Clinical Autonomic Research最新文献

Purpose: A blood pressure stabilization during late phase II of Valsalva's maneuver may be utilized to confirm sympathetic vasoconstrictor control after a spinal cord injury. This study investigated whether Valsalva response was predictive of hemodynamics during tilt or isometric handgrip.

Methods: Presence/absence of Valsalva response was compared to heart rate, mean arterial pressure, leg blood flow, and vascular resistance during head-up tilt and isometric handgrip to fatigue in 14 adults with spinal cord injury from C7 to T12 and 14 controls. Statistics were performed with two-way repeated measure analysis of variance (ANOVA), post hoc t-tests for between-group comparisons, and Mann-Whitney U tests for within-group.

Results: In total, six participants with spinal cord injury lacked a blood pressure stabilization for Valsalva's maneuver. However, this was not related to vasoconstrictor responses during the other tests. The groups had similar heart rate and blood pressure changes during tilt, though leg blood flow decreases and vascular resistance increases tended to be smaller at 20° tilt in those with spinal cord injury (p = 0.07 and p = 0.11, respectively). Participants with spinal cord injury had lower heart rates and markedly smaller blood pressure increases during handgrip (both p < 0.05). There were no group differences in leg blood flow, but those with spinal cord injury demonstrated a blunted vascular resistance increase by the final 10% of the handgrip (p < 0.01).

Conclusions: Valsalva response was not consistent with hemodynamics during other stimuli, but some individuals evidence increases in sub-lesional vascular resistance to isometric handgrip comparable to controls, suggesting a sympathoexcitatory stimulus may be critical to provoke hemodynamic responses after spinal cord injury.

Purpose: Vagus nerve stimulation (VNS) is emerging as a unique and potent intervention, particularly within neurology and psychiatry. The clinical value of VNS continues to grow, while the development of noninvasive options promises to change a landscape that is already quickly evolving. In this review, we highlight recent progress in the field and offer readers a glimpse of the future for this bright and promising modality.

Methods: We compiled a narrative review of VNS literature using PubMed and organized the discussion by disease states with approved indications (epilepsy, depression, obesity, post-stroke motor rehabilitation, headache), followed by a section highlighting novel, exploratory areas of VNS research. In each section, we summarized the current role, recent advancements, and future directions of VNS in the treatment of each disease.

Results: The field continues to gain appreciation for the clinical potential of this modality. VNS was initially developed for treatment-resistant epilepsy, with the first depression studies following shortly thereafter. Overall, VNS has gained approval or clearance in the treatment of medication-refractory epilepsy, treatment-resistant depression, obesity, migraine/cluster headache, and post-stroke motor rehabilitation.

Conclusion: Noninvasive VNS represents an opportunity to bridge the translational gap between preclinical and clinical paradigms and may offer the same therapeutic potential as invasive VNS. Further investigation into how VNS parameters modulate behavior and biology, as well as how to translate noninvasive options into the clinical arena, are crucial next steps for researchers and clinicians studying VNS.

Purpose: Data on associations between adiposity and heart rate variability (HRV) in prepubertal children are limited. We examined the associations between adiposity indices and HRV, independent of lifestyle behaviors, comparing multiple indicators of adiposity, and explored differences between boys and girls.

Methods: Data stem from 469 participants of the QUALITY cohort (630 children aged 8-10 years with a parental history of obesity). Adiposity indices included waist-to-height ratio, body mass index (BMI) percentiles and categories (overweight, obesity), dual-energy x-ray absorptiometry (DEXA) defined fat mass percentage and android/gynoid ratio. HRV indices in the frequency and the spectral domain were derived from a daytime 3-h Holter recording. Multivariable linear regression models were adjusted for age, sex, Tanner stage, physical activity, screen time, and fitness. Interactions between sex and adiposity were tested.

Results: Greater adiposity was associated with decreased parasympathetic modulation and increased sympathetic dominance. Waist-to-height ratio was associated with lower parasympathetic activity: root mean square of the successive differences (RMSSD) [B =  -23.32, 95% confidence interval (CI) -42.42, -4.22], pNN50 (B =  -16.93, 95% CI - 28.58, - 5.27), LF/HF ratio (B = 1.83, 95% CI 0.97-2.70). Patterns of association were similar for android/gynoid ratio. Overweight was not associated with altered HRV. Obesity was negatively associated with RMSSD and pNN50 and positively with LF/HF ratio. Greater fat mass percentage was associated with lower RMSSD, pNN50, and HF, and increased LF/HF ratio. There were no differences between boys and girls.

Conclusions: Specific markers of adiposity relate to altered HRV in childhood, with waist-to-height ratio being potentially a more relevant marker of HRV than BMI and more pragmatic than percent body fat.

Trial registration: NCT03356262, 11 November 2017.

Purpose: Neurogenic orthostatic hypotension (nOH) and gait impairment are frequent sources of disability in Parkinson's disease (PD). However, the impact of nOH on balance and gait features remains unclear. This cross-sectional study aimed to assess the influence of nOH on postural and gait parameters in a cohort of patients with PD by means of wearable inertial sensors.

Methods: Gait and balance were assessed using Opal inertial sensors. nOH was defined as sustained systolic blood pressure (BP) drop ≥ 20 mmHg or diastolic BP drop ≥ 10 mmHg within 3 min of standing, with a ΔHR/ΔSBP ratio ≤ 0.5 bpm/mmHg. Analysis of covariance was performed to evaluate differences in gait/balance features between patients with and without nOH, adjusting for age, cognitive status, and motor disability. Moreover, we performed the same analysis considering the presence of hemodynamically relevant nOH (orthostatic mean BP ≤ 75 mmHg).

Results: A total of 82 patients were enrolled, 26 with nOH (31.7%), of which 13 presented with hemodynamically relevant nOH. After correcting for confounders, nOH was independently associated with lower gait speed (p = 0.027), shorter stride length (p = 0.033), longer time for postural transitions (p = 0.004), and increased postural sway (p = 0.019). These differences were even more pronounced in patients with hemodynamically relevant nOH. Higher postural sway was associated with a 7.9-fold higher odds of falls (p = 0.040).

Conclusions: Our study presents an objective demonstration of the independent negative impact of nOH on gait and balance in PD, emphasizing the need for careful detection and management of nOH to mitigate gait and balance disturbances in PD.

Purpose: Evidence from animal and human studies demonstrates that cortical regions play a key role in autonomic modulation with a differential role for some brain regions located in the left and right brain hemispheres. Known as autonomic asymmetry, this phenomenon has been demonstrated by clinical observations, by experimental models, and currently by combined neuroimaging and direct recordings of sympathetic nerve activity. Previous studies report peculiar autonomic-mediated cardiovascular alterations following unilateral damage to the left or right insula, a multifunctional key cortical region involved in emotional processing linked to autonomic cardiovascular control and featuring asymmetric characteristics.

Methods: Based on clinical studies reporting specific damage to the insular cortex, this review aims to provide an overview of the prognostic significance of unilateral (left or right hemisphere) post-insular stroke cardiac alterations. In addition, we review experimental data aiming to unravel the central mechanisms involved in post-insular stroke cardiovascular complications.

Results and conclusion: Current clinical and experimental data suggest that stroke of the right insula  can present a worse cardiovascular prognosis.