Fc. Yen et al., A NONINVASIVE TECHNIQUE FOR DETECTING OBSTRUCTIVE AND CENTRAL SLEEP-APNEA, IEEE transactions on biomedical engineering, 44(12), 1997, pp. 1262-1268
A new noninvasive method to detect obstructive and central sleep apnea
[(OSA) and (CSA)] events is described. Data were collected from ten v
olunteer subjects with a previous diagnosis of OSA while they were tit
rated for continuous positive airway pressure (CPAP) therapy. Apneic e
vents were identify by analyzing of estimated airway impedance determi
ned from pressure and airflow signals delivered from CPAP. To enhance
performance of this technique, a single-frequency (5 Hz with 0.5 cmH(2
)O peak-to-peak amplitude) probing signal was superimposed on the appl
ied CPAP pressure. The results indicated that estimated airway impedan
ce during OSA (mean: 17.9, SD: 3.4, N = 50) was significantly higher t
hen during CSA (mean: 4.1, SD: 1.7, N = 50). When the estimated impeda
nce of OSA and CSA events were compared to a fixed threshold, 100% of
all events can be correctly categorized. These results indicate that i
t may be possible to diagnose OSA and CSA noninvasively based upon thi
s technique. The instrument and the algorithm required are relatively
simple and can be incorporated in a home-based device. If this method
was used for prescreening apnea patients, it could reduce cost, waitin
g time, and discomfort associated with traditional diagnostic procedur
es.