Validation of a seven-channel device for ambulatory screening of obstructive sleep apnea. Part 2: Simultaneous polysomnography

Purpose: For some time, the ambulatory diagnosis of respiratory disturbance s during sleep has included the use of seven-channel recording units. One o f these systems is the POLY-MESAM unit (MAP, Germany). Methods:The aim of the present study was to validate the POLY-MESAM system by simultaneously performing 12-channel polysomnography. Forty-nine patient s (45 males and 4 females) with different severities of obstructive sleep-r elated breathing disorders were included. Obstructive sleep apnea was diagn osed,when an apnea-hypopnea index (AHI) >15 was found by polysomnography. T he sensitivity and specificity for POLY-MESAM were calculated on the basis of the polysomnographic AHI. Results:The sensitivity of POLY-MESAM far detecting patients with an AHI >1 5 was 86.4% and the specificity was 100%. Conclusions:The POLY-MESAM system was easy to use. The sensitivity and spec ificity for the MESAM4 unit were 92% and 97% respectively, which was simila r to POLY-MESAM. Additionally, POLY-MESAM provided the possibility for dist inguishing the different kinds of apneas. Thus, POLY-MESAM was considered t o be a useful development of the previous MESAM4 unit. In some cases, use o f the POLY-MESAM unit resulted in underestimation of the AHI. POLY-MESAM pr oduced false-negative results in patients with mild to moderate OSA. This f inding was reflected in the relatively poorer sensitivity of the method (86 .4%). Cardiorespiratory sleep studies las possible with POLY-MESAM) are bes t limited to patients for whom the diagnosis of OSA is highly probable or a s a follow-up tool in selected circumstances.