Search Results
Results 201 - 250 of 643
< 1 2 3 4 5 6 7 8 9 10 >
Elghozi Jean-Luc - - 2007
The static relationship between heart rate (HR) and the activity of either vagal or sympathetic nerves is roughly linear within the physiological range of HR variations. The dynamic control of HR by autonomic nerves is characterized by a fixed time delay between the onset of changes in nerve activity and ...
Västfjäll Daniel - - 2007
This research aimed at validating two self-report composite rating scales of core affect that are useful when quick assessments are required, for instance, of current mood or recalled, anticipated, and experienced emotional reactions. The ratings were derived from the Swedish Core Affect Scales (SCAS) comprising six self-report rating scales of ...
Machowska-Majchrzak Agnieszka - - 2007
BACKGROUND AND PURPOSE: Accelerometric registration of tremor with the subsequent estimation of its parameters allows objective collection of information. The aim of the study was an analysis and visualization of the signal of the recorded tremor, including assessment of spectral components at the dominant frequency and selection of those parameters ...
Chan Hsiao-Lung - - 2007
Heart rate (HR) variability derived from electrocardiogram (ECG) can be used to assess the function of the autonomic nervous system. HR exhibits various characteristics during different physical activities attributed to the altered autonomic mediation, where it is also beneficial to reveal the autonomic shift in response to physical-activity change. In ...
Meunier Jason M - - 2007
Results of previous studies suggest that pacing strength stimuli can capture activation during ventricular arrhythmia locally near pacing sites. The existence of spatio-temporal distribution of excitable gap during arrhythmia suggests that multiple and timed stimuli delivered over a region may permit capture over larger areas. OBJECTIVE OF THE STUDY: Our ...
Shelly David R - - 2007
Non-volcanic tremor is a weak, extended duration seismic signal observed episodically on some major faults, often in conjunction with slow slip events. Such tremor may hold the key to understanding fundamental processes at the deep roots of faults, and could signal times of accelerated slip and hence increased seismic hazard. ...
Raethjen Jan - - 2007
Conflicting results on the existence of tremor-related cortical activity in essential tremor (ET) have raised questions on the role of the cortex in tremor generation. Here we attempt to address these issues. We recorded 64 channel surface EEGs and EMGs from forearm muscles in 15 patients with definite ET. EEG ...
Goedhart Annebet D - - 2007
The extent to which various measures of ambulatory respiratory sinus arrhythmia (RSA) capture the same information across conditions in different subjects remains unclear. In this study the root mean square of successive differences (RMSSD), peak valley RSA (pvRSA), and high frequency power (HF power) were assessed during ambulatory recording in ...
Floyd A G - - 2007
OBJECTIVE: To provide the first descriptive analysis of upper limb motor physiology in Niemann-Pick Type C disease (NP-C). METHODS: Fifteen patients with confirmed NP-C underwent motor physiology testing using accelerometry and surface EMG (sEMG). Tremor amplitude and frequency were quantified using accelerometry, and sEMG was examined for abnormal patterns consistent ...
Dromey Christopher - - 2008
The goal of this case study was to measure and describe differences between vocal vibrato and essential tremor of the voice in one individual who exhibited both types of modulation. Recordings of spoken and sung vowels produced by the same individual at three effort levels were examined via analysis of ...
Park Byung-Kwon BK Dept. of Electrical Engineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA. - - 2007
Continuous wave (CW) Doppler motion sensing radar can detect human physiological signal such as respiration or heart signals at a distance and through barriers. It has been shown that heart rate can be extracted with good accuracy for normally clothed subjects. Such technique could potentially be used to search for ...
Meste Olivier O Lab. I3S UNSA-CNRS, University of Nice-Sophia Antipolis, France. - - 2007
During exercise, analysis of the spectral components of the heart rate variability (i.e. R-R interval series variability; HRV) points out a new high frequency component related to the pedalling frequency. This component is independent of the classical low and high frequency bands related to the autonomic nervous system modulation of ...
Noh Yeon Sik YS Biomedical Engineering Department, Yonsei University, 234 maeji hyeongup, Wonju, Kangwon, Republic of Korea. - - 2007
Our study focuses on classifying as significant Electrocardiogram (ECG) data from home healthcare system. Generally, spectral analysis of RR Interval (RRI) time series is used to determine periodic component of Heart Rate Variability (HRV). It is well known, moreover, that Low Frequency (LF) component is associated with blood pressure regulation, ...
González-Landaeta R R Instrumentation, Sensors and Interface Group, Universitat Politècnica de Catalunya, Castelldefels, Barcelona, 08860, Spain. - - 2007
We propose a novel technique for heart rate detection on a subject that stands on a common electronic weighing scale. The detection relies on sensing force variations related to the blood acceleration in the aorta, works even if wearing footwear, and does not require any sensors attached to the body. ...
Bailon Raquel R Aragón Institute for Engineering Research, University of Zaragoza , María de Luna, 1, 50015 Zaragoza, Spain. - - 2007
In this paper a methodological approach for the analysis of nonstationary heart rate variability (HRV) signals using time-varying frequency bands based on respiratory frequency is presented. Spectral analysis of HRV is accomplished by means of the Smoothed Pseudo Wigner Ville distribution. Different approaches to the definition of the low frequency ...
Choi David Y DY Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA. - - 2007
This paper demonstrates tremor compensation for human subjects using an active handheld micromanipulator. This instrument uses optical and inertial sensing to detect its own motion, estimates tremor using linear filtering, and a flexure-based manipulator to actuate the tip. Compensation results while tracing a line with the tool are presented for ...
Li Huaming H Department of Electrical and Computer Engineering, Michigan Technological University, Houghton, MI 49931, - - 2007
In this paper, a body sensor network based ECG signal segmentation approach is presented. Hidden Markov Modeling (HMM) technique is employed. Since people's heart rates vary a lot, the corresponding characteristic waveform intervals and durations change with time as well. For patients with cardiac diseases, such as arrhythmia, the heart ...
Watanabe Hiroshi - - 2007
We studied the effects of the presentation of a visual sign that warned subjects of acceleration around the yaw and pitch axes in virtual reality (VR) on their heart rate variability. Synchronization of the immersive virtual reality equipment (CAVE) and motion base system generated a driving scene and provided subjects ...
Veluvolu K C KC School of Mechanical and Aerospace Engineering, Nanyang Technological University, Blk N3, Nanyang Ave, Singapore 639798. - - 2007
Surgical accuracy of the hand-held instruments depends on the active compensation of disturbance and tremor. Physiological tremor is one of the main causes for imprecision in micro-surgery procedures. One of the popular tremor compensation methods is based on weighted-frequency Fourier linear combiner (WFLC) algorithm, that can adapt to the changes ...
Kotani Kiyoshi - - 2007
OBJECTIVES: The objectives of this paper were to present a method to extract the amplitude of RSA in the respiratory-phase domain, to compare that with subjective or objective indices of the MWL (mental workload), and to compare that with a conventional frequency analysis in terms of its accuracy during a ...
Schwab K - - 2006
The heart rate variability (HRV) can be taken as an indicator of the coordination of the cardio-respiratory rhythms. Bispectral analysis using a direct (fast Fourier transform based) and time-invariant approach has shown the occurrence of a quadratic phase coupling (QPC) between a low-frequency (LF: 0.1 Hz) and a high-frequency (HF: ...
Kuncel Alexis M - - 2006
Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus for essential tremor is sometimes limited by side effects. The mechanisms by which DBS alleviates tremor or causes side effects are unclear; thus, it is difficult to select stimulus parameters that maximize the width of the therapeutic window. ...
Hennig Thomas - - 2006
The statistical properties of heart beat intervals of 130 long-term surface electrocardiogram recordings during atrial fibrillation (AF) are investigated. We find that the distribution of interbeat intervals exhibits a characteristic exponential tail, which is absent during sinus rhythm, as tested in a corresponding control study with 72 healthy persons. The ...
Denver John W JW University of Illinois at Chicago, The Brain-Body Center, Chicago, IL 60608, USA. - - 2007
Although respiratory sinus arrhythmia (RSA) is a commonly quantified physiological variable, the methods for quantification are not consistent. This manuscript questions the assumption that respiration frequency needs to be manipulated or monitored to generate an accurate measure of RSA amplitude. A review of recent papers is presented that contrast RSA ...
Miyamoto Hiroshi - - 2006
The heart of animals is regulated through the central nervous system in response to external sensory stimuli. We found, however, that the adult neurogenic heart of the isopod crustacean Ligia exotica has photosensitivity. The beat frequency of the isolated heart decreased in response to a light stimulus. Magnitude of the ...
Zhong Yuru - - 2006
Interactions among physiological mechanisms are abundant in biomedical signals, and they may exist to maintain efficient homeostasis. For example, sympathetic and parasympathetic neural activities interact to either elevate or depress the heart rate to maintain homeostasis. There has been considerable effort devoted to developing algorithms that can detect interactions between ...
Goosey-Tolfrey Victoria L - - 2006
The purpose of this study was to investigate the effect of different synchronous push strategies on physiological parameters and temporal timing characteristics. Eight novice male able-bodied participants completed four counter-balanced conditions: two push strategies (constant pushing) and intermittent pushing (INT) at two push frequencies (40 and 70 pushes/min) at 27 ...
Ouchi Yasuomi - - 2006
To investigate changes in regional cerebral blood flow (rCBF) under the prone condition with and without light massage on the back, we measured rCBF quantitatively in healthy human subjects using positron emission tomography with H(2)15O. Biochemical tests showed that the light massage (palm-pressure) reduced levels of stress-related serum cortisol and ...
Cysarz Dirk - - 2007
The human heartbeat series is more variable and, hence, more complex in healthy subjects than in congestive heart failure (CHF) patients. However, little is known about the complexity of the heart rate variations on a beat-to-beat basis. We present an analysis based on symbolic dynamics that focuses on the dynamic ...
Ushe Mwiza - - 2006
Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) reduces tremor in people with essential tremor (ET), yet the dependence of tremor suppression on stimulation frequency remains unclear. To address this issue, we tested tremor suppression for three 15-second measurements during a variety of stimulation frequencies in 11 ET ...
Shelly David R - - 2006
Non-volcanic seismic tremor was discovered in the Nankai trough subduction zone in southwest Japan and subsequently identified in the Cascadia subduction zone. In both locations, tremor is observed to coincide temporally with large, slow slip events on the plate interface downdip of the seismogenic zone. The relationship between tremor and ...
Marchenko Vitaliy - - 2006
Respiratory motor outputs contain medium-(MFO) and high-frequency oscillations (HFO) that are much faster than the fundamental breathing rhythm. However, the associated changes in power spectral characteristics of the major respiratory outputs in unanesthetized animals during the transition from normal eupneic breathing to hypoxic gasping have not been well characterized. Experiments ...
Farshchi Shahin - - 2006
Existing approaches used to develop compact low-power multichannel wireless neural recording systems range from creating custom-integrated circuits to assembling commercial-off-the-shelf (COTS) PC-based components. Custom-integrated-circuit designs yield extremely compact and low-power devices at the expense of high development and upgrade costs and turn-around times, while assembling COTS-PC-technology yields high performance at ...
Wang Shouyan - - 2006
OBJECTIVE: To differentiate physiological from harmonic components in coherence analysis of the tremor-related neural and muscular signals by comparing power, cross-power and coherence spectra. METHODS: Influences of waveform, burst-width and additional noise on generating harmonic peaks in the power, cross-power and coherence spectra were studied using simulated signals. The local ...
Jun Woo Cheol - - 2006
We propose an approach for analyzing the basic relation between correlation properties of the original signal and its magnitude fluctuations by decomposing the original signal into its positive and negative fluctuation components. We use this relation to understand the following phenomenon found in many naturally occurring time series: the magnitude ...
Birn Rasmus M - - 2006
Subtle changes in a subject's breathing rate or depth, which occur naturally during rest at low frequencies (<0.1 Hz), have been shown to be significantly correlated with fMRI signal changes throughout gray matter and near large vessels. The goal of this study was to investigate the impact of these low-frequency ...
Tadros Rafik - - 2006
BACKGROUND: Rate-dependent nodal properties are commonly assessed with premature protocols performed at different basic rates. Because characteristics of responses differ with recovery time index, the true nature of nodal rate-dependent properties is elusive. OBJECTIVES: The purpose of this study was to reveal consistent nodal rate-dependent properties regardless of selected recovery ...
Legros Alexandre - - 2006
It is becoming important to specify the smallest effects of extremely low frequency (ELF) magnetic fields (MF) on human physiology. One difficulty is that some people seem more sensitive and more responsive than others to MF exposure. Consequently, within- and between-subject differences have to be taken into account when evaluating ...
Bolnick Jay M - - 2006
OBJECTIVE: The purpose of this study was to compare the effect of halogen light and vibroacoustic stimulation on fetal heart rate (FHR) responsiveness and on nonstress test (NST) results. METHODS: Sixty consecutively-chosen patients between 33 and 39 weeks of gestation underwent an NST on at least three weekly occasions. Each ...
Hwang I S - - 2006
To investigate change in coordinative strategies due to wrist immobilization and index loading, postural tremors from the index, hand, and forearm were recorded during different postural holding tasks. The wrist joint was immobilized with a thermoplastic splint in the constrained condition, and a copper mass of 100 grams was applied ...
Gonçalves Hernâni - - 2006
The effect of foetal heart rate (FHR) acquisition mode on linear and nonlinear parameters is still largely unknown. In 33 normal labouring women, FHR signals were acquired simultaneously by an external ultrasound sensor applied to the maternal abdomen and an internal scalp electrode, in the minutes preceding delivery. For each ...
Campbell H A - - 2006
Power spectral analysis (PSA) provides a powerful tool for determining frequency oscillations in time signals, and it is accepted that mammals can show distinct components in the heart rate (fH) spectrum that are synchronous with ventilatory frequency (fV). Using similar signal processing techniques, these fundamental components at fV are not ...
Rocon E E Instituto de Automática Industrial, Spain. - - 2006
This paper introduces the Hilbert Analysis (HA), which is a novel digital signal processing technique, for the investigation of tremor. The HA is formed by two complementary tools, i.e. the Empirical Mode Decomposition (EMD) and the Hilbert Spectrum (HS). In this work we show that the EMD can automatically detect ...
Goren Yael - - 2006
Heart rate variability (HRV) is a major noninvasive technique for evaluating the autonomic nervous system (ANS). Use of time-frequency approach to analyze HRV allows investigating the ANS behavior from the power integrals, as a function of time, in both steady-state and non steady-state. Power integrals are examined mainly in the ...
Thong Tran T Dept. of Biomed. Eng., Oregon Health & Sci. Univ., Beaverton, OR 97006, USA. - - 2006
The most common spectral indices of heart rate variability are the powers in the high frequency (HF), low frequency (LF) and very low frequency (VLF) bands. These indices have typically been computed using Fourier transforms. In this paper we propose a multirate filtering approach that does not require that the ...
Shin Kunsoo K Interaction Lab, Samsung Adv. Inst. of Technol., Suwon, Korea. - - 2006
In this paper, we investigated the validity of the WHAM (wearable heart activity monitor) in the clinical applications, which has been implemented as a wearable ambulatory device for continuously and long-term monitoring user's cardiac conditions. To this end, using the WHAM and the conventional Holter monitor the ECG signals over ...
Zhong Yuru Y Dept. of Biomed. Eng., State Univ. of New York, Stony Brook, NY, - - 2006
Interactions among physiological mechanisms are abundant in biomedical signals, and they may exist to maintain efficient homeostasis. For example, sympathetic and parasympathetic neural activities interact to either elevate or depress the heart rate, to maintain homeostasis. There has been considerable effort devoted to developing algorithms that can detect interactions between ...
Lanata A A Interdept. Res. Centre E. Piaggio, Pisa Univ, Pisa, Italy. - - 2006
In this paper we report on results from experiments performed on a bi-modal piezoelectric transducer used both as an active ultrasound transceiver and a passive acoustic sensor. The transducer, which has a low Q factor in order to exhibit a sufficiently broad bandwidth, will be integrated into a wearable system. ...
Watanabe Kajiro - - 2005
We have developed a noninvasive pneumatics-based system by which to measure heartbeat, respiration, snoring, and body movements of a subject in bed. A thin, air-sealed cushion is placed under the bed mattress of the subject and the small movements attributable to human automatic vital functions are measured as changes in ...
Hori Kiyokazu - - 2005
The effects of acoustic and visual stimuli and their synergistic effects on heart rate variability including gender differences were investigated. Of particular interest was the influence of visual stimulus on heart rate variability during listening to simple sounds of different characters. Twelve male and 12 female university students were selected ...
< 1 2 3 4 5 6 7 8 9 10 >