Clinical Autonomic Research最新文献

Purpose: To explore the relationship between primary focal hyperhidrosis (PFH) and generalized autonomic dysfunction, we assessed autonomic symptom burden using a comprehensive and validated measure of autonomic symptoms.

Methods: In this case-control study, we compared 132 patients with PFH with 74 matched healthy controls. Autonomic symptoms were assessed using the Composite Autonomic Symptom Score-31 (COMPASS-31) questionnaire. Propensity score matching minimized confounding. Mann-Whitney U tests compared COMPASS-31 scores between groups. A sensitivity analysis using multivariate linear regression accounted for specific hyperhidrosis sites and demographic factors.

Results: PFH cases demonstrated significantly higher median COMPASS-31 scores compared to controls (18.7 [IQR 7.7-34.8] vs. 11.2 [IQR 3.5-19.3], p < 0.001). Significant differences were observed in orthostatic (2.0 [0-20] vs. 0 [0-12], p = 0.028), vasomotor (0 [0-0] vs. 0 [0-0], p = 0.005; 24.2% vs. 9.5% non-zero scores, respectively), secretomotor (3.2 [2.1-8.6] vs. 0 [0-3.8], p < 0.001), and gastrointestinal (5.4 [1.8-8] vs. 1.8 [0.9-5.4], p = 0.004) domains. Sensitivity analysis confirmed PFH status as a significant predictor of higher COMPASS-31 scores (additional 7.5 points on average, 95% CI 1.6-13.4, p = 0.012) after adjusting for demographic factors and hyperhidrosis sites. Craniofacial and truncal hyperhidrosis were associated with higher autonomic symptom burden.

Conclusion: PFH is associated with a broader spectrum of autonomic symptoms beyond localized sweating, establishing a link to more generalized autonomic dysfunction. These findings underscore the need for a comprehensive approach to evaluating and managing patients with PFH.

Purpose: Autonomic dysfunction, including early cardiovascular parasympathetic involvement, is sustained throughout Parkinson's disease (PD). The vagus nerve, shown by ultrasonography, is atrophic in PD patients. We examined vagus nerve cross-sectional area (CSA) in controls versus PD patients, and its association with autonomic function in early PD.

Methods: We investigated 118 de novo PD patients and 29 controls. Vagus nerve CSA was measured using nerve ultrasonography at the bilateral mid-cervical area. Each patient was evaluated once by a randomly assigned sonographer; each control was measured twice by both. For accurate comparison, patients with diabetes were additionally excluded from the PD group. A 1:1 propensity score matching based on age, sex, hypertension, and dyslipidemia was performed. The CSA was compared between matched patients and controls. Clinical interviews, rating scales, and autonomic and olfactory function tests were performed. The association between these results and the CSA was analyzed.

Results: Median right and left vagus nerve CSA measured 1.3 and 1.2 mm², respectively, significantly lower than in controls (2.3 and 2.2 mm²). Partial correlation analysis showed a negative correlation between the right vagus CSA and abnormal heart rate response to deep breathing (rho = -0.191, P = 0.045).

Conclusion: Small right vagus nerve CSA is associated with early parasympathetic dysfunction in PD patients. These findings support the use of vagus nerve ultrasound as a potential non-invasive biomarker for identifying prodromal autonomic involvement and informing future early intervention research.

Purpose: In pediatric postural tachycardia syndrome (POTS), presyncope is important yet undercharacterized. It undermines school participation and daily function, while objective bedside markers remain limited. We aimed to delineate clinically usable predictors by integrating cardiovascular responses and cerebral oxygenation during active standing. We operationalized presyncope as visual darkening and examined three physiological correlates: heart rate change (ΔHR), recovery time, and cerebral oxygenation (ΔOxyHb).

Methods: We conducted a cross-sectional study of 49 pediatric patients with POTS (median age 14.2 years, 46.9% male). Continuous heart rate, blood pressure, and cerebral oxygenation were recorded during a 10-min active standing test; body mass index, inferior vena cava collapsibility index, and urinary sodium were also obtained. Robust regression identified independent predictors of visual darkening.

Results: ΔHR emerged as the strongest predictor of visual darkening (coefficient 0.017, 95% CI 0.005-0.030, p = 0.004), followed by recovery time (coefficient 0.005, 95% CI 0.000-0.010, p = 0.055) and ΔOxyHb (coefficient 0.029, 95% CI  - 0.005 to 0.064, p = 0.098). The final model demonstrated strong discriminative ability (AUC 0.842). Patients reporting visual darkening exhibited significantly higher ΔHR (49 [42-59] vs. 41 [38-46] bpm, p = 0.009), longer recovery time (21 [19-28] vs. 19 [17-22] s, p = 0.041), and greater ΔOxyHb reduction (- 8.7 [ - 10.4 to - 2.4] vs. - 3.5 [- 7.0 to - 2.5] μmol/L, p = 0.039).

Conclusions: Heart rate change upon standing is the most significant and clinically accessible predictor of visual darkening in pediatric POTS. The combined assessment of ΔHR, recovery time, and cerebral oxygenation offers a comprehensive evaluation of the risk of visual darkening, enabling personalized management strategies for pediatric patients.

Purpose: Orthostatic hypotension (OH) is a non-motor feature in people with Parkinson's disease that can lead to falls from syncope. Current knowledge is lacking on the effects of OH on gait function.

Methods: Participants enrolled in a prospectively monitored longitudinal cohort who had OH on vitals at one of two consecutive visits approximately 6 months apart were analyzed. Gait measures were compared at the orthostatic versus non-orthostatic visit using the Wilcoxon signed-rank test and a linear mixed model. Motor and non-motor assessments were also compared.

Results: Thirty-nine people with Parkinson's disease and seven age-matched controls in the longitudinal study met the inclusion criteria. Mean stride length and foot-strike length were shorter, and stride velocity was slower at the orthostatic visit compared to the non-orthostatic visit in people with Parkinson's disease. Levodopa dose, duration from last dose, motor and total Unified Parkinson's Disease Rating Scale scores, and cognitive and non-motor assessment scores did not differ between visits. The number of people reporting falls was higher at the orthostatic visit, and the fall frequency in fallers also trended higher. Gait measures did not differ between those with and without symptomatic OH.

Conclusion: In our cohort of people with Parkinson's disease with repeated measures, gait was more parkinsonian (slower velocity, shorter stride, and decreased foot strike to the ground) when they had OH on vitals at the visit than when they did not. Based on our results, future studies exploring the impact of adequate treatment of OH on gait function are warranted.

Purpose: Postural orthostatic tachycardia syndrome (POTS) is characterized by an excessive heart rate increase upon standing, often associated with dizziness, gastrointestinal symptoms, and decreased functional capacity. Acute hepatic porphyrias (AHP) are rare metabolic disorders with nonspecific neurovisceral and autonomic symptoms, some of which overlap with POTS. The purpose of this study was to evaluate AHP by molecular and biochemical testing in patients with POTS.

Methods: We studied 50 patients diagnosed with POTS and gastrointestinal symptoms at the Vanderbilt Autonomic Dysfunction Center. They underwent neuro-hormonal evaluation for POTS and genetic and biochemical screening for AHP. Genetic testing was aimed mainly at the four genes relevant to AHPs. Porphobilinogen (PBG), delta-aminolevulinic acid (ALA), and total porphyrins were measured in urine with normalization to creatinine.

Results: The average age of the patients was 33 ± 8.6 years, 96% were female, and the average BMI was 28 ± 7.2 kg/m², average systolic blood pressure was 120 ± 15.5 mmHg, average heart rate was 77 ± 13.6 bpm at baseline, and average SBP was 126 ± 19.1 mmHg. A heart rate of 111 ± 15.8 bpm at 10 min upright, showed normal cardiovascular reflexes. The COMPASS-31 total score was 32 ± 8.4, with a normal autonomic function test. Urine PBG averaged 1 ± 0.7 mg/g creatinine, ALA 2 ± 0.9 mg/g creatinine, and total porphyrins 172 ± 74.2 mmol/g creatinine, which were all normal. None had variants in the four genes associated with AHPs. Three patients were heterozygous for a common low expression ferrochelatase gene variant (FECH).

Conclusions: We found no evidence of AHP in patients with POTS with uncontrolled gastrointestinal symptoms, suggesting that screening for AHP, a rare genetic disorder, may not be warranted.

Purpose: Hypertension is characterised by both enlarged perivascular spaces (ePVS) and chronically elevated resting sympathetic outflow. ePVS is associated with heart rate variability, suggesting links to autonomic outflow; however, heart rate variability offers limited information on sympathetic nerve activity. Here, we assessed whether ePVS are associated with muscle sympathetic nerve activity (MSNA) in 25 hypertensive patients and 50 healthy normotensive adults.

Methods: T1-weighted MRI anatomical brain images were analysed for ePVS using a deep learning-based segmentation algorithm (nnU-Net). Spontaneous bursts of MSNA were recorded from the right common peroneal nerve via a tungsten microelectrode immediately before the MRI scan in a supine position. A backward regression analysis was conducted to test the relationship between ePVS and MSNA.

Results: Significant associations were found between MSNA and ePVS in the white matter (β = 1.02, p = 0.007), basal ganglia (β = 0.43, p = 0.001), and hippocampus (β = 0.24, p = 0.010) in healthy normotensive adults. Similar associations were observed in individuals with hypertension. Notably, the association between MSNA and midbrain ePVS cluster was only observed in the hypertensive group (β = 0.41, p = 0.005).

Conclusion: ePVS were associated with MSNA in both normotensive and hypertensive patients. These findings warrant further research into the causal relationship between MSNA and ePVS and highlight the potential for ePVS as a neuroimaging biomarker for sympathetic nerve activity.

Purpose: In our previous study (Manabe et al., J Appl Physiol 128:1196-1206, 1985), we demonstrated that the cerebral and cardiovascular responses induced by a pre-exercise countdown elicited peripheral vasodilation via baroreflex-mediated sympathetic withdrawal, which is likely advantageous for rapid oxygen delivery to contracting skeletal muscles in young men. Whether this is also true in young women, who generally show different neuro-cardiovascular responses to stress compared to men, remains unknown. Thus, we examined whether biological sex would affect the neuro-cardiovascular responses to anticipation before exercise.

Methods: Young healthy women (n = 11) and men (n = 10) performed 1 min of static handgrip at 30% of maximal voluntary contraction force twice; once with a 30 sec countdown and once after being immediately signaled to begin exercise (without countdown), with the order randomized. Middle cerebral artery blood velocity (V_MCA; transcranial Doppler), heart rate (HR), cardiac index [CI; HR × stroke volume (Modelflow)/body surface area], mean arterial pressure (MAP; finger photoplethysmography), muscle sympathetic nerve activity (MSNA; microneurography), and leg vascular conductance [LVC = superficial femoral artery blood flow (ultrasound)/MAP] were measured continuously.

Results: During countdown, women exhibited smaller increases in CI, MAP, and LVC and a smaller decrease in MSNA than men (p < 0.05). Increases in V_MCA and HR, and the sympathetic baroreflex sensitivity did not differ between sexes (p > 0.05).

Conclusion: Young women seem to have less baroreflex-mediated sympathetic withdrawal and peripheral vasodilatory responses to the countdown compared to young men, despite similar cerebral vascular responses. These findings may suggest women have reduced neuro-vascular responses to exercise anticipation, which could impact the ability of oxygen delivery at exercise onset.