Sleep perception in insomniacs, sleep-disordered breathing patients, and healthy volunteers--an important biologic parameter of sleep.

BACKGROUND: The mechanisms involved in sleep perception are not widely known. Therefore, we believe that investigating this phenomenon is the best way to understand some of the mechanisms involved in several sleep disturbances, particularly insomnias.
OBJECTIVE: The objective of our study was to evaluate sleep perception in insomniacs, sleep-disordered breathing (SDB) patients, and healthy volunteers. Our hypothesis was that insomniacs have less sleep perception than healthy individuals and patients with sleep respiratory disorders.
METHODS: We studied 199 individuals who were divided into the following four groups: (1) insomnia group; (2) patients with sleep-disordered breathing; (3) patients with insomnia complaints and an associated sleep respiratory disorder; and (4) healthy individuals with no sleep complaints. All patients were subjected to polysomnography (PSG) followed by a questionnaire addressing their perception about the previous night's sleep. In addition to analysis of all sleep parameters, we determined sleep perception as the percentage of the ratio between total sleep time perceived by the patient and the total sleep time obtained by PSG.
RESULTS: Sleep perception was significantly lower in insomnia patients than in sleep-disordered breathing patients or the normal group. In addition, no significant differences across the four groups were observed in sleep efficiency and total sleep time.
CONCLUSIONS: The results showed that the reported sleep perception of insomniacs is lower than that of sleep-disordered breathing patients or normal individuals. We believe that sleep perception is as important as other commonly measured parameters, such as sleep efficiency.