Showing papers on "Non-rapid eye movement sleep published in 1994"

Dependence on REM sleep of overnight improvement of a perceptual skill

Abstract: Several paradigms of perceptual learning suggest that practice can trigger long-term, experience-dependent changes in the adult visual system of humans. As shown here, performance of a basic visual discrimination task improved after a normal night's sleep. Selective disruption of rapid eye movement (REM) sleep resulted in no performance gain during a comparable sleep interval, although non-REM slow-wave sleep disruption did not affect improvement. On the other hand, deprivation of REM sleep had no detrimental effects on the performance of a similar, but previously learned, task. These results indicate that a process of human memory consolidation, active during sleep, is strongly dependent on REM sleep.

Effect of unilateral somatosensory stimulation prior to sleep on the sleep EEG in humans.

Abstract: SUMMARY The hypothesis that local activation of brain regions during wakefulness affects the EEG recorded from these regions during sleep was tested by applying vibratory stimuli to one hand prior to sleep. Eight subjects slept in the laboratory for five consecutive nights. During a 6-h period prior to night 3, either the left or the right hand was vibrated intermittently (20 min on-8 min off), while prior to night 5 the same treatment was applied to the contralateral hand. The sleep EEG was recorded from frontal, central, parietal and occipital derivations and subjected to spectral analysis. The interhemispheric asymmetry index (IAI) was calculated for spectral power in nonREM sleep in the frequency range 0.25-25.0 Hz for 0.5-Hz or 1-Hz bins. In the first hour of sleep following right-hand stimulation, the IAI of the central derivation was increased relative to baseline, which corresponds to a shift of power towards the left hemisphere. This effect was most prominent in the delta range, was limited to the first hour of sleep and was restricted to the central derivation situated over the somatosensory cortex. No significant changes were observed following left-hand stimulation. Although the effect was small, it is consistent with the hypothesis that the activation of specific neuronal populations during wakefulness may have repercussions on their electrical activity pattern during subsequent sleep.

Sleep cycles and alpha-delta sleep in fibromyalgia syndrome.

Abstract: Objective Fibromyalgia syndrome (FMS) is a musculoskeletal disorder characterized by generalized pain, localized tender points, chronic fatigue and nonrestorative sleep. Since sleep disturbances frequently occur in FMS and alpha intrusion in nonrapid eye movement (NREM) sleep probably associates with the nonrefreshing sleep, we prospectively studied the delta and alpha activity and alpha-delta ratio across sleep cycles, performing polysomnography in 10 patients with FMS and in 14 healthy control subjects. Methods Night long polysomnography recordings were performed in all subjects. Sleep scoring was done visually according to Rechtschaffen and Kales criteria. By means of spectral analysis the conventional electroencephalogram (EEG) frequency bands were automatically computed for the all night recordings. For alpha and delta power the integrated and normalized values were calculated for each sleep cycle, the evolution of these activities across successive sleep cycles was studied. Results Alpha-delta patterns occurred in almost all the patients who had also superficial and fragmented sleep with increased awakenings and reduced REM and slow wave sleep. Delta decay across sleep cycles was different in FMS and alpha activity was greater and declined, whereas the controls were persistently low throughout their sleep. Alpha-delta ratio increased progressively in successive sleep cycles; this was again different from controls. Conclusion Patients with FMS presented a high frequency of subjective sleep disturbances, an increased incidence of alpha EEG NREM sleep and clear abnormalities in sleep cycle organization.

Associations of sleep with everyday mood, minor symptoms and social interaction experience

Abstract: Although there are strong popular beliefs about the value of a good night's sleep, there is very little documented evidence of day-to-day relations between sleep and well-being In this study, covariations between sleep and both prior and subsequent daily states of well-being were studied in a healthy, employed sample Thirty volunteers used pocket computers to complete a daily sleep diary and self-rating scales of mood, minor symptoms and social interaction experience These were recorded every 2 hours for 14 days except during sleep periods A pooled regression analysis showed small but significant relationships between many of the sleep and well-being measures Sleep appeared to be more strongly related to subsequent well-being than prior well-being An earlier onset of sleep was associated with better mood and social interaction experience the following day and was a better predictor than sleep duration This result was interpreted to be consistent with the phase angle model of chronobiologic mood disorders In general, the results suggest that the sleep disturbances found in affective disorders may not be pathological but instead represent the extremes of normal relationships between sleep and well-being

Changes in Sleep and Sleep Electroencephalogram During Pregnancy

Abstract: The impairment of sleep quality is a common complaint during pregnancy. To investigate the changes in sleep in the course of pregnancy, the sleep electroencephalogram (EEG) was recorded and analyzed in nine healthy women on 2 consecutive nights during each trimester of pregnancy. Waking after sleep onset increased from the second (TR2) to the third (TR3) trimester, whereas rapid eye movement (REM) sleep decreased from the first trimester (TR1) to TR2. Spectral analysis of the EEG in nonrapid eye movement (NREM) sleep revealed a progressive reduction of power density in the course of pregnancy. In comparison to TR1, the values in TR2 were significantly lower in the 10.25-11.0-Hz and 14.25-17.0-Hz bands. In TR3, the significant reduction extended over the ranges of 1.25-12.0 Hz and 13.25-16.0 Hz. The largest decrease (30%) occurred in the 14.25-15.0-Hz band. In REM sleep, the spindle frequency range was not affected, and a minor reduction of power density in some frequency bins below 12 Hz was present only in TR3. The study documents major alterations of the sleep EEG that are not evident from the sleep scores and that may be associated with the characteristic hormonal changes occurring during pregnancy.

Scoring transitions to REM sleep in rats based on the EEG phenomena of pre-REM sleep: an improved analysis of sleep structure.

Abstract: Algorithms for scoring sleep/waking states and transitions to REM sleep (NRTs) in rats are presented and validated. Both algorithms are based on electroencephalographic (EEG) power in delta (0.5-4.0 Hz), theta (6-9 Hz) and sigma (10-14 Hz) frequency bands, and electromyogram (EMG) intensity. Waking is scored when EMG intensity is high or (sigma power).(theta power) is low. Nonrapid eye movement (NREM) sleep is scored in nonwaking epochs having high (delta power)/(theta power). Rapid eye movement (REM) sleep is scored in nonwaking epochs having low (delta power)/(theta power). NRTs are identified by the EEG phenomena of the pre-REM sleep phase of NREM sleep. Algorithms are validated by comparison with records scored independently by two investigators based on visual examination of EEGs and EMGs. The sleep/waking-state scoring algorithm produces greater than 90% agreement with visual scoring. The NRT-scoring algorithm produces 88-92% agreement with visual scoring. Scoring NRTs based on the phenomena of the pre-REM sleep phase of NREM sleep, instead of relying solely on REM sleep expression for identification of REM sleep onset, reveals a significant population of brief REM sleep episodes that are ignored by most sleep cycle analyses and allows independent quantification of REM sleep timing and maintenance.

Motor dysfunction during sleep in posttraumatic stress disorder.

Abstract: A subjective disturbance of sleep, including the occurrence of repetitive, stereotypical anxiety dreams, is characteristic of posttraumatic stress disorder (PTSD). The phenomenology of the PTSD anxiety dream has seemed most consistent with an underlying rapid eye movement (REM) sleep dysfunction. However, motor behavior reportedly can accompany PTSD dreams, and normal REM sleep typically involves a nearly total paralysis of the body musculature. As a means of understanding this discrepancy, anterior tibialis muscle activity during sleep was studied in a group of Vietnam combat veterans with current PTSD and in an age-matched normal control group. The PTSD subjects had a higher percentage of REM sleep epochs with at least one prolonged twitch burst; they also were more likely to have periodic limb movements in sleep, during nonrapid eye movement sleep. Both these forms of muscle activation also have been observed in REM behavior disorder (RBD), a parasomnia characterized by the actual enactment of dream sequences during REM sleep. The identification of RBD-like signs in PTSD adds to the evidence for a fundamental disturbance of REM sleep phasic mechanisms in PTSD.

Acute effects of transdermal nicotine on sleep architecture, snoring, and sleep-disordered breathing in nonsmokers.

Abstract: Previous research has suggested that nicotine may be therapeutically useful in the treatment of sleep­ disordered breathing. The development of transdermal nicotine delivery systems has allowed us to test the overnight effectiveness of nicotine. Twenty nonsmoking subjects (10 men, 10 women) were recruited on the basis of a history of habitual snoring that was confirmed by overnight laboratory monitoring. Sub­ jects were then randomized (double-blind crossover design) to receive either placebo or an active patch that delivers 11 mg of nicotine over a 24-h period. Patches were applied at 6 P.M. and removed at 6 A.M. the following morning, at which time venous blood was obtained for determination of serum nicotine con­ centrations. Polysomnography was performed using standard techniques to assess sleep architecture and sleep-disordered breathing. Snoring was monitored with a sound-level meter and quantitatively analyzed. to determine the snoring index (SI) (number of snores per hour of sleep) and mean and maximum snoring I intensities. The age of the subjects was 46.9 ± 11.4 yr (mean ± SO) and their mean body mass index (BMI) 33.3 ± 4.6 kg/m 2. A mean nicotine level was nondetectable with placebo and 7.8 ± 2.3 ng/ml with wearing of an active patch. Nicotine decreased total sleep time (TST) by 33 min (p~ 0.01), sleep efficiency from 89.7 to 83.50/0 (p~ 0.01), and percent rapid eye movement (REM) sleep from 18.8to 15.10/0 (p ~ 0.01), and prolonged initial sleep latency (ISL) from 6.7 to 18.2min (p~ 0.01). No significant changes in non-rapid eye movement (NREM) sleep stages 1, 2, 3-4, or arousal index were detected. Although the SI was un­ changed (602 ± 177 versus 607 ± 205/h), mean snoring intensity decreased by 1.1 dB, P~ 0.01, with nicotine. A 1.4-dB reduction in maximum snoring intensity with nicotine was not significant. Although the decrease in disordered-breathing-event (DBE) frequency from 13.6 ± 15.4 to 11.4 ± 12.5/h with nicotine was not significant, a highly significant negative correlation (r = -0.71, P~ 0.001) was detected between nicotine level and DBE duration during the active-patch night. In addition, lowest Sp02 was positively cor­ related (r = 0.52, P~ 0.05)with serum nicotine level. Nausea and emesis were the predominant side effects and were experienced by 50 and 200/0 of the subjects, respectively. In conclusion, transdermal nicotine significantly disrupted sleep architecture and produced no clinically significant improvements in either snoring or sleep-disordered breathing in this group of 20 nonsmoking snorers with mild sleep-disordered breath­ ing. Increasing levels of nicotine were associated with a shorter DBE duration and less severe reductions in lowest SP02.Davila DG, Hurt RD, Offord KP, Harris CD, Shepard JW Jr. Acute effects of transdermal nicotine on sleep architecture, snoring, and sleep-disordered breathing in nonsmokers. Am J Respir

Experimental sleep fragmentation

Abstract: Thirty-six healthy young men and women (age range 21-35 years) were studied in an experimental model of sleep fragmentation. On 2 nights sleep was disrupted by presenting tones to produce brief electroencephalogram (EEG) arousals (without shortening sleep time) and daytime function was assessed the following day with the Multiple Sleep Latency Test and a divided attention performance test. The fragmentation of sleep produced significant disruption of nocturnal sleep and reduced daytime alertness. Adaptation in EEG-defined arousals occurred from the 1st to the 2nd night of fragmentation. Threshold (measured indirectly) characteristics of EEG-defined arousals were somewhat different than those of previous studies requiring behavioral awakening. The percent of tone series producing arousal, number of tones necessary for arousal and duration of the arousal all reflected heightened thresholds in stage 3/4 and rapid eye movement (REM) sleep compared to stage 1 and stage 2 sleep. In the last 3 hours of sleep versus the first 3 hours, arousals occurred less frequently, required more tones to produce, resulted in shorter durations and in fewer sleep stage changes, except for REM sleep where the converse was the case.

Sleep onset: Normal and abnormal processes.

Abstract: This text illuminates the concept that sleep onset is an active, multidimensional process rather than a mere point on the arousal continuum. It argues that mood disturbances, behavioural dysfunction and daytime functioning are closely linked to sleep disorders.

REM-sleep timing is controlled homeostatically by accumulation of REM-sleep propensity in non-REM sleep

Abstract: Sleep structure in the rat was characterized during uninterrupted full-day recordings using an analytic procedure that identifies rapid eye movement (REM) sleep episodes based on REM-sleep-onset electroencephalograph phenomena, hence independently of REM-sleep duration. The data were used to determine whether REM-sleep timing is controlled homeostatically or by an oscillatory mechanism. The findings and conclusions are that 1) non-REM (NREM) sleep episode duration is positively correlated with prior REM-sleep episode duration, suggesting that REM-sleep expression is permissive of NREM sleep; 2) mean NREM-sleep episode duration decreases after repeated brief REM-sleep episodes ( 30 s), suggesting that REM-sleep propensity increases progressively within episodes of NREM sleep; and 5) the diurnal cycle of REM-sleep expression primarily reflects modulation in the efficiency of REM-sleep maintenance. These findings support the hypothesis that REM-sleep timing is controlled by accumulation of REM-sleep propensity during NREM sleep.

Effect of Inhaled 3% CO2 on Cheyne-Stokes Respiration in Congestive Heart Failure

Abstract: Cheyne-Stokes respiration (CSR) in severe stable congestive heart failure (CHF) may be associated with significant nocturnal arterial oxygen desaturation and sleep disruption. Previous investigations of inhaled CO2 in CSR have been uncontrolled and of short duration, sleep has not been monitored electroencephalographically, and most patients studied have had neurological disease with or without cardiac disease. The purpose of our study was to document the effects of inhaled CO2 on CSR in patients with severe stable CHF (left ventricular ejection fraction < 35% and NYHA class 3 or 4 dyspnea) in controlled all-night polysomnographic studies. Six patients were studied for 3 nights and days: adaptation, control and inhalation of CO2. These patients received a constant F1CO2 = 0.03 in air (with a 4-5 mm Hg increase in PaCO2) on night 3. This caused virtual abolition of CSR as reflected by CSR duration/total sleep time (62-2.2%; p = 0.0012) and CSR duration/nonrapid eye movement (NREM) sleep time (73-2.4%; p = 0.00064), and NREM apnea index was reduced from 33.5 to zero (p = 0.026). The apparatus used to accurately control F1CO2, however, was intrusive and some features of sleep structure such as sleep latency were adversely affected. We conclude that inhalation of CO2 with a constant F1CO2 = 0.03 virtually eradicates CSR in all-night polysomnographically monitored studies in patients with severe stable CHF. The clinical significance of these findings remains to be determined.

Anti-interleukin-1 beta reduces sleep and sleep rebound after sleep deprivation in rats

Abstract: Interleukin-1 (IL-1) is somnogenic and is hypothesized to be involved in physiological sleep regulation. Antibodies directed against rat IL-1 beta were used to further elucidate possible contributions of IL-1 to sleep regulation. Rabbit anti-rat IL-1 beta (anti-IL-1 beta) was injected intracerebroventricularly into normal rats 15 min before light onset. A 20-microgram dose of anti-IL-1 beta reduced non-rapid-eye-movement (NREM) sleep by 60 min during the subsequent 12-h slight period. There was no effect on rapid eye movement sleep after this dose of anti-IL-1 beta. The effects of anti-IL-1 beta on the enhancement of sleep after periods of sleep deprivation were also determined. When rats were deprived of sleep for 3-h beginning at light onset, the amount of time spent in NREM sleep increased for the remaining 9 h of the light period, regardless of whether control intracerebroventricular injections of pyrogen-free saline or rabbit immunoglobulin G were given during the deprivation period. However, when 20 micrograms anti-IL-1 beta were injected intracerebroventricularly during the sleep deprivation period, the expected NREM sleep rebound was completely blocked. Collectively, these data provide additional support for the hypothesis that IL-1 is involved in regulation of physiological sleep-wake activity.

Sleep fragmentation in normals: a model for sleepiness associated with upper airway resistance syndrome.

Abstract: Summary: Eight young adults underwent I night of auditory sleep fragmentation followed by four naps of the multiple sleep latency test and performance testing the next day. A latin-square design was used to compare results with baseline. Efforts were made to eliminate effects of learning on repeated performance tests. A mean of 303 arousals, lasting a mean of II seconds, disrupted nocturnal sleep. This sleep fragmentation was induced to mimic as closely as possible the nocturnal sleep disruption seen in subjects with upper airway resistance syndrome. There was a significant disruption of nocturnal sleep architecture with a significant overall decrease in slow-wave sleep (SWS) and a significant but more moderate decrease in rapid eye movement (REM) sleep during the fragmented night. The most interesting finding related to analysis by thirds of the night, which indicated an important increase over time in arousal threshold during SWS followed by REM sleep. This threshold increase was associated with a parallel increase in dB(A) levels needed to induce an arousal. Stages I and 2 nonrapid eye movement (NREM) sleep were less affected by the stimulation, but the amount of stage I NREM sleep decreased from the beginning to the end of the night, again indicating an increase in pressure to sleep. Following I night of sleep fragmentation, subjects had significantly shorter sleep latencies on the multiple sleep latency test for naps 2, 3 and 4. There was a significant relationship between percent nocturnal SWS and mean sleep latencies. The selected performance tests were not affected by I night of sleep fragmentation, despite the obvious sleepiness. Key Words: Sleep fragmentation­ Upper airway resistance syndrome-Sleepiness-Performance testing.

Ontogenetic variations in auditory arousal threshold during sleep

Abstract: Developmental variations in auditory arousal thresholds during sleep were investigated in four groups of normal male subjects--children, preadolescents, adolescents, and young adults. Arousal thresholds were determined during NREM and REM sleep for tones presented via earphone insert on a single night following two adaptation nights of undisturbed sleep. Age-related relationships were observed for both awakening frequency and stimulus intensity required to effect awakening, with awakenings occurring more frequently in response to lower stimulus intensities with increasing age. Although stimulus intensities required for awakening were high and statistically equivalent across sleep stages in nonadults, higher intensity stimuli were required in Stage 4 relative to Stage 2 and REM sleep in adults. These results confirm previous observations of marked resistance to awakening during sleep in preadolescent children and suggest that processes underlying awakening from sleep undergo systematic modification during ontogenetic development.

Nocturnal Eating Syndrome in Adults

Abstract: Ten adult subjects were referred to our sleep disorders center complaining of difficulty in maintaining sleep due to frequent and recurrent awakenings to eat or drink. All patients manifested more than one episode per night, characterized by compulsive food seeking and a return to sleep only after adequate food intake. Food-seeking drive was described as an urgent abnormal need to swallow food and was associated with an absence of real hunger. Six subjects showed an elective nighttime intake of carbohydrates, and in all cases only edible substances were injected. The patients were always fully awake during the episodes and could clearly recall them in the morning. Polysomnographic investigation showed low levels of sleep efficiency, a high number of awakenings and a strict relation between nocturnal eating episodes and nonrapid eye movement (NREM) sleep. The average length of each episode was 3.5 minutes. The "eating latency", that is the interval between awakening and chewing start, was shorter than 30 seconds in 50% of the episodes. No medical, hormonal or neurological disorders were found during clinical and laboratory investigations. Body mass index was abnormally high in six patients. Anorexia nervosa and bulimia were carefully excluded. Various psychiatric disturbances were found in nine subjects, who were nevertheless well-functioning adults. Concurrent dyssomniac disorders, such as narcolepsy or periodic leg movements occasionally associated with restless legs syndrome, were diagnosed in five patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of respiration and heart rate during wakefulness and sleep in elephant seal pups.

Abstract: Although breath holding during diving has been studied extensively in seals, the recent observation that these mammals also exhibit long-duration apnea while apparently sleeping has not been systematically examined. This project examined sleep apnea in northern elephant seal pups (Mirounga angustirostris). The animals exhibited a sequential sleep pattern of wakefulness-slow-wave sleep (SWS)-rapid eye movement (REM) sleep that resembled the normal pattern of mammalian sleep. The typical respiratory pattern during sleep in 4-mo-old pups consisted of short periods of continuous breathing separated by periods of apnea of up to 12 min. Several cycles of apnea and eupnea could occur during a single sleep episode. Breathing during a sleep cycle occurred only in SWS, never during REM sleep. The eupneic heart rate was characterized by significant sinus arrhythmia, and the apneic heart rate was similar to the minimum value during normal sinus arrhythmia. Patterns of change in breathing and heart rate associated with wakefulness and sleep were similar in seals sleeping underwater and on land. When sleeping underwater, the seals raised their heads to the surface to breathe without awakening. The changes in heart rate associated with normal sinus arrhythmia, sleep apnea, and diving apnea appear to be similar, suggesting regulation by a common homeostatic control mechanism.

The prevalence of self-reported sleep disturbances in young adults

Abstract: The prevalence of seven common patterns of sleep disturbance (delayed sleep onset, frequent wakenings, early wakening, waking tired, disrupted sleep, day napping and nightmares) was assessed in 2,782 young adults (age 17 to 30 years). Only 36% of the sample reported that they were completely free of any sleep disturbance. The data suggest that the various sleep complaints are relatively independent, with low intercorrelations. There were significant sex differences for some problems. Women were more likely to have nightmares, delayed sleep onset and frequent night wakenings, while males were more likely to engage in day napping. These data provide a measure of the prevalence of common sleep disorders and are presented in a format which should facilitate their use for comparative or normative purposes.

Relationship between cerebral blood flow velocities and cerebral electrical activity in sleep.

Abstract: The dynamics of cerebral blood flow velocity during sleep were measured in the right and left middle cerebral artery of 12 and 10 healthy male volunteers, respectively. A computer-assisted pulsed (2-MHz) Doppler ultrasonography system was modified for continuous long-term and on-line recording of cerebral hemodynamics in combination with polysomnography. Mean flow velocity (MFV) decreased steadily during deepening nonrapid eye movement (NREM) sleep and increased suddenly during rapid eye movement sleep, corresponding to changes in brain function. However, spontaneous or provoked changes in sleep stage patterns as well as awakenings from NREM sleep were not regularly accompanied by corresponding changes in MFV. Differing values for MFV in subsequent sleep cycles could be shown for several sleep stages. Furthermore, MFV values in sleep stage II at the end of an NREM-sleep period were lower than in preceding slow-wave sleep. After application of short acoustic signals the electroencephalogram frequency rose, indicating an arousal, whereas MFV rapidly decreased for several seconds and then gradually returned to the prior level. These results imply an uncoupling between cerebral electrical activity and cerebral perfusion during sleep and support a dissociation in the activity of central regulatory mechanisms. In light of the proposal that cortical energy consumption can be accounted for by cerebral electrical activity, the concept that cerebral perfusion during sleep is regulated solely by the metabolic rate must be reconsidered.

Sleep in depression: the influence of age, gender and diagnostic subtype on baseline sleep and the cholinergic REM induction test with RS 86

Abstract: One hundred and eight healthy controls and 178 patients with a major depressive disorder according to DSM-III were investigated in the sleep laboratory after a 7-day drug wash-out period. Subsamples of 36 healthy controls and 56 patients additionally took part in the cholinergic rapid eye movement (REM) sleep induction test with RS 86. Data analysis revealed that age exerted powerful influences on sleep in control subjects and depressed patients. Sleep efficiency and amount of slow wave sleep (SWS) decreased with age, whereas the number of awakenings, early morning awakening, and amounts of wake time and stage 1 increased with age. REM latency was negatively correlated with age only in the group of patients with a major depression. Statistical analysis revealed group differences for almost all parameters of sleep continuity with disturbed indices in the depressed group. Differences in SWS were not detected. REM latency and REM density were altered in depression compared to healthy subjects. Sex differences existed for the amounts of stage 1 and SWS. The cholinergic REM induction test resulted in a significantly more pronounced induction of REM sleep in depressed patients compared with healthy controls, provoking sleep onset REM periods as well in those depressed patients showing baseline REM latencies in the normal range. Depressed patients with or without melancholia (according to DSM-III) did not differ from each other, either concerning baseline sleep or with respect to the results of the cholinergic REM induction test. The results stress the importance of age when comparing sleep patterns of healthy controls with those of depressed patients. Furthermore they underline the usefulness of the cholinergic REM induction test for differentiating depressed patients from healthy controls and support the reciprocal interaction model of nonREM-REM regulation and the cholinergic-aminergic imbalance hypothesis of affective disorders.

Sleep EEG of patients with obsessive-compulsive disorder

Abstract: Twenty-two patients suffering from an obsessive and compulsive disorder (OCD) according to DSM-III-R were investigated by polysomnographic sleep EEG recordings under drug-free conditions and compared to age- and sex-matched healthy controls. Sleep efficiency was significantly lower and wake % SPT was significantly increased in the patient group compared to healthy subjects. Sleep architecture did not differ among the two samples. Especially REM sleep measures, in particular, REM latency did not differ among the groups. No positive correlation was found between sleep variables and rating inventories for obsession and compulsions (Y-BOCS), depression (Hamilton) and anxiety (CAS). A secondary depression did not influence sleep EEG variables. The results of this study contradict the assumption that OCD patients show REM sleep and slow wave sleep abnormalities similar to those shown by patients with primary depression.

Sleep and arousal, synchrony and independence, among mothers and infants sleeping apart and together (same bed): an experiment in evolutionary medicine

Abstract: Although solitary sleeping in infancy is a very recent custom, limited to Western industrialized societies, and most contemporary people practice parent-infant co-sleeping, virtually all laboratory research on sleep in human infants assumes that solitary infant sleep is the normal and desirable environment. We have used evolutionary and developmental data to challenge this view. We suggest that co-sleeping provides a sensory-rich environment which is the more appropriate environment in which to study infant sleep. In addition, two preliminary, in-laboratory, polygraphic investigations of mother-infant co-sleeping are reported in normal infants, within the peak age range for sudden infant death syndrome (SIDS). Five mother-infant pairs co-slept one night in the first study; in the second, three additional pairs slept separately for two nights and co-slept the third consecutive night. The results suggest that co-sleeping is associated with enhanced infant arousals and striking temporal overlap (synchronicity) in infant and maternal arousals, and that, possibly as a result, co-sleeping mothers and infants spend more time in the same sleep stage or awake condition. The implications of the hypothesis and preliminary results for research on the normal development of infant sleep and on SIDS are discussed.