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Rocking synchronizes brain waves during a short nap

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Abstract

Why do we cradle babies or irresistibly fall asleep in a hammock? Although such simple behaviors are common across cultures and generations, the nature of the link between rocking and sleep is poorly understood [1 • Woodward S. • Tauber E.S. • Spielmann A.J. • Thorpy M.J. Effects of otolithic vestibular stimulation on sleep.Sleep. 1990; 13: 533-537 • PubMed • Google Scholar , 2 • Krystal A.D. • Zammit G.K. • Wyatt J.K. • Quan S.F. • Edinger J.D. • White D.P. • Chiacchierini R.P. • Malhotra A. The effect of vestibular stimulation in a four-hour sleep phase advance model of transient insomnia.J. Clin. Sleep Med. 2010; 6: 315-321 • PubMed • Google Scholar ]. Here we aimed to demonstrate that swinging can modulate physiological parameters of human sleep. To this end, we chose to study sleep during an afternoon nap using polysomnography and EEG spectral analyses. We show that lying on a slowly rocking bed (0.25 Hz) facilitates the transition from waking to sleep, and increases the duration of stage N2 sleep. Rocking also induces a sustained boosting of slow oscillations and spindle activity. It is proposed that sensory stimulation associated with a swinging motion exerts a synchronizing action in the brain that reinforces endogenous sleep rhythms. These results thus provide scientific support to the traditional belief that rocking can soothe our sleep.

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... Modulation of slow oscillations may affect sleep and post-sleep performance. Previous studies have used various slow rhythmic stimulations (< 1 Hz) to modulate sleep and sleep oscillations [22][23][24][25][26][27][28][29][30] , with effects including increased SWS, improved memory performance, enhanced slow oscillation activity, and entrainment of sleep oscillations. These stimulations are hypothesized to influence sleep oscillations via neural entrainment, a process whereby intrinsic neural oscillations in the brain synchronize with external and internal forces oscillating at certain frequencies 31 . ...
... The distinction between delta waves and slow oscillations at approximately 0.25 Hz may be even more pronounced than that between delta waves and slow oscillations at approximately 0.8 Hz, which overlap with the delta range and have been the focus of many studies. Few studies have specifically investigated the modulation of slow oscillations at approximately 0.25 Hz; nevertheless, existing research, including studies using rhythmic rocking, supports the effectiveness of this frequency in enhancing slow oscillations 22,23 and improving sleep. Sleep improvements include reduced N2 22,23 or N3 latency 25 and increased N2 23,26 , N3 22 , or combined N2 + N3 duration 24 . ...
... Few studies have specifically investigated the modulation of slow oscillations at approximately 0.25 Hz; nevertheless, existing research, including studies using rhythmic rocking, supports the effectiveness of this frequency in enhancing slow oscillations 22,23 and improving sleep. Sleep improvements include reduced N2 22,23 or N3 latency 25 and increased N2 23,26 , N3 22 , or combined N2 + N3 duration 24 . The underlying mechanism may involve neural entrainment of slow oscillations by 0.25-Hz stimulation 22 . ...
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Binaural beats can entrain neural oscillations and modulate behavioral states. However, the effect of binaural beats, particularly those with slow frequencies (< 1 Hz), on sleep remains poorly understood. We hypothesized that 0.25-Hz beats can entrain neural oscillations and enhance slow-wave sleep by shortening its latency or increasing its duration. To investigate this, we included 12 healthy participants (six women; mean age, 25.4 ± 2.6 years) who underwent four 90-min afternoon nap sessions, comprising a sham condition (without acoustic stimulation) and three binaural-beat conditions (0, 0.25, or 1 Hz) with a 250-Hz carrier tone. The acoustic stimuli, delivered through earphones, were sustained throughout the 90-min nap period. Both N2- and N3- latencies were shorter in the 0.25-Hz binaural beats condition than in the sham condition. We observed no significant results regarding neural entrainment at slow frequencies, such as 0.25 and 1 Hz, and the modulation of sleep oscillations, including delta and sigma activity, by binaural beats. In conclusion, this study demonstrated the potential of binaural beats at slow frequencies, specifically 0.25 Hz, for inducing slow-wave sleep in generally healthy populations.
... 42 can increase slow-wave spectral density. [43][44][45] As a result, it may enhance synchronous activity within thalamocortical networks, which in turn could promote sleep maintenance. 45 Our study found that the average power slow-wave (0.5-4 Hz) EEG spectral density in DYS patients was lower which is consistent with previous studies. ...
... [43][44][45] As a result, it may enhance synchronous activity within thalamocortical networks, which in turn could promote sleep maintenance. 45 Our study found that the average power slow-wave (0.5-4 Hz) EEG spectral density in DYS patients was lower which is consistent with previous studies. [43][44][45] This proves that patients without DYS have higher frequency slowwave oscillations and therefore have better deep sleep. ...
... 45 Our study found that the average power slow-wave (0.5-4 Hz) EEG spectral density in DYS patients was lower which is consistent with previous studies. [43][44][45] This proves that patients without DYS have higher frequency slowwave oscillations and therefore have better deep sleep. It was confirmed that patients with DYS have subjectively poor sleep quality in our previous study. ...
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Objective Levodopa‐induced dyskinesia (DYS) adversely affects the quality of life of Parkinson's disease (PD) patients. However, few studies have focused on the relationship between DYS and sleep and electroencephalography (EEG). Our study aimed to establish the objective physiological indicators assessed by polysomnography (PSG) that are associated with DYS in PD patients. Methods We enrolled 122 patients with PD, divided into two groups: PD with DYS (n = 27) and PD without DYS group (non‐DYS, n = 95). The demographics and clinical characteristics and sleep assessment in the two groups were collected. More importantly, overnight six‐channel PSG parameters were compared in the two groups. We also compared different bands and brain regions of average power spectral density within each group. Results Compared with the non‐DYS group, the DYS group tended to have a significantly higher percentage of nonrapid eye movement sleep (NREM). Gender, levodopa equivalent daily dose (LEDD), rapid eye movement (REM) sleep (min), and the NREM percentage were positively correlated with the occurrence of DYS. After adjusting for gender, disease duration, LEDD, taking amantadine or not, and Montreal Cognitive Assessment (MoCA), NREM%, N3%, and REM (min), the percentage of NREM sleep (p = 0.035), female (p = 0.002), and LEDD (p = 0.005), and REM sleep time (min) (p = 0.012) were still associated with DYS. There was no significant difference in whole‐night different bands of average power spectral density between two groups. There was no significant difference in normalized average power spectral density of slow wave activity (SWA) (0.5–2 Hz, 0.5–4 Hz, and 2–4 Hz) of early and late NREM sleep in the DYS group. Dynamic normalized average power spectral density of SWA of low‐frequency (0.5–2 Hz) reduction in the frontal region (p = 0.013) was associated with DYS in logistic regression after adjusting for confounding factors. Conclusion PD patients with DYS have substantial sleep structure variations. Higher NREM percentage and less REM percentage were observed in PD patients with DYS. Dynamic normalized average power spectral density of low‐frequency (0.5–2 Hz) SWA reduction in the frontal area could be a new electrophysiological marker of DYS in PD.
... Vestibular stimulation can be achieved by physically rocking the surface upon which someone sleeps at a constant frequency (Bayer et al., 2011), or by directly stimulating the vestibular nerves (transcutaneous vestibular nerve stimulation; Goothy & McKeown, 2020). Gentle rocking of the bed at 0.25 Hz during a nap increased SWA and spindle activity in healthy participants (Bayer et al., 2011). ...
... Vestibular stimulation can be achieved by physically rocking the surface upon which someone sleeps at a constant frequency (Bayer et al., 2011), or by directly stimulating the vestibular nerves (transcutaneous vestibular nerve stimulation; Goothy & McKeown, 2020). Gentle rocking of the bed at 0.25 Hz during a nap increased SWA and spindle activity in healthy participants (Bayer et al., 2011). In a follow-up study, rocking (0.25 Hz) during a full night of sleep significantly lengthened SWS duration and increased slow oscillations and spindle activity during SWS . ...
... In a follow-up study, rocking (0.25 Hz) during a full night of sleep significantly lengthened SWS duration and increased slow oscillations and spindle activity during SWS . While vestibular stimulation was effective in some studies in young human subjects (Bayer et al., 2011;Perrault et al., 2019), other studies in young and old humans (Omlin et al., 2018;Van Sluijs et al., 2020) and mice did not observe slow wave enhancement. Impairment of the peripheral vestibular system commonly found in older people (Ahearn & Umapathy, 2015) may result in limited effectiveness of this method. ...
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Sleep has been postulated to play an important role in the removal of potentially neurotoxic molecules, such as amyloid-β, from the brain via the glymphatic system. Disturbed sleep, on the other hand, may contribute to accumulation of neurotoxins in brain tissue, ultimately leading to neuronal death. A bidirectional relationship has been proposed between impaired sleep and neurodegenerative processes, which start years before the onset of clinical symptoms associated with conditions like Alzheimer’s and Parkinson’s disease. Given their heavy burden on society, it is imperative to develop interventions that promote efficient brain clearance and thereby could aid in preventing or slowing down neurodegeneration.In this review, we explore whether the metabolic clearance function of sleep can be enhanced through sensory (e.g., auditory, vestibular) or transcranial (e.g., magnetic, ultrasound, infra-red light) stimulation, as well as pharmacological (e.g., antiepileptics) and behavioral (e.g., sleeping position, physical exercise, cognitive intervention) modulation of sleep physiology. A particular focus will be placed on strategies to enhance slow-wave activity during non-rapid eye movement sleep as a driver of glymphatic brain clearance. Overall, the review provides a comprehensive overview on the potential preventative and therapeutic applications of sleep interventions in combating neurodegeneration, cognitive decline, and dementia.
... Bayer et al in his study including good sleepers with no sleep-disorders non-habitual showed that reclining on a gently oscillating bed at a frequency of 0.25 Hz aids in the shift from wakefulness to sleep and extends the duration of N2 sleep stages with an increased spindle density per an epoch of 30 seconds, with a shorter duration of stage N1, and of the latency to enter N2 [17]. ...
... This structure affects the sleeping processes, including sleep onset, depth, and the emotional effects related to sleep [18,19]. Most of the participants in the study of Bayer et al found a 'relaxing' feeling associated with the new sleeping environment and summarize the night as a pleasant experience [17]. Inputs of the vestibular or somatosensory systems given by the rocking movements may influence sleep control centres in hypothalamus or brainstem. ...
... Bayer et al. demonstrated that using a rocking bed not only shortens the onset of sleep but also increases the occurrence of two key sleep patterns observed through EEG: slow oscillations and sleep spindles. These two electrophysiological phenomena not only characterize NREM sleep but recent research has linked them to one of the most fascinating behavioural outcomes of sleep-memory consolidation [17]. Almost a hundred years ago, it was first shown that sleeping after learning enhances memory performance compared to being awake for the same duration. ...
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Sleep plays a crucial role in physical and mental well-being, being a fundamental component of the body's natural rehabilitation and recovery process. Adequate sleep not only facilitates tissue repair but also enhances cognitive function and mood. For those undergoing physical rehabilitation or recovering from injuries, prioritizing restorative sleep is indispensable, as it accelerates healing processes. Recent studies explore innovative technologies like rocking movements to enhance sleep quality. While anecdotal evidence suggests benefits, scientific literature on rocking movements remains limited. This narrative review examines the impact of rocking movements on sleep quality and memory processes. Studies suggest potential benefits, such as such as a shorter duration of N1, increased spindle density in the N2, and longer time spent in N3, indicating enhanced sleep quality. The potential relevance of these findings lies in advancing non-pharmacological treatments for individuals with insomnia or mood disorders, and they may also have implications for foraging populations dealing with reduced deep sleep and memory impairments. Further research in clinical settings is imperative to explore the impact of sleep quality on rehabilitation training, determining if the positive influences of sleep consolidation translate into substantial clinical outcomes in rehabilitative care.
... There is evidence that passive vestibular stimulation during sleep modulates respiration [9,10], sleep [11][12][13][14], and cognitive performance [12,13]. Recently, the influence of vestibular input on sleep architecture was also demonstrated in mice [15]. ...
... Given the evidence that passive vestibular stimulation can influence sleep [11,13,15], it is interesting to look at conditions under which vestibular cues are altered. In microgravity, which decreases vestibular input, astronauts' total sleep time is reduced [26]. ...
... However, no effects concerning the duration of sleep and sleep stages were found for the head-vertical translation condition as compared to the motionless conditions. Three decades later, Bayer et al. [11] revitalized rocking device research with their study testing human sleep on a rocking bed during a 45-min nap. They found that inter-aural translation led to faster sleep onset and longer N2 sleep, which was combined with higher sleep spindle density in N2 sleep. ...
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Rocking devices are widely used across different age groups to facilitate sleep. This review discusses the current literature on rocking devices and how passive vestibular stimulation influences sleep architecture, sleep oscillations, and cognitive performance. We included eight studies that conducted research with rocking devices in humans (7) and mice (1) during daytime naps and/or nighttime sleep, respectively. Overall, vestibular stimulation during sleep induced faster sleep onset, coupled with more N2 in daytime naps or N3 in nighttime sleep. Vestibular stimulation also led to more sleep spindles and better memory consolidation. Optimal stimulation intensity was around 25 cm/s2, and lower intensities led to smaller effects. The findings suggest a sweet spot for vestibular stimulation intensity, promoting deeper sleep at the cost of wakefulness or N1 sleep without compromising REM sleep. While further studies are needed to thoroughly investigate the motion parameters that drive the impact on sleep and cognitive performance, rocking devices may present a promising therapeutic tool for people with disrupted sleep patterns.
... Rocking is beneficial during a short nap [20], 66 ...
... Thelen (1980) suggests that vestibular stimulation deficiency may be one of the causes of persistent motor stereotypes in infants (persistent stereotypes, code F.98.4 in ICD-10) [18]. Bayer et al. (2011), investigated the relationship between rocking and sleeping [20]. The conclusions of their study indicated that lying on a slowly swaying bed (0.25 Hz) eases falling asleep and preferably extends the duration of the N2 sleep stage (one of three non-rapid eye movement (NREM) sleep phases before entering the REM period). ...
... Thelen (1980) suggests that vestibular stimulation deficiency may be one of the causes of persistent motor stereotypes in infants (persistent stereotypes, code F.98.4 in ICD-10) [18]. Bayer et al. (2011), investigated the relationship between rocking and sleeping [20]. The conclusions of their study indicated that lying on a slowly swaying bed (0.25 Hz) eases falling asleep and preferably extends the duration of the N2 sleep stage (one of three non-rapid eye movement (NREM) sleep phases before entering the REM period). ...
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Domestic cradles are beds that are movable but non-mobile for babies up to five months of age. The “anthropo-mechanical” cradle simulates the physiological movement of the human body. The article reviews scientific literature discussing the impacts of swinging on infants, provides classifications of all currently used cradles due to how the child moves, and briefly describes modern technologies within cradle automation. This made it possible to calculate and propose safe motion parameters within mechatronic cradles. The main conclusions of the article are as follows: (1) the scientific literature reports the beneficial effects of harmonic movement on a child, (2) motion analyses substantiating the classifications of all cradles into six types (tilting, yawing, hammock, Sarong, swing, and surging cradle; the classification criterion included the nature of the cradle movement in relation to the planes and anatomical axes of the child’s body), (3) modern technologies allowing for the use of movement with thoughtful parameters, thus, safer for a child, (4) movement within the parameters similar to the motion and speed passively performed by the child in the womb while a mother is walking was considered beneficial and safe, and (5) the use of advanced technology allows for the possibility to devise and create an automatic mechatronic cradle with a child-safe motion. Future innovative anthropo-mechanical cradles that follow physiological human motion parameters can be used safely, with a vertical amplitude ranging from −13 to + 15 mm and a frequency of up to 2 Hz.
... While effective in lab settings, its size made it impractical for home use. Similarly, Bayer and colleagues developed a parallel swing bed with metal bars, suspended from the ceiling, using a motor to create sinusoidal horizontal accelerations [5]. Despite finding that lateral rocking during afternoon naps increased spindle activity and slow oscillations in EEG recordings, indicating improved sleep quality and a smoother transition from wakefulness to deep sleep [5], their bed was also limited to laboratory environments, hindering long-term studies. ...
... Similarly, Bayer and colleagues developed a parallel swing bed with metal bars, suspended from the ceiling, using a motor to create sinusoidal horizontal accelerations [5]. Despite finding that lateral rocking during afternoon naps increased spindle activity and slow oscillations in EEG recordings, indicating improved sleep quality and a smoother transition from wakefulness to deep sleep [5], their bed was also limited to laboratory environments, hindering long-term studies. Shibagaki et al. recorded maternal rocking movements and designed a reclining chair to replicate these motions [6]. ...
Article
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Vestibular Stimulation (VS) has been shown to positively affect various autonomic body functions, including sleep. In the past, VS was often investigated using large and complex rocking beds that would only allow for short intervention periods in constrained lab settings. In this work, we present an overview of the mechanics, kinematics, dynamics, and tuning of our latest rocking bed, the Somnomat Casa. Its compact dimensions, comparable to a standard single bed, its connectivity, and easy usability, allow for prolonged studies in home settings investigating the effects of VS during sleep. In a first six-month study with a 12-year-old boy suffering from primary mitochondrial disease with an associated severe sleep disorder, we observed significant improvements in sleep duration (+25 %) and quality of life, as well as a 75 % reduction in caregiving interactions and a 40 % reduction in overall caregiving time. Based on these promising findings, we are currently testing the Somnomat Casa with various patient groups for multiple months each, including elderly with insomnia, children with sleep disorders, Parkinson’s disease patients, and individuals with post-stroke insomnia.
... Only a few studies have investigated the effects of vestibular stimulation on sleep. These studies have used vestibular stimulations induced by rocking movements or galvanic currents (i.e., a non-invasive method that stimulates the vestibular nerve using a direct low-intensity electrical current) (44)(45)(46). Polysomnography, a gold standard method (47), was used to record sleep in these studies. Research on rocking movements demonstrated improvements in sleep/wake transitions and alterations in electroencephalographic activity during nights or naps experienced on a moving bed compared to a stationary one (44,45). ...
... Polysomnography, a gold standard method (47), was used to record sleep in these studies. Research on rocking movements demonstrated improvements in sleep/wake transitions and alterations in electroencephalographic activity during nights or naps experienced on a moving bed compared to a stationary one (44,45). Only one study, employing a specific model involving an advance in bedtime by 4 h, has explored the effects of galvanic vestibular stimulation on sleep in a specific population (insomniacs), which revealed a reduction in persistent sleep latency (46). ...
Article
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Aging is characterized by substantial changes in sleep architecture that negatively impact fitness, quality of life, mood, and cognitive functioning. Older adults often fail to reach the recommended level of physical activity to prevent the age-related decline in sleep function, partly because of geographical barriers. Implementing home-based interventions could surmount these obstacles, thereby encouraging older adults to stay active, with videoconference administration emerging as a promising solution. Increasing the availability of biological rhythms synchronizers, such as physical activity, light exposure, or vestibular stimulation, represents a viable non-pharmacological strategy for entraining circadian rhythms and potentially fortifying the sleep–wake cycle, thereby enhancing sleep in aging. This study aims to (1) assess the impact of remote physical exercise training and its combination with bright light exposure, and (2) investigate the specific contribution of galvanic vestibular stimulation, to sleep quality among healthy older adults with sleep complaints. One hundred healthy older adults aged 60–70 years with sleep complaints will be randomly allocated to one of four groups: a physical exercise training group ( n = 25), a physical exercise training combined with bright light exposure group ( n = 25), a galvanic vestibular stimulation group ( n = 25) or a control group (i.e., health education) ( n = 25). While physical exercise training and health education will be supervised via videoconference at home, bright light exposure (for the physical exercise training combined with bright light exposure group) and vestibular stimulation will be self-administered at home. Pre-and post-tests will be conducted to evaluate various parameters, including sleep (polysomnography, subjective questionnaires), circadian rhythms (actigraphy, temperature), fitness (physical: VO 2 peak, muscular function; and motor: balance, and functional mobility), cognition (executive function, long-term memory), quality of life and mood (anxiety and depression). The findings will be anticipated to inform the development of recommendations and non-pharmaceutical preventive strategies for enhancing sleep quality in older adults, potentially leading to improvements in fitness, cognition, quality of life, and mood throughout aging.
... Gentle rocking motions as a form of vestibular stimulation have emerged as a promising non-pharmacological option [14,15]. The utilization of vestibular stimulation has been explored as a soothing and calming intervention in the context of treating diverse psychiatric and neurological conditions [16]. ...
... The study by Bayer et al. including 12 male patients, focusing on the effects of reclining on a gently oscillating bed, parallels our findings of a facilitated transition from wakefulness to sleep, prolonged duration of N2 sleep stages, and an increased spindle density (p < 0.001). These similarities further strengthen the evidence suggesting a favourable impact of rocking beds on sleep architecture [14]. ...
Article
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Introduction: Achieving restorative sleep is crucial for overall well-being, yet sleep difficulties affect a substantial portion of the adult population. Sleep disturbances are associated with diminished quality of life, physical complaints, cognitive impairment, and emotional regulation challenges. Objective: This study explores the influence of an innovative experimental bed designed to generate rocking motions on sleep parameters. Methods: A prospective observational study enrolled 60 adult participants, assessing their sleep on a regular stationary bed and the Inoveris bed, providing gentle rocking movements. Polysomnography was conducted, recording electroencephalography, electrooculogram, electromyogram, respiratory effort, and other parameters. Results: The rocking bed significantly increased total sleep time (TST) and reduced N1 sleep stage duration (p < 0.001). Participants also experienced a quicker transition to the N2 sleep stage (p = 0.01), indicative of a faster shift from wakefulness to deeper sleep. Additionally, rocking led to a higher percentage of N1 sleep stages (p = 0.01) and a significant increase in N3 sleep stage duration (p = 0.004). While some results lacked statistical significance, notable trends in the rocking bed group have clinical relevance, consistently improving sleep parameters, including increased TST. The rocking bed also showed a trend towards higher sleep efficiency (SE) and sleep duration percentage, hinting at a potential overall enhancement in sleep quality. Conclusion: This study contributes valuable insights into the potential benefits of rocking motions on sleep architecture. Despite variations in outcomes across studies, our results underscore the potential of rocking beds as a non-pharmacological intervention for enhancing sleep quality. Notable improvements in total sleep time (TST), N1 sleep stage reduction, and accelerated transitions to deeper sleep stages highlight the clinical relevance of rocking interventions. Further research, collaboration, and addressing the identified limitations will advance our understanding of the therapeutic applications of rocking motions in sleep science.
... Only few studies evaluated the effects of vestibular stimulation on sleep. Vestibular stimulations were induced by rocking movements or by galvanic currents (i.e. a non-invasive method used to stimulate the vestibular nerve with a direct low intensity electrical current) (41)(42)(43). These studies used polysomnography, a gold standard for recording sleep (44). ...
... These studies used polysomnography, a gold standard for recording sleep (44). The rocking movements showed an improvement in sleep/wake transitions and a change in electroencephalographic activity during a night or a nap experienced using moving bed compared to a stationary bed (41,42). Only one study explored the effects of galvanic vestibular stimulation on sleep in a speci c population (insomniacs) in a speci c model of phase advance (4-hours bedtime advanced; (43)). ...
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Background: Aging is characterized by substantial changes in sleep architecture that negatively impact physical fitness, quality of life, mood or cognitive functioning. Older adults often fail to reach the recommended amount of physical activity to prevent the age-related decline sleep function, partly because of geographical barriers. Home-based interventions could overcome these barriers preventing older adults from being active, and administration through videoconference may be an optimal solution. Increasing the availability of synchronisers such as physical activity, light exposure or vestibular stimulation is a good non-pharmacological strategy for circadian rhythms entrainment and could strengthen the sleep-wake cycle and thus improve sleep in the ageing subject. The aims of this study are (1) to evaluate the effects of a remote physical exercise training and a remote physical exercise training combined with bright light exposure, and (2) to study the specific contribution of galvanic vestibular stimulation on sleep in healthy older adults with sleep complaint. Methods: One hundred healthy older adults (60-70 years old) with sleep complaint will be randomized to a physical exercise training group (n=25), a physical exercise training combined with bright light exposure group (n=25), a galvanic vestibular stimulation group (n=25) or a control group (i.e. health education) (n=25). While physical exercise training and health education will be supervised by videoconference at home, bright light exposure (from the physical exercise training combined with bright light exposure group) and vestibular stimulation will be self-administered at home. Pre- and post- tests will be performed to assess: sleep (polysomnography, subjective questionnaires), circadian rhythms (actigraphy, temperature), physical fitness (VO2peak, muscular function, postural control and functional mobility), cognition (executive function, long-term memory), quality of life and mood (anxiety and depression). Discussion: The results should support the development of recommendations and non-pharmaceutical preventive strategies to maintain or even improve sleep quality in older adults and, consequently, to improve physical fitness, cognition, quality of life and mood throughout aging. Trial registration: Clinicaltrials.gov ID: NCT05030389. Registered on September - retrospectively registered.
... In mice, rocking improved going to sleep and increased the quantity of slowwave sleep, this effect being mediated by the reaction of the vestibular system to acceleration [Kompotis et al., 2019]. Despite these studies, the exact mechanisms of the relaxing effect of rocking remain unclear although, perhaps, the mechanism consists of synchronization of the thalamocortical networks with vestibular signals, as in the case of other sensory treatments [Bayer et al., 2011;Perrault et al., 2019]. ...
... The positive infl uences of rocking on sleep in adult subjects have been demonstrated in several experiments. During daytime sleep, rocking at 0.25 Hz accelerated falling asleep and increased the proportion of the second stage of sleep, increasing the number of sleep spindles and SA in the second half of sleep [Bayer et al., 2011]. Acceleration of falling asleep with rocking at 0.24-0.3 ...
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Sleep is needed for maintenance of normal homeostasis and memory consolidation processes and the deep third stage of sleep plays a particularly important role. However, a significant proportion of the population suffers from poor sleep quality, insomnia, and problems with going to sleep. Pharmacological treatment of these problems is not always possible or appropriate, and in recent years we have seen increasing interest in nonpharmacological methods of influencing falling asleep and sleep. This review addresses various approaches to improving sleep quality and accelerating going to sleep: sensory actions of different modalities, approaches using transcranial stimulation, and normalization of daily sleep–waking rhythms. This article considers their main possible mechanisms of action. Nonpharmacological treatments most commonly produce increases in slow-wave activity in the third stage of sleep. The areas of application of different approaches are assessed: from exclusively research purposes to application in clinical practice and use in consumer devices.
... For countless centuries, rocking has been used to promote sleep and relaxation in infants [13]. Rocking also influences sleep among adults by promoting relaxation [14]. It is considered to reduce psychological tension, as similar effects have been observed after Healthcare 2022, 10, 2337 2 of 12 performing similar activities involving swaying or oscillatory motion. ...
... Although previous works have suggested that swaying promotes relaxation and sleep in infants [13] and affects adult sleep while promoting relaxation effects [14], only a few studies have investigated the impact of sway stimuli applied by sway beds on children with SMID. However, as reported in previous studies [15][16][17][18], applying a sway stimulus to children with SMID through the introduction of sway beds in schools, in the context of rehabilitation, or as part of leisure activities may result in a daily relaxation effect on children with SMID. ...
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This cross-sectional study aimed to examine the effects of being swayed in a sway bed on children with severe motor and intellectual difficulties by examining potential differences in their autonomic and emotional responses, as well as their muscle hardness, and by comparing them with “a control condition without any stimulation”. Children’s heart rate variability, rectus femoris hardness, and passive hip abduction range of motion (ROM) were measured in two experimental conditions, differentiated by the presence of a 5-min sway stimulus. In each condition, the children’s faces were video-recorded and retrospectively rated subjectively by their homeroom teacher concerning the visible expression of eight emotions. Significant intervention-related effects were observed on the heart rate variability and the “Relax” item of the emotional response indicators but not on muscle hardness or hip ROM. Our findings provide evidence that using a motorized sway bed can promote relaxation in children with severe motor and intellectual disabilities by influencing their autonomic response.
... It has also been found that a continuous rocking motion can provide sleep benefits. In one study, participants took 45-minute naps and it was shown that rocking reduced sleep latency and enhanced sleep by boosting slow oscillations and spindle activity [20]. In another study in which participants were continuously rocked during the entire night, it was found that sleep latency was reduced, and a deeper sleep with fewer arousals was achieved [21]. ...
... Therefore, it was decided to use standing wave and beat frequency combinations near 27 Hz. Literature has shown that oscillations of 2 Hz and lower are generally most effective at inducing/improving sleep [16], [18], [19], [20], [21], [22]. Therefore, it was desired to select a beat frequency somewhere in this range for clinical testing. ...
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Insomnia affects millions of people A bed excited with multiple vibration sources was used to explore beat frequency vibration (BFV) as a non-pharmacological treatment for insomnia. A repeated measures design pilot study of 14 participants with mild-moderate insomnia symptom severity (self-reported on the Insomnia Severity Index) was conducted to determine the effects of BFV, and traditional standing wave vibration (SWV) on sleep latency and sleep electrocortical activity. Participants were monitored using high-density electroencephalography (HD-EEG). Sleep latency was compared between treatment conditions. A trend of decreasing sleep latency due to BFV was found for unequivocal sleep latency (p ≤ 0.068). Neural complexity during wake, N1, and N2 stages were compared using Multi-Scale Sample Entropy (MSE), which demonstrated significantly lower MSE between wake and N2 stages (p ≤ 0.002). During N2 sleep, BFV showed lower MSE than the control session in the left frontoparietal region. As a measure of information integration, reduced entropy may indicate that BFV decreases conscious awareness during deeper stages of sleep. SWV caused reduced alpha activity and increased delta activity during wake. BFV caused increased delta activity during N2 sleep. These preliminary results suggest that BFV may help decrease sleep latency, reduce conscious awareness, and increase sleep drive expression during deeper stages of sleep. SWV may be beneficial for decreasing expression of arousal and increasing expression of sleep drive during wake, implying that beat frequency vibration may be beneficial to sleep.
... One such approach is vestibular stimulation, which involves the gentle rocking of vibrational movements. Bayer et al. (2011) used a continuous rocking stimulation (0.25 Hz) with a bed equipped with an electrical rotor to produce vibrational excursions in 12 good sleepers during naps. The results showed reduced sleep latency, increased non-rapid eye movement (non-REM) sleep, and enhanced sleep spindles. ...
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Introduction Recent studies have investigated the autonomic modulation method using closed-loop vibration stimulation (CLVS) as a novel strategy for enhancing sleep quality. This study aimed to explore the effects of CLVS on sleep quality, autonomic regulation, and brain activity in individuals with poor sleep quality. Methods Twenty-seven participants with poor sleep quality (Pittsburgh sleep quality index >5) underwent two experimental sessions using polysomnography and a questionnaire, one with CLVS (STIM) and the other without (SHAM). Results Sleep macrostructure analysis first showed that CLVS significantly reduced the total time, proportion, and average duration of waking after sleep onset. These beneficial effects were paralleled by significantly increased self-reported sleep quality. Moreover, there was a significant increase in the normalized high-frequency (nHF) and electroencephalography relative powers of delta activity during N3 sleep under STIM. Additionally, coherence analysis between nHF and delta activity revealed strengthened coupling between cortical and cardiac oscillations. Discussion This study demonstrated that CLVS significantly improves sleep quality in individuals with poor sleep quality by enhancing both subjective and objective measures. These findings suggest that CLVS has the potential to be a practical, noninvasive tool for enhancing sleep quality in individuals with sleep disturbances, offering an effective alternative to pharmacological treatments.
... frontiersin.org Authors concluded that "rocking induces a speeded transition to an unambiguous sleep state and may enhance sleep by boosting slow oscillations and spindle activity" (Bayer et al., 2011). More recently, it was found that compared to a stationary night, continuous rocking (at 0.25 Hz) shortened the latency to non-REM (NREM) sleep and strengthened sleep maintenance by increasing the duration of NREM stage 3 (N3) and fewer arousals. ...
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This work discusses the challenges of space exploration, focusing on microgravityinduced physiological changes, particularly those affecting the vestibular system, which significantly alters human performance in space, necessitating effective countermeasures. In microgravity, astronauts experience disorientation and space motion sickness due to changes in vestibular input, leading to symptoms like vertigo and headache. Postflight, astronauts show various neurological changes, similar to symptoms in individuals with vestibular disorders experiencing significant cognitive and perceptual difficulties. Studies have also shown that microgravity affects cortical and sensory responses, altering perception, motor function, and brain connectivity. Galvanic Vestibular Stimulation (GVS) is explored as a countermeasure, using modulated electrical currents to evoke neuronal activity in vestibular end-organs, potentially stabilizing posture and gaze in microgravity. The work proposes that GVS could serve as a non-invasive intervention to help adapt to space environments by enhancing vestibular function and possibly aiding cognitive functions and underscores the need for continued research into the vestibular system’s role in human health and performance during space missions. It highlights the potential of GVS as a promising countermeasure for the challenges posed by microgravity.
... First, physiological evidence supports these links: (a) the vestibular system can impact rapid eye movements (REM) during sleep [16][17][18][19]; (b) vestibular inputs to neurons in the pontine reticular formation play a role in mediating transitions between sleep states [15,20,21]; and (c) the medial vestibular nucleus projects to cortical regions involved in arousal and certain aspects of sleep, receiving orexinergic inputs from the lateral hypothalamus [15]. Second, human studies have shown that vestibular stimulation by rocking can accelerate the transition between wakefulness and sleep and enhance sleep quality during napping [22,23]. Stimulation of the otoliths via linear bed movements has shown potential effects on drowsiness [24,25]. ...
... Vestibular stimulation was among the first techniques explored for its potential to induce sleep, likely due to the traditional belief that physical rocking aids in sleep induction, as seen in babies or hammock swinging. Research findings from studies in both humans and rodents have demonstrated that rocking not only facilitates sleep onset but also increases the duration of NREM sleep without impacting REM sleep [18][19][20]. ...
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Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with cognitive decline and characterized by beta-amyloid plaque and tau tangle pathology. Recent research indicates a bidirectional relationship between AD pathology and sleep disturbances, with disrupted sleep exacerbating AD progression through increased beta-amyloid and tau accumulation. This strongly indicates that improving sleep may exert a direct protective effect on preventing the accumulation and spreading of AD pathology, and possibly slow the cognitive decline. Here we investigated the effects of enhancing sleep via vestibular stimulation (rocking) on AD progression in a 3xTg mouse model. Over a four-month period starting in early adulthood (p60), we monitored sleep patterns, motor function, memory, and AD pathology. Twelve-hour rocking during the light period significantly increased non-rapid eye movement (NREM) sleep duration in mice, although this effect diminished over time due to habituation. Despite this, rocking attenuated motor function decline and reduced beta-amyloid levels in the cerebral cortex of treated mice. No noticeable changes in tau levels were observed following sleep enhancement. In conclusion, our findings highlight the potential of non-pharmacological methods to enhance NREM sleep and modify disease trajectory in AD models, emphasizing the critical role of sleep in neuroprotection.
... Sleep is a complex process regulated by many factors, including sensory input. 1 Anecdotal observations have long suggested the soothing effect of gentle rocking on infants, leading to experimental studies confirming its sleep-promoting effects in both infants and adults as well as mice. [2][3][4][5] Furthermore, rocking-induced sleep has been shown to enhance memory in adult humans. 6 We and others have recently reported that gentle mechanical stimulation induces sleep in Drosophila as well. ...
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Study Objectives: Sleep is a complex phenomenon regulated by various factors, including sensory input. Anecdotal observations have suggested that gentle rocking helps babies fall asleep, and experimental studies have verified that rocking promotes sleep in both humans and mice. Recent studies have expanded this understanding, demonstrating that gentle vibration also induces sleep in Drosophila. Natural sleep serves multiple functions, including learning and memory, synaptic downscaling, and clearance of harmful substances associated with neurodegenerative diseases. Here, we investigated whether vibration-induced sleep provides similar cognitive and health benefits in Drosophila. Methods: We administered gentle vibration to flies that slept very little due to a forced activation of wake-promoting neurons and investigated how the vibration influenced learning and memory in the courtship conditioning paradigm. Additionally, we examined the effects of VIS on synaptic downscaling by counting synapse numbers of select neurons. Finally, we determined whether vibration could induce sleep in Drosophila models of Alzheimer's disease (AD) and promote the clearance of Amyloid β (Aβ) and Tubulin Associated Unit (TAU). Results: Vibration-induced sleep enhanced performance in a courtship conditioning paradigm and reduced the number of synapses in select neurons. Moreover, vibration improved sleep in Drosophila models of AD, promoting the clearance of Aβ and TAU. Conclusions: Mechanosensory stimulation offers a promising non-invasive avenue for enhancing sleep, potentially providing associated cognitive and health benefits.
... Vestibular stimulation (VS) could be a promising additional option to classical pharmaceutical treatments (e.g. dopamine agonists, benzodiazepines or melatonin) as it is known to have positive effects on respiration, heart rate and blood pressure (Monahan & Ray, 2002;Omlin et al., 2016;Thurrell et al., 2003), on sleep consolidation and sleep onset (Bayer et al., 2011;van Sluijs et al., 2020;Woodward & Tauber, 1990), on psychological (Cross et al., 2018;Sailesh et al., 2014), neurological (Dave, 1992), neurodevelopmental (Ottenbacher et al., 1981) and neurodegenerative disorders, and on Parkinson's disease (Grabherr et al., 2015;Khoshnam et al., 2018;Wilkinson et al., 2019). However, to our knowledge, nocturnal VS has never been investigated in patients suffering from MD. ...
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Mitochondrial diseases are rare genetic disorders often accompanied by severe sleep disorders. We present the case of a 12-year-old boy diagnosed with a severe primary mitochondrial disease, exhibiting ataxia, spasticity, progressive external ophthalmoplegia, cardiomyopathy and severely disrupted sleep, but no cognitive impairment. Interestingly, his parents reported improved sleep during night train rides. Based on this observation, we installed a rocking bed in the patient's bedroom and performed different interventions, including immersive multimodal vestibular, kinesthetic and auditory stimuli, reminiscent of the sensory experiences encountered during train rides. Over a 5-month period, we conducted four 2-week nocturnal interventions, separated by 1-week washout phases, to determine the subjectively best-perceived stimulation parameters, followed by a final 4-week intervention using the optimal parameters. We assessed sleep duration and quality using the Mini Sleep Questionnaire, monitored pulse rate changes and used videography to document nocturnal interactions between the patient and caregivers. Patient-reported outcome measures, clinical examinations and personal outcomes of specific interests were used to document daytime sleepiness, restlessness, anxiety, fatigue, cognitive performance and physical posture. In the final 4-week intervention, sleep duration increased by 25%, required caregiver interactions reduced by 75%, and caregiving time decreased by 40%. Subjective fatigue, assessed by the Checklist Individual Strength, decreased by 40%, falling below the threshold of severe fatigue. Our study suggests that rocking beds could provide a promising treatment regime for selected patients with persistent severe sleep disorders. Further research is required to validate these findings in larger patient populations with sleep disorders and other conditions.
... Ornitz et al. [34] investigated bed rocking in 8 young children and found significant increases in both REM density and percentage of REM sleep time compared to sleeping in a stationary bed. Woodward et al. [35] studied vestibular stimulation's effects on adults' sleep in an elaborate 6-night and 2-day study that involved two adaptation nights, 2-bed rocking conditions, 2-stationary nights, and 2-Multiple Sleep Latency Tests (MSLT). She found a decrease in stage 2 sleep and increased REM density on the rocking compared to the stationary nights. ...
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Purpose of Review The vestibular system plays a role in both sleep and circadian rhythm regulation. Therefore, it has become a target for those interested in improving sleep quality. The purpose of this paper is to review the work that has been done in the area. Recent Findings The results of studies investigating the effects of vestibular stimulation on improving sleep quality have been mixed. However, double-blind, randomized controlled trials with diverse participant populations suffering from insomnia are lacking. Nonetheless, improved respiratory function with bed rocking has been seen, which can improve sleep quality in cases of sleep fragmentation due to hypoventilation. Summary Despite growing interest in improving sleep quality with vestibular stimulation in sleep, modest evidence exists of the effectiveness of this method in those with normal respiratory function.
... Participants were taught to perform the rehabilitation program for 30 min four times a day over five days when they were in the hospital, and this program was conducted in groups. Similarly, compared to a stationary condition, continuous rocking (at 0.25 Hz) during an afternoon nap or the night promoted sleep by reducing latency into and maintenance of deep sleep (non-REM) in healthy volunteers [108,109]. Finally, a study evaluating the effects of a recliner chair with a rocking motion on sleep in healthy volunteers reported a decrease in light sleep and an increase in deep sleep when the chair moved compared to being stationary [110]. ...
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Insomnia symptoms are common among patients with breast cancer (BC; 20–70%) and are predictors of cancer progression and quality of life. Studies have highlighted sleep structure modifications, including increased awakenings and reduced sleep efficiency and total sleep time. Such modifications may result from circadian rhythm alterations consistently reported in this pathology and known as carcinogenic factors, including lower melatonin levels, a flattened diurnal cortisol pattern, and lower rest-activity rhythm amplitude and robustness. Cognitive behavioral therapy and physical activity are the most commonly used non-pharmacological interventions to counter insomnia difficulties in patients with BC. However, their effects on sleep structure remain unclear. Moreover, such approaches may be difficult to implement shortly after chemotherapy. Innovatively, vestibular stimulation would be particularly suited to tackling insomnia symptoms. Indeed, recent reports have shown that vestibular stimulation could resynchronize circadian rhythms and improve deep sleep in healthy volunteers. Moreover, vestibular dysfunction has been reported following chemotherapy. This perspective paper aims to support the evidence of using galvanic vestibular stimulation to resynchronize circadian rhythms and reduce insomnia symptoms in patients with BC, with beneficial effects on quality of life and, potentially, survival.
... However, the lack of an unambiguous candidate region as well as the ethical constraints related to the small but serious risk of surgical complications make it unlikely that DBS will soon be used in the treatment of insomnia.Transcutaneous vestibular nerve stimulation (VeNS) and bed rocking are two methods to stimulate the vestibular apparatus, which is the motion-sensing structure located in the inner ear(Figure 3b). Some evidence suggests that stimulating the vestibular system using rocking movements can affect sleep architecture, brain oscillations and sleeprelated memory consolidation both in animals and in healthy human participants(Bayer et al., 2011;Kompotis et al., 2019). However, conflicting results have been reported regarding the effectiveness of this technique in modulating sleep(Omlin et al., 2018;van Sluijs et al., 2020). ...
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Despite the success of cognitive behavioural therapy for insomnia and recent advances in pharmacotherapy, many patients with insomnia do not sufficiently respond to available treatments. This systematic review aims to present the state of science regarding the use of brain stimulation approaches in treating insomnia. To this end, we searched MEDLINE, Embase and PsycINFO from inception to 24 March 2023. We evaluated studies that compared conditions of active stimulation with a control condition or group. Outcome measures included standardized insomnia questionnaires and/or polysomnography in adults with a clinical diagnosis of insomnia. Our search identified 17 controlled trials that met inclusion criteria, and assessed a total of 967 participants using repetitive transcranial magnetic stimulation, transcranial electric stimulation, transcutaneous auricular vagus nerve stimulation or forehead cooling. No trials using other techniques such as deep brain stimulation, vestibular stimulation or auditory stimulation met the inclusion criteria. While several studies report improvements of subjective and objective sleep parameters for different repetitive transcranial magnetic stimulation and transcranial electric stimulation protocols, important methodological limitations and risk of bias limit their interpretability. A forehead cooling study found no significant group differences in the primary endpoints, but better sleep initiation in the active condition. Two transcutaneous auricular vagus nerve stimulation trials found no superiority of active stimulation for most outcome measures. Although modulating sleep through brain stimulation appears feasible, gaps in the prevailing models of sleep physiology and insomnia pathophysiology remain to be filled. Optimized stimulation protocols and proof of superiority over reliable sham conditions are indispensable before brain stimulation becomes a viable treatment option for insomnia.
... Augmentation of memory consolidation during sleep has previously been explored using pharmacological methods [39,40], auditory stimulation [41], Targeted Memory Reactivation (TMR; [42][43][44][45]), and even by physically rocking participants during sleep [46]. The use of tDCS or tACS during sleep has been shown to improve memory performance in various ways, including recall [6,47] and encoding [48]. ...
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Previous studies have found a benefit of closed-loop transcranial alternating current stimulation (CL-tACS) matched to ongoing slow-wave oscillations (SWO) during sleep on memory consolidation for words in a paired associates task (PAT). Here, we examined the effects of CL-tACS in a retroactive interference PAT (ri-PAT) paradigm, where additional stimuli were presented to increase interference and reduce memory performance. Thirty-one participants were tested on a PAT before sleep, and CL-tACS was applied over the right and left DLPFC (F3 and F4) vs. mastoids for five cycles after detection of the onset of each discrete event of SWO during sleep. Participants were awoken the following morning, learned a new PAT list, and then were tested on the original list. There was a significant effect of stimulation condition (p = 0.04297; Cohen’s d = 0.768), where verum stimulation resulted in reduced retroactive interference compared with sham and a significant interaction of encoding strength and stimulation condition (p = 0.03591). Planned simple effects testing within levels of encoding revealed a significant effect of stimulation only for low-encoders (p = 0.0066; Cohen’s d = 1.075) but not high-encoders. We demonstrate here for the first time that CL-tACS during sleep can enhance the protective benefits on retroactive interference in participants who have lower encoding aptitude.
... The impact of optimally designed playgrounds may yield additional benefits for motor skill development [26], balance, and proprioception [27,28]. For instance, swings have been linked to better sleep [29]. Climbers can help people become more agile and flexible in their movements. ...
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Background: The study goal was to identify playground features associated with visitor length of stay and physical activity. Methods: We observed playground visitors over 4 days during summer 2021 in 60 playgrounds in 10 US cities, selected based on design, population density, and poverty levels. We observed 4278 visitors and documented their length of stay. We observed an additional 3713 visitors for 8 min, recording their playground location, activity level, and use of electronic media. Results: People stayed an average of 32 min (range 5 min-4 h). Stay time varied by group size, with larger groups staying longer. The presence of restrooms increased the likelihood of staying longer by 48%. Playground size, mature trees, swings, climbers, and spinners were associated with longer stays. When a teen was a part of the group observed, the group was 64% less likely to stay longer. The use of electronic media was associated with lower amounts of moderate-to-vigorous physical activity compared to non-media users. Conclusions: To increase population-level physical activity and time spent outdoors, playground features associated with a longer stay should be considered when renovating or building new playgrounds.
... A more recent study which focused on the intrinsic properties of sleep found that natural vestibular stimulation speeds up transition from wake to sleep and increases sleep stage N2 in daytime naps (Bayer et al., 2011). Vestibular stimulation was obtained using a bed that swung with a moderate to low frequency of 0.25 Hz and a peak horizontal acceleration of 0.1 m/s 2 . ...
... First, we noted (without a hypothesis beforehand) that all the group results of the BF, PRV, and HRV spectra showed this peak frequency band. Second, previous studies have shown that stimulation around 0.25 Hz promotes sleep (Bayer et al., 2011;Perrault et al., 2019;van Sluijs et al., 2020). Third, the effects of respiration around 0.2-0.3 ...
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Pulse rate variability (PRV), derived from Laser Doppler flowmetry (LDF) or photoplethysmography, has recently become widely used for sleep state assessment, although it cannot identify all the sleep stages. Peripheral blood flow (BF), also estimated by LDF, may be modulated by sleep stages; however, few studies have explored its potential for assessing sleep state. Thus, we aimed to investigate whether peripheral BF could provide information about sleep stages, and thus improve sleep state assessment. We performed electrocardiography and simultaneously recorded BF signals by LDF from the right-index finger and ear concha of 45 healthy participants (13 women; mean age, 22.5 ± 3.4 years) during one night of polysomnographic recording. Time- and frequency-domain parameters of peripheral BF, and time-domain, frequency-domain, and non-linear indices of PRV and heart rate variability (HRV) were calculated. Finger-BF parameters in the time and frequency domains provided information about different sleep stages, some of which (such as the difference between N1 and rapid eye movement sleep) were not revealed by finger-PRV. In addition, finger-PRV patterns and HRV patterns were similar for most parameters. Further, both finger- and ear-BF results showed 0.2–0.3 Hz oscillations that varied with sleep stages, with a significant increase in N3, suggesting a modulation of respiration within this frequency band. These results showed that peripheral BF could provide information for different sleep stages, some of which was complementary to the information provided by PRV. Furthermore, the combination of peripheral BF and PRV may be more advantageous than HRV alone in assessing sleep states and related autonomic nervous activity.
... Although information processing during sleep is not limited to the auditory pathway, studies focusing on modalities other than the acoustic are scarce. Previous studies indicate that rhythmic vestibular stimulation may also increase slow frequency activity and deepen sleep during a daytime nap (Bayer et al., 2011). On the other hand, repetitive visual stimulation was not effective to enhance slow wave activity in contrast to acoustic stimulation of similar rhythmicity (Danilenko et al., 2020). ...
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Slow frequency activity during non-rapid eye movement (NREM) sleep emerges from synchronized activity of widely distributed thalamo-cortical and cortico-cortical networks, reflecting homeostatic and restorative properties of sleep. Slow frequency activity exhibits a reactive nature, and can be increased by acoustic stimulation. Although non-invasive brain stimulation is a promising technique in basic and clinical sleep research, sensory stimulation studies focusing on modalities other than the acoustic are scarce. We explored here the potential of lateralized vibro-tactile stimulation (VTS) of the finger to locally modify electroencephalographic activity during nocturnal NREM sleep. Eight seconds-long sequences of vibro-tactile pulses were delivered at a rate of 1 Hz either to the left or to the right index finger, in addition to a sham condition, in fourteen healthy participants. VTS markedly increased slow frequency activity that peaked between 1–4 Hz but extended to higher (~13 Hz) frequencies, with fronto-central dominance. Enhanced slow frequency activity was accompanied by increased (14–22 Hz) fast frequency power peaking over central and posterior locations. VTS increased the amplitude of slow waves, especially during the first 3–4 s of stimulation. Noticeably, we did not observe local-hemispheric effects, that is, VTS resulted in a global cortical response regardless of stimulation laterality. VTS moderately increased slow and fast frequency activities in resting wakefulness, to a much lower extent compared to NREM sleep. The concomitant increase in slow and fast frequency activities in response to VTS indicates an instant homeostatic response coupled with wake-like, high-frequency activity potentially reflecting transient periods of increased environmental processing. © 2022 The Authors. Psychophysiology published by Wiley Periodicals LLC on behalf of Society for Psychophysiological Research.
... Although the idea of trying to get a baby to sleep by gentle rocking seems natural to anyone who has been around infants, this is less easily achieved for adults. Despite this, there appears to be some supporting research for vestibular stimulation or physical rocking enhancing sleep both in children and in adults (e.g., Bayer et al., 2011;Cordero et al., 1986;Krystal et al., 2010;Perrault et al., 2019;Woodward et al., 1990). The mechanisms behind these effects however are not entirely clear and teasing out what aspect of rocking is vital in a complex sensory stimulation setup is not easy. ...
Chapter
Sleep is essential for optimal health, well-being and performance, with NREM and REM sleep each playing a role in maintaining optimal brain states. Slow wave sleep (SWS) is the deepest and most restorative stage of NREM sleep and is critical for cognitive function and aspects of brain and physical health. Advancing age, some psychiatric conditions, and challenging/diminished sleep opportunities lead to a reduction of SWS levels. Recent technologies have thus been developed to restore or enhance SWS using non-invasive brain stimulation techniques. This article explores the use of these technologies in enhancing SWS, and the potential benefit on physiological and psychological functioning, across different populations. Although other aspects of sleep remain important for optimal function (e.g., REM sleep), technologies focused on these aspects of sleep are fewer and in their infancy. While current technological approaches to enhancing sleep are promising, more research is needed to understand their long-term effects and potential benefits.
... The maximal linear acceleration applied was a more important variable than the rocking rate per se. In human studies, lying in a rocking bed (0.25 Hz) during a short nap (Bayer et al., 2011) or over the whole night accelerated sleep onset, entrained NREM sleep oscillations (0.5-5 Hz slow wave activity and sleep spindles) and enhanced sleep-dependent memory consolidation, an effect correlated with the increase in fast sleep spindles . Thus, rocking may be an effective way to promote sleep and NREM sleep oscillations which are important for sleep-dependent memory formation. ...
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Sleep disorders are widespread in society and are prevalent in military personnel and in Veterans. Disturbances of sleep and arousal mechanisms are common in neuropsychiatric disorders such as schizophrenia, post-traumatic stress disorder, anxiety and affective disorders, traumatic brain injury, dementia, and substance use disorders. Sleep disturbances exacerbate suicidal ideation, a major concern for Veterans and in the general population. These disturbances impair quality of life, affect interpersonal relationships, reduce work productivity, exacerbate clinical features of other disorders, and impair recovery. Thus, approaches to improve sleep and modulate arousal are needed. Basic science research on the brain circuitry controlling sleep and arousal led to the recent approval of new drugs targeting the orexin/hypocretin and histamine systems, complementing existing drugs which affect GABAA receptors and monoaminergic systems. Non-invasive brain stimulation techniques to modulate sleep and arousal are safe and show potential but require further development to be widely applicable. Invasive viral vector and deep brain stimulation approaches are also in their infancy but may be used to modulate sleep and arousal in severe neurological and psychiatric conditions. Behavioral, pharmacological, non-invasive brain stimulation and cell-specific invasive approaches covered here suggest the potential to selectively influence arousal, sleep initiation, sleep maintenance or sleep-stage specific phenomena such as sleep spindles or slow wave activity. These manipulations can positively impact the treatment of a wide range of neurological and psychiatric disorders by promoting the restorative effects of sleep on memory consolidation, clearance of toxic metabolites, metabolism, and immune function and by decreasing hyperarousal.
... Also touching, carrying, swinging, tossing, swirling has a calming effect on the parasympathetic nervous system, as noted when a baby cries and is restless (Asto, 2019), as passive transport of the body (Esposito et al., 2013). Repetitive, rocking, rhythmic motions are an unparalleled, atavistic activity that we all get to know in the womb and we intuitively associate it with safety and relaxation (Bayer et al., 2011;Korn, 2018;Tennant, 2015). Babies fall asleep easily with gentle rocking back and forth with slow wave frequency, this is because it is similar to the mother's heart rate (Hao et al., 2018) (Maruki & Kyuushu University, 2009). ...
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Overarching over both theoretical lenses as put forward by Hansen and Verkaaik (2009) and Simone and Pieterse (2017), the present paper presents a case in point of Gujjar Nala, in Karachi, focusing on aspects of urban resilience in the face of forced evictions, and the usage of creative tactics to deal with uncertainty. Gujjar Nala is a natural drainage channel which starts from North Karachi and falls into the Lyari River near Mureed Goth (village). In one of its recent efforts (Ayub, 2016) to remove the encroachments along the 28kms long nala, the Karachi Municipal Corporation (KMC) removed four thousand structure, which had been built over a period of fifty years along the Nala. According to the KMC officials the objective behind the anti-encroachment drive was to streamline the sewerage scheme of the city and smoothen the storm-water drainage system. Strangely, the rubble of the removed structures was left at the demolishing site, and eventually ended up back in the Nala, causing further blockages to the flow of sewerage and storm water. During the cycle of forced demolition of the structures, urban resilience was seen by the locals in the form of demonstrations and protests, but a year later resilience is seen in the various creative tactics that have been used to re-utilize the dismantled structures with a sense of aesthetics. The space reclaimed by the government authorities, as a result of the evictions has been re-occupied by the locals, using temporary coverings like fencing, fabric, asbestos sheets and screens, and is being used as extended living space, animal grazing, recreation, plantation and storage space. There are elements of aesthetics seen in these temporarily designed extended spaces, in the form of brightly colored painted walls, potted plants and usage of intricately designed screens. While there is rich empirical literature on the informality in housing and land use in Karachi, few studies review the aftermath of evictions, and tactics of resilience adapted by locals to survive in the face of adversity. Using the lens of creativity, this paper analysis how locals deal with insecurity and threats like eviction, to come to terms with everyday reality. The research is based on qualitative research methods, using site visits and interviews of people directly impacted by the demolition process.
... Also touching, carrying, swinging, tossing, swirling has a calming effect on the parasympathetic nervous system, as noted when a baby cries and is restless (Asto, 2019), as passive transport of the body (Esposito et al., 2013). Repetitive, rocking, rhythmic motions are an unparalleled, atavistic activity that we all get to know in the womb and we intuitively associate it with safety and relaxation (Bayer et al., 2011;Korn, 2018;Tennant, 2015). Babies fall asleep easily with gentle rocking back and forth with slow wave frequency, this is because it is similar to the mother's heart rate (Hao et al., 2018) (Maruki & Kyuushu University, 2009). ...
Chapter
The article discusses the revolutionary system of well-being—The Vinci Power Nap® and its beneficial role in increasing the quality of life and health of inhabitants in Smart Cities and astronauts. The author investigates the impact of this neuroarchitecture design on reducing levels of stress and anxiety, aiding prevention and healing of depression and PTSD, increasing quality of sleep, focus, energy, productivity, and feelings of safety. The research entailed surveys filled by UN Delegates from 58 countries who took part in VPN sessions during the Conference on Climate Change COP24. Keywords: Neuroarchitecture Interior design Smart city Stress reduction Calming senses Well-being PTSD Depression Efficiency Astronauts Regeneration Vinci Power Nap
... Also touching, carrying, swinging, tossing, swirling has a calming effect on the parasympathetic nervous system, as noted when a baby cries and is restless (Asto, 2019), as passive transport of the body (Esposito et al., 2013). Repetitive, rocking, rhythmic motions are an unparalleled, atavistic activity that we all get to know in the womb and we intuitively associate it with safety and relaxation (Bayer et al., 2011;Korn, 2018;Tennant, 2015). Babies fall asleep easily with gentle rocking back and forth with slow wave frequency, this is because it is similar to the mother's heart rate (Hao et al., 2018) (Maruki & Kyuushu University, 2009). ...
Chapter
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The future of smart city relies on technology that integrates information and communication through the foundation of rapidly growing capabilities of “Internet of Things (IoT)”. With the advancement of Virtual Reality (VR) technologies, it has emerged to become one of the most promising technology for application in various fields including architectural design, construction and property development. As VR technologies become more accessible to the consumer markets, this study is directing the potential of integrating VR technology as an interface that allows end-user’s interactions and experience the future home design, not only focuses on the visual aesthetics, physical preferences and spatial needs, but also considers the emotional well-being of future occupants. A smart city needs to be emotionally-intelligent and requires a strategy aimed at producing a humanised environment tuned to emotional needs of occupants. Drawing on the widely accepted S–O-R framework, the study is currently developing a model to illustrate the inter-relationships between a VR-simulated home environment system with emotional reaction and behavioural response of potential Smart Home buyers. The proposed framework is expected to lead towards an improved practical approach in Smart Home design while facilitating marketing for developers for future Smart Home projects in smart city development.KeywordsEmotion-IntelligentVirtual RealityBuilt Environment InformaticsSmart HomesSmart City Development
... SWS has been shown to be enhanced by sound stimuli [103][104][105][106], and this acoustic stimulation indeed affects memory recall in some patients [104]. Rocking beds have also been shown to improve sleep by reducing sleep latency, increasing SWA, and reducing nocturnal arousal in both healthy adults and MCI patients [107][108][109]. They have also been reported to be associated with improved memory in healthy subjects [110]. ...
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The majority of neurodegenerative diseases are pathologically associated with protein misfolding and aggregation. Alzheimer’s disease (AD) is a type of dementia that slowly affects memory and cognitive function, and is characterized by the aggregation of the β-amyloid protein and tau neurofibrillary tangles in the brain. Parkinson’s disease (PD) is a movement disorder typically resulting in rigidity and tremor, which is pathologically linked to the aggregation of α-synuclein, particularly in dopaminergic neurons in the midbrain. Sleep disorders commonly occur in AD and PD patients, and it can precede the onset of these diseases. For example, cognitively normal older individuals who have highly fragmented sleep had a 1.5-fold increased risk of subsequently developing AD. This suggests that sleep abnormalities may be a potential biomarker of these diseases. In this review, we describe the alterations of sleep in AD and PD, and discuss their potential in the early diagnosis of these diseases. We further discuss whether sleep disturbance could be a target for the treatment of these diseases.
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Background Patients with breast cancer (BC) exhibit circadian rhythm disruptions, mainly of rest-activity rhythm (RAR), of which sleep is an essential component, and cortisol rhythm. Sleep complaints such as insomnia and cognitive impairments are prevalent in BC. In general population, sleep is known to contribute greatly to cognition. Thus, improving RAR (and particularly sleep) could help limiting cognitive impairments in BC patients. It has recently been suggested that, in addition to its essential role in spatial memory, the vestibular system contributes to RAR synchronization. Its stimulation could therefore limit both sleep disturbances and spatial memory deficits in BC. Objectives The main aim of the ICANSLEEP-2 study is to assess the effects of galvanic vestibular stimulation (GVS) on circadian rhythms. The secondary aim is to assess whether GVS improves sleep and spatial memory in BC patients. Methods Two groups with insomnia complaints (Insomnia Severity Index > 7) will be included: a patients’ group with BC (n = 50) and a healthy control group without history of cancer (n = 25). There will be two assessment sessions, before and after 2 weeks of GVS. Patients will be randomly assigned to either a GVS group or a sham group (noneffective stimulation). Controls will receive GVS. GVS effects will be quantified and compared between groups. Assessments will include actigraphy, salivary cortisol, polysomnography, a cognitive test battery (including a computer-based task for spatial memory) and validated questionnaires (for psychological functioning and sleep complaints). Discussion Current methods for improving sleep in BC have had controversial outcomes regarding sleep structure. We expect GVS to offer a new mean of directly targeting RAR disruptions in BC patients, with beneficial effects on sleep structure. Given the crucial impact of sleep on cognitive functioning, notably spatial memory, improving sleep of BC patients should enhance their cognitive functioning. Ethics and dissemination This study received ethical approval from the Ile de France IV institutional review board on 19 April 2022 (no. ID-RCB: 2022-A00437-36). The findings yielded by this protocol will be presented at various conferences and in peer-reviewed journals. Clinicaltrials.gov registration number NCT05414357.
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In the past 20 years, more remarkable revelations about sleep and its varied functions have arguably been made than in the previous 200. Building on this swell of recent findings, this essay provides a broad sampling of selected research highlights across genetic, molecular, cellular, and physiological systems within the body, networks within the brain, and large-scale social dynamics. Based on this raft of exciting new discoveries, we have come to realize that sleep, in this moment of its evolution, is very much polyfunctional (rather than monofunctional), yet polyfunctional for reasons we had never previously considered. Moreover, these new polyfunctional insights powerfully reaffirm sleep as a critical biological, and thus health-sustaining, requisite. Indeed, perhaps the only thing more impressive than the unanticipated nature of these newly emerging sleep functions is their striking divergence, from operations of molecular mechanisms inside cells to entire group societal dynamics.
Article
Objective: The current study aims to explore the effects of sleep in the rocking bed on mood and attention.Methods: Thirty-nine young adults (14 with insomnia and 25 without insomnia) slept in the Sway Bed under three different conditions; 1) motionless condition, 2) continuously rocking condition, and 3) before-sleep rocking condition. In the motionless condition, participants slept without rocking for all night. In the continuously rocking condition, rocking started when lights out and stopped at wake-up time. In the before-sleep rocking condition, rocking started when lights out, but stopped after sleep onset. The Profile of Mood States and the computerized Comprehensive Attention Test were conducted before and after experimental sleep.Results: Under continuously rocking, depression, tension, anger, fatigue, confusion, and standard deviation of reaction time in divided attention were reduced. Under after-sleep bed condition, depression, tension, fatigue, confusion and omission errors in divided attention were reduced. There were no significant differences in after-sleep mood or attention changes between bed conditions. However, within those with insomnia, after-sleep improvement of depression and divided reduction were larger under continuously rocking conditions than under motionless conditions.Conclusion: Sleeping in the rocking bed improved negative affects and divided attention. The effects of rocking bed on depression and divided attention were prominent especially in those with insomnia. The current findings suggest that the sleep in the rocking bed may improve the depressive mood and the impaired attention of insomnia patients.
Conference Paper
Sleep is essential to boost the rehabilitation outcome as it facilitates motor learning, enhances cognitive performance, and improves mood and well-being. Rocking beds that provide vestibular stimulation may be a promising and non-invasive alternative to conventional pharmaceutical treatments for individuals with sleep problems, offering regenerative sleep without unwanted side effects. Previous research has shown that the effectiveness of the interventions is related to the chosen rocking acceleration. Moreover, the movement of the bed must be comfortable and smooth to avoid disturbing the user's sleep. Previously, the motor control parameters were tuned manually, which was time-consuming, subjective, and did not guarantee minimum deviation from the desired acceleration profile. In this work, we present an efficient and effective method using Gaussian processes to automatically tune the PI control parameters of a rocking bed moving along the longitudinal axis. We first simulated the kinematics of a rocking bed and optimized the control parameters for a chosen objective function that included the desired and the actual accelerations in the movement direction. We then compared the number of iterations needed to reach this objective for a model based on Gaussian processes and for a model based on a naive random exploration of the parameter space. Finally, we implemented the Gaussian process on the rocking bed to automatically tune the control parameters and subjectively compared them to the control parameters that were previously obtained after manual tuning. Our simulation showed that we can reach the control objective after a constant number of iterations using Gaussian processes, independent of the search space size. For the random search, the number of iterations increased quadratically with the size of the search space. The Gaussian process was found to be well transferable to the rocking bed. After less than one hour, control parameters were discovered that outperformed the previous parameters in terms of smoothness. However, despite the smoother motion, the noise emission from the motor, which was not part of the optimization, increased considerably. Our presented technique based on Gaussian processes significantly reduced the time and effort required to optimize the bed's control parameters compared to manual tuning. In future work, the control objective has to be refined to include noise emission as an optimization metric as low noise is an important aspect in sleep-related applications.
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Sleep is a familiar, periodic occurrence in our lives. Despite its place in everyday experience, the existence of this suspended state of consciousness has intrigued and puzzled philosophers and scientists for decades. For much of its history, sleep science has focused on humans and mammals. In contrast, in the last 20 years or so, it has become increasingly clear that sleep is essentially universal. Sleep states have been observed in animals from mammals to cnidaria. Here, we review recent progress in sleep science through the lens of comparative physiology. We highlight broad insights into sleep phenomenology, physiology and function that have come from this comparative approach. These include the plasticity of sleep in response to environmental challenges and ecological niches, the discovery of distinct sleep stages in diverse taxa and conserved functions of sleep. Indeed, we argue, a comparative approach is essential to any comprehensive account of sleep.
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Various stimulation systems to modulate sleep structure and function have been introduced. However, studies on the time spent in sleep initiation (TSSI) are limited. This study proposes a closed-loop auditory stimulation (CLAS) to gradually modulate respiratory rhythm linked to the autonomic nervous system (ANS) activity directly associated with sleep. CLAS is continuously updated to reflect the individual’s current respiratory frequency and pattern. Six participants took naps on different days with and without CLAS. The average values of the TSSI are 14.00 ± 4.24 and 9.67 ± 5.31 min in the control and stimulation experiments (p < 0.03), respectively. Further, the values of respiratory instability and heart rate variability differ significantly between the control and stimulation experiments. Based on our findings, CLAS supports the individuals to gradually modulate their respiratory rhythms to have similar characteristics observed near sleep initiation, and the changed respiratory rhythms influence ANS activities, possibly influencing sleep initiation. Our approach aims to modulate the respiratory rhythm, which can be controlled intentionally. Therefore, this method can probably be used for sleep initiation and daytime applications.
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Among the various sleep modulation methods for improving sleep, three methods using noninvasive stimulation during sleep have been reviewed and summarized. The first method involves noninvasive direct brain stimulation to induce a current directly in the brain cortex. Electrically or magnetically applied stimulations trigger electrical events such as slow oscillations or sleep spindles, which can also be recorded by an electroencephalogram. The second method involves sensory stimulation during sleep, which provides stimulation through the sensory pathway to invoke equivalent brain activity like direct brain stimulation. Olfactory, vestibular, and auditory stimulation methods have been used, resulting in several sleep-modulating effects, which are characteristic and depend on the experimental paradigm. The third method is to modulate sleep by shifting the autonomic balance affecting sleep homeostasis. To strengthen parasympathetic dominance, stimulation was applied to decrease heart rate by synchronizing the heart rhythm. These noninvasive stimulation methods can strengthen slow-wave sleep, consolidate declarative or procedural memory, and modify sleep macrostructure. These stimulation methods provide evidence and possibility for sleep modulation in our daily life as an alternative method for the treatment of disturbed sleep and enhancing sleep quality and performance beyond the average level.
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Objectives: Preliminary research suggests that electrical vestibular nerve stimulation (VeNS) may improve sleep outcomes by influencing the hypothalamus and brainstem nuclei involved in regulating the circadian rhythm and wakefulness. This randomised, sham-controlled trial aimed to assess the effectiveness of VeNS on insomnia in young adults. Methods: Eighty adults aged 18-24 years were randomly allocated to the intervention (n=40) and control groups (n=40). The intervention group was provided with 30 min per day of VeNS with five sessions weekly for four weeks, while the control group received sham stimulation for the same period. Baseline Insomnia Sleep Index (ISI) scores were recorded weekly. At baseline and at day 28, questionnaires to evaluate emotional states of depression, anxiety and stress, and quality of life (QoL) were completed. The primary outcome was change in ISI with comparison between baseline and day 28. Results: The VeNS group significantly reduced their mean ISI score after 7 days usage (p<0.001). At day 28 it was found that mean ISI scores had reduced from 19 to 11 in the VeNS group, and from 19 to 18 in the sham group, and the difference between the groups was significant (p<0.001). Moreover, application of VeNS appeared to significantly improve emotional state and QoL outcomes. Conclusions: This trial demonstrates that regular VeNS usage over four weeks leads to a clinically meaningful decrease in ISI scores in young adults with insomnia. VeNS may have potential as a drug-free and non-invasive therapy to improve sleep outcomes by positively influencing the hypothalamic and brainstem nuclei.
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Why we sleep remains the most fundamental question in sleep science to date, with theories ranging from restoration to regeneration of brain and body. Slow-wave sleep, the deepest form of sleep characterized by large, slow oscillations (<4 Hz) on the EEG, is considered a “powerhouse” in these respects. It has been associated with metabolism, cardiovascular health, cognition, and more recently the clearance of toxins in the brain via the glymphatic system [1, 2]. As slow-wave sleep can be reduced in certain psychiatric conditions, insufficient sleep opportunities, or advancing age, strategies to enhance it are potentially transformative for health and performance. With the new era for sleep wearable technologies upon us, sleep enhancement in the form of noninvasive stimulation technology is developing rapidly, and acoustic stimulation of sleep provides an ideal tool as a (slow wave) sleep therapeutic, but also a research tool to help understand the fundamental function of slow-wave sleep.
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The two‐process model of sleep regulation posits two main processes regulating sleep: the circadian process controlled by the circadian clock and the homeostatic process that depends on the history of sleep and wakefulness. The model has provided a dominant conceptual framework for sleep research since its publication ~ 40 years ago. The time of day and prior wake time are the primary factors affecting the circadian and homeostatic processes, respectively. However, it is critical to consider other factors influencing sleep. Since sleep is incompatible with other behaviors, it is affected by the need for essential behaviors such as eating, foraging, mating, caring for offspring, and avoiding predators. Sleep is also affected by sensory inputs, sickness, increased need for memory consolidation after learning, and other factors. Here, we review multiple factors influencing sleep and discuss recent insights into the mechanisms balancing competing needs.
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To determine if vestibular stimulation is an effective therapy for transient insomnia in a sleep phase advance model. Multi-site, double-blind, randomized, parallel-group, sham-controlled trial This study was carried out at 6 sites in the United States. 198 healthy normal sleepers. Bilateral electrical stimulation of the vestibular apparatus of the inner ear via electrodes on the skin of the mastoid process at a frequency of 0.5 Hz vs. sham stimulation. We did not find a significant effect of treatment on our primary outcome variable, latency to persistent sleep onset (LPS). However, our planned analysis identified that the mean latency to sleep onset on the multiple sleep latency test was a significant covariate. This led us to carry out post hoc analyses, which showed a significant effect of treatment on LPS in those subjects with a mean MSLT sleep onset latency > or = 14 minutes. Vestibular stimulation did not have a therapeutic effect in a model of transient insomnia in the overall population studied. However, this study provides preliminary evidence that vestibular stimulation may shorten sleep onset latency compared with sham therapy in the subset of subjects with mean MSLT sleep onset latency > or = 14 minutes.
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Throughout history, vestibular and emotional dysregulation have often manifested together in clinical settings, with little consideration that they may have a common basis. Regarding vestibular mechanisms, the role of brainstem and cerebellar structures has been emphasized in the neurological literature, whereas emotion processing in the cerebral hemispheres has been the focus in psychology. A conceptual model is proposed that links research in the 2 disparate fields by means of a functional cerebral systems framework. The claim is that frontal regions exert regulatory control over posterior systems for sensation and autonomic functions in a dense, interconnected network. Impairment at levels within the system is expected to influence vestibular and cognitive processes depending on the extent of frontal regulatory capacity. M. Kinsbourne's (1980) shared cerebral space model specifies the conditions under which dysfunction of the vestibular modality will influence higher cognitive levels. A position on laterality and associative relations within the right hemisphere is proposed to explain links among dizziness, nausea, and negative emotion.
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Sleep is influenced by diverse factors such as circadian time, affective states, ambient temperature, pain, etc., but pathways mediating these influences are unknown. To identify pathways that may influence sleep, we examined afferents to the ventrolateral preoptic nucleus (VLPO), an area critically implicated in promoting sleep. Injections of the retrograde tracer cholera toxin B subunit (CTB) into the VLPO produced modest numbers of CTB-labeled monoaminergic neurons in the tuberomammillary nucleus, raphe nuclei, and ventrolateral medulla, as well as a few neurons in the locus coeruleus. Immunohistochemistry for monoaminergic markers showed dense innervation of the VLPO by histaminergic, noradrenergic, and serotonergic fibers. Along with previous findings, these results suggest that the VLPO and monoaminergic nuclei may be reciprocally connected. Retrograde and anterograde tracing showed moderate or heavy inputs to the VLPO from hypothalamic regions including the median preoptic nucleus, lateral hypothalamic area, and dorsomedial hypothalamic nucleus (DMH), autonomic regions including the infralimbic cortex and parabrachial nucleus, and limbic regions including the lateral septal nucleus and ventral subiculum. Light to moderate inputs arose from orexin and melanin concentrating hormone neurons, but cholinergic or dopaminergic inputs were extremely sparse. Suprachiasmatic nucleus (SCN) projections to the VLPO were sparse, but the heavy input to the VLPO from the DMH, which receives direct and indirect SCN inputs, could provide an alternate pathway regulating the circadian timing of sleep. These robust pathways suggest candidate mechanisms by which sleep may be influenced by brain systems regulating arousal, autonomic, limbic, and circadian functions.
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The brain contains autochthonous neural systems that evoke waking from sleep in response to sensory stimuli, prolong or enhance arousal in response to special stimuli, and also generate and maintain wakefulness regardless of sensory stimuli during the active part of the day. Through ascending projections to the cortex, these arousal systems stimulate cortical activation, characterized by high frequency gamma and low frequency rhythmic theta activity, and through descending projections to the spinal cord, they stimulate muscle tonus along with sensory-motor responsiveness and activity. They are comprised of neuronal aggregates within the brainstem reticular formation, thalamus, posterior hypothalamus and basal forebrain, and they utilize multiple different neurotransmitters. Within the brainstem, neurons of the reticular formation, which predominantly utilize glutamate as a neurotransmitter, stimulate cortical activation by exciting the widespread projecting neurons of the nonspecific thalamo-cortical projection system, which similarly utilize glutamate, and neurons of the ventral extra-thalamic relay systems located in the posterior hypothalamus and basal forebrain, many of which also utilize glutamate. In addition, these systems have descending projections by which they can enhance or modulate muscle tonus and activity. Articulating with these are cholinergic neurons of the ponto-mesencephalic tegmentum and basal forebrain that promote cortical activation during waking and also during rapid eye movement sleep (REMS), in association therein with muscle atonia. Dopaminergic ventral mesencephalic neurons stimulate a highly motivated and positively rewarding state during waking and may also do so during REMS. In contrast, noradrenergic locus coeruleus neurons promote an aroused waking state and prevent REMS as well as slow wave sleep (SWS). Serotonergic raphe neurons promote a seemingly quiet or satiated waking state, which though exclusive of REMS, can actually be conducive to SWS. Histaminergic neurons of the posterior hypothalamus act like noradrenergic neurons in enforcing waking and are joined by neurons in the region that contain orexin, a neuropeptide recently shown to maintain waking and in absentia to be responsible for narcolepsy, or the inability to maintain wakefulness. These multiple arousal systems are grossly redundant, since no one system is absolutely necessary for the occurrence of waking; yet they are differentiated, since each plays a special role in waking and sleep. During SWS, they are submitted to an inhibitory influence arising in part at least from particular GABAergic neurons co-distributed with many neurons of the arousal systems and also concentrated within the basal forebrain and adjacent preoptic region.
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There is compelling evidence that sleep contributes to the long-term consolidation of new memories. This function of sleep has been linked to slow (<1 Hz) potential oscillations, which predominantly arise from the prefrontal neocortex and characterize slow wave sleep. However, oscillations in brain potentials are commonly considered to be mere epiphenomena that reflect synchronized activity arising from neuronal networks, which links the membrane and synaptic processes of these neurons in time. Whether brain potentials and their extracellular equivalent have any physiological meaning per se is unclear, but can easily be investigated by inducing the extracellular oscillating potential fields of interest. Here we show that inducing slow oscillation-like potential fields by transcranial application of oscillating potentials (0.75 Hz) during early nocturnal non-rapid-eye-movement sleep, that is, a period of emerging slow wave sleep, enhances the retention of hippocampus-dependent declarative memories in healthy humans. The slowly oscillating potential stimulation induced an immediate increase in slow wave sleep, endogenous cortical slow oscillations and slow spindle activity in the frontal cortex. Brain stimulation with oscillations at 5 Hz--another frequency band that normally predominates during rapid-eye-movement sleep--decreased slow oscillations and left declarative memory unchanged. Our findings indicate that endogenous slow potential oscillations have a causal role in the sleep-associated consolidation of memory, and that this role is enhanced by field effects in cortical extracellular space.
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During much of sleep, cortical neurons undergo near-synchronous slow oscillation cycles in membrane potential, which give rise to the largest spontaneous waves observed in the normal electroencephalogram (EEG). Slow oscillations underlie characteristic features of the sleep EEG, such as slow waves and spindles. Here we show that, in sleeping subjects, slow waves and spindles can be triggered noninvasively and reliably by transcranial magnetic stimulation (TMS). With appropriate stimulation parameters, each TMS pulse at <1 Hz evokes an individual, high-amplitude slow wave that originates under the coil and spreads over the cortex. TMS triggering of slow waves reveals intrinsic bistability in thalamocortical networks during non-rapid eye movement sleep. Moreover, evoked slow waves lead to a deepening of sleep and to an increase in EEG slow-wave activity (0.5–4.5 Hz), which is thought to play a role in brain restoration and memory consolidation. • consciousness • electroencephalogram • slow oscillation • bistability • perturbation
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Quality sleep is an essential part of health and well-being. Yet fractured sleep is disturbingly prevalent in our society, partly due to insults from a variety of noises [1]. Common experience suggests that this fragility of sleep is highly variable between people, but it is unclear what mechanisms drive these differences. Here we show that it is possible to predict an individual's ability to maintain sleep in the face of sound using spontaneous brain rhythms from electroencephalography (EEG). The sleep spindle is a thalamocortical rhythm manifested on the EEG as a brief 11-15 Hz oscillation and is thought to be capable of modulating the influence of external stimuli [2]. Its rate of occurrence, while variable across people, is stable across nights [3]. We found that individuals who generated more sleep spindles during a quiet night of sleep went on to exhibit higher tolerance for noise during a subsequent, noisy night of sleep. This result shows that the sleeping brain's spontaneous activity heralds individual resilience to disruptive stimuli. Our finding sets the stage for future studies that attempt to augment spindle production to enhance sleep continuity when confronted with noise.
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This study evaluated the effects of otolithic vestibular stimulation in the form of a linearly accelerated parallel swing on nighttime sleep parameters and daytime sleep tendency in eight normal subjects. The protocol consisted of one adaptation night following by two motion nights, one adaptation night followed by two stationary nights, and two Multiple Sleep Latency Tests (MSLT), one motion and one stationary. On the motion nights, there was a decrease in stage 2 percentage as well as a facilitative effect on sleep latency on the last night. In addition, an increase in the number of rapid eye movements (REMs) per night was found without a significant alteration of REM sleep amount or latency. No significant differences were found between the motion and stationary MSLT days.
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The mammalian medial vestibular nucleus (MVe) receives input from all vestibular endorgans and provides extensive projections to the central nervous system. Recent studies have demonstrated projections from the MVe to the circadian rhythm system. In addition, there are known projections from the MVe to regions considered to be involved in sleep and arousal. In this study, afferent and efferent subcortical connectivity of the medial vestibular nucleus of the golden hamster (Mesocricetus auratus) was evaluated using cholera toxin subunit-B (retrograde), Phaseolus vulgaris leucoagglutinin (anterograde), and pseudorabies virus (transneuronal retrograde) tract-tracing techniques. The results demonstrate MVe connections with regions mediating visuomotor and postural control, as previously observed in other mammals. The data also identify extensive projections from the MVe to regions mediating arousal and sleep-related functions, most of which receive immunohistochemically identified projections from the lateral hypothalamic hypocretin (orexin) neurons. These include the locus coeruleus, dorsal and pedunculopontine tegmental nuclei, dorsal raphe, and lateral preoptic area. The MVe itself receives a projection from hypocretin cells. CTB tracing demonstrated reciprocal connections between the MVe and most brain areas receiving MVe efferents. Virus tracing confirmed and extended the MVe afferent connections identified with CTB and additionally demonstrated transneuronal connectivity with the suprachiasmatic nucleus and the medial habenular nucleus. These anatomical data indicate that the vestibular system has access to a broad array of neural functions not typically associated with visuomotor, balance, or equilibrium, and that the MVe is likely to receive information from many of the same regions to which it projects.
  • T C Chou
  • A A Bjorkum
  • S E Gaus
  • J Lu
  • T E Scammell
Chou, T.C., Bjorkum, A.A., Gaus, S.E., Lu, J., Scammell, T.E., and Saper, C.B. (2002).
The sleep-waking cycle
  • G Moruzzi
  • R H Pharmacology
  • E Adrian
  • H Helmreich
  • R Holzer
  • K Young
  • O Kramer
  • F Kreayer
  • P A Lynen
  • Miescher
Moruzzi, G. (1972). The sleep-waking cycle. In Reviews of Physiology: Biochemistry and experimental pharmacology, R.H. Adrian, E. Helmreich, H. Holzer, R. Young, K. Kramer, O. Kreayer, F. Lynen, P.A. Miescher, H. Rasmussen, A.E. Renold, et al., eds. (Berlin, Heidelberg, New York: Springer-Verlag), pp. 1-165.