[Sleepiness, continuous positive airway pressure and the obstructive sleep apnea hypopnea syndrome].

Excessive daytime sleepiness is a major symptom in cases of the obstructive sleep apnea-hypopnea syndrome. Most often, it is vastly improved by treatment with continuous positive airway pressure (CPAP). The most effective way to confirm its disappearance is through wakefulness maintenance testing. If residual sleepiness remains, despite CPAP, further diagnostic investigation must be carried out. Firstly, it must be assessed whether the treatment is fully effective (apnea hypopnea index<10/h) by examining flow limitations under treatment (polysomnography) and whether it is sufficiently used (>6h/night). If this is the case, the possibility of other situations responsible for excessive daytime sleepiness must be reviewed and eliminated, whether they are depression, sleep insufficiency, use of intoxicants, obesity, restless legs syndrome, or circadian sleep-wake cycle disorder. If not, the multiple sleep latency tests make it possible to assess sleepiness (latency<8min) and can lead to a diagnosis of central hypersomnia (narcolepsy, idiopathic hypersomnia, hypersomnia due to a medical pathology). In some rare cases (about 6% of patients) investigations will reveal central hypersomnia due to the obstructive sleep apnea-hypopnea syndrome or "lesional" hypersomnia due to intermittent hypoxia. Since 2011, medications treating excessive sleepiness have had marketing authorization only for narcolepsy in France. However, they can be administered by way of derogation to other neurological hypersomnias on prescription by a reference centre or a centre with expertise in hypersomnia.