Design of a wireless polysomnography device

Respiratory problems such as breathing difficulties during sleep, sleep apnea and snoring are life-threatening sleep disorders that adversely affect sleep quality. Diagnosis of sleep disorders is also vital. Polysomnography, which is accepted as the gold standard diagnostic method for sleep related respiratory disorders, can be defined as the real-time recording of the nervous system, cardiorespiratory system and some sleep-related physical and physiological parameters such as body position and body temperature during the falling asleep process, during and after sleep using inoperative electrophysiological monitoring methods. The data collected during the test are examined by the specialist physician and if there is a sleep disorder, the diagnosis is made after the examination of test results. Polysomnography tests are quite costly, and sleep centers have a limited number of rooms, polisomnographies and sleep technicians for the test. Therefore, devices that allow sleep tests to be performed at home have been produced to reduce test costs and serve more patients. These devices are generally known as Home Sleep Apnea Test (HSAT) kit. HSAT kits monitor and record vital signals such as oxygen concentration in the blood (SpO2), body position, and respiratory activity. In this study, we aimed to make sleep tests at home for patients vii with sleep problems without the need for a sleep technician and to monitor the patient's vital signals instantly; An IoT-based, battery powered, wearable and compact wireless polysomnography system has been designed. The system, has calculation power and wireless communication capabilit of Espressif ESP32 SoC, can collect EEG, ECG, 3- axis inertial measurement unit, respiratory effort, nasal pressure sensor signals 200 times per second; calculate SpO2 with the help of Pulse Oximeter and able to send all collected data over the wireless network. This PSG device is a Type II comprehensive portable test device according to the American Academy of Sleep Medicine Guidelines. The SCOPER (Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory) score obtained is S2 C1 O1 P2 E2 R2. All data collected from the patient are transmitted to a target via the 2.4GHz Wi-Fi network using TCP/IP protocol. A Python application has been developed to monitor and record the collected data. In tests conducted with network monitoring applications, it was observed that 200 packets were transmitted per second without packet loss.