Frequency Domain Parameters Research Articles

Peripheral blood flow estimated by laser doppler flowmetry provides additional information about sleep state beyond that provided by pulse rate variability.

Pulse rate variability (PRV), derived from Laser Doppler flowmetry (LDF) or photoplethysmography, has recently become widely used for sleep state assessment, although it cannot identify all the sleep stages. Peripheral blood flow (BF), also estimated by LDF, may be modulated by sleep stages; however, few studies have explored its potential for assessing sleep state. Thus, we aimed to investigate whether peripheral BF could provide information about sleep stages, and thus improve sleep state assessment. We performed electrocardiography and simultaneously recorded BF signals by LDF from the right-index finger and ear concha of 45 healthy participants (13 women; mean age, 22.5 ± 3.4years) during one night of polysomnographic recording. Time- and frequency-domain parameters of peripheral BF, and time-domain, frequency-domain, and non-linear indices of PRV and heart rate variability (HRV) were calculated. Finger-BF parameters in the time and frequency domains provided information about different sleep stages, some of which (such as the difference between N1 and rapid eye movement sleep) were not revealed by finger-PRV. In addition, finger-PRV patterns and HRV patterns were similar for most parameters. Further, both finger- and ear-BF results showed 0.2-0.3Hz oscillations that varied with sleep stages, with a significant increase in N3, suggesting a modulation of respiration within this frequency band. These results showed that peripheral BF could provide information for different sleep stages, some of which was complementary to the information provided by PRV. Furthermore, the combination of peripheral BF and PRV may be more advantageous than HRV alone in assessing sleep states and related autonomic nervous activity.

Association of Autonomic Balance With Phone Call Duration in Healthy Individuals.

Background This study aimed to estimate the association of autonomic balance with the duration of phone calls in healthy individuals. Methodology A total of 30 subjects aged between 18 and 30 years without any established systemic disease and using mobile phones for more than five years with minimum daily usage of 30 minutes were included in this analytical study. Heart rate variability (HRV) was recorded using a three-channel physiograph (AD Instruments South Asia (India) Pvt. Ltd., New Delhi, India) with the software LabChart PROV8.1.8 with HRV Module version 2.0.3 for 10 minutes. Time domain parameters were recorded in terms of the standard deviation of normal to normal interval (SDNN), root mean square of successive differencesbetween normal heartbeats (RMSSD), R-R intervals greater than 50 ms (pRR50), and mean heart rate (MHR), and frequency domain parameters were total power,low-frequency power (LF), high-frequency power (HF), and the ratio of low-frequency to high-frequency power (LF/HF). HRV was recorded three times in each subject that included baseline HRV, HRV during the use of a mobile phone, and HRV after the use of a mobile phone. Results A total of 30 subjects (14 males and 16 females) participated in this study. The mean age of participants was 31.93 ± 8.59 years (32.07 ± 9.87 years for males, and 31.81 ± 7.64 years for females). There were no findings of significant arrhythmiain any of the participants. There was a significant difference in pRR50 on comparing all three phases (p = 0.036). However, there was no significant variation in other parameters such as very low frequency (VLF, ms2), VLF (%), LF (ms2), LF (%), HF (ms2), HF (%), LF/HF, SDNN (ms), RMSSD (ms), Poincare plot standard deviation perpendicular to the line of identity (ms), Poincare plot standard deviation along the line of identity (ms), systolic blood pressure (mmHg), and diabolic blood pressure (mmHg) during, before, and after exposure to mobile phone calls. There was no significant difference in the value of all parameters between males and females (p < 0.05). Conclusions Mobile phone calls may influence HRV and autonomic balance. This change may be affected by the electromagnetic field and by speaking as well.

Effects of training on the heart rate variability of competitive soccer players: A systematic review with meta-analysis

Heart rate variability (HRV) has become a popular method for monitoring readiness, recovery, and other training-derived parameters to optimize physical performance. This systematic review aimed to examine the impact of training interventions on HRV fluctuations in competitive soccer players. The EBSCO, Web of Sciences (WOS), and Cochrane databases were used for the search. After identifying 293 studies, 13 were included in a qualitative analysis and 6 in a quantitative analysis. Training had a small and nonsignificant effect on HRV in competitive soccer players (Effect Size (ES) = 0.143, Standard Error (SE) = .108, p = .186, 95% confidence interval (CI) [−0.69, 0.355]). Soccer-focused training resulted in higher HRV scores than combined training (Q(2) = 38.13, p = .05). Higher ES were found for frequency domain parameters ( p = .047; d = 0.059), night assessment ( p = .016; d = 0.453), and soccer-focused training ( p = .006; d = 0.366). HRV was also found to have a greater impact on females ( p = .027; d = 0.275) and/or professional soccer players ( p = .007; d = 0.302). Soccer training had a minimal and nonsignificant effect on HRV.

Evaluation of frequency domain parameters of heart rate variability in patients with essential hypertension

Background: The autonomic nervous system (ANS) is crucial for controlling blood pressure and preventing the onset of hypertension. Analyzing heart rate variability (HRV) is a common diagnostic method for evaluating the actions of the ANS. The two domains under which HRV can be evaluated are the time domain method and the frequency domain approach. Aim and Objective: The primary objective of this study was to check the cardiovascular health and cardiac autonomic regulation of patients with essential hypertension by assessing frequency domain parameters of HRV. Materials and Methods: The study included 50 patients with essential hypertension in the age group of 35–55 years and 50 healthy individuals of the same age group were selected as controls. HRV assessment was done using standardized instruments and emWave Pro software. All the individuals went through 5 min HRV assessment in the supine position. The frequency domain parameters were checked for analysis of HRV. Results: Very low frequency, low frequency (LF), and high frequency (HF) were significantly lower in hypertensive patients as compared to healthy individuals. The mean value of the LF/HF ratio (2.01 ± 0.61) in hypertensive patients was significantly higher as compared to normal individuals (0.99 ± 0.17, P &lt; 0.001). Total power was also significantly low in hypertensive individuals (457.40 ± 133.63 ms2) than healthy individuals (457.40 ± 133.63 ms2, P &lt; 0.001). Conclusion: The study indicates that as compared to healthy individuals, in hypertensive patients low total power and high LF/HF ratio are seen which are suggestive of poor cardiovascular health and cardiac autonomic dysregulation in hypertensive individuals.

Heart Rate Variability among Healthy Untrained Adults during Mild Intensity Stationary Cycling Exercise.

Stationary cycling is the popular, preferred, and convenient form of exercise. During exercise, autonomic modulation is seen which can be assessed by heart rate variability (HRV). The aim of the study was to evaluate the changes in HRV during mild-intensity cycling exercise. An observational cross-sectional study was done on 20 healthy male volunteers with the age (35.44 ± 4.12), height (71.12 ± 11.98), and weight (161.23 ± 11.65), BMI (27.12 ± 3.49) attending various YOGA sessions in AYUSH OPD. Volunteers underwent an exercise program at the mild intensity of 30% to 50% of maximal heart rate on a stationary cycle for 20 min. HRV was recorded by the HRV mobile unit Dynamika Machine at rest, every 5 min (4×) over 20 min and during the recovery period. Repeated measures of analysis of variance with post-hoc analysis with Bonferroni and Holm's multiple comparisons. Significant change was observed in mean heart rate and time domain parameters. Frequency domain parameters that showed significant change were total power, High Frequency- HF (ms2), Very Low Frequency -VLF (ms2), Low Frequency -LF (ms2), and Very Low Frequency %-VLF (%). The HRV parameters conclusively point towards cardiac parasympathetic withdrawal and sympathetic dominance at the initiation of exercise. With the progression of exercise, the sympathetic influence is retained. In the recovery period parasympathetic reactivation gains control over heart rate as well as HRV. The HRV response to exercise challenges may be helpful in designing exercise programs based on variations in the autonomic response.

Correlation between heart rate variability and cerebral autoregulation in septic patients.

Heart rate variability (HRV) may provide an estimation of the autonomous nervous system (ANS) integrity in critically ill patients. Disturbances of cerebral autoregulation (CAR) may share common pathways of ANS dysfunction. To explore whether changes in HRV and CAR index correlate in critically ill septic patients. Prospectively collected data on septic adult (> 18years) patients admitted into a mixed Intensive Care between February 2016 and August 2019 with a recorded transcranial doppler CAR assessment. CAR was assessed calculating the Pearson's correlation coefficient (i.e. mean flow index, Mxa) between the left middle cerebral artery flow velocity (FV), insonated with a 2-MHz probe, and invasive blood pressure (BP) signal, both recorded simultaneously through a Doppler Box (DWL, Germany). MATLAB software was used for CAR assessment using a validated script; a Mxa >0.3 was considered as impaired CAR. HRV was assessed during the same time period using a specific software (Kubios HRV 3.2.0) and analyzed in both time-domain and frequency domain methods. Correlation between HRV-derived variables and Mxa were assessed using the Spearman's coefficient. A total of 141 septic patients was studied; median Mxa was 0.35 [0.13-0.60], with 77 (54.6%) patients having an impaired CAR. Mxa had a significant although weak correlation with HRV time domain (SDNN, r=0.17, p=0.04; RMSSD, r=0.18, p=0.03; NN50, r=0.23, p=0.006; pNN50, r=0.23, p=0.007), frequency domain (FFT-HF, r=0.21; p=0.01; AR-HF, r=0.19; p=0.02), and non-linear domain (SD1, r=0.18, p=0.03) parameters. Impaired CAR patients had also all of these HRV-derived parameters higher than those with intact CAR. In this exploratory study, a potential association of ANS dysfunction and impaired CAR during sepsis was observed.

Effectiveness of frequency domain parameters in decision tree-based classification of GMAW defects

Effectiveness of frequency domain parameters in decision tree-based classification of GMAW defects

Sleep Deprivation and Heart Rate Variability in Healthy Volunteers: Effects of REM and SWS Sleep Deprivation.

Using PSG-guided acute selective REM/SWS sleep deprivation in volunteers, this study examined the effects of sleep deprivation on the cardiovascular and autonomic nervous systems, as well as the relationship between cardiac neuromodulation homeostasis and cardiovascular disease. An experiment was conducted using 30 healthy volunteers (male : female = 1 : 1, aged 26.33 ± 4.5 years) divided into groups for sleep deprivation of SWS and REM sleep, and then, each group was crossed over for normal sleep (2 days) and repeated sleep deprivation (1 day, 3 times). During the study period, PSG and ELECTRO ECG monitoring were conducted, and five-minute frequency domain parameters and blood pressure values were measured before and after sleep deprivation. Changes in VLF, LFnu, LF/HF, HF, and HFnu after SWS sleep deprivation were statistically significant (P < 0.05), but not LF (P = 0.063). Changes in VLF, LF, HF, LF/HF, LFnu, and HFnu after REM sleep deprivation were not statistically significant (P > 0.05). An increase in sympathetic nerve activity results from sleep deprivation and sudden awakening from SWS sleep is associated with a greater risk of cardiovascular disease.

Cardiovascular autonomic responses in reproductive and post-menopausal women

Background: Autonomic responses are a sensitive indicator for assessing balance in sympatho-vagal system. Many studies have shown an increased response in the sympathetic system in post-menopausal women. Alteration in autonomic nerve function causes an increased incidence of hypertension, arrhythmias, or acute coronary syndrome. Thus, this study aims to find out the heart rate variability (HRV) among reproductive and post-menopausal women. Aims and Objectives: The aim of the study was to compare the cardiovascular autonomic responses among reproductive and post-menopausal women. Materials and Methods: This cross-sectional study was conducted in the department of physiology at government medical college, Kottayam on 40 reproductive and 40 post-menopausal women. Using PHYSIOPAC-PP4 (Medicaid Systems Chandigarh) machine, an electrocardiogram was recorded in both groups in the supine position for 5 min. The frequency and time domain data obtained were analyzed using SPSS software. Results: The mean age group in reproductive women was 43 and post-menopausal women was 54. In the power spectrum analysis of HRV parameters the mean value of frequency domain Low frequency (LF) in reproductive women was 72.05 (S.D = 5.706) and post-menopausal women was 79.48 (S.D = 3.789). The high frequency (HF) in reproductive women was 28 (S.D = 5.588) and post-menopausal women were 20.53 (S.D = 3.789). The LF/HF ratio mean value obtained in reproductive women was 2.723 (S. D = 0.759) and post–menopausal was 3.992 (S.D 0.785). In the various time domain parameters, we estimated the mean value of the root mean square of successive differences (RMSSD) between normal heartbeats RMSSD and obtained the value in reproductive women as 25.05 (S.D = 11.88) and post-menopausal women as 12.68 (S.D = 5.535). The RR interval triangular index mean value in reproductive women was 0.0520 (S.D = 0.013) and post-menopausal women were 0.0345 (S.D = 0.01). In all these parameters, the P-value was found to be &lt;0.001, so statistically highly significant. Conclusion: In this study, higher values in time domain and frequency domain parameters for assessing sympathetic functions were seen in postmenopausal women when compared to women of the reproductive age group which was statistically significant. This may be due to age and hormonal influences. The power spectrum analysis of HRV parameters was proved to be a noninvasive method to assess the sympathovagal balance in the study group of women.

Effect of Surya Namaskar on Autonomic Status and Serum Cortisol Levels in Male Medical Students: A Longitudinal Study

Introduction: Stress is an unavoidable and ongoing phenomenon in human life that affects physiological processes in the body. Regular practice of Surya Namaskar, a yogic exercise, has been shown to improve autonomic functions by reducing sympathetic activity, thereby decreasing stress levels and improving cortisol levels. Aim: To evaluate the effects of Surya Namaskar on autonomic status and serum cortisol levels among medical students. in the Department of Physiology at the Faculty of Medicine and Health Sciences, SGT University, Gurugram, Haryana, India. The study duration was three months, from November 2021 to January 2022. A total of 30 male medical students, aged between 18 and 21 years, were included in the study. Blood samples for cortisol estimation were collected before the start of the study and after six weeks of regular yogic practice. Parameters such as mean pulse rate, Blood Pressure (BP), and Low Frequency to High Frequency (LF/HF) ratio were also studied during these two time points. Statistical analysis of Heart Rate Variability (HRV) parameters, including Standard deviation of the N-N interval (SDNN), mean Heart Rate (HR), and pNN50, was performed using Analysis of Variance (ANOVA) at baseline and after six weeks. Comparison of serum cortisol levels within the groups was done using paired t-tests. Results: The mean age of the study participants was 20.37 years. Comparison of HRV frequency domain parameters (LF, HF, and LF/HF ratio) at baseline, day one, and after six weeks of yogic practice showed statistically significant variations in LF/ HF ratio after six weeks (p-value=0.001). Baseline serum cortisol levels compared to levels after six weeks of yogic practice were also found to be statistically significant (p&lt;0.001). Conclusion: There is a positive association between cortisol levels and autonomic parameters, as evidenced by the results of the autonomic battery of tests. Incorporating yogic interventions into one’s lifestyle helps reduce sympathetic parameters and shift the balance towards parasympathetic dominance.

Effectiveness of Frequency Domain Parameters in Decision Tree Based Classification of GMAW Defects

Effectiveness of Frequency Domain Parameters in Decision Tree Based Classification of GMAW Defects

Changes in Autonomic Nervous System Function in Patients &gt;60 Years of Age with Coronary Heart Disease, and Normotension or Hypertension: An Observational Study

Aim: The aim of this observational study was to perform in-depth analysis of autonomic nervous system function in patients older than 60 years of age with coronary artery disease, and normotension or hypertension. Method: A total of 104 patients older than 60 years with coronary heart disease (CHD) were divided into a normotension group and hypertension (HT) group, and 24-hour Holter monitoring was performed to assess autonomic function. Result: Among the 104 patients with CHD analyzed, 52 had normotension, and 52 had hypertension. The 24-hour Holter results based on time-domain methods indicated that the values of the time-domain parameters of heart rate variability were significantly lower in the CHD+HT group than the CHD group. Furthermore, during both the daytime and nighttime, the time-domain parameters were significantly lower in the CHD+HT group than the CHD group. No difference was observed in autonomic function during the daytime and nighttime in each group. Values of frequency-domain parameters of heart rate variability were also significantly lower in the CHD+HT group than the CHD group. More patients in the CHD+HT group than the CHD group received percutaneous coronary intervention (57.69% vs. 50% χ2=0.619, P=0.55). In 12 months of follow-up, we found no significant differences in rehospitalization for unstable angina and target lesion revascularization between patients with CHD with normotension versus hypertension. Conclusion: The heart autonomic nervous system dysfunction in patients older than 60 years with CHD with hypertension was more severe than that in patients with CHD with normotension, and therefore, should receive greater clinical attention.

AN EXPLORATORY STUDY OF PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS TO IDENTIFY SIMPLE, ROBUST AND RELEVANT BIOMARKERS FOR THERAPEUTIC INTERVENTIONS FOR PTSD: STUDY RATIONALE, KEY ELEMENTS OF DESIGN AND A CONTEXT OF WAR IN UKRAINE

Introduction. The incidence of post-traumatic stress disorder (PTSD) is increasing due to war in Ukraine is of growing importance as this disorder is a serious risk factor for alcohol/drug abuse, depression, suicide and functional dysregulation of internal organs, in particular cardiovascular, endocrine, immune systems. PTSD can also lead to social inadaptation in family and at work. This makes PTSD a very important social problem in Ukraine that causes significant economic damage, since most of the PTSD patients are young and in working age.&#x0D; Objectives. The purpose of this paper is to describe the rationale, key elements of design, methodology and future prospects of the ongoing project “Exploratory study of health related physiological and biochemical parameters to identify simple, robust and relevant biomarkers for therapeutic interventions for PTSD patients”.&#x0D; Methods. Short time ECG records (5 minutes in supine position and 6 minutes in orthostatic test) recorded by “CARDIOLAB” (Kharkiv, Ukraine) digital ECG device with software to analyze HRV was used to calculate time-domain and frequency-domain parameters of HRV.&#x0D; Results. The pattern of HRV changes indicates suppression of parasympathetic activity, low overall spectral power and dominance of sympathetic branch of autonomic nervous system in participants with PTSD.&#x0D; Conclusions. PTSD has no effective treatment so far and the best clinical practices rarely reach efficacy of 50%. The realization of the exploratory clinical study described in this paper will provide insights in the mechanisms underlying systemic consequences of PTSD and will build the evidence enabling clinical trial(s) for studying treatment intervention for patients with PTSD.

Video-Based Behaviorally Coded Movement Assessment for Adolescents with Intellectual Disabilities: Application in Leg Dribbling Performance

Measuring motor performance in individuals with intellectual disabilities (ID) is quite challenging. The objective of this study was to compare the motor performances of individuals with ID and those with typical development (TD) during soccer dribbling through video-based behavior-coded movement assessment along with a wearable sensor. A cross-sectional research design was adopted. Adolescents with TD (N = 25) and ID (N = 29) participated in the straight-line and zigzag soccer dribbling tests. The dribbling performance was videotaped, and the footage was then analyzed with customized behavior-coding software. The coded parameters were the time for movement completion, the number of kicks, blocks, steps, the number of times the ball went out of bounds, the number of missed cones, and the trunk tilt angle. Participants with ID exhibited significantly poorer performance and demonstrated greater variances in many time and frequency domain parameters. It also revealed that participants with ID kicked with both feet while dribbling, whereas those with TD mainly used the dominant foot. The present findings demonstrated how the ID population differed from their peers in lower-extremity strategic control. The customized video-based behavior-coded approach provides an efficient and effective way to gather behavioral data and calculate performance parameter statistics in populations with intellectual disabilities.

Cutoff Point of Mini-Balance Evaluation Systems Test Scores for Elderly Estimated by Center of Pressure Measurements by Linear Regression and Decision Tree Classification.

Understanding balance ability and assessing the risk of possible falls are very important for elderly rehabilitation. The Mini-Balanced Evaluation System Test (Mini-BESTest) is an important survey for older adults to evaluate subject balance, but it is not easy to complete due to various limitations of physical activities, including occasional fear of injury. A center of pressure (CoP) signal can be extracted from a force pressure plate with a short recording time, and it is relatively achievable to ask subjects to stand on a force pressure plate in a clinical environment. The goal of this study is to estimate the cutoff score of Mini-BESTest scores from CoP data. CoP signals from a human balance evaluation database with data from 75 people were used. Time domain, frequency domain, and nonlinear domain parameters of 60 s CoP signals were extracted to classify different cutoff point scores for both linear regression and a decision tree algorithm. Classification performances were evaluated by accuracy and area under a receiver operating characteristic curve. The correlation coefficient between real and estimated Mini-BESTest scores by linear regression is 0.16. Instead of linear regression, binary classification accuracy above or below a cutoff point score was developed to examine the CoP classification performance for Mini-BESTest scores. The decision tree algorithm is superior to regression analysis among scores from 16 to 20. The highest area under the curve is 0.76 at a cutoff point score of 21 for the CoP measurement condition of eyes opened on the foam, and the corresponding classification accuracy is 76.15%. CoP measurement is a potential tool to estimate corresponding balance and fall survey scores for elderly rehabilitation and is useful for clinical users.

872 ENDOTHELIAL AND CARDIAC AUTONOMIC FUNCTION IN PATIENTS WITH A RECENT SARS-COV-2 INFECTION

Abstract Background A significant proportion of patients recovering from SARS-CoV-2 infection (Covid-19) complain a wide variety of bothersome symptoms, including symptoms potentially related to cardiac involvement, that may significantly impair their quality of life (post-Covid or long-Covid syndrome). However, full diagnostic investigation usually does not reveal significant structural or functional cardiac abnormalities. Whether cardiac autonomic dysfunction and/or endothelial dysfunction may play a role in post-COVID-19 symptoms, however, has poorly been investigated. Methods We prospectively enrolled 63 young adult patients (age 18-55 years) without any previous cardiovascular disease, referred to our “Post-COVID-19” Day Hospital ward for a clinical follow-up after 3 months from SARS-CoV-2 infection. In all patients endothelium-dependent vasodilator function was assessed non-invasively by measuring the change of brachial artery diameter in response to hyperaemia after 5 minutes of forearm ischemia (flow-mediated dilatation, FMD); furthermore, endothelium-independent vasodilator function was assessed by measuring the change of brachial artery diameter in response to sublingual nitro-glycerine (25 µg) (nitrate-mediated dilatation, NMD). A 24-hour ECG Holter monitoring (HM) was performed to assess cardiac autonomic function by obtaining time-domain and frequency-domain parameters of heart rate variability (HRV). Results Symptoms of potential cardiac origin (dyspnoea on exertion, chest pain, arrhythmic symptoms) were referred by 47 patients (74.6%, Group 1), whereas 16 (25.4%, Group 2) were free from any possible cardiac symptom. The two groups did not differ in age, sex and cardiovascular risk factors. FMD was 7.29±3.4% and 7.01±2.3% in Group 1 and 2, respectively (p=0.77), whereas NMD was 11.1±3.8% and 14.2±4.9 in the two groups, respectively (p=0.013). No significant differences were observed for HRV parameters between the two groups (see Table). Conclusions Our data do not support a role for both endothelial dysfunction and cardiac autonomic dysfunction in the persistence of symptoms of potential cardiac origin in patients with a recent SARS-CoV-2 infection. The lower endothelium-independent arterial vasodilator found in these patients, however, deserves further investigation.

Multistate fault diagnosis strategy for bearings based on an improved convolutional sparse coding with priori periodic filter group

Bearings are a critical component of rotating machines; when they fail, critical equipment becomes unavailable, damage may occur beyond the bearing itself, and safety concerns arise. Determining that a bearing structure is compromised before catastrophic failure permits the protection of plant, people, and productivity. When bearings malfunction, the features of single and multiple faults are masked and accompanied by noise and other signal degrading artifacts affecting the signals from the vibrational sensors. In these circumstances, detection and diagnosis of multistate bearing faults is difficult. To overcome these challenges, an improved convolutional sparse coding (ICSC) model, based on a priori periodic filter groups (PPFG), is proposed to respond to the multistate fault problems of bearings. A Laplace wavelet is constructed with one-sided decay related to the vibration pattern of the signal. The best-matched wavelet is optimally determined by correlation analysis of the signal frequency domain parameters and the time domain damping parameters. The best-matched wavelet and the kurtosis criterion are used to construct a PPFG based on the theoretical period of the fault. The ICSC based on the PPFG obtains mapping coefficients characterizing different vibrational features of the signal. The envelope spectrum analysis of the various mapping coefficients identifies and confirms the fault-revealing components in the multistate signal. The ICSC results have a relatively good sparse time domain, and the fault-identifying features in the envelope spectrum are enhanced. Multiple faults can be easily identified. The effectiveness and robustness of the PPFG/ICSC are demonstrated through a complete experimental analysis of simulated, single-fault, and multifault signals, as well as a comparative analysis of the previous methods – Fast SK, CBPDN, and VMD-ICA – which verifies that the PPFG/ICSC is more robust, accurate, and efficient than the previous methods.

Maternal Weight Gain during Pregnancy and the Developing Autonomic Nervous System—Possible Impact of GDM

The intrauterine environment is known to affect the offspring's long-term risk for obesity and diabetes. Previous data show that maternal metabolism and gestational weight gain (GWG) are associated with fetal autonomic nervous system (ANS) function, which can be assessed with heart rate variability (HRV). We investigated whether this association is also present in 2-year-old children and addressed the impact of gestational diabetes (GDM). We examined the 2-year-old offspring of mothers who had undergone a 5-point, 75 g oral glucose tolerance test during pregnancy. To assess HRV, a 10-minute ECG was recorded, and time domain and frequency domain parameters were analyzed. Body composition was assessed using bioelectrical impedance testing. We examined 67 children (33 girls, 34 boys), 30 of whom were born to mothers with treated GDM and normoglycemic pregnancies (NGT), respectively. No differences were found between the groups with regard to birth weight, weight at the age of 2 years, and body fat content. We observed that GWG was associated with heart rate and HRV, indicating that children of mothers with low GWG had a lower parasympathetic tone. This association was detected in NGT-exposed-but not in GDM-exposed-children. HR and HRV correlated with body fat and fat-free mass in children from normoglycemic pregnancies only. We found that the impact of maternal GWG on offspring ANS function was missing in the presence of treated GDM. The balance of the ANS was related to offspring body composition in children from NGT pregnancies only. Our results suggest that maternal weight gain during pregnancy has a critical impact on the developing ANS, which might be disturbed in the presence of GDM.

Semi-occluded Nasal Tract Exercises (SONTEs): Nasal Tube in Water Exercises Using Nasal Consonants

This study analyzes the effects of the vocal exercises called semi-occluded nasal tract exercises (SONTEs), which were carried out with a new appliance that extends the nasal cavity as a part of the vocal tract. The acoustic, aerodynamic and electroglottographic (EGG) measurements were compared with those of the traditional semi-occluded vocal tract exercises (SOVTEs) of phonation in water. In this study, 34 women were randomly asked to perform phonation in water for 5 min through the nasal and oral routes with the sounds /m/ and /ɔ/, respectively, using a tube with a submersion depth of 5 cm. The acoustic, aerodynamic and EGG measurements before and after the exercises were analyzed using the appropriate statistical methods. No significant difference was found in the time and frequency domain parameters before and after the exercises, except for the amplitude perturbation quotient (APQ) values, which decreased after both exercises. In addition, there was no significant difference in any aerodynamic parameters before and after the exercises, but the mean SPL values significantly increased after both exercises. The oral and nasal peak inspiratory flow rates increased after both exercises, but the increase peaked after the SONTEs implementation. As expected, the EGG-jitter and EGG-periodicity values had a reciprocal interaction with each other, while differences were observed between the values of the vocal fold movements measured in both exercises. SONTEs may be as effective as the conventional SOVTEs because it made tube phonation into water possible through artificial extension of the nasal cavity and increased the resonant effect by using the positive effects based on the principles of SOVTEs.

Heart rate variability in student pilots during the flight training: a preliminary report

Heart rate (HR) indicates the number of beats per minute (bpm) of the heart, while heart rate variability (HRV) indicates the temporal fluctuation of the intervals between adjacent beats (NN). HRV expresses neuro-cardiac activity and is generated by heart-brain interactions and dynamics related to the function of the Autonomous Nervous System (ANS) and other components (body and ambient temperature, respiration, hormones, blood pressure). The flight activity, especially during training, provides for a prolonged state of alert of the student pilot, as well as careful management of the flight and simultaneous planning of the next steps, with attention to the unusual conditions and emergencies that may occur during all various stages. HRV can provide a good reference index for estimating the degree of evolution of the training process of student pilots and a valid tool for some indications of a physiological as well as clinical nature. To investigate this issue, we started a series of experiments, still ongoing, by coupling the flight task times of student pilots with changes in their HRV. Before each experimental session, the participating pilot student was equipped with five electrodes, three-channel Holter (ECG BIOMEDICAL, BI9100). For this purpose, we have defined three-time phases: ground flight operations (bfo), in-flight operations (dfo) and post-flight ground operations (afo). The HRV analysis was carried out using the time domain and frequency domain parameters. As regards the mean of the RR intervals in the dfo, an increase was observed in 29% of the sample, while a decrease was observed in the remaining 71%, compared to that in the bfo. The analysis of the data relating to very low frequencies (VLF), low frequencies (LF) and high frequencies (HF) in the sample highlighted the values indicated below. In dfo, an increase in VLF values in 18% of the sample and a decrease in 82% in the remaining 71% compared to what was observed in bfo. LF values in dfo increased in 29% of the sample and decreased in the remaining 71%, compared to bfo. Finally, the HF, in dfo increased in 29% and decreased in 71% of cases, compared to the values of the bfo. Additional significant differences were found between the cases in which the RR intervals decreased in the dfo compared to the bfo, and those in which the RR intervals increased in the dfo compared to the bfo. In conclusion, the observed data lead to reconsider some physiological correlates of the different components involved in the determinism of HRV of a subject who carries out intense psychophysical activity for a certain period. In fact, it is necessary to evaluate the role of the ANS, in its various divisions (parasympathetic, sympathetic, and enteric), as well as the activity of the baroreceptors, the respiratory cycle (respiratory sinus arrhythmia), the thermoregulatory and hormonal factors within the short and medium tasks term.