Evaluation of the POLYMESAM system in the diagnosis of obstructive sleep apnea syndrome

The reliability of a POLYMESAM (PM) instrument in the detection of ventilatory disorders and in the diagnosis of obstructive sleep apnea syndrome (OSAS) was evaluated in 50 subjects suspected for OSAS, simultaneously studied by polysomnography (PSG) in a sleep laboratory. Recordings were analysed by separate scorers, blinded to the results of the paired recording. The number of central (Ac), obstructive (Ao) or mixed apneas (Am), of hypopneas (H), and the total number of ventilatory disorders (AH) per hour of time in bed (TIB) calculated on the two recordings were significantly correlated. Bland and Altman analysis showed a good agreement between AH/TIB, Ac/TIB, Am/TIB and mean AH duration; a lower Ao/TIB at PM was mirrored by a higher H/TIB. Forty-two subjects had OSAS according to an apnea/hypopnea index (AHI) > or = 10 at PSG. Due to low sleep efficiency, AH/TIB was substantially lower than AHI. However an AH/TIB > or = 5 at PM showed a sensitivity of 100% and a specificity of 71.4%, while an AH/TIB > or = 10 showed a sensitivity of 95.2% and a specificity of 100%. In conclusion, PM proved reliable for recognition of the characteristics of ventilatory disorders and for diagnosis of OSAS.