Excessive daytime somnolence in women with abnormal respiratory efforts during sleep.

An abnormal level of respiratory efforts, indicated by significant increase in peak negative esophageal pressure (Pes), can be associated with daytime somnolence in snoring pre-menopausal women. No drop in oxygen saturation (SaO2) or visual evidence of transient electroencephalographic (EEG) arousals can be found at repeat polysomnography. Nasal continuous positive airway pressure (CPAP) titrated on Pes measurements eliminates somnolence.