Current Sleep Medicine Reports最新文献

Purpose of review: I review the current status of the hypothesis that sleep is critically involved in memory consolidation and conclude that there are major methodological problems with the studies used to support this hypothesis.

Recent findings: Memory consolidation is similar in quiet waking and sleep (Humiston GB, Tucker MA, Summer T, Wamsley EJ. Sci Rep 18;9(1):19345, 2019), and suppression of REM sleep for long periods is compatible with learning and highly adaptive behavior (Lyamin OI, Korneva SM, Obukhova ED, Mukhametov LM, Siegel JM. Dokl Biol Sci 463:211-4, 2015; Lyamin OI, Kosenko PO, Korneva SM, Vyssotski AL, Mukhametov LM, Siegel JM. Current Biology 28(12):2000-5, 2018); despite their considerable abilities to navigate and remember, African elephants have very small amount of sleep, and learning interference effects have not been adequately controlled for in studies purporting to show sleep-dependent memory consolidation (Sosic-Vasic Z, Hille K, Kroner J, Spitzer M, Kornmeier J. Frontiers in psychology 9:82, 2018; Yonelinas AP, Ranganath C, Ekstrom AD, Wiltgen BJ. Nat Rev Neurosci 20(6):364-75, 2019).

Summary: Memory consolidation clearly occurs in both sleep and waking. Whether, and the extent to which, consolidation might differ in these two states has not been conclusively determined.

Purpose of review: This review summarizes recent literature on the heritability of sleep and sleep disorders in childhood and adolescence. We also identify gaps in the literature and priorities for future research.

Recent findings: Findings indicate that age, measurement method, reporter, and timing of sleep measurements can influence heritability estimates. Recent genome-wide association studies (GWAS) have identified differences in the heritability of sleep problems when ancestral differences are considered, but sample sizes are small compared to adult GWAS. Most studies focus on sleep variables in the full range rather than on disorder. Studies using objective measures of sleep typically comprised small samples.

Summary: Current evidence demonstrates a wide range of heritability estimates across sleep phenotypes in childhood and adolescence, but research in larger samples, particularly using objective sleep measures and GWAS, is needed. Further understanding of environmental mechanisms and the interaction between genes and environment is key for future research.

Purpose of review: People with isolated REM (rapid eye movement) sleep behavior disorder (iRBD) have a high lifetime risk of developing a neurodegenerative disease, including dementia, but disclosure of this risk remains controversial. Herein, we summarize this controversy and provide guidance on disclosure.

Recent findings: Neurodegeneration risk disclosure in iRBD is controversial because of a long latency to disease onset and a lack of preventative strategies. Balancing the relevant ethical principles of beneficence, nonmaleficence, and autonomy is challenging. Although there are few data on disclosure in iRBD, evidence from discussing risk in other diseases with dementia provides some guidance.

Summary: We provide an approach to risk disclosure for patients with iRBD. Patients should be asked if they want to know about future risks. If so, disclosure should be patient centered, focusing on what might happen. Discussion should occur early to give patients time to prepare for the future and consider participating in research.

Purpose of review: Response to cognitive-behavioral therapy for insomnia (CBT-I) is variable across individuals, and specialty insomnia clinics that provide CBT-I are few. To personalize insomnia treatments and maximize the cost-effectiveness of CBT-I, this paper reviews the conceptual model and content of CBT-I and the predictors of adherence/response to CBT-I as the basis for understanding who is most likely to benefit from CBT-I.

Recent findings: Specific patient-related attributes that predict benefit from CBT-I include (1) presence of maladaptive behaviors that serve as perpetuating factors of insomnia; (2) greater motivation to pursue therapy and higher treatment expectancies regarding CBT-I; (3) reduced use of hypnotics; (4) longer sleep duration; and (5) adequately treated psychiatric comorbidities.

Summary: People presenting with chronic insomnia and these attributes may warrant prioritization in referral to behavioral insomnia clinics. Conversely, those who do not have such favorable characteristics may require interventions that address modifiable factors associated with poor adherence/response to CBT-I.

Purpose of review: Auditory stimulation is a technique that can enhance neural oscillations linked to overnight memory consolidation. In this review, we evaluate the impacts of auditory stimulation on the neural oscillations of sleep and associated memory processes in a variety of populations.

Recent findings: Cortical EEG recordings of slow-wave sleep (SWS) are characterised by two cardinal oscillations: slow oscillations (SOs) and sleep spindles. Auditory stimulation delivered in SWS enhances SOs and phase-coupled spindle activity in healthy children and adults, children with ADHD, adults with mild cognitive impairment and patients with major depression. Under certain conditions, auditory stimulation bolsters the benefits of SWS for memory consolidation, although further work is required to fully understand the factors affecting stimulation-related memory gains. Recent work has turned to rapid eye movement (REM) sleep, demonstrating that auditory stimulation can be used to manipulate REM sleep theta oscillations.

Summary: Auditory stimulation enhances oscillations linked to overnight memory processing and shows promise as a technique for enhancing the memory benefits of sleep.

Purpose of review: To present an up-to-date review and synthesis of findings about perinatal sleep development and function. I discuss landmark events in sleep ontogenesis, evidence that sleep promotes brain development and plasticity, and experimental considerations in this topic.

Recent findings: Mammalian sleep undergoes dramatic changes in expression and regulation during perinatal development. This includes a progressive decrease in rapid-eye-movement (REM) sleep time, corresponding increases in nonREM sleep and wake time, and the appearance of mature sleep regulatory processes (homeostatic and circadian). These developmental events coincide with periods of rapid brain maturation and heightened synaptic plasticity. The latter involve an initial experience-independent phase, when circuit development is guided by spontaneous activity, and later occurring critical periods, when these circuits are shaped by experience.

Summary: These ontogenetic changes suggest important interactions between sleep and brain development. More specifically, sleep may promote developmental programs of synaptogenesis and synaptic pruning and influence the opening and closing of critical periods of brain plasticity.

Purpose of review: Napping is a common behavior across age groups. While studies have shown a benefit of overnight sleep on memory consolidation, given differences in nap frequency, composition, and intent, it is important to consider whether naps serve a memory function across development and aging.

Recent findings: We review studies of the role of naps in declarative, emotional, and motor procedural memory consolidation across age groups. Recent findings in both developmental and aging populations find that naps benefit learning of many tasks but may require additional learning or sleep bouts compared to young adult populations. These studies have also identified variations in nap physiology based on the purpose of the nap, timing of the nap, or age.

Summary: These studies lend to our understanding of the function of sleep, and the potential for naps as an intervention for those with reduced nighttime sleep or learning impairments.