1,720,982 research outputs found
Cardiovascular disease and sleep apnoea: A wearable device for PPG acquisition and research aims
No full textA Wearable Device for PPG Acquisition and Continuous Detection of Sleep Apnea Episodes
No full textObstructive Sleep Apnea Syndrome (OSAS) is a common sleep related disorder that causes the cessation of breathing during sleep. The Gold Standard for diagnosing sleep apnea (SA) is overnight polysomnography (PSG), a test during which various physiological parameters are monitored. However, PSG is an expensive and time-consuming procedure, since it requires dedicated personnel and labs. In the past years, various techniques have been proposed for home-diagnosis of SA, like monitoring ECG and oxygen saturation, air flow, thoracic movements, respiratory sounds, and others. The aim of this work is to presents a microcontroller-based, Bluetooth enabled, wearable device for real-time acquisition of photoplethysmographic (PPG) signal and a MATLAB-based digital framework for PPG processing. The wearable device is embedded in a comfortable cotton headband, making it easy to wear and suitable for different measurement scenarios, such as clinical environments, during sport activities, during sleep, and so on. To measure the PPG signal we chose the NellcorTM Max-Fast Forehead SpO2 reflectance sensor. Thanks to the wireless communication link to a PC, the wearable device can be used both in clinical scenarios and at home, in telemedicine systems. At the same time, the digital signal processing framework allows new algorithms research on automatic analysis of PPG signals for detection and diagnosis of sleep apnea
A PCB system implementation for neural signals recording and PNS stimulation
No full textA bidirectional interface for neural recording and stimulation is proposed. The recording circuitry eliminates the outband interferences thanks to a high selective band pass filter in the 1:1kHz-2kHz band, providing a gain of 24dB. Further amplification is obtained by means of a programmable gain amplifier that can bring the gain to 44dB. The signal is then digitalized with a 16 bit ADC and sent to a microcontroller. In order to minimize the input referred noise, the whole signal acquisition chain has been designed with a Fully Differential approach, by this way an IRN of 364nV has been achieved. Stimulation signals are biphasic current pulses with programmable duration, frequency and amplitude. These patterns are generated by a DAC followed by a Voltage to Current converter. The programmability of the pulse parameters is guaranteed by the microcontroller: the current amplitude can range from 5μA to 20μA, the pulse duration varies from 50μs to 150μs while the frequency can cover from 10Hz to 400Hz. The system has been implemented in a PCB and successfully tested with a pre-recorded neural signal extracted by the peripheral nervous system of a rabbit with a tfLIFE electrode
KeepInTouch: A telehealth system to improve the follow-up of chronic patients
No full textWith the progressive ageing of the western people, the number of chronic patients requiring a continuous follow-up by the physicians increases. Even though telehealth solution can be potentially effective in such a scenario, both the age factor and often the cost of the systems hamper the diffusion of telehealth systems. KeepInTouch is a low cost system for telehomecare conceived for the daily off-line monitoring of diabetic and cardiac patients. It exploits a mixed approach offering a simple TV-based front-end from the patient side, and a web-based one from the physician side. The web-based approach enables the authorized medical professionals to access the patient data from the web, exchanging useful information and providing textual feedback to the patient, all within the system interface. The patient's front-end is based on the Digital Video Broadcasting Terrestrial (DVB-T) technology, exploiting an acquisition unit connected to the patient's certified biomedical devices (sphygmomanometer, glucometer, body weight scale) and with the interactive DVB-T set-top box in order to provide a user-friendly interface on the TV for people not accustomed with computers. The system is going to be used for a first clinical trial in Italy
Myocardial infarction and Antiphospholipid Syndrome: A first study on finger PPG waveforms effects
No full textDesign of a Programmable Bioelectrical Impedance System for Biomedical Applications
No full textThe design of a portable,versatile and programmable bioelectrical impedance system is presented. The device uses in expensive off-the-shelf components to perform multi-frequency current injection and voltage measurements through skin electrodes. The impedance measurement system can be configured as multi-frequency bioelectrical impedance analyzer as well as acupuncture point detector, for localizing pathologically changed acupuncture points on the body. In order to improve the accuracy and the flexibility of the measurements, a programmable wide frequency band width current source has been designed. It allows to generate sinusoidal and square wave forms with a frequency up to 1 MHz and amplitude values in the range of [12 mu A(pp)-1.2mA(pp)]. The measured signals can be amplified with a programmable gain and converted with 16 bits of resolution before being transmitted to a PC through USB transmission for further processing
A Microcontrolled Constant Current Source for Wideband Bioimpedance Measurements
No full textWe describe a programmable wide frequency bandwidth current source realized using a COTS-based (Commercial Off-the-Shelf) design. It is capable of injecting sinusoidal, square or triangle current waveforms of amplitude ranging from 12μApp to 1.2mApp and frequency up to 1MHz, into the human body through a pair of electrodes. The device is controlled by a graphic user-friendly interface, which allows users to monitor data transmission and acquisition as well as to set current injection parameters. In addition to current injection, the system is meant for sensing in real time the resulting response. The measured voltage drop across tissue impedance can be amplified with a programmable gain and converted into digital values with 10 bits of resolution before being transmitted to a PC through USB transmission for further processin
A Pervasive Telemedicine System Exploiting the DVB-T Technology
No full textTelemedicine is a form of remote assistance to patients unable to easily reach the hospitals. The diffusion of such systems depends both on the availability of widespread low-cost platforms and on the ease of use. In this paper, a DVB-T based platform for telemedicine is presented. The proposed system enables to perform simple routine exams through a low-cost Base Station connected to the patient's DVB-T set-top box, using the remote control and the TV screen as I/O interfaces for the user. The uplink connection is used to send the results to a remote care center. The practice with such home-entertainment equipments allows even elderly people to easily exploit the proposed platform
KeepInTouch: applicazione della tecnologia DVB-T per il monitoraggio remoto di pazienti diabetici e cardiopatici
No full textAn electronic interface for neural recording and stimulation
No full textA portable neural activity acquisition and stimulation system by means of tfLIFE implantable electrodes has been realized. The detecting circuit provides: a selective filtering made up of a 4th order high pass Multiple Feedback filter (f-3dB = 1.1 kHz) and a 4th order low pass Multiple Feedback filter (f-3dB = 2kHz), a variable gain (24dB - 44dB) and a 16 bit analog to digital conversion. The stimulator allows to generate specific electrical signals through a digital-to-analog converter while stimulation parameters as frequency, duration and intensity are controlled by a digital microcontroller. Simulation results and first experimental results of the interface demonstrate how neural signals of a few of microvolts can be filtered, programmable amplified and digitalized without distortion
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