Assessment Of Autonomic Nervous System Research Articles

Correlation between diminished vagal tone and somatic dysfunction severity in very and extremely low birth weight preterm infants assessed with frequency spectrum heart rate variability and salivary cortisol.

Osteopathic manipulative treatment (OMT) is evolving in the neonatal intensive care unit (NICU) setting. Studies showed its efficacy in length of stay and hospitalization costs reduction. Moreover, it was suggested that OMT has a modulatory effect on the preterm infants’ autonomic nervous system (ANS), influencing saturation and heart rate. Even if OMT is based on the palpatory examination of the somatic dysfunctions (SD), there are controversies about its identification and clinical relevance. The objective of this study was to evaluate the inter-rater reliability, clinical characteristics, and functional correlation of the SD Grade score with the heart rate variability (HRV) and the salivary cortisol (sCor) using a multivariate linear model approach. To evaluate those features, we implemented an ad hoc SD examination for preterm infants that was performed by 2 trained osteopaths. It was based on the new variability model of SD that includes an SD Grade assessment procedure. The ANS features were assessed by frequency parameters of HRV studying high frequency (HF), low frequency (LF), and HF/LF, whereas sCor was tested with a radioimmunoassay. The ANS assessment was standardized and performed before SD testing. Sixty-nine premature infants were eligible. SD Grade showed excellent concordance between the blinded raters. Using SD Grade as a grouping variable, the infants presented differences in GA, Apgar, pathological findings, length of stay, and ventilatory assistance. In our multivariate model, HF, LF, and LF/HF resulted linearly correlated with SD Grade. Instead, sCor presented a linear correlation with 5’ Apgar and respiratory distress syndrome but not with SD Grade. SD Grade was in line with the natural history of the underdevelopment due to prematurity. Our models indicate that the cardiac vagal tone is linearly related with SD Grade. This finding may improve the multidisciplinary decision making inside NICU and the management of modifiable factors, like SD, for cardiac vagal tone regulation.

Ранні діагностичні показники повернення до тренувально- змагальної діяльності у хокеїстів після черепно-мозкових травм

В дослідженні приймали участь 30 професійних гравців у хокей з шайбоюу віці від 17 до 30 років (середній вік склав 22,7±0,8) із струсом головного мозку у спорті.Спортсменам у день отримання струсу головного мозку у спорті призначали фізичний такогнітивний спокій. На наступний день спортсмени проходили огляд в об’ємі:соматоскопія та соматометрія, оцінку тонусу вегетативної нервової системи, оцінкуваріабельності серцевого ритму, оцінку відхилень балансу (BESS тест). Buffalo concussiontreadmill test, який є найбільш вживаним тестом з дозованим фізичним навантаженням, щовстановлює порогову частоту серцевих скорочень проводили на 3 день та 4 день.Результати проведеного дослідження показали зв’язок між струсом головного мозку успорті та змінами вегетативної регуляції у бік переважання симпатикотонії. Крім того,було показано динаміку стану вегетативної рівноваги протягом раннього періодувідновлення після струсу головного мозку. Також вдалося встановити покращеннярухових функцій після струсу головного мозку у динаміці з 1 візиту по 4. Проте, недивлячись на існуючі рекомендації щодо початку ранньої активної реабілітації на третійдень після струсу, не врахування стану вегетативної регуляції може призвести дофізичного перенапруження регулюючих систем. Це потребує врахування станувегетативної регуляції під час планування та виконання як реабілітаційних, так йспортивних навантажень у хокеїстів після струсу головного мозку у спорті.

Design and evaluation of an autonomic nerve monitoring system based on skin sympathetic nerve activity

The autonomic nervous system is closely related to cardiovascular diseases (CVDs). Simultaneous non-invasive recording of skin sympathetic nerve activity (SKNA) and electrocardiogram (ECG) is a new method for autonomic nervous system real-time assessment. This study presented a portable monitoring system based on SKNA. A system-level modification by combining a commercial analog front end (AFE) chip with a low-noise first-stage amplifier was implemented to reduce the system noise floor without a high-cost customized chip. An adaptive power-line-interference (PLI) filter and outliers clipping were developed to reject the PLI and motion artifacts in the signal. The laboratory experiment and clinical experiment were conducted to verify the performance and effectiveness of the proposed system. The laboratory results show that the proposed AFE has a much lower noise floor with 0.1 μVrms than the reference systems (PowerLab system). Moreover, the correlation coefficient of the envelope of SKNA (eSKNA) is 0.83, and the correlation coefficient of the heart rate variability (HRV) index is 0.99, suggesting a good performance in signal recording. The clinical results show that the proposed system can reflect sympathetic nerve activity significantly before and after anesthesia injection (p < 0.01), indicating its better feasibility in this application scenario than HRV-based devices (p = 0.40). The system achieves a comparable performance to the reference system and satisfactory performance for the autonomic nervous system assessment in clinical application.

Severity assessment of impairment in spinal cord injury; a systematic review on challenging points about International Standards for Neurological Classification of Spinal Cord Injury

Objective: Assessment of spinal cord injuries (SCI) severity is usually done according to the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). However, a limitation of ISNCSCI has not been thoroughly evaluate; therefore, a systematic review was performed to gather current evidence on the limitations of the ISNCSCI for assessing SCI. Methods: An extensive literature search was performed using Medline, Embase, Web of Science, Cochrane library, and Scopus for all articles up until the end of 2017 and then was updated to the end of 2020. Data was summarized by two independent reviewers and limitations of the ISNCSCI was further categorized. Results: 31 studies were included in the analysis. The limitations of ISNCSCI were classified into 6 domains: 1) lack of assessment of autonomic nervous system; 2) low value in assessing severity of SCI severity in children; 3) confounding factors which impact outcome are not accounted for by ISNCSCI; 4) lack of an established optimal cut off time point for administering the ISNCSCI; 5) low predictive and diagnostic value for assessing incomplete motor injuries; 6) poor classification and predictive value of the ISNCSCI. Conclusion: Although the ISNCSCI is a commonly used tool to assess the severity of SCI, there are several limitations.

Heart rate variability and cardiac autonomic functions in post-COVID period.

BackgroundThe heart rate variability (HRV) is a non-invasive, objective and validated method for the assessment of autonomic nervous system. Although acute manifestations of COVID-19 were widely researched, long-term sequela of COVID-19 are still unknown. This study aimed to analyze autonomic function using HRV indices in the post-COVID period that may have a potential to enlighten symptoms of COVID long-haulers.MethodsThe 24-h ambulatory electrocardiography (ECG) recordings obtained >12 weeks after the diagnosis of COVID-19 were compared with age–gender-matched healthy controls. Patients who used drugs or had comorbidities that affect HRV and who were hospitalized with severe COVID-19 were excluded from the study.ResultsTime domain indices of HRV analysis (standard deviation of normal RR intervals in 24 h (SDNN 24 h) and root mean square of successive RR interval differences (RMSSD)) were significantly higher in post-COVID patients (p < 0.05 for all). Among frequency domain indices, high frequency and low frequency/high frequency ratio was significantly higher in post-COVID patients (p = 0.037 and p = 0.010, respectively). SDNN >60 ms [36 (60.0%) vs. 12 (36.4%), p = 0.028)] and RMSSD >40 ms [31 (51.7%) vs. 7 (21.2%), p = 0.003)] were more prevalent in post-COVID patients. Logistic regression models were created to evaluate parasympathetic overtone in terms of SDNN >60 ms and RMSSD >40 ms. After covariate adjustment, post-COVID patients were more likely to have SDNN >60 msn (OR: 2.4, 95% CI:1.2–12.8) and RMSSD >40 ms (OR: 2.5, 95% CI: 1.4–9.2).ConclusionThis study revealed parasympathetic overtone and increased HRV in patients with history of COVID-19. This may explain the unresolved orthostatic symptoms occurring in post-COVID period which may be associated with autonomic imbalance.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10840-022-01138-8.

Double Product and Autonomic Function as Predictors of Quality of Life in Heart Transplant Recipients: A Cross-Sectional Study.

IntroductionHeart rate control by the autonomic nervous system (ANS) is impaired in heart transplant (HT) recipients, leading to increased resting heart rate, metabolic demand, and fatigue, which can impair their quality of life (QoL). In this study, we hypothesized the association of hemodynamics and autonomic function as predictors of QoL in HT recipients.MethodsThis is a cross-sectional study conducted with HT recipients aged ≥ 18 years at ambulatorial accompaniment. Blood pressure was used for hemodynamics assessment, and heart rate variability (HRV) was used for ANS assessment. QoL was assessed by the 36-item Short Form Health Survey. The significance level was set as P≤0.05.ResultsTwenty-two volunteers were included in the study. Systolic blood pressure (SBP) and double product (DP) were significantly negatively associated with the physical functioning domain of QoL. DP, the number of consecutive normal RR interval differences > 50 ms (NN50), and the percentage of normal RR intervals that differed by > 50 ms from the adjacent interval (PNN50) exhibited negative association with the physical role domain. NN50 and PNN50 were significantly associated with bodily pain, social functioning, and emotional role domains. SBP was negatively associated with the vitality domain. Considering general and mental health domains, no variable demonstrated significant association. DP, NN50, and PNN50 were negatively associated with the total score of QoL.ConclusionThis study demonstrated DP and HRV as predictors of QoL in HT recipients. These innovative results can become a relevant therapeutic target for improving QoL in HT recipients prior to its deterioration.

The Assessment of Autonomic Nervous System Activity Based on Photoplethysmography in Healthy Young Men.

Noninvasive assessment of autonomic nervous system (ANS) activity is of great importance, but the accuracy of the method used, which is primarily based on electrocardiogram-derived heart rate variability (HRV), has long been suspected. We investigated the feasibility of photoplethysmography (PPG) in ANS evaluation. Data of 32 healthy young men under four different ANS activation patterns were recorded: baseline, slow deep breathing (parasympathetic activation), cold pressor test (peripheral sympathetic activation), and mental arithmetic test (cardiac sympathetic activation). We extracted 110 PPG-based features to construct classification models for the four ANS activation patterns. Using interpretable models based on random forest, the main PPG features related to ANS activation were obtained. Results showed that pulse rate variability (PRV) exhibited similar changes to HRV across the different experiments. The four ANS patterns could be better classified using more PPG-based features compared with using HRV or PRV features, for which the classification accuracies were 0.80, 0.56, and 0.57, respectively. Sensitive features of parasympathetic activation included features of nonlinear (sample entropy), frequency, and time domains of PRV. Sensitive features of sympathetic activation were features of the amplitude and frequency domain of PRV of the PPG derivatives. Subsequently, these sensitive PPG-based features were used to fit the improved HRV parameters. The fitting results were acceptable (p < 0.01), which might provide a better method of evaluating ANS activity using PPG.

P-38 UTILITY OF PUPILLARY REACTIVITY IN THE FUNCTIONAL ASSESSMENT OF THE AUTONOMOUS NERVOUS SYSTEM IN PATIENTS WITH CHRONIC LIVER DISEASE: PRELIMINARY RESULTS

Autonomic nervous system (ANS) dysfunction in patients with chronic liver disease (CLD) is associated with greater severity. Heart rate variability (HRV) allows the assessment of ANS, but its implementation is complex. Pupillary reactivity (PR) by automatic pupillometry (AP) also provides this information; however its usefulness in patients with CLD is unknown. To validate the usefulness of PR in the evaluation of ANS in healthy subjects and patients with CLD through association with HRV. Cross-sectional study that includes healthy controls (n = 11) and patients with DHC (n = 26). ANS balance was determined by HRV by Holter rhythm of 5 minutes and RP by AP. HRV / RP of healthy subjects and with CLD, and correlation parameters of both measurements were compared. Significant differences were found between both groups in the parameters of both HRV and RP, demonstrating an imbalance of the ANS in CLD patients. Differences were significant in 2 of 3 time parameters, in 2 of 3 frequency parameters in HRV and in 5 of 7 objectified by AP. The imbalance increases directly according to the Child stage (p <0.001). Patients with CLD have an unbalanced ANS and AP was useful in this study to demonstrate this. The most altered parameters in patients with DHC are directly correlated with the function of the parasympathetic ANS.

Device for Controlling Stimulus Self-Application During Autonomic Nervous System Tests.

Assessment of autonomic nervous system (ANS) functioning may be performed non-invasively using autonomic tests which are based on evaluation of response of cardiovascular system to the applied stimuli, such as increased air pressure during Valsalva maneuver, skeletal muscle contraction during static handgrip or deep slow breathing. The cardiovascular response depends, besides ANS reaction and test protocol, also on the way stimulus is self-applied by the test subject. We present a versatile device for controlling stimulus self-application during three ANS tests: Valsalva maneuver, static handgrip, and deep breathing. It integrates two different gauges and a pace setter for breathing into one device. The core of the device is a linear LED display which, using green, yellow, and red diodes, informs the subject about the correctness of self-application of respective stimulus. The settings of the device can be adjusted to the needs of the protocol chosen. The device can record the duration of mouth air pressure or the force produced by the subject during ANS tests, which assures correctness of the tests, thus allowing to track individual variability changes in the response to the test. The device was verified during ANS tests and its use was intuitive for patients, reducing the time needed for training before tests and decreasing the effort of the physician.

Autonomic nervous modulation after cryoballoon ablation for paroxysmal atrial fibrillation

Aim. Aim of our study was the assessment of autonomic nervous system (ANS) modulation by assessment of heart rhythm variation (HRV) using Holter monitoring after single second generation cryoballoon ablation (CBA) for paroxysmal atrial fibrillation (AF).Methods. Patients who underwent the CBA for paroxysmal AF were include in this study. At the baseline the Holter monitoring after withdrawal of antiarrhythmic therapy (AAT) with assessment of HRV: SDNN, RMSSD, ln LF, ln LH, LH/HF, mean, minimal and maximal beats per minute (BPM) was perform. Follow-up was based on outpatient clinic visits at 3, 6, and 12 months including Holter monitoring.Results. Among 80 patients underwent CBA, HRV was assessed in 55 patients (65.5% male, age median 61 years, 97.7% of pulmonary vein have been successful isolated). One year after CBA all HRV parameters and the mean, minimal and maximal BPM was significantly different from baseline parameters (p&lt;0.05). In the AF recurrence group ln LF was lower at 3-, 6and 12-month visits (p&lt;0.05) and minimal HR was higher at 3 months (median 58 vs 55.5, p=0.033). Multivariate analysis demonstrated that early recurrence of AF was independent predictor of AF recurrence after CBA (HR 7,44, 95% CI 2,19-25,25, р=0,001).Conclusion. Our study demonstrated that CBA leads to modulation of ANS which persists for at least 12 months. The early recurrence of AF was only predictor of AF recurrence after CBA.

The role of stress reactivity and pre-injury psychosocial vulnerability to psychological and physical health immediately after traumatic injury

BackgroundTraumatic injuries can have long-term negative impacts on health, especially psychological health. A biopsychosocial approach is recommended to identify those likely to experience psychosocial stress, however large individual differences exist in stress reactivity and post-injury health that remain unexplored. Therefore, we investigated autonomic nervous system (ANS) stress responses and pre-existing psychosocial vulnerability as contributors to health in individuals who sustained a traffic-related injury. Methods120 adults with traffic-related injury and 112 non-injury controls underwent an integrative ANS (cardiac and skin conductance) assessment and a health-related assessment at 3–6 weeks post-injury. Propensity score matching based on six pre-injury psychosocial vulnerability factors (age, sex, education, prior mental/physical health, socioeconomic status) guided the definition of high vulnerability (HV) and low vulnerability (LV) injury subgroups, with the LV subgroup having similar propensity scores to non-injury controls. A three-group comparative analysis of ANS responsivity (baseline, reactivity, recovery/rebound) and post-injury health was performed. ResultsThe HV subgroup exhibited the most negative immediate post-injury mental health profile and less adaptive ANS response patterns, indicating greater stress vulnerability/reactivity. Significant differences were found for psychological health (elevated psychological distress and catastrophizing), but not physical health (injury factors, pain, fatigue, physical wellbeing). HV participants showed sympathetic predominance at resting baseline (lower parasympathetic activity and/or elevated heart rate) compared to the LV and control groups, as well as smaller parasympathetic decrease during a cognitive task compared to controls. Despite preserved capacity for restoring initial homeostasis in both injury subgroups during recovery, there was some indication of blunted post-task sympathetic deactivation (larger sympathetic decrease) and reduced overall ANS adaptability (reduction in total power of heart rate variability spectrum), suggesting relative reduced capacity to face stressors compared to controls. ConclusionsFindings suggest that baseline resting ANS regulation, particularly parasympathetic activity, and pre-injury psychosocial factors are key contributors to individual psycho-biological responses following traumatic injury, and are therefore potential stress vulnerability markers. Post-stress recovery patterns may represent a novel physiological signature for a “biological intrinsic” vulnerability early after the injury. These findings provide direction for improved early identification and management of injured individuals, including innovative preventive interventions that target ANS regulation.

Does autonomic nervous system dysfunction influence cardiovascular disease risk in young adults with intellectual disability?

People with intellectual disability (ID) experience cardiometabolic-related morbidity and mortality. However, it has been suggested that this population presents and lives with underestimated cardiovascular risk factors at a younger age, hence affecting their overall health and quality of life and contributing to early mortality. We assessed autonomic nervous system function in subjects with ID (n = 39), aged 18-45 yr, through measures of sudomotor function, heart rate and systolic blood pressure variability, and cardiac baroreflex function. Traditional clinical cardiovascular measurements and a biochemical analysis were also undertaken. We found that young adults with ID presented with sudomotor dysfunction, impaired cardiac baroreflex sensitivity, and systolic blood pressure variability, when compared with age-matched control subjects (n = 38). Reduced hand and feet electrochemical skin conductance and asymmetry were significantly associated with having a moderate-profound ID. Autonomic dysfunction in individuals with ID persisted after controlling for age, sex, and other metabolic parameters. Subjects in the ID group also showed significantly increased blood pressure, body mass index, and waist/hip circumference ratio, as well as increased plasma hemoglobin A1c and high-sensitivity C-reactive protein levels. We conclude that autonomic dysfunction is present in young adults with ID and is more marked in those with more severe disability. These finding have important implications in developing preventative strategies to reduce the risk of cardiovascular disease in people with ID.NEW & NOTEWORTHY Adults with intellectual disability experience higher risk of premature death than the general population. Our investigation highlights increased cardiovascular risk markers and autonomic dysfunction in young adults with intellectual disability compared with control adults. Autonomic dysfunction was more marked in those with a more severe disability but independent of cardiovascular parameters. Assessment of autonomic nervous system (ANS) function may provide insight into the mechanisms of cardiometabolic disease development and progression in young adults with intellectual disability.

R-Wave Singularity: A New Morphological Approach to the Analysis of Cardiac Electrical Dyssynchrony.

R-wave singularity (RWS) measures the intermittence or discontinuousness of R waves. It has been broadly used in QRS (QRS complex of electrocardiogram) detection, electrocardiogram (ECG) beats classification, etc. In this article, we novelly developed RWS to the analysis of QRS morphology as the measurement of ventricular dyssynchrony and tested the hypothesis that RWS could enhance the discrimination between control and acute myocardial infarction (AMI) patients. Holter ECG recordings were obtained from the Telemetric and Holter ECG Warehouse database, among which database Normal was extracted as normal controls (n = 202) and database AMI (n = 93) as typical subjects of autonomic nervous system dysfunction and cardiac electrical dyssynchrony with high risk for cardiac arrhythmias and sudden cardiac death. Experimental results demonstrate that RWS measured by Lipschitz exponent calculated from 5-min Holter recordings was significantly less negative in early AMI and late AMI than that in Normal subjects for overall, elderly, and elderly male groups, which suggested the heterogeneous depolarization of the ventricular myocardium during AMI. Receiver operating characteristic curve analyses show that combined with heart rate variability parameters, Lipschitz exponent provides higher accuracy in distinguishing between the patients with AMI and healthy control subjects for overall, elderly, elderly male, and elderly female groups. In summary, our study demonstrates the significance of using RWS to probe the cardiac electrical dyssynchrony for AMI. Lipschitz exponent may be valuable and complementary for existing cardiac resynchronization therapy and autonomic nervous system assessment.

DIAGNOSTIC POTENTIAL OF SELECTED SALIVARY PROTEOMICS FOR AUTONOMIC NERVOUS SYSTEM ACTIVITY ASSESSMENT

The clinical assessment of autonomic nervous system (ANS) functioning, enabling the diagnosis of autonomic neuropathy present in the course of many diseases, is currently based on performing simple cardiovascular reflexes (Ewing tests), analyzing heart rate variability (HRV) or heart rate turbulence (HRT), examining skin sweating or recording neurophysiological tests (e.g. microneurography). Laboratory assessment of ANS function is very scarce and practically only includes the plasma assessment of noradrenaline as a surrogate for the biochemical indicator of sympathetic activity. Recently, the possibility of evaluation of selected compounds present in saliva as laboratory markers of not only oral diseases but also systemic diseases has been raised. This work focuses on a brief description of the anatomy and physiology of the salivary glands and describes the formation of saliva, its composition and the use of this bodily fluid in laboratory diagnostics. In addition, the paper specifically discusses the possibility of determining selected compounds that are considered to reflect autonomic activity. A review of the literature indicates primarily four proteomics: two neuropeptides (vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) that are co-transmitters in autonomic fibers, chromogranin A, a synaptic vesicle protein and α-amylase, a hydrolytic enzyme pre-digesting carbohydrates in the oral cavity. These are currently the most widely investigated agents for their usefulness as laboratory markers of ANS activity.

Assessment of Autonomic Nervous System in Children with Celiac Disease: A Heart Rate Variability Study

We evaluated the activity of autonomic nervous system in children with celiac disease by using heart rate variability (HRV) analysis. HRV parameters of 37 children with celiac disease were compared to 36 age- and sex-matched healthy controls. None of the participants had a systemic, central or peripheral neurological disease. Statistically significant differences were present in two parameters; standard deviation of all RR intervals (SDNN) and standard deviation of 5-minute RR interval means (SDANN). Age was negatively correlated with mean, minimum and maximum heart rate. Duration of disease was positively correlated with low frequency power-high frequency power ratio. No correlation was found between anti-tissue transglutaminase IgA level and HRV parameters. Celiac disease may affect autonomic nervous function in children even if there are no symptoms of dysautonomia.

Assessing Autonomic Function from Electrodermal Activity and Heart Rate Variability During Cold-Pressor Test and Emotional Challenge

Standard functional assessment of autonomic nervous system (ANS) activity on cardiovascular control relies on spectral analysis of heart rate variability (HRV) series. However, difficulties in obtaining a reliable measure of sympathetic activity from HRV spectra limits the exploitation of sympatho-vagal metrics. On the other hand, measures of electrodermal activity (EDA) have been demonstrated to provide a reliable quantifier of sympathetic dynamics. In this study we propose novel indices of phasic autonomic regulation mechanisms by combining HRV and EDA correlates and thoroughly investigating their time-varying dynamics. HRV and EDA series were gathered from 26 healthy subjects during a cold-pressor test and emotional stimuli. Instantaneous linear and nonlinear (bispectral) estimates of vagal dynamics were obtained from HRV through inhomogeneous point-process models, and combined with a sensitive maker of sympathetic tone from EDA spectral power. A wavelet decomposition analysis was applied to estimate phasic components of the proposed sympatho-vagal indices. Results show significant statistical differences for the proposed indices between the cold-pressor elicitation and previous resting state. Furthermore, an accuracy of 73.08% was achieved for the automatic emotional valence recognition. The proposed nonlinear processing of phasic ANS markers brings novel insights on autonomic functioning that can be exploited in the field of affective computing and psychophysiology.

Intrapartum PRSA: a new method to predict fetal acidosis?-a case-control study.

Phase-rectified signal averaging method (PRSA) represents an analysis method which applied on fetal cardiotocography (CTG) allows the quantification of the speed of fetal heart rate changes. By calculating the average deceleration capacity (ADC) an assessment of the fetal autonomic nervous system (ANS) is possible. The objective of this study was to test its ability to predict perinatal acidosis. A case-control study was performed at a University Hospital in Munich. All intrapartum CTG heart rate tracings saved during a 7-year period were considered for analysis. All neonates born with an umbilical arterial blood pH ≤ 7.10 were considered as cases. Controls were defined as healthy fetuses born with a pH ≥ 7.25. The main matching criteria were gestational age at delivery, parity, birth mode, and birth weight percentile. Exclusion criteria were a planned caesarean section, fetal malformations, and multiple pregnancies. ADC and STV were then calculated during the last 60, the last 45, and the last 30min intervals prior to delivery. Of all stored birth CTG recordings, 227 cases met the inclusion criteria and were studied. ADC was significantly higher in fetuses born with acidemia (4.85bpm ± 3.0) compared to controls (3.36bpm ± 2.2). The area under ROC curve was 0.659 (95% CI 0.608-0.710) for ADC and 0.566 (0.512-0.620) for STV (p = 0.013). This study confirms that the assessment of ADC using PRSA represents a good additional tool for the prediction of acute fetal acidosis during delivery.

Obstructive Sleep Apnea Recognition Based on Multi-Bands Spectral Entropy Analysis of Short-Time Heart Rate Variability.

Obstructive sleep apnea (OSA) syndrome is a common sleep disorder. As an alternative to polysomnography (PSG) for OSA screening, the current automatic OSA detection methods mainly concentrate on feature extraction and classifier selection based on physiological signals. It has been reported that OSA is, along with autonomic nervous system (ANS) dysfunction and heart rate variability (HRV), a useful tool for ANS assessment. Therefore, in this paper, eight novel indices of short-time HRV are extracted for OSA detection, which are based on the proposed multi-bands time-frequency spectrum entropy (MTFSE) method. In the MTFSE, firstly, the power spectrum of HRV is estimated by the Burg–AR model, and the time-frequency spectrum image (TFSI) is obtained. Secondly, according to the physiological significance of HRV, the TFSI is divided into multiple sub-bands according to frequency. Last but not least, by studying the Shannon entropy of different sub-bands and the relationships among them, the eight indices are obtained. In order to validate the performance of MTFSE-based indices, the Physionet Apnea–ECG database and K-nearest neighbor (KNN), support vector machine (SVM), and decision tree (DT) classification methods are used. The SVM classification method gets the highest classification accuracy, its average accuracy is 91.89%, the average sensitivity is 88.01%, and the average specificity is 93.98%. Undeniably, the MTFSE-based indices provide a novel idea for the screening of OSA disease.

Longitudinal assessment of autonomic nervous system in patients with first demyelinating event suggestive of multiple sclerosis.

As a high proportion of people with clinically isolated syndrome (pwCIS) exhibit sympathetic adrenergic and sudomotor dysfunction, the aim of this study was to investigate the evolution of autonomic nervous system (ANS) abnormalities in pwCIS over a 2-year follow-up. This was a prospective cohort study in which 121 pwCIS were enrolled and followed for 2years. After 2-year follow-up, data were available for 84 pwCIS. ANS symptoms were evaluated with the Composite Autonomic System Score-31 (COMPASS-31) and results of the ANS tests were expressed using the Composite Autonomic Scoring Scale (CASS) at baseline and visit at month 24. Symptomatic dysautonomia was defined if the patient had a COMPASS-31 value above the median of the whole cohort at baseline evaluation (COMPASS-31>6.79) and CASS score >0. Complete CASS data at baseline and month 24 were available for 62 patients; in 24 (38.7%) patients there was worsening, in 16 (25.8%) there was improvement and in 22 (35.5%) there was no change in CASS score. In 90% of pwCIS (72 of 80) there was no change in parasympathetic nervous system tests, whereas 47.3% (35 of 74) had either worsening or improvement in sympathetic adrenergic and 28.6% (20 of 70) had either worsening or improvement in sudomotor function. A multivariable regression model identified the total number of T2 lesions as an independent predictor for worsening of symptomatic dysautonomia. No predictors for worsening or improving of CASS score were identified. A substantial proportion of pwCIS experienced worsening of ANS abnormalities during the 2-year follow-up and magnetic resonance imaging parameters seemed to predict these abnormalities.

The Impact Of Acute Hyperglycemia On Heart Rate Variability In Men And Women.

BACKGROUND: Heart rate variability (HRV) is used to non-invasively assess autonomic nervous system (ANS) regulation of the heart. Chronic hyperglycemia has been known to reduce HRV; however, no research has examined the impact of acute hyperglycemia on HRV, considering the potential for sex- and menstrual cycle phase-based differences. PURPOSE: To examine the impact of acute hyperglycemia on HRV, in men and women during the early and late follicular phases of the menstrual cycle. METHODS: 41 healthy men and naturally menstruating women (17F, age: 21±1 years) were recruited. Women were assessed during the early and late follicular phases of the menstrual cycle. ‘Ultra short-term’ assessments of HRV (1-minute recordings) were completed using an electrocardiogram before, and 60- and 90-min after consuming a 75g oral glucose challenge. Analysis of HRV time-domain variables was performed. RESULTS: Acute hyperglycemia resulted in elevated HR (shorter R-R intervals) at 60- and 90-min post-glucose ingestion (Pre: 61±1, Post60: 65±1, Post90: 66±1 bpm; p=0.005, p<0.001 respectively), with no differences between men and women, or across phases of the menstrual cycle. The root mean square of successive differences between R-R intervals (RMSSD) and standard deviation in normal R-R intervals (SDNN) were significantly lower Post90 vs Pre (p=0.022, p=0.048 respectively), with no sex differences. Additionally, women, regardless of phase, had higher average HR compared to men (p<0.001). CONCLUSION: Acute hyperglycemia appears to decrease HRV, indicative of an acute change in ANS regulation. Furthermore, this study confirmed previously observed sex differences in HR, but not in HRV. Research supported by: NSERC Discovery Grant & Canadian Graduate Scholarship - Master’s