Background and purpose: The aims of this study were to determine the prevalence of sleep-state misperception and to identify any differences in the clinical characteristics of primary insomniacs with and without misperception.
Methods: In total, 250 adult primary insomniacs were enrolled whose objective total sleep time (TST) was more than 120 min, as assessed by full-night polysomnography. Sleep state misperception was defined objectively as a TST of at least 6.5 h and an objective sleep efficiency (SE) of at least 85%.
Results: The prevalence of sleep-state misperception in primary insomniacs was 26.4%. The (low) quality of sleep and psychiatric parameters were similar in the two groups, although the objective sleep architecture was relatively normal for the misperception group. Multivariate analysis revealed that both SE and sleep quality were significant factors associated with subjective TST in the misperception group, while only SE was significant in those without misperception. Subjective TST was a significant effect factor with respect to sleep quality in the misperception group, while the Beck Depression Inventory-2 score and age were significant factors in those without misperception.
Conclusions: The clinical characteristics of patients with sleep-state misperception differed from those without this condition. This suggests that these two groups should be separated and the treatment goals tailored specifically to each.
Keywords: insomnia; sleep disorders; sleep-state misperception.