The nondipping blood pressure (BP) pattern corresponds to a disruption in the circadian BP rhythm with an insufficient decrease in BP levels during night-time sleep as observed using 24-hour ambulatory BP monitoring. Patients with nondipping BP pattern have poorer renal and cardiovascular outcomes, independent of their average 24-hour BP levels. The pathophysiology of nondipping BP is complex and involves numerous mechanisms: perturbations of (1) the circadian rhythm, (2) the autonomic nervous system, and (3) water and sodium regulation. This review provides an outline of the pathways potentially involved in the nondipping BP profile in different conditions. A recent hypothesis is also discussed involving the role of gut microbiota in the dipping/nondipping patterns, via the fecal diet-derived short chain fatty acids.

Recovery of mimic function after facial nerve transection is poor. The successful regrowth of regenerating motor nerve fibers to reinnervate their targets is compromised by (i) poor axonal navigation and excessive collateral branching, (ii) abnormal exchange of nerve impulses between adjacent regrowing axons, namely axonal crosstalk, and (iii) insufficient synaptic input to the axotomized facial motoneurons. As a result, axotomized motoneurons become hyperexcitable but unable to discharge. We review our findings, which have addressed the poor return of mimic function after facial nerve injuries, by testing the hypothesized detrimental component, and we propose that intensifying the trigeminal sensory input to axotomized and electrophysiologically silent facial motoneurons improves the specificity of the reinnervation of appropriate targets. We compared behavioral, functional, and morphological parameters after single reconstructive surgery of the facial nerve (or its buccal branch) with those obtained after identical facial nerve surgery, but combined with direct or indirect stimulation of the ipsilateral infraorbital nerve. We found that both methods of trigeminal sensory stimulation, i.e., stimulation of the vibrissal hairs and manual stimulation of the whisker pad, were beneficial for the outcome through improvement of the quality of target reinnervation and recovery of vibrissal motor performance.

An 80-year-old woman with a history of hypertrophic obstructive cardiomyopathy and Lewy body dementia was admitted to our hospital with a first episode of syncope while walking. The pressure gradient of left ventricular outflow tract (LVOT) had been stable at nearly 10 mmHg for 3 years before the admission. We evaluated the cause of syncope. Echocardiography showed that the pressure gradient of LVOT was unchanged, even in the supine position ergometer exercise test. Although the head-up tilt test revealed a drop in blood pressure of 44 mmHg systolic and 23 mmHg diastolic, she was asymptomatic during the test. The orthostatic hypotension was considered to be a manifestation of autonomic failure due to Lewy body dementia; however, it was insufficient to explain the syncope on exertion. Echocardiography in a sitting-up position showed that the pressure gradient of LVOT was exacerbated to 41 mmHg, which might be the cause of syncope while walking. Orthostatic hypotension, especially in patients with Lewy body dementia, is a common cause of syncope in the elderly. However, we should keep in mind that the exacerbation of LVOT obstruction due to posture-dependent fluid shift can be a cause of syncope in patients with hypertrophic cardiomyopathy or sigmoid-shaped interventricular septum. In such patients, echocardiography in a sitting-up position can be an effective tool to diagnose the cause of syncope.

Pregnancy complications are associated with insufficient adaptation of the maternal autonomic nervous system to the physiological demands of pregnancy. Consequently, assessing maternal heart rate variability (mHRV)-which reflects autonomic regulation-is a promising tool for detecting early deterioration in maternal health. However, before mHRV can be used to screen for complications, an understanding of the factors influencing mHRV during healthy pregnancy is needed. In this retrospective observational study, we develop regression models to unravel the effects of maternal demographics (age, body mass index (BMI), gestational age (GA), and parity), cardiorespiratory factors (heart rate and breathing rate), and inter-subject variation on mHRV. We develop these models using two datasets which are comprised of, respectively, single measurements in 290 healthy pregnant women and repeated measurements (median = 8) in 29 women with healthy pregnancies. Our most consequential finding is that between one-third and two-thirds of the variation in mHRV can be attributed to inter-subject variability. Additionally, median heart rate dominantly affects mHRV (p < 0.001), while BMI and parity have no effect. Moreover, we found that median breathing rate, age, and GA all impact mHRV (p < 0.05). These results suggest that personalized, long-term monitoring would be necessary for using mHRV for obstetric screening.

The aim of this study was to investigate the training-induced effect on cardiac parasympathetic nervous system (PNS) activity, assessed by resting heart rate variability (HRV) and post-exercise heart rate recovery (HRR), in sedentary healthy people. Electronic searches were carried out in PubMed, Embase, and Web of Science. Random-effects models of between-group standardised mean difference (SMD) were estimated. Heterogeneity analyses were performed by means of the chi-square test and I2 index. Subgroup analyses and meta-regressions were performed to investigate the influence of potential moderator variables on the training-induced effect. The results showed a small increase in RMSSD (SMD+ = 0.57 [95% confidence interval (CI) = 0.23, 0.91]) and high frequency (HF) (SMD+ = 0.21 [95% CI = 0.01, 0.42]) in favour of the intervention group. Heterogeneity tests reached statistical significance for RMSSD and HF (p ≤ 0.001), and the inconsistency was moderate (I2 = 68% and 60%, respectively). We found higher training-induced effects on HF in studies that performed a shorter intervention or lower number of exercise sessions (p ≤ 0.001). Data were insufficient to investigate the effect of exercise training on HRR. Exercise training increases cardiac PNS modulation in sedentary people, while its effect on PNS tone requires future study.

Allgrove syndrome (AS), or Triple-A syndrome, is a multi-system disorder characterized by alacrima (a decrease or absence of tear production), adrenal insufficiency and achalasia (absence of esophageal muscle peristalsis and failure to relax the lower esophageal sphincter). This syndrome may affect the autonomic nervous system, in which case it is called a 4A syndrome. It is a rare autosomal recessive inheritance, and early identification is difficult due to the rarity and wide phenotypic variation even among members of the same family. Endocrinologists, gastroenterologists, ophthalmologists, neurologists and surgeons are needed to coordinate care for these patients. We describe a case of AS that took several years to complete the diagnosis. She was diagnosed with alacrima at the age of 1-year-old, adrenal insufficiency at the age of 9 and achalasia at the age of 16. This case demonstrates the difficulty and delay in the diagnosis of AS.

As an optical system, the eyes function in line with the basic principles of refraction. Visual clarity depends on the ability to bring incident light rays to a point focus at the fovea centralis. Schematically, the cornea and crystalline lens provide the requisite total dioptric power (about +60 diopters; the cornea makes up about + 40 to + 48 diopters). Accommodation is the adaptative faculty that enables clear vision with subjective variation in the linear distance of visual targets. This is accomplished by the autonomic adjustment of crystalline lens dioptric powers to provide focus on the presented stimuli. The main stimulus is 'blur.' The focusing powers of the crystalline lens are directly proportional to the increase or decrease in lens convexity. At the near point of accommodation, the ciliary muscles contract and relax zonular tension, thus enabling increased convexity and focusing power. For the far point of accommodation, the ciliary muscles relax and exert greater tension on the zonules (of Zinn), thus reducing lenticular convexity.  Under typical conditions, the healthy eye responds to near-point (linear) stimuli by activating the near triad, which includes accommodation, convergence, and miosis. These mechanisms are synergistically engaged to enable single, clear binocular vision. Inhibition in one of these reflexes can most likely lead to dysfunction of accommodative response. Concerning the near reflexes, accommodation and convergence are most closely intertwined. This interrelationship can be reported as the 'accommodative convergence to accommodation (AC/A)  ratio. Depending on the underlying accommodative dysfunction, the ac/a ratio may be either low, normal, or high. The accommodative mechanisms can be subject to functional anomalies in maintaining visual clarity. Based on the Duke-Elder classification, these include: Accommodative insufficiency (AI). Accommodative spasm. Accommodative inertia. Ill-sustained accommodation. Accommodative infacility. AI is a functional vision anomaly characterized by the inability to sustain focus at near. With this condition, the accommodative response is often suboptimal compared to expected normal ranges.

In thyroid surgery, intra-operative neuromonitoring signals of the recurrent laryngeal nerve can be detected by surface electrodes on a tracheal tube positioned at the vocal fold level. The incidence of difficult tracheal intubation in patients undergoing thyroidectomy for nodular goitre ranges from 5.3% to 20.5%. The aim of this study was to compare videolaryngoscopy with conventional direct laryngoscopy as methods for proper placement of the surface electrode to prevent insufficient intra-operative nerve signal quality. In this prospective randomised trial, adult patients requiring tracheal intubation during thyroid surgery were randomly allocated to two groups of C-MAC® (Macintosh style blade) videolaryngoscope or direct laryngoscopy using the Macintosh laryngoscope. Primary outcome was the incidence of insufficient signal electromyogram amplitude level (< 500 μV) after successful tracheal intubation. A total of 260 (130 per group) participants were analysed. An insufficient signal was more frequent with direct laryngoscopy (35/130, 27%), compared with C-MAC (12/130, 9%, p < 0.001). First-pass tracheal intubation success rate was lower with direct laryngoscopy (86/130 (66%)) compared with the C-MAC (125/130 (96%)) (p < 0.0001). Cormack and Lehane grade ≥ 3 was observed more frequently with direct laryngoscopy (16/130 (12%)), compared with the C-MAC (0/130, (0%)) (p < 0.0001). The results suggest that videolaryngoscopy has an impact on the quality of the initial intra-operative neuromonitoring signal in patients undergoing thyroid surgery, and this technique can provide optimised surface electrode positioning.

Hypertension and chronic kidney disease are closely linked. Patients with chronic kidney disease have hypertension almost universally and uncontrolled hypertension accelerates the decline in kidney function. The pathophysiology of hypertension in chronic kidney disease is complex, but is largely related to reduced nephron mass, sympathetic nervous system overactivation, involvement of the renin-angiotensin-aldosterone system, and generalized endothelial dysfunction. Consensus guidelines for blood pressure targets have adopted a blood pressure <120/80 mm Hg in native chronic kidney disease and <130/80 mm Hg in kidney transplant recipients. Guidelines also strongly advocate for renin-angiotensin-aldosterone system blockade as the first-line therapy.

What is the central question of this study? What are the contributions of shear stress and adrenergic tone to brachial artery vasodilatation during hypercapnia? What is the main finding and its importance? In healthy young adults, shear-mediated vasodilatation does not occur in the brachial artery during hypercapnia, as elevated α₁-adrenergic activity typically maintains vascular tone and offsets distal vasodilatation controlling flow.

Fatigue is defined as a symptom leading to the inability to continue functioning at the expected activity level. It is a highly prevalent symptom, challenging to frame into monodimensional pathophysiological mechanisms. As a result, fatigue is often underestimated in the clinical setting and is wrongly considered an unavoidable consequence of ageing. Several potential mechanisms responsible for fatigue have been proposed, including sleep patterns, autonomic nervous system abnormalities and biological complexity. Inflammation and mitochondrial dysfunction are among the most promising mechanisms through which malnutrition may cause fatigue. Not surprisingly, fatigue is highly prevalent in inflammatory conditions (e.g. COVID-19 infection). The nutritional status may also represent a critical factor in the development and presentation of fatigue, which may mimic the exhaustion of the individual's metabolic reserves. For example, the insufficient dietary intake of energy and proteins may determine the catabolism of body fat and muscles, disrupt the homeostatic balance and cause the onset of fatigue. It is necessary to conduct research on fatigue. By characterising its pathophysiological mechanisms, it will be possible to (1) support the design and development of targeted interventions, (2) improve the quality of life of many persons by acting on the symptom and (3) reduce the direct and indirect costs of a burdening condition typical of advancing age. In the present review, we provide an overview of the role that nutrition may play as a determinant of fatigue in older people, also in the context of the COVID-19 pandemic.

Traditional video recommendation provides the viewers with customized media content according to their historical records (e.g., ratings, reviews). However, such systems tend to generate terrible results if the data is insufficient, which leads to a cold-start problem. An affective video recommender system (AVRS) is a multidiscipline and multimodal human-robot interaction (HRI) system, and it incorporates physical, physiological, neuroscience, and computer science subjects and multimedia resources, including text, audio, and video. As a promising research domain, AVRS employs advanced affective analysis technologies in video resources; therefore, it can solve the cold-start problem. In AVRS, the viewers' emotional responses can be obtained from various techniques, including physical signals (e.g., facial expression, gestures, and speech) and internal signals (e.g., physiological signals). The changes in these signals can be detected when the viewers face specific situations. The physiological signals are a response to central and autonomic nervous systems and are mostly involuntarily activated, which cannot be easily controlled. Therefore, it is suitable for reliable emotion analysis. The physical signals can be recorded by a webcam or recorder. In contrast, the physiological signals can be collected by various equipment, e.g., psychophysiological heart rate (HR) signals calculated by echocardiogram (ECG), electro-dermal activity (EDA), and brain activity (GA) from electroencephalography (EEG) signals, skin conductance response (SCR) by a galvanic skin response (GSR), and photoplethysmography (PPG) estimating users' pulse. This survey aims to provide a comprehensive overview of the AVRS domain. To analyze the recent efforts in the field of affective video recommendation, we collected 92 relevant published articles from Google Scholar and summarized the articles and their key findings. In this survey, we feature these articles concerning AVRS from different perspectives, including various traditional recommendation algorithms and advanced deep learning-based algorithms, the commonly used affective video recommendation databases, audience response categories, and evaluation methods. Finally, we conclude the challenge of AVRS and provide the potential future research directions.

The gut-brain axis describes a bidirectional interplay within the enteric environment between the intestinal epithelium, the mucosal immune system, and the microbiota with the enteric nervous system. This interplay provides a link between exogenous environmental stimuli such as nutrient sensing, and nervous system function, as well as a mechanism of feedback from cortical and sensory centers of the brain to enteric activities. The intestinal epithelium is one of the human body's largest sources of hormones and neurotransmitters, which have critical effects on neuronal function. The influence of the gut microbiota on these processes appears to be profound; yet to date, it has been insufficiently explored. Disruption of the intestinal microbiota is linked not only to diseases in the gut but also to brain symptomatology, including neurodegenerative and behavioral disorders (Parkinson disease, Alzheimer disease, autism, and anxiety and/or depression). In this review we discuss the cellular wiring of the gut-brain axis, with a particular focus on the epithelial and neuronal interaction, the evidence that has led to our current understanding of the intestinal role in neurologic function, and future directions of research to unravel this important interaction in both health and allergic disease.

The autonomic nervous system consists of the sympathetic and parasympathetic divisions. As the name implies, the lumbar sympathetic block can be utilized to disrupt the nerve supply from the sympathetic chain to the lower extremities. This is useful in treating sympathetic mediators of pain. Specifically, lumbar sympathetic blocks can be used for the treatment of painful conditions such as complex regional pain syndrome, phantom limb pain, hyperhidrosis, painful vascular insufficiencies, and pain from herpes zoster/shingles.[1][2]

A 47-year-old woman was admitted to our hospital for scrutiny of limb weakness and orthostatic hypotension that had progressed from childhood. She had been treated for alacrima and esophageal achalasia from childhood. On admission, she had hyperreflexia of upper and lower extremities, distal predominant muscle atrophy in the lower extremities, decreased sensation of the distal extremities, and autonomic neuropathy. Her blood test results ruled out adrenal insufficiency, but Schirmer's test was positive. Given the lacrimation symptoms, esophageal achalasia, and neuropathy, the patient was diagnosed with triple A syndrome in whom a c.463C>T mutation (p.R155C) was found in the AAAS gene by genetic testing. Triple A syndrome is an autosomal recessive inherited disease caused by mutations in the AAAS gene. Genetic testing of the AAAS gene should be considered in patients with one or two of main symptoms of triple A syndrome.

A growing body of evidence suggests that diabetes mellitus (DM) is associated with an increased risk of new-onset atrial fibrillation (AF) and contributes to suboptimal arrhythmia control and poor prognosis in patients with AF. The high prevalence of AF among patients with DM is primarily attributed to common risk factors, shared pathophysiological mechanisms, and associated atrial remodeling and autonomic dysfunction.

Excessive daytime sleepiness (EDS) is classified as a neurofunctional disorder that manifests as uncontrolled sleeping propensity in the daytime. Currently, consistent and effective therapeutic approaches for EDS are lacking. Stellate ganglion block (SGB) has a clear effect in various complicated pain syndromes, vascular insufficiency, hyperhidrosis, and posttraumatic stress syndrome. We report an EDS case that involved a patient who recovered after several sessions of SGB.