Journal of Sleep Research最新文献

The transition from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep is considered a transitional or intermediate stage (IS), characterised by high amplitude spindles in the frontal cortex and theta activity in the occipital cortex. Early reports in rats showed an IS lasting from 1 to 5 s, but recent studies suggested a longer duration of this stage of up to 20 s. To further characterise the IS, we analysed its spectral characteristics on electrocorticogram (ECoG) recordings of the olfactory bulb (OB), primary motor (M1), primary somatosensory (S1), and secondary visual cortex (V2) in 12 Wistar male adult rats. By comparing the IS with consolidated NREM/REM epochs, our results reveal that the IS has specific power spectral patterns that fall out of the NREM and REM sleep state power distribution. Specifically, the main findings were that sigma (11-16 Hz) power in OB, M1, S1, and V2 increased during the IS compared with NREM and REM sleep, which started first in the frontal part of the brain (OB -54 s, M1 -53 s) prior to the last spindle occurrence. The beta band (17-30 Hz) power showed a similar pattern to that of the sigma band, starting -54 s before the last spindle occurrence in the M1 cortex. Notably, sigma infraslow coupling (~0.02 Hz) increased during the IS but occurred at a slower frequency (~0.01 Hz) compared with NREM sleep. Thus, we argue that the NREM to REM transition contains its own local spectral profile, in accordance with previous reports, and is more extended than described previously.

Preschool children often have problems in remembering to carry out a planned behaviour. This study investigated the impact of napping on episodic foresight (planning for future events) and prospective memory (remembering to perform an action in the future) in 2-3-year-old children. In a quasi-experimental design, we compared children who napped (nap condition, n = 20) after receiving information about an upcoming problem (episodic foresight task) and a delayed intention (prospective memory task) with those who stayed awake (wake condition, n = 43). We hypothesised that napping would improve performance in the episodic foresight and the prospective memory tasks. Contrary to the hypothesis, napping did not significantly affect children's episodic foresight or prospective memory performance, even after controlling for the group difference in age. Task performance was primarily explained by memory effects and age. Further research that incorporates stricter controls and evaluates pre-nap memory strength is necessary fully to elucidate the complex interplay between napping, age, episodic foresight, and prospective memory performance in young children.

Insomnia has been suggested as a potential modulator of systemic inflammation. However, few studies have examined the longitudinal association between insomnia and inflammation as well as the role of sex differences, despite accumulating evidence of the vulnerability of women to immune consequences of disturbed sleep. In this study, we tested the association between self-reported insomnia symptoms and serum C-reactive protein, a marker of systemic inflammation, at 1-year follow-up, in 54 outpatients with inflammatory bowel disease (52.81 ± 16.09, 40.7% women). Insomnia symptoms were measured using the Insomnia Severity Index. After controlling for baseline inflammation and health variables, longitudinal moderated regression analysis showed that baseline insomnia symptoms predicted C-reactive protein levels at follow-up in women (β = 0.416, p = 0.014), but not in men (β = -0.179, p = 0.212). Results were not influenced by sex differences in insomnia severity or C-reactive protein levels. This study suggests insomnia symptoms may partially influence systemic inflammation in women with inflammatory bowel disease. Sex-specific psychological, immune and neuroendocrine pathways linking sleep to inflammation should be further elucidated.

Restless legs syndrome (RLS) is a highly prevalent condition that significantly disrupts sleep and causes reduced quality of life. While previous RLS research has mainly focused on the pharmacological treatment, this study presents the first instrument to measure self-care, the RLS-Self-care Behaviour questionnaire (RLS-ScBq). Self-care, defined as an active decision-making process, can empower patients to effectively participate in their own healthcare through awareness, self-control, and self-reliance to cope with their disease. Self-care can in a RLS context include actions such as physical exercise, meditation, and massage. Hence, the aim of this study is to explore the psychometric properties of the RLS-ScBq in patients with RLS. A cross-sectional design, including 788 patients with RLS (65% women, mean age 70.8 years, [standard deviation (SD) =11.4]) was used. Sociodemographics, comorbidities, and RLS-related treatment data, including insomnia symptoms (i.e., Insomnia Severity Index), daytime sleepiness (i.e., Epworth Sleepiness Scale) and RLS symptoms (i.e., RLS-6 scale) were collected. The validity and reliability of the RLS-ScBq were investigated using exploratory factor analysis and Rasch models. The two-factor solution (i.e., physical, and mental actions) showed an explained variance of 32.33% for The Self-care Behaviour Frequency part and 36.28% for The Benefit of Self-care Behaviour part. The internal consistency measured by Cronbach's α was 0.57 and 0.60, and McDonald's ω was 0.60 and 0.67, respectively. No differential item functioning was identified for gender, age, insomnia, daytime sleepiness, or RLS severity. The eight-item RLS-ScBq can serve as a tool enabling healthcare personnel to explore use and benefit of self-care activities in patients with RLS.

Restless legs syndrome is usually associated with periodic limb movements during sleep, which are defined as repetitive, stereotyped movements in sleep. Changes in spectral analysis of electroencephalography and heart rate were shown to be associated with periodic limb movements during sleep and non-periodic leg movements in sleep. Considering the circadian distribution of symptoms of restless legs syndrome, we investigated spectral electroencephalography and heart rate accompanying periodic limb movements, isolated leg movements and short-interval leg movements during suggested immobilization test. The mean age of 53 patients was 51.9 ± 13 years, 54.7% were females. Prominent increases in electroencephalography activation were associated with periodic limb movements, isolated leg movements and short-interval leg movements during the suggested immobilization test, which were significant in all spectral bands (p < 0.001). An increase in all electroencephalography bands started ~10 s before periodic limb movements, isolated leg movements and short-interval leg movements; increases in delta and theta band activities ended ~10 s after the movements, while increases in alpha and beta band activities lasted for about ~20 s. Maximum increases in delta, theta, alpha and beta bands were all observed after periodic limb movements and short-interval leg movements, but before isolated leg movements in theta and alpha bands, and after isolated leg movements in delta and beta bands. A notably longer increase in alpha and beta bands was evident for periodic limb movements and short-interval leg movements. An increase in heart rate was prominent at 4-12 s after movement onset in short-interval leg movements, being significantly higher than those associated with periodic limb movements and isolated leg movements. Our study shows that, in patients with restless legs syndrome, periodic limb movements, isolated leg movements and short-interval leg movements during suggested immobilization test are associated with prominent cortical and cardiac activation, which warrants confirmation in larger restless legs syndrome cohorts and requires long-term follow-up studies to delineate its possible clinical consequences.

Although emerging research suggests insomnia is a significant problem among people with eating disorders, little is known about how insomnia symptoms may serve as risk factors for eating disorder symptoms, treatment outcome, and relapse. University students with non-low-weight eating disorders (N = 89) completed a mobile guided self-help cognitive behavioural intervention for eating disorders. Insomnia and binge-eating symptoms were assessed at pre-treatment and end-of-treatment using the Insomnia Severity Index and Eating Pathology Symptoms Inventory. Multiply imputed datasets were used to test associations between insomnia and binge eating before, during and after treatment. Insomnia was positively associated with binge-eating symptoms prior to treatment (r = 0.47). Baseline insomnia symptoms were associated with binge-eating symptoms at end-of-treatment (est = 0.269). Eating disorder treatment modestly reduced insomnia (d = -0.38); however, about half of people with clinically significant insomnia prior to treatment remained symptomatic. Insomnia symptoms and binge-eating symptoms did not change concurrently during treatment. Overall, results support an association between insomnia and binge eating. Although eating disorder treatment may impact insomnia, many individuals remained symptomatic for sleep problems, suggesting the need for follow-up treatments, such as cognitive behavioural therapy for insomnia, or the development of integrated insomnia-eating disorder treatments. Future studies are needed to examine causal links between insomnia and eating disorder symptoms, and test if insomnia predicts relapse after eating disorder treatment.

Obstructive sleep apnea diagnosis is based on the manual scoring of respiratory events. The agreement in the manual scoring of the respiratory events lacks an in-depth investigation as most of the previous studies reported only the apnea-hypopnea index or overall agreement, and not temporal, second-by-second or event subtype agreement. We hypothesized the temporal and subtype agreement to be low because the event duration or subtypes are not generally considered in current clinical practice. The data comprised 50 polysomnography recordings scored by 10 experts. The respiratory event agreement between the scorers was calculated using kappa statistics in a second-by-second manner. Obstructive sleep apnea severity categories (no obstructive sleep apnea/mild/moderate/severe) were compared between scorers. The Fleiss' kappa value for binary (event/no event) respiratory event scorings was 0.32. When calculated separately within N1, N2, N3 and R, the Fleiss' kappa values were 0.12, 0.23, 0.22 and 0.23, respectively. Binary analysis conducted separately for the event subtypes showed the highest Fleiss' kappa for hypopneas to be 0.26. In 34% of the participants, the obstructive sleep apnea severity category was the same regardless of the scorer, whereas in the rest of the participants the category changed depending on the scorer. Our findings indicate that the agreement of manual scoring of respiratory events depends on the event type and sleep stage. The manual scoring has discrepancies, and these differences affect the obstructive sleep apnea diagnosis. This is an alarming finding, as ultimately these differences in the scorings affect treatment decisions.

Pregnant women benefit greatly from exercise due to its powerful impact on maternal and perinatal outcomes. The purpose of our study was to assess whether exercise improves objective sleep quality in pregnant women suffering from restless legs syndrome. This cross-sectional study is based on data from a large, naturalistic, consecutive cohort study in pregnant women recruited by four sleep centres, in Bologna, Milan and Turin (Italy), and Lugano (Switzerland), named the Life-ON study. Objective sleep parameters of 316 pregnant women were measured using polysomnographic recordings during the second trimester of pregnancy, and a self-reported assessment was used to evaluate physical activity. Pregnant women with restless legs syndrome (n = 91) who engaged in physical activity (n = 28) experienced better sleep efficiency (84.20% versus 82.10%, p = 0.01), less stage 1 sleep (10.50% versus 11.40%, p = 0.04) and wake after sleep onset (52.20 min versus 76.40 min, p ≤ 0.001), as well as reduced periodic leg movements during sleep (5.50 per hr versus 16.40 per hr, p < 0.001) when compared with the sedentary restless legs syndrome group (n = 63). Sleep structure was also better conserved in physically active pregnant women without restless legs syndrome compared with the inactive restless legs syndrome negative group. Overall, this study provides further evidence of the benefits of physical activity in pregnant women by illustrating its positive impact on sleep structure.

Clozapine is effective in treatment-resistant schizophrenia but with adverse effects including sedation. Excessive daytime sleepiness, a symptom of hypersomnolence, is the most frequently reported subjective side-effect. The aim of this systematic review was to synthesise the literature evaluating the impact of clozapine on the objective assessment of hypersomnolence in people with schizophrenia. We systematically searched databases for articles evaluating hypersomnolence with electrophysiological or psychomotor/cognitive measures in clozapine-treated patients with schizophrenia. Objective assessment of hypersomnolence was evaluated in six studies. All studies using polysomnography (PSG) found significantly longer total sleep time and shorter sleep onset latency in patients treated with clozapine at initiation of clozapine. The study with the multiple sleep latency test (MSLT) also found a shorter sleep onset latency. These observations did not persist 4-6 weeks after treatment initiation. Further investigations are needed. Longer total sleep time should be investigated with standardised long-term PSG to investigate excessive sleep quantity. Shorter sleep onset latency should be investigated with the MSLT or the maintenance of wakefulness test to investigate the excessive propensity to fall asleep or ability to stay awake. Lastly, sleep inertia should be investigated specifically in the morning.