Preliminary design and testing of neck chamber device for baroreflex sensitivity assessment

2020 ◽  
Vol 6 (4) ◽  
pp. 132-142
Author(s):  
Pratik V Paliwal ◽  
Prathamesh H Kamble ◽  
K A Desai ◽  
Rajesh Sharma ◽  
Anish Singhal
Keyword(s):  
Standard Test ◽  
Design Development ◽  
Test Protocol ◽  
Non Invasive ◽  
Carotid Baroreceptor ◽  
Sensitivity Assessment ◽  
Neck Chamber ◽  
Design And Testing ◽  
Opening Up ◽  
Stimulation Of

This paper presents the design, development and testing of a novel neck chamber device for non-invasive stimulation of an individual carotid baroreceptor in a graded manner. The proposed neck chamber device is a strap-free design that avoids discomfort during testing due to tight seal generated by the neck collar design, and facilitates unilateral testing and targeted assessment without stimulating other neck baroreceptors. The device consists of two independent components to achieve these requirements: an outer suction mechanism and an inner chamber. The outer mechanism consists of multiple suction cups to grip the device over the human neck, while the inner chamber creates controlled positive and negative pressure for stimulation of baroreceptors using a pump. The indigenously developed device was employed for the testing by providing neck chamber stimulation in discrete steps of –20 mm Hg, –40 mm Hg, −60 mm Hg, 0 mm Hg, 20 mm Hg, 40 mm Hg and 60 mm Hg with the gap of 60 s between each stimulation as per the standard test protocol of autonomic function test. The changes in heart rate and RR interval were recorded to determine the baroreceptor gain using the logistic equation derivative and gain curve plot. The results of the present study show that the estimated baroreceptor gain is –0.109±0.04, which is consistent with the previous studies conducted using neck collar devices. The testing results showed that the desired objectives are achieved successfully by the prototype device, opening up the possibility of its use for the treatment of resistant hypertension.

Baroreflex Sensitivity Assessment – Latest Advances and Strategies

2011 ◽  
Vol 7 (2) ◽  
pp. 89 ◽  
Author(s):  
Maria Teresa La Rovere ◽  
Roberto Maestri ◽  
Gian Domenico Pinna ◽  
◽  
◽  
...  
Keyword(s):  
Baroreflex Sensitivity ◽  
Carotid Sinus ◽  
Lower Blood Pressure ◽  
Vasomotor Tone ◽  
Sensitivity Assessment ◽  
Lower Blood ◽  
Prognostic Implications ◽  
Novel Therapeutic Strategies ◽  
Sympathetic Vasomotor Tone ◽  
Stimulation Of

The baroreflex mechanism has been recognised as a key part of cardiovascular regulation. Alterations in the baroreceptor-heart rate reflex (baroreflex sensitivity [BRS]) contribute to sympathetic–parasympathetic imbalance, playing a major role in the development and progression of many cardiovascular disorders. Therefore, the measurement of the baroreflex is a source of valuable information in the clinical management of cardiac disease patients. This article reviews the most relevant advances for the measurement of BRS and their clinical and prognostic implications. Novel therapeutic strategies, exploring the use of electrical stimulation of the carotid sinus, have been evaluated recently in experimental and preliminary clinical studies to lower blood pressure and to reduce the level of baroreflex-mediated sympathoexcitation in heart failure. A recent study has also shown that the implementation of an artificial baroreflex system to regulate sympathetic vasomotor tone automatically is feasible.

Non-invasive electrical stimulation of oropharyngeal muscles in obstructive sleep apnoea

2021 ◽  
Author(s):  
Juan Luis RodrÍguez Hermosa ◽  
Myriam Calle ◽  
Ina Guerassimova ◽  
Baldomero FernÁndez ◽  
Víctor Javier Montero ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Obstructive Sleep Apnoea ◽  
Sleep Apnoea ◽  
Non Invasive ◽  
Obstructive Sleep ◽  
Stimulation Of

The Use of Primary Cultured Rat Hepatocytes for the Assessment of Xenobiotic Effects on Biotransformation

1991 ◽  
Vol 19 (2) ◽  
pp. 209-213
Author(s):  
Gabi Schepers ◽  
Christiane Aschmann ◽  
Sabine Mörchel
Keyword(s):  
Cell Viability ◽  
Rat Hepatocytes ◽  
Standard Test ◽  
In Vitro Test ◽  
Chlorinated Phenols ◽  
Test Protocol ◽  
Primary Cultured Rat Hepatocytes ◽  
Cultured Rat Hepatocytes ◽  
Different Response

An in vitro test protocol is reported, which, using primary cultured rat hepatocytes, allows for the screening of xenobiotic effects on biotransformation as well as on basal cellular functions. O-Deethylation of 7-ethoxycoumarin (7-EC) and subsequent conjugation of the metabolite 7-hydroxycoumarin (7-HC) with sulphate or glucuronic acid are determined, as representative parameters for the hepatic biotransformation. Cell viability is examined by measuring cellular ATP content and leakage of lactate dehydrogenase. With respect to immediate and delayed effects on biotransformation reactions, the standard test protocol includes exposure to xenobiotics for 1, 24 and 48 hours. Different response patterns could be demonstrated for the solvents dimethylformamide (DMF) and dimethylsulphoxide (DMSO), and the chlorinated phenols, pentachlorophenol (PCP) and hexachlorophene (HCP), which are known to uncouple mitochondrial respiration. Short-term incubation with the solvents resulted in decreased 7-EC- O-deethylation without signs of cytotoxicity. PCP and HCP inhibited 7-EC- O-deethylation and 7-HC-conjugation, affecting sulphate and glucuronide formation differently. 24-hour exposures to PCP and HCP resulted in decreased 7-ethoxycoumarin- O-deethylase activity, which correlated with diminished cell viability, while DMSO and DMF enhanced 7-EC- O-deethylation at sub-cytotoxic concentrations. After exposure for 48 hours to the solvents, enzyme induction was even more pronounced.

scholarly journals Non-invasive stimulation of the motor cerebellum has potential cognitive confounds

2021 ◽  
Author(s):  
Robert M. Hardwick ◽  
Amanda S. Therrien ◽  
Elise Lesage
Keyword(s):  
Non Invasive ◽  
Stimulation Of

A methodological reappraisal of non invasive high voltage electrical stimulation of lumbosacral nerve roots

2011 ◽  
Vol 122 (10) ◽  
pp. 2071-2080 ◽  
Author(s):  
Walter Troni ◽  
Alessia Di Sapio ◽  
Eliana Berra ◽  
Sergio Duca ◽  
Aristide Merola ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
High Voltage ◽  
Nerve Roots ◽  
Non Invasive ◽  
Stimulation Of

Sympathetic transients caused by abrupt alterations of carotid baroreceptor activity in humans

1982 ◽  
Vol 242 (2) ◽  
pp. H185-H190 ◽  
Author(s):  
B. G. Wallin ◽  
D. L. Eckberg
Keyword(s):  
Sympathetic Activity ◽  
Chamber Pressure ◽  
Reduced Pressure ◽  
Cardiac Responses ◽  
Carotid Baroreceptor ◽  
Sympathetic Responses ◽  
Nerve Muscle ◽  
Neck Pressure ◽  
Pressure Changes ◽  
Neck Chamber

We examined the role of carotid baroreceptors in the short-term modulation of sympathetic outflow to the muscle vascular bed and parasympathetic outflow to the heart in 10 healthy adults. Afferent carotid baroreceptor activity was modified with 30-mmHg neck suction or pressure applied during held expiration, and efferent sympathetic activity was measured with microelectrodes inserted percutaneously into peroneal nerve muscle fascicles. Sympathetic responses were conditioned importantly by directional changes of carotid transmural pressure: increased pressure (onset of neck suction or offset of neck pressure) inhibited (totally) sympathetic activity, and reduced pressure (offset of neck suction or onset of neck pressure) augmented sympathetic activity. Responses occurred after a latency of about 2 s and did not persist as long as changes of neck-chamber pressure. Cardiac intervals were prolonged by increased carotid transmural pressures and shortened by decreased carotid transmural pressures, but, in contrast to sympathetic responses, cardiac responses adapted only slightly during neck-chamber pressure changes. Our results suggest that in the human a common baroreceptor input is processed differently in central vagal and sympathetic networks. Muscle sympathetic responses to changing levels of afferent baroreceptor traffic are profound but transitory. They appear to be conditioned more by changes of arterial pressure than by its absolute levels.

scholarly journals Electro-haptic hearing: Speech-in-noise performance in cochlear implant users is enhanced by tactile stimulation of the wrists

2019 ◽  
Author(s):  
Mark D. Fletcher ◽  
Amatullah Hadeedi ◽  
Tobias Goehring ◽  
Sean R Mills
Keyword(s):  
Cochlear Implant ◽  
Speech Intelligibility ◽  
Tactile Stimulation ◽  
Electrical Signal ◽  
Noise Performance ◽  
Speech In Noise ◽  
Non Invasive ◽  
Real World Application ◽  
Before And After ◽  
Stimulation Of

Cochlear implant (CI) users receive only limited sound information through their implant, which means that they struggle to understand speech in noisy environments. Recent work has suggested that combining the electrical signal from the CI with a haptic signal that provides crucial missing sound information (“electro-haptic stimulation”; EHS) could improve speech-in-noise performance. The aim of the current study was to test whether EHS could enhance speech-in-noise performance in CI users using: (1) a tactile signal derived using an algorithm that could be applied in real time, (2) a stimulation site appropriate for a real-world application, and (3) a tactile signal that could readily be produced by a compact, portable device. We measured speech intelligibility in multi-talker noise with and without vibro-tactile stimulation of the wrist in CI users, before and after a short training regime. No effect of EHS was found before training, but after training EHS was found to improve the number of words correctly identified by an average of 8.3 %-points, with some users improving by more than 20 %-points. Our approach could offer an inexpensive and non-invasive means of improving speech-in-noise performance in CI users.

scholarly journals Non-invasive stimulation of vagal afferents reduces gastric frequency

2019 ◽  
Author(s):  
Vanessa Teckentrup ◽  
Sandra Neubert ◽  
João C. P. Santiago ◽  
Manfred Hallschmid ◽  
Martin Walter ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Vagus Nerve ◽  
Energy Homeostasis ◽  
Resting Energy Expenditure ◽  
Vagal Afferents ◽  
Metabolic Effects ◽  
Net Energy ◽  
Non Invasive ◽  
Induced Changes ◽  
Stimulation Of

AbstractMetabolic feedback between the gut and the brain relayed via the vagus nerve contributes to energy homeostasis. We investigated in healthy adults whether non-invasive stimulation of vagal afferents impacts energy homeostasis via efferent effects on metabolism or digestion. In a randomized crossover design, we applied transcutaneous auricular vagus nerve stimulation (taVNS) while recording efferent metabolic effects using simultaneous electrogastrography (EGG) and indirect calorimetry. We found that taVNS reduced gastric myoelectric frequency (p =.008), but did not alter resting energy expenditure. We conclude that stimulating vagal afferents induces gastric slowing via vagal efferents without acutely affecting net energy expenditure at rest. Collectively, this highlights the potential of taVNS to modulate digestion by activating the dorsal vagal complex. Thus, taVNS-induced changes in gastric frequency are an important peripheral marker of brain stimulation effects.

Time-dependent Changes in Prostaglandin Excretion in Response to Frusemide in Man

1979 ◽  
Vol 56 (1) ◽  
pp. 77-81 ◽  
Author(s):  
B. Scherer ◽  
P. C. Weber
Keyword(s):  
Haemodynamic Effects ◽  
Invasive Technique ◽  
Urinary Volume ◽  
Clear Cut ◽  
Non Invasive ◽  
Urinary Potassium ◽  
The One ◽  
Vascular Compartment ◽  
Stimulation Of

1. To evaluate in man by a non-invasive technique the possible role of prostaglandin (PG) compounds in initial renal haemodynamic effects after frusemide we studied the urinary excretion of PGE2 and of PGF2α before and at 15 min and 120 min after intravenous injection of this drug. 2. An increase of PGE2 and of PGF2α excretion was found in all 19 volunteer subjects within 15 min after frusemide, and PG excretion had returned towards control values at 120 min. The stimulation of PGF2α excretion by frusemide was markedly lower in men than in women, but this difference was statistically not significant. 3. No clear-cut relation was found between urinary PG compounds, on the one hand, and urinary volume, urinary sodium and urinary potassium, on the other hand, during the study. 4. The results support the assumption that the rapid increase of urinary PG compounds after frusemide, which parallels the changes in renal haemodynamics, may be an indicator of an activation of the PG system, in part or predominantly, in the vascular compartment.

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