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Study objectives: To determine the recording capabilities of the POLY-MESAM (PM) unit (MAP; Martinsried, Germany), an American Sleep Disorders Association level III system, and to compare it with simultaneous 12-channel polysomnography in the sleep laboratory.
Measurements and results: Fifty-three patients (49 men and 4 women) with obstructive sleeprelated breathing disorders of varying severity were included. The apnea-hypopnea indexes (AHIs) obtained using the two methods differed significantly from each other, although the correlation was close. The PM unit produced false-negative results in patients with mild to moderate obstructive sleep apnea (OSA). The sensitivity of the PM unit in detecting patients with an AHI > 10 was 92%, while the specificity was 96.3%.
Conclusions: The correlation of AHIs obtained with polysomnography and with the PM unit is close. However, in some cases, the PM may underestimate OSA parameters. The PM unit produces false-negative results in patients with mild to moderate OSA. While inpatient polysomnography remains the "gold standard," the PM unit may provide an inexpensive alternative in some special cases. (CHEST 2000; 117:1613-1618)
Key words: ambulatory recording; POLY-MESAM; sleep apnea; validation
Abbreviations: AM = apnea-hypopnea index; Al = apnea index; ASDA = American Sleep Disorders Association; HI = hypopnea index; ODI = oxygen desaturation index; OSA = obstructive sleep apnea; PM = POLY-MESAM; TIB = time in bed; TST = total sleeping time
The "gold standard" for the diagnosis of respiratory abnormalities during sleep is a full night of sleep for the patient while being observed and recorded in the laboratory with polysomnography. This is classified by the American Sleep Disorders Association (ASDA) as a level I sleep study.l This procedure is both labor and resource intensive, and, so, alternatives are desirable. A variety of devices that can be used at home are available, and these have been categorized by the ASDA into the following three levels.
1. Level II studies. These are comprehensive studies using portable polysomnography devices that measure both respiratory and sleep variables.
2. Level III studies. These are studies using unattended recording devices (modified portable sleep apnea testing) that allow for the assessment of cardiorespiratory variables only.
3. Level IV studies. These studies comprise continuous single or double bioparameter recordings.
One level III device that measures thoracic and abdominal respiratory movements...