Sleep, learning, and memory in human research using noninvasive neuroimaging techniques

The Association Between Sleep Health and a History of Cataract Surgery in the United States Based on the National Health and Nutrition Examination Survey (NHANES) 2005-2008

Background: The aim of this study was to assess the relationship between sleep-related variables (sleep duration, sleep trouble, and sleep disorder), comprehensive sleep patterns, and the reported history of cataract surgery in the U.S. population aged 20 years and older. Methods: We utilized data from the National Health and Nutrition Examination Survey (NHANES) 2005-2008 database. First, we analyzed the association between covariates and the reported history of cataract surgery using univariable Poisson regression. Subsequently, we constructed three models to evaluate the association between sleep-related variables and the reported history of cataract surgery using multivariable Poisson regression. Subgroup analyses were conducted to determine whether the association between sleep and the reported history of cataract surgery exhibited heterogeneity. Finally, we performed a sensitivity analysis to assess the stability of the results. Results: A total of 8591 participants were included in this study, among whom 774 had a history of cataract surgery. After adjusting for all covariates, participants experiencing sleep trouble had a higher prevalence of reported history of cataract surgery than participants without sleep trouble [PR = 1.40; 95%CI = (1.22, 1.62)]. Regarding combined sleep, participants with poor sleep patterns had a 36% higher prevalence of reported history of cataract surgery than those with healthy sleep patterns [PR = 1.36; 95%CI = (1.13, 1.64)]. The results of the sensitivity analysis indicate that the relationship between sleep patterns and the reported history of cataract surgery is robust. Conclusions: Sleep trouble and poor sleep patterns are positively linked to the high prevalence of a reported history of cataract surgery. Further research is needed to explore the underlying mechanisms.

Sleep and periodontal health

Sleep is fundamental for health and well-being. An adequate amount and quality of sleep is a cardinal component of a healthy lifestyle at the basis of the prevention of many non-communicable chronic diseases. Recent evidence suggests that sleep disorders, particularly obstructive sleep apnea, represent an emerging risk factor for periodontal health. This review article provides a critical appraisal of the existing literature concerning the association between sleep duration, sleep quality, sleep disorders in general, and obstructive sleep apnea with periodontal diseases, including gingivitis and periodontitis. The putative mechanisms underlying these associations are described as well as the potential clinical implications for diagnosis and treatment.

First-night effect reduces the beneficial effects of sleep on visual plasticity and modifies the underlying neurochemical processes

Individuals experience difficulty falling asleep in a new environment, termed the first night effect (FNE). However, the impact of the FNE on sleep-induced brain plasticity remains unclear. Here, using a within-subject design, we found that the FNE significantly reduces visual plasticity during sleep in young adults. Sleep-onset latency (SOL), an indicator of the FNE, was significantly longer during the first sleep session than the second session, confirming the FNE. We assessed performance gains in visual perceptual learning after sleep and increases in the excitatory-to-inhibitory neurotransmitter (E/I) ratio in early visual areas during sleep using magnetic resonance spectroscopy and polysomnography. These parameters were significantly smaller in sleep with the FNE than in sleep without the FNE; however, these parameters were not correlated with SOL. These results suggest that while the neural mechanisms of the FNE and brain plasticity are independent, sleep disturbances temporarily block the neurochemical process fundamental for brain plasticity.

First-night effect reduces the beneficial effects of sleep on visual plasticity and modifies the underlying neurochemical processes

Individuals experience difficulty falling asleep in a new environment, termed the first night effect (FNE). However, the impact of the FNE on sleep-induced brain plasticity remains unclear. Here, using a within-subject design, we found that the FNE significantly reduces visual plasticity during sleep in young adults. Sleep-onset latency (SOL), an indicator of the FNE, was significantly longer during the first sleep session than the second session, confirming the FNE. We assessed performance gains in visual perceptual learning after sleep and increases in the excitatory-to-inhibitory neurotransmitter (E/I) ratio in early visual areas during sleep using magnetic resonance spectroscopy and polysomnography. These parameters were significantly smaller in sleep with the FNE than in sleep without the FNE; however, these parameters were not correlated with SOL. These results suggest that while the neural mechanisms of the FNE and brain plasticity are independent, sleep disturbances temporarily block the neurochemical process fundamental for brain plasticity.

Primed Tactile Stimulus Processing during Sleep

The aim was to investigate how the primed and unprimed non-painful tactile stimuli during sleep would be processed. A total of 22 healthy subjects (19.55 ± 1.10 years) were randomly divided into two groups. The same stimuli were applied to both groups, but the study group (SG) received them twice (daytime and sleep), whereas the control group (CG) received them only during sleep. A 40-channel PSG and a pneumatic tactile stimulator unit were used. Evoked potential components of the CZ electrode were examined in four sleep stages (N1, N2, N3, and REM). The Mann-Whitney U test was used for group comparison, and the Wilcoxon test was used for in-group evaluations. The P50 and N300 response components were observed in all sleep stages in both groups. P50 decreased as sleep deepened in the SG. The N300 increased as sleep deepened and started to decrease again in the REM stage. Moreover, in N1, the amplitudes of P200-N300 and N300-P450 in the SG were significantly greater than those in the CG. The fact that P50 was observed even in N3 indicates that bottom-up sensory processing continues during sleep. Moreover, the central processing of primed and unprimed stimuli exhibited dynamic differences. Furthermore, an increase in N300 amplitude suggests suppressive processes to facilitate and maintain sleep.

Evaluation of the Accuracy of Contactless Consumer Sleep-Tracking Devices Application in Human Experiment: A Systematic Review and Meta-Analysis

Compared with the gold standard, polysomnography (PSG), and silver standard, actigraphy, contactless consumer sleep-tracking devices (CCSTDs) are more advantageous for implementing large-sample and long-period experiments in the field and out of the laboratory due to their low price, convenience, and unobtrusiveness. This review aimed to examine the effectiveness of CCSTDs application in human experiments. A systematic review and meta-analysis (PRISMA) of their performance in monitoring sleep parameters were conducted (PROSPERO: CRD42022342378). PubMed, EMBASE, Cochrane CENTRALE, and Web of Science were searched, and 26 articles were qualified for systematic review, of which 22 provided quantitative data for meta-analysis. The findings show that CCSTDs had a better accuracy in the experimental group of healthy participants who wore mattress-based devices with piezoelectric sensors. CCSTDs' performance in distinguishing waking from sleeping epochs is as good as that of actigraphy. Moreover, CCSTDs provide data on sleep stages that are not available when actigraphy is used. Therefore, CCSTDs could be an effective alternative tool to PSG and actigraphy in human experiments.