FAQ for Clinics

How accurate is Belun Ring as compared to polysomnography?

A diagnostic algorithm combining STOP-Bang cutoff of 5 and bAHI cutoff of
15 events/h demonstrated an accuracy, sensitivity, specificity of 0.938 [95% CI, 0.828–0.987], 0.944 [95% CI, 0.727–0.999], and 0.933 [95% CI, 0.779–0.992], respectively, for the diagnosis of moderate to severe OSA.

Reference: Yeh E, Wong E, Tsai C-W, Gu W, Chen PL, Leung L, et al. (2021) Detection of obstructive sleep apnea using Belun Sleep Platform wearable with neural network-based algorithm and its combined use with STOP-Bang questionnaire. PLoS ONE 16(10): e0258040. https://doi.org/10.1371/journal.pone.0258040

Is polysomnography necessary after Belun Ring sleep test?

American Academy of Sleep Medicine (AASM) recommends home sleep test (HST) for symptomatic and uncomplicated population. 

If a patient has a high pre-test probability of OSA, and HST gives AHI > 15, consider for treatment options; If a patient has a high pre-test probability of OSA, and HST gives AHI < 5, consider for further investigation. 

Belun Ring does not replace PSG, but offers a convenient and accurate HST for symptomatic screening and treatment evaluation. 

How can Belun Ring determine apnea/hypopnea without respiratory channels (e.g. airflow and effort to breathe)?

Belun's AI algorithm was trained with >8000 PSG data. The algorithm determines apnea/hypopnea events from the patient's pattern of SpO2, pulse rate, heart rate variability and motion.

How can Belun Ring determine sleep stage and total sleep time without EEG?

Belun's AI algorithm was trained with >8000 PSG data. The algorithm determines sleep stage and total sleep time from the patient's pattern of SpO2, pulse rate, heart rate variability and motion.

How does Belun Ring determine Autonomic Nervous System (ANS) balance?

Stress becomes visible through increased activation levels of the body. Activation levels are governed by the autonomic nervous system (ANS) which regulates gastrointestinal, endocrine, cardiovascular and pulmonary systems to facilitate the demands of daily life. The two divisions of the ANS are the sympathetic and parasympathetic divisions. 

Parasympathetic nervous system (PNS) restores and maintains the body’s resting condition. Recovery means reduced activation levels in the body in the absence of internal and external stress factors. During recovery, parasympathetic (vagal) activations dominate the ANS and psychophysiological resources are restored. Indicators of recovery include low HR and high HRV.

Sympathetic nervous system (SNS) prepares the body to meet challenges. Sympathetic nervous activity accelerates bodily functions (i.e., physiological stress reaction). The stress response results in increased activation of stress-hormone secretions (cortisol, catecholamines), increased blood pressure and HR and decreased HRV.

ANS function can be assessed noninvasively using HR and HRV.

What is the difference between Belun Ring and overnight pulse oximeter?

Belun Ring has additional channels including actigraphy and heart rate variability for determining the total sleep time instead of using recording time for calculating ODI and AHI. 

Standard oximeters cannot determine sleep time and hence underestimate the number of denaturation events per hour. 

What is the difference between Belun Ring and consumer wristbands/smartwatches?

Belun Ring is FDA cleared medical device. Accuracy and reliability has been demonstrated to the regulatory body, and also proven in clinical studies.  

Most of the wristbands and smartwatches on the market do not pass the requirements on accuracy. The data given by these consumer gadgets cannot be used for clinical applications.