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Rocking synchronizes brain waves during a short nap
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
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]. 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.
... 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). ...
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.
... On démontre une perturbation du rythme circadien de l'activité motrice chez une population de patients aréflexiques vestibulaires bilatéraux en comparaison à des sujets sains . Enfin, la stimulation vestibulaire serait capable d'influencer le cycle veille/sommeil en particulier la transition entre ces deux états ainsi que l'architecture du sommeil (Bayer et al., 2011;Kompotis et al., 2019). ...
... Néanmoins les preuves empiriques divergent. Des études révèlent que la stimulation vestibulaire favoriserait le sommeil (Bayer et al., 2011;Woodward, Tauber, Spielmann, & Thorpy, 1990) tandis que d'autres démontrent son implication dans la veille (Campos, 1994). L'induction d'un état de veille ou de sommeil dépend principalement des paramètres de stimulation utilisés (Winter et al., 2013 ;Kumar & Mukkadan, 2015). ...
... On observe une amélioration de la transition veille/sommeil lors d'une sieste ou d'une nuit dans un lit en mouvement (i.e. balancement) par rapport à un lit stationnaire (Bayer et al., 2011;Woodward et al., 1990). Le temps passé dans le sommeil de stade 1 ainsi que la latence du stade 2 diminuent lors d'une sieste de quarante-cinq minutes en condition balancement (Bayer et al., 2011). ...
L’objectif de ce travail de thèse était de tester si la stimulation vestibulaire peut influencer les rythmes biologiques circadiens chez l’Homme. Pour répondre à cet objectif, nous avons évalué les effets de deux techniques de stimulation vestibulaire (fauteuil rotatoire et Stimulation Vestibulaire Galvanique/SVG) sur le rythme de l’activité motrice de sujets jeunes sains. Ce projet a également évalué la tolérabilité des protocoles appliqués. La proximité de la technique de SVG avec la stimulation transcrânienne à courant direct (tDCS) utilisée dans les troubles de l’humeur ainsi que les liens entre les troubles des rythmes biologiques et de l’humeur nous ont conduits à évaluer les effets de la stimulation vestibulaire sur le niveau d’anxiété.Une première étude a permis de démontrer que la stimulation induite par un fauteuil rotatoire en fin de journée provoque une diminution du niveau d’activité motrice, ainsi qu’une avance de phase du rythme de l’activité motrice deux jours après la stimulation. Une seconde étude a montré que la SVG appliquée en milieu de journée n’a pas d’effets significatifs sur le rythme de l’activité motrice et la transition entre les états de veille et de sommeil. Enfin, une troisième étude a permis de montrer que la SVG diminue le niveau d’anxiété et que cet effet dépend des paramètres de stimulation appliqués (durée). La technique de SVG est bien tolérée par les participants contrairement à la stimulation sur fauteuil rotatoire qui provoque une augmentation des symptômes de mal des transports.Ces résultats confirment que la stimulation vestibulaire peut être utilisée pour moduler les rythmes biologiques et l’humeur chez l’Homme. Cependant, les effets observés dépendent des paramètres de stimulation appliqués (technique de stimulation, moment de la journée). Ces résultats encouragent la poursuite des investigations concernant l’utilisation de la stimulation vestibulaire comme synchroniseur des rythmes biologiques et la SVG comme outil potentiel de réhabilitation des rythmes biologiques et de l’humeur.
... To date, various open-loop stimulation methods have been used to elucidate sleep characteristics [16][17][18][19][20][21][22][23][24][25][26][27][28]. Among them, one study [16] revealed the mechanism and role of sleep spindle waves by applying a spike stimulus to the thalamus to induce sleep spindles. ...
... Moreover, olfactory sensory stimulation was applied in sleep studies [22][23][24], and researchers reported enhanced slow wave sleep (SWS) [22], delta activity, and spindle activity [23] as a result of olfactory stimulation. Arzi et al. [24] observed positive behavioral change (cigarette-smoking cessation) after aversive olfactory conditioning during non-rapid eye movement (NREM) sleep stage 2. Vestibular stimulation using electrical stimulation [25] and an actual rocking bed [26,27] were tested during sleep; the authors reported shortened sleep onset [25], increased amount of NREM sleep stage 2, and spindle density [26]. Omlin and colleagues also observed an increased number of spindles during the stimulation but found no effect on sleep onset or memory consolidation [27]. ...
... Moreover, olfactory sensory stimulation was applied in sleep studies [22][23][24], and researchers reported enhanced slow wave sleep (SWS) [22], delta activity, and spindle activity [23] as a result of olfactory stimulation. Arzi et al. [24] observed positive behavioral change (cigarette-smoking cessation) after aversive olfactory conditioning during non-rapid eye movement (NREM) sleep stage 2. Vestibular stimulation using electrical stimulation [25] and an actual rocking bed [26,27] were tested during sleep; the authors reported shortened sleep onset [25], increased amount of NREM sleep stage 2, and spindle density [26]. Omlin and colleagues also observed an increased number of spindles during the stimulation but found no effect on sleep onset or memory consolidation [27]. ...
Advances in computer processing technology have enabled researchers to analyze real-time brain activity and build real-time closed-loop paradigms. In many fields, the effectiveness of these closed-loop protocols has proven to be better than that of the simple open-loop paradigms. Recently, sleep studies have attracted much attention as one possible application of closed-loop paradigms. To date, several studies that used closed-loop paradigms have been reported in the sleep-related literature and recommend a closed-loop feedback system to enhance specific brain activity during sleep, which leads to improvements in sleep’s effects, such as memory consolidation. However, to the best of our knowledge, no report has reviewed and discussed the detailed technical issues that arise in designing sleep closed-loop paradigms. In this paper, we reviewed the most recent reports on sleep closed-loop paradigms and offered an in-depth discussion of some of their technical issues. We found 148 journal articles strongly related with ‘sleep and stimulation’ and reviewed 20 articles on closed-loop feedback sleep studies. We focused on human sleep studies conducting any modality of feedback stimulation. Then we introduced the main component of the closed-loop system and summarized several open-source libraries, which are widely used in closed-loop systems, with step-by-step guidelines for closed-loop system implementation for sleep. Further, we proposed future directions for sleep research with closed-loop feedback systems, which provide some insight into closed-loop feedback systems.
... Anecdotal observations suggest that babies sleep better when gently rocked or bounced and people tend to fall asleep during long car rides. Several experimental studies have confirmed that rocking promotes sleep in infants, adult humans, and mice (Bayer et al., 2011;Kompotis et al., 2019;Korner et al., 1978;Perrault et al., 2019). Yet the underlying mechanisms are not well understood. ...
... A prevailing model of how sensory stimulation promotes sleep, which we will term the synchronization model, is that it enhances the synchronous neural activity and boosts sleep slow waves (Bellesi et al., 2014;Perrault et al., 2019). Transcranial direct current stimulation and transcranial magnetic stimulation of the cortex have shown that synchronized brain activity can enhance sleep slow waves (Marshall et al., 2006;Massimini et al., 2007), and several studies in humans and mice have found sleep-promoting effects of rocking and brief tones delivered at low frequencies (≤ 1.5 Hz) (Bayer et al., 2011;Kompotis et al., 2019;Perrault et al., 2019;Tononi et al., 2010). ...
... In addition to 20 Hz and 200 Hz vibrations administered separately, we included 3 Hz and 8 Hz vibrations. We used 3 Hz because it is close to the frequency range used in mammalian studies of rocking (Bayer et al., 2011;Kompotis et al., 2019;Perrault et al., 2019), and 8 Hz because a previous electrophysiological study found that the fly brain sometimes exhibits 7-10 Hz oscillations during sleep (Yap et al., 2017). Vibrations at all four frequencies were capable of inducing sleep, at least in some control strains ( Figures 6C). ...
People tend to fall asleep when gently rocked or vibrated. Experimental studies have shown rocking promotes sleep in humans and mice. The prevailing "synchronization" model proposes synchronization of brain activity to mechanosensory stimuli mediates the phenomenon. The alternative "habituation" model proposes habituation, a form of non-associative learning, mediates sleep induction by monotonous stimulation. Here we show that gentle vibration promotes sleep in Drosophila in part through habituation. Vibration-induced sleep (VIS) leads to the accrual of homeostatic sleep credit, is associated with reduced arousability, and can be suppressed by heightened arousal. Sleep induction improves over successive blocks of vibration and exhibits stimulus specificity, supporting the habituation model. Multiple mechanosensory organs mediate VIS, and the magnitude of sleep gain depends on the vibration frequency and genetic background. Our findings suggest habituation is a major contributor to VIS, but synchronization of brain activity may play a role under certain stimulus conditions.
... 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)). ...
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 ...
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. ...
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. ...
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.
... Alternatively, SO could be induced through closed-loop auditory stimulation in synchrony with endogenous brain activity, thereby enhancing SO, improving memory consolidation [8,9], and intensifying sleepregulated immune function [10]. In addition, previous studies [11,12] showed that a rhythmic rocking stimulation, in which an electrical motor produced a lateral excursion to the bed, increased synchronized brain oscillations (i.e. sleep spindles and SO) and strengthened SWS and memory. ...
... The power spectra were normalized by dividing the cumulative power up to 30 Hz to account for individual variability. The mean power was computed for the following frequency bands: slow-wave activity (SWA, 0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sigma (12)(13)(14)(15)(16), and beta (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). The power levels of the abovementioned frequency bands were extracted from the WASO, N1, N2, SWS, and REM sleep stage, and the difference between the relative band powers of the SHAM and STIM were compared. ...
Sleep is a unique behavioral state that affects body functions and memory. Although previous studies suggested stimulation methods to enhance sleep, a new method is required that is practical for long-term and unconstrained use by people. In this study, we used a novel closed-loop vibration stimulation method that delivers stimulus in interaction with the intrinsic heart rhythm and examined the effects of stimulation on sleep and memory. Twelve volunteers participated in the experiment and each underwent one adaptation night and two experimental conditions—a stimulation condition (STIM) and no-stimulation condition (SHAM). The heart rate variability analysis showed a significant increase in the nHF and the nLF significantly decreased under the STIM during the slow-wave sleep (SWS) stage. Furthermore, the synchronization ratio between the heartbeat and the stimulus significantly increased under the STIM in the SWS stage. From the electroencephalogram (EEG) spectral analysis, EEG relative powers of slow-wave activity and theta frequency bands showed significant increase during the STIM in the SWS stage. Additionally, the memory retention significantly increased under the STIM compared to the SHAM. These findings suggest that the closed-loop stimulation improves the SWS-stage depth and memory retention, and further provides a new technique for sleep enhancement.
... In humans, vestibular stimulation through swinging has demonstrated an accelerated effect in the wake/sleep transition and have highlighted sleep consolidation during napping (Bayer et al. 2011). Otolith stimulation induced by accelerated linear bed movements seems to have a potential effect on drowsiness (Crivelli et al. 2016;Woodward et al. 1990). ...
... This technic naturally stimulates the vestibular system compared to the caloric vestibular stimulation or galvanic vestibular stimulation. Some studies focusing on the effects of swinging beds have used similar methods to induce canalicular and/or otolithic stimulation (Bayer et al. 2011;Woodward et al. 1990). However, this technique induces significant motion sickness symptoms, and 6 participants had to stop the experiment due to severe symptoms. ...
The vestibular system is responsible for sensing every angular and linear head acceleration, mainly during periods of motor activity. Previous animal and human experiments have shown biological rhythm disruptions in small rodents exposed to a hypergravity environment, but also in patients with bilateral vestibular loss compared to a control population. This raised the hypothesis of the vestibular afferent influence on circadian rhythm synchronization. The present study aimed to test the impact of vestibular stimulation induced by a rotatory chair on the rest/activity rhythm in human subjects. Thirty-four healthy adults underwent both sham (SHAM) and vestibular stimulation (STIM) sessions scheduled at 18:00 h. An off-vertical axis rotation on a rotatory chair was used to ecologically stimulate the vestibular system by head accelerations. The rest/activity rhythm was continuously registered by actigraphy. The recording started one week before the first session (BASELINE), continued in the week between the two sessions and one week after the second session. Vestibular stimulation caused a significant decrease in the average activity level in the evening following the vestibular stimulation. A significant phase advance in the rest/activity rhythm occurred two days after the 18:00 h vestibular stimulation session. Moreover, the level of motion sickness symptoms increased significantly after vestibular stimulation. The present study confirms previous results on the effect of vestibular stimulation and the role of vestibular afferents on circadian biological rhythmicity. Our results support the hypothesis of the implication of vestibular afferents as non-photic stimuli acting on circadian rhythms.
... Vestibular stimulation promotes sleep through relaxation effect, through direct and indirect connections with amygdala, sensory systems, thalamus, hypothalamus and brain stem areas [10]. Swinging has been reported to alter physiological parameters of sleep [11]. Vestibular stimulation facilitates thalamo-cortical-synchronization, decreases latency of sleep and increases duration of deep sleep stages [11]. ...
... Swinging has been reported to alter physiological parameters of sleep [11]. Vestibular stimulation facilitates thalamo-cortical-synchronization, decreases latency of sleep and increases duration of deep sleep stages [11]. Vestibular stimulation regulates eating behavior through its connections with hypothalamus, dorsal raphe nucleus, nucleus tractus solitarius, locuscoeruleus and hippocampal formation [12]. ...
... [101] Recent research reported that natural vestibular stimulation decreases sleep latency and speed up the transition from wakefulness to sleep. [102] Increase in the rapid eye movement sleep was reported followed by vestibular stimulation. [103] Vestibular stimulation influences the sleep-wake cycle through its projections to hypocretin neurons, thalamus. ...
... [103] Vestibular stimulation influences the sleep-wake cycle through its projections to hypocretin neurons, thalamus. [100,102] Vestibular stimulation not only influences sleep but also changes the pattern of dreams as reported in research that participants experienced dreams with sexual nature followed by vestibular stimulation. [104,105] Vestibular stimulation was reported to induce lucid dreams which is used in the treatment of psychiatric disorders like depression. ...
... 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]. ...
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). ...
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]. ...
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. ...
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 ...
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). ...
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. ...
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. ...
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). ...
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). ...
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). ...
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]. ...
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.
... However, while the modulatory effects of TMS are topographically accurate [212,213], its demanding setup actually reduces the possibility of a nocturnal application outside of an experimental or clinical laboratory. On the other hand, recent studies suggest that NREM sleep oscillations can be enhanced by rocking stimulation [214][215][216], with a beneficial effect on memory consolidation [216]. If the potential beneficial effect of this strategy on sleep physiology and memory processes will be confirmed, their investigation in healthy and pathological aging should be considered. ...
The multifactorial nature of Alzheimer’s disease (AD) has led scientific researchers to focus on the modifiable and treatable risk factors of AD. Sleep fits into this context, given the bidirectional relationship with AD confirmed by several studies over the last years. Sleep disorders appear at an early stage of AD and continue throughout the entire course of the pathology. Specifically, sleep abnormalities, such as more fragmented sleep, increase in time of awakenings, worsening of sleep quality and primary sleep disorders raise with the severity and progression of AD. Intervening on sleep, therefore, means acting both with prevention strategies in the pre-clinical phase and with treatments during the course of the disease. This review explores sleep disturbances in the different stages of AD, starting from the pre-clinical stage. Particular attention is given to the empirical evidence investigating obstructive sleep apnea (OSA) disorder and the mechanisms overlapping and sharing with AD. Next, we discuss sleep-based intervention strategies in the healthy elderly population, mild cognitive impairment (MCI) and AD patients. We mention interventions related to behavioral strategies, combination therapies, and bright light therapy, leaving extensive space for new and raising evidence on continuous positive air pressure (CPAP) treatment effectiveness. Finally, we clarify the role of NREM sleep across the AD trajectory and consider the most recent studies based on the promising results of NREM sleep enhancement, which use innovative experimental designs and techniques.
... Finally, there have been recent developments in the technologies targeting the enhancement of sleep spindles including transcranial direct current stimulation (Ladenbauer et al. 2017) and pharmacological agents (Mednick et al. 2013). While in this study, we did not find an association between slow wave activity and SDMC performance, devices that have been designed to target the coupling of slow waves and spindles may have value (Bayer et al. 2011;Ngo et al. 2013), though further research is required. ...
This study aimed to determine if, relative to cognitively healthy controls, sleep-dependent memory consolidation (SDMC) is diminished in mild cognitive impairment (MCI), a group at high risk of conversion to dementia. We also sought to determine whether SDMC is associated with sleep characteristics, daytime episodic memory, and hippocampal integrity. Participants with MCI (n = 43) and controls (n = 20) underwent clinical and neuropsychological profiling. From polysomnography, apnea hypopnea index (AHI) and non-REM sleep spindle characteristics were derived. From magnetic resonance imaging, hippocampal subfield volumes were computed. Participants learned a novel 32-item word-pair prior to sleep; morning retention of the word-pairs was used to determine SDMC. Results showed that SDMC did not differ between MCI and controls, but there was a large effect size decrement in SDMC in those with multiple domain MCI (Hedge's g = 0.85). In MCI, poorer SDMC was correlated with CA1 and CA3 hippocampal atrophy, shorter spindle duration, and worse daytime episodic memory. In controls, poorer SDMC was associated with higher AHI. Impaired daytime memory consolidation, reduced hippocampal volumes, shorter sleep spindles, and greater sleep apnea severity are indicators of diminished SDMC in older adults and should be explored in future studies.
... [40][41][42] Also in healthy sleeper, sleep improvements (extension of SWS and increases of SWA) are possible for example, using music, 29,43 hypnotic suggestions, 44,45 or rocking bed movements). 46 Some participants also reported that they generated sleep-related thoughts (eg, "fall asleep fast"), which is in line with a paradoxical negative rebound. 12 Previous studies have suggested that wanting to fall asleep, prolongs sleep latency and impairs sleep quality, [47][48][49] as the intention to fall asleep fast can generate cognitive arousal which impairs sleep. ...
Purpose:
Sleep is regulated by homeostatic and circadian factors. In addition, psychological factors have a strong modulatory impact on our sleep, but the exact underlying mechanisms are still largely unknown. Here, we examined the role of intentions on subjective and objective sleep parameters. Young healthy sleepers were instructed to voluntarily either worsen or improve their sleep. We predicted that participants would be capable of worsening, but not improving, their sleep compared to a regular sleep condition. In addition, we predicted that the instruction to alter sleep would lead to a higher discrepancy between subjective and objective sleep variables.
Participants and methods:
Twenty-two healthy students participated in one adaptation and three experimental nights. Polysomnography and subjective sleep parameters were measured during all four nights. Participants were instructed to sleep regularly ("neutral"), better ("good") or worse ("bad") than normal, in a counterbalanced order.
Results:
The instruction to sleep "bad" increased objective sleep onset latency and the number of awakings during the night. The effects were stronger on subjective sleep variables, resulting in a higher sleep misperception in the "bad" condition as compared to the other two conditions. The instruction to sleep "good" did not improve sleep nor did it affect sleep misperception.
Conclusion:
We conclude that intention is sufficient to impair (but not improve) subjective and objective sleep quality and to increase sleep misperception in healthy young sleepers. Our results have important implications for the understanding of the impact of psychological factors on our sleep.
... 4 On the other hand, objective measures of sleep quality have been obtained while participants took a nap in a rocking bed. These studies suggest a positive effect of hammock swinging on sleep quality (decreases sleep latency, increases N2 sleep stage and delta wave pulses) 5 and vestibular imagery during dreaming 6 ; but they do not explain the effects of regular hammock use during sleep at night, when it is commonly used in many countries. ...
Objectives
To compare and predict sleep quality between bed and hammock users .
Design
Cross-sectional pilot study.
Setting
Habitual hammock and bed users of southern Mexico.
Participants
Sixty-eight college students (53% female, mean age 21 ± 1.6 years); 33 usually sleep in bed and 35 in hammock.
Intervention
Not applicable.
Measurements
Objective sleep measures were obtained using an actigraphy device on 7 consecutive days. Questionnaires about sleep habits and sleepiness (Epworth scale) were completed. Body mass index (BMI) was obtained with a weighing machine and altimeter.
Results
Subjective sleep measures between habitual hammock and bed users were not significant (P > .05). Differences were found on 2 objective sleep measures: (1) activity index, on which hammock users obtained 7.62 minutes more than bed users (M = 36.72, standard deviation [SD] = 10.86 vs M = 44.34, SD = 13.08, P = .018) and (2) mean sleep episodes, on which hammock users had 19.67 minutes less than bed users (M = 71.52, SD = 34.37 vs M = 51.85, SD = 24.29, P = .014). Hammock users had a higher BMI than bed users (M = 23.38, SD = 3.45 vs M = 26.20, SD = 4.86, P = .010). Sex and BMI were included in the predictive model of linear regression (P < .05) of the sleep actigraphy parameters, the sleeping device was excluded of final model.
Conclusions
Hammock users show increased BMI, higher activity index and shorter mean sleep episodes than bed users. However, sex and BMI were stronger predictors of actigraphy parameters than bed type.
... Understanding what causes RMD is limited to hypotheses (Manni and Terzaghi 2005). As rhythmic sensory stimulation is known to be soothing and relaxing, (Vrugt and Pederson 1973;Grabherr et al. 2015;Omlin et al. 2016) and promotes sleep in infants and young adults, (Barnard and Bee 1983;Bayer et al. 2011;Shibagaki et al. 2017) it has been suggested that RMD might be a learned soothing, (Haywood and Hill 2012) or selfstimulating, behaviour that becomes habitual and compulsive (Clark and Chee 1977;Sallustro and Atwell 1978). At the same time, rhythmic movements might also promote early motor development (Clark and Chee 1977;Sallustro and Atwell 1978). ...
Background
Sleep-related rhythmic movement disorder is characterized by repetitive gross-motor movements at sleep onset or during sleep, which result in clinical consequences such as impact on daytime functioning and injury. No well-established therapies exist today. Substituting the patient’s movements with external sensory stimulation may offer a treatment modality. The aim of the current study was to test the feasibility and acceptability of vestibular stimulation using a rocking bed (Somnomat) in children with rhythmic movement disorder and to assess children’s movement preference.
Methods
Children with rhythmic movement disorder (n = 6, Age: 5–14 years) were studied over three nights in a sleep laboratory: adaptation night (normal bed) and randomised-order baseline (Somnomat) and intervention nights (Somnomat). Child’s preferred movement direction (head-to-toe or side-to-side) and frequency (between 0.25 and 2 Hz), determined during an afternoon protocol, were applied using the Somnomat for 1 h after lights out, and in response to subsequent episodes of rhythmic movement during intervention nights. Comfort assessed using a questionnaire, and objective sleep parameters assessed using videosomnography, were compared.
Results
The participants’ sometimes violent rhythmic movements did not disturb device performance. All children rated intervention nights equally or more comfortable than baseline nights. Self-reported sleep quality, as well as the number and duration of movement episodes did not significantly differ between baseline and intervention nights.
Conclusions
Providing rocking movements using the Somnomat is both technically feasible and acceptable to the target population. The therapeutic value of this novel stimulus substitution for rhythmic movement disorder should now be evaluated in a larger sample over a longer period in the home setting.
... Electrical stimulation of the vestibular sense opens up opportunities for rocking subjects to sleep with wearable electronics and influencing sense of balance in simulated dream bodies. Sleep neuroscience research has shown that sensations of swinging can modulate physiological parameters of sleep, easing sleep onset and inducing a sustained boosting of slow oscillations and spindle activity (Bayer et al., 2011). It is proposed that the swinging motion exerts a synchronizing action in the brain that reinforces endogenous sleep rhythms-yet this study required physically rocking a whole bed. ...
We explore the application of a wide range of sensory stimulation technologies to the area of sleep and dream engineering. We begin by emphasizing the causal role of the body in dream generation, and describe a circuitry between the sleeping body and the dreaming mind. We suggest that nearly any sensory stimuli has potential for modulating experience in sleep. Considering other areas that might afford tools for engineering sensory content in simulated worlds, we turn to Virtual Reality (VR). We outline a collection of relevant VR technologies, including devices engineered to stimulate haptic, temperature, vestibular, olfactory, and auditory sensations. We believe these technologies, which have been developed for high mobility and low cost, can be translated to the field of dream engineering. We close by discussing possible future directions in this field and the ethics of a world in which targeted dream direction and sleep manipulation are feasible.
... Experiments to counter such impairments by enhancing sleep are highly topical and have been successfully trialled with several stimulation modalities in young and older adults [28][29][30][31][32] . Auditory closed-loop stimulation has proven to be a particularly promising technique 33 , which consists of detecting endogenous SOs and applying brief auditory stimuli during their positive peaks. ...
Study Objectives: Cortical slow oscillations (SOs) and thalamo-cortical sleep spindles hallmark slow wave sleep and facilitate memory consolidation, both of which are reduced with age. Experiments utilising auditory closed-loop stimulation to enhance these oscillations showed great potential in young and older subjects. However, the magnitude of responses has yet to be compared between these age groups. We examined the possibility of enhancing SOs and performance on different memory tasks in a healthy middle-aged population using this stimulation and contrast effects to younger adults.
Methods: In a within-subject design, 17 subjects (55.7±1.0 years) received auditory stimulation in synchrony with SO up-states, which was compared to a no-stimulation sham condition. Overnight memory consolidation was assessed for declarative word-pairs and procedural finger-tapping skill. Post-sleep encoding capabilities were tested with a picture recognition task. Electrophysiological effects of stimulation were compared to a previous younger cohort (n = 11, 24.2±0.9 years).
Results: Overnight retention and post-sleep encoding performance of the older cohort revealed no beneficial effect of stimulation, which contrasts with the enhancing effect the same stimulation protocol had in our younger cohort. Auditory stimulation prolonged endogenous SO trains and induced sleep spindles phase-locked to SO up-states in the older population. However, responses were markedly reduced compared to younger subjects. Additionally, the temporal dynamics of stimulation effects on SOs and spindles differed between age groups.
Conclusions: Our findings suggest that the susceptibility to auditory stimulation during sleep drastically changes with age and reveal the difficulties of translating a functional protocol from younger to older populations.
... Experiments to counter such impairments by enhancing sleep are highly topical and have been successfully trialled with several stimulation modalities in young and older adults [28][29][30][31][32] . Auditory closed-loop stimulation has proven to be a particularly promising technique 33 , which consists of detecting endogenous SOs and applying brief auditory stimuli during their positive peaks. ...
Study Objectives
Cortical slow oscillations (SOs) and thalamo-cortical sleep spindles hallmark slow wave sleep and facilitate memory consolidation, both of which are reduced with age. Experiments utilising auditory closed-loop stimulation to enhance these oscillations showed great potential in young and older subjects. However, the magnitude of responses has yet to be compared between these age groups. We examined the possibility of enhancing SOs and performance on different memory tasks in a healthy middle-aged population using this stimulation and contrast effects to younger adults.
Methods
In a within-subject design, 17 subjects (55.7±1.0 years) received auditory stimulation in synchrony with SO up-states, which was compared to a no-stimulation sham condition. Overnight memory consolidation was assessed for declarative word-pairs and procedural finger-tapping skill. Post-sleep encoding capabilities were tested with a picture recognition task. Electrophysiological effects of stimulation were compared to a previous younger cohort (n = 11, 24.2±0.9 years).
Results
Overnight retention and post-sleep encoding performance of the older cohort revealed no beneficial effect of stimulation, which contrasts with the enhancing effect the same stimulation protocol had in our younger cohort. Auditory stimulation prolonged endogenous SO trains and induced sleep spindles phase-locked to SO up-states in the older population. However, responses were markedly reduced compared to younger subjects. Additionally, the temporal dynamics of stimulation effects on SOs and spindles differed between age groups.
Conclusions
Our findings suggest that the susceptibility to auditory stimulation during sleep drastically changes with age and reveal the difficulties of translating a functional protocol from younger to older populations.
... In the last years, other sensorial stimulation approaches have been used to modulate the physiology of the sleeping brain and potentially improve cognition (for review, see [1,36]). Vestibular stimulation (i.e., slow bed rocking (0.25 Hz)) has been successfully applied to boost SOs and spindle activity [75,76], linked to a benefit on declarative memory consolidation [76]. Moreover, odor delivery (e.g., lavender oil scent) has proved to induce SWA and spindle enhancement [77]. ...
Sleep represents a crucial time window for the consolidation of memory traces. In this view, some brain rhythms play a pivotal role, first of all the sleep slow waves. In particular, the neocortical slow oscillations (SOs), in coordination with the hippocampal ripples and the thalamocortical spindles, support the long-term storage of the declarative memories. The aging brain is characterized by a disruption of this complex system with outcomes on the related cognitive functions. In recent years, the advancement of the comprehension of the sleep-dependent memory consolidation mechanisms has encouraged the development of techniques of SO enhancement during sleep to induce cognitive benefits. In this review, we focused on the studies reporting on the application of acoustic or electric stimulation procedures in order to improve sleep-dependent memory consolidation in older subjects. Although the current literature is limited and presents inconsistencies, there is promising evidence supporting the perspective to non-invasively manipulate the sleeping brain electrophysiology to improve cognition in the elderly, also shedding light on the mechanisms underlying the sleep-memory relations during healthy and pathological aging.
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.
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.
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.
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.
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.
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.
The neuronal and genetic bases of sleep, a phenomenon considered crucial for well-being of organisms, has been under investigation using the model organism Drosophila melanogaster Although sleep is a state where sensory threshold for arousal is greater, it is known that certain kinds of repetitive sensory stimuli, such as rocking, can indeed promote sleep in humans. Here we report that orbital motion-aided mechanosensory stimulation promotes sleep of male and female Drosophila, independent of the circadian clock, but controlled by the homeostatic system. Mechanosensory receptor nanchung (Nan)-expressing neurons in the chordotonal organs mediate this sleep induction: flies in which these neurons are either silenced or ablated display significantly reduced sleep induction on mechanosensory stimulation. Transient activation of the Nan-expressing neurons also enhances sleep levels, confirming the role of these neurons in sleep induction. We also reveal that certain regions of the antennal mechanosensory and motor center in the brain are involved in conveying information from the mechanosensory structures to the sleep centers. Thus, we show, for the first time, that a circadian clock-independent pathway originating from peripherally distributed mechanosensors can promote daytime sleep of flies Drosophila melanogaster Significance Statement:Our tendency to fall asleep in moving vehicles or the practice of rocking infants to sleep suggests that slow rhythmic movement can induce sleep, although we do not understand the mechanistic basis of this phenomenon. We find that gentle orbital motion can induce behavioral quiescence even in flies, a highly genetically tractable system for sleep studies. We demonstrate that this is indeed true sleep based on its rapid reversibility by sensory stimulation, enhanced arousal threshold, and homeostatic control. Furthermore, we demonstrate that mechanosensory neurons expressing a TRPV channel nanchung, located in the antennae and chordotonal organs, mediate orbital motion-induced sleep by communicating with antennal mechanosensory motor centers, which in turn may project to sleep centers in the brain.
Background Sleep disorders are a condition affecting quality and quantity of sleep. Children with cerebral palsy (CP) have higher risk of sleep disorders than those with no chronic disease.
Objective To determine the prevalence and factors associated with sleep disorders in children with CP.
Methods We conducted an analytic, observational study with cross-sectional design in children aged 4-10 years with CP. Subjects were recruited consecutively; children with chronic diseases (cardiovascular, malignancy, chronic obstructive pulmonary disease, and diabetes mellitus) were excluded from the study. Primary data including sociodemographics, intensity of physiotherapy outside Sardjito General Hospital (SGH), sleep hygiene, and sleep disorders were collected from the Children’s Sleep Habit Questionnaire (CSHQ). Secondary data were acquired from medical records, such as type of CP, severity of motor function impairment, presence of epilepsy, intensity of physiotherapy performed at SGH, as well as anti-epileptic, anti-spastic, and sleep-affecting medicines.
Results We found sleep disorders in 64 of 75 (85%) subjects, mostly bedtime resistance (66%). Spastic quadriplegia (OR=3.63; 95%CI 1.82 to15.94) and presence of epilepsy (OR=7.82; 95%CI 1.53 to 39.84) were significantly associated with sleep disorders in children with CP aged 4-10 years.
Conclusion Sleep disorders are common in children with CP, with the majority experiencing bedtime resistance. Sleep disorders are more prevalent in subjects with spastic quadriplegia and epilepsy.
Objective
To analyze and identify differences in sleep spindles in children with restless sleep disorder (RSD), restless legs syndrome (RLS) and normal controls.
Methods
PSG (polysomnography) from children with RSD, RLS and normal controls were analyzed. Sleep spindle activity was detected on one frontal and one central electrode, for each epoch of N2 and N3 sleep. Sleep spindle density, duration and intensity (density×duration) were then obtained and used for analysis.
Results
Thirty-eight children with RSD, twenty-three children with RLS and twenty-nine controls were included. The duration of frontal spindles in sleep stage N2 was longer in children with RSD than in controls. Frontal spindle density and intensity tended to be increased in RSD children. No significant differences were found for central spindles.
Conclusion
Children with RSD had longer frontal spindles. This finding may contribute to explain the occurrence of excessive movement activity during sleep and the presence of daytime symptoms.
Significance
Recent research has demonstrated that children with RSD have increased NREM instability and sympathetic activation during sleep. Analyzing sleep spindles in children with RSD in comparison with children with RLS and controls adds to our understanding of the pathophysiology or RSD and its effects on daytime impairment.
To promote better sleep, we designed a motion mattress producing slow and swaying movements by slow regional changes of height generated by 10 separated air cells underneath. The motion induces a stretching movement and a gentle swaying movement of the user’s body. In this study, we examined its sleep-improving effects. Subjects who were not fully satisfied with their sleep were recruited. The study was performed for three periods, each of which was a week with a distinct condition. The first period was assigned as pre-experimental (PRE) period when the subjects sleep using their own mattress. The other two periods were assigned as motion mattress active (MM1) period and motion mattress control period. All subjects were randomly divided into two groups for a cross-over study. The subjects recorded electroencephalograms at home for themselves during these 3 weeks. Subjects were asked to perform sleep questionnaires. We examined the effects of this motion mattress at home by measuring the subjective and objective sleep parameters of 11 subjects. As for the objective sleep parameters, Sleep efficiency, NREM sleep stage 3, and awakening index significantly improved during MM1 compared with PRE (p < 0.05). As for the subjective sleep quality, subjects gave significantly higher value to the questions about “falling asleep quickly”, “slept soundly”, and “woke up refreshed”. Our newly developed motion mattress improved both objective and subjective sleep parameters.
People tend to fall asleep when gently rocked or vibrated. Experimental studies have shown that rocking promotes sleep in humans and mice. However, the mechanisms underlying the phenomenon are not well understood. A habituation model proposes that habituation, a form of non-associative learning, mediates sleep induction by monotonous stimulation. Here, we show that gentle vibration promotes sleep in Drosophila in part through habituation. Vibration-induced sleep (VIS) leads to increased homeostatic sleep credit and reduced arousability, and can be suppressed by heightened arousal or reduced GABA signaling. Multiple mechanosensory organs mediate VIS, and the magnitude of VIS depends on vibration frequency and genetic background. Sleep induction improves over successive blocks of vibration. Furthermore, training with continuous vibration does not generalize to intermittent vibration, demonstrating stimulus specificity, a characteristic of habituation. Our findings suggest that habituation plays a significant role in sleep induction by vibration.
Objectives
Electrical stimulation of the vestibular system (VeNS) has been shown to improve Insomnia Severity Index (ISI) when delivered during sleep. We hypothesize that repeated electrical vestibular stimulation, when delivered prior to sleep onset, will improve ISI scores. The primary aim of this study was to assess the effect that VeNS had on ISI scores when delivered prior to sleep onset. A secondary aim was to provide initial data indicating “length of time to effect” that will allow more appropriate design of a larger randomized control trial (RCT).
Methods
The present study was an experimental study (pre and post without control). The participants acted as self-controls. After recording the baseline values, electrical vestibular nerve stimulation was administered as intervention once in a day for 30 min, 1 h prior to sleep onset using ML1000 device (Neurovalens, UK) for 14 days.
Results
There was significant decrease in the ISI scores followed by the electrical vestibular nerve stimulation. Further, participants reported a significant increase in well-rested sleep post the intervention period.
Conclusions
This study supports our hypothesis that VeNS has a positive impact on ISI scores when delivered on a regular basis prior to sleep onset.
Objective
Recent research has shown that auditory closed-loop stimulations can enhance sleep slow oscillations (SO) to improve N3 sleep quality and cognition. Previous studies have been conducted in a lab environment and on a small sample size. The present study aimed at validating and assessing the performance of a novel ambulatory wireless dry-EEG device (WDD), for auditory closed-loop stimulations of SO during N3 sleep at home.
Material and Methods
The performance of the WDD to detect N3 sleep automatically and to send auditory closed-loop stimulations on SO were tested on 20 young healthy subjects who slept with both the WDD and a miniaturized polysomnography (part 1) in both stimulated and sham nights within a double blind, randomized and crossover design.
The electrophysiological effects of auditory closed-loop stimulation on delta power increase were assessed after 1 and 10 nights of stimulations on an observational pilot study in the home environment including 90 middle-aged subjects (part 2).
Results
The sensitivity and specificity of the WDD to automatically detect N3 sleep in real-time were 0.70 and 0.90, respectively. The stimulation accuracy of the SO ascending-phase targeting was 45±52°. The stimulation protocol induced an increase of 39.5 % of delta power after the stimulations. The increase of SO response to auditory stimulations remained at the same level after 10 consecutive nights.
Conclusion
The WDD shows good performances to automatically detect in real-time N3 sleep and to send auditory closed-loop stimulations on SO accurately. These stimulations increased the SO amplitude during N3 sleep without any adaptation effect after 10 consecutive nights. This tool provides new perspectives to figure out novel sleep EEG biomarkers in longitudinal studies and can be interesting to conduct broad studies on the effects of auditory stimulations during sleep.
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.
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.
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.
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.
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.
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
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.
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.
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.
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experimental pharmacology, R.H. Adrian,
E. Helmreich, H. Holzer, R. Young, K. Kramer,
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A.E. Renold, et al., eds. (Berlin, Heidelberg, New
York: Springer-Verlag), pp. 1-165.