non-REM Period Research Articles

Association of sleep disorders with clinical symptoms and age in Chinese older adult patients with and without cognitive decline.

To investigate correlation between cognitive function, age, and sleep disturbances. This retrospective clinical study enrolled 78 patients with sleep disorders who were divided into three groups: a group of 24 patients with sleep disorders accompanied by cognitive decline (SD-CD); 54 patients with sleep disorders and no cognitive decline (SD-nCD) was divided into two groups, one of 30 patients aged between 60 and 70 years and another of 24 patients aged >70 years. Polysomnography was used to record patients' sleep indicators throughout night; these included total sleep duration, sleep efficiency (SE), sleep latency, sleep structure and percentage of N1, N2, and N3 stages, rapid eye movement (REM) stage, as well as apnea hypopnea index (AHI), and oxygen saturation (OS). Analysis of variance (ANOVA) for continuous variables and chi-square test for categorical variables were used to analyze variables between different groups. Pearson's correlation was used to analyze correlation between sleep parameters and mini-mental state examination (MMSE). Blood samples were used to determine their Aβ, Aβ40, Aβ42, total tau, phosphorylated tau protein (ptau), ptau181, ptau217, the inflammatory factor IL-1β, vitamin B12 (VB12), and melatonin levels. In the SD-CD group, there was a significant decrease in SE and an increase in N1 stage sleep in older patients and a significant increase in AHI, REM stage AHI, and non-REM stage AHI. In patients with SD-nCD, the minimum OS, minimum OS in the REM period, and minimum OS in the non-REM period were significantly reduced. OS was significantly correlated with cognitive level, as evaluated by the MMSE. The addition of sleep parameters can significantly improve the accuracy of dementia diagnosis. Dementia biomarkers of Aβ and tau proteins in blood showed cognition-related differences, while ptau181 was associated with both cognition and age-related differences. Regression models revealed that age was related to higher levels of cognitive decline before (β = -0.43, P < 0.001) and after (β = -0.38, P < 0.001) adjustment of gender, BMI, and education level. There was a significant mediation effect of relationship between aging and cognitive function by sleep efficiency and N1 stage sleep. Sleep disorders and low OS are associated with a higher incidence of cognitive decline and dementia.

Associations among sleep-disordered breathing, arousal response, and risk of mild cognitive impairment in a northern Taiwan population.

Dementia is associated with sleep disorders. However, the relationship between dementia and sleep arousal remains unclear. This study explored the associations among sleep parameters, arousal responses, and risk of mild cognitive impairment (MCI). Participants with the chief complaints of memory problems and sleep disorders, from the sleep center database of Taipei Medical University Shuang-Ho Hospital, were screened, and the parameters related to the Cognitive Abilities Screening Instrument, Clinical Dementia Rating, and polysomnography were determined. All examinations were conducted within 6 months and without a particular order. The participants were divided into those without cognitive impairment (Clinical Dementia Rating = 0) and those with MCI (Clinical Dementia Rating = 0.5). Mean comparison, linear regression models, and logistic regression models were employed to investigate the associations among obtained variables. This study included 31 participants without MCI and 37 with MCI (17 with amnestic MCI, 20 with multidomain MCI). Patients with MCI had significantly higher mean values of the spontaneous arousal index and spontaneous arousal index in the non-rapid eye movement stage than those without MCI. An increased risk of MCI was significantly associated with increased spontaneous arousal index and spontaneous arousal index in the non-rapid eye movement stage with various adjustments. Significant associations between the Cognitive Abilities Screening Instrument scores and the oximetry parameters and sleep disorder indexes were observed. Repetitive respiratory events with hypoxia were associated with cognitive dysfunction. Spontaneous arousal, especially in non-rapid eye movement sleep, was related to the risk of MCI. However, additional longitudinal studies are required to confirm their causality. Tsai C-Y, Hsu W-H, Lin Y-T, etal. Associations among sleep-disordered breathing, arousal response, and risk of mild cognitive impairment in a northern Taiwan population. J Clin Sleep Med. 2022;18(4): 1003-1012.

Clinical features of obstructive sleep apnea in children with obesity.

To study the clinical features of obstructive sleep apnea (OSA) in children with obesity. A retrospective analysis was performed on the medical data of 33 obese children aged 7-15 years, who were diagnosed with OSA and received polysomnography (PSG) in the Department of Respiratory Medicine in Shenzhen Children's Hospital. Fifty OSA children with normal body weight, matched for sex and age, were enrolled as the control group. Among the 33 obese children with OSA, the three most common daytime symptoms were inattention in 30 children (91%), somnolence in 22 children (67%), and morning fatigue in 21 children (64%), and the three most common nocturnal symptoms were snoring in 27 children (82%), mouth breathing in 20 children (61%), and sweating in 16 children (49%). Compared with the reference values of normal children, both the OSA + obesity group and the control group had prolonged light sleep, shortened deep sleep, and a significantly shortened rapid eye movement (REM) period, while there was no significant difference in these indices between the two groups (P>0.05). The apnea-hypopnea index, obstructive apnea/hypopnea index, and oxygen desaturation index in both REM and non-REM periods in the OSA +obesity group were significantly higher than those in the control group (P<0.05), while the lowest blood oxygen saturation during sleep was significantly lower in the OSA + obesity group (P<0.05). The children with obesity and OSA have the main daytime symptoms of inattention, somnolence, and morning fatigue and the main nocturnal symptoms of snoring, mouth breathing, and sweating. There is no significant difference in sleep structure between OSA children with obesity and those with normal body weight; however, respiratory events and blood oxygen saturation decline are more severe in OSA children with obesity. Citation.

Destabilization of light NREM sleep by thalamic PLC\u03b24 deletion impairs sleep-dependent memory consolidation

Sleep abnormality often accompanies the impairment of cognitive function. Both rapid eye movement (REM) and non-REM (NREM) sleep have associated with improved memory performance. However, the role of composition in NREM sleep, consisting of light and deep NREM, for memory formation is not fully understood. We investigated how the dynamics of NREM sleep states influence memory consolidation. Thalamocortical (TC) neuron-specific phospholipase C β4 (PLCβ4) knockout (KO) increased the total duration of NREM sleep, consisting of destabilized light NREM and stabilized deep NREM. Surprisingly, the longer NREM sleep did not improve memory consolidation but rather impaired it in TC-specific PLCβ4 KO mice. Memory function was positively correlated with the stability of light NREM and spindle activity occurring in maintained light NREM period. Our study suggests that a single molecule, PLCβ4, in TC neurons is critical for tuning the NREM sleep states and thus affects sleep-dependent memory formation.

Stilbene Glucoside, a Putative Sleep Promoting Constituent from Polygonum multiflorum Affects Sleep Homeostasis by Affecting the Activities of Lactate Dehydrogenase and Salivary Alpha Amylase.

Chinese herbal medicine (CHM) has been used for treating insomnia for centuries. The most used CHM for insomnia was Polygonum multiflorum. However, the molecular mechanism for CHM preventing insomnia is unknown. Stilbene glucoside (THSG), an important active component of P. multiflorum, may play an important role for treating insomnia. To test the hypothesis, Kunming mice were treated with different dosages of THSG. To examine the sleep duration, a computer-controlled sleep-wake detection system was implemented. Electroencephalogram (EEG) and electromyogram (EMG) electrodes were implanted to determine sleep-wake state. RT-PCR and Western blot was used to measure the levels of lactate dehydrogenase (LDH) and saliva alpha amylase. Spearman's rank correlation coefficient was used to identify the strength of correlation between the variables. The results showed that THSG significantly prolonged the sleep time of the mice (p<0.01). THSG changed sleep profile by reducing wake and rapid eye movement (REM) period, and increasing non-REM period. RT-PCR and Western blot analysis showed that THSG could down-regulate the levels of LDH and saliva alpha amylase (p<0.05). The level of lactate and glucose was positively related with the activity of LDH and saliva alpha amylase (p<0.05), respectively. On the other hand, the activities of LDH and amylase were negatively associated with sleep duration (p<0.05). The levels of lactate and glucose affect sleep homeostasis. Thus, THSG may prevent insomnia by regulating sleep duration via LDH and salivary alpha amylase.

ID 84 – EEG monitoring of sleep is important in the detection of dementia-associated epilepsy

Objective Major neurocognitive disorders represent a huge medical and social challenge. Neurocognitive disorders, especially Alzheimer’s disease (AD) are frequently associated with epilepsy. Epileptic seizures and interictal epileptic activity have important impact on the cognitive performance of AD patients and on the progression of the disease. Accurate detection of epilepsy is difficult in AD. Methods In the framework of Alzheimer–Epilepsy Project of the National Brain Research Program of Hungary (KTIA_NAP_13-1-2013-0001), we performed 48 h-long EEG monitoring in 5 AD patients suffering from epilepsy. We analyzed the distribution of occurrence of ictal and interictal epileptiform EEG activity during wakefulness, non-REM sleep and REM sleep. Results We found significantly higher preponderance of epileptiform EEG discharges during non-REM sleep periods compared to wakefulness. The sleep pattern of all patients was severely disturbed. Conclusions Long-term EEG with sleep studies appear necessary for the correct diagnosis of epilepsy in AD. We assume that epileptiform activity in slow-wave sleep as well as the disruption of the physiologic sleep pattern may have an impact on the impaired memory functions in AD. Further investigations are required to enlighten this important association. Key message EEG monitoring of sleep is necessary for the accurate diagnosis of dementia-associated epilepsy.

Cold exposure and/or fasting modulate the relationship between sleep and body temperature rhythms in mice

We assessed the relationship between core temperature (Tc) and sleep rhythms in mice, and examined the effects of ambient temperature and fasting. Tc, electroencephalograms (EEG), electromyograms (EMG), and spontaneous activity in male ICR mice (n=9) were measured by telemetry for 3days under a 12:12h dark–light cycle. Mice were fed or fasted at an ambient temperature (Ta) of 27°C or 20°C for the final 30h of the experiment. The vigilance state was categorized into a wake state, rapid-eye movement (REM) sleep, and non-REM (NREM) sleep, and the total sleep time (TST) was assessed. Relationships between Tc and TST, NREM periods, and REM sleep were estimated using Pearson's correlation coefficient. During cold exposure, Tc decreased during the dark and light phases, and TST and the periods of NREM and REM sleep decreased during the dark phase. Throughout the fasting period, Tc also decreased during the dark and light phases. Furthermore, the decrease in Tc was augmented when fasting and cold were combined. TST and NREM sleep periods decreased in the light and dark phases, respectively, whereas REM sleep periods decreased in both phases. Negative linear correlations (r=−0.884 to −0.987) were observed between Tc and TST, NREM sleep periods, and REM sleep periods, except for Tc and REM sleep periods where fasting and cold conditions were combined. The correlations between sleep and Tc rhythms were well maintained during cold exposure and fasting. However, when cold and fasting were combined, REM sleep and Tc rhythms were desynchronized.

Withdrawal of anti-epileptic medications during video EEG monitoring does not alter ECG parameters or HRV

To assess if anti-epileptic drug (AED) withdrawal/cessation results in changes in ECG parameters and/or measures of heart rate variability (HRV), in patients having VEEG monitoring, that might affect susceptibility to sudden death in epilepsy. In this study, we included 36 patients with medically refractory epilepsy undergoing continuous video-EEG-ECG monitoring in hospital for pre-surgical assessment. We recorded and analysed multiple 10-min epochs of 2-lead ECG during periods when the subjects were awake and in REM and non-REM sleep, both on admission, and after the subjects had been partially or completely weaned from their AEDs. We compared ECG parameters and measures of HRV from these recorded epochs before and after AED reduction/cessation, with each patient acting as their own comparator. Epochs measured during awake, REM, and non-REM periods were analysed separately. In addition, we analysed a subgroup of patients who had been withdrawn from Na+-channel blocking medications specifically, to analyse the effect of this particular class of AEDs in isolation. Upon AED withdrawal, we observed a small increase in heart rate and shortening of the QT interval, when subjects were awake, but no other changes in ECG parameters were detected, nor did we find changes in any measure of HRV. In addition, no significant changes were found during sleep. Similar results were found in the analysis of the subgroup of patients withdrawn from Na+-channel blocking AEDs. Our study does not support a prominent role for AEDs, and withdrawal/cessation of AEDs, in deranging cardiac physiology during video EEG monitoring in medically refractory epilepsy patients undergoing video EEG monitoring.

Mood disorders in the light of genes, comorbidity and contemporary treatment

The Author(s) 2011. This article is published with open access at Springerlink.com Affective disorders like depression rank worldwide among the most disabling in terms of WHO global burden of disease, are socioeconomically relevant, severe and prevalent. Due to persisting cognitive symptoms, these diseases lead to enormous social disabilities and they dramatically increase the risk of suicide. A genetic influence and the serotonin transporter (5HTT) play a major role in the pathophysiology of mood disorders and suicidal behavior. Pinto et al. [1] investigated the effect of genomic imprinting of the four 5HTT genetic markers and expression of 5HTT alleles in lymphocytes of suicide attempters and 312 nuclear families with at least one member affected by bipolar disorder. Allele 2651T was transmitted more often to bipolar patients, but the authors did not find differential gene expression between bipolar suicide attempters and non-attempters, which does not support a role for allelic expression of 5HTT in suicidal behavior. Due to the high risk of suicide and social disabilities despite antidepressant medication, add-on therapy entailing fewer side effects should be investigated. Tajalizadekhoob et al. [2] applied fish oil capsules containing polyunsaturated fatty acids (PUFAs) in elderly patients with mild to moderate depression as add-on therapy during a period of six months. Treatment with PUFAs showed significant effects compared to placebo and may be beneficial in depressed elderly patients who are at greater risk for cardiovascular diseases. In fact, major depression is associated with increased volumes of visceral fat and high prevalence of the metabolic syndrome, leading to coronary artery disease. Greggersen et al. [3] investigated visceral fat content in young depressed women with and without comorbid borderline personality disorder. They found a significant increase in visceral fat content in major depression, but no additional effects of borderline personality disorder, which does not seem to be an additive risk factor for the metabolic syndrome. Sleep disturbances are common in both depressed and alcohol-dependent patients, including decreased slow wave sleeps (SWS). Brower et al. [4] compared power spectral analysis of polysomnography recordings in men with alcohol dependence compared to subjects with major depression. Both groups showed blunted slow wave activities: men with major depression showed the least slow wave activities in the first non-REM period, whereas men with alcohol dependence had the slowest slow wave activity decay rate. New treatment approaches should selectively improve these different components of sleep homeostasis. In a study by Cordes et al. [5], antidepressant therapy with clomipramine has shown to induce a significant increase in serum prolactin levels in women, but not in men with major depression, indicating effects of clomipramine on the central monoaminergic system. In line with a glutamate hypothesis of depression, the N-methyl-Daspartate (NMDA) receptor antagonist ketamine has been shown to be therapeutically effective in unipolar and bipolar depression. In a retrospective chart analysis of Kranaster et al. [6], effects of ketamine as anesthetic during electroconvulsive therapy (ECT) in patients with therapyresistant depression have been compared to anesthesia with the barbiturate thiopental. Interestingly, the ketamine group

Birinci Basamakta Uyku Bozukluklarına Yaklaşım ve Öneriler

In this review, it was explained to primary care approach to sleep disorders. Sleep is a temporary unconsicious period and has REM and NonREM periods. The major neurotransmitter of REM is acetylcholine and of NonREM are GABA and serotonine. Sleep disorders can be divided in three groups according to occurence period: (1) Sleep disorders seen in REM, (2) in NREM and (3) in any of REM or NonREM periods. Patients with sleep disorders may exhibit life threatening effects (road and work accidents), social maladjustment, decreased academic and occupational performance. Thus, sleep disorder is a serious condition that requires investigation, diagnosis and treatment. As with most medical condition, evaluation of sleep disorders begins a precise history.

Sleep and Active Renin Levels – Interaction with Age, Gender, Growth Hormone and Cortisol

Aims: In young normal male subjects, plasma renin activity (PRA) shows large oscillations with a distinct association to the cyclic occurrence of rapid eye movement (REM) and non-REM (NREM) periods. Until now the sleep-related course of active renin levels is unknown. Furthermore, there are no data on the effects of age and gender on nocturnal renin and the interaction between these variables, sleep, growth hormone (GH) and cortisol. Methods: We investigated simultaneously sleep EEG (23:00–07:00 h) and the plasma concentrations (23:00–07:00 h) of active renin (in 10-min intervals) and of GH and cortisol (in 20-min intervals) in 47 healthy volunteers (24 women and 23 men) aged 19–69 years. Results: In the total sample, significant positive correlations were found between renin concentrations and NREM sleep and the sleep efficiency index, whereas a significant negative correlation exists to wakefulness. Renin shows also a positive correlation to GH levels which is restricted to the younger subjects (<40 years) during NREM sleep. No association exists between renin and cortisol. The averaged nocturnal mean renin levels were significantly lower in female than in male subjects, and in subjects older than 40 years than in younger subjects. Oscillations of active renin levels were found with increases during NREM periods and decreases during REM periods. Conclusions: In all, nocturnal averaged renin levels are lower in women than in men, decrease during ageing and correlate positively with GH, whereas the interaction between renin and sleep is independent from age and gender.

MEG identifies dorsal medial brain activations during sleep

All sleep stages contain epochs with high-amplitude electrophysiological phasic events, alternating with quieter “core periods.” High-amplitude and core state properties cannot be disentangled with PET and fMRI. Here from high temporal resolution magnetoencephalography data, regional changes in neuronal activity were extracted during core periods in different frequency bands for each sleep stage and waking. We found that gamma-band activity increases in precuneus during light sleep (stages 1/2) and in the left dorso–medial prefrontal cortex (L-DMPFC) during deep sleep (stages 3/4). The L-DMPFC activated area expands laterally during rapid eye movement (REM) sleep, into a volume of about 5 cm 3 bounded by regions attributed to Theory of Mind (ToM) and default systems, both involved in introspection. Gamma band activity in this area was higher during REM sleep than other sleep stages and active wakefulness. There is a tantalizing correspondence between increased wide-band activity (dominated by low frequencies) in early non-REM (NREM) sleep stages and increases in gamma-band activity in late NREM and REM periods that we attribute to a lateral disinhibition mechanism. The results provide a description of regional electrophysiological changes in awake state, light and deep sleep, and REM sleep. These changes are most pronounced in the L-DMPFC and the other areas around the dorsal midline that are close to, but do not overlap with areas of the default and ToM systems, suggesting that the DMPFC, particularly in the left hemisphere, plays an important role in late NREM stages, in REM and possibly in dreaming.

Sex and Age Differences in Sleep Macroarchitecture in Childhood and Adolescent Depression

To evaluate age and sex differences in sleep macroarchitecture in children and adolescents with major depressive disorder. Ninety-seven (50 F, 47 M) symptomatic unmedicated depressed outpatients were compared with 76 healthy controls (42 F, 34 M) matched for age and sex. Participants spent 2 consecutive nights in the sleep laboratory. One hundred seventy-three children and adolescents, aged 8 to 18 years. Significant group-by-age-by-sex interactions were evident for total sleep period, percentage of Stage 1 sleep, percentage of Stage 2, percentage of slow-wave sleep, and rapid eye movement (REM) sleep latency. The depressed adolescent boys had the greatest sleep disturbance with the highest amount of percentage of Stage 1 sleep, the shortest REM latency, and the least percentage of slow-wave sleep and number of minutes of slow-wave sleep in the first non-REM period. There were minimal age differences in sleep parameters between depressed children and adolescent girls. Within age groups, the sex differences were minimal in the healthy controls. The sex differences within the depressed group were substantially larger than controls. These findings suggest a differential developmental influence on sleep in early-onset depression that is heavily dependent on sex. Sex differences are substantially smaller in healthy individuals compared with those with depression, in agreement with previous studies in depressed adults.

Sleep Laboratory Study on Single and Repeated Dose Effects of Paroxetine, Alprazolam and Their Combination in Healthy Young Volunteers

Aims: To evaluate the potential interaction of 20 mg paroxetine and 1 mg alprazolam (early morning once-daily administration) on polysomnographic (PSG) sleep and subjective sleep and awakening quality, both after a single intake and after reaching a steady-state concentration. Methods: Twenty-two (11 for the PSG) healthy young volunteers of both sexes with no history of sleep disturbances (Pittsburgh Sleep Quality Index <5) participated in a double-blind, double-dummy, placebo-controlled, repeated-dose, 4-period, cross-over study. All volunteers received all 4 treatment sequences: paroxetine–alprazolam placebo (PAP); paroxetine placebo–alprazolam (PPA); paroxetine–alprazolam (PA), and paroxetine placebo–alprazolam placebo (PLA), in a randomized order. Each treatment was administered over 15 consecutive days, with a treatment-free interval of 7 days prior to the subsequent study period. In each experimental period, one PSG sleep study was performed on the 1st night (single-dose effects) and another study was performed on the 15th night (repeated-dose effects). Additionally, two other PSG studies were assessed: an adaptation recording, and a control night recording. All-night PSG recordings were obtained following standard procedures. Each 30-second period was scored according to the criteria of Rechtschaffen and Kales by means of an automatic sleep analysis system: Somnolyzer 24x7^TM. A self-rating scale for sleep and awakening quality and early morning behavior was completed no later than 15 min after awakening over the 15 days of each experimental intervention. General lineal models (treatment/time) were applied separately to each variable. Results: (1) No significant effects were observed in any sleep variables when control nights were compared with the 1st night with PLA. (2) Sleep continuity: After PAP a clear awakening effect was seen both in the first and second evaluations, mainly in wake time, movement time, number of awakenings and stage-1 duration. After PPA an evident hypnotic effect was observed on night 1. This effect was mainly observed in maintenance variables and slightly in sleep initiation variables; it had decreased by night 15. After PA an intermediate behavior in the variables related to sleep continuity was seen, highlighting the absence of the tolerance phenomenon observed when PPA was administered alone. (3) Sleep architecture: The most important effects in REM sleep were observed after PAP; an increase in REM latency and decreases in REM sleep. PAP also induced decreases in the number of non-REM and REM periods and increases in the average duration of non-REM periods and sleep cycles. PA presented a similar pattern to PAP, and PPA similar to PLA. In relation to non-REM sleep, PA showed more stage-2 and less slow-wave sleep (SWS). (4) Subjective perception: No significant differences were observed between treatments while they were being taken, but impairments in subjective sleep quality, awaking quality, latency and efficiency were seen, mainly after PA but also after PPA discontinuations. Conclusion: The combination of PAP and PPA presented an intermediate pattern in relation to sleep continuity, with less awaking effect than PAP alone and less hypnotic effect than PPA alone, and without developing tolerance. The PAP and PPA combination also showed a similar effect to PAP on REM sleep and was the treatment with the longest stage 2 and shortest SWS. No subjective sleep and awakening effects were seen during drug intake but subjective withdrawal reports were seen after abrupt interruption. The high agreement rate for the epoch-by-epoch comparison between automatic and human scoring confirms the validity of the Somnolyzer 24x7 and thus facilitates sleep studies in neuropsychopharmacological research.

Sleep microstructure around sleep onset differentiates major depressive insomnia from primary insomnia.

In the present study we investigate whether alterations of sleep propensity or of wake propensity are implicated in sleep initiation disturbances encountered in major depressive insomnia and in primary insomnia. For this purpose, the time course of electroencephalogram (EEG) power density during the period preceding sleep onset and during the first non-rapid eye movement (REM) period was examined in three age and gender matched groups of 10 women and 11 men (healthy controls, primary insomniacs and depressive insomniacs). In contrast to healthy controls and depressive insomniacs, patients with primary insomnia did not experience a gradual decrease of their alpha and beta1 power during the sleep onset period and had a lower delta activity in the 5 min preceding sleep onset. Compared with the two other groups, depressive patients exhibit less dynamic changes in slow wave activity during the first non-REM period. The present results suggest that hyperarousal (high 'Process W') may mainly be implicated in the sleep initiation difficulties of primary insomniacs whereas the homeostatic sleep regulation process seems to be partially maintained. In our major depressed patients, the sleep initiation disturbances appeared to relate to a lower sleep pressure (low 'Process S') rather than to hyperarousal. This study supports the idea that different mechanisms are implicated in sleep disturbances experienced by primary insomniacs and major depressive insomniacs.

On the role of menopause for sleep-endocrine alterations associated with major depression

Aging and menopause are associated with alterations of the sleep EEG, while age-related changes of the hypothalamo-pituitary-adrenal (HPA) axis remain controversial. Major depression is also associated with typical sleep-endocrine changes, including enhanced activity of the HPA axis, while an influence of age and gender on these alterations is less clear. To test the hypothesis that after menopause sleep-endocrine alterations associated with major depression are accentuated, we examined the sleep EEG and nocturnal hormone secretion (ACTH, cortisol, GH, estradiol, LH, FSH, and leptin) in 16 drug-free female patients, mostly with the first episode of a major depressive disorder (seven pre- and nine postmenopausal subjects) and 19 female controls (10 subjects in the early follicular phase and nine postmenopausal subjects). Nocturnal cortisol secretion was increased in postmenopausal patients with depression, while a decrease was noted in postmenopausal controls. Sleep alterations typically associated with depression, namely a reduction in sleep continuity and slow wave sleep (SWS) and an increase in REM density, were prominent in post- but not in premenopausal patients. An inverse correlation was noted between the decline in SWS and sleep continuity and FSH secretion in patients with depression, suggesting a role of menopause for these sleep-endocrine alterations typically associated with major depression. In contrast, in premenopausal patients we noted primarily a shift in SWS and delta-EEG activity from the first to the second non-REM period, which was not related to age or hormone secretion. Though the relatively small number of subjects per group precludes a definitive conclusion, our data open up the possibility that the sleep-endocrine changes typically associated with major depression are most prominent in postmenopausal patients. Whether the predominant alteration of the distribution of SWS and delta EEG activity in younger patients with a first episode of major depression has a predictive value for the future course of the disease remains to be investigated.

Selected Contribution: Regulation of sleep-wake states in response to intermittent hypoxic stimuli applied only in sleep.

Recurrent sleep-related hypoxia occurs in common disorders such as obstructive sleep apnea (OSA). The marked changes in sleep after treatment suggest that stimuli associated with OSA (e.g., intermittent hypoxia) may significantly modulate sleep regulation. However, no studies have investigated the independent effects of intermittent sleep-related hypoxia on sleep regulation and recovery sleep after removal of intermittent hypoxia. Ten rats were implanted with telemetry units to record the electroencephalogram (EEG), neck electromyogram, and body temperature. After >7 days recovery, a computer algorithm detected sleep-wake states and triggered hypoxic stimuli (10% O2) or room air stimuli only during sleep for a 3-h period. Sleep-wake states were also recorded for a 3-h recovery period after the stimuli. Each rat received an average of 69.0 +/- 6.9 hypoxic stimuli during sleep. The non-rapid eye movement (non-REM) and rapid-eye-movement (REM) sleep episodes averaged 50.1 +/- 3.2 and 58.9 +/- 6.6 s, respectively, with the hypoxic stimuli, with 32.3 +/- 3.2 and 58.6 +/- 4.8 s of these periods being spent in hypoxia. Compared with results for room air controls, hypoxic stimuli led to increased wakefulness (P < 0.005), nonsignificant changes in non-REM sleep, and reduced REM sleep (P < 0.001). With hypoxic stimuli, wakefulness episodes were longer and more frequent, non-REM periods were shorter and more frequent, and REM episodes were shorter and less frequent (P < 0.015). Hypoxic stimuli also increased faster frequencies in the EEG (P < 0.005). These effects of hypoxic stimuli were reversed on return to room air. There was a rebound increase in REM sleep, increased slower non-REM EEG frequencies, and decreased wakefulness (P < 0.001). The results show that sleep-specific hypoxia leads to significant modulation of sleep-wake regulation both during and after application of the intermittent hypoxic stimuli. This study is the first to determine the independent effects of sleep-related hypoxia on sleep regulation that approximates OSA before and after treatment.

Slow-wave activity during non-REM sleep in men with schizophrenia and major depressive disorders

Both major depressive disorders (MDD) and schizophrenia (SZ) have been associated with reductions in slow-wave (Stages 3 and 4) sleep, although these findings are controversial. The present study compared quantitative EEG measures of slow-wave activity (0.5–4 Hz) during non-REM (NREM) sleep among age-matched, symptomatic but unmedicated, depressed, schizophrenic and healthy control men ( n=13/group). The amplitude of slow-wave activity (SWA) in the first NREM sleep period was significantly lower in both the MDD and SZ groups compared with controls. However, the time course of SWA, its accumulation and dissipation over all NREM sleep time, was abnormal in the MDD group but not in those with SZ. These findings suggest that the regulation of SWA is impaired in men with MDD but not in SZ. Thus, although those with SZ show reduced amplitude SWA in the first NREM period, there is no evidence that homeostatic regulation of SWA is impaired in this psychiatric group.

Maintenance nortriptyline effects on electroencephalographic sleep in elderly patients with recurrent major depression: Double-blind, placebo- and plasma-level-controlled evaluation

Our aim was to contrast the effects of maintenance nortriptyline and placebo on electroencephalographic sleep measures in elderly recurrent depressives who survived 1-year without recurrence of depression. Patients on nortriptyline took longer to fall asleep and did not maintain sleep better than patients on placebo; however, maintenance nortriptyline was associated with more delta-wave production and higher delta-wave density in the first non-REM (NREM) period relative to the second. Nortriptyline levels were positively but weakly related to all-night delta-wave production during maintenance (accounting for 6.6% of the variance in delta-wave counts). Total phasic REM activity increased 100% under chronic nortriptyline relative to placebo, with a robust increase in the rate of REM activity generation across the night. Effective long-term pharmacotherapy of recurrent major depression is associated with enhancement in the rate of delta-wave production in the first NREM period (i.e., delta sleep ratio) and of REM activity throughout the night.

Online detection of rem sleep based on the comprehensive evaluation of short adjacent eeg segments by artificial neural networks

1. 1. For scientific and clinical requirements the present objective is a robust automatic online algorithm to detect rapid eye movement (REM) steep from single channel sleep EEG data without using EMG or EOG information. 2. 2. For data preprocessing 20 seconds time periods of the continuous EEG activity are digitally filtered in 7 frequency bands. Then the RMS values of these filtered signals are calculated along segments of 2.5 seconds. The resulting matrix of RMS values is representing information on the power of the signal localized in time and frequency and serves as input to an artificial neural network. A pooled set of EEG data together with the corresponding manual evaluation of the recordings was used in the training process. 3. 3. Afterwards more than 90 % of the time periods not belonging to the training set could be correctly labeled Into REM and nonREM periods. In comparison to an older algorithm based on RMS values calculated along segments of 20 seconds, the error rate could be reduced by 20 %.