Limb’s Vibrations Exercise Monitoring with MEMS Accelerometer to Identify Influence of Cardiovascular System

Katsuzo Nishi in 1927 proposed the capillarity exercise based on limbs vibrations to compensate obstruction of blood circulation. Research was made to identify influence of vibrations to human’s physiological parameters. There were made an exercise regarding to Nishi methodology and imitation of exercise with one arm on vibration stand while monitoring physiological parameters and accelerations. Detected parameters’ changes were significantly smaller when vibrating only one hand. Future plans are to imitate exercise while vibrating all limbs and make a stand to imitate cardiovascular system to identify vibrations influence in blood flow rate

Photoplethysmogram Signal Morphology-Based Stress Assessment

Stress is a healthy natural response to a perceived or actual threat. However, when stress is persistent, it may decrease work productivity, increase the risk of diseases, and affect the quality of life. Stress is reflected in physiological variables, such as heart rate, blood pressure, and pulse wave velocity among others. A photoplethys-mogram (PPG) contains information related to pulse rate and blood pressure. This study analyses parameters derived from PPG signal morphology for mental stress assessment.A low-complexity algorithm is designed using bandpass filtered higher-order derivatives of the PPG signal for estimation of six morphological parameters: the forward pulse wave amplitude A1, the systole and diastole durations T1 and Td, the time delays of reflected waves T12 and T13 from the renal and iliac sites in the central arteries, and the pulse duration Tp. The parameters were investigated on a set of 18 healthy subjects by using a modified Trier Social Stress Test.The results show that the most sensitive PPG morphology parameters to mental stress are the amplitude of forward wave A1, the duration of diastole Td, the time delay of the reflected wave T13, and the pulse-to-pulse interval Tp

Algorithms and Results of Eye Tissues Differentiation Based on RF Ultrasound

Algorithms and software were developed for analysis of B-scan ultrasonic signals acquired from commercial diagnostic ultrasound system. The algorithms process raw ultrasonic signals in backscattered spectrum domain, which is obtained using two time-frequency methods: short-time Fourier and Hilbert-Huang transformations. The signals from selected regions of eye tissues are characterized by parameters: B-scan envelope amplitude, approximated spectral slope, approximated spectral intercept, mean instantaneous frequency, mean instantaneous bandwidth, and parameters of Nakagami distribution characterizing Hilbert-Huang transformation output. The backscattered ultrasound signal parameters characterizing intraocular and orbit tissues were processed by decision tree data mining algorithm. The pilot trial proved that applied methods are able to correctly classify signals from corpus vitreum blood, extraocular muscle, and orbit tissues. In 26 cases of ocular tissues classification, one error occurred, when tissues were classified into classes of corpus vitreum blood, extraocular muscle, and orbit tissue. In this pilot classification parameters of spectral intercept and Nakagami parameter for instantaneous frequencies distribution of the 1st intrinsic mode function were found specific for corpus vitreum blood, orbit and extraocular muscle tissues. We conclude that ultrasound data should be further collected in clinical database to establish background for decision support system for ocular tissue noninvasive differentiation

Wearable-based assessment of heart rate response to physical stressors in patients after open-heart surgery with frailty

Due to frailty, cardiac rehabilitation in older patients after open-heart surgery must be carefully tailored, thus calling for informative and convenient tools to assess the effectiveness of exercise training programs. The study investigates whether heart rate (HR) response to daily physical stressors can provide useful information when parameters are estimated using a wearable device. The study included 100 patients after open-heart surgery with frailty who were assigned to intervention and control groups. Both groups attended inpatient cardiac rehabilitation however only the patients of the intervention group performed exercises at home according to the tailored exercise training program. While performing maximal veloergometry test and submaximal tests, i.e., walking, stair-climbing, and stand up and go, HR response parameters were derived from a wearable-based electrocardiogram. All submaximal tests showed moderate to high correlation ( r = 0.59–0.72) with veloergometry for HR recovery and HR reserve parameters. While the effect of inpatient rehabilitation was only reflected by HR response to veloergometry, parameter trends over the entire exercise training program were also well followed during stair-climbing and walking. Based on study findings, HR response to walking should be considered for assessing the effectiveness of home-based exercise training programs in patients with frailty

Subjective visual vertical assessment with mobile virtual reality system

BACKGROUND AND OBJECTIVE: The subjective visual vertical (SVV) is a measure of a subject's perceived verticality, and a sensitive test of vestibular dysfunction. Despite this, and consequent upon technical and logistical limitations, SVV has not entered mainstream clinical practice. The aim of the study was to develop a mobile virtual reality based system for SVV test, evaluate the suitability of different controllers and assess the system's usability in practical settings. MATERIALS AND METHODS: In this study, we describe a novel virtual reality based system that has been developed to test SVV using integrated software and hardware, and report normative values across healthy population. Participants wore a mobile virtual reality headset in order to observe a 3D stimulus presented across separate conditions – static, dynamic and an immersive real-world (“boat in the sea”) SVV tests. The virtual reality environment was controlled by the tester using a Bluetooth connected controllers. Participants controlled the movement of a vertical arrow using either a gesture control armband or a general-purpose gamepad, to indicate perceived verticality. We wanted to compare 2 different methods for object control in the system, determine normal values and compare them with literature data, to evaluate the developed system with the help of the system usability scale questionnaire and evaluate possible virtually induced dizziness with the help of subjective visual analog scale. RESULTS: There were no statistically significant differences in SVV values during static, dynamic and virtual reality stimulus conditions, obtained using the two different controllers and the results are compared to those previously reported in the literature using alternative methodologies. The SUS scores for the system were high, with a median of 82.5 for the Myo controller and of 95.0 for the Gamepad controller, representing a statistically significant difference between the two controllers (P < 0.01). The median of virtual reality-induced dizziness for both devices was 0.7. CONCLUSIONS: The mobile virtual reality based system for implementation of subjective visual vertical test, is accurate and applicable in the clinical environment. The gamepad-based virtual object control method was preferred by the users. The tests were well tolerated with low dizziness scores in the majority of patients

Formalization of the observations of the sea level variations using XML data schemas and scalable vector graphics format

XML (Extended Markup Language) Data Schemas as the format for information exchange in graphical SVG (Scalable Vector Graphics) format is presented in the paper. SVG file format is a language for two-dimensional graphics and is based on XML. It is suggested to apply it as the advanced version of previous data exchange format TGINEX (Tide Gauge Independent Exchange Format), which contains the plain ASCII data. SVG graphics are formatted from the observations of sea level observations by the tide gauges. As an example, the formalization of data is shown on the base of the sea level observing station KLPD, which is a part of the European Sea Level Service network. XML Data Schemas, in addition, adds header’s information about the marine measurements' site, sensors and any additional necessary information. The correct header formation and the advantages of such data exchange format are analysed. Header is important for exchange between different sites from different countries as so it would be information standartization. Visual appearance of the SVG file, the source, headers and formation of the file in script are described in this paper als

Formalization of the observations of the sea level variations using XML data schemas and scalable vector graphics format

XML (Extended Markup Language) Data Schemas as the format for information exchange in graphical SVG (Scalable Vector Graphics) format is presented in the paper. SVG file format is a language for two-dimensional graphics and is based on XML. It is suggested to apply it as the advanced version of previous data exchange format TGINEX (Tide Gauge Independent Exchange Format), which contains the plain ASCII data. SVG graphics are formatted from the observations of sea level observations by the tide gauges. As an example, the formalization of data is shown on the base of the sea level observing station KLPD, which is a part of the European Sea Level Service network. XML Data Schemas, in addition, adds header’s information about the marine measurements' site, sensors and any additional necessary information. The correct header formation and the advantages of such data exchange format are analysed. Header is important for exchange between different sites from different countries as so it would be information standartization. Visual appearance of the SVG file, the source, headers and formation of the file in script are described in this paper als

Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions