[Validating a 7-channel ambulatory polygraph unit. 2: Simultaneous polysomnography].

PURPOSE

For some time, the ambulatory diagnosis of respiratory disturbances during sleep has included the use of seven-channel recording units. One of 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 patients (45 males and 4 females) with different severities of obstructive sleep-related breathing disorders were included. Obstructive sleep apnea was diagnosed, when an apnea-hypopnea index (AHI) > 15 was found by polysomnography. The sensitivity and specificity for POLY-MESAM were calculated on the basis of the polysomnographic AHI.

RESULTS

The sensitivity of POLY-MESAM for detecting patients with an AHI > 15 was 86.4% and the specificity was 100%.

CONCLUSIONS

The POLY-MESAM system was easy to use. The sensitivity and specificity for the MESAM4 unit were 92% and 97% respectively, which was similar to POLY-MESAM. Additionally, POLY-MESAM provided the possibility for distinguishing the different kinds of apneas. Thus, POLY-MESAM was considered to be a useful development of the previous MESAM4 unit. In some cases, use of the POLY-MESAM unit resulted in underestimation of the AHI. POLY-MESAM produced false-negative results in patients with mild to moderate OSA. This finding was reflected in the relatively poorer sensitivity of the method (86.4%). Cardiorespiratory sleep studies (as possible with POLY-MESAM) are best limited to patients for whom the diagnosis of OSA is highly probable or as a follow-up tool in selected circumstances.