The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Heart rate, heart rate variability (HRV), and respiratory effort have been proposed in numerous studies with the goal of correlating physiological parameters with mental workload. Aim of this study was to analyze the cardio-respiratory response to a mental task (Sternberg Task) from a single lead ambulatory ECG recording, in healthy subjects. Under no assumptions on stationarity, HRV was analyzed...
Sleepiness is a main causal factor for accidents and daytime malfunction. In this study we checked the feasibility of a new, ECG based method to detect the propensity to fall asleep while driving, using a passive Maintenance of Wakefulness Test (MWT) and an active Driving Simulation (DS) during increasing sleep deprivation conditions. Microsleeps (MS), and falling asleep (FA) events, were detected...
Spectral components of cardiovascular oscillations are related to complex autonomic control mechanisms. Since these oscillations are non-stationary, time-frequency (T-F) analysis has been used in studying cardiovascular oscillations such as variabilities of heart rate and blood pressure; however, few studies have extended the T-F analysis to other cardiovascular signals such as pulse transit time...
Spectral analysis of Heart Rate Variability (HRV) can be used for the assessment of cardiovascular autonomic control. In this study Smoothed-Pseudo Wigner-Ville Distribution (SPWVD) has been used to evaluate the effect of local anesthesia on HRV parameters in a group of fourteen patients undergoing brachial plexus block (local anesthesia) using the transarterial technique. Instead of using the fixed...
Detection of obstructive sleep apnea can be performed through heart rate variability analysis, since fluctuations of oxygen saturation in blood cause variations in the heart rate. Such variations in heart rate can be assessed by means of time-frequency analysis implemented with time-frequency distributions belonging to Cohen's class. In this work, dynamic features are extracted from time frequency...
It has been shown that a pedaling frequency component can be extracted from the heart rate variability (HRV) signal using a time-varying filter. It is shown that this filter can be implemented directly in the time-frequency plane with different approaches. The need of resampling the data is also discussed with regard to the artifacts produced when the Shanon condition is not fulfilled. In order to...
The aim of this study is to detect the ischemia-induced changes of heart rate variability (HRV) indices based on time-frequency analysis and to investigate the patterns of change when the duration of ischemia is concerned.
A parametric decomposition of the smoothed Wigner-Ville distribution is applied to estimate the instantaneous frequency and amplitude of the LF and HF components of HRV during stress testing. It is assumed that the instantaneous frequencies of the LF and HF components may vary linearly with time during stress testing, and that the frequency of the HF component can be approximated by the respiratory...
Arousal from sleep is a normal physiologic event during normal sleep, which produces a tachycardia-bradycardia pattern on the heart rate variability (HRV) signal, which testifies the involvement of the autonomic nervous system related to a central nervous system event. Repetitive arousals may be associated to excessive sleep fragmentation (for example in respiratory pathologies such as obstructive...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.