Similar to how electrocardiographic waves are the pace making signals of the heart, slow waves are the pace making signals of the intestines. Slow waves are electrical signals in the intestines that determine the speed at which food can move through the intestine ensuring proper digestion and uptake of nutrients. It has been shown that slow waves can be measured in adults using non-invasive, surface electrodes. However, no study has investigated the measurements of slow waves in neonates, specifically pre-term neonates. Around 7% of pre-term neonates suffer from necrotizing enterocolitis (NEC) which is a condition that causes damage to the intestinal tract and often death of intestinal tissue. NEC affects around 9,000 neonates each year with a survival rate estimated to be between 60%-80%. Currently, there are no non-invasive, early-stage indicators of NEC. This pilot study aims to create a non-invasive measurement setup to measure and characterize slow wave activity in neonates.

No description available.

Stretch is known to result in an electrically less stable ventricular substrate, yet the reported effects of stretch on measured electrophysiological parameters have been inconsistent and even contradictory. The goal of this study was to evaluate the effects of acute mechanical stretch on cardiac electrical features thought to be key in generation of arrhythmia, namely restitution of action potential duration (APD), electrical memory, and onset of alternans. Microelectrodes were used to record intracellular potentials pre, during, and post-stretch from isolated right ventricular tissues from swine. In separate experiments, the effects of two levels of stretch were quantified. Pacing protocols employing explicit diastolic interval (DI) control and cycle length (CL) control were used to obtain measures of restitution of APD, memory, and alternans of APD. Stretching the tissue had varying effects on APD, restitution and memory. Stretch increased APD, restitution slopes and memory by as much as 24, 30 and 53 % in some cases, while it decreased these by up to 18, 37 and 81 % in others. During stretch, alternans of APD were observed in some cases, which occurred at slower rates of activation than before stretch. Histology of tissue samples showed localized changes in orientation of cells relative to the direction of stretch. Our results show that among individual trials, stretch altered the measured electrophysiological properties, sometimes markedly. However, when pooled together, these changes cancelled each other and the averages showed no statistically significant difference after stretch. A potential mechanism that explains this divergent and inconsistent response to stretch is the presence of local, micron level, variation in orientation of myocytes. Upon stretch, these divergent effects likely increase dispersion of repolarization diffusely and might thus be the reason behind the consistently observed increase in arrhythmic substrate after stretch.

It is widely understood that neurons within the brain produce electrical activity, and electroencephalography—a technique used to measure biopotentials with electrodes placed upon the scalp—has been used to observe it. Today, scientists and engineers work to interface these electrical neural signals with computers and machines through the field of Brain-Computer Interfacing (BCI). BCI systems have the potential to greatly improve the quality of life of physically handicapped individuals by replacing or assisting missing or debilitated motor functions. This research thus aims to further improve the efficacy of the BCI based assistive technologies used to aid physically disabled individuals. This study deals with the testing and modification of a BCI system that uses the alpha and beta bands to detect motor intention by weighing online EEG output against a calibrated threshold.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Abstract There is a need in medicine and research for noninvasive, painless, safe and simple bed-side techniques to measure physiological processes associated with muscle function and activity. Bioelectrical Impedance Analysis (BIA) is a widely used, noninvasive, painless, safe and simple procedure for the measurement of body composition. However, although capable of producing accurate and reproducible data, it is known to be prone to movement artifacts. This poses the interesting question “Could impedance changes be used to monitor movement and, consequently, be related to muscle function or activity?” This project investigated the utility of impedance change as a monitoring technique for physiological processes that involve movement such as muscular contraction, the calf muscle pump, and swallowing. The impedance of leg muscle segments during locomotion, whilst riding a stationary exercise cycle, was measured at discrete frequencies and by bioimpedance spectroscopy to monitor muscle function or activity. Impedance traces were compared to information obtained by electromyography (EMG). Impedance, at a discrete frequency, was able to measure the cadence of cycling and its magnitude was related to the position of the pedal during the pedal cycle. When the cycling action was measured by bioimpedance spectroscopy, R0 and Zc showed a statistically significant difference, (p<0.05), between all angles of the pedal crank cycle while R∞ showed a statistically significant difference between angles in the lower hemisphere of the pedal crank cycle. The cyclical changes in impedance during cycling may be attributed to changes in shape and volume of the muscle during contraction as well as a volume change due to blood and lymph being pumped from the limb by the action of the calf muscle pump. Based on procedures used in the cycling studies, an impedance-based method for the measurement of calf muscle pump function during an exercise protocol, originally designed for use with air plethysmography, was developed. It was shown that impedance measured at 5 kHz provides a simple, non-invasive method for the measurement of the ejection fraction and ejection volume of the calf muscle pump as well as other haemodynamic variables. The impedance-based method was less technically challenging than accepted volumetric methods, such as air plethysmography and strain gauge plethysmography, and non-invasive c.f. ambulatory venous pressure, enabling it to be used repeatedly. Muscle function and activity is not confined to the legs so impedance changes in the arm and forearm during exercise were measured. Impedance measurements, at discrete frequencies and using bioimpedance spectroscopy, of the forearm during contractions of the hand were able to distinguish the difference between a ramp and a pulse contraction. When the impedance of the arm and forearm were plotted against the angle of the forearm to the horizontal during a bicep curl, there was an hysteresis effect. Impedance traces of a bicep curl were compared to an EMG trace of the same action. The larynx is a hollow muscular organ situated in the front of the neck above the trachea consisting of a framework of cartilages bound together by muscles and ligaments. The two major functions of the larynx are deglutition and phonation. Dysphagia, which is becoming more prevalent as the population ages, is defined as difficulty in swallowing thin liquids such as water or juices which splash into the trachea because the patient is unable to control the thin liquid bolus. Aspiration pneumonia and dehydration can be prevented by using thickened liquids which allow patients to achieve a safer swallowing response, but it is difficult to assess this response without interfering with the swallowing process. Impedance pharynography (IPG) is a technique using BIA to monitor an impedance waveform of the swallowing process that presents no radiation hazard to the patient, is non-invasive and does not require specialist trained personnel to operate it. Resistance changes across the neck were measured while subjects swallowed solutions of different viscosities. The resistance changes were distinctive and reproducible for each of the solutions of different viscosities which were swallowed. Measuring the function of the larynx by this method could be useful in the diagnosis and treatment of dysphagia. In conclusion, the studies described in this thesis demonstrate the potential usefulness of the measurement of change in impedance as a measure of muscle activity. Impedance-based methods can measure volume changes associated with changes in cross-sectional area of the muscles involved in contraction as well as compartmental fluid changes caused by the force of the contraction on the surrounding tissues including the vasculature. In particular, measuring the ejection fraction and other haemodynamic variables of the calf muscle pump by impedance has the potential to become the method of choice in the future because it is easy to use, inexpensive, non-invasive, safe, and hygenic. Measuring resistance changes across the neck during swallowing yields distinctive waveforms with features corresponding to the physiological phases of the swallowing process as well as identifying distinctive swallowing patterns associated with the different viscosities of liquids swallowed. Function of the larynx and the associated diseases of the larynx will potentially be easier to diagnose and treat with a safe, non-invasive, inexpensive, portable bed-side method of assessment such as BIA.

Thesis (MSc (Radiography))--Cape Peninsula University of Technology, 2017. / Background: Metabolic syndrome (MetS) is a clustering of cardiovascular disease (CVD) risk factors which include abdominal obesity, hyperglycaemia, hyper-triglyceridaemia, low HDL-cholesterol and hypertension. This cluster of metabolic deviations is believed to be the primary driver of the double global epidemic of diabetes (DM) and CVD, conditions which account for much of the social and economic global burden of disease. Similar to the global trend, a high prevalence of MetS (62%) and type 2 Diabetes Mellitus (T2DM) (28.2%) has been reported for the South African mixed ancestry population, with CVD risk significantly higher in subjects with DM. The increase in MetS prevalence is driven by the obesity epidemic and anthropometric cut-off values to define MetS for this particular component of the disease has been reported to differ widely between different populations and ethnicities. Currently the waist circumference (WC) cut-off value for MetS diagnosis needs to be determined and validated per ethnic group as opposed to the previously used European derived cut-off values (Alberti et al., 2006; 2009). Validation of the WC cut-off value needs to be against one of the so called gold standards of central obesity measurement, such as Computer Tomography (CT). This technique can measure subcutaneous fat (SAT) and visceral fat (VAT) individually, which is important because VAT has been reported to be associated with MetS and CVD. The current study forms part of a large research group, investigating the prevalence and risk factors for MetS and T2DM in the South African mixed ancestry population.

The hippocampus is known to play a critical role in episodic memory function. Understanding the relation between electrophysiological activity in a rat hippocampus and rat behavior may be helpful in studying pathological diseases that corrupt electrical signaling in the hippocampus, such as Parkinson’s and Alzheimer’s. Additionally, having a method to interpret rat behaviors from neural activity may help in understanding the dynamics of rat neural activity that are associated with certain identified behaviors. In this thesis, neural networks are used as a black-box model to map electrophysiological data, representative of an ensemble of neurons in the hippocampus, to a T-maze, wheel running or open exploration behavior. The velocity and spatial coordinates of the identified behavior are then predicted using the same neurological input data that was used for behavior identification. Results show that a nonlinear autoregressive process with exogenous inputs (NARX) neural network can partially identify between different behaviors and can generally determine the velocity and spatial position attributes of the identified behavior inside and outside of the trained interval