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The preservation of stability and body coordination in humans is assured by the correct working of the postural control system. Usually, postural oscillations is measured by the magnitude of center of pressure (CoP) movement over time. The conventional parameters in frequency domain to quantify changes of the CoP dynamics are estimated using Fourier spectral methods. However, considering the non-stationarity...
The quantitative assessment of the postural stability is allowed by means of the use of pressure or force plates which are able to record a CoP subject's trajectory during a quite standing. However, the pressure or force plates are commonly used in a clinical environment, due to their very complexity and expensiveness. So their applicability outside laboratories is extremely limited. New e-textile...
Linear measures of heart rate variability (HRV) during ECG stress test has been widely questioned due to the high signal non-stationary. Such limitations can be overcome by nonlinear measures of HRV based on typical properties of chaotic systems and deterministic fractal. Very few paper addressed such issue and aim of the paper is to describe fractal behavior of HRV during exercise. A fractal analysis...
Microvascular dysfunctions are responsible for the vascular complications of diabetes, frequently observed in obese subjects. The present study was aimed to assess microvascular skin blood flow and related oscillations in hyperglycemic obese subjects. Twenty-eight normoglycemic controls and twenty-nine hyperglycemic subjects were recruited from our Outpatient Clinics. Anthropometric measurements were...
Hypertension causes several microvascular alterations, leading to inadequate blood supply to tissues and target-organ damage. The present study was aimed to investigate microvascular skin blood flow and related oscillations in hypertensive obese subjects. Twenty-eight controls and twenty-seven hypertensive patients were recruited from our Outpatient Clinics. Anthropometric measurements were evaluated...
The present study was aimed to assess blood flow oscillatory patterns in rat pial microcirculation by laser speckle imaging. Laser speckle methods provides maps of cerebral blood flow with elevated temporal and spatial resolution. The study was carried out on male Wistar rats. An open cranial window was prepared on the parietal region. Pial arterioles were classified by Strahler method in five orders...
Although symbolic dynamics analysis (SDA) has been proposed for encoding words of different length and symbols, the resulting rapidly growing number of patterns has limited its clinical use. Aim of this study is to propose new SDA indices tested on a clinical data-set. We studied 40 ECG Holter of normal (NR), post-MI (MI), heart failure (HF) and transplanted (TR) subjects. RR differences were encoded...
Variations in kinematic performances and muscle activations, underlying improvements in muscle function and strength, in response to upper arm training of patients with congenital or acquired brain injuries, are still poorly understood. One of the most interesting features of a robotmediated therapy is the ability to quantify the performance of the rehabilitation tasks proposed to the patient. Although...
Among the plethora of indices that can describe the fractal-like behaviour of heart rate variability (HRV), the fractal dimension (FD) and the power-law exponent (β) have gained wide acceptance. Since HRV is generally modelled with fractional Brownian motion (fBm), the linear scaling relationship between β and FD, valid for fBm, is often applied to HRV series to derive one index from the other. In...
Cardiovascular oscillations following spontaneous ventricular premature complexes (VPC) are characterized by a short-term heart rate fluctuation known as heart rate turbulence (HRT) described by the so-called turbulence onset (TO) and slope (TS). Despite a recent written consensus on the standard of HRT measurement, reproducibility data are lacking. Aim of the paper was a reproducibility study of...
To evaluate the relationship between lesion's severity and nonlinear indexes of HRV, 20 first-ever stroke subjects and 10 healthy subjects were studied. All patients, divided in two groups according to presence of single or multiple medium cerebral artery lesion, underwent to a 24-hour Hotter ECG recording. All RR time series were analyzed by Poincare Plot, fractal dimension, power-law behaviour,...
This study proposes an application of symbolic analysis to beat-to-beat heart rate variability data derived from 24 h Holter recordings both in healthy and heart failure populations. Heart rate series are transformed in a sequence of six symbols via a uniform quantization procedure. Symbols are grouped in patterns lasting three cardiac cycles and these patterns are grouped in few (four) families without...
We computed 3 linear and 20 nonlinear HRV indexes on 24-h Holter recordings from 200 stable CHF patients (age 52plusmn9 yrs, NYHA II-III, LVEF 24plusmn6%) with the aim to assess i) the mutual interrelationships between these indexes and ii) their prognostic value towards cardiac death. We found high correlations between variables, with potential bias in fitting survival models. To overcome this problem...
Nonlinear analysis of HRV, particularly the fractal dimension and 1/f beta parameters, has been recognized to provide valuable information in the prognostic classification of cardiac patients. The reproducibility of these methods, however, is not known. In this study we addressed these issues in a population of chronic heart failure (CHF) patients. We analyzed 3 ECG Holter recordings from 22 clinically...
A 25 kV AC railway system is considered, where the variable length (10-20 km) section comprised between two electrical substations (ESSs) is equipped with audiofrequency track circuits (both transformer and s-bond coupled). The railway system is modelled using multiconductor transmission line (MTL) approach; the ESSs, the vehicle and the tuning unit of the track circuit are described by means of their...
Three patients affected by the congenital mono-ophthalmia syndrome were submitted to horizontal eye movements recording. The aim was to study the nystagmus and its characteristics, in order to give information that could explain signs and symptoms of the syndrome.Eye movements recording and analysis displayed a jerk nystagmus with a decreasing-velocity exponential slow phase, characteristic of a...
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