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PubMed2004

A comparison of the sleep-wake patterns of cosleeping and solitary-sleeping infants.

This study examined whether 3-15, month-old cosleeping infants displayed differences in time spent in active versus quiet sleep, and in the number/duration of nighttime awakenings when compared with solitary-sleeping infants; and also whether they spent the majority of the night sleeping face-to-face, as previously reported. Nine cosleeping and nine solitary-sleeping infants were matched on age, gender, ethnicity, maternal age, and family SES. Video recordings of nighttime sleep yielded percentage of time in active sleep, quiet sleep, and awake, number of wakenings, and the percentage of time cosleeping infants and mothers spent face-to-face. Across age, cosleeping infants had more awakenings per night mean 5.8(1.50) versus 3.2(1.95); t = 3.16, p = .006). The percent of the nighttime spent awake did not differ between groups, suggesting that cosleeping infants had shorter awakenings. Cosleeping infants spent 40% of the night face-to-face with their mothers.

Adult↗
PubMed2005

Rapid eye movement sleep, non-rapid eye movement sleep, dreams, and hallucinations.

After the discovery of rapid eye movement (REM) sleep in 1953, oneiric activity was long thought to be associated uniquely with REM sleep. Subsequent evaluation of sleep in humans combining neurophysiologic, psychophysiologic, and, more recently, functional neuroimaging investigations, has instead shown that dreaming also occurs during non-REM (NREM) sleep. It has been documented that hallucinatory activity during sleep is a normal phenomenon that is not constant throughout the night but increases toward morning when it tends to become present to the same extent in REM and NREM sleep. The role of sleep mechanisms in the generation of visual hallucinations is well-recognized in narcolepsy in the case of hypnagogic hallucinations, which are thought to derive from a REM-dissociation state in which dream imagery intrudes into wakefulness. Similar mechanisms have been hypothesized to play a role in the physiopathogenesis of visual hallucinations in various neuropsychiatric disorders. Furthermore, a growing body of evidence indicates that not only REM but also NREM processes, such as arousal-related processes, may play a role in the physiopathogenesis of hallucinations in the aforementioned disorders. The role of these processes has been most extensively documented in visual hallucinations occurring in the context of delirium tremens and Parkinson's disease.

Brain↗
PubMed1980

A study of the diagnostic value of waking and sleep EEGs after sleep deprivation in epileptic patients on anticonvulsive therapy.

One hundred and twenty-seven waking and sleep EEGs were recorded from 102 epileptic patients on anticonvulsant therapy, after sleep deprivation. Epileptiform activity was found in 63% of the patients, or 57% of the records. Since in previously recorded waking EEGs epileptic discharges had been registered in 19%, or 17% respectively, the rate of increase was considerable. The rate of activation was 51% in patients without epileptic activity in their waking EEGS. Two-thirds of the epileptiform activity were already recorded in the waking EEGS, after sleep deprivation, One-third was recorded only during sleep. Epileptic discharges in the different sleep stages ranged from 25% (E) to 48% (C). On the other hand, approximately the same frequency was recorded in the separate sleep stages in patients whose waking EEGS after sleep deprivation showed epileptiform activity. The EEG changes were correlated with the different clinical parameters (type of seizure, frequency and duration of seizures, age at the first seizure and the time of examination, neurological findings, and personality changes).

Adolescent↗
PubMed1987

Sleep disorders in kindled cats differ according to the timing of polygraphic recordings and of seizures in the sleep-wake cycle.

Sleep disorders in amygdala-kindled cats differ according to the sleep or waking state in which seizures occur and the time lapse between seizures and polygraphic recordings. Twelve-hour polygraphic recordings were initiated at the following times: (i) before kindling (N = 8 cats); (ii) just after kindled convulsions during waking, slow-wave sleep (SWS), rapid-eye-movement sleep (REMS), or in transition from SWS to REMS (N = 8 cats per state), and (iii) 24 h after state-specific seizures (N = 8 cats per state). Rapid onset SWS and delayed REMS occurred in records started immediately after seizures in waking, SWS, or REMS; in contrast, seizures during transitions from SWS to REMS produced early onset REMS and SWS. Finally, records begun 24 h after seizures always revealed prolonged sleep onset and generalized sleep suppression regardless of the state in which seizures occurred. The timing of seizures and of polygraphic recordings may explain discrepancies in the literature on the type of sleep disorders seen in secondary generalized temporal lobe epilepsy.

Animals↗
PubMed1988

The sequential hypothesis on sleep function. I. Evidence that the structure of sleep depends on the nature of the previous waking experience.

The sequential hypothesis on sleep function assumes that the information gathered by brain during the waking period is processed during sleep in two main steps occurring during synchronized sleep (SS) and, eventually, during paradoxical sleep (PS). To verify the main consequences of the hypothesis, i.e., (1) that SS is involved in brain information processing; and (2) that the structure of sleep is dependent on the nature of the previous waking experience, an experiment was designed involving rats exposed to a training session (two-way active avoidance) but failing to learn (NL), and rats left in their home cages in the same training room (C). The structure of sleep, determined by EEG techniques in the postacquisition period (3 hr), was different in NL rats in comparison to C rats, chiefly because SS episodes were markedly longer in the former group. A more detailed analysis indicated that, in NL rats, SS episodes not followed by PS increased their duration first, while those followed by PS became longer in the second half of the sleep period. Comparable results were obtained in the comparison of NL and C subgroups deprived of PS at the end of the acquisition period by chlomipramine treatment. The data support the sequential hypothesis and provide evidence for a primary role of SS in brain information processing.

Animals↗
PubMed1992

The sequential hypothesis of sleep function. IV. A correlative analysis of sleep variables in learning and nonlearning rats.

Female adult rats were trained for a two-way active avoidance task (4 h), and allowed free sleep (3 h). Control rats (C) were left in their home cages during the acquisition period. Dural electrodes and an intraventricular cannula, implanted one week in advance, were used for EEG recording during the period of sleep and for the injection of [3H]thymidine at the beginning of the training session, respectively. Rats were killed at the end of the sleep period, and the DNA-specific activity was determined in the main brain regions and in liver. Correlations among sleep, behavioral and biochemical variables were assessed using Spearman's nonparametric method. In learning rats (L), the number of avoidances was negatively correlated with SS-W variables, and positively correlated with SS-PS variables (episodes of synchronized sleep followed by wakefulness or paradoxical sleep, respectively) and with PS variables. An inverse pattern of correlations was shown by the number of escapes or freezings. No correlations occurred in rats unable to achieve the learning criterion (NL). In L rats, the specific activity of brain DNA was negatively correlated with SS-W variables and positively correlated with SS-PS variables, while essentially no correlation concerned PS variables. On the other hand, in NL rats, comparable correlations were positive with SS-W variables and negative with SS-PS and PS variables. Few and weak correlations occurred in C rats. The data support a role of SS in brain information processing, as postulated by the sequential hypothesis on the function of sleep. In addition, they suggest that the elimination of nonadaptive memory traces may require several SS-W episodes and a terminal SS-PS episode. During PS episodes, adaptive memory traces cleared of nonadaptive components may be copied in more suitable brain sites.

Animals↗
PubMed1994

Paradoxical timing of the circadian rhythm of sleep propensity serves to consolidate sleep and wakefulness in humans.

The contribution of the circadian pacemaker and the sleep homeostat to sleep tendency and consolidation was quantified by forced desynchrony of the sleep-wake cycle from the circadian pacemaker in eight men who lived in time-isolation for 33-36 days. Analysis of 175 polygraphically recorded sleep episodes revealed that the circadian pacemaker and the sleep homeostat contribute about equally to sleep consolidation, and that the phase relationship between these oscillatory processes during entrainment to the 24-h day is uniquely timed to facilitate the ability to maintain a consolidated bout of sleep at night and a consolidated bout of wakefulness throughout the day.

Adult↗
PubMed2005

The association of tongue scalloping with obstructive sleep apnea and related sleep pathology.

OBJECTIVE: The association between OSAS and patient history and physical exam findings is previously established; however, to our knowledge there are no studies that evaluate the role of tongue scalloping as a reliable clinical indicator for OSA, snoring, or the presence of other sleep pathology as evidenced by polysomnography. This study evaluates the hypothesis that such an association exists. SUBJECTS AND METHODS: Sixty-one otolaryngology clinic patients were evaluated by history and physical exam for the presence and degree of tongue scalloping, snoring, and other previously established clinical indicators for sleep-disordered breathing and obstructive apnea. Twenty-five of the 61 study patients were additionally evaluated by overnight polysomnography to provide conclusive diagnosis of sleep pathology. The degree of tongue scalloping was graded from 0 to 3 and its significance as a screening, diagnostic, and predictive factor for sleep pathology was then statistically determined. RESULTS: Twenty-seven patients (44%) had known or newly documented OSA and 47 (77%) had a history of snoring. Twenty-seven patients (44%) had some degree of tongue scalloping (1-3) and 74% of these patients were male. The presence of any degree of tongue scalloping (grade 1-3) in patients with known or newly documented OSA showed sensitivity, specificity, PPV, and NPV of 52%, 68%, 70%, and 50% respectively. The presence of tongue scalloping in patients with either known snoring history or newly documented snoring showed sensitivity, specificity, PPV, and NPV of 47%, 64%, 81%, and 26% respectively. Presence of tongue scalloping was 71% specific for abnormal sleep efficiency (<85%), 70% specific for abnormal AHI (>5), and 86% specific for nocturnal desaturation >4% below baseline. Presence of tongue scalloping also showed PPV of 67% for abnormal AHI, 89% for apnea or hypopnea, and 89% for nocturnal desaturation. Presence and severity of tongue scalloping showed positive correlation with increasing Mallampati and modified Mallampati airway classification. CONCLUSIONS: In high-risk patients we found tongue scalloping to be predictive of sleep pathology. Tongue scalloping was also associated with pathologic polysomnography data and abnormal Mallampati grades. We feel the finding of tongue scalloping is a useful clinical indicator of sleep pathology and that its presence should prompt the physician to inquire about snoring history.

Adult↗
PubMed2000

Relations among hypoxemia, sleep stage, and bradyarrhythmia during obstructive sleep apnea.

BACKGROUND: Obesity, apneic hypoxemia, and rapid eye movement (REM) sleep are supposed to be the major causes for bradyarrhythmia in patients with obstructive sleep apnea. The aims of this study were to compare clinical findings and diagnoses in patients with obstructive sleep apnea with and without nocturnal bradyarrhythmia and to analyze the relations among hypoxemia, sleep stage, and bradyarrhythmia. METHODS: During a 17-month period 239 patients were found to have sleep apnea in an ambulatory study. Patients with nocturnal bradyarrhythmia were hospitalized for 3 days and polysomnographies were performed over 2 successive nights. A Holter electrocardiogram was recorded for 48 hours. RESULTS: Nocturnal episodes of bradyarrhythmia were identified in 17 (7%) of 239 patients. Body mass index (39 +/- 7 vs 31 +/- 5 kg/m(2)) and respiratory disturbance index (90 +/- 36 per hour vs 24 +/- 24 per hour) were significantly different (P <.01) between patients with (n = 17) and without bradyarrhythmia (n = 222). Bradyarrhythmia occurred significantly more often during REM than non-REM sleep (P <.01). There was a significant difference in end-apneic oxygen saturation in apnea/hypopnea episodes with and without bradyarrhythmia (71% +/- 9% vs 75% +/- 10%; P <.01). A linear relation between end-apneic oxygen saturation and number of sinus arrests and heart blocks could not be found. CONCLUSIONS: Patients with apnea-associated bradyarrhythmia are more overweight than patients without bradyarrhythmia. The higher respiratory disturbance index measurements found in these patients may be caused by this difference. Bradyarrhythmia occurs predominantly during REM sleep and occurred independently from decrease in oxygen saturation; a threshold value as an upper limit could not be found.

Adolescent↗
PubMed1999

Sleep-disordered breathing and periodic limb movements in sleep in older patients with schizophrenia.

BACKGROUND: Since the prevalence of both sleep-disordered breathing (SDB) and periodic limb movements in sleep (PLMS) increase with age, we explored whether older schizophrenia patients would have a high incidence of SDB and PLMS. Correlations between sleep and clinical variables were also examined. METHODS: Fifty-two patients (mean age = 59.6 years, SD = 8.9) had their sleep/wake, respiration, and leg movements recorded using a modified Medilog/Respitrace portable recording system plus oximetry. A battery of clinical, psychosocial, and motor disturbance variables were collected by research center staff. RESULTS: Forty-eight percent of these patients had at least 10 respiratory events per hour of sleep. These patients reported more symptoms of daytime sleepiness than patients with fewer than 10 events per hour. The relatively high prevalence of SDB in this group may contribute to overall sleep disturbances, and does not appear to be a result of high body mass index. Only 14% of the patients had at least five limb movements per hour of sleep, suggesting the prevalence of PLMS is much lower than expected in this age group. The number of leg jerks was inversely related to symptoms of tardive dyskinesia. CONCLUSIONS: The disturbance of sleep in these patients may be due, in part, to SDB, but is unlikely due to PLMS.

Age Factors↗
PubMed1996

Role of the locus coeruleus in the sleep rebound following two different sleep deprivation methods in the rat.

The aim of the present study was to assess the involvement of the locus coeruleus in the paradoxical sleep rebound following sleep deprivation in the rat. Animals were sleep-deprived for 10 h before, and after, specific N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) lesioning of the noradrenergic-locus coeruleus system. Sleep deprivation was produced using either an instrumental (water tank) or pharmacological (methylamphetamine) method. After lesioning, the rats submitted to the instrumental method showed a significant decrease in the paradoxical and slow-wave sleep rebounds (-54% and -78%, respectively), while animals receiving metamphetamine did not. Our results suggest that the noradrenergic system of the locus coeruleus is a relevant component of the sleep rebound mechanisms. However, the extent of involvement is dependent on the sleep deprivation method used.

Adrenergic Agents↗
PubMedDate not supplied

Sleep breathing and sleep movement disorders masquerading as insomnia in sexual-assault survivors.

A descriptive, hypothesis-generating study was performed with 156 female sexual-assault survivors who suffered from insomnia, nightmares, and posttraumatic stress disorder (PTSD). They completed 2 self-report sleep questionnaires to assess the potential presence of intrinsic sleep disorders. Seventy-seven percent of the sample (120 of 156) endorsed additional sleep complaints, besides their insomnia symptoms, that indicate the potential presence of sleep-disordered breathing ([SDB] 81 of 156, 52%) and sleep-related movement disorders ([SMD] 94 of 156, 60%). The potential for SDB was strongly correlated with the body mass index (BMI), an increase in arousal symptoms, and greater total PTSD severity. In some sexual-assault survivors, the relationship between sleeplessness and posttraumatic stress may be caused or exacerbated by intrinsic sleep disorders, and not be solely a function of psychophysiological insomnia--the traditional diagnostic term usually offered to explain the sleep problems associated with PTSD. Prevalence studies that use objective diagnostic evaluations such as polysomnography (PSG) are needed to test these hypotheses.

Adolescent↗
PubMedDate not supplied

Delta sleep ratio as a predictor of sleep deprivation response in major depression.

The fast but short-lasting improvement of depressive symptoms by sleep deprivation (SD) in about 60% of patients with a major depressive disorder is well established, but the mechanisms of action are still not clear. Recent studies suggest that changes in non rapid eye movement (NREM) sleep, especially in slow wave activity (SWA), could be associated with the therapeutic outcome of SD. In the current study, spectral analysis of NREM sleep EEG directly prior to SD was performed to determine if automatically derived sleep parameters predict SD response. Sixteen pair matched and drug free patients with a major depressive disorder, 8 SD responders and 8 non-responders (response criterion: 50% reduction on the 6-item HAMD score), were included. Average EEG spectral power was calculated for the whole night before SD and for single NREM episodes. While whole-night averages of spectral power did not differ significantly between subgroups, SD responders showed a steady decrease of SWA across successive NREM episodes, whereas in non-responders an increase from the first to the second episode was observed. The different distribution of SWA was significantly expressed in the delta sleep ratio (quotient of SWA in the first to the second NREM episode). In conclusion, a high delta sleep ratio is a positive predictor for SD response. Referred to psycho- and pharmacotherapeutic results it is hypothesized that low and high values of the delta sleep ratio characterize subgroups of depressed patients with different neurobiological alterations, which could be relevant for further scientific and therapeutic approaches.

Adult↗
PubMed2002

Comparison of the effects of modafinil and sleep deprivation on sleep and cortical EEG spectra in mice.

Modafinil is a wakefulness-promoting substance whose profile differs from that of the classical psychostimulants. It is still unknown whether waking induced by modafinil and wakefulness induced by sleep deprivation differ in terms of their effect on subsequent sleep. To investigate this problem sleep was recorded in two groups of OF1 mice. One group received modafinil (200 mg/kg, i.p.) at light onset which induced a period of wakefulness of approx. 5 h, while animals of the subsequent control group were injected with vehicle and kept awake for an equivalent duration. The effect of the two treatments on sleep was similar. REM sleep was initially reduced and slow-wave activity (SWA; EEG power in the 0.75-4.0 Hz range) in nonREM sleep was enhanced for several hours. The SWA increase was more prominent over the frontal cortex than over the occipital cortex after both treatments. A minor difference was seen at the occipital site where the initial rise of power in the low-frequency range was larger after vehicle combined with enforced waking than after modafinil. The study shows that the homeostatic sleep response following the modafinil-induced wakefulness corresponds largely to the response following a non-pharmacologically induced extended waking episode.

Analysis of Variance↗
PubMed2000

Psychometric assessment of subjective sleep quality using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) in psychiatric disordered and control subjects.

Subjective sleep quality has been identified as an important clinical construct in psychiatric disordered patients. The Pittsburgh Sleep Quality Index (PSQI), one of the most widely used standardized measures to assess subjective sleep quality, generates a global score and scores seven components. The present study psychometrically assessed clinical profiles of subjective sleep quality in 82 control and 92 psychiatric disordered subjects (primary insomnia, n=14; major depression, n=30; generalized anxiety disorder, n=24; and schizophrenia, n=24), using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J). The overall reliability coefficient of the PSQI-J was high (Cronbach's alpha=0.77). Correlation coefficients between the PSQI-J global and component scores were statistically significant. The PSQI-J global and component mean scores were significantly higher in psychiatric disordered subjects than control subjects, except for the component of sleep duration. Using a cut-off point of 5.5 in the PSQI-J global score, estimations of sensitivity and specificity provided 85.7 and 86.6% for primary insomnia, 80.0 and 86.6% for major depression, 83.3 and 86.6% for generalized anxiety disorder, and 83.3 and 86.6% for schizophrenia, respectively. The present study supports the utility of the PSQI-J as a reliable and valid measure for subjective sleep quality in clinical practice and research.

Adult↗
PubMed1984

Uridine as an active component of sleep-promoting substance: its effects on nocturnal sleep in rats.

A 10-h intraventricular infusion of 10 pmol of uridine from 19.00 to 05.00 h resulted in significant increases in sleep in otherwise saline-infused male rats (n = 8) during the environmental dark period (20.00-08.00 h). Increments of slow wave sleep (SWS) and paradoxical sleep (PS) were 21.0% and 68.1%, respectively, of the baseline value. This was due to increases in the frequencies of both SWS and PS episodes but not to their durations. Similar increases occurred the first recovery night under saline infusion, but sleep amounts returned to the baseline levels the second night. Brain temperature was not affected by uridine administration. A small dose of uridine (1 pmol/10 h) exerted no effect (n = 6) while larger doses (100 and 1000 pmol/10 h, each n = 5) resulted in slight but insignificant increases in SWS and PS. The 1000-pmol uridine administration seemed to be non-physiological since it brought about irregularities in locomotor activity and sleep-waking rhythms. Thus, authentic uridine exhibited the same sleep-enhancing effects as a naturally occurring active component of sleep-promoting substance, which was recently identified with uridine.

Animals↗
PubMedDate not supplied

Aging does not affect the sleep endocrine response to total sleep deprivation in humans.

Aging is associated with decreased sleep continuity, slow wave sleep (SWS), growth hormone (GH) release and an increased hypothalamo-pituitary-adrenocortical (HPA) system activity. Total sleep deprivation (TSD) is a strong stimulus for sleep. To determine if aging affects the response to TSD, for the first time the combined effects of TSD on conventional and spectral sleep electroencephalographic (EEG) parameters and GH, cortisol and prolactin secretion were compared in elderly (60-80 years; n = 7) vs. younger subjects (20-30 years; n = 7). MANOVA revealed a reduction of SWS in the elderly. TSD led to an increase in SWS, a decrease in sleep onset latency, rapid eye movement (REM) density and by trend REM-latency without a global group difference. GH was reduced, whereas prolactin was enhanced in the elderly. After TSD GH was unchanged and prolactin secretion was enhanced without group difference. Thus, the plasticity of the sleep-endocrine system in response to TSD is sustained during aging. The possible involvement of the GABAergic system, that seems not to be severely impaired with age, is proposed.

Adult↗
PubMed2002

Sleep, the hypothalamic-pituitary-adrenal axis, and cytokines: multiple interactions and disturbances in sleep disorders.

Sleep is an important component of mammalian homeostasis, vital for survival. Sleep disorders are common in the general population and are associated with significant medical, psychologic, and social disturbances. Sleep, in particular deep sleep, has an inhibitory influence on the HPA axis, whereas activation of the HPA axis or administration of glucocorticoids can lead to arousal and sleeplessness. Insomnia, the most common sleep disorder, is associated with a 24-hour increase of ACTH and cortisol secretion, consistent with a disorder of central nervous system hyperarousal. Sleepiness and fatigue are very prevalent in the general population, and recent studies have demonstrated that the proinflammatory cytokines IL-6 and/or TNF-alpha are elevated in disorders associated with excessive daytime sleepiness, such as sleep apnea, narcolepsy, and idiopathic hypersomnia. Sleep deprivation leads to sleepiness and daytime hypersecretion of IL-6. Combined, these findings suggest that the HPA axis stimulates arousal, while IL-6 and TNF-alpha are possible mediators of excessive daytime sleepiness in humans.

Adrenal Glands↗