Wireless body-area network for detection of sleep disorders

Abstract

Sleep disorders are presently detected using multi-sensor wired system. The Polysomnography (PSG) system, a comprehensive system for recording physiological signals during sleep, monitors the body functions during sleep. Measurements include EEG, EOG, muscle activity or skeletal muscle activation (EMG), heart rhythm (ECG) and breathing functions such as respiratory airflow and respiratory effort. The test is conducted in sleep laboratories or in the patient's home using wired sensors that affect the quality of sleep and thereby affect the quality of the test. A system that is intended to free the patient from the cumbersome cables was developed: a distributed wireless system with 8 channels of physiological sleep measurement signals. The signals at each body area are amplified, filtered, sampled and partially processed locally at the measurement site using TI MSP430 processors. Each group of adjacent sensors is connected to a local processor and the data is transmitted to a central switchboard unit using SimpliciTI technology. The center unit further arranges the data and forwards it to a Bluetooth transceiver (EZ430-RF2560). The Bluetooth transceiver is A Universal Asynchronous Receiver/Transmitter, UART. We use the UART to communicate between two peripheral device serial ports. The Bluetooth transceiver transmits the data to the end-device: a personal computer or a tablet. Data is presented on the end-device in real time and is analyzed to validate quality of measurement according to known signal statistics. At the end of the measurement session, the data is further analyzed to detect sleep stages and respiration abnormalities This system will allow measurements of respiratory effort that will be compared with actual air-flow and arterial blood oxygen saturation. The long term goal is to develop a minimal set of physiological measurements that will reliably assess sleep apnea.