Comparative analysis of sleep state perception between insomniacs and good sleepers

Objective To analyse the discrepancy of sleep state perception as well as objective sleep measures between insomniacs and good sleepers, moreover, approach to the traits of sleep state perception in insomniacs. Methods Subjective measures of sleep state perception were obtained from a sleep diary (morning questionnaire) and objective measures from polysomnography (PSG). Insomnia Severity Index (ISI), Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) were used to evaluate the severity of insomnia and preliminary related status. Results Both subjective parameters of sleep state perception and objective measures were significantly different between the insomniacs and controls (P 0.01, for all). Prolonged sleep latency, increased wakefulness time after sleep onset, lower sleep efficiency and decreased total sleep duration were found in insomnia group. The difference of sleep state evaluation similarly existed in both insomnia group and control group (P 0.05, for all), but more prominent in insomniacs (P 0.05), which overestimated their sleep latency particularly. The misperception from sleep state was bilateral in insomniacs. The scores of SAS as well as SDS in insomnia group exceeded control group (P 0.01), and kept a positive correlation with ISI (P 0.01). Especially, the scores of SAS correlated with subjective sleep latency (P 0.01). Conclusion Insomniacs were poor in sleep quality. They had a similar misperception in sleep state compared with good sleepers, but more incongruity between subjective parameters and objective items. Sleep state misperception in insomniacs included bilateral aspect, underestimated their actual sleep state (exaggerated their sleep disorder) or overestimated them (ignored nocturnal sleep deficiency). With correlation test, anxiety as a factor, may directly relate to subjective sleep latency misperception.