LAUSR

We previously showed that AHI scored in respiratory polygraphy (AHI PG:24.2±21.5), in PG associated with the automatic analysis of an EEG channel (AHI PG+:29.4±23.7) and in PSG (AHI PSG 31.0±24.6) were significantly different (p To explore the difference between AHI PG and AHI PSG, we studied 25 patients (47yrs,12M,33kg/m2) suspected of OSAS by ambulatory PSG (CID-LXe by Cidelec) with an additional EEG (CzPz). 2 blinded somnologists(S1, S2) scored: first respiratory events in PG on total recorded time (TRT) and then in PG+ with periods of sleep and arousals determined on CzPz by the validated algorithm ASEEGA(A) and finally in PSG (AASM criteria). Epoch-by-epoch Wake/Sleep concordance between A and the consensus of S1&S2 was 96% (Kappa=.8). 4/25 patients (49 to 80yrs and BMI 25 to 46kg/m2) showed significant amount of apneas and hypopneas during wake. Their sleep efficiencies were 82 to 89% and AHI PSG ranged from 45 to 83/hr. Consensual (S1, S2, A) waking time during TRT ranged from 55 to 162 min. The wake AHI (number of events in wakefulness/total waking time) ranged from 20 to 53/hr. Waking events were obstructive hypopneas in 1 patient diagnosed with pure obstructive sleep apnea, central in 1 patient with mixed SA (39% central events in PSG) and in 2 with predominantly central apneas (68 and 92% central in PSG). 1 patient with Cheyne-Stokes had heart failure. Waking events ocurred in 4/25 patients and were either obstructive hypopneas in pure OSAS or central apneas in mixed or central SAS. This result, if confirmed on larger cohorts, could further explain the difference between AHI PG and AHI PSG.