Autonomic Nervous System Regulation Research Articles

Acquirement of the autonomic nervous system modulation evaluated by heart rate variability in medaka (Oryzias latipes).

Small teleosts have recently been established as models of human diseases. However, measuring heart rate by electrocardiography is highly invasive for small fish and not widely used. The physiological nature and function of vertebrate autonomic nervous system (ANS) modulation of the heart has traditionally been investigated in larvae, transparent but with an immature ANS, or in anesthetized adults, whose ANS activity may possibly be disturbed under anesthesia. Here, we defined the frequency characteristics of heart rate variability (HRV) modulated by the ANS from observations of heart movement in high-speed movie images and changes in ANS regulation under environmental stimulation in unanesthetized adult medaka (Oryzias latipes). The HRV was significantly reduced by atropine (1 mM) in the 0.25-0.65 Hz and by propranolol (100 μM) at 0.65-1.25 Hz range, suggesting that HRV in adult medaka is modulated by both the parasympathetic and sympathetic nervous systems within these frequency ranges. Such modulations of HRV by the ANS in adult medaka were remarkably suppressed under anesthesia and continuous exposure to light suppressed HRV only in the 0.25-0.65 Hz range, indicating parasympathetic withdrawal. Furthermore, pre-hatching embryos did not show HRV and the power of HRV developed as fish grew. These results strongly suggest that ANS modulation of the heart in adult medaka is frequency-dependent phenomenon, and that the impact of long-term environmental stimuli on ANS activities, in addition to development of ANS activities, can be precisely evaluated in medaka using the presented method.

An Artificial Autonomic Nervous System That Implements Heart and Pupil as Controlled by Artificial Sympathetic and Parasympathetic Nerves

AbstractThe autonomic nervous system maintains homeostasis in organisms through complex neural pathways and responds adaptively to changes in the external and internal environment. The fabrication of an artificial autonomic nervous system is reported that replicates combined effects of sympathetic and parasympathetic nerves on cardiac activity and pupillary control, to mimic the regulation of autonomic nervous system to external changes. The artificial autonomic nerve‐controlled pupil contraction and relaxation, modulating the rate of heartbeats for normal cardiac rhythm and arrhythmia as reflected by blink rates of a signal indicator. These functions are switched by using a parallel‐channeled synaptic transistor with a special n‐i‐p heterostructure that has a 2D h‐BN insulator in the middle to provide barrier against ion injection into the 2D MoS2 bottom n‐channel and enable short‐term plasticity as induced by acetylcholine, and the electrochemical doping reaction occurred at the P3HT nanowire p‐channels on top to enable relatively long‐term plasticity as induced by noradrenaline. Low‐energy consumption down to femtojoule and an ultrahigh paired‐pulse facilitation index up to ≈455% are demonstrated. An artificial neural network based on device characteristics achieves a high recognition accuracy for electrocardiogram patterns. This study extends insights into artificial nerves‐inspired biological signal processing and recognition.

Changes in Dynamic Stability of Cardiovascular Time Series by Local Largest Lyapunov Exponent in the Time-Frequency Domain in Vasovagal Syncope

Orthostatic stress via a head-up tilt test (HUTT) has been clinically used to rule out vasovagal syncope (VVS), which is generated by an inappropriate autonomic nervous system (ANS) regulation. VVS has been evaluated mainly by hemodynamic variables and linear analysis of heart rate variability. In this study, the estimation of the local largest Lyapunov exponent (LLE[Formula: see text] was used to assess the predictability of the beat-to-beat interval (BBI), systolic (SBP), and diastolic blood pressure (DBP) times series to analyze in a nonlinear and time-varying fashion the impact of HUTT on ANS regulation in young females, healthy and patients with VVS. The estimation of LLEL of the time series was achieved in both the original domain (full-band) and narrow-band signals by the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN). Results pointed out that during the orthostatic phase (OPH), the VVS patients showed: (1) significantly higher predictability (less complexity) of the BBI time series, i.e., significant altered cardiac vagal modulation, (2) less predictability of SBP variability suggesting altered sympathetic modulation to the vasculature, and (3) LLEL in conjunction with CEEMDAN evidenced an impairment of cardiovascular autonomic control.

The autonomic nervous system: A potential link to the efficacy of acupuncture.

The autonomic nervous system (ANS) is a diffuse network that regulates physiological systems to maintain body homeostasis by integrating inputs from the internal and external environment, including the sympathetic, parasympathetic, and enteric nervous systems (ENS). Recent evidence suggests that ANS is one of the key neural pathways for acupuncture signal transduction, which has attracted worldwide attention in the acupuncture field. Here, we reviewed the basic and clinical research published in PubMed over the past 20 years on the effects of acupuncture on ANS regulation and homeostasis maintenance. It was found that acupuncture effectively alleviates ANS dysfunction-associated symptoms in its indications, such as migraine, depression, insomnia, functional dyspepsia, functional constipation. Acupuncture stimulation on some specific acupoints activates sensory nerve fibers, the spinal cord, and the brain. Using information integration and efferents from a complex network of autonomic nuclei of the brain, such as the insular cortex (IC), prefrontal cortex, anterior cingulate cortex (ACC), amygdala (AMG), hypothalamus, periaqueductal gray (PAG), nucleus tractus solitarius (NTS), ventrolateral medulla (VLM), nucleus ambiguus (AMB), acupuncture alleviates visceral dysfunction, inflammation via efferent autonomic nerves, and relieves pain and pain affect. The modulating pattern of sympathetic and parasympathetic nerves is associated with acupuncture stimulation on specific acupoints, intervention parameters, and disease models, and the relationships among them require further exploration. In conclusion, ANS is one of the therapeutic targets for acupuncture and mediates acupuncture's actions, which restores homeostasis. A systemic study is needed to determine the rules and mechanisms underlying the effects of acupoint stimulation on corresponding organs mediated by specific central nervous networks and the efferent ANS.

Autonomic Nervous System Regulation of Epicardial Adipose Tissue: Potential Roles for Regulator of G Protein Signaling-4.

The epicardial adipose tissue (EAT) or epicardial fat is a visceral fat depot in the heart that contains intrinsic adrenergic and cholinergic nerves, through which it interacts with the cardiac sympathetic (adrenergic) and parasympathetic (cholinergic) nervous systems. These EAT nerves represent a significant source of several adipokines and other bioactive molecules, including norepinephrine, epinephrine, and free fatty acids. The production of these molecules is biologically relevant for the heart, since abnormalities in EAT secretion are implicated in the development of pathological conditions, including coronary atherosclerosis, atrial fibrillation, and heart failure. Sympathetic hyperactivity and parasympathetic (cholinergic) derangement are associated with EAT dysfunction, leading to a variety of adverse cardiac conditions, such as heart failure, diastolic dysfunction, atrial fibrillation, etc.; therefore, several studies have focused on exploring the autonomic regulation of EAT as it pertains to heart disease pathogenesis and progression. In addition, Regulator of G protein Signaling (RGS)-4 is a protein with significant regulatory roles in both adrenergic and muscarinic receptor signaling in the heart. In this review, we provide an overview of the autonomic regulation of EAT, with a specific focus on cardiac RGS4 and the potential roles this protein plays in this regulation.

Functional state in young wrestlers with different latency of visual response

The aim of the work is research of functional state in young wrestlers with different latency of visual response. 30 younger wrestlers age 14-16 were examined. The functional sates of wrestlers were studied by complex methods. The results are show that slow of time latency in young wrestler links with the emotional promotion and activation of parasympathetic tone of autonomic nervous system regulation.

Relationship between Body Composition and Cardiac Autonomic Regulation in a Large Population of Italian Olympic Athletes.

Athletic performance is determined by many factors, such as cardiorespiratory fitness, muscular strength and psychological features, which all interact simultaneously. The large Italian National Olympic Committee database of Olympic athletes offers a unique healthy population to verify the strength of the interplay among a number of major elements of training, including autonomic nervous system (ANS) modulation, biochemical indicators and body composition, in a system medicine approach. This observational, retrospective study involved 583 individuals. As part of the yearly precompetitive examination, cardiac autonomic (heart rate variability), psychological, physical (cycloergometer stress test), biochemical and body composition (BOD POD) evaluations were performed. In subsequent analysis, we first considered the relationship between body composition and single individual variables in a simple correlation matrix, including a multitude of variables; then, Exploratory Factor Analysis (EFA) restricted the information to six latent domains, each combining congruent information in relation to body composition. Finally, we employed a multiple quantile regression model to evaluate possible relationships between ANSIs (index capable of synthetizing ANS regulation) and the latent domains indicated by EFA reflecting body composition. We observed a clear relationship between ANS and body mass composition parameters, as indicated by both bivariate correlations and the quantile regression result of ANSIs versus the latent domain aggregating mainly body composition data expressed in % (p = 0.002). In conclusion, these results suggest that specific training may elicit parallel adaptation of ANS control and body composition. The analysis of Olympic athletes’ data allowed us to obtain a better understanding of the complex, multidimensional factors involved in determining sport performance. The latter appears to be determined by the simultaneous interaction not only of cardiorespiratory fitness, muscular strength and psychological features, but also of ANS cardiovascular modulation and body composition.

Progressive Additive Benefits of Prehabilitation and Subsequent Bariatric Surgery on Cardiac Autonomic Regulation as Assessed by Means of a Simple Unitary Composite Index: Preliminary Data from an Observational Study.

Obesity is associated with an increased risk of several chronic comorbidities, which may also be determined by dysfunctional autonomic nervous system (ANS). The influence of bariatric surgery (BS) on ANS balance was explored in previous studies, but with high heterogeneity in both the assessment timing and methods employed. In the present observational study, we applied a clinical protocol which considers two subsequent phases. Twenty-nine non-diabetic obese subjects were studied at baseline (T0), after one month of lifestyle modification (prehabilitation) (phase 1-T1), and after eight months following BS (phase 2-T2). ANS regulation was assessed across the three study epochs by means of ANSI, a single composite percent-ranked proxy of autonomic balance, being free of gender and age bias, economical and simple to apply in a clinical setting. The aim of the present study was to investigate the effects of the clinical protocol based on prehabilitation and subsequent BS on the ANS regulation by means of ANSI. Potential intertwined correlations with metabolic parameters were also investigated. Notably, we observed a progressive improvement in ANS control, even by employing ANSI. Moreover, the reduction in the markers of sympathetic overactivity was found to significantly correlate with the amelioration in some metabolic parameters (fasting glucose, insulin levels, and waist circumference), as well as in stress and tiredness perception. In conclusion, this study provides convincing evidence that a unitary proxy of cardiac autonomic regulation (CAR) may reflect the progressive improvement in autonomic regulation following behavioral and surgical interventions in obese patients. Intriguingly, this might contribute to reducing cardiovascular and metabolic risk.

Autonomic Nervous System Indices of Player Readiness During Elite-Level Rugby Union Game-Week Microcycles.

Grainger, A, Heffernan, S, Waldron, M, and Sawczuk, T. Autonomic nervous system indices of player readiness during elite-level rugby union game-week microcycles. J Strength Cond Res 36(11): 3173-3178, 2022-Elite-level rugby union (RU) is a high-intensity contact sport that involves large training and match volumes across a season, which can lead to postmatch fatigue. Autonomic nervous system (ANS) regulation and perceived fatigue have been suggested to relate to measures of training and match load in RU. However, there have been no studies to assess specific ANS variables in elite RU during in-season microcycles. Player readiness during game-week microcycles was measured via heart rate variability (HRV) indices, direct current potential and self-reported well-being among 13, elite, male RU players. To enable comparison, data collection days were categorized in relation to their proximity to match day, ranging from match day minus 3 (MD - 3), to match day plus 3 (MD + 3). Differences between match days were evaluated using general linear models and Cohen's d effect sizes. There were significant differences between MD and MD + 1 for ANS indices (RMSSD p = 0.04, d = -0.66, 95% CI 0.11-1.20; the standard deviation of NN intervals p = 0.04, d = -0.66, 95% CI 0.12-1.20; total power p = 0.05, d = -0.65, 95% CI 0.11-1.20) and wellness measures (readiness p = 0.18; d = -2.33, 95% CI, 1.54-3.13; energy p = 0.02; d = -2.24, 95% CI 1.44-3.03; soreness p = 0.00; d = -2.42, 95% CI 1.63-3.23). Match day plus 3 effects were significantly greater than MD + 1 in several ANS responses, with wellness recovering at a slower time-course than ANS responses. Measures of HRV are dysregulated postmatch, but based on their rapid recovery thereafter, using HRV to assess readiness of elite-level players in RU across a weekly microcycle could be limited and requires further investigation.

Crosstalk between Schizophrenia and Metabolic Syndrome: The Role of Oxytocinergic Dysfunction.

The high prevalence of metabolic syndrome in persons with schizophrenia has spurred investigational efforts to study the mechanism beneath its pathophysiology. Early psychosis dysfunction is present across multiple organ systems. On this account, schizophrenia may be a multisystem disorder in which one organ system is predominantly affected and where other organ systems are also concurrently involved. Growing evidence of the overlapping neurobiological profiles of metabolic risk factors and psychiatric symptoms, such as an association with cognitive dysfunction, altered autonomic nervous system regulation, desynchrony in the resting-state default mode network, and shared genetic liability, suggest that metabolic syndrome and schizophrenia are connected via common pathways that are central to schizophrenia pathogenesis, which may be underpinned by oxytocin system dysfunction. Oxytocin, a hormone that involves in the mechanisms of food intake and metabolic homeostasis, may partly explain this piece of the puzzle in the mechanism underlying this association. Given its prosocial and anorexigenic properties, oxytocin has been administered intranasally to investigate its therapeutic potential in schizophrenia and obesity. Although the pathophysiology and mechanisms of oxytocinergic dysfunction in metabolic syndrome and schizophrenia are both complex and it is still too early to draw a conclusion upon, oxytocinergic dysfunction may yield a new mechanistic insight into schizophrenia pathogenesis and treatment.

Heart rate (HR) and heart rate variability (HRV) response to inhaled N, N-dimethyltryptamine (N, N-DMT): A case report

Abstract Background N, N-Dimethyltryptamine (N, N-DMT) is a naturally occurring tryptamine-based alkaloid and classic psychedelic. The potent psychoactive properties of N, N-DMT are mediated by serotonin 2A (5-HT2A) receptor agonism. There are limited investigations into the physiologic effects of inhaled N, N-DMT, despite this being one of the most common routes of administration. Heart rate variability (HRV) is an emergent non-invasive marker of cardiac autonomic nervous system (ANS) regulation and reductions in HRV have been negatively associated with multiple health outcomes. Methods A case is described with a brief review of supportive findings. Results Heart rate (HR) and HRV responses following three naturalistic inhaled N, N-DMT experiences were documented in a healthy 31-year-old male. Acute transient elevations in HR immediately following N, N-DMT administration and a pronounced elevation in the average daily HRV one-day following the experiences were observed. The duration of experience shortened across the three experiences despite similar N, N-DMT doses. Conclusion These findings offer preliminary evidence into the effect of inhaled N, N-DMT on HR and HRV. Given the emergent understanding of reductions in HRV as a hazardous marker of stress, psychiatric conditions, and mental health outcomes, further research into the effects of psychedelics on HRV is warranted.

Examining the Autonomic Nervous System in the Relationship among Heart Rate Variability, Stress Coping, and Cognitive Ability in Individuals with Psychiatric Disorders.

Depression is one of the most severe psychiatric disorders and affects patients on emotional, physical, and cognitive levels. Comorbid somatic conditions, such as cardiovascular diseases, are frequent and affect the quality of life, as well as mortality. Underlying maladaptive autonomic nervous system regulation influences emotional and cognitive processes. This study, thus, aimed to investigate the relationship among heart rate variability (HRV), self-reported coping strategies, executive function, and inhibition in individuals with psychiatric disorders. Data of 97 patients treated in a multi-professional psychiatric rehabilitation center for 6 weeks were analyzed. Subjects underwent psychological tests (Stress Coping Style Questionnaire, Emotional Competence Questionnaire, and Becks Depression Inventory-II), a cognitive test (Color-Word Interference Test), and a 24 h electrocardiogram to record HRV. Patients with higher depression scores had significantly lower HRVs and decreased self-reported abilities for stress coping. Depression severity did not affect cognitive inhibitory abilities. HRV was related to neither coping strategies nor cognitive inhibition abilities. However, lower HRV was related to higher values of Negative Stress Coping (β = −0.21, p < 0.05). This relationship was fully mediated by depression severity (−4.79, 95% CI: −8.72, −0.72). HRV is not related to quantitative cognitive inhibition, but to the self-reported ability to cope with negative emotions in individuals with psychiatric disorders.

Peak Detection and HRV Feature Evaluation on ECG and PPG Signals

Heart Rate Variability (HRV) evaluates the autonomic nervous system regulation and can be used as a monitoring tool in conditions such as cardiovascular diseases, neuropathies and sleep staging. It can be extracted from the electrocardiogram (ECG) and the photoplethysmogram (PPG) signals. Typically, the HRV is obtained from the ECG processing. Being the PPG sensor widely used in clinical setups for physiological parameters monitoring such as blood oxygenation and ventilatory rate, the question arises regarding the PPG adequacy for HRV extraction. There is not a consensus regarding the PPG being able to replace the ECG in the HRV estimation. This work aims to be a contribution to this research area by comparing the HRV estimation obtained from simultaneously acquired ECG and PPG signals from forty subjects. A peak detection method is herein introduced based on the Hilbert transform: Hilbert Double Envelope Method (HDEM). Two other peak detector methods were also evaluated: Pan-Tompkins and Wavelet-based. HRV parameters for time, frequency and the non-linear domain were calculated for each algorithm and the Pearson correlation, T-test and RMSE were evaluated. The HDEM algorithm showed the best overall results with a sensitivity of 99.07% and 99.45% for the ECG and the PPG signals, respectively. For this algorithm, a high correlation and no significant differences were found between HRV features and the gold standard, for the ECG and PPG signals. The results show that the PPG is a suitable alternative to the ECG for HRV feature extraction.

Neurocognitive monitoring in congenital central hypoventilation syndrome with the NIH Toolbox®.

Congenital central hypoventilation syndrome (CCHS) is a rare neurocristopathy, caused by mutations in the paired‐like homeobox gene PHOX2B, which alters control of breathing and autonomic nervous system regulation, necessitating artificial ventilation as life‐support. A broad range of neurocognitive performance has been reported in CCHS, including an array of cognitive deficits. We administered the NIH Toolbox® Cognition Battery (NTCB), a novel technology comprised of seven tasks presented via an interactive computer tablet application, to a CCHS cohort and studied its convergent and divergent validity relative to traditional clinical neurocognitive measures. The NTCB was administered to 51 CCHS participants, including a subcohort of 24 who also received traditional clinical neurocognitive testing (Wechsler Intelligence Scales). Age‐corrected NTCB scores from the overall sample and subcohort were compared to population norms. Associations between NTCB indices and Wechsler Intelligence scores were studied to determine the convergent and divergent validity of the NTCB. NTCB test results indicated reduced Fluid Cognition, which measures new learning and speeded information processing (p < 0.001), but intact Crystallized Cognition, which measures past learning, in CCHS relative to population norms. Moderate to strong associations (r > 0.60) were found between age‐corrected NTCB Fluid and Crystallized indices and comparable Wechsler indices, supporting the convergent and discriminant validity of the NTCB. Results reveal deficits of Fluid Cognition in individuals with CCHS and indicate that the NTCB is a valid and sensitive measure of cognitive outcomes in this population. Our findings suggest that the NTCB may play a useful role in tracking neurocognition in CCHS.

The effects of noninvasive brain stimulation on heart rate and heart rate variability: A systematic review and meta-analysis.

Noninvasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation and transcranial direct current stimulation are widely used to test the involvement of specific cortical regions in various domains such as cognition and emotion. Despite the capability of stimulation techniques to test causal directions, this approach has been only sparsely used to examine the cortical regulation of autonomic nervous system (ANS) functions such as heart rate (HR) and heart rate variability (HRV) and to test current models in this regard. In this preregistered (PROSPERO) systematic review and meta-analysis, we aimed to investigate, based on meta-regression, whether NIBS represents an effective method for modulating HR and HRV measures, and to evaluate whether the ANS is modulated by cortical mechanisms affected by NIBS. Here we have adhered to the PRISMA guidelines. In a series of four meta-analyses, a total of 131 effect sizes from 35 sham-controlled trials were analyzed using robust variance estimation random-effects meta-regression technique. NIBS was found to effectively modulate HR and HRV with small to medium effect sizes. Moderator analyses yielded significant differences in effects between stimulation of distinct cortical areas. Our results show that NIBS is a promising tool to investigate the cortical regulation of ANS, which may add to the existing brain imaging and animal study literature. Future research is needed to identify further factors modulating the size of effects. As many of the studies reviewed were found to be at high risk of bias, we recommend that methods to reduce potential risk of bias be used in the design and conduct of future studies.

Autonomic nervous system dysregulation in response to postural change in patients with pectus excavatum in Taiwan: a pilot study

BackgroundPectus excavatum (PE) negatively impacts psychological function, but its effect on autonomic nervous system (ANS) function has not been investigated. We evaluated ANS function following postural changes in patients with PE.MethodsThe participants were 14 healthy men (control group) and 20 men with PE (study group). Psychological function was assessed using the visual analog scale for pain, Brief Symptom Rating Scale-5, and Beck Depression Inventory-II. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI). ANS regulation in response to postural change was measured in the supine position and immediately after sitting. All measurements were compared between the control and study groups at baseline and between the study groups before and after Nuss surgery.ResultsAt baseline, upon postural change, symptomatic activity increased in the control group (50.3–67.4%, p = 0.035) but not in the study group (55.0–54.9%, p = 0.654); parasympathetic activity decreased in the control group (49.7–32.6%, p = 0.035) but not in the study group (45.1–45.1%, p = 0.654); and overall ANS regulation increased in the control group (1.02–2.08, p = 0.030) but not in the study group (1.22–1.22, p = 0.322). In response to postural change after Nuss surgery in the study group, sympathetic activity increased (48.7–70.2%, p = 0.005), parasympathetic activity decreased (51.3–29.8%, p = 0.005), and overall ANS regulation increased (0.95–2.36, p = 0.012).ConclusionANS function in response to postural change is dysregulated in patients with PE, which improved after Nuss surgery.Trial registration ClinicalTrials.gov, ID: NCT03346876, November 15, 2017, retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0007KGI&selectaction=Edit&uid=U0003JZU&ts=2&cx=cstxeg

Maternal Sensitivity Modulates Child's Parasympathetic Mode and Buffers Sympathetic Activity in a Free Play Situation.

BackgroundBehavioral and physiological (self-)regulation in early life is crucial for the understanding of childhood development and adjustment. The autonomic nervous system (ANS) is a main player in the regulative system and should therefore be modulated by the quality of interactive behavior of the caregiver. We experimentally investigated the ANS response of 18–36-month-old children in response to the quality of maternal behavior during a mother–child-interacting paradigm.MethodEighty mothers and their children came to our laboratory and took part in an experimental paradigm, consisting of three episodes: a resting phase (E1), a structured play phase (E2), and a free play situation (E3) between mothers and their child. Children’s and mother’s heart rate (HR), the sympathetic nervous system (SNS) activity via the pre-ejection period (PEP) and the left ventricular ejection time (LVET), and the parasympathetic nervous system (PNS) activity via the respiratory sinus arrhythmia (RSA) were continuously measured by an electrocardiogram. Maternal sensitivity of interactive behavior was assessed by using the Emotional Availability (EA) Scales.ResultsChildren of mothers with insensitive behavior had a significantly lower RSA at baseline, showed a lack of RSA withdrawal during structured and free play, and had shorter LVET across all episodes compared to children of sensitive mothers.ConclusionOur findings depict the influence of low-quality maternal interaction on the child’s ANS regulation, in calm and more stressful play situations. The overall higher SNS mode with impaired PNS reactivity may negatively influence child’s ANS homoeostasis, which may result in a long-term impact on mental and physical wellbeing. Further, the maternal sensitivity may function as a buffer for the stress response of their child. These results could serve as a basis for the development of appropriate psychoeducational programs for mothers of low sensitivity in their interaction with the child.

Prenatal smoking and drinking are associated with altered newborn autonomic functions.

Prenatal smoking and drinking are associated with sudden infant death syndrome and neurodevelopmental disorders. Infants with these outcomes also have altered autonomic nervous system (ANS) regulation. We examined the effects of prenatal smoking and drinking on newborn ANS function. Pregnant women were enrolled in Northern Plains, USA (NP) and Cape Town (CT), South Africa. Daily drinking and weekly smoking data were collected prenatally. Physiological measures were obtained during sleep 12-96 h post-delivery. In all, 2913 infants from NP and 4072 from CT were included. In active sleep, newborns of mothers who smoked throughout pregnancy, compared to non-smokers, had higher breathing rates (2.2 breaths/min; 95% CI: 0.95, 3.49). Quit-early smoking was associated with reductions in beat-to-beat heart rate variability (HRV) in active (-0.08 s) and quiet sleep (-0.11 s) in CT. In girls, moderate-high continuous smoking was associated with increased systolic (3.0 mmHg, CI: 0.70, 5.24) and diastolic blood pressure (2.9 mmHg, CI: 0.72, 5.02). In quiet sleep, low-continuous drinking was associated with slower heart rate (-4.5 beat/min). In boys, low-continuous drinking was associated with a reduced ratio of low-to-high frequency HRV (-0.11, CI: -0.21, -0.02). These findings highlight potential ANS pathways through which prenatal drinking and smoking may contribute to neurodevelopment outcomes. In this prospective cohort study of 6985 mother-infant dyads prenatal drinking and smoking were associated with multiple ANS parameters. Smoking was associated with increased neonatal breathing rates among all infants, and heart rate variability (HRV) and blood pressure (BP) among girls. Drinking was associated with reductions in HR and BP among all newborns, and reductions in the ratio of low to-high frequency HRV among boys. These findings suggest that prenatal smoking and drinking alter newborn ANS which may presage future neurodevelopmental disorders.

On the spatial phase distribution of cutaneous low-frequency perfusion oscillations

Distributed cutaneous tissue blood volume oscillations contain information on autonomic nervous system (ANS) regulation of cardiorespiratory activity as well as dominating thermoregulation. ANS associated with low-frequency oscillations can be quantified in terms of frequencies, amplitudes, and phase shifts. The relative order between these faculties may be disturbed by conditions colloquially termed ‘stress’. Photoplethysmography imaging, an optical non-invasive diagnostic technique provides information on cutaneous tissue perfusion in the temporal and spatial domains. Using the cold pressure test (CPT) in thirteen healthy volunteers as a well-studied experimental intervention, we present a method for evaluating phase shifts in low- and intermediate frequency bands in forehead cutaneous perfusion mapping. Phase shift changes were analysed in low- and intermediate frequency ranges from 0.05 Hz to 0.18 Hz. We observed that time waveforms increasingly desynchronised in various areas of the scanned area throughout measurements. An increase of IM band phase desynchronization observed throughout measurements was comparable in experimental and control group, suggesting a time effect possibly due to overshooting the optimal relaxation duration. CPT triggered an increase in the number of points phase-shifted to the reference that was specific to the low frequency range for phase-shift thresholds defined as π/4, 3π/8, and π/2 rad, respectively. Phase shifts in forehead blood oscillations may infer changes of vascular tone due to activity of various neural systems. We present an innovative method for the phase shift analysis of cutaneous tissue perfusion that appears promising to assess ANS change processes related to physical or psychological stress. More comprehensive studies are needed to further investigate the reliability and physiological significance of findings.

IDF21-0409 Hypoglycemia and heart rate variability: synchronous detection by Holter and continuous glucose monitors

Background: Hypoglycemia is a notorious diabetic side effect leading to unwanted major vascular events and sudden cardiac death due to change in autonomic cardiac function. Previous studies have reported electrocardiographic (ECG) abnormalities such as QT interval prolongation in patients with hypoglycemia, so did heart rate variability (HRV). Aim: To document ECG and HRV changes during hypoglycemia and expect to establish a portable device to early detect hypoglycemia in the future. Method: Seventeen participants including ten poor controlled type 2 diabetes, six type 1 diabetes and one Latent autoimmune diabetes in adults (LADA) were enrolled in this study. There were six males and eleven females, aged from 37 to 77 (mean 50.3 ± 12.0) years old, with self-reported duration of diabetes from 6 to 33 (mean 20.8 ± 8.7) years. The mean HbA1c was 8.3 ± 1.4 % on the time of the examination. We used Holter- electrocardiogram (VitalSigns) and continuous glucose monitor (Medtronic) to record ECG waveform, heart rate variability and glucose level with synchronization of time for a duration of seven days. Results: Two of the seventeen participants did not experience hypoglycemia (≦70 mg/dL). The other participants who experienced hypoglycemia revealed, as a whole, a trend of correlation between blood glucose, corrected QT Interval (QTc), and HRV. When the participants experienced hypoglycemia were sub-divided into response and non-response groups according to the appearance of QTc prolongation, significant difference of age was found between two groups, most of them were type 1 diabetic patients. Among 90 events of hypoglycemia, 56 events (62%) presented with increased heart rate and/or Low Frequency/ High Frequency (LF/HF) ratio and /or decreased Root Mean Square of the Successive Differences (RMSSD). Besides, there were a trend of difference of glucose nadir, HRV include heart rate, RMSSD and LF/HF ratio between two groups. Discussion: In this study, Type 1 DM patient and younger age were easier to have QT interval prolongation during hypoglycemia. Besides, increased LF/HF ratio may represent that these group of patients have better regulation of autonomic nervous system. Heart rate variability can be seen during hypoglycemic events in both type 1 and type 2 diabetic patients especially in the response group.