Assessments for sleep apnea often involve spending a night in a clinic hooked up to various sensors that can actually prevent a patient from sleeping properly. But according to recent research, a Fitbit-like device could serve the same purpose while a patient is sleeping at home.
The research was led by doctoral researcher Gabriele Papini at the Eindhoven University of Technology in the Netherlands. It incorporates a wrist-worn device, similar to a fitness tracker, that shines green LED light through the user’s skin and underlying blood vessels. By analyzing how much of this light is absorbed by the blood and how much is reflected the bottom of the device, the wearer’s heart rate can be continuously measured in real-time.
Papini and colleagues suggest that changes in heart rate may correspond to changes in breathing caused by sleep apnea. If so, patients could wear the device comfortably for multiple nights while sleeping in their own beds, which could provide more and better data than if they just spent a night in a sleep clinic and hooked up to multiple sensors.
The scientists started using the device to monitor the heart rate and pulse amplitude of 250 volunteers, some known to have sleep apnea and others not. This data is then used to train deep learning-based algorithms.
The algorithms were then able to match apparent changes in heart rate/pulse amplitude to apnea-induced breathing events, and they also learned to filter out distracting “background noise” such as body movements. Therefore, it is possible to calculate what is known as the “apnea-apnea index” for each individual – the number of abnormal breathing events per hour of sleep.
When the device and algorithm were tested on an additional 250 volunteers, each person’s calculated index closely matched those obtained using traditional sensors of the type commonly used in sleep clinics.
Professor Sebastiaan Overeem, Papini’s principal supervisor, said: “Hopefully this research will lead to new techniques that, in addition to better diagnosis, can also examine the efficiency of treatment in patients with sleep disorders. And importantly, the device can be used at home and Can be used for a long time.”