Self-reported excessive daytime somnolence and impaired respiration in sleep.

The purpose of this study was to determine which measures of impaired respiration in sleep relate to self-reported excessive daytime somnolence (EDS). Previous studies conflict regarding the relative importance of arterial hypoxemia and brief awakenings in relating to EDS. A group of 37 elderly clinic patients with complaints of snoring, a clinical diagnosis of sleep apnea, and varying degrees of self-reported somnolence were evaluated polysomnographically and psychometrically. Results showed that a subgroup of somnolent patients were characterized by more severe oxygen desaturations relative to nonsomnolent patients. These differences were obtained even when obesity was controlled. Psychologic symptoms related to the symptom of EDS but not to the sleep measures. This suggested that patients were clearly distressed by their hypersomnolence, but that individual differences played a major role in how the distress was manifested.