Automatic slow eye movement (SEM) detection of sleep onset in patients with obstructive sleep apnea syndrome (OSAS): comparison between multiple sleep latency test (MSLT) and maintenance of wakefulness test (MWT).

OBJECTIVE

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

METHODS

We compared sleep latencies obtained upon standard analysis of MSLT and MWT recordings with automatically detected SEM latencies in a population of 20 severe OSAS patients that randomly underwent the two tests 1 week apart.

RESULTS

Eight of 20 OSAS patients had EDS as answered by the Epworth Sleepiness Scale (ESS). Mean SEM latency performed comparably to standard sleep onset in both the MSLT (6.4+/-5.5 min versus 7.4+/-5.1 min, p=0.25) and the MWT (25.2+/-14.5 min versus 24.4+/-14.0 min, p=0.45) settings. Mean SEM latency significantly correlated with the sleep latency at the MSLT (r=0.52, p<0.05) and at the MWT (r=0.74, p<0.001). Finally, the Epworth Sleepiness Scale score correlated with SEM latency at the MWT (r=-0.62, p<0.01), but not at the MSLT.

CONCLUSIONS

Automatic SEM detection performed comparably to standard polysomnographic assessment of sleep onset, thus providing a simplified technical requirement for the MSLT and the MWT. Further studies are warranted to evaluate SEM detection of sleep onset in other sleep disorders with excessive daytime sleepiness.