ECG), Electroencephalogram Research Articles

Sleep-Related Arousal Versus General Cognitive Arousal in Primary Insomnia

The present study aimed at further investigating trait aspects of sleep-related cognitive arousal and general cognitive arousal and their association with both objective and subjective sleep parameters in primary insomnia patients. A clinical sample of 182 primary insomnia patients and 54 healthy controls was investigated using 2 nights of polysomnography, subjective sleep variables, and a questionnaire on sleep-related and general cognitive arousal. Compared to healthy controls, primary insomnia patients showed both more sleep-related and general cognitive arousal. Furthermore, sleep-related cognitive arousal was closely associated with measures of sleep-onset and sleep-maintenance problems, while general cognitive arousal was not. Cognitive-behavioral treatment for insomnia might benefit from dedicating more effort to psychological interventions that are able to reduce sleep-related cognitive arousal.

A portable wireless biometric multi-channel system

This article presents an 8-channel system for capturing bioelectric signals and transmitting them by the ZigBee protocol. It is a small, portable system with optimised power supply so that it can be battery fed. One of its main advantages is its versatility, since it enables each channel to be configured, in a dynamic and individualised way. This makes it possible to capture diverse bioelectric signals simultaneously, such as electrocardiogram (ECG), electroencephalogram (EEG), electrooculogram (EOG), etc. The developed system can be easily integrated into a Wireless Sensor Network based on ZigBee technology.

Wavelet diagnosis of ECG signals with kaiser based noise diminution

The evaluation of distortion diagnosis using Wavelet function for Electrocardiogram (ECG), Electroencephalogram (EEG) and Phonocardiography (PCG) is not novel. However, some of the technological and economic issues remain challenging. The work in this paper is focusing on the reduction of the noise interferences and analyzes different kinds of ECG signals. Furthermore, a physiological monitoring system with a programming model for the filtration of ECG is presented. Kaiser based Finite Impulse Response (FIR) filter is used for noise reduction and identification of R peaks based on Peak Detection Algorithm (PDA). Two approaches are implemented for detecting the R peaks; Amplitude Threshold Value (ATV) and Peak Prediction Technique (PPT). Daubechies wavelet transform is applied to analyze the ECG of driver under stress, arrhythmia and sudden cardiac arrest signals. From the obtained results, it was found that the PPT is an effective and efficient technique in detecting the R peaks compared to ATV.

Pretreatment with human serum butyrylcholinesterase alone prevents cardiac abnormalities, seizures, and death in Göttingen minipigs exposed to sarin vapor

Human serum butyrylcholinesterase (Hu BChE) is a stoichiometric bioscavenger that is being developed as a prophylactic countermeasure against organophosphorus nerve agents. This study was designed to evaluate the efficacy of Hu BChE against whole-body inhalation exposure to a lethal dose of sarin (GB) vapor. Male Göttingen minipigs were subjected to: air exposure, GB vapor exposure, or pretreatment with Hu BChE followed by GB vapor exposure. Hu BChE was administered by i.m. injection 24h prior to exposure to 4.1mg/m3 of GB vapor for 60min. Electrocardiograms (ECG), electroencephalograms (EEG), and pupil size were recorded throughout exposure. Blood drawn before and throughout exposure was analyzed for blood gases, electrolytes, metabolites, acetylcholinesterase and BChE activities, and amount of GB present. Untreated animals exposed to GB vapor exhibited cardiac abnormalities and generalized seizures, ultimately succumbing to respiratory failure. Pretreatment with 3.0 or 6.5mg/kg of Hu BChE delayed blood gas and acid–base disturbances and the onset of cardiac and neural toxic signs, but failed to increase survivability. Pretreatment with 7.5mg/kg of Hu BChE, however, completely prevented toxic signs, with blood chemistry and ECG and EEG parameters indistinguishable from control during and after GB exposure. GB bound in plasma was 200-fold higher than plasma from pigs that did not receive Hu BChE, suggesting that Hu BChE scavenged GB in blood and prevented it from reaching other tissues. Thus, prophylaxis with Hu BChE alone not only increased survivability, but also prevented cardiac abnormalities and neural toxicity in minipigs exposed to a lethal dose of GB vapor.

Analysis of human PPG, ECG and EEG signals by eigenvector methods

This paper presents eigenvector methods for analysis of the photoplethysmogram (PPG), electrocardiogram (ECG), electroencephalogram (EEG) signals recorded in order to examine the effects of pulsed electromagnetic field (PEMF) at extremely low frequency (ELF) upon the human electrophysiological signal behavior. The features representing the PPG, ECG, EEG signals were obtained by using the eigenvector methods. In addition to this, the problem of selecting relevant features among the features available for the purpose of discrimination of the signals was dealt with. Some conclusions were drawn concerning the efficiency of the eigenvector methods as a feature extraction method used for representing the signals under study.

AR Spectral Analysis Technique for Human PPG, ECG and EEG Signals

In this study, Fast Fourier transform (FFT) and autoregressive (AR) methods were selected for processing the photoplethysmogram (PPG), electrocardiogram (ECG), electroencephalogram (EEG) signals recorded in order to examine the effects of pulsed electromagnetic field (PEMF) at extremely low frequency (ELF) upon the human electrophysiological signal behavior. The parameters in the autoregressive (AR) method were found by using the least squares method. The power spectra of the PPG, ECG, and EEG signals were obtained by using these spectral analysis techniques. These power spectra were then used to compare the applied methods in terms of their frequency resolution and the effects in extraction of the features representing the PPG, ECG, and EEG signals. Some conclusions were drawn concerning the efficiency of the FFT and least squares AR methods as feature extraction methods used for representing the signals under study.

EMG-based analysis of change in muscle activity during simulated driving

Summary Extensive usage of computers could cause fatigue and even lead to musculo-skeletal injuries. Onset of fatigue can be determined by analyzing biosignals like surface electromyogram (sEMG), electrocardiogram (ECG), electroencephalogram (EEG) and electrooculogram (EOG). Physiological parameters such as pressure, respiration rate and oxygen debt have also been used to estimate the onset of fatigue and recovery time. Other than these measures, behavioral analysis using video and subjective analysis have also been used extensively to detect onset of fatigue. In this study, muscle activity changes in the shoulder and neck muscles while gaming in an automobile simulator, using sEMG, are analyzed. Two groups of professional and non-professional drivers participated in this study. Statistically significant (p

DESIGNING LOW POWER OF SIGMA DELTA MODULATOR FOR BIOMEDICAL APPLICATION

This paper discusses the design of micro power Sigma-delta modulator with oversampling technology. This Sigma-delta modulator design is paid special attention to its low power application of portable electronic system in digitizing biomedical signals such as Electro-cardiogram (ECG), Electroencephalogram (EEG) etc. [1]. A high performance, low power second order Sigma-delta modulator is more useful in analog signal acquisition system. Using Sigma-delta modulator can reduce the power consumption and cost in the whole system. The original biomedical signal can be reconstructed by simply applying the digital bit stream from the modulator output through a low-pass filter. The loop filter of this modulator has been implemented by using switch capacitor (SC) integrators and using simple circuitry consists of OpAmps, Comparator and DAC. In general, the resolution of modulator is about 10 bits for biomedical application. In this two order Sigma-delta modulator simulation results of the 1.8V sigma delta modulator show a 68 dB signal-to-noise-and-distortion ratio (SNDR) in 4 kHz biomedical signal bandwidth and a sampling frequency equal to 1 MHz in the 0.18 μ m CMOS technology. The power consumption is 400 μ W. It is very suitable for low power application of biomedical instrument design.

Clonidine Pretreatment Reduces the Systemic Toxicity of Intravenous Bupivacaine in Rats

Clonidine prolongs the duration of sensory and motor block induced by bupivacaine, and this association, in constant infusion by the epidural route, is used for postoperative analgesia. After a near-fatal intravenous bolus of bupivacaine in dogs, clonidine improves ventricular electrophysiologic parameters, but probably worsens bupivacaine-induced bradycardia and depression of the myocardial contractility. The current study, using a rodent animal model, evaluated the influence of clonidine pretreatment on the systemic toxic effects of bupivacaine overdose induced by a constant intravenous infusion. Twenty Wistar male rats were anesthetized with thiopental, and controlled ventilation was started with an equal mixture of O2 and N2O. Electrocardiogram (ECG), electroencephalogram (EEG), and invasive arterial blood pressure were continuously recorded. Clonidine (5 micrograms/kg) or saline was injected intravenously in a randomized fashion. After 15 min, an intravenous infusion of bupivacaine was started at 2 mg.kg-1 x min-1. The time of occurrence of the bupivacaine-induced toxic events was recorded and the doses were calculated. Ten (five in each group) additional rats, pretreated according to the same protocol, were killed at the time of the first dysrhythmia, for blood sampling and plasma bupivacaine concentration measurement. Clonidine reduced heart rate and arterial blood pressure before bupivacaine infusion (P < 0.05). The threshold doses at the first QRS modification (11.3 +/- 5.6 vs. 2.1 +/- 0.9 mg/kg) and the first dysrhythmia (40.6 +/- 15.3 vs. 8.48 +/- 3.7 mg/kg), the increase in EEG total spectral power (33.3 +/- 21.9 vs. 8.2 +/- 5.1 mg/kg), the 25 and 50% reduction in baseline mean arterial pressure and heart rate, the isoelectric EEG (58.6 +/- 14 vs. 22 +/- 6.6 mg/kg), and the final systole (99 +/- 16 vs. 51.8 +/- 14.5 mg/kg) were significantly greater in the clonidine group than in the saline group (P < 0.01). The time between the first dysrhythmia and 50% reduction of baseline mean arterial blood pressure was not different between the groups. In the additional series, the first dysrhythmia occurred later (10.9 +/- 4.5 vs. 3.2 +/- 1.0 min, P < 0.01) and plasma bupivacaine levels were greater (18.7 +/- 8.0 vs. 7.8 +/- 3.2 micrograms/ml, P < 0.01) in the clonidine group than in the saline group. In this model, clonidine given prophylactically delays the toxic manifestations of bupivacaine overdose and does not accentuate the subsequent hypotension.

Femoral Neck Fracture

A total of 427 elderly patients with femoral neck fractures were studied retrospectively to identify factors that may be correlated with life expectancy and functional prognosis. Gender, age, prefracture activities of daily living (ADL), electrocardiogram ECG), electroencephalogram (EEG), cognitive function, hemoglobin level, total protein level, and type of fracture were evaluated to determine the correlation of each predictive factor with survival time after surgery and three-month postoperative walking recovery rate. The one-year survival rate was found to be 55.9%: 59.1% for women and 52.3% for men. The walking recovery rate was 55.8%. The most important factors affecting life expectancy were prefracture ADL, ECG, EEG, and cognitive function score (Hasegawa's score). Electroencephalogram and Hasegawa's score also were found to be important prognostic factors for postoperative ADL. Preoperative medical conditions are useful indicators for determination of functional prognosis and survival.

The course of respiration and circulation in death due to typical hanging.

Experiments were carried out on 15 dogs to investigate the course of respiration and circulation during the agonal period of death due to typical hanging. Animals were asphyxiated by a method simulating typical hanging. Electrocardiogram (ECG), electroencephalogram (EEG), blood pressure (BP) in the femoral artery and intrathoracic pressure (ITP) were registered. In typical hanging, the course of respiration was characterized by shorter stages of dyspnoea and initial apnoea and a longer stage of the terminal respiration when compared with obstructive asphyxia. However, the whole time of the course of respiration and circulation in typical hanging was almost the same as that in obstructive asphyxia. The BP increased rapidly, was maintained during the dyspnoea stage, and then decreased gradually. EEG disappeared with, or a short time after, the end of the dyspnoea stage. The increased heart rate in the dyspnoea stage remained until circulatory collapse. The analysis of the ECG complexes revealed that the heart muscle adapted to oxygen deficiency during typical hanging.

Autoresuscitation: a survival mechanism in piglets.

Piglets were studied to determine 1) the cardiovascular and neurophysiological effects of prolonged laryngeal-induced respiratory inhibition (n = 7) and 2) whether these effects were modulated by autonomic blockade (n = 6). Respiration, electrocardiogram, electroencephalogram (EEG), and blood pressure were recorded, and blood gases were measured. During continuous laryngeal stimulation in the presence of light anesthesia, apnea was interrupted every 1-2.5 min by clusters of two to six breaths. Compared with control, these breaths had a significantly greater tidal volume (430 +/- 30% of control), shorter inspiratory time (87 +/- 5%), and longer expiratory time (124 +/- 15%) and, thus, were of a gasping nature. With each cluster of gasps, arterial PO2 increased from 15 +/- 2 to 56 +/- 5 Torr, heart rate from 84 +/- 7 to 161 +/- 5 beats/min, and mean blood pressure from 48 +/- 4 to 106 +/- 6 mmHg. The EEG became flat by 1 min after the onset of apnea and remained isoelectric throughout the stimulus period. Cyclical gasps were not affected by sympathetic or parasympathetic blockade. These data show that, despite EEG silence, piglets can autoresuscitate by initiating gasps that are not dependent on autonomic integrity. These gasps markedly improve cardiovascular status and may sustain animals for a prolonged period of time.

The course of respiration and circulation in ‘toluene-sniffing’

To investigate the course of respiration and circulation in death by toluene inhalation, 25 dogs were allowed to rebreathe toluene vapor in a 1-1 plastic bag expanded with air, and electrocardiogram (ECG), electroencephalogram (EEG), blood pressure (BP) in the femoral artery and intrathoracic pressure (ITP) were registered. The respiratory movement continued two times longer than that of death by suffocation using a plastic bag of the same size. In the ECG, low voltage of R waves precipitously appeared several minutes after the beginning of the experiment and continued. The BP gradually reduced by half and kept the level for several minutes. The stage was considered toluene narcosis. Toward the end of the respiratory movement, the BP increased gradually. The analysis of the ECG complexes during the toluene inhalation revealed the direct effect of toluene to the septal and ventricular muscle of the heart. But in the end of the respiratory movement, it revealed ST segment elevation and upright T. In a few experimental animals, some of the transient arrhythmia with fluctuation of the BP appeared during the course, and in one of these dogs, fatal ventricular fibrillation occurred suddenly. These findings suggested that in most cases of sudden death in ‘toluene-sniffing’, the cause of death is severe hypoxia during toluene narcosis, but in a few cases, it is fatal arrhythmia due to the direct effect of toluene to the heart muscle.

CSF zinc in Alzheimer's type dementia

Thirty-four patients (18 men, 16 women, age range 40-80 years) with primary degenerative dementia, diagnosed by DSM-III (American Psychiatric Association 1980) criteria, were studied. All patients underwent thorough examination that included electrocardiogram (ECG) , electroencephalogram (EEG) , computed tomogram (CT), chest x-ray, blood count, serum electrolytes, blood urea and sugar, urine analysis, liver function tests, serological tests for syphilis, etc., which were designed to rule out any diseases that could cause or contribute to the dementia. The control population consisted of 34 age-matched, nonneurological and nonpsychiatric patients (25 men and 9 women). After informed consent, lumbar puncture was