Diagnostic Performance of a Combined Reflective Photoplethysmography and Ultra-Wideband Radar Device for Obstructive Sleep Apnea: Comparison with Polysomnography.

OBJECTIVE

Obstructive sleep apnea (OSA) exhibits high prevalence, yet limited polysomnography (PSG) resources highlight an urgent need for large scale screening. This study assessed the diagnostic efficacy of a combined reflective photoplethysmography and ultra-wideband radar device (Zhao-Guan wireless monitoring system, ZG-Sys) compared to PSG. The aims were to establish ZG-Sys OSA severity cutoff values and define its clinical implementation prospects.

METHODS

This prospective, open-label diagnostic study was conducted in a sleep center, collecting 433 valid datasets for suspected sleep disorders from June 2023 to April 2024, via synchronous Type 1 PSG and ZG-Sys monitoring. ZG-Sys consists of a ring-style pulse oximeter (Circul) and an IR-UWB radar device (OrbSense). Statistical analysis utilized Spearman rank correlation, Bland-Altman analysis, and Receiver Operating Characteristic (ROC) curves to evaluate agreement and determine optimal ZG-AHI cutoff values against PSG-AHI standards (5, 15, and 30 events/h).

RESULTS

ZG-AHI showed a significant correlation with PSG-AHI (Spearman r = 0.800, ICC = 0.908, P < 0.001). The optimal ZG-AHI cutoff for detecting moderate-to-severe OSA (PSG-AHI ≥15) was 20.8 events/h, yielding a high area under the curve (AUC) of 0.943. ZG-Sys demonstrated high sensitivity (89.10-90.80%) and specificity (85.30-88.80%) for identifying moderate-to-severe OSA. Although consistency was good across multiple sleep disorders (eg, parasomnias), weaker correlations were observed in the continuous positive airway pressure (CPAP) treatment group.

CONCLUSION

ZG-Sys demonstrated moderate consistency with PSG across multiple sleep disorders, proving significant clinical value for screening and diagnosing moderate to severe OSA. Featuring simple charging, reusability, and real-time monitoring capabilities, ZG-Sys shows potential for clinical screening in sleep center settings.