Acoustical screening for obstructive sleep apnea during wakefulness.

In this paper a new non-invasive method for screening patients with obstructive sleep apnea (OSA) during wakefulness is proposed. Eight people with OSA and eight non-apneic individuals participated in this study. The tracheal breath sound was recorded in supine and upright positions during both nose and mouth breathing maneuvers. Spectral analysis of the respiratory sound signals showed the variation in the average power of the sounds at different positions to be a characteristic feature discriminating the two groups. Using this feature, the OSA and non-apneic participants were classified by quadratic discriminant analysis (QDA). The specificity, sensitivity, and classification accuracy of the classifier were found to be 100%, 87.5%, and 95.75%, respectively. These results are encouraging for the use of the proposed method as a fast, simple and screening tool for diagnosis of OSA during wakefulness.