Duration Of Deep Sleep Research Articles

Enhancement of Sleep Quality and Stability Using Acoustic Stimulation During Slow Wave Sleep

Background: One of the challenges today is that the quality of sleep has weakened by many external factors, which we are not even aware of and which directly affect sleep. Sleep quality has an essential role in maintaining the cognitive function and memory consolidation of individuals. So far, various studies have been done to improve the quality of sleep by using external electrical stimulation, vestibular and olfactory system stimulation. Methods: In this study, the increase in sleep quality was considered by simultaneous acoustic stimulation in a deep sleep to increase the density of slow oscillations. Slow oscillations are the important events recorded in electroencephalography (EEG) and hallmark deep sleep. Acoustic stimulation of pink noise with random frequency ranging from 0.8 to 1.1 Hz was used to improve sleep quality. Results: Eight healthy adults (mean age: 28.4±7.8 years) studied in 3 nights under 3 conditions: accommodation night, stimulation night (STIM) and no stimulation night (SHAM), in counterbalanced order. Significant characteristics of the objective and subjective quality of sleep have been extracted from the acquired EEG and compared in the last 2 nights. Also, the arousal and cyclic alternating pattern characteristics have been measured to assess sleep stability over 2 nights of STIM and SHAM. Conclusion: Our findings confirm this goal of the study that applying designed acoustic stimulation simultaneously in the slow wave sleep (SWS) stage increases the duration of deep sleep and ultimately improves overall sleep stability and quality. Keywords: Sleep quality enhancement; Acoustic stimulation; Slow wave sleep; CAP & arousals; Sleep stability; EEG

Ability of the Fitbit Alta HR to quantify and classify sleep in patients with suspected central disorders of hypersomnolence: A comparison against polysomnography.

Measuring sleep duration and early onset rapid eye movement sleep (REMS) is critical in the assessment of suspected central disorders of hypersomnolence (CDH). Current multi-sensor activity trackers that integrate accelerometry and heart rate are purported to accurately quantify sleep time and REMS; however, their utility in suspected CDH has not been established. This investigation aimed to determine the ability of a current, multi-sensor tracker, Fitbit Alta HR (FBA-HR), to quantify and classify sleep in patients with suspected CDH relative to polysomnography (PSG). Forty-nine patients (46 female; mean age,30.3±9.84years) underwent ad libitum PSG with concurrent use of the FBA-HR. FBA-HR sleep variable quantification was assessed using Bland-Altman analysis. FBA-HR all sleep (AS), light sleep (LS; PSG N1+N2), deep sleep (DS; PSG N3) and REMS classification was evaluated using epoch-by-epoch comparisons. FBA-HR-detected sleep-onset rapid eye movement periods (SOREMPs) were compared against PSG SOMREMPs. FBA-HR displayed significant overestimation of total sleep time (11.6min), sleep efficiency (1.98%) and duration of deep sleep (18.2min). FBA-HR sensitivity and specificity were as follows: AS, 0.96, 0.58; LS, 0.73, 0.72;DS, 0.67, 0.92; REMS, 0.74, 0.93. The device failed to detect any nocturnal SOREMPs. Device performance did not differ appreciably among diagnostic subgroups. These results suggest FBA-HR cannot replace EEG-based measurements of sleep and wake in the diagnostic assessment of suspected CDH, and that improvements in device performance are required prior to adoption in clinical or research settings.

Acute psychosocial stress in mid-aged male rats causes hyperthermia, cognitive decline, and increased deep sleep power, but does not alter deep sleep duration.

Aging is associated with altered sleep architecture and worsened hippocampus-dependent cognition, highly prevalent clinical conditions that detract from quality of life for the elderly. Interestingly, exposure to psychosocial stress causes similar responses in young subjects, suggesting that age itself may act as a stressor. In prior work, we demonstrated that young animals show loss of deep sleep, deficits in cognition, and elevated body temperature after acute stress exposure, whereas aged animals are hyporesponsive on these measures. However, it is unclear if these age-altered stress responses occur in parallel over the course of aging. To address this, here we repeated the experiment in mid-aged animals. We hypothesized that mid-aged stress responses would be intermediate between those of young and aged subjects. Sixteen mid-aged (12months) male F344 rats were implanted with EEG/EMG emitters to monitor sleep architecture and body temperature, and were trained on the Morris water maze for 3 days. On the fourth day, half of the subjects were restrained for 3 hours immediately before the water maze probe trial. Sleep architecture and body temperature were measured during the ensuing inactive period, and on the following day, endpoint measures were taken. Restrained mid-aged animals showed resistance to deep sleep loss, but demonstrated stress-induced water maze probe trial performance deficits as well as postrestraint hyperthermia. Taken in the context of prior work, these data suggest that age-related loss of sleep architecture stress sensitivity may precede both cognitive and body temperature-related stress insensitivity.

Evaluating the Consistency of Current Mainstream Wearable Devices in Health Monitoring: A Comparison Under Free-Living Conditions.

BackgroundWearable devices are gaining increasing market attention; however, the monitoring accuracy and consistency of the devices remains unknown.ObjectiveThe purpose of this study was to assess the consistency of the monitoring measurements of the latest wearable devices in the state of normal activities to provide advice to the industry and support to consumers in making purchasing choices.MethodsTen pieces of representative wearable devices (2 smart watches, 4 smart bracelets of Chinese brands or foreign brands, and 4 mobile phone apps) were selected, and 5 subjects were employed to simultaneously use all the devices and the apps. From these devices, intact health monitoring data were acquired for 5 consecutive days and analyzed on the degree of differences and the relationships of the monitoring measurements ​​by the different devices.ResultsThe daily measurements by the different devices fluctuated greatly, and the coefficient of variation (CV) fluctuated in the range of 2-38% for the number of steps, 5-30% for distance, 19-112% for activity duration, .1-17% for total energy expenditure (EE), 22-100% for activity EE, 2-44% for sleep duration, and 35-117% for deep sleep duration. After integrating the measurement data of 25 days among the devices, the measurements of the number of steps (intraclass correlation coefficient, ICC=.89) and distance (ICC=.84) displayed excellent consistencies, followed by those of activity duration (ICC=.59) and the total EE (ICC=.59) and activity EE (ICC=.57). However, the measurements for sleep duration (ICC=.30) and deep sleep duration (ICC=.27) were poor. For most devices, there was a strong correlation between the number of steps and distance measurements (R2>.95), and for some devices, there was a strong correlation between activity duration measurements and EE measurements (R2>.7). A strong correlation was observed in the measurements of steps, distance and EE from smart watches and mobile phones of the same brand, Apple or Samsung (r>.88).ConclusionsAlthough wearable devices are developing rapidly, the current mainstream devices are only reliable in measuring the number of steps and distance, which can be used as health assessment indicators. However, the measurement consistencies of activity duration, EE, sleep quality, and so on, are still inadequate, which require further investigation and improved algorithms.

Evaluation of depression and quality of life in patients with obstructive sleep apnea syndrome

Sleep fragmentation, repetitive hypoxemia during sleep, excessive sleepiness during the day, lack of concentration, memory loss, depression, decreased libido, and impotence are the characteristics of obstructive sleep apnea syndrome (OSAS) that may impair quality of life (QOL). This study aimed to investigate the QOL and factors that may affect QOL in people with different OSAS severity and without sleep apnea. This was an analytical cross-sectional study. Polysomnography was performed on 200 people. Those detected as having nonapnea and mild-moderate-severe OSAS were administered the Epworth sleepiness scale, Beck Depression Inventory, and the World Health Organization Quality of Life-BREF (WHOQOL-BREF) scale. According to the apnea-hypopnea index, 36 people (18.0%) were in the nonapnea-hypopnea group, 28 (14.0%) in the mild OSAS group, 63 (31.5%) in the moderate OSAS group, and 73 people (36.5%) were in the severe OSAS group. Depression was present in 31 people (15.5%) who participated in the study. The nonapnea-hypopnea group comprised 12.9% of those with depression, mild OSAS group comprised 16.1%, moderate OSAS group comprised 22.6%, and severe OSAS group had 48.4% of the depressed subjects. Beck depression scores showed a significant positive correlation with the Epworth scale (t< 90% SaO2) (r = 0.285, P< 0.001 and r = 0.283, P< 0.001, respectively). The mean scores of WHOQOL-BREF subgroups' physical health (P < 0.001), psychological health (P < 0.001), social relations (P < 0.001), and the environmental area (P < 0.001) in those with depression were statistically significantly lower than those without depression. QOL was significantly associated with the presence of OSAS (P = 0.008). Decreased deep sleep duration, increased arousal index, and a high ratio of sleep duration with oxygen saturation below 90% to the duration of the entire sleep period increase daytime sleepiness and depressive symptoms in those with OSAS; thus, disrupting general health and QOL.

Comparison of the Effects of Attachment Training for Mothers on the Behavioral Responses of Premature Infants: A Randomized Clinical Trial

Background: Premature infants are among high-risk groups in community who need to be hospitalized at intensive care units for survival and receiving basic or special care. Hospitalization at neonatal intensive care units (NICUs) unsettles the family and leads to the separation of parents from their infants. This study aimed to determine the effects of maternal attachment behaviors on the behavioral responses of premature infants, hospitalized at NICUs. Methods: In this randomized clinical trial, 64 premature infants, who were hospitalized at NICUs and were eligible for the study, were randomly allocated to study and control groups. Attachment behaviors including touching, massage and kangaroo care were applied for the study group, while the conventional attachment method was adopted for the control group. Behavioral responses were evaluated two hours before and two hours after training attachment behaviors. Data were analyzed, using Chi-square and student’s t-test. Results: The mean difference in the duration of deep sleep and consciousness was more significant in the study group, compared to the control group. Furthermore, the duration of drowsiness was significantly less in the study group, compared to the control group. Conclusion: The implementation of attachment training at NICUs decreased the time of drowsiness and improved behavioral responses, deep sleep time and consciousness.

Sedative Music Facilitates Deep Sleep in Young Adults

To investigate the effect of sedative music on the different stages of the sleep cycle in young adults with various sleep latencies by using polysomnography (PSG). Prospective, randomized, controlled, crossover study. Sleep center of a teaching hospital. Young adults with different sleep latencies. Poor sleepers (Pittsburgh Sleep Quality Index score ≥5) were excluded. Each participant stayed one night in the sleep center for adaptation and on each of the following two nights was assigned to (1) music and (2) control (without music) conditions in random order. In the music condition, sedative music composed by certified music therapists was played on a compact disc player for the first hour the participant was in bed. Sleep measures recorded with PSG, including sleep latency and durations of sleep stages. Twenty-four young adults (mean±standard deviation, 24.5±2.6 years) participated. They were classified into the short sleep latency (SL) group if the baseline SL of the adaptation night was shorter than 10 minutes or into the long SL group if the baseline SL was 10 minutes or longer. Sedative music did not alter the SL in either group. Sedative music reduced stage II sleep in both SL groups (main effect of music, p=0.03; interaction effect, p=0.87) but increased the duration of deep sleep (stages III and IV) only in the long SL group (main effect of music, p=0.15; interaction effect, p=0.02). In participants with long SL, sedative music improved the quality of sleep by prolonging the duration of deep sleep. This effect provides an alternative and noninvasive way to improve sleep in selected persons experiencing sleep problems.

Nocturnal Enuresis in Children: Prevalence, Correlates, and Relationship with Obstructive Sleep Apnea

To examine the prevalence and correlates of nocturnal enuresis (NE) in primary school children, and to compare the prevalence of NE in children with and those without obstructive sleep apnea (OSA). Parents of children aged 6-11 years completed a questionnaire eliciting information on sleep-related symptoms, demography, and family and past medical history. Children screened due to high risk for OSA, along with a randomly chosen low-risk group, underwent overnight polysomnography (PSG). A total of 6147 children (3032 girls) were studied. The overall prevalence of NE (≥1 wet night/month) was 4.6% (6.7% of boys and 2.5% of girls). Boys had a significantly greater prevalence across all age groups. In 597 children (215 girls) who underwent PSG, the prevalence of NE was not greater in children with OSA, but was increased with increasing severity of OSA in girls only. Boys with NE had longer deep sleep duration. Sex and sleep-related symptoms were associated with NE. This community-based study demonstrated a sex-associated prevalence of NE in relation to increasing OSA severity.

Dynamics of sleep stage transitions in healthy humans and patients with chronic fatigue syndrome.

Physiological and/or pathological implications of the dynamics of sleep stage transitions have not, to date, been investigated. We report detailed duration and transition statistics between sleep stages in healthy subjects and in others with chronic fatigue syndrome (CFS); in addition, we also compare our data with previously published results for rats. Twenty-two healthy females and 22 female patients with CFS, characterized by complaints of unrefreshing sleep, underwent one night of polysomnographic recording. We find that duration of deep sleep (stages III and IV) follows a power-law probability distribution function; in contrast, stage II sleep durations follow a stretched exponential and stage I, and REM sleep durations follow an exponential function. These stage duration distributions show a gradually increasing departure from the exponential form with increasing depth of sleep toward a power-law type distribution for deep sleep, suggesting increasing complexity of regulation of deeper sleep stages. We also find a substantial number of REM to non-REM sleep transitions in humans, while this transition is reported to be virtually nonexistent in rats. The relative frequency of this REM to non-REM sleep transition is significantly lower in CFS patients than in controls, resulting in a significantly greater relative transition frequency of moving from both REM and stage I sleep to awake. Such an alteration in the transition pattern suggests that the normal continuation of sleep in light or REM sleep is disrupted in CFS. We conclude that dynamic transition analysis of sleep stages is useful for elucidating yet-to-be-determined human sleep regulation mechanisms with pathophysiological implications.

Analyzing sleep abnormalities in HIV-infected patients treated with Efavirenz.

Ambulatory electroencephalogram monitoring was performed for 18 HIV-infected subjects treated with efavirenz with and without insomnia and for 13 healthy control subjects. All patients receiving efavirenz had longer sleep latencies and shorter duration of deep sleep, although poor sleepers also showed reduced sleep efficiency and shorter duration of rapid eye movement sleep. Efavirenz plasma levels were higher in patients with insomnia and/or reduced sleep efficiency.

The effect of the terpene fraction of the oil of nutmeg on the behavior of young chicks.

The terpene (i.e. low boiling) fraction of nutmeg oil caused a dose (200–1000 mg/kg, intraperitoneally) dependent increase in the average total duration of light sleep and in the average duration of light sleep episodes in young chicks. In addition, with increasing dose levels, there was an increase in the number of subjects that displayed deep sleep and generally an increase in the average total duration of deep sleep and average duration of deep sleep episodes.

Narcoleptic syndrome and paradoxical sleep.

SummaryIn order to elucidate the mechanism of the narcoleptic syndrome, the course of all‐night sleep was investigated by means of poly graphic methods or by using inducing stimuli. Further study on each symptom was performed in relation to the sleep mechanism using similar methods. Thirty‐three cases of typical narcolepsy were examined. The results from these studies are summarized as follows.1. The paradoxical phase of sleep occurs immediately after sleep onset in the natural nocturnal sleep of narcoleptics. The proportion of sleep time spent in the paradoxical phase (30%) in narcoleptics is higher than in normals, whereas that of the deep sleep stage is lower.2. In narcolepsy, hypnagogic hallucination and sleep paralysis appear mostly during the paradoxical phase. During these episodes the level of cerebral vigilance ascends temporarily but slight differences are found between these two episodes. The responses to the stimuli (auditory evoked response, the H reflex and the knee jerk) are similar to those in normals in each stage of sleep.3. Chlorpromazine, being effective against hypnagogic hallucination and sleep disturbance, stabilizes a night's sleep and prolongs the duration of deep sleep and the paradoxical phase. Imipramine with a suppressing action on cataplectic attack, inhibits the occurrence of the paradoxical phase at sleep onset and diminishes the following paradoxical phases, accompanied by a decrease of hypnagogic hallucination.4. The level of wakefulness tends to descend easily in narcoleptics. In sleep attacks, the subjects fall rapidly into the paradoxical phase from alert or drowsy state. Both sleep attacks and a tendency to fall asleep are apt to occur periodically in the daytime with lucid intervals.5. A cataplectic attack closely relates to the paradoxical phase. During the episode, a great discrepancy is found between hypofunction of the arousal system and function of the motor and autonomic systems. Cataplectic occur frequently concomitant with the sleeping‐waking rhythm.6. Fundamental disorders of narcolepsy are considered as follows: the abnormal occurrence of the paradoxical phase of sleep, the tendency to fall asleep easily, the sleep cycle through night and day and the remarkable dissociation of the arousal system from the motor or autonomic systems. Accordingly, disorders in the sleep‐wakefulness regulating mechanisms are found. Dysfunction of the brain stem reticular formation, especially in the pons, and disturbances of the interrelationship among them are discussed.

Nature of sleep in young infants.

Using criteria of ocular reactions, bodily activity, and respiration in 12 infants up to 6 months of age, four stages of the waking and the sleeping state have been distinguished: 1) deep sleep, as judged by closed eyes, virtual disappearance of bodily activity, regular respiration, and lowered frequency of breathing; 2) sleep with closed eyes, but greater bodily activity and irregularity of respiration; 3) light sleep, or the transitional state between sleep and waking as manifested by alternating open, closed, and half-open eyes, increased activity and frequency of breathing, and irregularity of respiration; 4) the waking state with open eyes, great bodily activity and respiratory frequency, and irregular respiration. This differentiation has enabled more accurate modification of the usually reported observations concerning the shortening of sleep in early life. It is not the duration of deep sleep which decreases, but rather the transitional state between sleep and waking. The waking state significantly lengthens with age. Note: (With the Technical Assistance of V. Lapáccaronková) Submitted on August 14, 1961