[Slow eye movement analysis in patients with obstructive sleep apnea/hypopnea syndrome]

To determine whether slow eye movement (SEM) analysis performed comparably to standard sleep onset criteria at the multiple sleep latency test (MSLT) and the maintenance of wakefulness test (MWT) in patients with obstructive sleep apnea/hyponea syndrome (OSAHS).

We compared SEM latencies with sleep latencies upon analysis of MSLT and MWT recordings artificially, in a population of 20 severe OSAHS patients that randomly underwent the 2 tests 2 days apart. They all answered the Epworth Sleepiness Scale.

Mean SEM latency was different from standard sleep onset in the MSLT [(4.2 ± 1.9) min vs (5.3 ± 2.0) min, P < 0.001], and the MWT [(12 ± 10) min vs (13 ± 10) min, P < 0.001]. Mean SEM latency correlated significantly with the sleep latency at the MSLT (r = 0.958, P < 0.001) and at the MWT (r = 0.997, P < 0.001). Finally, the Epworth Sleepiness Scale score correlated with SEM latency at the MSLT (r = -0.580, P = 0.007), but not at the MWT.

SEM latency was different from sleep latency that detected from EEG, but they correlated significantly with each other, thus providing a simplified way to evaluate sleepiness.