Parasympathetic Function Research Articles

A Study of Parasympathetic Autonomic Function in Different Phases of the Menstrual Cycle among Young Adult Females

Background: The sex hormones, estrogen, and progesterone, as well as the gonadotropins, luteinizing hormone, and follicle-stimulating hormone produced from the anterior pituitary, govern the three stages of the menstrual cycle: menstrual, follicular, and luteal. Hormone fluctuations cause changes in autonomic function. There have been relatively few studies that show autonomic function modification throughout various periods of the menstrual cycle. Aim and Objectives: The current study was undertaken to investigate the difference in mean parasympathetic autonomic characteristics between the proliferative and secretory stages of the menstrual cycle. Materials and Methods: A total of 120 healthy young adult female volunteers were recruited among Kalinga Institute of Medical Sciences, Kalinga Institute of Nursing Sciences, and Kalinga Institute of Dental Sciences students. The study eliminated 20 students who were in the bleeding phase of their cycle. The electrocardiogram was captured, and parasympathetic parameters were determined using the fully automated CANWin instrument in the Department of Physiology. The data of the abovementioned parameters were compiled, tabulated, and entered into Microsoft Excel 2013 and statistically analyzed using STATA software 15.1. Results: The subjects’ mean ages, heights, and weights were 18.9 ± 0.70 years, 156.6 ± 5.25 cm, and 53.7 ± 8.63 kg, respectively. The mean resting heart rate in the secretory phase was substantially greater than in the proliferative phase, indicating sympathetic dominance. The 30:15 ratio between proliferative and secretory stages. The mean E: I ratio calculated from the slow deep breathing maneuver reveals a statistically significant difference between the proliferative and secretory phases. Conclusion: During the secretory phase, there is a considerable rise in parasympathetic activity among the individuals in the current study. Changes in parasympathetic activity throughout the follicular and secretory stages of the menstrual cycle may be caused by fluctuations in estrogen and progesterone levels.

Brief Report: Changes in Nocturnal Heart Rate Variability in People Living With HIV During the First Year of Antiretroviral Therapy Compared With HIV-Uninfected Community Controls.

Higher nocturnal heart rate and lower nocturnal heart rate variability (HRV) is associated with increased cardiovascular disease mortality. Longitudinal studies on nocturnal HRV in people living with HIV (PLWH) are lacking. We conducted a 1-year prospective cohort study of adult PLWH and HIV-uninfected community controls in northwestern Tanzania. At enrollment, we collected data on cardiovascular risk factors and tested blood samples for hemoglobin, insulin, CD4 cell count, and C-reactive protein. We measured nocturnal HRV and heart rate at baseline and first-year follow-up. Mixed effect linear regression was used to determine predictors of lower HRV. Of the 111 enrolled participants (74 PLWH and 37 HIV-uninfected adults), 57.7% were female and the median age was 40 years. Over 1 year of follow-up, the average nocturnal heart rate was 4.5 beats/minute higher in PLWH ( P = 0.006). In the fully adjusted model (with age, sex, nocturnal heart rate, and diabetes), average nocturnal HRV was 10.5 milliseconds lower in PLWH compared with HIV-uninfected adults ( P = 0.03). Unlike with nocturnal heart rate, nocturnal HRV did not improve after 1 year of ART in PLWH or HIV-uninfected adults (fully adjusted change = -2.5 milliseconds, P = 0.45). Lower educational attainment, lesser pancreatic β-cell function, and anemia were associated with higher HRV. Nocturnal parasympathetic nervous system function was persistently lower in PLWH compared with HIV-uninfected adults even after antiretroviral therapy initiation. Improving nocturnal autonomic nervous system function could be a target for cardiovascular disease prevention in PLWH.

Vagal Flexibility Moderates the Links between Observed Sensitive Caregiving in Infancy and Externalizing Behavior Problems in Middle Childhood.

This study explored how patterns of physiological stress reactivity underpin individual differences in sensitivity to early rearing experiences and childhood risk for psychopathology. To examine individual differences in parasympathetic functioning, past research has largely relied on static measures of stress reactivity (i.e., residual and change scores) in infancy which may not adequately capture the dynamic nature of regulation across contexts. Using data from a prospective longitudinal study of 206 children (56% African Americans) and their families, this study addressed these gaps by employing the latent basis growth curve model to characterize the dynamic, non-linear patterns of change in infants' respiratory sinus arrhythmia (i.e., vagal flexibility) across the Face-to-Face Still-Face Paradigm. Furthermore, it investigated whether and how infants' vagal flexibility moderates the links between sensitive parenting, observed during a free play task when children were 6 months of age, and parent-report of children's externalizing problems at 7 years of age. Results of the structural equation models revealed that infants' vagal flexibility moderates the predictive relations between sensitive parenting in infancy and children's later externalizing problems. Simple slope analyses revealed that low vagal flexibility, characterized by less suppression and flatter recovery patterns, exacerbated risk for externalizing psychopathology in the context of insensitive parenting. Children with low vagal flexibility also benefited most from sensitive parenting, as indicated by the lower number of externalizing problems. Findings are interpreted in the light of the biological sensitivity to context model and provide evidence for vagal flexibility as a biomarker of individual's sensitivity to early rearing contexts.

Gender difference in parasympathetic function by HRR1min after graded treadmill exercise in healthy obese young adults

Background: Heart rate recovery at 1st min (HRR1min) following exercise, an indicator of parasympathetic function is found to be impaired in obese children, adolescents, and elderly people. In children, adolescents and elderly people impaired that HRR1min was significantly associated with obese females (OF) than in males. This study aims at establishing the gender difference in HRR1min among obese young adults (18–30 years age). Aims and Objectives: This study was conducted to assess parasympathetic function by HRR1min after graded exercise, in apparently healthy obese young adult males and females and to evaluate for gender difference in them. Materials and Methods: Fifty obese young adults (25 males and 25 females with body mass index [BMI] ≥30) and 50 age- and gender-matched controls (25 males and 25 females with BMI ≤24.9) were subjected to graded treadmill exercise. Maximum heart rate reached during exercise and heart rate at 1st min of recovery phase were recorded and HRR1min was calculated as the difference of above. The data were analyzed. Results: The study showed significant decrease in mean HRR1min in obese males compared to OF (mean 18.04±3.6 vs. 30.00±8.55, P<0.001), there is significant delay in HRR1min when OF and males were compared with their gender-matched controls. Conclusion: Parasympathetic function by HRR1min after exercise is significantly decreased in male obese young adults when compared with female obese young adults and are at higher risk of developing metabolic syndrome and cardiovascular disorders.

ID: 212169 Treating Generalized Anxiety Disorder With HRV-Mimetic Transcranial Alternating Current

Heart rate variability (HRV), the beat-to-beat changes in the heartbeat, is a nested component of the heartbeat evoked potential that entrains cortical activity in perceptual and emotional-related regions. Generalized anxiety disorder (GAD) is associated with a decreased HRV suggestive of an impairment in brain-body synchrony and parasympathetic function. Our study is, thus, a targeted restoration of neurotypical parasympathetic function and brain-body synchrony. There is potential in utilizing the cross-frequency relationships between EEG and endogenous rhythms for quantifying holistic health and designing interventions targeting these substrates.

Parasympathetic autonomic dysfunction is more often evidenced than sympathetic autonomic dysfunction in fluctuating and polymorphic symptoms of "long-COVID" patients

Several disabling symptoms potentially related to dysautonomia have been reported in “long-COVID” patients. Unfortunately, these symptoms are often nonspecific, and autonomic nervous system explorations are rarely performed in these patients. This study aimed to evaluate prospectively a cohort of long-COVID patients presenting severe disabling and non-relapsing symptoms of potential dysautonomia and to identify sensitive tests. Autonomic function was assessed by clinical examination, the Schirmer test; sudomotor evaluation, orthostatic blood pressure (BP) variation, 24-h ambulatory BP monitoring for sympathetic evaluation, and heart rate variation during orthostatism, deep breathing and Valsalva maneuvers for parasympathetic evaluation. Test results were considered abnormal if they reached the lower thresholds defined in publications and in our department. We also compared mean values for autonomic function tests between patients and age-matched controls. Sixteen patients (median age 37 years [31–43 years], 15 women) were included in this study and referred 14.5 months (median) [12.0–16.5 months] after initial infection. Nine had at least one positive SARS-CoV-2 RT-PCR or serology result. Symptoms after SARS-CoV-2 infection were severe, fluctuating and disabling with effort intolerance. Six patients (37.5%) had one or several abnormal test results, affecting the parasympathetic cardiac function in five of them (31%). Mean Valsalva score was significantly lower in patients than in controls. In this cohort of severely disabled long-COVID patients, 37.5% of them had at least one abnormal test result showing a possible contribution of dysautonomia to these nonspecific symptoms. Interestingly, mean values of the Valsalva test were significantly lower in patients than in control subjects, suggesting that normal values thresholds might not be appropriate in this population.

38 Heart rate variability as a predictor of racing performances in standardbred horses

Heart Rate Variability (HRV) is a non-invasive tool for assessing the autonomic regulation of heart rate through variations in RR-intervals. It reflects the control of parasympathetic and sympathetic autonomic functions in the cardiovascular system. In humans, HRV is used to adjust exercise training for improving performance. Also, some HRV parameters have been correlated to running performance and fitness status. In horses, although HRV has been used to assess behavioral response to stress, little is known regarding its correlation with performance. This experiment aimed to investigate if resting values of HRV correlate to racing performance in Standardbred horses. Forty-eight horses (27 stallions, 4 geldings and 17 mares; 2 to 7 years old; 2 to 95 races run) from Hunter Valley stables were followed over one year. Electrocardiograms were recorded twice (6 mo apart) using heart rate monitors Equimetre (Arioneo, France) for 10 min in the early morning when horses were in individual stalls. Horses did not undergo intense exercise the day before data collection. Analysis of HRV parameters was performed on Kubios HRV software to determine Standard Deviation (SDNN), Root Mean Square of Successive Differences (RMSSD), number of successive intervals differing more than 50ms (pNN50) and Standard Deviation from Poincaré plot (SD1 and SD2). Racing performances (total earnings, earnings perrace, racing time) were collected from LeTrot database for each horse over the whole career, and close to the day of measurement (one month before to 2 mo after). Performance and HRV parameters were correlated using Pearson coefficients, and linear regressions were performed to predict racing performances. Best time in career and close to HRV measurement were negatively correlated to SDNN, RMSSD, pNN50, SD1 and SD2 (P < 0.01; −0.46P < 0.03; 0.27 > r > 0.35). Total earnings and earnings per race during the 3 mo close to HRV measurement were correlated with RMSSD, pNN50 and SD1 (P < 0.05; 0.29 > r > 0.52). Prediction of total earnings and earnings per race from the HRV parameters within 3 mo close to the measure was modest (adjusted R2 = 0.31 and 0.24; P = 0.0004 and 0.0016 respectively). In human athletes, higher HRV parameters indicate greater parasympathetic tone, better training adaptation and increased recovery. In our study, horses with higher HRV parameters possibly also recovered better, as the trainer decided to make them race more (P < 0.01; R > 0.36). Further research focusing on inter-individual variations to accurately track the horses' training and schedule the racing program would be valuable.

Diagnosis and treatment of the otitis externa and media

Diagnosis and treatment of the otitis externa and media

EVALUATION OF CARDIOVASCULAR AUTONOMIC FUNCTION TESTS IN OBESE AND NON-OBESE HEALTHY INDIANS

Autonomic nervous system (ANS) is a centre for the coordination of different body systems. Since the ANS is involved in energy metabolism and in the regulation of almost all visceral systems. It is conceivable that one or more subgroups of persons with idiopathic obesity have an alteration in their autonomic nervous system that may account for several clinical consequences of obesity. This observational study was conducted to find the association of Autonomic Function Tests among obese and non-obese participants. Among 90 participants, 45 were obese and 45 were non-obese, aged 18-40 years of either gender was enrolled after getting their voluntary written consent. In both the groups, Cold Pressure Test and Hand Grip Test were performed for evaluating sympathetic functions. Standing test (30:15 RR Ratio), Standing to Lying ratio, and Valsalva ratio were performed for evaluating parasympathetic functions. Chi-square and unpaired t test was employed for statistical analysis. A statistically significant association of Autonomic Function Tests among obese and non-obese participants was found as per BMI and Body Fat Percentage criteria. Study explored that obesity was associated with ANS dysfunction as compared to non-obese; this relationship was observed primarily in terms of sympathetic and parasympathetic activity. The results of this study are indicative of autonomic insufficiency among obese participants.

Examining the Relations Between Children's Vagal Flexibility Across Social Stressor Tasks and Parent- and Clinician-Rated Anxiety Using Baseline Data from an Early Intervention for Inhibited Preschoolers.

Early behavioral inhibition (BI) is a known risk factor for later anxiety disorder. Variability in children's parasympathetic nervous system (PNS) functioning may provide insight into the substantial heterogeneity in anxiety outcomes for children high in BI. However, gaps persist due to an over-reliance on static measures of functioning, which limits our ability to leverage PNS functioning to identify risk for anxiety. We address these gaps using baseline data from an early intervention study of inhibited preschoolers by characterizing vagal flexibility (VF), an index of non-linear change in PNS functioning, across social stressor tasks and by examining the associations between VF and anxiety. One hundred and fifty-one parents and their 3.5- to 5-year-old children were selected on the basis of BI to participate in an early intervention program (ClinicalTrials.gov registration: NCT02308826). A structural equation modeling framework was used to model children's VF across tasks designed to mimic exposure to novel social interactions and to test the predictive links between VF and anxiety. Children who showed less VF, characterized by less suppression and flatter recovery, were rated by both parents and clinicians as more anxious. Moreover, a multiple group model showed that children meeting diagnostic criteria for social anxiety disorder demonstrated significantly less VF across social stressor tasks. Among inhibited youth, reduced VF is a risk factor for anxiety and may reflect an individual's reduced capacity to actively cope with external demands. Study results contribute to our understanding of the regulatory processes underlying risk for anxiety in early childhood.

Allostatic Load and Depression Symptoms in Cancer Survivors: A National Health and Nutrition Examination Survey Study.

Individuals with cancer often experience stress throughout the cancer trajectory and have a high risk of experiencing depression. The aim of this study was to examine the relationship between allostatic load (AL), a measure of cumulative stress-related physiologic dysregulation of different body systems, and symptoms of depression in cancer survivors. Participants were 294 adult cancer survivors from the US National Health and Nutrition Examination Survey (NHANES 2007-2018). Allostatic load was measured using 14 indicators representing cardiometabolic risk, glucose metabolism, cardiopulmonary functioning, parasympathetic functioning, and inflammation. Depressive symptoms were measured with the Patient Health Questionnaire-9. The relationship between AL and depressive symptoms was investigated using multiple regression adjusted for diverse sociodemographic and diagnosis variables. Higher AL was associated with higher depressive symptom scores. The higher risk of depression was concentrated among those survivors in the highest AL quartile, with 21% (95% confidence interval, 11%-32%) of survivors presenting a high risk of depression compared with 8% to 11% of survivors in the lower quartiles. In exploratory analyses, the relationship between AL and depressive symptoms was only significant among survivors with a lower income. In contrast, in survivors in the highest income group, depressive symptoms were lower and unrelated to AL. High AL is associated with more depressive symptoms among cancer survivors. Nurses have an important role in identifying psychological distress in cancer patients and survivors. Further research is needed to investigate the usefulness of AL as a marker in the context of cancer follow-up care and screening for psychological distress.

Demonstrating new-onset or worsened sudomotor function post-COVID-19 on comparative analysis of autonomic function pre-and post-SARS-CoV-2 infection.

Autonomic dysfunction including sudomotor abnormalities have been reported in association with SARS-CoV-2 infection. There are no previous studies that have compared autonomic function objectively in patients pre- and post- SARS-CoV-2 infection.We aimed to identify if SARS-CoV-2 virus is triggering and/or worsening dysautonomia by comparing autonomic function tests in a group of patients pre-and post-SARS-CoV-2 infection. Six participants were enrolled and divided into two groups. The first group of 4 participants reported worsened autonomic symptoms post-SARS-CoV-2 infection. These individuals had their first autonomic test prior to COVID-19 pandemic outbreak (July 2019-December 2019). Autonomic function testing was repeated in these participants, 6months to 1-year post-SARS-CoV-2 infection (June 2021).The second group of 2 participants reported new-onset autonomic symptoms post-COVID-19 infection and were also tested within 6months post-SARS-CoV-2 infection.All participants had mild COVID-19 infection per WHO criteria. They had no evidence of large fiber neuropathy as demonstrated by normal neurophysiological studies (EMG/NCS). They were all screened for known causes of autonomic dysfunction and without risk factors of hypertension/hyperlipidemia, thyroid dysfunction, diabetes/prediabetes, vitamin deficiencies, history of HIV, hepatitis, or syphilis, prior radiation or chemical exposure or evidence of monoclonal gammopathy, or autoimmune condition. Participants were female (age: 21-37y) and all endorsed orthostatic intolerance (6/6). Gastrointestinal symptoms (⅚), new-onset paresthesias, (3/6), and sexual dysfunction (2/6) were reported. Parasympathetic autonomic function remained stable 6-months to 1-year post-COVID-19 infection and no parasympathetic dysfunction was demonstrated in participants with new-onset dysautonomia symptoms. Postural orthostatic tachycardia was noted in half of the patients, being observed in one patient pre- SARS-CoV-2 infection and persisting post-SARS-CoV-2 infection; while new-onset postural tachycardia was observed in 1/3rd of patients. Sympathetic cholinergic (sudomotor) dysfunction was demonstrated in ALL participants. Worsened, or new-onset, sudomotor dysfunction was demonstrated in those with mild or normal sudomotor function on pre-COVID-19 autonomic testing. Sympathetic adrenergic and cholinergic dysautonomia probably account for some of the symptoms of Long COVID-19. Sudomotor dysfunction was demonstrated as consistently worsened or new-sequelae to COVID-19 infection. COVID-19 may be responsible for triggering new-onset or worsened small-fiber neuropathy in this sample, supporting previously reported studies with similar findings. However, the findings in our study are preliminary, and studies with larger sample size are needed to confirm these observations.

Preliminary findings of emotion regulation in 12-month-old infants of mothers enrolled in a randomized controlled trial assessing a nutrition+exercise intervention.

Improved offspring emotion regulation (ER) has been associated with maternal intake of single nutrients or exercise during pregnancy but has not been examined in randomized trials. We investigated the impact of a maternal nutrition+exercise intervention during pregnancy on offspring ER at 12months of age. Mothers in the Be Healthy In Pregnancy randomized controlled trial were randomly assigned to an individualized nutrition+exercise intervention plus usual care (UC) or UC alone (control group). A multimethod assessment of infant ER using parasympathetic nervous system function (high frequency heart rate variability [HF-HRV] and root mean square of successive differences [RMSSD]) as well as maternal reports of infant temperament (Infant Behavior Questionnaire- Revised short form) was completed with a subsample of infants of enrolled mothers (intervention=9, control=8). The trial was registered at www.clinicaltrials.gov (NCT01689961). We observed greater HF-HRV (M=4.63, SD=0.50, p=.04, ƞ2 p =.25) and RMSSD (M=24.25, SD=6.15, p=.04, ƞ2 p =.25) in infants of mothers in the intervention versus control group. Intervention group infants also had higher maternally rated surgency/extraversion (M=5.54, SD=0.38, p=.00, ƞ2 p =.65) and regulation/orienting (M=5.46, SD=0.52, p=.02, ƞ2 p =.81), and lower negative affectivity (M=2.70, SD=0.91, p=.03, ƞ2 p =.52). These preliminary results suggest that pregnancy nutrition+exercise interventions could improve infant ER but these findings require replication in larger, more diverse samples.

Predicting Postoperative Emergence Delirium From the Heart Rate Variability of Patients Undergoing Elective Cardiac Surgery.

Background and objective The complication of postoperative delirium is directly linked to prognosis, leading to prolonged hospital stays and an increase in mortality. Since there is no magic medicine that cures delirium, the prevention of its onset is important, and the development of simple tools that enable the early assessment of the risk is valuable. In the previous study, we hypothesized that postoperative delirium could be predicted from heart rate variability (HRV) measured by using an electrocardiogram (ECG) on the day before elective esophageal cancer surgery. HRV is calculated based on the fluctuation of RR intervals on ECG. The preoperative high-frequency (HF) power in delirium patients was significantly lower than that in non-delirium patients. The HF component is considereda reflection of parasympathetic function. In the current study, we evaluated the hypothesis that parasympathetic nerve activity is low in the resting HRV on the night before surgery in patients who go on to develop postoperative delirium. To that end, we recorded resting HRV in patients scheduled for cardiac surgery on the night before surgery. We then compared the HRV between patients with and without delirium in the postoperative intensive care unit (ICU). The Confusion Assessment Method for the ICU (CAM-ICU) was used to diagnosedelirium. Methods This was a prospective observational study involving patients undergoing elective cardiac surgery. After obtaining approval from the institutional review board, patients aged 65 years and older were enrolled in the study. The day before surgery, a Mini-Mental State Examination (MMSE) was performed. The ECG was used in patients for five minutes. All patients were transferred to the ICU after surgery, and CAM-ICU was measured every eight hours until discharge from the ICU, and positive patients were diagnosed with delirium. Results In this study, 14 patients who developed delirium and 22 patients who did notwere included in the analysis. The average MMSE score was 27.4, with no patients diagnosed with preoperative dementia. In the analysis of HRV, the HF component was significantly lower in the group with delirium compared to the group without delirium (Mann-Whitney U test, p<0.05). Conclusion Based on our findings, in patients with postoperativedelirium, the activity of parasympathetic nerves was lower than before surgery, andwe concluded that it is possible to predict the onset of postoperative delirium based on preoperative ECG measurement.

The role of strategy-use and parasympathetic functioning in maternal emotion regulation.

Research has recognized that parental emotion regulation influences whether parents respond sensitively to their children in challenging parenting situations. However, parental emotion regulation is usually assessed using questionnaires that are not about parenting, rather than through examining parents' reaction to specific parenting situations that might evoke negative emotions. This study investigates individual differences in mothers' emotion regulation during parenting, specifically examining the relation between their subjective negative emotions and observed parenting behaviors and whether this relation is moderated by cognitive (strategies to manage negative emotions) and physiological (resting baseline and reactivity of respiratory sinus arrhythmia; RSA) processes. Data of 157 mothers' self-reported negative emotions and strategy-use, their RSA, observed maternal responsiveness, and their preschool-age children's (30-60 months, 49.7% female) challenging behaviors were collected during a Wait Task, in which mothers told children to wait before opening an appealing gift. Regression analysis indicated that, after controlling for how challenging children were, mothers' level of negative emotion was not associated with observed level of maternal responsiveness. In line with hypotheses, the association was moderated by mothers' resting RSA and the extent to which they suppressed negative emotions. However, contrary to hypotheses, the association was not moderated by use of reappraisal, distraction, or rumination, or RSA reactivity. The significant findings suggest that, although mothers' subjective experiences of negative emotions are not necessarily related to less responsive parenting behaviors, the link between maternal emotions and parenting behavior may indicate differences in how mothers engage cognitive strategies as well as their physiological regulation capacity. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Decreased Cardiac Autonomic Function is Associated with Higher Exacerbation Risk and Symptom Burden in Chronic Obstructive Pulmonary Disease.

Current measures of chronic obstructive pulmonary disease (COPD) severity, including lung function, do not fully explain symptom burden, and there is a need to identify predictors of exacerbation risk and morbidity. Autonomic dysfunction may be implicated in both cardiovascular and respiratory morbidity in COPD and convey risk for exacerbations. Heart rate variability (HRV) is a marker of cardiac autonomic function that is predictive of cardiovascular health and has promise as a non-invasive COPD biomarker. The CLEAN AIR Heart study provided an opportunity to investigate the association between HRV and COPD morbidity among former smokers with moderate-severe COPD. Eighty-five participants, contributing 305 HRV measurements, underwent repeated clinical assessments over 4 study periods that included a 24-Holter monitoring assessment of HRV. HRV measures of interest were standard deviation of normal-to-normal intervals, (SDNN) (overall HRV) and root-mean-square of successive differences (RMSSD) (parasympathetic function). Exacerbation risk was assessed using negative binomial models, and mixed-effects models analyzed associations between HRV and symptoms. Decreases in SDNN (incidence rate ratio [IRR]1.40; 95% confidence interval [CI] 1.13 to1.74) and RMSSD (IRR 1.60; 95% CI 1.07 to 2.37) were associated with severe exacerbation risk. Decreases in SDNN were associated with higher St George's Respiratory Questionnaire scores, COPD Assessment Test scores, and chronic bronchitis symptoms. Findings demonstrate that HRV is associated with COPD symptom burden and exacerbation risk. HRV may represent an important biomarker with the potential to identify high-risk COPD populations.

Correlation of Pupil Cycle Time and Postural Hypotension as a Marker for Diabetic Neuropathy

Introduction: Diabetic Neuropathy (DN) can involve autonomic nervous system like cardiovascular system and pupillary reflex. Cardiovascular DN can be measured by estimating the change in Blood Pressure (BP) based on position. Ocular DN can be evaluated by using Pupil Cycle Time (PCT), which is an early diagnostic tool to estimate ocular DN. It is a simple way to measure autonomic reflex activity and is a specific test to study parasympathetic function. Aim: To assess the correlation of effects of postural hypotension and PCT on persistent diabetes. Materials and Methods: The prospective cross-sectional study was conducted in Ophthalmology Out Patient Department (OPD) at KS Hegde Medical Academy, Mangalore, Karnataka, India, from January 1st 2019 to December 31st 2019. The study included 60 male patients between the age group of 40-60 years which were divided into two groups of 30 diabetics (Random Blood Sugar (RBS) &gt;200 mg/dL, Fasting Blood Sugar (FBS) &gt;126 mg/dL and Glycated Haemoglobin (HbA1c) &gt;6.5%) and 30 non diabetics. The blood pressure of all the patients were recorded using a sphygmomanometer in sitting and standing positions. PCT was measured in both eyes using Haggstreittype of slit lamp after the subject was seated in a dimly lit room after dark adaptation for 15 minutes. Results: The mean age of patients in the diabetic group was 54±3.2 years and the non diabetic group was 52±2.7 years. The mean HbA1c of diabetics was 6.9±0.8%. The mean BP among diabetics in standing position was 133.86±29.34 mmHg systolic and 87.4±16.72 mmHg diastolic whereas in sitting position, it was 141.66±28.17 mmHg systolic and 85.26±13.39 mmHg diastolic. The mean BP among non diabetics in standing position was 129.46±24.84 mmHg systolic and 83.46±13.52 mmHg diastolic whereas in sitting position, it was 132.06±26.48 mmHg systolic and 81.26±11.45 mmHg diastolic. The mean PCT-I and PCT-II in diabetics was 1000.52±187.73 and 1006.09±199.45, respectively. The systolic and diastolic BP, both during sitting and standing postures, in diabetic patients were high. The mean PCT-I and PCT-II in non diabetics was 853.23±181.54 and 880.17±192.72, respectively. The PCT-I and PCT-II were found to be significantly high in diabetic patients as compared to controls. The PCT-I and PCT-II negatively correlated with both diastolic and systolic blood pressure in sitting and standing postures. Conclusion: Prolongation of PCT in diabetics correlates significantly with evidence of autonomic neuropathy obtained from testing of postural BP variations. Patients whose cardiovascular reflexes are very abnormal tend to have pupils which cycle slowly.

Heart rate recovery at 1st min after graded exercise an indicator of parasympathetic function in healthy obese young adults

Heart rate recovery at 1st min after graded exercise an indicator of parasympathetic function in healthy obese young adults

Vagal cross-sectional area correlates with parasympathetic dysfunction in Parkinson's disease.

The aim of this prospective study was to investigate autonomic function in Parkinson's disease with a multidimensional approach including clinical evaluation tools, head-up tilt test and morphological studies of the vagus nerve. Head-up tilt test parameters including high frequency power of the heart frequency interval, the ratio of low frequency power of the distance between two consecutive R waves in electrocardiogram (RR interval) to the high frequency and low frequency power of systolic blood pressure were used to evaluate parasympathetic, cardiac sympathetic and vasomotor sympathetic functions, respectively, in 80 patients with Parkinson's disease. We examined the cross-sectional area of the vagus nerves bilaterally using nerve ultrasound and compared mean values with a control group of healthy subjects (n = 40) as well as patients with chronic inflammatory demyelinating polyneuropathy (n = 76). The cross-sectional area of right/left vagus nerve of Parkinson's patients was significantly lower compared to the right/left vagus nerve of the control group and of chronic demyelinating polyneuropathy patients. Furthermore, the cross-sectional area of the right vagus nerve was significantly larger from the one of the left vagus nerve for all groups. Based on tilt test, 43 patients (disease duration 7 ± 5, age at evaluation 71 ± 9, Hoehn and Yahr score 2.8 ± 8) were diagnosed with autonomic dysfunction (orthostatic hypertension n = 11, chronotropic incompetence n = 31, postural orthostatic tachycardia syndrome n = 1). Patients with orthostatic hypotension showed significantly higher Unified Parkinson's Disease Rating Scale-III values than those with chronotropic incompetence. The cross-sectional area of the vagus nerve correlated inversely with heart rate in rest and supine position and positively with tilt test parameters representing parasympathetic modulation through vagal activity [high frequency power of the distance between two consecutive R waves in electrocardiogram (RR interval)] at rest. We demonstrate for the first time that morphological characteristics of the vagus nerve correlate with parameters of parasympathetic function from the spectral analysis of cardiovascular parameters in tilt test for Parkinson's patients. This correlation reveals the impact of the atrophy of vagal atrophy for autonomic function in Parkinson's disease. Nerve ultrasound of the vagus nerve could potentially be used as an adjunct to tilt table examination to diagnose autonomic dysfunction.

PHYSIOLOGICAL DYSREGULATION AS A PREDICTOR OF COGNITIVE DECLINE

Abstract Preclinical indicators of disease such as inflammation, cortisol and glucose dysregulation, and multisystem dysregulation (allostatic load) are related to individual differences in the level of cognitive functioning across adulthood. This study examined whether individual biological systems and allostatic load are related to differential patterns of change in cognitive functioning over 9 years. Data are from the Midlife in the United States (MIDUS) study second (biomarker and cognitive) and third waves (cognitive). The sample includes 863 men and women who ranged in age from 35 to 85 when the data were first collected. MIDUS biomarkers include a comprehensive range of biological and anthropometric measurements reflecting cardiovascular functioning, glucose metabolism, lipid metabolism, inflammation, HPA axis function, as well as sympathetic and parasympathetic nervous system function. Summary indices of dysregulation in each of these major systems as well as an overall index of multi-system dysregulation, or allostatic load were examined in relation to 9-year changes in episodic memory and executive functioning from the Brief Test of Adult Cognition by Telephone. Regression analyses, controlling for preexisting diseases and medications, showed that higher allostatic load was associated with decreased executive functioning over time for those who started out with higher cognitive performance at baseline, after adjusting for age, gender, race, English language, education, neurological conditions, medication use and smoking. Identifying biomarkers as antecedents of cognitive changes in midlife and old age, can potentially aid in the early detection of cognitive impairments and increase the possibilities for preventive interventions.