Using Digital Recorder in Sleep Apnea Screening:  a Clinical Trial

Objectives: Obstructive sleep apnea (OSA) is a serious sleep disorder.The current standard in OSA diagnosis method is polysomnography (PSG) and respiratory polygraphy (RP) testing. RP requires an overnight hospital stay while physically connected to 10-15 channels of measurement. RP is expensive, inconvenient and requires the extensive involvement of a sleep specialist. In this study, we propose to use digital recorder to detect sleep apnea. The objectives of this study were to determine the applicability of the recording method in the detection of sleep anomalies and evaluate the sensitivity and specificity of the recording method compared with the conventional respiratory polygraphy method. Method: This clinical trial was conducted on 20 subjects. They were selected from patients presenting at the Respiratory department, Cho Ray Hospital with symptoms of snoring and sleep apnea, from 01/2011 to 05/2011. Subjects in the study slept over night at the hospital to be measured by respiratory polygraphy, this program identified apnea index (AI₁) of the patient. At the same time, snoring and breathing sounds were also recorded during sleep using a digital recorder. Sound forge pro 10 was used to define apnea index (AI₂) based on the digital recorder method. OSA patients were diagnosed according to apnea index by each method. Calculation of sensitivity and specificity was applied. Results:   Among the 20 subjects who matched the clinical selection criteria, 19 of them were diagnosed with OSA by respiratory polygraphy, there was only one negative case. According to the recording method, there were 17 positive cases and 3 negative ones. The recording method resulted in a sensitivity of 89.47% and a specificity of 100%. Conclusion: The digital recording method had the advantages of being  a  non-intrusive, unattended technique to screen OSA, using snore sound as the initial signal.