Heart rate variability (HRV) in adolescent females with anxiety disorders and major depressive disorder

Reliability of an "At-Home" Method for Monitoring Resting and Reactive Autonomic Nervous System Activity in Children: A Pilot Study

BACKGROUND

Heart rate variability (HRV), an index of the functional status of the autonomic nervous system (ANS), provides an opportunity for early detection of ANS dysfunction. Lower resting, vagally related HRV parameters are associated with increased risk of physical and mental illness. External factors influencing the ANS, such as the testing environment, may impact the interpretation of HRV. This study's main aim was to determine the reliability of HRV resting and reactivity tests performed at home with children aged 4-9 years.

METHODS

Fourteen healthy children (female n = 8) aged 6.8 ± 1.5 years participated. Two HRV tests were performed at home via online supervision 7 days apart using a Polar H10 heart rate monitor. The absolute and relative reliability of the pre-exercise resting (5 min) and sub-maximal exercise step test recovery (4 × 30 s segments) HRV time and frequency domains were calculated.

RESULTS

The Pearson correlation coefficients for day 1 versus day 7 for the vagal activity HRV domains (RMSSD log) at rest and in the first 30 s and 30-60 s of recovery indicated good-to-excellent relative reliability (r > 0.8, p < 0.01). Absolute reliability was moderate for the resting RMSSD log, with a coefficient of variation (CV) of 5.2% (90% CI: 3.9, 7.8%), high for the first 30 s of standing recovery, with a CV of 10.7% (90% CI: 8.2, 15.7%), and moderate for 30-60 s of recovery, with a CV of 8.7% (90% CI: 6.6, 12.9%).

CONCLUSIONS

The findings of this pilot study indicate that the resting and exercise recovery HRV measures of vagal activity can be measured reliably at home in children. This represents a novel "at-home" protocol for monitoring ANS health and development in children.

The relationship between depression severity and heart rate variability in children and adolescents: A meta-analysis

OBJECTIVE

Depression in children and adolescents has gradually attracted social attention. Heart rate variability (HRV) has been found to be influenced by depression severity, but results have not been uniformed in children and adolescents. This study investigated the relationship between depression severity and heart rate variability in children and adolescents, aiming to provide additional evidence for an objective, effective, and convenient depression screening tool in this population.

METHODS

Literature searching was conducted in China National Knowledge Infrastructure (CNKI), Wanfang Data, Web of Science, PubMed, ScienceDirect, and EBSCO. Relevant studies investigating the relationship between depression severity and HRV in children and adolescents were selected for meta-analysis.

RESULTS

31 articles were included in this meta-analysis, involving 4534 participants. Depression severity in children and adolescents was significantly negatively correlated with high frequency (HF) and root mean square of successive differences (RMSSD) in HRV (HF: r = -0.10, 95% CI: -0.17 to -0.04, p = 0.001; RMSSD: r = -0.18, 95% CI: -0.30 to -0.05, p = 0.01). The relationship between HF and depression severity was moderated by age, higher among those aged >12 than among those aged <12 (r = -0.17, -0.02, Q = 7.32, p = 0.007).

CONCLUSION

Heart rate variability is associated with depression severity in children and adolescents.

Evaluation of the impact of overlapping upper gastrointestinal symptoms on the clinical characteristics of patients with functional constipation, along with risk factor analysis

OBJECTIVES

Functional constipation (FC), a common functional gastrointestinal disorder, is usually overlapping with upper gastrointestinal symptoms (UGS). We aimed to explore the clinical characteristics of patients with FC overlapping UGS along with the related risk factors.

METHODS

The differences in the severity of constipation symptoms, psychological state, quality of life (QoL), anorectal motility and perception function, autonomic function, and the effect of biofeedback therapy (BFT) among patients with FC in different groups were analyzed, along with the risk factors of overlapping UGS.

RESULTS

Compared with patients with FC alone, those with FC overlapping UGS had higher scores in the Patient Assessment of Constipation Symptoms and Self-Rating Anxiety Scale and lower scores in the Short Form-36 health survey (P < 0.05). Patients with FC overlapping UGS also had lower rectal propulsion, more negative autonomic nervous function, and worse BFT efficacy (P < 0.05). Overlapping UGS, especially overlapping functional dyspepsia, considerably affected the severity of FC. Logistic regression model showed that age, body mass index (BMI), anxiety, exercise, and sleep quality were independent factors influencing overlapping UGS in patients with FC.

CONCLUSIONS

Overlapping UGS reduces the physical and mental health and the QoL of patients with FC. It also increases the difficulty in the treatment of FC. Patient's age, BMI, anxiety, physical exercise, and sleep quality might be predictors for FC overlapping UGS.

Vagally-mediated heart rate variability and depression in children and adolescents - A meta-analytic update

BACKGROUND

Depression is one of the most common mental disorders and a leading cause of disability worldwide. In adults, depression is characterized by decreased vagal activity (vagally-mediated heart rate variability; vmHRV), while vmHRV is inversely correlated with depressive symptoms. In children/adolescents, a 2016 synthesis (4 studies, 259 individuals) found similarly decreased vmHRV in clinical depression, but no significant association between depressive symptoms and vmHRV (6 studies, 2625 individuals). Given the small number of studies previously considered for synthesis and the rapidly growing evidence base in this area, a meta-analytic update was warranted.

METHOD

A previous review was updated by a systematic literature search to identify studies that (a) compared vmHRV in clinically depressed children/adolescents with non-depressed controls and (b) reported associations between vmHRV and depression severity.

RESULTS

The search update identified 5 additional studies for group comparison (k = 9 studies in total, n = 608 individuals in total) and 15 additional studies for correlational meta-analysis (k = 21 studies in total, n = 4224 individuals in total). Evidence was found for lower resting-state vmHRV in clinically depressed children/adolescents compared to healthy controls (SMD = -0.593, 95 % CI [-1.1760; -0.0101], I2 = 90.92 %) but not for a significant association between vmHRV and depressive symptoms (r = -0.053, 95 % CI [-0.118; 0.012], I2 = 65.77 %). Meta-regression revealed a significant association between depressive symptoms and vmHRV as a function of sex.

LIMITATIONS

The samples considered are highly heterogeneous. Data on the longitudinal association between vmHRV and depression are currently lacking.

CONCLUSION

The present findings support the use of vmHRV as a biomarker for clinical depression in children/adolescents.

Heart rate variability in children and adolescents with major depressive disorder: A systematic review and meta-analysis

Although reduced heart rate variability (HRV) has been observed in adults with major depressive disorder (MDD), the correlation between HRV and MDD in children and adolescents remains uncertain and requires to be systematically reviewed. Our meta-analysis included ten articles comprising 410 MDD patients and 409 healthy controls. Adolescents with MDD showed significant reductions in most HRV measures, such as HF-HRV, RMSSD, and PNN50, and depressive symptom severity was statistically associated with RMSSD, HF-HRV, and LF/HF ratio. A large heterogeneity across studies was detected. Sensitivity analysis revealed that removal of a specific study would significantly decline the heterogeneity for measures of HF-HRV, LF-HRV, and SDNN, and meta-regression analysis found that sample size and year of publication substantially moderated the differences between depressed samples and controls in RMSSD. Compared with adults, depression-induced autonomic dysfunction was more detectable in children and adolescents with substantial effects. Moreover, excluded studies which reported both HRV and MDD or depression symptoms were summarized based on objectives. Findings indicate that it is promising for HRV to be an appropriate and objective candidate biomarker for clinically depressed children and adolescents.

Dataset of Psychological Scales and Physiological Signals Collected for Anxiety Assessment Using a Portable Device

Portable and wearable devices are becoming increasingly common in our daily lives. In this study, we examined the impact of anxiety-inducing videos on biosignals, particularly electrocardiogram (ECG) and respiration (RES) signals, that were collected using a portable device. Two psychological scales (Beck Anxiety Inventory and Hamilton Anxiety Rating Scale) were used to assess overall anxiety before induction. The data were collected at Simon Fraser University from participants aged 18–56, all of whom were healthy at the time. The ECG and RES signals were collected simultaneously while participants continuously watched video clips that stimulated anxiety-inducing (negative experience) and non-anxiety-inducing events (positive experience). The ECG and RES signals were recorded simultaneously at 500 Hz. The final dataset consisted of psychological scores and physiological signals from 19 participants (14 males and 5 females) who watched eight video clips. This dataset can be used to explore the instantaneous relationship between ECG and RES waveforms and anxiety-inducing video clips to uncover and evaluate the latent characteristic information contained in these biosignals.

The Effects of Lifestyle Intervention Using the Modified Beliefs, Attitude, Subjective Norms, Enabling Factors Model in Hypertension Management: Quasi-Experimental Study

BACKGROUND

Hypertension is a serious health issue and a significant risk factor for cardiovascular disease and stroke. Although various health education models have been used to improve lifestyle in patients with hypertension, the findings have been inconsistent.

OBJECTIVE

This study aims to assess the effects of a lifestyle intervention program using a modified Beliefs, Attitude, Subjective Norms, Enabling Factors (BASNEF) model among nonadherent participants with hypertension in managing elevated blood pressure (BP) levels.

METHODS

This study reports a quantitative quasi-experimental research work, particularly using a repeated-measures design of the within-subjects approach on the 50 nonadherent patients who received a diagnosis of essential hypertension in Cebu, Philippines. The research participants received 5 sessions of training based on a modified BASNEF model. An adherence instrument was used as an evaluation platform. The first phase gathers participants' relevant profiles and background, and the final phase gathers participants' systolic BP, diastolic BP, heart rate, and adherence scores.

RESULTS

The results indicate that the phase 1 mean systolic readings (146.50, SD 19.59) differ significantly from the phase 4 mean systolic readings (134.92, SD 15.24). They also suggest that the lifestyle intervention based on session III or phase IV behavioral intention in the BASNEF model microgroup sessions positively affects BP readings among the research participants.

CONCLUSIONS

This study has established that the BASNEF model approach can be a good BP management technique.

Correspondence of parasympathetic-mediated heart rate variability derived from electrocardiogram and photoplethysmography signals in ethnically diverse adolescents

The reliable and valid assessment of heart rate variability (HRV) is important to understanding autonomic functioning in youth. However, use of electrocardiogram (ECG) signals to derive estimates of parasympathetic-mediated HRV may present logistical barriers in applied settings. Thus, this study investigated the concordance between high-frequency HRV [HF-HRV] and root mean square of successive differences [RMSSD] derived from ECG and photoplethysmography (PPG) signals during a video baseline, resting baseline, and mental arithmetic among an ethnically diverse sample of ninety-six youths (M_age = 13.84; 51% male; 62.5% ethnic minority). Results showed moderate to almost perfect agreement between PPG- and ECG- derived HF-HRV and RMSSD for video and resting baselines (Lin's correlations ranged from 0.93 to 0.99) and limits of agreement (LoA) ranging from -0.48 to 0.58 (HF-HRV) and - 11.37 to 9.32 (RMSSD). Conversely, we found poor to moderate agreement for the mental arithmetic task (Lin's correlations ranged from 0.88 to 0.91) and LoA ranging from -0.68 + 0.94 (HF-HRV) and - 17.58 + 20.69 (RMSSD), though we did find ethnic minority youth had higher and moderate Lin's correlations (0.93 to 0.94). Overall, there was a bias towards higher HF-HRV and RMSSD values with PPG. Findings suggest that PPG-derived HF-HRV and RMSSD may be viable alternatives for ECG in baseline conditions, but tasks requiring movement or eliciting mild stress responses may result in less than perfect values and missing data patterns. It is imperative that future studies replicate these findings in other ethnically diverse youth samples and expand to younger children and applied settings.

Gender Matters: Nonlinear Relationships Between Heart Rate Variability and Depression and Positive Affect

Vagally mediated heart rate variability (vmHRV), a measure of the parasympathetic nervous system's control over the heart, is often negatively related to maladaptive emotional outcomes. Recent work suggests that quadratic relationships involving these factors may be present; however, research has not investigated gender differences in these nonlinear functions. To address this gap, the current study tested for quadratic relationships between resting vmHRV and depression and positive affect while investigating gender differences in these relationships. Significant quadratic effects were found between resting vmHRV and reports of both depression symptoms and positive affect in women but not men. Specifically, the lowest levels of depression and the highest levels of positive affect were found at moderate vmHRV in women. These results suggest that examinations of vmHRV's nonlinear associations require the consideration of gender. Our findings are interpreted based on proposed differential neuropsychological mechanisms of vmHRV in men versus women.

Respiratory Sinus Arrhythmia Mediates the Relation Between "Specific Math Anxiety" and Arithmetic Speed

There is a growing consensus that math anxiety highly correlates with trait anxiety and that the emotional component elicited by math anxiety affects math performance. Yet few studies have examined the impact of “specific math anxiety” (high math anxiety and low other kinds of anxiety) on math performance and the underlying physiological and affective mechanism. The present study examines the mediation effect of heart rate variability—an affective measurement indexed by respiratory sinus arrhythmia (RSA)—in the relationship between specific math anxiety and arithmetic speed. A total of 386 junior high school students completed a self-reported questionnaire to measure their anxiety level. Among this sample, 29 individuals with specific math anxiety (high math anxiety and low reading and trait anxiety), 29 with specific reading anxiety (high reading anxiety and low math and trait anxiety), 24 with specific trait anxiety (high trait anxiety and low math and reading anxiety), and 22 controls (low math, trait and reading anxiety) were selected to participate in an arithmetic task and a reading task while RSA was recorded when they performed the tasks. Results revealed that individuals with specific math anxiety showed lower RSA and longer reaction time than the other three groups in the arithmetic task. Regression and mediation analyses further revealed that RSA mediated the relation between specific math anxiety and arithmetic speed. The present study provides the first account of evidence for the affective hypothesis of specific math anxiety and suggests that affective responses may be an important mechanism underlying the detrimental effect of specific math anxiety on math performance.

Clinical Effectiveness of Training for Awareness Resilience and Action Online Compared to Standard Treatment for Adolescents and Young Adults With Depression: Study Protocol and Analysis Plan for a Pragmatic, Multi-Center Randomized Controlled Superiority Trial

Depression in adolescents and young adults is an increasing global health concern. Available treatments are not sufficiently effective and relapse rates remain high. The novel group-treatment program "Training for Awareness, Resilience and Action" (TARA) targets specific mechanisms based on neuroscientific findings in adolescent depression. TARA is framed within the National Institute of Mental Health's Research Domain Criteria and has documented feasibility and preliminary efficacy in the treatment of adolescent depression. Since neurodevelopment continues well into the mid-twenties, age-adapted treatments are warranted also for young adults. Patients 15-22 years old, with either major depressive disorder (MDD) or persistent depressive disorder (PDD) according to the DSM-IV/5 or a rating >40 on the clinician rating scale Children's Depression Rating Scale-Revised (CDRS-R), will be recruited from specialized Child and Adolescent Psychiatry and local Youth-Clinics and randomized to either TARA or standard treatment, including but not limited to antidepressant medication and/or psychotherapy. Outcome measures will be obtained before randomization (T₀), after 3 months of treatment (T₁) and at 6-months- (T₂) and 24-months- (T₃) follow-up. Additionally, dose-response measures will be obtained weekly in the TARA-arm and measures for mediation-analysis will be obtained halfway through treatment (T_0.5). Primary outcome measure is Reynolds Adolescent Depression Scale (RADS-2) score at T₁. Secondary outcome measures include RADS-2 score at T₂, Multidimensional Anxiety Scale for Children at T₁ and T₂, and CDRS-R at T₁. Additional outcome measures include self-report measures of depression-associated symptoms, systemic bio-indicators of depression from blood and hair, heartrate variability, brain magnetic resonance imaging, as well as three-axial accelerometry for sleep-objectivization. Qualitative data will be gathered to reach a more comprehensive understanding of the factors affecting adolescents and young adults with depression and the extent to which the different treatments address these factors. In summary, this article describes the design, methods and statistical analysis plan for pragmatically evaluating the clinical effectiveness of TARA. This will be the first RCT to examine the effects of TARA compared to standard treatment for adolescents and young adults with MDD or PDD. We argue that this study will extend the current knowledgebase regarding the treatment of depression. NCT Registration: identifier [NCT04747340].

Troubled Hearts: Association Between Heart Rate Variability and Depressive Symptoms in Healthy Children

Heart rate variability (HRV) captures the change in timing of consecutive heart beats and is reduced in individuals with depression and anxiety. The present study investigated whether typically-developing children without clinically recognized signs of depression or anxiety showed a relationship between HRV and depressive or anxiety symptoms. Children aged 9-14 years (N = 104) provided three minutes of cardiac signal during eyes closed rest and eyes open rest. The association between high frequency HRV, low frequency HRV, root mean square of the successive differences (RMSSD), and pNN20 versus depressive symptoms (NIH Toolbox and Child Behavior Checklist) was investigated. Results partially confirm our hypothesis, with pNN20 positively correlated with the self-reported depression measure of loneliness while controlling for age, sex, social status, and physical activity. The association was stronger in male participants. However, there is no consensus in the literature about which HRV measures are associated with depressive symptoms in healthy children. Additional studies are needed which reliably account for variables that influence HRV to establish whether certain HRV measures can be used as an early marker for depression risk in children.

Depressive symptoms among stress-exposed youth: Relations with tonic and phasic indices of autonomic functioning

Theoretical models of adolescent depression postulate that one possible individual vulnerability factor for the development of depressive symptoms is autonomic dysregulation. However, there is limited and mixed support for these models among ethnically diverse and higher risk stress-exposed youth. Therefore, this study investigated the relations between both tonic and phasic indices of parasympathetic autonomic functioning (i.e., resting high-frequency heart rate variability [HF-HRV] and root mean square of successive differences [RMSSD]; HF-HRV and RMSSD reactivity to a mental arithmetic stressor) and depressive symptoms among 80 severely stress-exposed youth (51% female; 11-17 years of age) from diverse backgrounds (61.3% ethnic minority; caregiver-reported median family income = $20,000-$49,999 per year). Results demonstrated that lower resting HF-HRV and RMSSD, but not HF-HRV and RMSSD reactivity, was associated with greater youth depressive symptoms. Our findings suggest that lower resting parasympathetic autonomic functioning may be a potential vulnerability factor of depressive symptoms among stress-exposed youth, instead of specific emotional responses to stressors. These findings will need to be replicated in larger samples of stress-exposed youth and youth at higher risk for or exhibiting clinical levels of depressive symptoms to better elucidate relations with autonomic functioning and depressive symptoms among adolescents.

Heart Rate Variability, Risk-Taking Behavior and Resilience in Firefighters During a Simulated Extinguish-Fire Task

Firefighters face a high-risk potential, thus their psychological ability to cope with critical or traumatic events is a crucial characteristic. This study examines correlations between cardiac autonomic modulation, risk-taking behavior, and resilience in professional firefighters. Twenty male professional firefighters underwent a 20 min beat-to-beat heart rate (HR) monitoring at baseline in the morning upon awakening, then before, during and after a realistic deployment in a container, systematically set on fire. Risk-taking behavior, resilience, and subjective stress were assessed by specific validated tools after deployment: the Risk-taking Scale (R-1), the Resilience Scale (RS-13), and the multi-dimensional NASA-Task Load Index. The cardiac autonomic modulation at rest and in response to stress was assessed by classic indexes of heart rate variability (HRV) as RMSSD and LF/HF ratio. Results showed that: (i) risk-taking behavior correlated with a withdrawal in vagal indices, shifted the baseline sympathovagal balance toward sympathetic predominance (LF/HF ratio r(8) = 0.522, p = 0.01), and increased mean HR both in baseline and during physical exercise (r(8) = 0.526, p = 0.01 and r(8) = 0.445, p = 0.05, respectively); (ii) resilience was associated with higher vagal indices (RMSSD r(18) = 0.288, p = 0.04), and with a baseline sympathovagal balance shifted toward parasympathetic predominance (LF/HF ratio r(18) = −0.289, p = 0.04). Associations of risk-taking behavior and resilience with cardiac autonomic modulation could be demonstrated, showing that HRV may be a valuable monitoring tool in this specific population; however further studies are warranted for validation.

Measuring Heart Rate Variability Using Commercially Available Devices in Healthy Children: A Validity and Reliability Study

Heart rate variability (HRV) is an accepted method for determining autonomic nervous system activity and cardiovascular risk in various populations. This study assessed the validity and reliability of a commercially available finger photoplethysmography (PPG) system for measuring pediatric HRV in a real-world setting. Sixteen healthy children (4.06 ± 0.58 years) were recruited. The PPG system was compared to the Polar H10 heart rate (HR) sensor validated against ECG (gold standard) for HRV measurement. Seated short-term resting R-R intervals were recorded simultaneously using both systems. Recordings were performed on 3 days at the participants’ school. Paired t-tests, effect sizes and Bland–Altman analyses determined the validity of the PPG system. The relative and absolute reliability of both systems were calculated. No HRV parameters were valid for the PPG system. Polar H10 yielded moderate (0.50–0.75) to good (0.75–0.90) relative reliability with R-R intervals and the standard deviation of instantaneous and continuous R-R variability ratio showing the best results (ICCs = 0.84). Polar H10 displayed better absolute reliability with the root mean square of successive differences, R-R intervals and HR showing the lowest values (TEM% < 12%). The use of the Polar H10 and not the PPG system is encouraged for HRV measurement of young children in an educational real-world setting.

Comparison of Baroreflex Sensitivity and Cardiac Autonomic Function Between Adolescent Athlete and Non-athlete Boys - A Cross-Sectional Study

Introduction: It is well known that regular physical activity improves cardiovascular health, and higher baroreflex sensitivity and heart rate variability are associated with cardiovascular health. Adolescence is the age when an individual's behavior is easily modified; early intervention at this stage in terms of physical conditioning or training prevents future cardiovascular risk. Hence, we conceived the present study to assess and compare the baroreflex sensitivity and autonomic function between adolescent athletes and non-athletes. Methods: We recruited school going athletes (n = 30) and non-athlete boys (n = 30) in the 10-19 age group after obtaining their assent and consent from their parents. We assessed height, weight, heart rate, blood pressure, baroreflex sensitivity, and cardiac autonomic function. Comparison between groups was made using the unpaired t-test for height, weight, body mass index, heart rate, blood pressure, and baroreflex sensitivity and using Mann-Whitney U test for cardiac autonomic function parameters. Results: There was a trend for higher baroreflex sensitivity in athletes. Heart rate variability (total power and SDNN) was higher in athletes. The parasympathetic tone was higher in terms of higher RMSSD, and higher HF power. Parasympathetic reactivity was higher in athletes in terms of higher 30:15 ratio and EI ratio. Conclusion: Athletic level physical conditioning has a positive influence on baroreflex function and autonomic function that may prove beneficial to the adolescents' cardiovascular health.

The association between perseverative cognition and resting heart rate variability: A focus on state ruminative thoughts

OBJECTIVE

Two studies were conducted to shed light on the associations between trait and state rumination and worry and a time-domain metric of heart rate variability, the root mean square of successive differences (RMSSD) of cardiac interbeat-interval (IBI).

METHOD

Study 1 involved 130 healthy adults (118 females; mean age = 23.4 ± 3.59 years), while 72 healthy participants (58 females; mean age = 22.2 ± 1.79 years) were involved in Study 2. RMSSD was calculated from a 5-min baseline recording and state ruminative thoughts were assessed during measurement. Trait perseverative cognitions were measured using self-reported questionnaires.

RESULTS

In Study 1, we found that a higher level of state but not trait ruminative thoughts showed weak negative association with lnRMSSD. In Study 2, we replicated the results of Study 1 and we found that trait reflection moderated the relationship between state rumination and lnRMSSD.

CONCLUSION

State rumination may reflect actual cardiovascular activity better than trait preservative cognitions, although trait reflection could be a protective factor.

Complex cardiac vagal regulation to mental and physiological stress in adolescent major depression

BACKGROUND

Cardiovagal control is known to be reduced in major depressive disorder (MDD), however, the neurocardiac reflex control to distinct types of stressors is still unclear. We aimed to study parasympathetically mediated cardiac reflex functioning in response to mental and physiological stressors using heart rate variability (HRV) linear and nonlinear analysis in adolescent MDD.

METHODS

We examined 60 adolescents (40 girls) with MDD (age 14.9 ± 0.3 years) and 60 age and gender-matched controls. ECG was continuously recorded during stress protocol: baseline, Go/NoGo test, recovery, supine position, and orthostasis. Evaluated HRV linear and nonlinear indices: RR interval, pNN50, rMSSD, HF-HRV, Poincaré plot (SD1), symbolic dynamics 2UV%. Cardiovagal reactivity expressed as percentual change (%) was calculated in response to both stressors.

RESULTS

In each phase of stress protocol, the MDD group had significantly reduced HRV parameters compared to controls, except for symbolic dynamics index 2UV% in supine position. The reactivity of HRV indices was significantly greater in response to orthostasis in MDD compared to controls. No significant differences were found in response to Go/NoGo test.

LIMITATIONS

The smoking status and the menstrual cycle phase potentially affecting the HRV parameters were not monitored. Future research is needed to expand a sample size with respect to sex and to study neurocardiac response to other different stressors in MDD.

CONCLUSIONS

This study revealed reduced resting cardiovagal regulation and greater vagal withdrawal indicating abnormal neurocardiac reflex functioning to physiological stressor (orthostasis) in adolescent MDD patients. Nonlinear HRV analysis was sensitive to detect cardiac-linked regulatory differences in adolescent depression.

Mean Heart Rate and Parameters of Heart Rate Variability in Depressive Children and the Effects of Antidepressant Medication

Introduction: Researchers have repeatedly discovered an association between depression and autonomic cardiac dysregulation in adults. However, corresponding data concerning minors are still rare. Method: For this exploratory, cross-sectional study, we included N = 43 minors (age range 9-17 years). The subjects were depressive subjects with or without antidepressant medication (N = 23) or healthy control children (HC) (N = 20). We assessed several indices of cardiac functioning using long-term electrocardiogram data (mean heart rate, HR, and several parameters of heart rate variability, HRV). We hypothesized that increased HR and reduced HRV are associated with depressive disorders. Furthermore, we assessed the impact of age, sex, and antidepressant medication on HR and HRV. Results: When sex and age were controlled for, HR was significantly increased in depressive minors compared to HC. However, our preliminary data suggest that this might not be the case in medicated patients, and there were no differences between groups regarding HRV parameters. There was no significant correlation in the whole sample between severity of depression and both HR and HRV. In the subsample of patients with depression, antidepressant medication was associated with lower HR and higher indices of HRV. Conclusion: The data indicate an association between depression and altered autonomic cardiac regulation, which can already manifests in minors.

Effects of smoking status, history and intensity on heart rate variability in the general population: The CHRIS study

Background

Heart rate variability (HRV) reflects the autonomous nervous system modulation on heart rate and is associated with several pathologies, including cardiac mortality. While mechanistic studies show that smoking is associated with lower HRV, population-based studies present conflicting results.

Methods

We assessed the mutual effects of active smoking status, cumulative smoking history, and current smoking intensity, on HRV among 4751 adults from the Cooperative Health Research In South Tyrol (CHRIS) study. The HRV metrics standard deviation of normal-to-normal (NN) inter-beat intervals (SDNN), square root of the mean squared differences of consecutive NN intervals (RMSSD), total power (TP), low (LF) and high frequency (HF) power, and their ratio (LF/HF), were derived from 20-minute electrocardiograms. Smoking status, pack-years (PY), and tobacco grams/day from standardized questionnaires were the main exposures. We fitted linear mixed models to account for relatedness, non-linearity, and moderating effects, and including fractional polynomials.

Results

Past smokers had higher HRV levels than never smokers, independently of PY. The association of HRV with current smoking became apparent when accounting for the interaction between smoking status and PY. In current smokers, but not in past smokers, we observed HRV reductions between 2.0% (SDNN) and 4.9% (TP) every 5 PY increase. Furthermore, current smokers were characterized by dose-response reductions of 9.8% (SDNN), 8.9% (RMSSD), 20.1% (TP), 17.7% (LF), and 19.1% (HF), respectively, every 10 grams/day of smoked tobacco, independently of common cardiometabolic conditions and HRV-modifying drugs. The LF/HF ratio was not associated with smoking status, history, or intensity.

Conclusions

Smoking cessation was associated with higher HRV levels. In current smokers, heavier smoking intensity appears gradually detrimental on HRV, corroborating previous evidence. By affecting both the sympathetic and parasympathetic nervous system indexes, but not the LF/HF balance, smoking intensity seems to exert a systemic dysautonomic effect.

Gut permeability and depressive symptom severity in unmedicated adolescents

OBJECTIVE

This study examined gut permeability in unmedicated adolescents with and without major depressive disorder.

METHOD

Medically healthy, non-medicated, 12-17 year-old females in a major depressive episode (MDE) or healthy controls, without any psychiatric condition, were enrolled. They completed the Children's Depression Rating Scale-Revised (CDRS-R) and underwent a clinical interview. Preejection period (PEP) and respiratory sinus arrhythmia (RSA) data were collected to measure autonomic nervous system activity. Following an overnight fast, participants ingested lactulose and mannitol and collected urine for 4 hours while still fasting, to examine gut permeability. Plasma cytokines (interleukin 1β, interleukin 6, and tumor necrosis factor α) were measured. Correlational analyses were used to examine the associations between relevant variables.

RESULTS

41 female participants (age: 14.8 ± 1.6 years, n = 25 with MDE) were enrolled. PEP, but not RSA, was inversely associated with neurovegetative symptom severity on the CDRS-R (r = -0.31, p < 0.06). In the 30 participants with gut permeability data, the lactulose to mannitol ratio (LMR) was significantly positively associated with depression severity, particularly neurovegetative symptom severity (r = 0.37, p < 0.05). Notably, the association between neurovegetative symptom severity and PEP was substantially reduced after adjusting for LMR. Additionally, depression severity was significantly associated with circulating cytokines.

CONCLUSIONS

This is the first study to examine gut permeability in unmedicated adolescents, offering preliminary support for a mechanistic pathway linking sympathetic nervous system activation to increased gut permeability and activation of the innate immune system, likely contributing to the emergence of neurovegetative symptoms of depression.

Stress reactivity in healthy child offspring of parents with anxiety disorders

Several studies suggest that anxiety disorders (AD) involve dysregulation of the autonomic nervous system (ANS) and hypothalamic-pituitary (HPA) axis. However, it is unknown if alterations in these biological systems are premorbid markers of AD risk or a state-dependent feature of anxiety. This study examined ANS and HPA-axis response to a laboratory stressor in healthy child offspring of parents with (n = 55) and without (n = 98) a history of AD. High frequency heart rate variability (HF-HRV) was assessed during sitting and standing baseline conditions and during a speech task where participants remained standing. Salivary cortisol was measured at baseline and at 15, 30, 45 and 60 min post-speech. Subjective anxiety was assessed with a visual analogue scale. Children of parents with AD displayed reduced HRV and a blunted cortisol response to the speech task compared to children of non-anxious parents. No risk group effect was found for anxiety ratings. These preliminary data suggest that healthy children of anxious parents exhibit altered stress reactivity to an acute laboratory stressor. Further research is needed to confirm findings and identify mechanisms that may account for altered self-regulation processes to a stressor in children at familial risk for AD.

Heart rate variability changes in major depressive disorder during sleep: Fractal index correlates with BDI score during REM sleep

We investigated the relationship between autonomic nervous system activity during each sleep stage and the severity of depressive symptoms in patients with major depressive disorder (MDD) and healthy control subjects. Thirty patients with MDD and thirty healthy control subjects matched for sex, age, and body mass index completed standard overnight polysomnography. Depression severity was assessed using the Beck Depression Inventory (BDI). Time- and frequency-domain, and fractal HRV parameters were derived from 5-min electrocardiogram segments during light sleep, deep sleep, rapid eye movement (REM) sleep, and the pre- and post-sleep wake periods. Detrended fluctuation analysis (DFA) alpha-1 values during REM sleep were significantly higher in patients with MDD than in control subjects, and a significant correlation existed between DFA alpha-1 and BDI score in all subjects. DFA alpha-1 was the strongest predictor for the BDI score, along with REM density as a covariate. This study found that compared with controls, patients with MDD show reduced complexity in heart rate during REM sleep, which may represent lower cardiovascular adaptability in these patients, and could lead to cardiac disease. Moreover, DFA alpha-1 values measured during REM sleep may be useful as an indicator for the diagnosis and monitoring of depression.

Changes in heart rate variability in first-episode drug-naïve adolescents with major depressive disorder: A 12-week prospective study

BACKGROUND

Major depressive disorder (MDD) is a common mental disorder, the onset of which frequently occurs during adolescence. While differences in heart rate variability (HRV) between depressed and healthy participants have previously been observed, results have been inconsistent. This study thus investigated the features of HRV in adolescents with MDD.

METHODS

We recruited first-episode drug-naïve adolescents aged 13-18 years who had been diagnosed with MDD, and healthy age-matched controls. HRV was measured before and after a 12-week antidepressant treatment. We compared HRV measures between patient group and control group. We also tried to find correlation between HRV measures and depression rating scales.

RESULTS

Fifty-seven participants were included (patient group: n = 31; control group: n = 26). The patient group showed a lower normalized high frequency (HF norm), a higher normalized low frequency (LF norm), and a higher LF/HF ratio than did the control group. After treatment, LF was significantly decreased within the patient group compared to baseline. Hamilton Depression Rating Scales and Children's Depression Inventory scores were positively correlated with LF norm and LF/HF ratio, and negatively correlated with HF norm, when included all participants in analysis LIMITATIONS: Sample size of this study was small to assess influences of confounding factors on HRV. And follow up period was relatively short to see impact of pharmacotherapy.

CONCLUSION

An imbalance of the autonomic nervous system might be a meaningful feature of adolescent MDD, and HRV might represent a potential biological marker for pathophysiological changes in MDD.

Altered Salivary Alpha-Amylase Secretion in Patients with Ulcerative Colitis

Purpose

Patients with ulcerative colitis (UC) frequently present with psychological disturbances as well as dysfunctions of autonomic nervous system (ANS). Salivary alpha-amylase (sAA) secretion is predominantly controlled by sympathetic nervous activity, while salivary fluid secretion is by parasympathetic nervous activity. Thus, it is speculated that alterations of salivary secretion may be addressed in UC populations.

Methods

Thirty-five UC patients as well as 32 age- and sex-matched healthy controls were enrolled. Saliva samples before and after citric acid stimulation were collected from each participant, and salivary flow rate (SFR) was calculated accordingly. Western blotting and quantitative PCR were applied to measure the sAA level and sAA gene (AMY1) copy number, respectively. The psychological disorders, anxiety and depression, were evaluated by the scoring system of Hospital Anxiety and Depression Scale (HADS) for each participant.

Results

We observed robustly increased prevalence of anxiety (p < 0.001) as well as depression (p < 0.001) in UC patients relative to controls. Interestingly, we detected elevated basal (p = 0.015) and stimulated (p = 0.021) sAA levels in the UC populations compared to controls. However, no differences were found for basal (p = 0.643) or stimulated (p = 0.402) SFR between the two study groups. Besides, AMY1 gene copy number was comparable between UC patients and controls.

Conclusions

Our results reveal an overactivity of the sympathetic nervous system and a normal activity of the parasympathetic nervous system in the UC population.

Diminished heart rate complexity in adolescent girls: a sign of vulnerability to anxiety disorders?

BACKGROUND AND OBJECTIVES

Diminished heart rate variability has been found to be associated with high anxiety symptomatology. Since adolescence is the period of onset for many anxiety disorders, this study aimed to determine sex- and anxiety-related differences in heart rate variability and complexity in adolescents.

METHODS

We created four groups according to sex and anxiety symptomatology: high-anxiety girls (n = 24) and boys (n = 25), and low-anxiety girls (n = 22) and boys (n = 24) and recorded their cardiac function while they performed regular school activities. A series of two-way (sex and anxiety) MANOVAs were performed on time domain variability, frequency domain variability, and non-linear complexity.

RESULTS

We obtained no multivariate interaction effects between sex and anxiety, but highly anxious participants had lower heart rate variability than the low-anxiety group. Regarding sex, girls showed lower heart rate variability and complexity than boys.

CONCLUSIONS

The results suggest that adolescent girls have a less flexible cardiac system that could be a marker of the girls' vulnerability to developing anxiety disorders.

Heart rate variability in patients with major depression disorder during a clinical autonomic test

Major depression disorder (MDD) patients express dysfunction autonomic nervous system (ANS) and reduced heart rate variability (HRV). However, previous researches mainly focused on examining resting state without considering a series of stimulation tests of ANS between MDD patients and healthy people. For this purpose, 40 healthy people and 40 MDD patients participated and finished 10min clinical autonomic test-Ewing test. Parameters of HRV such as time domain, frequency domain, and nonlinear dynamical parameters were calculated. Most of HRV parameters during Ewing test of MDD patients are lower than healthy people, and inversely, the ratio of low frequency to high frequency is higher when standing up. In addition, heart rate of healthy people in deep breathing and Valsalva test states are higher than that in resting state, nonlinear dynamical parameter (RCMSE1) of healthy people in standing up state is higher than that in Valsalva test state. The experimental results suggest that parasympathetic nervous system of MDD patients is influenced by mental state and become dysfunction under long-term depression, it cannot exert normal physiological functions when it is activated. Sympathetic activity increases on MDD patients, and this enhancement is more obvious which expresses higher complexity of HRV time series.

Anxiety during pregnancy and autonomic nervous system activity: A longitudinal observational and cross-sectional study

OBJECTIVES

To assess the longitudinal change in autonomic nervous system (ANS) activity during pregnancy and the association between anxiety during pregnancy and ANS activity.

METHODS

Pregnant Japanese women with a singleton fetus and normal pregnancy were recruited (n=65). ANS activity and anxiety were measured using a self-rating questionnaire at approximately 20, 30, and 36weeks of gestation. Very low (VLF) and high (HF) frequency bands of heart rate variability spectrums were used. Anxiety was assessed using the Japanese version of the State-Trait Anxiety Inventory. A score of 45 or more on trait-anxiety and the other represent the trait-anxiety group and the non- trait-anxiety group, respectively. The state-anxiety group and the non-state-anxiety group were defined in the same manner.

RESULTS

Longitudinal observation of individual pregnant women indicated the significant increasing trend (p=0.002) of VLF power and the significant decreasing trend (p<0.001) of HF power during 20 to 36 gestation weeks. Compared with the non-trait-anxiety group, the trait-anxiety group had significantly lower VLF values at 20 gestational weeks (p=0.033) and had significantly lower HF values at 30 and 36 gestational weeks (p=0.015 and p=0.044, respectively). The increasing rate of VLF from 20 to 36 gestational weeks was higher among the trait-anxiety group. The same associations were observed between the state-anxiety and non-state-anxiety groups at 20 gestational weeks.

CONCLUSIONS

Anxiety during pregnancy decreased heart rate variability. Anxiety in second trimester pregnancy promoted a subsequent increase in sympathetic activity.

Respiratory sinus arrhythmia in the fourth decade of life depends on birth weight and the DRD4 gene: Implications for understanding the development of emotion regulation

INTRODUCTION

The long allele of the DRD4 gene can confer different behavioral and emotional phenotypes depending upon environmental exposure, although the physiological changes underlying these phenotypes are not fully known. We sought to extend this work by assessing the interaction of the DRD4 gene and exposure to perinatal adversity (indexed by extremely low birth weight [ELBW]) on resting respiratory sinus arrhythmia (RSA), a neurophysiological measure of emotion regulation, in adulthood.

METHODS

We examined the interaction between the DRD4 gene and perinatal adversity on RSA at age 30-35 in a longitudinal cohort of ELBW survivors (n = 49) and NBW controls (n = 63). Buccal DNA samples were genotyped for short and long carriers of the exon III DRD4 VNTR gene. Resting RSA was assessed by electrocardiogram.

RESULTS

We report an interaction between birth weight status and DRD4 gene (F = 9.42, p = 0.003) in predicting RSA, such that DRD4 long carriers had the highest and lowest resting RSA depending on whether they were born NBW or ELBW, respectively. DRD4 short carriers were less sensitive to birth weight. Additionally, reduced RSA was correlated with a history of major depressive disorder, suggesting it was a reliable index of emotion dysregulation.

DISCUSSION

These results suggest that the perinatal environment influences autonomic nervous system functioning in individuals with genotypes that confer additional sensitivity. Whether the long-term autonomic outcomes of this environmental sensitivity are beneficial or detrimental appears to depend on the quality of the early life environment, and may influence the development of emotion regulatory and psychiatric problems in adulthood.

The tell-tale heart: physiological reactivity during resolution of ambiguity in youth anxiety

In the past decade, cognitive biases and physiological arousal have each been proposed as mechanisms through which paediatric anxiety develops and is maintained over time. Preliminary studies have found associations between anxious interpretations of ambiguity, physiological arousal, and avoidance, supporting theories that link cognition, psychophysiology, and behaviour. However, little is known about the relationship between youths' resolutions of ambiguity and physiological arousal during acute stress. Such information may have important clinical implications for use of verbal self-regulation strategies and cognitive restructuring during treatments for paediatric anxiety. In this brief report, we present findings suggesting that anxious, but not typically developing, youth select avoidant goals via non-threatening resolution of ambiguity during a stressor, and that this resolution of ambiguity is accompanied by physiological reactivity (heart rate, heart rate variability, and respiratory sinus arrhythmia). We propose future empirical research on the interplay between interpretation bias, psychophysiology, and child anxiety, as well as clinical implications.

Anxiety Level and Cardiac Autonomic Modulations in Coronary Artery Disease and Cardiac Syndrome X Patients

BACKGROUND

Anxiety and cardiac autonomic modulations (CAM) were thoroughly investigated in coronary artery disease (CAD) and cardiac syndrome X (CSX) patients worldwide, but not among Sudanese with similar pathology.

AIMS

To compare levels of anxiety and CAM between Sudanese patients with CSX and CAD.

MATERIALS AND METHODS

Anxiety was evaluated in 51 CAD and 26 CSX patients using Taylor Manifest anxiety score (TMAS) questionnaire while heart rate variability derived indices were used to assess CAM, namely natural logarithm of low frequency (LnLF), high frequency (LnHF) and LF/HF ratio (LnLF/HF).

RESULTS

Low anxiety levels were achieved by 6 (23.1%) and 9 (17.6%) patients with CSX and CAD respectively. High anxiety level was achieved by only one (3.8%) patient, who was suffering from CSX. TMAS was significantly higher in CSX (31.27 (21.97)) compared to CAD (21.86 (12.97), P = 0.021). However, abnormally increased anxiety was not associated with higher risk of CSX. LnLF, LnHF and LnLF/HF were comparable in CAD and CSX patients.

CONCLUSION

CSX and CAD patients showed comparable CAM. Although anxiety levels were higher in CSX compared to CAD, TMAS ≥ 35 failed to show significant association with CSX.

Thinking anxious, feeling anxious, or both? Cognitive bias moderates the relationship between anxiety disorder status and sympathetic arousal in youth

Cognitive bias and physiological arousal are two putative markers that may underlie youth anxiety. However, data on relationships between cognitive bias and arousal are limited, and typically do not include behavioral measurement of these constructs in order to tap real-time processes. We aimed to examine the relationship between performance-based cognitive bias and sympathetic arousal during stress in clinically anxious and typically-developing youth. The sample included children and adolescents ages 9 to 17 (Mean age=13.18, SD=2.60) who either met diagnostic criteria for primary generalized anxiety, social phobia, or separation anxiety (N=24) or healthy controls who had no history of psychopathology (N=22). Youth completed performance-based measures of attention and interpretation bias. Electrodermal activity was assessed while youth participated in the Trier Social Stress Test for Children (TSST-C; Buske-Kirschbaum, Jobst, & Wustmans, 1997). A mixed models analysis indicated significant linear and non-linear changes in skin conductance, with similar slopes for both groups. Interpretation bias, but not attention bias, moderated the relationship between group status and sympathetic arousal during the TSST-C. Arousal trajectories did not differ for anxious and healthy control youth who exhibited high levels of threat interpretation bias. However, for youth who exhibited moderate and low levels of interpretation bias, the anxious group demonstrated greater arousal slopes than healthy control youth. Results provide initial evidence that the relationship between anxiety status and physiological arousal during stress may be moderated by level of interpretation bias for threat. These findings may implicate interpretation bias as a marker of sympathetic reactivity in youth. Implications for future research and limitations are discussed.

Hypnosis in the Treatment of Major Depression: An Analysis of Heart Rate Variability

Hypnosis is an adjuvant treatment of major depression (MD). Heart rate variability (HRV) can assess the autonomic nervous system, which is associated with MD, and HRV is decreased in MD patients. There is a lack of research on HRV changes before, during, and after the use of hypnosis in MD patients. A total of 21 MD patients participated in this study, and 5-minute electrocardiograms were recorded before, during, and after hypnosis. Compared with the prehypnotic condition, HRV parameters significantly (p < .01) increased in the hypnotic and posthypnotic conditions. The results suggest that hypnosis treatment should bring some functional improvement to the autonomic nervous system. HRV is potentially a useful tool that quantifies the physiological impact of hypnosis treatment in MD patients.

The influence of physical activity during pregnancy on maternal, fetal or infant heart rate variability: a systematic review

Background

Physical activity (PA) during pregnancy has been shown to be associated with several positive effects for mother, fetus, and offspring. Heart rate variability (HRV) is a noninvasive and surrogate marker to determine fetal overall health and the development of fetal autonomic nervous system. In addition, it has been shown to be significantly influenced by maternal behavior. However, the influence of maternal PA on HRV has not yet been systematically reviewed. Therefore, the aim of this systematic review was to assess the influence of regular maternal PA on maternal, fetal or infant HRV.

Methods

A systematic literature search following a priori formulated criteria of studies that examined the influence of regular maternal PA (assessed for a minimum period of 6 weeks) on maternal, fetal or infant HRV was performed in the databases Pubmed and SPORTDiscus. Quality of each study was assessed using the standardized Quality Assessment Tool for Quantitative Studies (QATQS).

Results

Nine articles were included into the present systematic review: two intervention studies, one prospective longitudinal study, and six post-hoc analysis of subsets of the longitudinal study. Of these articles four referred to maternal HRV, five to fetal HRV, and one to infant HRV. The overall global rating for the standardized quality assessment of the articles was moderate to weak. The articles regarding the influence of maternal PA on maternal HRV indicated contrary results. Five of five articles regarding the influence of maternal PA on fetal HRV showed increases of fetal HRV on most parameters depending on maternal PA. The article referring to infant HRV (measured one month postnatal) showed an increased HRV.

Conclusions

Based on the current evidence available, our overall conclusion is that the hypothesis that maternal PA influences maternal HRV cannot be supported, but there is a trend that maternal PA might increase fetal and infant HRV (clinical conclusion). Therefore, we recommend that further, high quality studies addressing the influence of maternal PA on HRV should be performed (methodological conclusion).

Reduced power spectra of heart rate variability are correlated with anxiety in patients with mild traumatic brain injury

Anxiety is one of the most frequently diagnosed emotional disorders after a mild traumatic brain injury (mTBI); however, predictors of anxiety after an mTBI remain uncertain. Recent research indicated that anxiety is associated with abnormalities in the autonomic nervous system (ANS) which can be evaluated by a power spectral analysis of heart rate variability (HRV). In this study, we investigated whether a frequency-domain analysis of HRV could correlate with the occurrence of anxiety in mTBI patients. We recruited 165 Taiwanese patients diagnosed with an mTBI and 82 volunteer healthy controls from three affiliated hospitals of Taipei Medical University during 2010-2014. The Beck Anxiety Inventory (BAI) was assessed at the 1st, 6th, and 12th weeks. We found that mTBI patients were more vulnerable to anxiety compared to healthy controls. The power spectral density of HRV was significantly lower in mTBI patients than in healthy controls. A correlation analysis indicated that anxiety was negatively significantly correlated with low- and high-frequency power at the 6th week. Our study suggests the clinical usefulness of HRV as a potential noninvasive tool for evaluating later anxiety in mTBI patients.

Maladaptive mood repair, atypical respiratory sinus arrhythmia, and risk of a recurrent major depressive episode among adolescents with prior major depression

BACKGROUND

Because depressive illness is recurrent, recurrence prevention should be a mainstay for reducing its burden on society. One way to reach this goal is to identify malleable risk factors. The ability to attenuate sadness/dysphoria (mood repair) and parasympathetic nervous system functioning, indexed as respiratory sinus arrhythmia (RSA), are impaired during depression and after it has remitted. The present study therefore tested the hypothesis that these two constructs also may mirror risk factors for a recurrent major depressive episode (MDE).

METHOD

At time 1 (T1), 178 adolescents, whose last MDE had remitted, and their parents, reported on depression and mood repair; youths' RSA at rest and in response to sad mood induction also were assessed. MDE recurrence was monitored until time 2 (T2) up to 2 years later. Mood repair at T1 (modeled as a latent construct), and resting RSA and RSA response to sadness induction (RSA profile), served to predict onset of first recurrent MDE by T2.

RESULTS

Consistent with expectations, maladaptive mood repair predicted recurrent MDE, above and beyond T1 depression symptoms. Further, atypical RSA profiles at T1 were associated with high levels of maladaptive mood repair, which, in turn, predicted increased risk of recurrent MDE. Thus, maladaptive mood repair mediated the effects of atypical RSA on risk of MDE recurrence.

CONCLUSIONS

This study documented that a combination of behavioral and physiological risk factors predicted MDE recurrence in a previously clinically referred sample of adolescents with depression histories. Because mood repair and RSA are malleable, both could be targeted for modification to reduce the risk of recurrent depression in youths.

High frequency heart-rate variability predicts adolescent depressive symptoms, particularly anhedonia, across one year

BACKGROUND

Few prospective studies examine the link between lower heart rate variability (HRV) and depression symptoms in adolescents. A recent animal model specifically links HRV to anhedonia, suggesting a potential translational model for human research.

METHOD

We investigated the association between spectral measures of resting HRV and depressive symptoms measured one year later, among 73 adolescents, aged 11-18 years. We evaluated (1) the predictive power of relative high frequency (HF) HRV, relative low frequency (LF) and relative very low frequency (VLF) HRV for depressive symptoms; and (2) the relative strength of association between HF HRV and depressive symptomatology (anhedonia, negative mood, interpersonal problems, ineffectiveness, negative self-esteem).

RESULTS

HF HRV significantly predicted self-reported depressive symptoms across one year, controlling for age, puberty and sex. HF HRV was most strongly associated with anhedonia one year later, after considering other facets of depressive symptomatology.

CONCLUSIONS

Results provide support for the prospective relationship between relative HF HRV and depressive symptoms among adolescents across one year. Findings concur with rodent models that suggest a specific link between HF HRV and anhedonia.

LIMITATIONS

We investigated relative spectral power HF HRV and depressive symptom dimensions. We cannot make strong claims about these associations in clinical depression. Physical activity levels could be controlled in future work.

The Association between Baseline Subjective Anxiety Rating and Changes in Cardiac Autonomic Nervous Activity in Response to Tryptophan Depletion in Healthy Volunteers

The aim of this study was to investigate the influence of serotonin on anxiety and autonomic nervous system (ANS) function; the correlation between subjective anxiety rating and changes of ANS function following tryptophan depletion (TD) in healthy volunteers was examined. Twenty-eight healthy participants, consisting of 15 females and 13 males, with an average age of 33.3 years, were recruited.Baseline Chinese Symptom Checklist-90-Revised and ANS function measurements were taken. TD was carried out on the testing day, and participants provided blood samples right before and 5 hours after TD. ANS function, somatic symptoms, and Visual Analogue Scales (VASs) were determined after TD. Wilcoxon signed rank test and Spearman ρ correlation were adapted for analyses of the results.The TD procedure reduced total and free plasma tryptophan effectively. After TD, the sympathetic nervous activity increased and parasympathetic nervous activity decreased. Baseline anxiety ratings positively correlated with post-TD changes in sympathetic nervous activity, VAS ratings, and physical symptoms. However, a negative correlation with post-TD changes in parasympathetic nervous activity was found.The change in ANS function after TD was associated with the severity of anxiety in healthy volunteers. This supports the fact that the effect of anxiety on heart rate variability is related to serotonin vulnerability. Furthermore, it also shows that the subjective anxiety rating has a biological basis related to serotonin.

Hippotherapy acute impact on heart rate variability non-linear dynamics in neurological disorders

Neurological disorders are associated with autonomic dysfunction. Hippotherapy (HT) is a therapy treatment strategy that utilizes a horse in an interdisciplinary approach for the physical and mental rehabilitation of people with physical, mental and/or psychological disabilities. However, no studies have been carried out which evaluated the effects of HT on the autonomic control in these patients. Therefore, the objective of the present study was to investigate the effects of a single HT session on cardiovascular autonomic control by time domain and non-linear analysis of heart rate variability (HRV). The HRV signal was recorded continuously in twelve children affected by neurological disorders during a HT session, consisting in a 10-minute sitting position rest (P1), a 15-minute preparatory phase sitting on the horse (P2), a 15-minute HT session (P3) and a final 10-minute sitting position recovery (P4). Time domain and non-linear HRV indices, including Sample Entropy (SampEn), Lempel-Ziv Complexity (LZC) and Detrended Fluctuation Analysis (DFA), were calculated for each treatment phase. We observed that SampEn increased during P3 (SampEn=0.56±0.10) with respect to P1 (SampEn=0.40±0.14, p<0.05), while DFA decreased during P3 (DFA=1.10±0.10) with respect to P1 (DFA=1.26±0.14, p<0.05). A significant SDRR increase (p<0.05) was observed during the recovery period P4 (SDRR=50±30ms) with respect to the HT session period P3 (SDRR=30±10ms). Our results suggest that HT might benefit children with disabilities attributable to neurological disorders by eliciting an acute autonomic response during the therapy and during the recovery period.

Parasympathetic nervous system activity predicts mood repair use and its effectiveness among adolescents with and without histories of major depression

Depressive disorders that onset in the juvenile years have been linked to far-reaching adverse consequences, making it imperative to elucidate key mechanisms and contributory factors. Excessive use of regulatory responses that exacerbate sadness (maladaptive mood repair) or insufficient use of regulatory responses that reduce it (adaptive mood repair) may reflect behavioral mechanisms of depression risk. Cardiac vagal control, indexed by patterns of respiratory sinus arrhythmia (RSA), has received attention as a putative physiological risk factor for depression. Although mood repair and RSA are related, the nature of this relationship is not well characterized in the context of depression risk. Therefore, we tested alternative models of the relationships between RSA patterns (at rest and in response to a sad film), trait mood repair, and the effectiveness of a mood repair response in the laboratory (state mood repair) among adolescents with depression histories (n = 210) and emotionally healthy peers (n = 161). In our data, a mediation model best explained the association between the key constructs: Adolescents with normative RSA patterns exhibited lower levels of depression and trait maladaptive mood repair, and benefited more from instructed (state) mood repair in the laboratory. By contrast, adolescents with atypical RSA patterns exhibited higher levels of depression and dispositional maladaptive mood repair, which, in turn, mediated the relations of RSA patterns and depression symptoms. Atypical RSA patterns also predicted reduced benefits from laboratory mood repair.