Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder associated with increased daytime sleepiness and cardiovascular risk. Continuous positive airway pressure (CPAP), requiring a pressure-generating device connected via tubing to a mask during sleep, is an effective treatment. However, patients’ adherence to CPAP is often suboptimal. Behavioral interventions are effective in improving adherence to CPAP. We aimed to provide proof of principle for the operation of a low-cost, self-standing, internet-based system to measure and promote adherence to CPAP. The system is composed of triaxial acceleration sensors attached to the CPAP mask and to the wrist, able to record CPAP usage information, and a mobile app that collects such information and, thorough a chatbot, feeds back to the patient to improve adherence to treatment. The mask subsystem identifies time periods when the mask is put on based on relatively high values of the ratio between acceleration spectral power at frequencies <0.35
Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing and its prevalence in the general population ranges from 6–17% up to 49% in aged subjects [3, 11]. OSA is characterized by repetitive collapse of the pharyngeal airway during sleep [17]. The cause of OSA is thought to be multiple morphological and functional alterations, whose relative contributions may vary between patients. These alterations may include anatomical factors decreasing the upper airway caliber, reduced activation of upper airway dilator muscles, increased chemoreceptor drive required to recruit the pharyngeal muscles, increased loop gain of the chemoreflex control of breathing, and increased respiratory arousal threshold [17]. Furthermore, OSA increases nocturnal blood pressure due to repetitive cycles of airway obstruction and has been associated with an increased risk of cardiovascular events such as stroke, unstable angina, heart failure, and myocardial infarction [5, 12].
