A FPGA-based wearable ultrasound device for monitoring obstructive sleep apnea syndrome

• Main Authors: Chi-KaiWeng, 翁祺凱
• Other Authors: Chih-Chung Huang
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/ynhcp3

碩士 === 國立成功大學 === 生物醫學工程學系 === 104 === Obstructive sleep apnea (OSA), a breathing disorder characterized by repetitive collapse of the pharyngeal airway during sleep, can cause intermittent hypoxemia and frequent arousal. Many studies have demonstrated that the deformation of tongue base plays an important role in OSA. Currently, several medical imaging modalities have been used to record the airway changes, such as cine MRI and ultrafast CT. However, most of them are difficult to be used widely in clinical diagnosis for continuous recording the deformation of tongue in real-time, particularly during sleeping. In order to overcome these problems, a wearable ultrasonic device was developed for real-time monitor of the dynamic change of the tongue base in this study. The device includes a custom-designed 3-MHz ultrasonic array transducer, an ultrasound pulser/receiver, high speed analog-to-digital converter, and a FPGA board. The ultrasound pulse repetition frequency and pulse center frequency are controlled by the programmable FPGA board. Since this device exhibits non-invasive, real time imaging, portable, and non-ionizing radiation, it can be used to detect the airway situation during natural sleeping with various postures. This new information will help physicians to diagnose the symptoms. The anthropometric measurement was carried out for verifying the system performance. Results demonstrated that the dynamic variation of tongue base can be clearly distinguished by using this wearable system. It has the potential to be incorporated into polysomnography and to provide information about retroglossal airway behavior during natural sleep. Furthermore, it is very important in devising, applying and determining the effectiveness of tailor-made treatment modalities.