalizing behavior, but previous results in community samples have been mixed. We investigated whether ANS activity was associated with higher risk-taking and internalizing behavior in young adolescents (age 11/12; n = 875), and whether adolescents’ gender, parents’ parenting style or a combination of both moderated these associations. Adolescents and their parents were recruited as part of the population-based, longitudinal Amsterdam Born Children and their Development (ABCD) study. Risk-taking behavior was assessed with the Balloon Analogue Risk Task and the personality characteristics sensation seeking and impulsivity, measured with the Substance Use Risk Profile Scale (SURPS). Internalizing behavior was assessed via the SURPS subscales anxiety sensitivity and hopelessness. Authoritative (AUTH-SW) and authoritarian (AUTH-S) parenting styles were measured with the Parenting Styles and Dimensions Questionnaire. Resting ANS activity was assessed via heart rate and respiratory sinus arrhythmia (RSA). Hierarchical, multivariable regression analyses showed higher RSA, but not heart rate, being associated with higher risk-taking behavior and sensation seeking. The associations between ANS activity and risk-taking variables were not significantly moderated by gender, parenting, or interactions between gender and parenting. Our findings suggest that RSA activity may be a relevant factor in mild to moderate risk-taking behavior in adolescents from the general population, regardless of their gender or the type of parenting they experience.

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.