Showing papers presented at "IEEE International Symposium on Medical Measurements and Applications in 2011"

Feature extraction for the differentiation of dry and wet cough sounds

Abstract: Differentiating dry and wet cough is an important factor in respiratory disease. The main objective of this paper is to analyze cough sounds and extract features that can be used in differentiation of dry and wet cough sounds. This paper proposes two features to achieve this goal. The first feature is the number of peaks of the energy envelope of the cough signal. The second feature is the power ratio of two frequency bands of the second phase of the cough signal. A set of eight highly dry and eight highly wet cough sound recordings were used. Using these two features, a clear separation was observed among the dry and wet cough sound recordings.

Enabling telecare assessment with pervasive sensing and Android OS smartphone

Abstract: Measurements of vital signs and behavioral patterns can be translated into accurate predictors of health risk, even at an early stage, and can be combined with alarm-triggering systems in order to initiate the appropriate actions. The paper presents the design and implementation of a mobile TeleCare system based on a smart wrist-worn device with a non-obtrusive sensing module for cardiac, respiratory and motor activity, a microcontroller platform for primary processing of the data from the sensors and wireless communication using Bluetooth protocol. Advanced data processing, data management, human computing interfacing and data communication are implemented using a smartphone running Android operating system (OS). A Web based health TeleCare information system was implemented being characterized by the following functionalities: data synchronization with the smartphone, advanced data processing and data presentation assuring a comprehensive data analysis and evidence based health management as well as for remote assistance of the patients by doctors and nurses. Experimental results associated with vital signs sensing and the software implementation are included in the paper.

Measurement of respiration rate in preterm infants by laser Doppler vibrometry

Abstract: The continuous monitoring of patients recovered in intensive care units is a mandatory tasks for clinicians in order to check conditions and effects of therapies. Among the many signals and quantities observable, the ones related to the heart and particularly the lung's activity are of primary interest. Today the majority of the measurement methods used for the assessment of the respiration rate are based on invasive methods (spriometry) which are often included into mechanical ventilator to which the patients, in need of assisted breathing, are attached. In this paper an optical, non-contact measurement method for monitoring of the respiration rate in pre-term infants is reported. It is based on the assessment of abdominal wall movements detected by a laser Doppler vibrometer and can be operated at a distance from the patient and outside the incubator. A total of 9 preterm patients have been monitored; respiration rates measured by a reference instrument (BabyLog 8000 Draeger plus) and the proposed non-contact method have been measured for a period of time of 60s. Data have been compared using the Bland-Altman analysis and results demonstrate an optimal correlation (R=0.97) among data and an uncertainty of the proposed method of ± 0.13s (K=2).

A novel approach to non-invasive blood glucose measurement based on RF transmission

Abstract: A new approach to non-invasive blood parameter measuring is presented, which consists of two matched antennas for transmission based two port measurements. The current situation of patients suffering from diabetes mellitus and their need for novel blood sugar level measuring techniques is presented. Dielectric properties of body tissues are reviewed and their influence on transmission properties are estimated for plane wave propagation. A covered patch antenna and substrate integrated waveguide slot antenna has been designed, measured and compromised for glucose-concentration measurements. Further, several test locations are discussed with respect to an accurate measurement. The introduced antennas were optimized and fabricated with respect to the dielectric and mounting properties of human tissues.

ECG-derived respiratory signal using Empirical Mode Decomposition

Abstract: The joint study of respiratory and cardiac activity suggests indirect methods to derive the respiratory signal by electrocardiogram (ECG) processing. Potential advantages of such methods are low cost, high convenience, and continuous noninvasive respiratory monitoring. Recent works show that the respiratory signal can be accurately evaluated by single-channel ECG processing. The aim of this paper is to introduce a new method based on the Empirical Mode Decomposition (EMD) for the respiratory signal evaluation. A comparison versus popular algorithms for the respiratory signal extraction is also shown. Preliminary results confirm that EMD algorithm provides better performances, with respect to others, especially in the case of respiratory waveform reconstruction.

A wearable device for recording of biopotentials and body movements

Abstract: Long term recording of biomedical signals such as ECG, EMG, respiration and other information (e.g. body motion) can improve diagnosis and potentially monitor the evolution of many widespread diseases. However, long term monitoring requires specific solutions, portable and wearable equipment that should be particularly comfortable for patients. The key-issues of portable biomedical instrumentation are: power consumption, long-term sensor stability, comfortable wearing and wireless connectivity. In this scenario, it would be valuable to realize prototypes using available technologies to assess long-term personal monitoring and foster new ways to provide healthcare services. The aim of this work is to discuss the advantages and the drawbacks in long term monitoring of biopotentials and body movements using textile electrodes embedded in clothes. The textile electrodes were embedded into garments; tiny shirt and short were used to acquire electrocardiographic and electromyographic signals. The garment was equipped with low power electronics for signal acquisition and data wireless transmission via Bluetooth. A small, battery powered, biopotential amplifier and three-axes acceleration body monitor was realized. Patient monitor incorporates a microcontroller, analog-to-digital signal conversion at programmable sampling frequencies. The system was able to acquire and to transmit real-time signals, within 10 m range, to any Bluetooth device (including PDA or cellular phone). The electronics were embedded in the shirt resulting comfortable to wear for patients. Small size MEMS 3-axes accelerometers were also integrated.

System for monitoring and fall detection of patients using mobile 3-axis accelerometers sensors

Abstract: This paper describes system for monitoring and fall detection of patients using triaxial accelerometer together with ZigBee transceiver to detect fall of patients. The system is composed of data acquisition, fall detection and database for analysis. Triaxial accelerometer is used for human position traking and fall detection. The system is capable of monitoring patients in real time and on the basis of results another important parameters of patient can be deducted: the quality of therapy, the time spent on different activities, the joint movement, etc. The system, including calibration of accelerometers and measurement is explained in detail.

A new tool to support diagnosis of neurological disorders by means of facial expressions

Abstract: Recognizing facial emotions is an important aspect of interpersonal communication that may be impaired in various neurological disorders: Asperger's syndrome, Autism, Schizoid Personality, Parkinsonism, Urbach-Wiethe, Amyotrophic Lateral Sclerosis, Bipolar Disorder, Depression, Alzheimer's desease. Although it is not possible to define unique emotions, we can say that are mental states, physiological and psychophysiological changes associated with internal or external stimuli, both natural and learned. This paper highlights certain requirements that the specification approach would need to meet if the production of such tools were to be achievable. In particular, we present an innovative and still experimental tool to support diagnosis of neurological disorders by means of facial-expressions-monitoring. At the same time, we propose a new study to measure several impairments of patients recognizing emotions ability, and to improve the reliability of using them in computer aided diagnosis strategies.

Magnetoelectric sensors for biomagnetic measurements

Abstract: Magnetoelectric sensors are assumed to be capable of biomagnetic measurements like magnetoencephalography (MEG) and magnetocardiography (MCG). In this paper a thin film sensor with a ME coefficient of α ME = 450 V/cmOe at a resonance frequency of f res = 678.5 Hz is investigated. Measurements show that this sensor reaches a noise level of 7.5 pT/√Hz at resonance and that field strengths in the picotesla range can be detected, which is well in the range of biomagnetic signals.

Analysis of absence seizure EEG via Permutation Entropy spatio-temporal clustering

Abstract: The genesis of epileptic seizures is nowadays still mostly unknown. The hypothesis that most of scientist share is that an abnormal synchronization of different groups of neurons seems to trigger a recruitment mechanism that leads the brain to the seizure in order to reset this abnormal condition. If this is the case, a gradual transformation of the characteristics of the EEG can be hypothesized. It is therefore necessary to find a parameter that is able to measure the synchronization level in the EEG and, since the spatial dimension has to be taken into account if we aim to find out how the different areas in the brain recruit each other to develop the seizure, a spatio-temporal analysis of this parameter has to be carried out. In the present paper, a spatio-temporal analysis of EEG synchronization in 24 patients affected by absence seizure is proposed and the results are hereby reported and compared to the results obtained with a group of 40 healthy subjects. The spatio-temporal analysis is based on Permutation Entropy (PE). We found out that, ever since the interictal stages, fronto-temporal areas appear constantly associated to PE levels that are higher compared to the rest of the brain, whereas the parietal/occipital areas appear associated to low-PE. The brain of healthy subjects seems to behave in a different way because we could not see a recurrent behaviour of PE topography.

Non contact monitoring of the respiration activity by electromagnetic sensing.

Abstract: The aim of this paper is to present a novel measurement method for the detection of the respiratory activity (respiration rate and respiration period) based on the use of a continuous wave (6 GHz) microwave radar reflectometry technique. The paper aims, in particular, to explore the effect on the signal quality of distance D between the sensing apparatus and the patient. The measurement method proposed is based on the measurement of the phase variation of the reflection coefficient (S 11 ) signal measured by a vectorial network analyzer connected to a double ridge horn antenna. The S 11 signal has been compared with the synchronous acquisition made by means of a laser Doppler vibrometer (LDVi), measuring the thorax oscillations caused by the respiratory activity. Both signals have been filtered in order to eliminate the effect of high frequency disturbances (heartbeat) and noise. Results show an high correlation between respiration peaks measured with the proposed system and with LDVi; a reduction of the amplitude of the S 11 signal phase (as well as the SNR) is reported in correspondence to an increasing of the distance D (−0.11 dB/cm). Tests have been repeated for standing as well as for sitting condition of the subject confirming a better signal quality for the later. Despite the fact that S 11 phase variation and SNR are reduced by the distance D, in our experiments, it is still possible to correctly measure the respiration period up to 2.5 m. Data measured show that the reflectometeric approach can be used to monitor at distance with sufficient high SNR (18 dB at 2.5 m) the respiration activity of a subject without the need of a direct contact with the subject skin by means of electrods of sensing belts.

Multi-parameters wireless shirt for physiological monitoring

Abstract: The ability to monitor the health status of elderly patients or patients undergoing home therapy allows significant advantages in terms of cost and convenience of the subject. However, these non-clinical applications of biomedical signals acquisition require different monitoring devices having, between the other characteristics, reduced size, low power and environment compatibility. The research activity concerns the development of a new wearable device that can monitor the main physiological parameters of a person in a non-invasive manner. All sensors have contactless characteristics that permit to avoid the direct contact with the skin. This system is a useful solution for monitoring the health condition of patients at home. The wearable monitoring system consists of two subsystems: first, a wearable data acquisition hardware, in which the sensors are integrated for the acquisition of biomedical parameters, and secondly, a remote monitoring station located separately and connected to the Internet for telemedicine applications. The physiological parameters that are monitored are electrocardiogram (ECG), heart rate (HR), derived from ECG signals through the determination of RR intervals, respiratory rate, and three-axis motion (acceleration and position) of the subject measured using an accelerometer. All sensors are designed using contactless measurement techniques, thus avoiding the use of gel for the conduction of the signal and possible skin irritation due to contact. The electrodes for measuring ECG signal are capacitive, while the measure of respiration is obtained by plethysmography, which does not require direct contact with skin. In order to design and construct the signal acquisition circuits in an efficient and simple manner, modular design concept is adopted in this research. The flexible signal conditioning modules are designed and assembled together. The human parameters can be recorded and analyzed continuously during work activities at home. The correct evaluation of these parameters allows the medical staff to assess to the state of health, to know accidental injury or other danger occurred in patients at home.

Efficient implementation and evaluation of wavelet packet for 3D medical image segmentation

Abstract: 3D volume segmentation aims at partitioning the voxels into 3D objects (sub-volumes) which represent meaningful physical entities. Multi-resolution analysis (MRA) allows for the preservation of an image according to certain levels of resolution or blurring. The quality of this approach makes it useful in image compression, de-noising, and classification or segmentation. This paper focuses on the implementation of a medical volume segmentation technique using different wavelet decompositions such as discrete wavelet transform (DWT) and discrete wavelet packet transform (WP). A comparison study has been carried out to evaluate both decompositions using different performance metrics such as Euclidean distance (ED) and dice similarity coefficients (DSC) which reveal that WP approaches can accurately detect the perform the details coefficients in both phantom and real data.

Context aware serious games framework for sport and health

Abstract: Serious Games for Sport and Health are a promising chance to help people to improve their health. In this paper, we address the challenges of adding context awareness to Serious Games for Sport and Health. We propose a framework for social networks and web services that is specialized in capturing temporal and spatial context as well as vital parameters of a user. Our framework dynamically maps necessary e-Health services such as exergames. In this way, we assist a user to find the most appropriate health services according to his/her needs at anytime and anywhere. We present our initial proof of concept implementation of the framework, which includes new sensor based Serious Games for Sport and Health as well as our test results.

Innovative textile electrodes for muscles electrostimulation

Abstract: The textile electrodes are used to muscles electrostimulation during the therapy. The textile electrodes are new product which can replace the traditional metal or graphite electrodes. They are elastic and good fitted to body shape (legs or arms). The presented solution decreased contact resistance between textile electrodes and human skin. The elaborated electrodes are located in textile band, ortez or socks in electrostimulation places. This kind of product we called textronic. In the article the method of textile electrodes production is described. To the manufactured electrodes new electroconductive textile materials are used. They consist of silver particles. New technologies, like plasma treatment, impregnate method or printing technology, was used to the modification of textile layers. In the articles authors also described the method of surface resistance distribution measurement, which is quality evaluation criterion of innovative textile materials to electrodes construction.

Maximal ratio combining for respiratory effort extraction from pressure sensor arrays

Abstract: Respiratory effort signals may be measured using pressure sensors placed below a mattress. When few of the sensors include the respiratory effort signal or the signal power is low, output respiratory effort signal quality is low. This paper examines current signal combining methods used in pressure sensor array breathing estimation and proposes a maximal ratio combining method to produce the best estimate in these conditions. Data was collected from two participants and the effects of low signal power and low signal availability were simulated by corrupting the recordings. The results show that the proposed method offers 2.5 dB higher signal to noise ratio in the presence of substantial noise and good correlation (> 0.92) to gold standard respiration bands.

Mirror therapy with an exoskeleton upper-limb robot based on IMU measurement system

Abstract: This paper develops a novel system which includes an exoskeleton upper-limb robot and an inertia motion unit (IMU) measurement system based on mirror therapy concepts with assistive robotics. By integrating the IMU measurement system and the exoskeleton robot, we can execute measurement and control over larger range of motion (ROM) and also improve the safety and user-friendliness of the system. In this paper, two methods using IMU to measure various orientations of parts of the master-side's upper-limb have been proposed, and then the posture trajectory of the disabled part of the slave's side will be automatically generated. Conceivably, these two methods can create more complex trajectories than conventional approaches which design specific type of trajectories. Besides that, the accuracy and safety of orientation measurement are very important issues when robot-assisted exercises are conducted. To achieve this objective, we particularly develop a point-to-point control system consisting of two different types of position measurement components along with a PID controller, and both monitor each other to make the system more robust and to prevent the single point of failure problem while the system is working.

The effect of mental stress on psychophysiological parameters

Abstract: A set-up for evaluating psychophysiological parameters during mental stress tests is described. The set-up was composed of a continuous non-invasive blood pressure monitor, skin conductance and skin temperature measurement devices and body heat-flux meter. Twelve healthy volunteers were tested using two different mental stress tests (Stroop colour-word conflict test and mathematical subtraction test). For comparison, also a physical test was employed. The results indicated that along the increase in heart rate and skin conductance, also systolic and diastolic blood pressure levels increased during all tests. Mental stress tests had weaker effect on psychophysiological parameters of the subjects as compared to physical activity. The results indicate that continuous blood pressure monitoring is a reliable physiological measurement, well correlated with mental and physical stress tests. The results also demonstrated the body heat-flux measurement could be an additional or supplemental measuring tool instead of skin temperature.

New scenarios in human trunk posture measurements for clinical applications

Abstract: It is well established how maintaining a correct body posture is absolutely fundamental to prevent skeleton and muscular pathologies. For instance the trunk's postures assumed in a typical working day for who spends many hours in front of a pc-screen, or the typical motion behaviour in the classroom routine for the pupils, can even lead to some body handicaps. Accordingly, it appears obvious how the exact evaluation of assumed postures during the possible daily activities is the starting point for the adoption of related prevention expedient or the application of subsequent medical treatments. On the basis of our experience, this paper deals with the common adopted systems for measuring human postures, especially related to the torso, suggesting a complete classification scheme, and imaging new possible future scenarios for clinical applications.

Multi-resolution analysis using curvelet and wavelet transforms for medical imaging

Abstract: Curvelet transform is a new extension of wavelet transform which aims to deal with interesting phenomena occurring along curves. Curvelet transform is particularly a challenging task to classify human organs in CT scans using gray-level information. An efficient implementation of curvelet transform for medical image segmentation and denoising has been presented in this paper. A comparison study has been carried out in this paper between different transforms which reveals that curvelet transform exhibits optimal representation of the region of interest (ROI) with better accuracy and less noise.

Electronic measurements in rehabilitation

Abstract: The paper presents a review of the scientific literature in the field of measurements aimed at supporting the different phases of the rehabilitation. Several papers have been analyzed and classified on the basis of the rehabilitation phase and the type of proposal.

Kinematics patterns of upper arm reaching movement in robot-mediated therapy

Abstract: Robot-mediated therapy has been a very dynamic area of research in recent years. It promises improvement in sensorimotor as well as cognitive processes and has several advantages, among them the most important is perhaps the possibility to quantify the performances of the rehabilitation task proposed to the patient. Robotics devices are in fact capable to guide or perturb movements of a patient's limb and can record mechanical quantities such as position, velocity and forces applied. The kinematics quantitative assessments allow to estimate patient's progress, whilst the clinical traditional scales permit only quantitative evaluations. Different systems for robot-aided neurorehabilitation are currently available for upper limb rehabilitation. However, none study indicated a standardized quantitative kinetic evaluation of robot assisted upper arm free reaching three-dimensional movements. In this paper a quantitative kinematic assessment of robot assisted upper arm free reaching movements is proposed. Advised indexes can be useful for describing normal patterns and for implementing and testing rehabilitative strategies patients oriented.

The image recognition of brain-stem ultrasound images with using a neural network based on PCA

Abstract: This paper describes how to recognize substantia nigra (SN) area in ultrasound brain-stem images. The main goal is the classification of ROI SN in midbrain. The classification of images is useful to detection Parkinson's disease (PD), defects in SN. Work is based on image processing and is realized with the help of artificial neural networks and solve is realized with MATLAB, with Image Processing and Neural Network Toolboxes.

Preliminary evaluation of a fiber-optic sensor for flow measurements in pulmonary ventilators

Abstract: A novel optical fiber air flow sensor was developed for monitoring flow rates supplied by infant ventilators. The device is based on a fiber optic sensing technique and overcomes some important shortcomings of biomedical applications, such as electromagnetic interference and possible electrical hazard. The sensing principle is based on measuring the displacement of an emitting optical fiber cantilever by means of a photodiode linear array: the detection of the illumination pattern makes the developed system less sensitive to light intensity source variations than intensity-based sensors. A preliminary evaluation of the relationship between displacement and flow rate is theoretically and experimentally conducted, as well as a measurement range up to 3.00·10−4 m3/s (18.0 l/min) has been verified, in accordance to the flow range usual for tidal breathing of infants.

Textronic clothing to ECG measurement

Abstract: Continuous measurement of physiological parameters enable to monitoring healthy and ill state of patients or people who are exposed to health hazard what is the result of their professions. Rescuers (firefighters, chemical rescuers etc.), solders, policemen and people practicing of competitive sport include of this category. Measurement of chosen vital signs is possible using textronic clothing that includes sensors and measurement setups integrated with clothing structures. Sensors implemented in clothing ensures noninvasive measurement method, without interfering into human body. In this paper authors presented the textronic system to ECG measurement. This system consists of two parts: textile and electronic modules. Textile module composed of shirt with integrated textile measurement ECG electrodes connected with electronic measurement system. Measurement electrodes have a composite, textile structure and they were made from electroconductive textile materials. To construction used silver woven fabric. The woven fabric was prepared by Soliani SML company from Italy. Measurement system for ECG monitoring used three electrodes. These electrodes were connected to low offset voltage, very precise instrumentation amplifier. Signal from amplifier were filtered by computer software. The ECG signal was analyzed after filtering. During research properties of textiles ECG electrodes was compared with traditional ECG medical electrodes

Detection of bouncing during sit-to-stand transfers with sequential pressure images

Abstract: As adults age or suffer from physical ailments, their level of functional strength and mobility can decrease over time. One indicator of a loss of muscle strength is the occurrence of bouncing during the sit-to-stand sequence while exiting a bed. This paper presents two algorithms designed for the detection of bouncing from pressure images and tests them on segments of healthy, simulated bouncing and post-stroke patients. The first algorithm relies on pressure measurements from the regions of contact by the hips and hands. This algorithm is found to be most accurate when the hands are both placed on the bed at a distance from the hips but decreases in accuracy when they are either placed too close, on top of the thighs or not used at all. To compensate for this, the second algorithm considers the full image as one region and measures the centroid along with the total pressure over time. This algorithm is successful at bounce detection regardless of the region definition, but can lose accuracy when the patient pushes off the bed with little forward lean. The intelligent fusion of these two algorithms within a mobility monitoring system can provide the detection of bouncing in a wide range of occupants within the smart home environment.

Bilateral asymmetry identification for the early detection of breast cancer

Abstract: Breast cancer is the second most common cancer overall and the leading cause of cancer deaths in women. Mammography is, at present, the only viable method for detecting most of tumors early enough for effective treatment. The secret of setting up the accurate diagnosis is to detect and understand the most subtle signs of breast lesions. Analysis of asymmetry between the left and right mammograms can provide clues about the presence of early signs of tumors. In this work we present an automated procedure for bilateral asymmetry detection composed of the following steps: (1) mammography density analysis and fibro-glandular disc detection through adaptive clustering techniques, (2) analysis and implementation of bilateral asymmetries detection algorithms based on Gabor filters analysis, (3) use of a linear Bayes classifier with the leave-one-out method to asses the asymmetry degree of the two breasts, (4) metrological evaluation of the whole system through random and systematic measurement uncertainty contributions modeling.

Laser Doppler vibrometry for in vivo assessment of arterial stiffness

Abstract: It has been shown that in cardiovascular risk management, stiffness of large arteries has a very good predictive value for cardiovascular disease and overall mortality. This parameter can be estimated from the pulse wave velocity (PWV) measured between the common carotid artery (CCA) (neck) and femoral (groin) artery. However, current methods to determine arterial PWV suffer from several shortcomings. In this work, we propose a novel, non-contact laser Doppler vibrometry (LDV) technique, for evaluating carotid PWV, directly from CCA. This approach was extensively validated in vitro, and here it is tested for the first time on a small group of young healthy volunteers. Our preliminary results demonstrate that laser-based non-contact measurement of PWV is feasible, as measured PWV values are consistent with the literature. With possible clinical applications in mind, the non-contact character of the method combined with the possibility to measure carotid PWV, promises important advantages over existing methods. Moreover, measurements are straightforward and do not require intensive training.

Development of a remote system for real-time control of intravenous drip infusions

Abstract: This article explores the use of a microwave reflectometry-based system for the automatic control and real-time monitoring of the flow and of the liquid level in intravenous medical infusions. In medical and hospital contexts other kind of devices, mainly based on the optical detection and counting of the infusion drops, are used. Nevertheless, the proposed system is aimed at circumventing some typical drawbacks deriving from the optical sensing, thus allowing an efficient alternative solution for automatically monitoring the instantaneous flow of intravenous medical solutions. To this purpose, the proposed system combines microwave time domain reflectometry (TDR) measurements with a non-invasive sensing element (i.e.: strip electrodes directly attached to the external surface of the infusion bottle). Experimental results confirm that, by using low-cost portable TDR devices, the solution flow process can be accurately controlled. Therefore the proposed method can be successfully adopted as a promising control tool for in-hospital patient management as well as for telemedicine programs.

Measuring heart rate, breathing rate and skin conductance during exercise

Abstract: Sensor miniaturization and advances in low power communication protocols have helped enable continuous monitoring of physiological signals. Commercial products exist today which are wearable, in a form of a chest belt or a wrist strap, and can continuously stream or log bio-signals such as heart rate, as well as motion signals. Such devices could be of importance not only to a health-conscious consumer, but also in the healthcare system, for monitoring of patients whose prescribed treatment includes some form of physical activity. This paper proposes a new framework for monitoring compliance and impact of an exercise regimen. While previous related work typically uses an accelerometer based approach, our method gives a more complete picture of impact of exercise on the subject by adding bio-signals such as heart rate, breathing rate and skin conductivity and correlating them with motion signals. Such framework can be used to assess progress over time for different types of exercise regimens.