Luis Felipe Crespo Foix

An Accelerometer-Based Device for Sleep Apnea Screening

This paper presents a body-fixed-sensor-based approach to assess potential sleep apnea patients. A trial involving 15 patients at a sleep unit was undertaken. Vibration sounds were acquired from an accelerometer sensor fixed with a noninvasive mounting on the suprasternal notch of subjects resting in supine position. Respiratory, cardiac, and snoring components were extracted by means of digital signal processing techniques. Mainly, the following biomedical parameters used in new sleep apnea diagnosis strategies were calculated: heart rate, heart rate variability, sympathetic and parasympathetic activity, respiratory rate, snoring rate, pitch associated with snores, and airflow indirect quantification. These parameters were compared to those obtained by means of polysomnography and an accurate microphone. Results demonstrated the feasibility of implementing an accelerometry-based portable device as a simple and cost-effective solution for contributing to the screening of sleep apnea-hypopnea syndrome and other breathing disorders.

Mapping the Human Body for Vibrations using an Accelerometer

In this paper, an accelerometer is used to measure the vibration of the neck and thorax, in order to detect important signals that can be used in the diagnosis of sleep apnoea. Accelerations produced by the heart signals, the breathing movement and the snoring sounds are detected by an accelerometer attached to the skin. Mean power levels of the signal in different frequency bands are used to map the surface of the neck and thorax, where the accelerometer has been positioned in 15 different locations. A program in Matlab is used to fit this surface plot. Getting an adequate location for the accelerometer is a clear help to the diagnosis of sleep apnea.

A novel multimodal tool for telemonitoring patients with COPD

Introduction: Among factors that underlie high rates of non-participation reported in telehealth interventions are the low older users’ acceptance of information technologies and the low levels of non-compliance with therapy of chronic patients. Therefore, inclusion of potential users into design stages of assistive technologies is challenging. In this paper, the design, implementation and evaluation of a multimodal mobile application for telemonitoring chronic obstructive pulmonary disease (COPD) is presented. The goal of the study was to assess the usability and feasibility of the designed tool. Methods: An iterative user-centered design methodology was applied to implement a prototype that satisfied users’ requirements. Feasibility (compliance, COPD knowledge and satisfaction) of the application was assessed in a 6-month field trial with COPD patients. Results: A usable, effective and efficient prototype was released after the development process. A high compliance (86.1%) and an increasing in COPD knowledge were achieved in the field trial. Conclusions: The findings reveal the importance of integrating usability in the design development processes to improve adherence to routine tasks and to reduce the high rates of non-participation reported in recent evaluation studies of telehealth interventions. The presented tool can help to recognize early symptoms of deterioration and to support patients in COPD self-management.

Monitoring and Analysis of Cardio Respiratory and Snoring Signals by using an Accelerometer

In this paper we present a system based on a sensor of acceleration for acquisition and monitoring of diverse physiological signals, by extracting respiratory, cardiac and snoring components inside the main source. Digital signal processing techniques used frequently in Biomedical Engineering have been used. The acceleration produced by the cardiac signals, the respiratory movements and the vibrations generated by the snores are detected with help of an accelerometer placed on the skin of the subject in not invasive way. The presented device allows the monitoring of several biomedical parameters: heart rate (HR), heart rate variability (HRV), Sympathetic, parasympathetic and baroreflex activity, respiratory rhythms and their variations (bradypnea - tachypnea), snoring and abdominal-thoracic efforts. A simple and effective method and device [1] is provided for helping to the diagnosis of Sleep Apnea-Hypopnea Syndrome (SAHS) and other breathing disorders.