High Frequency Band Power Research Articles

Continuous Monitoring of Heart Rate Variability and Respiration for the Remote Diagnosis of Chronic Obstructive Pulmonary Disease: Prospective Observational Study.

Conventional daytime monitoring in a single day may be influenced by factors such as motion artifacts and emotions, and continuous monitoring of nighttime heart rate variability (HRV) and respiration to assist in chronic obstructive pulmonary disease (COPD) diagnosis has not been reported yet. The aim of this study was to explore and compare the effects of continuously monitored HRV, heart rate (HR), and respiration during night sleep on the remote diagnosis of COPD. We recruited patients with different severities of COPD and healthy controls between January 2021 and November 2022. Vital signs such as HRV, HR, and respiration were recorded using noncontact bed sensors from 10 PM to 8 AM of the following day, and the recordings of each patient lasted for at least 30 days. We obtained statistical means of HRV, HR, and respiration over time periods of 7, 14, and 30 days by continuous monitoring. Additionally, the effects that the statistical means of HRV, HR, and respiration had on COPD diagnosis were evaluated at different times of recordings. In this study, 146 individuals were enrolled: 37 patients with COPD in the case group and 109 participants in the control group. The median number of continuous night-sleep monitoring days per person was 56.5 (IQR 32.0-113.0) days. Using the features regarding the statistical means of HRV, HR, and respiration over 1, 7, 14, and 30 days, binary logistic regression classification of COPD yielded an accuracy, Youden index, and area under the receiver operating characteristic curve of 0.958, 0.904, and 0.989, respectively. The classification performance for COPD diagnosis was directionally proportional to the monitoring duration of vital signs at night. The importance of the features for diagnosis was determined by the statistical means of respiration, HRV, and HR, which followed the order of respiration > HRV > HR. Specifically, the statistical means of the duration of respiration rate faster than 21 times/min (RRF), high frequency band power of 0.15-0.40 Hz (HF), and respiration rate (RR) were identified as the top 3 most significant features for classification, corresponding to cutoff values of 0.1 minute, 1316.3 nU, and 16.3 times/min, respectively. Continuous monitoring of nocturnal vital signs has significant potential for the remote diagnosis of COPD. As the duration of night-sleep monitoring increased from 1 to 30 days, the statistical means of HRV, HR, and respiration showed a better reflection of an individual's health condition compared to monitoring the vital signs in a single day or night, and better was the classification performance for COPD diagnosis. Further, the statistical means of RRF, HF, and RR are crucial features for diagnosing COPD, demonstrating the importance of monitoring HRV and respiration during night sleep.

Effects of menstrual cycle on hemodynamic and autonomic responses to central hypovolemia.

Estrogen and progesterone levels undergo changes throughout the menstrual cycle. Existing literature regarding the effect of menstrual phases on cardiovascular and autonomic regulation during central hypovolemia is contradictory. This study aims to explore the influence of menstrual phases on cardiovascular and autonomic responses in both resting and during the central hypovolemia induced by lower body negative pressure (LBNP). This is a companion paper, in which data across the menstrual phases from healthy young females, whose results are reported in Shankwar et al. (2023), were further analysed. The study protocol consisted of three phases: (1) 30 min of supine rest; (2) 16 min of four LBNP levels; and (3) 5 min of supine recovery. Hemodynamic and autonomic responses (assessed via heart rate variability, HRV) were measured before-, during-, and after-LBNP application using Task Force Monitor® (CNSystems, Graz, Austria). Blood was also collected to measure estrogen and progesterone levels. In this companion paper, we have exclusively assessed 14 females from the previous study (Shankwar et al., 2023): 8 in the follicular phase of the menstrual cycle (mean age 23.38 ± 3.58 years, height 166.00 ± 5.78 cm, weight 57.63 ± 5.39 kg and BMI of 20.92 ± 1.96 25 kg/m2) and 6 in the luteal phase (mean age 22.17 ± 1.33 years, height 169.83 ± 5.53 cm, weight 62.00 ± 7.54 kg and BMI of 21.45 ± 2.63 kg/m2). Baseline estrogen levels were significantly different from the follicular phase as compared to the luteal phase: (33.59 pg/ml, 108.02 pg/ml, respectively, p < 0.01). Resting hemodynamic variables showed no difference across the menstrual phases. However, females in the follicular phase showed significantly lower resting values of low-frequency (LF) band power (41.38 ± 11.75 n.u. and 58.47 ± 14.37 n.u., p = 0.01), but higher resting values of high frequency (HF) band power (58.62 ± 11.75 n.u. and 41.53 ± 14.37 n.u., p = 0.01), as compared to females in the luteal phase. During hypovolemia, the LF and HF band powers changed only in the follicular phase F(1, 7) = 77.34, p < 0.0001 and F(1, 7) = 520.06, p < 0.0001, respectively. The menstrual phase had an influence on resting autonomic variables, with higher sympathetic activity being observed during the luteal phase. Central hypovolemia leads to increased cardiovascular and autonomic responses, particularly during the luteal phase of the menstrual cycle, likely due to higher estrogen levels and increased sympathetic activity.

Transcranial Ultrasound Stimulation Improves Memory Performance of Parkinsonian Mice.

Cognitive impairment is one of the most common non-motor symptoms of Parkinson's disease (PD). Previous studies have demonstrated that low-intensity transcranial ultrasound stimulation can significantly suppress the motor symptoms of PD. However, whether ultrasound stimulation can improve cognitive ability in PD and the related neural oscillation mechanism remain unclear to date. To evaluate the effect of ultrasound stimulation on memory ability in PD and explore its neural oscillation mechanism. Ultrasonography was used for 7-day stimulation of the CA1 in transgenic mice with PD. The working memory ability of the PD mice was then tested using novel object discrimination, and the local field potential and spikes in the mice CA1 were recorded at the same time as in the behavioral test. We found that ultrasound stimulation of the PD mice CA1 for 4 days: 1) significantly increased their learning and memory ability, although the learning and memory ability on the 7th day after the stimulation stopped was not significantly different from that before stimulation (P>0.05); 2) significantly increased the relative power of theta, low gamma, and high gamma frequency bands of the local field potential, and the phase amplitude coupling strength between theta and low gamma and between theta and high gamma; and 3) modulated the phase-locking angle between the spike of interneuron and theta wave to a 180°-360° rise cycle. Transcranial ultrasound stimulation can improve the learning and memory abilities of PD mice, and evoking neural oscillations in the CA1 is the potential mechanism.

The Influence of Autonomic Nervous System during Resting State on the Peripheral Pulse Wave Velocity in Young Adult Males

Abstract Background: The association between the activity of autonomic nervous systems (ANS) and pulse wave velocity (PWV) was commonly deduced after adjusting for confounding factors. The relationship between the ANS and PWV was either maintained, but attenuated, or no longer statistically connected after controlling for confounding variables. Research in young healthy individuals showed that the ANS does not control aortic stiffness (indexed by PWV) in a pressure-independent manner. Therefore, the role of the ANS in controlling PWV is debatable. Objectives: The objective of this study was to examine the possibility that ANS directly affects PWV independent of blood pressure (BP) and heart rate (HR). Subjects and Methods: Thirty-four healthy male volunteers (19 years old) were recruited. Stable brachial systolic BP (SBP)/diastolic BP (DBP) and HR were measured in semi-supine position after a 15-min rest. During the last 5 min, fingertip digital pulse wave (DPW) and lead II electrocardiogram (ECG) signals were recorded. The pulse transit time, and consequently PWV, was calculated by measuring the duration between the ECG R wave climax and a reference point on the DPW in the same cardiac cycle. The ANS activity was assessed by calculating the HR variability (HRV) indices obtained from the ECG record of 5-min R-R intervals (RRIs). Results: HRV indices low-frequency (LF)/high-frequency (HF) (LF band power measured in the 0.04–0.15 Hz)/the HF band power measured in the 0.15–0.4 Hz band) and SD2/SD1 ratios (SD1 and SD2 represent the dispersion along the minor and major axis of the fitted ellipse of the Poincaré plot) (sympathovagal balance) were significantly and positively correlated with PWV. In addition, the standard deviation of RRI, or normal-to-normal “NN” (SDNN) interval, after excluding ectopic beats, the square root of the mean squared differences of successive NN intervals (RMSSD) were significantly and negatively correlated with the PWV. No correlation was obtained between PWV and HR, SBP, or DBP. Conclusion: Peripheral PWV during rest or inactivity is affected directly by the sympathovagal balance independent of BP.

Acute Effect of Positive Airway Pressure on Heart Rate Variability in Obstructive Sleep Apnea.

Autonomic dysregulation is associated with cardiovascular consequences in obstructive sleep apnea (OSA). This study aimed to investigate the effect of acute continuous positive airway pressure (CPAP) treatment on autonomic activity and to identify factors contributing to heart rate variability (HRV) changes in OSA. Frequency domain HRV parameters were calculated and compared between the baseline polysomnography and during the CPAP titration in 402 patients with moderate to severe OSA. There were significant reductions in total power, very low-frequency band power, low-frequency band power, and high-frequency band power during the CPAP titration as compared to the baseline polysomnography. This tendency was pronounced in male patients with severe OSA. Multivariate analysis found that changes in the apnea-hypopnea index and oxygen saturation were significantly associated with changes in sympathetic and parasympathetic activity, respectively. This study demonstrated that HRV parameters significantly changed during the CPAP titration, indicating a beneficial effect of CPAP in the restoration of sympathetic and parasympathetic hyperactivity in OSA. Prospective longitudinal studies should determine whether long-term CPAP treatment aids in maintaining the long-lasting improvement of the autonomic functions, thereby contributing to the prevention of cardiovascular and cerebrovascular diseases in patients with OSA.

O010 Capturing Localised Electroencephalography Signals During Sleep using Tripolar Concentric Ring Electrodes

Abstract Introduction Tri -concentric ring electrodes (TCRE) evaluate the current density underlying each electrode and provide improved signal-to-noise compared to conventional electroencephalography (EEG) electrodes. This pilot study used TCRE for the first time to compare TCRE versus more conventional EEG signals during sleep . Materials and Method Twenty healthy sleepers (8 males, mean±SD age 27.8±9.6 y) completed a 9-hr sleep opportunity. Eighteen TCRE electrodes were placed based on the 10-20 system, along with more conventional EEG recorded from the outer rings of paired TCRE electrodes (emulated EEG; eEEG). A Fast Fourier Transform using multitaper-based estimation was applied in 5 second epochs to calculate absolute and relative powers in delta, alpha, theta, sigma and beta frequency bands for eEEG and TCRE signals throughout conventionally scored sleep stages. Results At the Cz position, TCRE showed reduced relative powers in beta frequency bands across sleep stages compared to eEEG. Further, TCRE demonstrated lower relative beta activity during wake (mean difference [95% confidence lower, upper]; -14%, [-15.9%, -12.1%]), N1 sleep (-5.7%, [-7.6%, -3.7%]), and REM sleep (-4.4%, [-6.3%, -2.5%]). TCRE also recorded higher relative delta power across all stages of sleep and wake. Conclusions Lower signal power in high frequency bands and higher power in lower frequency bands supports more favourable signal-to-noise ratio with TCRE compared to more conventional EEG. Thus, TCRE shows promise for evaluating sleep related brain activity. The more focal nature of TCRE recordings may be an additional advantage, that warrants further analysis.

Neural Oscillation Disorder in the Hippocampal CA1 Region of Different Alzheimer's Disease Mice.

Alzheimer's disease (AD) is a well-known neurodegenerative disease that gradually induces neural network dysfunction and progressive memory deficits. Neural network activity is represented by rhythmic oscillations that influence local field potentials (LFPs). However, changes in hippocampal neural rhythmic oscillations in the early stage of AD remain largely unexplored. This study investigated neural rhythmic oscillations in 3-month-old APP/PS1 and 5x- FAD mice to assess early neural connectivity in AD. LFPs were recorded from the hippocampal CA1 region with implanted microelectrode arrays while the mice were in the awake resting stage. Welch fast Fourier transforms, continuous wavelet transforms, and phase-amplitude coupling analyses were used to compute the power density of different frequency bands and phase-amplitude modulation indices in the LFPs. Our results showed impaired theta, low gamma, and high gamma frequency band power in APP/PS1 and 5xFAD mice during the awake resting stage. AD mice also showed decreased delta, alpha, and beta frequency band power. Impaired theta-low gamma and theta-high gamma phaseamplitude coupling were observed in 5xFAD mice. This study revealed neural network activity differences in oscillation power and cross-frequency coupling in the early stage of AD, providing a new perspective for developing biomarkers for early AD diagnosis.

Psychophysiological assessment of trauma-focused Group Music and Imagery therapy for women with PTSD or CPTSD using script-driven imagery. A randomised controlled study.

BackgroundIn posttraumatic stress disorder (PTSD), physiological reactions during trauma scripts have been anchored to the diagnosis. According to the construct of research domain criteria, physiological reactions and self-rating scales could be used to evaluate treatment effects. ObjectiveIn the present study, self-rated PTSD symptoms combined with physiological reactions during trauma script were used as outcome measurements in the domain of arousal/regulatory systems in a controlled randomised study of Group Music and Imagery (GrpMI) treatment for females with PTSD or complex posttraumatic stress disorder (CPTSD) related to violence and/or sexual abuse. Methods45 traumatised women were randomised to 12 weeks of active treatment or waiting. Before and after the intervention, an assessment was done using physiological measurements during script-driven imagery (SDI) procedures. Subjective Units of Distress (SUD) were collected immediately after the trauma script (TS). Reactions during the SDI procedure were reported using the Responses to Script Driven Imagery (RSDI) scale, measuring re-experiencing, avoidance, and dissociation. Self-reported PTSD symptoms were accessed using the PTSD checklist for DSM-5 (PCL-5). Heart rate (HR), heart rate variability (HRV), and electrodermal activity were sampled during the baseline (BL) and TS conditions of the SDI procedure. As a measure of trauma-related reactivity, the difference between TS and BL was used for statistical calculations. HRV measures included high (HF; 0.15-0.4 Hz) and low (LF; 0.03-0.15 Hz) frequency band power, the LF/HF ratio, and the root mean square of successive inter-beat differences (RMSSD). Measures of electrodermal activity included skin conductance levels (SCL) and frequencies of non-specific skin conductance responses (NS-SCR). Further, correlations between self-rated PTSD symptoms and physiological reactivity measures were analysed. ResultsDuring the TS, the absolute levels of HR, LF/HF-ratio, and NS-SCR, as well as the trauma-related reactivity of HR, RMSSD, HF, LF/HF-ratio, SCL, and NS-SCR, showed significant changes indicating decreased arousal during trauma script after treatment. Compared to the waitlist control, an interaction analysis showed significant treatment effects in the BL level of HR, the absolute TS level of HR and HF, and the trauma-related reactivity of RMSSD and HF, suggesting an improvement of vagal function in the treatment group. Significant treatment-related reductions were found in symptoms of PTSD, re-experiencing and avoidance, as well as SUD. The changes pre- to post-treatment in HR reactivity and self-rated PTSD symptoms correlated significantly. Furthermore, the initial HR reactivity predicted treatment outcome as measured with PCL-5. ConclusionIn the evaluation of treatment methods for PTSD, a combination of self-report and physiological measures seems to be feasible. The physiological measures, in combination with a robust decrease in self-rated PTSD symptoms, indicate that trauma-focused GrpMI is a promising treatment for PTSD or CPTSD. More studies are needed to confirm the results, and further research comparing with other active treatments is necessary to establish the precise role of the treatment.

Evaluation of cardiovascular autonomic dysfunction in symptomatic post-COVID-19 patients using the heart rate variability (HRV) and detection of subtle LV dysfunction using 2D global longitudinal strain (GLS)

AimThe COVID-19 disease primarily affects the respiratory system; however, cardiac involvement has been documented in the acute phase. We aimed to evaluate the cardiac autonomic function and subtle left ventricular dysfunction in those subjects recovered from mild to moderate acute COVID-19 patients but still symptomatic.Methods and resultsThe study group was composed of 50 subjects with confirmed mild to moderate COVID-19. All subjects underwent routine 2D echocardiography assessment in addition to 2D speckle tracking and 24 h Holter monitoring for HRV analysis. The mean age of the study population was 42 ± 18 years; symptoms were reported as follows 27 (54%) had dyspnoea, 17 (34%) had palpitation, and 7 (14%) had dizziness. Time domain parameters Standard Deviation of NN intervals (SDNN), Standard Deviation of the Average NN intervals for each 5 min segment of a 24 h HRV recording (SDANN), and Root Mean Square of Successive RR interval Differences (rMSSD) were diminished with mean SDNN value being markedly impaired in 12 (24%) patients, while frequency domain parameters as assessed by the ratio of the Low-Frequency band power to the High-Frequency band power (LF/HF) with the mean of 1.837 with 8% of the patients being impaired. SDNN was significantly reduced in patients with impaired global longitudinal strain (p 0.000). The global longitudinal strain was diminished in 10 patients (20%); also, 80% of the patients with impaired GLS had decreased SDNN.ConclusionOur study targeted patients experiencing prolonged symptoms after COVID-19 illness. We detected a high incidence of GLS impairment using Speckle Tracking Echocardiography (STE) and a significant prevalence of diminished HRV. HRV (especially SDNN) and GLS were found to be significantly correlated.Graphical abstract

Using fMRI to localize target regions for implanted brain-computer interfaces in locked-in syndrome

ObjectiveElectrocorticography (ECoG)-based brain-computer interface (BCI) systems have the potential to improve quality of life of people with locked-in syndrome (LIS) by restoring their ability to communicate independently. Before implantation of such a system, it is important to localize ECoG electrode target regions. Here, we assessed the predictive value of functional magnetic resonance imaging (fMRI) for the localization of suitable target regions on the sensorimotor cortex for ECoG-based BCI in people with locked-in syndrome. MethodsThree people with locked-in syndrome were implanted with a chronic, fully implantable ECoG-BCI system. We compared pre-surgical fMRI activity with post-implantation ECoG activity from areas known to be active and inactive during attempted hand movement (sensorimotor hand region and dorsolateral prefrontal cortex, respectively). ResultsResults showed a spatial match between fMRI activity and changes in ECoG low and high frequency band power (10 – 30 and 65 – 95 Hz, respectively) during attempted movement. Also, we found that fMRI can be used to select a sub-set of electrodes that show strong task-related signal changes that are therefore likely to generate adequate BCI control. ConclusionsOur findings indicate that fMRI is a useful non-invasive tool for the pre-surgical workup of BCI implant candidates. SignificanceIf these results are confirmed in more BCI studies, fMRI might be used for more efficient surgical BCI procedures with focused cortical coverage and lower participant burden.

Vagal cardiac control in rats with LPS-induced lung injury

Heart rate variability (HRV) as an index of cardiac autonomic control in acute lung injury (ALI) has been evaluated in anaesthetized rats intratracheally instilled with bacterial lipopolysaccharide (LPS) and ventilated with breathing frequency of 60/min, 40% oxygen, inspiratory time 40%, tidal volume of 6 mL/kg. ECG was recorded before and 30, 60, 120, 180 and 240 min after LPS or saline (control) administration. HRV was quantified by time and frequency-domain analysis (mean RR interval, SDRR, RMSSD and spectral power in high frequency (HF) band. Lactate in plasma, and oxidative stress, IL-1β, IL-5, IL-12p70 and IL-13 and galectin-3 in heart tissue raised in LPS-injured rats. Overall HRV magnitude (SDRR) and marker of vagal heart rate control (RMSSD), as well as frequency domain parameter, spectral power HF was increased 120 and 180 min since ALI onset. In conclusion, LPS-induced ALI is accompanied by altered vagal cardiac control mediated by autonomic nervous system, likely based on the close relationship between immune response and vagally mediated autonomic nervous activity.

Obstructive sleep apnoea-related respiratory events and desaturation severity are associated with the cardiac response.

BackgroundObstructive sleep apnoea (OSA) causes, among other things, intermittent blood oxygen desaturations, increasing the sympathetic tone. Yet the effect of desaturations on heart rate variability (HRV), a simple and noninvasive method for assessing sympathovagal balance, has not been comprehensively studied. We aimed to study whether desaturation severity affects the immediate HRV.MethodsWe retrospectively analysed the electrocardiography signals in 5-min segments (n=39 132) recorded during clinical polysomnographies of 642 patients with suspected OSA. HRV parameters were calculated for each segment. The segments were pooled into severity groups based on the desaturation severity (i.e. the integrated area under the blood oxygen saturation curve) and the respiratory event rate within the segment. Covariate-adjusted regression analyses were performed to investigate possible confounding effects.ResultsWith increasing respiratory event rate, the normalised high-frequency band power (HFNU) decreased from 0.517 to 0.364 (p<0.01), the normalised low-frequency band power (LFNU) increased from 0.483 to 0.636 (p<0.01) and the mean RR interval decreased from 915 to 869 ms (p<0.01). Similarly, with increasing desaturation severity, the HFNU decreased from 0.499 to 0.364 (p<0.01), the LFNU increased from 0.501 to 0.636 (p<0.01) and the mean RR interval decreased from 952 to 854 ms (p<0.01). Desaturation severity-related findings were confirmed by considering the confounding factors in the regression analyses.ConclusionThe short-term HRV response differs based on the desaturation severity and the respiratory event rate in patients with suspected OSA. Therefore, a more detailed analysis of HRV and desaturation characteristics could enhance OSA severity estimation.

Association between antenatal glucocorticoid exposure and the activity of the stress system, cognition, and behavior in 8- to 9-year-old children: A prospective observational study.

Glucocorticoid (GC) -induced fetal programming of the activity of the hypothalamus-pituitary-adrenal axis (HPAA) and its associated cognitive and behavioral consequences in later life have been well characterized in several animal species. However, information on humans is scarce. In this study, we examined HPAA activity markers and associated outcomes at 8 to 9 years of age among children prenatally exposed to GC for suspected preterm birth. Our hypothesis was that antenatal exposure to the betamethasone (BM) is associated with exacerbation of HPAA activity in childhood. Prospective observational study in 31 children whose mothers received single (n=19) or multiple (n=12) courses of BM for threatened preterm birth but born with normal weight appropriate for the gestational age (median 37+6 weeks of gestation) compared with 38 non-exposed, age-matched children. Primary end point was the activity of the HPAA in response to the Trier Social Stress Test. Secondary end points were changes in autonomic nervous system (ANS) activity, cognitive performance (IQ), attention-deficit/hyperactivity disorder (ADHD) symptoms, and electrocortical activity (EEG). There was no statistically significant difference in HPAA activity markers between antenatal BM exposed and unexposed groups. ANS activity in BM-exposed children shifted towards a higher parasympathetic tone reflected by a higher overall high-frequency band power of heart rate variability. IQ scores were within normal limits for both groups; however, BM-exposed children had lower IQ scores than the unexposed group. BM-exposed group had marginally more ADHD core symptoms and increased electrocortical activity in the occipital brain region compared with controls. A monotonic dose-response relation between BM exposure and activity of the ANS and IQ was estimated in post-hoc analyses. Antenatal exposure to BM in the context of threatened preterm birth was not associated with changes in HPAA activity in childhood. However, BM exposure may be associated with changes in ANS activity. Antenatal GC prophylaxis is a valuable and often life-saving therapy, but its prescription may warrant a well-balanced risk-benefit assessment.

Comparison of Heart Rate Variability, QTc, and JT Interval Between Diabetic Patients and Healthy Controls: Role of Gender and Phases of Menstrual Cycle

Background and objectivesType 2 Diabetes mellitus (T2DM) is a heterogeneous group of metabolic disorders with variable degrees of insulin resistance and altered glucose metabolism. Increased attention in studying the role of gonadal hormones in diabetes is not only due to their relation to insulin sensitivity, and glucose tolerance but also to the gender-specific nature of the prevalence of various diabetic complications. The cyclical change in the hormone level in females will make it necessary to consider the menstrual cycle while analyzing the risk factors for diabetes. Hence, the role of gender and menstrual cycle in T2DM are analyzed here using the simple non-invasive cardiovascular risk indices like heart rate variability (HRV), QT interval corrected for heart rate (QTc), and JT interval.Materials and methodsIn this analytical study, T2DM patients in the age group of 18-45 years with less than five years duration from diagnosis and taking not more than two anti-hyperglycemic drugs were included. Time and frequency domains of HRV analysis, QTc, and JT intervals were compared with age and BMI matched control group. The comparison of these parameters was also made between two genders in the diabetic group and they were analyzed across different phases of the menstrual cycle in female diabetic patients when physiological variation in the gonadal hormones occurred as a natural phenomenon.ResultsHRV parameters were reduced and the QTc and JT intervals were prolonged in diabetic patients of both genders. Reduction in low-frequency (LF) band power and high-frequency (HF) band power of HRV analysis in diabetic females were statistically significant in the luteal phase of the menstrual cycle in comparison with age and BMI-matched healthy controls. There was no significant difference in the HRV parameters, QTc, and JT interval between the male and female diabetic groups. HF band power is significantly reduced in the menstrual phase and relatively higher in the follicular phase when compared to the luteal phase among female diabetic patients.ConclusionThe reduced sympathetic and parasympathetic activity were observed in diabetic patients of both genders and they were significant in the luteal phase of diabetic females compared to the healthy control group. Vagal activity is relatively higher in the follicular phase of the menstrual cycle in female diabetic patients.

Effects of Supplemental Oxygen on Cardiovascular and Respiratory Interactions by Extended Partial Directed Coherence in Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic and restrictive disease characterized by fibrosis and inflammatory changes in lung tissue producing a reduction in diffusion capacity and leading to exertional chronic arterial hypoxemia and dyspnea. Furthermore, clinically, supplemental oxygen (SupplO2) has been prescribed to IPF patients to improve symptoms. However, the evidence about the benefits or disadvantages of oxygen supplementation is not conclusive. In addition, the impact of SupplO2 on the autonomic nervous system (ANS) regulation in respiratory diseases needs to be evaluated. In this study the interactions between cardiovascular and respiratory systems in IPF patients, during ambient air (AA) and SupplO2 breathing, are compared to those from a matched healthy group. Interactions were estimated by time series of successive beat-to-beat intervals (BBI), respiratory amplitude (RESP) at BBI onset, arterial systolic (SYS) and diastolic (DIA) blood pressures. The paper explores the Granger causality (GC) between systems in the frequency domain by the extended partial directed coherence (ePDC), considering instantaneous effects. Also, traditional linear and nonlinear markers as power in low (LF) and high frequency (HF) bands, symbolic dynamic indices as well as arterial baroreflex, were calculated. The results showed that for IPF during AA phase: 1) mean BBI and power of BBI-HF band, as well as mean respiratory frequency were significantly lower (p < 0.05) and higher (p < 0.001), respectively, indicating a strong sympathetic influence, and 2) the RESP SYS interaction was characterized by Mayer waves and diminished RESP BBI, i.e., decreased respiratory sinus arrhythmia. In contrast, during short-term SupplO2 phase: 1) oxygen might produce a negative influence on the systolic blood pressure variability, 2) the arterial baroreflex reduced significantly (p < 0.01) and 3) reduction of RSA reflected by RESP BBI with simultaneous increase of Traube-Hering waves in RESP SYS (p < 0.001), reflected increased sympathetic modulation to the vessels. The results gathered in this study may be helpful in the management of the administration of SupplO2.

The Effect of Unilateral Nephrectomy on Arterial Blood Pressure Variability in Spontaneously Hypertensive Rats

&#x0D; &#x0D; &#x0D; The aim of the current study was to investigate the effects of unilateral nephrectomy (ULN) on fast oscillation of arterial blood pressure in spontaneously hypertensive rats (SHR). Experiments were carried out on conscious normotensive Wistar rats and SHR divided in groups with intact kidneys: W, n = 10; SHR, n = 9 and with unilateral nephrectomy: WN, n = 10; SHRN, n = 10. ULN was performed under general anaesthesia (Nembutal 35 mg/kg b.w. i.p.), eight days before the experiments. Blood pressure variability was investigated by means of spectral analysis of systolic (SAP) diastolic (DAP) and mean (MAP) arterial blood pressure, estimated in directly registered arterial blood pressure wave. In SAP, DAP and MAP spectrograms, derived by Lab View software equipment, the spectral power (P) in low (LF, 20–195 mHz), mid (MF, 195–605 mHz) and high frequency (HF, 605—3000 mHz) bands was calculated. PLF in SAP spectrograms increased after ULN both in Wistar rats and SHR. ULN led to decrease of PMF in SAP, DAP and MAP spectrograms only in SHR. The ULN provokes changes in blood pressure variability in different manner in the normotensive and the spontaneously hypertensive rats. In addition to humorally-mediated low-frequency oscillations, ULN in SHR also af- fected the spectral characteristics of the arterial pressure in which sympathetic nervous activity operates.&#x0D; &#x0D; &#x0D;

Heart rate variability is markedly abnormal following surgical repair of atrial and ventricular septal defects in pediatric patients

BackgroundAbnormalities in heart rate variability (HRV) have been associated with increased morbidity and mortality. Adults with a history of successful correction of atrial septal defects (ASDs) and ventricular septal defects (VSDs) have clinically relevant abnormalities in HRV. The etiology of these abnormalities is unknown as is when they occur in the natural history of these lesions. We sought to determine whether the abnormalities described in adult patients are identifiable in pediatric patients. Materials and methodsEighty-five ASD patients, 105 VSD patients, and 142 non-cardiac surgical comparison patients aged 0–18 years were studied during post-operative admission to the critical care unit using continuously monitored bedside electrocardiographic (ECG) data. ResultsASD and VSD patients had statistically significantly lower time-domain heart rate variability parameters, i.e., standard deviation of NN interval duration, and lower frequency-domain heart rate variability parameters, i.e., power in the high frequency band and power in the low frequency band, compared to the comparison cohort. The lower frequency band to high frequency band power ratio was lower in ASD patients and higher in VSD patients compared to the comparison cohort. The abnormalities identified correlate well with patterns described in adult patients. ConclusionPost-surgical ASD and VSD patients have markedly abnormal heart rate variability patterns indicative of reduced parasympathetic activity and predominance of sympathetic activity. The HRV abnormalities described in adult patients are identifiable as early as the postoperative period in childhood. This finding warrants prospective study to identify drivers of this phenomenon.

20.5 Preliminary Evidence for Associations of the Infant Gut Colonization With Parent-Infant Relationship, Maternal Depression, Stress, and Parenting Styles

The objectives of this presentation are to: 1) examine associations among infant gut colonization based on microbiome measurements in the infant population and maternal depressive symptoms and distress; 2) examine associations among infant microbiome and parent-infant interactions during a vaccination procedure; and 3) examine how infant cries correlate with their microbiome at 4 months of age. For this pilot study, we recruited a prospective cohort of infants (n = 31) and parents (n = 31). We examined the association between the infant gut microbiome at 4 months during well-child visits (WCVs), maternal depression (by Patient Health Questionnaire-9 [PHQ-9]), parent and child characteristics and life stress (by Parenting Stress Index [PSI-IV]), and parent-infant interactions (by Measure of Adult and Infant Soothing and Distress [MAISD]). For each of the variables, we looked at 3 types of associations to identify the component of the microbiome revealed by whole-genome shotgun sequencing: β-diversity (via Bray-Curtis [BC] and Jaccard distances), α-diversity (via Shannon and Inverse-Simpson indexes), and differential abundance (via linear models for differential abundance [LinDA]). Infant cries in response to vaccination were assessed for spectral characteristics, with higher frequencies being associated with greater stress response (mid frequency: 1000-5000 Hz, high frequency: 5000 Hz+). Taxonomic classification identified 19 phyla, 417 genera, and 1246 species. The PHQ-9 scores obtained at 2 months were associated with 4 bacterial species (Ruminococcus flavefaciens, Actinomyces johnsonii, [Clostridium] dakarense, and Bilophila wadsworthia; false discovery rate [FDR] < 0.1) and β-diversity (p = 0.006-BC; p = 0.005-Jaccard). Infant cries with greater high-frequency band power (p < 0.03) and a greater high-to-mid frequency ratio metrics (p < 0.05) associated with higher infant stress were related to lower α-diversity. There were no correlations between PHQ-9 at 4 months, PSI-IV, and microbiome diversity. Data from our study point to a connection between higher perception of stress in infants reflected in their cries and lower microbiome diversity (higher diversity more desirable). We found that parental depressive symptoms influenced their infants’ microbiome. More studies are needed to explore ways in which the quality of the infant-caregiver relationship influences intestinal microbiota.

Spectral decomposition of heart rate variability using generalized harmonic analysis

In this paper, a method for decomposing harmonics in the spectrum of heart rate variability (HRV) using generalized harmonic analysis (GHA) is introduced. First, a simulated RR interval signal generated by an integral pulse frequency modulation model was decomposed spectra by GHA, Pisarenko harmonic decomposition (PHD), and autoregressive (AR) spectral decomposition model. The spectral profiles were obtained by the GHA, PHD, and AR methods for various numbers of extracted sinusoids and model orders from 1 to 48. The spectral profiles of GHA were the most stable. Of the power values of the sinusoids extracted by each method, it was clear that the power values estimated by GHA were approximately equal to the mean square value and closer than that obtained using the PHD or a fast Fourier transform (FFT). Second, a comparison of the power of the low-frequency (LF) and high-frequency (HF) band components reveals that the values obtained by GHA are similar to those obtained by FFT for the analysis using a real ECG signal. Third, Bland-Altman analysis reveals that LF and HF band power value calculated by the GHA are compatible with ones by the Lomb-Scargle periodogram using MIT-BIH normal sinus rhythm database from short term recordings of 30 min. These results suggest that GHA is a useful tool for calculating the power of a component in the spectral analysis of HRV. The limitations of spectral decomposition by GHA are still discussed.

FMRI and intra-cranial electrocorticography recordings in the same human subjects reveals negative BOLD signal coupled with silenced neuronal activity

Positive blood oxygenation level-dependent (BOLD) responses (PBR), as measured by functional Magnetic Resonance Imaging (fMRI), are the most utilized measurements to non-invasively map activity in the brain. Recent studies have consistently shown that BOLD responses are not exclusively positive. Negative BOLD responses (NBR) have been reported in response to specific sensory stimulations and tasks. However, the exact relationship between NBR and the underlying metabolic and neuronal demand is still under debate. In this study, we investigated the neurophysiological basis of negative BOLD using fMRI and intra-cranial electrophysiology (electrocorticography, ECoG) measurements from the same human participants. We show that, for those electrodes that responded to visual stimulation, PBR are correlated with high-frequency band (HFB) responses. Crucially, NBR were associated with an absence of HFB power responses and an unpredicted decrease in the alpha power responses.