Sympathetic dysfunction as an early indicator of autonomic involvement in Parkinson's disease.

PURPOSE: The specific characteristics of autonomic involvement in patients with early Parkinson's disease (PD) are unclear. This study aimed to evaluate the characteristics of autonomic dysfunction in drug-naïve patients with early-stage PD without orthostatic hypotension (OH) by analyzing Valsalva maneuver (VM) parameters. METHODS: We retrospectively analyzed drug-naïve patients without orthostatic hypotension (n = 61) and controls (n = 20). The patients were subcategorized into early PD (n = 35) and mid-PD (n = 26) groups on the basis of the Hoehn and Yahr staging. VM parameters, including changes in systolic blood pressure at late phase 2 (∆SBPVM2), ∆HRVM3, Valsalva ratio (VR), pressure recovery time, adrenergic baroreflex sensitivity, and vagal baroreflex sensitivity, were assessed. RESULTS: In the early PD group, ∆SBPVM2, a marker of sympathetic function, was significantly lower compared with that in controls (risk ratio = 0.95, P = 0.027). Receiver operating characteristic (ROC) curve analysis showed an optimal cut-off value of -10 mmHg for ∆SBPVM2 [P = 0.002, area under the curve (AUC): 0.737]. VR exhibited an inverse relationship with Unified Parkinson's Disease Rating Scale Part 3 scores in the multivariable regression analysis (VR: P = 0.038, ß = -28.61), whereas age showed a positive relationship (age: P = 0.027, ß = 0.35). CONCLUSION: The ∆BPVM2 parameter of the VM may help detect autonomic nervous system involvement in early-PD without OH. Our results suggest that sympathetic dysfunction is an early manifestation of autonomic dysfunction in patients with PD.

Concordance Analysis of the Pressure Chamber and Tubomanometer According to Estève for the Determination of Eustachian Tube Opening Pressure.

INTRODUCTION: For the diagnosis of Eustachian tube dysfunction (ETD), clinical procedures such as tympanometry, micro-otoscopy, and maneuvers according to Toynbee and Valsalva only allow an indirect assessment for the moment. With a prevalence of up to 5%, the selection of patients with ETD and its subtypes is clinically relevant. Dynamic methods of Eustachian tube function assessment include a hypo/hyperbaric pressure chamber and Estève's tubomanometer (TMM). One method of assessing ETD is the evaluation of Eustachian tube opening pressure (ETOP). MATERIAL AND METHODS: We performed a concordance analysis between pressure chamber and TMM to determine ETOP. For this purpose, we analyzed the measurements of both methods from 28 healthy subjects using Bland-Altman plots, regression according to Passing-Bablok and Lin's concordance correlations coefficient. The maximum tolerated clinical deviation of measured values was set at 10%. RESULTS: A maximum of 53 measurements of ETOP between pressure chamber and TMM were compared. Mean ETOP for TMM was 28.7 hPa, passive opening was 32 hPa, Toynbee maneuver was 28.4 hPa, and Valsalva maneuver was 54.6 hPa. Concordance analysis revealed following results: passive opening versus TMM: Bland-Altman mean difference 3.3 hPa, limits of agreement ±31.8 hPa; Passing-Bablok regression y = 0.67 x + 9.36; Lin's rccc = 0.18. Toynbee versus TMM: Bland-Altman mean difference 0.7 hPa, limits of agreement ±35.8 hPa; Passing-Bablok regression y = 0.47x + 14.03; Lin's rccc = 0.14. Valsalva versus TMM: Bland-Altman mean difference 24.2 hPa, limits of agreement ±117.5 hPa; Passing-Bablok regression y = 0.17x + 25.12; Lin's rccc = 0.18. CONCLUSION: Estève's tubomanometer and pressure chamber measurements of ETOP are not concordant. The two methods cannot be interchanged without reservation.

Decoding cardiac reinnervation from cardiac autonomic markers: A mathematical model approach.

BACKGROUND: Although cardiac autonomic markers (CAMs) are commonly used to assess cardiac reinnervation in heart-transplant patients, their relationship to the degree of sympathetic and vagal cardiac reinnervation is not well understood yet. To study this relationship, we applied a mathematical model of the cardiovascular system and its autonomic control. METHODS: By simulating varying levels of sympathetic and vagal efferent sinoatrial reinnervation, we analyzed the induced changes in CAMs including resting heart rate (HR), bradycardic and tachycardic HR response to Valsalva maneuver, root mean square of successive differences between normal heartbeats (RMSSD), low-frequency (LF), high-frequency (HF), and total spectral power (TSP). RESULTS: For assessment of vagal cardiac reinnervation levels >20%, resting HR (ρ = 0.99, p < 0.05), RMSSD (ρ = 0.97, p < 0.05), and TSP (ρ = 0.96, p < 0.05) may be equally suitable as HF-power (ρ = 0.97, p < 0.05). To assess sympathetic reinnervation, LF/HF ratio (ρ = 0.87, p < 0.05) and tachycardic response to Valsalva maneuver (ρ = 0.9, p < 0.05) may be more suitable than LF-power (ρ = 0.77, p < 0.05). CONCLUSIONS: Our model reports mechanistic relationships between CAMs and levels of efferent autonomic sinoatrial reinnervation. The results indicate differences in the suitability of these markers to assess vagal and sympathetic reinnervation. Although our analysis is purely conceptual, the developed model can help to gain important insights into the genesis of CAMs and their relationship to efferent sinoatrial reinnervation and, thus, provide indications for clinical study evaluation.

A Pilot Observational Cohort Study to Investigate the Effect of Valsalva Maneuver on Internal Jugular Venous Diameter.

Valsalva maneuver (VM) is a technique widely used for acute elevation of blood pressure in humans. It has potential applications in cardiac health prediction and is also a diagnostic tool in cardiovascular, neurology and ENT screening. The jugular venous (JV) diameter increases during the VM procedure and hence it has been widely used to aid central venous catheterization in medical units. In this pilot study, we have quantified the variation in JV diameter response to VM across young and middle-aged populations. The study was conducted on a cohort of 16 males and 11 females, where the JV diameter in baseline, during and post VM intervention were acquired using a B-mode imaging system. The JV diameter measurements were within the ranges specified in earlier literature. The beat-to-beat variability in baseline diameter measurements was found to be between 8% to 20%. In younger population, the average maximum JV diameter during baseline was found to be 9.25 ± 2.61 mm and in middle-aged population it was 12.49 ± 2.65 mm. The average maximum JV diameter in young and middle-aged population during VM was 11.66 ± 2.74 mm and 16.73 ± 3.28 mm respectively. The study findings suggested a statistically significant variation (p < 0.05) between the JV diameter responses from young and middle-aged populations. The JV distensibility decreased significantly during VM in younger cohort (-35%) in comparison with the minimal changes observed in middle-aged population. The study demonstrates the variation in JV diameter and distensibility to VM in young and middle-aged populations.Clinical Relevance- This pilot study reveals the variations in JV diameter in response to VM intervention in young and middle-aged groups which has potential utility in assessing age dependent changes in vasculature.

Forced inspiratory suction and swallow tool (FISST): an automation of Valsalva maneuver variants for therapeutic interventions.

INTRODUCTION: The Valsalva maneuver and its modifications have been utilized across several conditions in medicine; however, there have been difficulties in its application. Thus, at the University of Texas Health Science Center in San Antonio, we designed and patented an affordable and accessible device that mimics Valsalva called "Forced Inspiratory Suction and Swallow Tool (FISST). AREAS COVERED: In this review, we discuss the premise for the design of FISST, based on applications of the law of conservation energy, the continuity equation, and Bernoulli's principle. We then detail the mechanism by which FISST stimulates hiccup cessation by increasing negative inspiratory pressure when drinking through the apparatus, causing diaphragmatic contraction and disruption of the hiccup reflex. We then detail the efficacy and future applications of FISST in addressing other pathologies. EXPERT OPINION: FISST has been used to address hiccups by utilizing its reverse-Valsalva effect to increase parasympathetic stimulation by increasing vagal tone. In a prospective study that we conducted on a cohort of 249 hiccup subjects worldwide, this tool achieved 92% effectiveness. Additionally, several cases, including a published case report, have found FISST successful in terminating supraventricular tachycardias (SVT). FISST may be further utilized in diagnosing or addressing various upper airway pathologies and should be explored further.

Autonomic dysfunction after mild acute ischemic stroke and six months after: a prospective observational cohort study.

INTRODUCTION: Autonomic dysfunction is prevalent in ischemic stroke patients and associated with a worse clinical outcome. We aimed to evaluate autonomic dysfunction over time and the tolerability of the head-up tilt table test in an acute stroke setting to optimize patient care. PATIENTS AND METHOD: In a prospective observational cohort study, patients were consecutively recruited from an acute stroke unit. The patients underwent heart rate and blood pressure analysis during the Valsalva maneuver, deep breathing, active standing, and head-up tilt table test if active standing was tolerated. In addition, heart rate variability and catecholamines were measured. All tests were performed within seven days after index ischemic stroke and repeated at six months follow-up. RESULTS: The cohort was comprised of 91 acute stroke patients, mean (SD) age 66 (11) years, median (IQR) initial National Institute of Health Stroke Scale 2 (1-4) and modified Ranking Scale 2 (1-3). The head-up tilt table test revealed 7 patients (10%) with orthostatic hypotension. The examination was terminated before it was completed in 15%, but none developed neurological symptoms. In the acute state the prevalence of autonomic dysfunction varied between 10-100% depending on the test. No changes were found in presence and severity of autonomic dysfunction over time. CONCLUSION: In this cohort study of patients with mild stroke, autonomic dysfunction was highly prevalent and persisted six months after index stroke. Head-up tilt table test may be used in patients who tolerate active standing. Autonomic dysfunction should be recognized and handled in the early phase after stroke.

Altered baroreflex sensitivity at rest and during Valsalva maneuver in healthy male offspring of hypertensive patients.

INTRODUCTION: A family history of hypertension puts young adults at a higher risk of developing hypertension, that too, at an earlier age than their parents. Recent studies suggest that the baroreflex mechanism, which takes care of the short-term regulation of blood pressure (BP), also plays a role in the long-term regulation of BP. Studies have reported decreased baroreflex sensitivity (BRS) in hypertensives. Reduced BRS is shown to herald the future occurrence of cardiovascular diseases (CVD) and helps in risk stratification AIM: To assess BRS at rest and during the Valsalva maneuver among apparently healthy male offspring (age 18-35 years) of hypertensive patients. METHODS: We recruited 37 participants whose parents (either/both) were hypertensive in the study group and whose parents (both) were not hypertensive in the control group. We measured basic anthropometric parameters (height, weight, waist circumference), cardiovascular parameters (heart rate and BP), short-term heart rate variability, and BRS (at rest and during Valsalva). RESULTS: We found that BRS at rest and BRS during the Valsalva maneuver were reduced among healthy male offspring of hypertensive parents than in healthy male offspring of non-hypertensive parents. Further, HRV indices and Valsalva ratio showed a sympathovagal imbalance in the form of decreased vagal and increased sympathetic activity. CONCLUSION: The reduced BRS and sympathovagal imbalance in male offspring of hypertensive parents reveal the early risk of developing hypertension in the future.

Use of Valsalva Maneuver to Detect Late-Onset Delayed Orthostatic Hypotension.

BACKGROUND: Standard autonomic testing includes a 10-minute head-up tilt table test to detect orthostatic hypotension. Although this test can detect delayed orthostatic hypotension (dOH) between 3 and 10 minutes of standing, it cannot detect late-onset dOH after 10 minutes of standing. METHODS: To determine whether Valsalva maneuver responses can identify patients who would require prolonged head-up tilt table test to diagnose late-onset dOH; patients with immediate orthostatic hypotension (onset <3 minutes; n=176), early-onset dOH (onset between 3 and 10 minutes; n=68), and late-onset dOH (onset >10 minutes; n=32) were retrospectively compared with controls (n=114) with normal head-up tilt table test and composite autonomic scoring scale score of 0. RESULTS: Changes in baseline systolic blood pressure at late phase 2 (∆SBPVM2), heart rate difference between baseline and phase 3 (∆HRVM3), and Valsalva ratio were lower and pressure recovery time (PRT) at phase 4 was longer in late-onset dOH patients than in controls. Differences in PRT and ∆HRVM3 remained significant after correcting for age. A PRT ≥2.14 s and ∆HRVM3 ≤15 bpm distinguished late-onset dOH from age- and sex-matched controls. Patients with longer PRT (relative risk ratio, 2.189 [1.579-3.036]) and lower ∆HRVM3 (relative risk ratio, 0.897 [0.847-0.951]) were more likely to have late-onset dOH. Patients with longer PRT (relative risk ratio, 1.075 [1.012-1.133]) were more likely to have early-onset than late-onset dOH. CONCLUSIONS: Long PRT and short ∆HRVM3 can help to identify patients who require prolonged head-up tilt table test to diagnose late-onset dOH.

Clinical assessment of pelvic organ prolapse by consecutive cough maneuver.

INTRODUCTION AND HYPOTHESIS: Staging of pelvic organ prolapse (POP) is important in clinical practice and research. Pelvic organ descent on Valsalva can be confounded by levator co-activation, which may be avoided by assessment on coughing. We evaluated the performance of a three consecutive coughs maneuver in the assessment of POP compared with standardised 6-second Valsalva. METHODS: This was a retrospective observational study carried out in women attending a tertiary urogynaecological service in 2017-2019. Patients underwent a standardised interview and clinical examination. Clinical assessment was performed twice, with both 6-s Valsalva and three consecutive coughs performed in random order. Main outcomes were Ba, C and Bp as defined by Pelvic Organ Prolapse-Quantification (POP-Q). Association between coordinates and prolapse symptoms was investigated with receiver-operating characteristic (ROC) statistics. RESULTS: Datasets of 855 women were analysed. POP symptoms were reported by 447 patients (52%) with a mean bother of 6.1 (SD 3.0). On clinical assessment, relevant prolapse was found in 716 (84%) patients on Valsalva and in 730 (85%) on coughing (p=0.109). Clinically relevant prolapse in the apical compartment was more likely to be detected on Valsalva (p<0.0001). Mean POP-Q measurements were not significantly different between maneuvers, except for Ba (p=0.004). ROC curve analysis yielded an area under the curve of 0.74 (95% CI, 0.70-0.77) for maximum POP-Q stage on Valsalva and 0.72 (95% CI, 0.69-0.75) after three consecutive coughs, with a similar performance of both maneuvers in predicting prolapse symptoms (p=0.95). CONCLUSIONS: Clinical assessment of POP by consecutive coughing seems complementary to standardised Valsalva, especially if Valsalva performance is poor.

Effects of intensity and training on cardiovascular responses to the Valsalva maneouvre.

OBJECTIVES: To establish the effect of intensity of effort during Valsalva's manoeuvre (VM) on blood pressure and heart rate responses. METHODS: Fourteen participants consisting of eight powerlifters and six controls completed four 15-s VMs at 30 and 50% maximum expiratory pressure. Expiratory pressure (EP), systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were recorded continuously during manoeuvres and response amplitudes were related to well-established phases (I-IV). RESULTS: For all participants, SBP and DBP responses during Phase I were significantly higher at 50% EPmax than 30% EPmax. Phase II responses were significantly higher at 50% EPmax than 30% EPmax for HR (39.9 ± 24.3 vs. 24.5 ± 12.5 bpm), SBP (43.6 ± 24.6 vs. 35.3 ± 18.3 mm Hg) and DBP (26.7 ± 7.1 vs. 21.1 ± 7.4 mm Hg). For Phase IV, only the HR response was affected significantly by intensity. These intensity-dependent effects were similar between powerlifters and controls. Powerlifters had significantly greater Phase II responses (HR, SBP and DBP), but in the whole group these cardiovascular responses were also significantly correlated with expiratory pressure (mm Hg) at 30% EPmax (r=0.59-0.84) and 50% EPmax (r=0.53-0.82) which was higher in powerlifters than controls. CONCLUSIONS: This study demonstrates that heart rate and blood pressure responses during Phase II are affected by the relative intensity of VM, whereas during Phase IV only heart rate is affected. The higher Phase II responses in powerlifters can be attributed to the higher expiratory pressures they developed.

Differences in the cardiovascular hemodynamic response between the Valsalva and Reverse Valsalva Maneuvers in healthy subjects.

BACKGROUND: The Valsalva Maneuver (VM) is the first-line treatment for paroxysmal supraventricular tachycardia, but a recent, novel, and efficient tool to restore sinus rhythm has been described, i.e., the Reverse Valsalva (RV). This study aims to compare changes in cardiovascular hemodynamics and autonomic system activity (ANS) based on heart rate variability (HRV) analysis during both maneuvers. METHODS: Fifteen healthy participants performed the VM and RV maneuvers three times in a sitting position for durations of 15 s and 10 s, respectively. Blood pressure (BP) and heart rate (HR) were continuously monitored before, during and after the tests. Autonomic system activity was evaluated using frequency-domain analysis of HRV. RESULTS: The decrease in HR from baseline to the lowest values, expressed as a ratio, was similar during both maneuvers (0.81 during the RV vs. 0.79 during the VM, p = 0.27). However, the final lowest HR in response to the RV was higher than that in response to the VM, 70/min vs. 59/min (p <0.001). The activation of the autonomic nervous system during the most bradycardic phase of the RV (phase II) and VM (phase IV) showed that the total power of HRV was less prominent during the RV than during the VM (p <0.012), with similar levels of parasympathetic activation. CONCLUSIONS: Our results showed less HR slowdown during the RV than during the VM. The changes in HRV parameters during both procedures in particular phases of the RV and VM suggest that the autonomic nervous system is activated alternately, so these tests can be used complementarily in a clinical setting with different results.

"Forced inspiratory suction and swallow tool" a novel instrument to convert paroxysmal supraventricular tachycardia (SVT) to sinus rhythm, a case report and introduction of the device.

Paroxysmal Supraventricular Tachycardia (SVT) is an arrhythmia with sudden onset and termination, characterized by a fast heart rate and a narrow QRS complex. There are several remedies that have been described to convert the SVT, such as the Valsalva maneuver, holding the breath for a few seconds, or putting cold water on the face. Here we are presenting a case of SVT, which we converted to sinus rhythm instantly by using a novel tool that has been designed and patented at the University of Texas. This device is named "Forced Inspiratory Suction and Swallow Tool" (FISST) and is branded as "HiccAway," which is primarily designed to stop hiccups and is available as an over-the-counter tool. It works by drinking water forcibly through a pressure valve, and it follows "Bernoulli's Principle": applications of the law of conservation energy.

Preferential impairment of parasympathetic autonomic function in type 2 diabetes.

OBJECTIVE: Cardiovascular autonomic neuropathy is a known complication in type 2 diabetes (T2D). However, the extent of sympathetic dysfunction and its relation to blood pressure (BP) dysregulation is insufficiently studied. We therefore assessed the cardiovascular sympathetic function using a standardized autonomic test-battery. RESEARCH DESIGN AND METHODS: Forty T2D patients (mean age and duration of diabetes ±SD, 65.5 ± 7.3 and 9.5 ± 4.2 years) and 40 age- and gender-matched controls were examined through autonomic testing, assessing cardiovascular responses to deep breathing, Valsalva maneuver and tilt-table testing. Additionally, 24-hour oscillometric BP and self-reported autonomic symptoms on COMPASS-31 questionnaire was recorded. RESULTS: Patients with T2D had reduced parasympathetic activity with reduced deep breathing inspiratory:expiratory-ratio (median [IQR] T2D 1.11 [1.08-1.18] vs. controls 1.18 [1.11-1.25] (p = 0.01)), and reduced heart rate variability (p < 0.05). We found no differences in cardiovascular sympathetic function measured through BP responses during the Valsalva maneuver (p > 0.05). 24-hour-BP detected reduced night-time systolic BP drop in T2D (9.8 % ± 8.8 vs. controls 15.8 % ± 7.7 (p < 0.01)) with more patients having reverse dipping. Patients with T2D reported more symptoms of orthostatic intolerance on the COMPASS-31 (p = 0.04). CONCLUSIONS: Patients with T2D showed reduced parasympathetic activity but preserved short-term cardiovascular sympathetic function, compared to controls, indicating autonomic dysfunction with predominantly parasympathetic impairment. Despite this, T2D patients reported more symptoms of orthostatic intolerance in COMPASS-31 and had reduced nocturnal BP dipping, indicating that these are not a consequence of cardiovascular sympathetic dysfunction.

Baroreflex sensitivity derived from the Valsalva manoeuvre: A physiological protective factor for anxiety induced by breathing CO2-enriched air.

This study aimed to determine the capacity of baroreflex sensitivity, derived from the Valsalva manoeuvre (BRS_v), to predict state anxiety induced by a biological stressor (CO2 inhalation). Healthy adults (n = 50) breathed 7.5 % CO2-enriched air for 8 min, preceded and followed by breathing medical air for 5 min. State anxiety was evaluated with a visual analogue scale. Anxiety sensitivity (Anxiety Sensitivity Index-3; ASI-3) and trait anxiety (Trait form of the State-Trait Anxiety Inventory; STAI_T) served as cognitive-affective predictors. BRS_v was adopted as a physiological predictor. Multiple regression analysis revealed that BRS_v predicted lower anxiety during CO2 exposure, and attenuated the effect of ASI-3 in increasing anxiety. No significant effects were found for STAI_T. This is the first study to identify baroreflex sensitivity as a strong protective physiological factor for anxiety beyond the effect of anxiety sensitivity.

Pelvic floor muscle dysfunction at 3D transperineal ultrasound in maternal exposure to gestational diabetes mellitus: A prospective cohort study during pregnancy.

AIM: This study aimed to assess, for the first time, the dynamic morphometry of pelvic floor muscles (PFM) using three-dimensional transperineal ultrasound (3D-TPUS) and its progression at two-time points of gestation between women with and without gestational diabetes mellitus (GDM), and whether the PFM dysfunction is connected to GDM. METHODS: The study comprised 83 consecutive pregnant women with (n = 38) and without (n = 45) GDM screened at 24-30 and 38-40 weeks of gestation. 3D-TPUS and a mobility test were used to quantify PFM dynamic morphometry during maximum contraction and the Valsalva maneuver. RESULTS: When compared to the control group, GDM women had no significant variations in all levator hiatal dimensions at 24-30 weeks of gestation. Meanwhile, women with GDM experienced an increase in levator hiatal area (LHa) (p < 0.000) during PFM contraction and enlargement in LHa (p < 0.001) during Valsalva maneuver (p = 0.010) at 38-40 weeks of gestation. As a result, the mobility index among GDM women had a lower value (p = 0.000). The dynamic morphometry development of PFM in GDM women at two stages during pregnancy revealed a substantial decrease (p = 0.000) in all LHa dimensions of contraction, distension, and mobility. CONCLUSIONS: Using 3D-TPUS, we found that GDM women had a specific pattern of PFM functional changes in the third trimester of pregnancy. These initial findings revealed alterations in PFM functionality, such as decreased contractility, distensibility, or mobility. This dysfunctional PFM could contribute to the long-term development of pelvic floor dysfunction years after a GDM pregnancy.

The correlation between levator ani co-activation and fetal head regression on maternal pushing at term.

OBJECTIVE: To assess the correlation between fetal head regression and levator ani muscle (LAM) co-activation under Valsalva maneuver. STUDY DESIGN: This study was a secondary analysis of a prospective cohort study on the association between the angle of progression (AoP) and labor outcome. We scanned a group of nulliparous women at term before the onset of labor at rest and under maximum Valsalva maneuver. In addition to the previously calculated AoP, in the present study, we measured the anteroposterior diameter of LAM hiatus (APD) on each ultrasound image. LAM co-activation was defined as APD at Valsalva less than that at rest, whereas fetal head regression was defined as AoP at Valsalva less than that at rest. We calculated the correlation between the two phenomena. Finally, we examined various labor outcomes according to the presence, absence, or co-existence of these two phenomena. RESULTS: We included 469 women. A total of 129 (27.5%) women presented LAM co-activation while 50 (10.7%) showed head regression. Only 15 (3.2%) women showed simultaneous head regression and LAM co-activation. Women with coexisting LAM co-activation and head regression had the narrowest AoP at Valsalva in comparison with other study groups (p < .001). In addition, they had the highest risk of Cesarean delivery (40%) and longest first, second, and active second stage durations, although none of these reached statistical significance. CONCLUSION: In nulliparous women at term before the onset of labor fetal head regression and LAM co-activation at Valsalva are two distinct phenomena that uncommonly coexist.

Test-retest reliability of the Valsalva maneuver in spinal cord injury.

Objective: To determine the test-retest reliability of quantitative and qualitative baroreflex sensitivity (BRS) parameters derived from the Valsalva maneuver (VM) in individuals with traumatic cervical SCI.Design: Test-retest reliability.Setting: Tertiary rehabilitation center.Participants: Fourteen participants with cervical SCI (ranging from C3-C8 neurological level).Outcome Measurements: Beat-to-beat systolic blood pressure (SBP) traces (finger photoplethysmography) were obtained during a 15-second forced expiration at two time points (7.6 ± 2.9 days between sessions) to assess VM reliability. Test-retest reliability of BRS metrics from derived from the VM (Valsalva ratio; VR, pressure recovery time; PRT, vagal baroreflex sensitivity; BRSv, adrenergic baroreflex sensitivity; BRSa1, and total recovery; TR) were assessed by intra-class correlation coefficient (ICC, with 95% confidence interval; CI) and by qualitative reproducibility (V, N, or M pattern).Results: ICCs for quantitative parameters were (CI): VR = 0.894 (0.703-0.965), TR = 0.927 (0.789-0.976), BRSa1 = 0.561 (0.149-0.911), PRT = 0.728 (0.343-0.904), BRSv = 0.243 (-0.309-0.673). Qualitatively, 12 subjects (85.7%) demonstrated reproducible VM patterns at both time points (3 "M" pattern, 8 "V" pattern and one "N" pattern).Conclusion: VR (a measure of cardiovagal function) and TR (a measure of sympathetic adrenergic function) are reliable quantitative parameters that can be derived from SBP response to VM in participants with SCI. Qualitative waveform analysis was reproducible in 12/14 participants. This provides the foundational evidence required to pursue further validity testing to establish a role for VM in the assessment of autonomic functions in SCI.

The Association Between Cardiovascular Autonomic Function and Changes in Kidney and Myocardial Function in Type 2 Diabetes and Healthy Controls.

Background: The mechanisms linking cardiovascular autonomic neuropathy, diabetic kidney disease and cardiovascular mortality in type 2 diabetes are widely unknown. We investigated the relationship between baseline cardiovascular autonomic function and changes in kidney and myocardial function over six years in patients with type 2 diabetes and healthy controls. Methods: Post-hoc analysis of a cohort study in 24 patients with type 2 diabetes and 18 healthy controls. Baseline determinants were cardiovascular autonomic reflex tests (heart rate response to: standing (30:15); deep breathing (E:I); and the Valsalva test) and time- and frequency-domain heart rate variability indices. Outcomes were changes in estimated glomerular filtration rate (eGFR), albuminuria, myocardial flow reserve (MFR) measured by cardiac 82Rb Positron emission tomography computed tomography (PET/CT), and coronary artery calcium score (CACS). Results: Mean age at inclusion was 61 ± 10 years and 36% were female. Mean follow up time was 6 ± 0 years. A lower response in heart rate to the Valsalva test (corresponding to weaker autonomic function) was associated with a larger decline in eGFR (p=0.04), but not significantly after adjustment for sex, baseline age, smoking status, systolic blood pressure, heart rate, HbA1c, body mass index and baseline eGFR (p=0.12). A higher baseline response in heart rate to standing (30:15) was associated with a larger decline in myocardial flow reserve in the unadjusted analysis (p=0.02) and after adjustment (p=0.02). A higher response in heart rate to the Valsalva maneuver was associated with a larger increase in CACS (p = 0.02), but the association became insignificant after adjustment (p = 0.16). Conclusion: A lower response in heart rate to the Valsalva test was associated with a larger decline in kidney function, indicating that autonomic dysfunction may predict future loss of kidney function. However, we did not find any association between lower values in cardiovascular autonomic function at baseline and a worsening in albuminuria, myocardial function, or atherosclerotic burden.

Auxiliary Tests of Autonomic Functions.

SUMMARY: The autonomic nervous system is a complex neural network that controls several organ systems. Its assessment includes a detailed history of autonomic functions, clinical examination, and autonomic tests. Most widely used is a battery of tests that assess cardiovascular reflex autonomic and sudomotor tests, which include deep breathing (assesses parasympathetic function), Valsalva maneuver, tilt test (both assess parasympathetic and adrenergic functions), and sudomotor testing for the evaluation of postganglionic sudomotor fibers. These basic tests represent a foundation of autonomic testing. Nevertheless, the autonomic nervous system also controls organ systems not directly assessed by basic tests. This review describes a number of auxiliary autonomic tests that can be used in addition to basic autonomic tests or can be used independently to explore particular autonomic functions or to answer a specific clinical question. The auxiliary tests described in this review evaluate cardiovascular, thermoregulatory, gastrointestinal, genitourinary, eye, and exocrine functions. These tests are cold pressor test, sustained handgrip maneuver, reverse tilt test, venoarteriolar reflex, laser Doppler flare imaging, microneurography, neck suction, lower body negative pressure, venous occlusion plethysmography, pharmacologic assessment of postganglionic sympathetic outflow, plasma norepinephrine, sympathetic skin response, video cinefluoroscopic swallowing test, esophageal manometry test, small bowel manometry test, wireless motility capsule test, urodynamic studies, penile plethysmography, intracavernosal papaverine injection, infrared video pupillography, corneal confocal microscopy, pupillary response to dilute pilocarpine and hydroxyamphetamine, Schirmer test, tear osmolarity test, and salivary secretion test. The protocol of each test is described in detail. This review can be used as a quick reference for the auxiliary autonomic tests.