Comparison of Polysomnography and Cardiopulmonary Coupling in the Diagnosis of Insomnia, Obstructive Sleep Apnoea, or Comorbidity, a Pilot Study

Abstract

Objective: To verify the reliability of cardiopulmonary coupling (CPC) technology to diagnose chronic insomnia disorder (CID), obstructive sleep apnoea (OSA) and comorbid OSA with insomnia (COI). Methods: Data from 161 patients suffering from the three conditions were collected, and objective sleep status was assessed simultaneously by CPC and polysomnography (PSG). These patients were diagnosed according to the clinical symptoms and PSG results. The general data of the three groups were compared, and the agreement of AHI and sleep parameters between CPC and PSG was analysed by Bland-Altman agreement plots. Results: We found that, when AHI (events/h) ≥ 5, 10, 15, 20, 25 and 30 were used as the conditions for the diagnosis of OSA, the sensitivity was 82.7%, 63.5%, 67.3%, 84.6%, 71.9% and 61.5%; the specificity was 61.6%, 63.3%, 73.4%, 84.4%, 82.9% and 84.4%; and the area under the curve (AUC) was 0.792, 0.735, 0.787, 0.889, 0.884 and 0.861, respectively. Bland-Altman agreement plots for the sleep parameters were measured by PSG and CPC. Although 95% of the points of some graphs were within the consistency range, they were beyond the professionally acceptable threshold range. Conclusion: As a tool for rapid screening of OSA patients, the overall performance of CPC is acceptable in subjects with clinical suspicion of OSA, but the clinical interpretation of sleep parameter results obtained with CPC must be cautious, especially in insomnia state.