Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains viii, 195 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 77-81).

Thesis (doctoral)--Freie Universität Berlin, 1980.

One of two project reports. The other is designated PART A: McMASTER (ON-CAMPUS) PROJECT / <p> It is well known that heart rate is an important physiological parameter. In some cases, continuous monitoring of active subjects is desireable. </p> <p> The report focuses on the feasibility of a miniaturized, portable heart rate monitor. Good artifact rejections, low power consumption small size and ease of use are of primary importance in such design. In order to keep size as low as possible a single cell (1 .5 V) supply voltage is used. </p> <p> A LED - phototransistor type of transducer was chosen for its good artifact rejection and simplicity of application. The transducer clips on the subject's earlobe. Light transmitted through the earlobe is amplitude modulated by the heart (blood) pulses and detected by the phototransistor thus providing electrical signal. </p> <p> In order to keep current drain low, the LED was powered by ~ 1% duty cycle pulses. The rest of the system was designed to comply with the requirements of the transducer. The detected train of pulses were preamplified and the original modulating waveform (heart pulse) reconstructed by a "sample and hold" circuit. The reconstructed signal was amplified by a narrow-band-pass amplifier filter. </p> <p> An astable and two monostable multivibrators perform the necessary timing. Two integrated circuits were also employed: a voltage regulator, to provide stable reference voltages where needed and the output amplifier filter, providing the bulk of the gain. </p> <p> A working prototype was built and suggests that a personalized heart rate monitor is quite feasible. The whole circuit can be integrated, with the exception of few capacitors and perhaps some trimming potentiometers. </p> / Thesis / Master of Engineering (MEngr)

An emerging diagnostic tool for detecting heart and physiological conditions is heart rate variability (HRV). Copious research continuously discovers relationships between heart rate variability metrics and physiological functions and cardiac health. The first step in calculating HRV metrics is calculating heart rate. Heart rate is typically calculated using the interval between R peaks in an EKG signal. Consequently, heart rate measurements rely on the presence of distinctive R peaks and the accurate detection of them. The study is motivated by the drawbacks associated with using R peaks to calculate instantaneous heart rate. In this study we present an alternative method (that does not rely on R peaks) based on the concept of instantaneous frequency to estimate heart rate from electrocardiogram (EKG) signals. The EKG signal is filtered to extract constituent frequency components that correlate with the instantaneous heart rate. The filtered signal is then fed into an algorithm that outputs a signal that shows the variation of the instantaneous heart rate with time. This output signal contains noise due to the behavior of the algorithm at zero crossings of the filtered EKG signal. Two methods for filtering the output signal are also presented in the study. The proposed method was able to successfully estimate the instantaneous heart rate and allowed the subsequent calculation of frequency domain HRV metrics. This method potentially provides more information for HRV analysis and addresses the drawbacks associated with methods based on R peak detection. / Master of Science / Heart disease is the leading cause of death in America accounting for about 20% of all deaths. Consequently, both the public and the medical community are engrossed in cardiovascular health, research that enables early detection of heart disease and novel treatments for cardiac conditions. An emerging diagnostic tool for detecting heart and physiological conditions is heart rate variability (HRV). Copious research continuously discovers relationships between heart rate variability metrics and physiological functions and cardiac health. The first step in calculating HRV metrics is calculating heart rate. With the rise in popularity and improvement of wearable technologies, it has become easier than ever to collect data and perform diagnostics, often in real time. As such the need for robust methods and algorithms to perform these calculations are ever more important. The study is motivated by drawbacks associated with the conventional method used to calculate heart rate from electrocardiogram signals. In this study we present a more robust method to calculate heart rate from EKG signals allowing more accurate HRV metrics to be calculated. In this study we present an alternative method based on the concept of instantaneous frequency to estimate heart rate from electrocardiogram (EKG) signals. We identify the shortcomings of the conventional method of estimating heart rate and discuss the strengths and weaknesses of the alternative method introduced. We then calculate and compare the HRV metrics calculated from the proposed method and the conventional method. The method presented also has the potential to be used on other signals that measure the heart's activity such as Photoplethysmography signals (PPG) allowing it to be used on wearable devices. We hope that the information provided, and the findings presented in this study will be utilized by the medical community and researchers for future research related to heart rate variability.

The current study aimed to test sensation seeking as a mediator in the relationship between arousal and aggression. In addition, an experimental design was used to test whether arousal can be manipulated to alter levels of sensation seeking and aggression, both measured behaviorally. A sample of 128 undergraduate students completed state and trait measures of sensation seeking and aggression, and baseline measures of physiology. It was hypothesized that trait sensation seeking would mediate the relationship between baseline physiology and trait aggression. Also, state sensation seeking would mediate the relationship between an arousal manipulation and state aggression. The results failed to support the proposed mediation models. Furthermore, the arousal manipulation was insufficient to result in sustained heart rate differences, and therefore the malleability of state sensation seeking and aggression could not truly be tested. Exploratory analyses supported an interaction between arousal and sensation seeking, such that in individuals low on experience seeking, disinhibition and boredom susceptibility, low heart rate was associated with greater aggression. These findings suggest that arousal and sensation seeking may conjointly predict aggression through moderation rather than mediation, though future studies with improved experimental designs are needed. / Ph. D.

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Via the delivery of blood, heart transfers oxygen and nutrients to various organs and is thus a highly influential for circulatory system. To adapt to the variation of physiological conditions, the intensity and frequency of heart beats change with time. Careful observation finds that the time intervals between heartbeats are often different even if the body is at rest. Such heart rate variability (HRV) has been used to estimate the activity of the autonomic nervous system which can be divided into sympathetic and parasympathetic subsystems both of which can significantly affect the physiology of the human body. As a result, HRV has been used as a physiological indicator to assist doctors in making diagnostic decisions. Many studies have used HRV to analyze the ECG signal via studying the QRS complex waveform to determine the time intervals between R-peaks and analyze the R-R intervals from time and frequency domains. Different from the conventional R-R Interval based approach, this work introduces new HRV feature variables by computing spectrogram of the ECG signal waveform. In particular, based on the harmonics of the spectrum, we introduce the concepts of modes. By find the relative amount of energy associated with each mode and degree-of-energy-concentration associated with each mode, this work introduces two sets of new HRV features. In addition, we also investigate how these variables change with time and the correlations between these features. To demonstrate the potential of the proposed features, the differences of the values of the proposed features are compared for healthy individuals versus OSA patients, young versus old and male versus female. The experimental results show the differences between many of the tested features are statistically significant.

Measuring physiological parameters or vital sign using camera has become popular in recent years. Contact-less monitoring and extraction of vital signs can be important source of information in situations like medical care system and safety control system. This paper presents the implementation of real-time, non-contact method for extraction of vital signs, heart rate in this case. A better face tracking method is used for efficient face detection. This study extends some of the previous works done and have a comparison study with several methods. The developed system used filtering with window over the green channel of the signal and then Converted to frequency domain to analyze the signal to detect heart rate. The developed system achieved high correlation and showed small error while referencing with actual heart signal from ECG. This method delivers better result in better light condition but gives fairly good result on lower light as well.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 92-96). / 111 leaves, bound ill. (some col.) 29 cm

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 78-82). / xiii, 82 leaves, bound ill. 29 cm