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The quality of our life is tied to the quality of our sleep. People with sleep deficits may experience impaired performance, irritability, lack of concentration, and daytime drowsiness. Increased mobility in bed can be a sign of disrupted sleep. Therefore, body movements in bed represent an important behavioral aspect of sleep. In this paper, we propose a method for detection and classification of...
Sleep studies are considered a paradigmatic example of the complex cardiorespiratory interactions, with an important impact also for clinical implications: diagnosis and treatment control, not only for the classical common sleep disturbances, but also for obstructive sleep apnea (OSA) or central apnea (CA) which are often associated with an increased risk of cardiovascular pathologies, such as hypertension,...
Studies suggest that obstructive sleep apnea syndrome (OSAS) is causally related to abnormal cardiovascular autonomic control in adults, but this has not been established in pediatric OSAS. The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular response abnormalities, in children with OSAS. During wakefulness, we continuously measured the ECG, arterial...
Wavelet entropy (WE), a new method of complexity measure for non-stationary signals, was used to investigate the dynamic features of rat EEGs under three vigilance states. The EEGs of the freely moving rats were recorded with implanted electrodes and were decomposed into four components of delta, theta, alpha and beta by using multi-resolution wavelet transform. Then, the wavelet entropy curves were...
We searched for possible associations between various measures of severity of sleep-disordered breathing (SDB) and indices of cardiac autonomic function in older subjects (>60 years). Twenty four overnight unattended home-based polysomnograms obtained from the Sleep Heart Health Study were analyzed using spectral analysis. For each subject, six autonomic indices reflecting heart rate variability...
This paper aimed at developing an index, called sleep index, to assess the quality of sleep in normal and obstructive sleep apnea (OSA) subjects. The sleep index was designed to be directly proportional to the summation of product of the number seconds spent in each stage of sleep and the selected weighting coefficient of each sleep stage. It was also inversely proportional to the product of total...
In patients suffering from various sleep disorders and some elderly patients, sleep is disturbed with frequent but brief arousal. These events do not cause behavioral awakening, but can lead to excessive day time sleepiness. These brief arousals or microarousals (MAs) can be identified on a standard polysomnogram as a transient abrupt change of frequency, typically in the alpha and extended beta (16-40...
On the body surface the electric field generated by the cardiac muscles consists of electric potential maxima and minima that increase and decrease during each cardiac cycle. The recording of these electric potentials as a function of time is called electrocardiography, and the resulting signal is called the electrocardiogram (ECG). The ECG signal is used extensively as a low cost diagnostic tool...
Sleep is a natural periodic state of rest for the body, in which the eyes usually close and consciousness is completely or partially lost. Consequently, there is a decrease in bodily movements and responsiveness to external stimuli. Slow wave sleep is of immense interest as it is the most restorative sleep stage during which the body recovers from weariness. During this sleep stage, electroencephalographic...
Spectral analysis was carried out on the R-wave attenuation (RWA) trend and heart rate variability (HRV) series, derived from the polysomnographic electrocardiogram (ECG) of the subjects with and without Cheyne Stokes breathing. Nocturnal polysomnography was performed on 16 normal subjects and 7 subjects with Cheyne Stokes breathing (CSB) patients. The polysomnographic ECG data was divided into fifteen...
Sleep apnea syndrome (SAS) is a very common sleep disorder disease. Reliable detection of apnea is very crucial for subsequent treatment. In this article, a novel method based on artificial neural network is proposed for such purpose. With its time-invariant property the time delay neural network (TDNN) is adopted in this system to employ the temporal trend of apnea event. As airflow and SaO take...
Obstructive sleep apnea (OSA) is a common breathing disorder among children with a prevalence estimated at 2-4%. Electrocardiography (ECG) based signal processing, especially heart rate analysis, demonstrated its promising future as both an alternative to other expensive portable sleep study methods and additional approach to sleep cardio-respiratory autonomic interactions which the current clinical...
The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes...
Several studies have shown differences in spectral parameters between simple snorers and patients with obstructive sleep apnea syndrome (OSAS). Most of them analyzed a reduced number of snores and/or only post-apneic snores were selected in OSAS patients. Previous findings suggest that snore parameters have a greater variability as the severity of OSAS increases. In this work we propose to analyze...
The goal of the project is to investigate new computational tools for understanding normal upper airway mechanics and the pathophysiology of obstructive sleep apnea (OSA), a disorder characterized by repetitive pharyngeal collapse and occlusion during sleep. To relate the airway mechanical parameters to anatomy, and explore the roles of primary muscle properties, airway shape and structure, a new...
Sleep disorders have a high prevalence. Sleep disorders are recognized first by the complaint of non-restorative sleep. A quantification of the disorder is done by the investigation in a sleep laboratory. The investigation in the sleep laboratory examines the EEG, EOG and EMG to derive sleep stages. This is a labor intensive sleep scoring after the polysomnography investigation. Usually the time course...
Frequent arousals during sleep degrade the quality of sleep and result in sleep fragmentation. Visual inspection of physiological signals to detect the arousal events is inconvenient and time-consuming work. The purpose of this study was to develop an automatic algorithm to detect the arousal events. We proposed the automatic method to detect arousals based on time-frequency analysis and the support...
A method for automatic detection of sleep apnea using pulse photoplethysmography signal (PPG) is proposed. This method is based on a detection of decreases on PPG amplitude fluctuations. The proposed detector is composed of three stages: pre-processing, envelope detection, based on root mean square series or Hilbert transform, and decision algorithm based on an adaptive threshold. The detector has...
It is said that sleep apnea syndrome is one of the main causes of airplane, train and car accidents. We have developed a non-contact breathing measurement system which diagnoses not only sleep apnea syndrome but also other sleep disorders. This system calculates the amount of the volume change and makes the movement of the outside of the body by the breath motion visible. If the patient is breathing...
Hypnotic drugs induced sleep is usually different from physiological sleep in restoring body energy. The cause of the differences is not clear. To investigate the differences between these two types of sleep, in this study, hypnotic drug diazepam (DZP) induced sleep was compared with the recovery sleep following sleep deprivation. Power spectral analysis was used to reveal the different EEG features...
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