Articles: vagus-nerve-physiopathology.
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Migraine pathophysiology includes altered brainstem excitability, and recent neuromodulatory approaches aimed at controlling migraine episodes have targeted key brainstem relay and modulatory nuclei. In this study, we evaluated the impact of respiratory-gated auricular vagal afferent nerve stimulation (RAVANS), a novel neuromodulatory intervention based on an existing transcutaneous vagus nerve stimulation approach, in the modulation of brainstem activity and connectivity in migraine patients. We applied 3T-functional magnetic resonance imaging with improved in-plane spatial resolution (2.62 × 2.62 mm) in episodic migraine (interictal) and age- and sex-matched healthy controls to evaluate brain response to RAVANS (gated to either inhalation or exhalation) and sham stimulation. ⋯ Increased connectivity was inversely correlated with relative time to the next migraine attack, suggesting clinical relevance to this change in connectivity. Poststimulation effects were also noted immediately after eRAVANS, as we found increased activation in putative pontine serotonergic (ie, nucleus raphe centralis) and noradrenergic (ie, locus coeruleus) nuclei in response to trigeminal sensory afference. Regulation of activity and connectivity of brainstem and cortical regions involved in serotonergic and noradrenergic regulation and pain modulation may constitute an underlying mechanism supporting beneficial clinical outcomes for eRAVANS applied for episodic migraine.
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J Clin Monit Comput · Aug 2017
Observational StudySympatho-vagal balance, as quantified by ANSindex, predicts post spinal hypotension and vasopressor requirement in parturients undergoing lower segmental cesarean section: a single blinded prospective observational study.
Hypotension subsequent to spinal anesthesia occurs in a significant number of parturients undergoing lower segment caesarian section. Currently available methods to predict the incidence of hypotension, its severity and the outcome are sub-optimal. Many workers have used basal heart rate as one of the predictors. ⋯ Higher ANSindex value was significantly associated with post spinal hypotension (p 0.017). A value of 24 % indicated the critical level above which hypotension appeared commonly. The ANSindex value might help anesthesiologist to anticipate and prepare for hypotension that is likely to ensue.
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Review Meta Analysis
A Meta-analysis on Resting State High-frequency Heart Rate Variability in Bulimia Nervosa.
Autonomic nervous system function is altered in eating disorders. We aimed to quantify differences in resting state vagal activity, indexed by high-frequency heart rate variability comparing patients with bulimia nervosa (BN) and healthy controls. ⋯ Findings suggest higher vagal activity in BN at rest, particularly in unmedicated samples with lower body mass index. Potential mechanisms underlying these findings and implications for routine clinical care are discussed. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.
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To assess the physiological meanings of the detrended fluctuation analysis (DFA) slope α and its relationship to spectral measures in heart rate variability, this study investigated changes of α and its corresponding spectral measures over various night-sleep stages. ⋯ The REM sleep attenuations appeared in ln(HF) and its derivatives, such as ln(LF/HF), ln(VLF/HF), and the overall DFA slope α values. The quantitative function of ln(VLF/HF) describes the α values constantly for overnight sleep stages, and it is not affected by age, LF, PLM, and AHI. Our findings therefore suggest that in sleep studies with spectral HRV measures, ln(VLF/HF) as a surrogate of the overall DFA slope α should be calculated at the same time.