Search results for "Healthy Volunteers"
showing 10 items of 219 documents
Investigating cardiac and respiratory determinants of heart rate variability in an information-theoretic framework.
2014
This study was aimed at comparing two alternative information-theoretic approaches for the combined analysis of heart rate variability (HRV) and respiration variability (RV). The approaches decompose the predictive information about HRV in two terms, quantifying respectively the information stored into HRV and that transferred to HRV from RV. Storage and transfer were assessed by the popular self entropy (SE) and transfer entropy (TE) measures, as well as by the alternative conditional SE (cSE) and cross entropy (CE) measures. The comparison was performed at a theoretical level, computing the exact values of the four measures for simulated cardiorespiratory dynamics, and on real data, estim…
Causal relationships in the variability of cardiovascular system evoked by orthostatic stress by transfer entropy.
2015
The coupling between cardiac and vascular systems in healthy volunteers, elicited by the head-up tilt test is estimated by means of transfer entropy with non-uniform embedding. The method applied to beat-to-beat recordings with heart periods and systolic blood pressure, supports the commonly accepted model, that baroreflex is the key factor in maintaining homeostatic blood distribution after tilting. However the method applied to changes of heart periods and changes of blood pressure, display switches in the driving system, from vascular in the early tilt, to cardiac just after the early tilt and back to vascular in the late tilt.
Normal reference values of multilayer longitudinal strain according to age decades in a healthy population: A single-centre experience.
2017
Aims Recent advancements in echocardiographic technology allow to analyse myocardial strain in multiple layers. Little is known about the impact of age on layer-specific longitudinal strain in healthy subjects. The aim of this study was to analyse the influence of age on multilayer longitudinal strain and establish normal reference values of layer-specific strain according to age decades in a healthy population referring to our echo laboratory using 2D speckle-tracking echocardiography with layer-specific software. Methods and results Two-hundred sixty-six healthy, consecutive subjects (mean age = 39.2 ± 17.5 years, women/men = 137/129), free of cardiovascular risk factors, were enrolled. S…
3D echocardiographic reference ranges for normal left ventricular volumes and strain: results from the EACVI NORRE study
2017
International audience; Aim: To obtain the normal ranges for 3D echocardiography (3DE) measurement of left ventricular (LV) volumes, function, and strain from a large group of healthy volunteers. Methods and results: A total of 440 (mean age: 45 ± 13 years) out of the 734 healthy subjects enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study had good-quality 3DE data sets that have been analysed with a vendor-independent software package allowing homogeneous measurements regardless of the echocardiographic machine used to acquire the data sets. Upper limits of LV end-diastolic and end-systolic volumes were larger in men (97 and 42 mL/m2)…
The effect of acupuncture on oral microcirculation in healthy volunteers: an exploratory study.
2009
Background Acupuncture is a therapeutic technique currently used in the treatment of many pathologies. The aim of this study is to evaluate the potential effect of acupuncture on “in vivo” variations in oral microcirculation in healthy subjects. Methods An exploratory study was conducted on 40 healthy subjects: 20 cases (mean 55.90, SD 16.04) and 20 controls (mean 51, SD 11.91). Videocapillaroscopy was used to detect variations in oral microcirculation. This method permits an accurate and non-invasive in vivo study of the capillaries of the oral mucous. The site selected for this pilot study is the lower lip since it is the simplest to investigate and is more readily accessible. Assessments…
Contributions of individual muscles to the sagittal- and frontal-plane angular accelerations of the trunk in walking.
2013
This study was conducted to analyze the unimpaired control of the trunk during walking. Studying the unimpaired control of the trunk reveals characteristics of good control. These characteristics can be pursued in the rehabilitation of impaired control. Impaired control of the trunk during walking is associated with aging and many movement disorders. This is a concern as it is considered to increase fall risk. Muscles that contribute to the trunk control in normal walking may also contribute to it under perturbation circumstances, attempting to prevent an impending fall. Knowledge of such muscles can be used to rehabilitate impaired control of the trunk. Here, angular accelerations of the t…
Oesophageal motility disorders in type 1 diabetes mellitus and their relation to cardiovascular autonomic neuropathy.
2006
The relationship between cardiovascular autonomic neuropathy (CVAN) and oesophageal dysfunction in diabetes mellitus has not been well established because reports are contradictory. The aim of this study was to assess oesophageal function and its correlation with CVAN in type 1 diabetic patients without oesophageal symptoms. Forty-six type 1 diabetic patients without oesophageal symptoms (DG) and 34 healthy volunteers (CG) were studied. Both groups underwent CVAN tests and oesophageal manometry and pH-metry. Differences between groups regarding results of cardiovascular autonomic tests and oesophageal studies were statistically analysed. Compared with the CG, the DG group showed insufficien…
Investigating prismatic adaptation effects in handgrip strength and in plantar pressure in healthy subjects.
2020
Abstract Background Prismatic Adaptation (PA) is a visuomotor procedure inducing a shift of the visual field that has been shown to modulate activation of a number of brain areas, in posterior (i.e. parietal cortex) and anterior regions (i.e. frontal cortex). This neuromodulation could be useful to study neural mechanisms associated with either postural measures such as the distribution of plantar pressure or to the generation of muscle strength. Indeed, plantar pressure distribution is associated to activation of high-level cognitive mechanisms taking place within the posterior regions of the brain dorsal stream, especially of the right hemisphere. Conversely, hand force mostly rely on sen…
Selective activation of shoulder, trunk, and arm muscles: A comparative analysis of different push-up variants
2015
Context The push-up is a widely used exercise for upper limb strengthening that can be performed with many variants. A comprehensive analysis of muscle activation during the ascendant phase (AP) and descendant phase (DP) in different variants could be useful for trainers and rehabilitators. Objective To obtain information on the effect of different push-up variants on the electromyography (EMG) of a large sample of upper limb muscles and to investigate the role of the trunk and abdomen muscles during the AP and DP. Design Cross-sectional study. Setting University laboratory. Patients or Other Participants Eight healthy, young volunteers without a history of upper extremity or spine injury.…
Microcentrifuge or Automated Hematological Analyzer to Assess Hematocrit in Exercise? Effect on Plasma Volume Loss Calculations
2016
The assessment of plasma volume loss (∆PV) induced by exercise can be estimated from changes in hematocrit (Htc) and hemoglobin (Hb), and it is essential when investigating the metabolic or biologic response to exercise of circulating biomarkers. We aimed to ascertain whether the estimation of ∆PV may differ when Hb and Htc are determined by automated hematological analyzer (AHA) versus manual methods. Twenty-five healthy male subjects performed a maximal running incremental exercise. Blood samples were taken before exercise, immediately after exercise, and after a 30-min recovery. Hb and Htc (Htc-AHA) were determined by an AHA. Htc was also determined by microcentrifugation (Htc-M). The ∆P…