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At least 523 records · Page 29Linked to original sources
PubMed2001

Relationship between Delta, Sigma, Beta, and Gamma EEG bands at REM sleep onset and REM sleep end.

OBJECTIVE: The aim of the present study was to analyze in detail the relationship of two newly introduced measures, related to the Beta and Gamma EEG bands during REM sleep, with Delta and Sigma activity at REM sleep onset and REM sleep end, in order to understand their eventual role in the sleep modulation mechanism. METHODS: For this purpose, power spectra of 1 EEG channel (C4, referred to A1) were obtained by means of the fast Fourier transform and the power of the bands ranging 0.75-4.50 Hz (Delta), 4.75-7.75 (Theta), 8.00-12.25 (Alpha), 12.50-15.00 (Sigma), 15.25-24.75 (Beta), 25.00-34.75 (Gamma 1), and 35.00-44.75 (Gamma 2) was calculated for the whole period of analysis (7 h), in 10 healthy subjects. Additionally, two other time series were calculated: the ratio between Beta and Gamma2, and between Gamma1 and Gamma2 (Beta and Gamma ratios). For each subject, we extracted 3 epochs of 30 min corresponding to the 15 min preceding and the 15 min following the onset of the first 3 REM episodes. Data were then averaged in order to obtain group mean values and standard deviation. The same process was applied to the 30-min epochs around REM sleep end. RESULTS: The course of the Delta band around REM sleep onset was found to be characterized by a first phase of slow decline lasting from the beginning of our window up to a few seconds before REM onset; this phase was followed by a sudden, short decrease centered around REM onset, lasting for approximately 1.5-2 min. At the end of this phase, the Delta band reached its lowest values and remained stable up to the end of the time window. The Sigma band showed a similar course with stable values before and after REM sleep onset. The Beta and Gamma ratios also showed a 3-phase course; the first phase, in this case, was characterized by stable low values, from the beginning of our window up to approximately 5 min before REM onset. The following second phase was characterized by an increase which reached its maximum shortly after REM sleep onset (approximately 1 min). In the last phase, both Beta and Gamma ratios showed stable high values, up to the end of our time window. At REM sleep end, the Delta band only showed a very small gradual increase, the Sigma band presented a more evident gradual increase; on the contrary, both Beta and Gamma ratios showed a small gradual decrease. CONCLUSIONS: The results of the present study show a different time synchronization of the changes in the Delta band and in Beta and Gamma ratios, at around REM sleep onset, and seem to suggest that the oscillations of these parameters might be modulated by mechanisms more complex than a simple reciprocity. All these considerations point to the fact that REM sleep can be considered as a complex phenomenon and the analysis of high-frequency EEG bands and of our Beta and Gamma ratios represent an additional important element to include in the study of this sleep stage.

Adult↗
PubMed2003

The Sleep Disorders Inventory: an instrument for studies of sleep disturbance in persons with Alzheimer's disease.

The Sleep Disorders Inventory (SDI) is an expanded version of one item of the Neuropsychiatric Inventory (NPI). It describes the frequency, severity, and caregiver burden of sleep-disturbed behaviors during a period prior to its administration. We carried out post hoc analyses on baseline responses to the SDI in 104 persons with Alzheimer's disease (AD) and live-in caregivers who had been recruited for a trial of melatonin in the treatment of sleep disturbance. These patient-participants averaged <7 h of sleep per night, measured by actigraph (sleep disturbance), for the 2-3-week period prior to administration of SDI. Data were from the 2 weeks prior to the baseline visit (SDI, NPI) including actigraph-derived sleep variables and 2 weeks' worth of sleep quality ratings (SQR) kept in a diary by caregivers, plus Mini-Mental State Examination and activities of daily living assessment at baseline. The prevalence of sleep disorder symptoms ranged from 34% (waking up at night thinking it is daytime) and 82% (getting up during the night). Worse SDI scores were associated with worse cognitive, functional, and behavioral status, but not with sex, age, education or duration of dementia. SDI scores were significantly worse in individuals meeting independently established criteria for a diagnosis of 'sleep disturbance' (<6 h total sleep time per night) whereas demographic variables and scores reflecting cognition and function were not significantly different across this grouping. The SDI covers a wide range of sleep behaviors and provides information independent of sleep time and SQR.

Aged↗
PubMed2001

Hormonal responses to exercise after partial sleep deprivation and after a hypnotic drug-induced sleep.

The aim of this study was to determine the hormonal responses, which are dependent on the sleep wake cycle, to strenuous physical exercise. Exercise was performed after different nocturnal regimens: (i) a baseline night preceded by a habituation night; (ii) two nights of partial sleep deprivation caused by a delayed bedtime or by an early awakening; and (iii) two nights of sleep after administration of either a hypnotic compound (10 mg zolpidem) or a placebo. Eight well-trained male endurance athletes with a maximal oxygen uptake of 63.5 +/- 3.8 ml x kg(-1) x min(-1) (mean value +/- s(x)) were selected on the basis of their sleeping habits and their physical training. Polygraphic recordings of EEG showed that both nights with partial sleep loss led to a decrease (P< 0.01) in stage 2 and rapid eye movement sleep. A delayed bedtime also led to a decrease (P < 0.05) in stage 1 sleep. Zolpidem had no effect on the different stages of sleep. During the afternoon after an experimental night, exercise was performed on a cycle ergometer. After a 10-min warm-up, the participants performed 30 min steady-state cycling at 75% VO(2-max) followed by a progressively increased workload until exhaustion. The recovery period lasted 30 min. Plasma growth hormone, prolactin, cortisol, catecholamine and lactate concentrations were measured at rest, during exercise and after recovery. The concentration of plasma growth hormone and catecholamine were not affected by partial sleep deprivation, whereas that of plasma prolactin was higher (P < 0.05) during the trial after an early awakening. Plasma cortisol was lower (P < 0.05) during recovery after both sleep deprivation conditions. Blood lactate was higher (P < 0.05) during submaximal exercise performed after both a delayed bedtime and an early awakening. Zolpidem-induced sleep did not affect the hormonal and metabolic responses to subsequent exercise. Our results demonstrate only minor alterations in the hormonal responses to exercise after partial sleep deprivation.

Adult↗
PubMed2001

Protecting sleep quality in later life: a pilot study of bed restriction and sleep hygiene.

We tested two interventions for improving sleep consolidation and depth in normal elderly participants: a modification of sleep-restriction therapy and sleep-hygiene education. Twenty-one elderly participants without sleep disorders were randomized to sleep hygiene plus bed restriction (i.e., restricting time in bed by 30 minutes nightly for one year) or to sleep hygiene alone. Participants in the bed-restriction group showed a median increase in sleep efficiency of 6.1% versus 1.8% in participants receiving sleep hygiene instruction, and an increase in allnight delta EEG power. Self-reported mood on awakening in the morning showed greater improvement over the first eight weeks in the sleep-hygiene condition. The use of sleep hygiene was associated with initial improvement in daytime well-being, whereas bed restriction led to sustained improvements in sleep continuity and sleep depth.

Aged↗
PubMed1996

A preliminary study of sleep in the ferret, Mustela putorius furo: a carnivore with an extremely high proportion of REM sleep.

Sleep and wakefulness were studied polygraphically in two adult male ferrets between the ages of 3 months and 2.5 years. Nine 24-hour recordings were obtained on different light/dark schedules, and one animal was also monitored for 3 days following administration of the serotonin synthesis inhibitor, parachlorophenylalanine. Stage scoring was accomplished utilizing criteria similar to those used in the cat. Certain modifications to the criteria were made to accommodate apparent differences in electrographic indicators of state. Mean daily percentages [+/- standard error of the mean (SEM)] for the major stages were: slow-wave sleep, 36.0 +/- 1.33; rapid eye movement (REM) sleep, 24.4 +/- 0.94; and wake, 39.4 +/- 1.17. Under laboratory conditions, ferrets spend over 60% of the time in sleep and 40.28% +/- 0.93% of total sleep time in REM sleep. The high amount of REM sleep is achieved by having a high number of REM sleep episodes rather than long REM periods. Sleep cycle length was computed in two ways: with long wake episodes removed, 16.7 +/- 0.4 minutes; and with all wake removed, 13.2 +/- 0.3 minutes. Sleep and waking indices in the ferret are compared to those in the cat and discussed with respect to predictions based on several constitutional variables. The high amount of REM sleep and the relative immaturity of the ferret at birth lends additional support for a functional role of REM sleep on ontogenetic development.

Animals↗
PubMed2005

Chronotype and sex effects on sleep architecture and quantitative sleep EEG in healthy young adults.

STUDY OBJECTIVES: To evaluate the influence of chronotype (morning types and evening types) on sleep stages and quantitative sleep electroencephalograms when constraints on the sleep schedule are minimal and when sex difference is taken into account. DESIGN: A 48-hour session in the laboratory, including 2 nights of polysomnography, preceded by 7 days of ambulatory actigraphy. SETTING: Chronobiology laboratory. PARTICIPANTS: Twenty-four healthy young subjects: 12 morning types and 12 evening types selected by questionnaire. Each group included 6 men and 6 women. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: A polysomnography night of 8 hours in duration was recorded according to preferred sleep schedule. Sleep-stage analysis revealed that morning types and evening types did not differ in sleep architecture. However, morning-type men showed a higher percentage of stage 1 sleep and lower sleep efficiency than evening-type men. Electroencephalogram spectral analysis was conducted in non-rapid eye movement sleep for 6 frequency bands. Morning types had more spectral power in low sigma (12-14 Hz) compared with evening types. The most robust difference between women and men was found in high sigma (14-16 Hz) and was not present between chronotypes. The decay rate of slow-wave activity (1-5 Hz) tended to be faster in morning types compared with evening types (P = .06). This rate was almost identical for women and men. CONCLUSIONS: These results agree with the hypothesis that homeostatic sleep regulation differs between morning types and evening types, with morning types showing indications of a higher rate of dissipation of sleep pressure during the night. Morningness-eveningness seems to affect sleep in a sex-specific manner, with men being more affected by their chronotype.

Adult↗
PubMed2004

Sleep problems in children with an intellectual disability: parental perceptions of sleep problems, and views of treatment effectiveness.

BACKGROUND: Sleep problems are common in children with an intellectual disability (ID), often lasting for many years. Many parents do not perceive their child to have a sleep problem, do not believe treatment is possible and do not seek treatment. This paper examined prevalence and duration of sleep problems in children with an ID and considered parental perceptions of sleep problems and views towards treatment. METHOD: The paper reports on two studies (n = 149 and 243 respectively) of children between 3 and 18 years, with a range of disabilities. Parents in each study completed a questionnaire about their child's sleep problems, and the type and effectiveness of any treatment used to address their child's sleep problems. RESULTS: Prevalence rates ranged between 25.5% and 36.2% for sleep problems with an average duration of between 6 and 9 years. Around half of parents had sought treatment for their child's sleep problem in Study 1, while 76% had done so in Study 2. Parental ratings regarding treatment effectiveness were higher in Study 1 than in Study 2. Contrary to expectations, behavioural treatment was not rated as significantly more effective than other treatments in either study. CONCLUSIONS: While sleep problems are common and chronic in children with an ID, parents may not recognize a sleep problem as present, often do not seek treatment for their child's sleep problems, and treatment advice and effectiveness is very variable. Thus, further research and parent and professional education regarding the identification and treatment of sleep problems in these children is required.

Adolescent↗
PubMed2003

Occurrence of periodic sleep spindles within and across non-REM sleep episodes.

Sleep spindles have been reported to occur both as single events and periodically in sequences. However, there is no systematic description about the occurrence of spindles in sequences in relation to time of night. The aim of the present study was to examine the temporal occurrence of periodic sleep spindles during the night. Sleep spindles of 19 healthy subjects were selected visually. A minimum of three consecutive spindles was required to form a spindle sequence. A 5-second upper time interval limit was applied as the longest duration between spindles belonging to a spindle sequence. The number of spindles and time occupied by spindle sequences increased from the first to the fourth non-REM (NREM) sleep episode. Within NREM sleep episodes, the number of spindles and spindle sequences dominated at the beginning. In the first two NREM sleep episodes with high slow-wave activity (SWA), there were few spindle sequences and they decreased with increasing SWA. In the third and fourth NREM sleep episode with less SWA, there were more spindle sequences and they were more evenly distributed. It is possible that in the first NREM sleep episodes, hyperpolarization of the thalamocortical cells deepens so rapidly that the NREM sleep level, where spindle sequences arise, is passed and spindle sequences are not formed. Spindle sequences could be regarded as markers of the evolution of the NREM sleep process and their lack or excess in relation to time of night and NREM sleep episode can hopefully be used to indicate changes in brain mechanisms behind NREM sleep.

Adult↗
PubMedDate not supplied

Sleep-wake cycles, social rhythms, and sleeping arrangement during Japanese childbearing family transition.

OBJECTIVE: To examine how sleep-wake cycles and social rhythms of Japanese parents are related to their sleeping arrangements before and after the birth of their first child. DESIGN: Prospective longitudinal, time-series methods. SETTING: Participants' homes in four geographical areas of Japan. PARTICIPANTS: Convenience sample of 101 Japanese first-time parent couples who completed antepartum and postpartum questionnaires. MAIN OUTCOME MEASURES: 24-hr sleep-wake rhythm from 7-day logs at 32 to 36 weeks gestation and 4 to 5 weeks postpartum and daily social rhythm from Monk's Social Rhythm Metric. RESULTS: Mothers' total sleep time and activity level decreased after birth. Social rhythms became less regular for mothers and more consistent and regular for fathers. Although sleeping arrangement had no effect on parents' daily social rhythms, it had a significant effect on the 24-hr sleep-wake rhythm. Regularity of sleep-wake rhythms was more prominent for fathers sleeping with mother and baby than for fathers sleeping alone. CONCLUSIONS: Couples having their first child face great changes in their sleep-wake cycles and social rhythms. Nurses can counsel expectant parents to think about their sleeping habits and social activities and assist them in making informed decisions about the best sleeping arrangement during transition to parenthood.

Adaptation, Psychological↗
PubMed2004

Parasomnias and sleep disordered breathing in Caucasian and Hispanic children - the Tucson children's assessment of sleep apnea study.

BACKGROUND: Recent studies in children have demonstrated that frequent occurrence of parasomnias is related to increased sleep disruption, mental disorders, physical harm, sleep disordered breathing, and parental duress. Although there have been several cross-sectional and clinical studies of parasomnias in children, there have been no large, population-based studies using full polysomnography to examine the association between parasomnias and sleep disordered breathing. The Tucson Children's Assessment of Sleep Apnea study is a community-based cohort study designed to investigate the prevalence and correlates of objectively measured sleep disordered breathing (SDB) in pre-adolescent children six to 11 years of age. This paper characterizes the relationships between parasomnias and SDB with its associated symptoms in these children. METHODS: Parents completed questionnaires pertaining to their child's sleep habits. Children had various physiological measurements completed and then were connected to the Compumedics PS-2 sleep recording system for full, unattended polysomnography in the home. A total of 480 unattended home polysomnograms were completed on a sample that was 50% female, 42.3% Hispanic, and 52.9% between the ages of six and eight years. RESULTS: Children with a Respiratory Disturbance Index of one or greater were more likely to have sleep walking (7.0% versus 2.5%, p < 0.02), sleep talking (18.3% versus 9.0%, p < 0.006), and enuresis (11.3% versus 6.3%, p < 0.08) than children with an Respiratory Disturbance Index of less than one. A higher prevalence of other sleep disturbances as well as learning problems was observed in children with parasomnia. Those with parasomnias associated with arousal were observed to have increased number of stage shifts. Small alterations in sleep architecture were found in those with enuresis. CONCLUSIONS: In this population-based cohort study, pre-adolescent school-aged children with SDB experienced more parasomnias than those without SDB. Parasomnias were associated with a higher prevalence of other sleep disturbances and learning problems. Clinical evaluation of children with parasomnias should include consideration of SDB.

Arizona↗
PubMed2003

Gender differences in symptoms related to sleep apnea in a general population and in relation to referral to sleep clinic.

STUDY OBJECTIVES: To study the prevalence, risk factors, and gender differences in symptoms related to obstructive sleep apnea. A secondary objective was to study gender differences in relation to referral to a sleep clinic for sleep investigations. DESIGN AND SETTING: A questionnaire study in a representative sample of the general population. A second cohort included patients referred for sleep apnea investigation between 1991 and 2000 in the same geographic region. PARTICIPANTS: A representative sample of 5,424 subjects aged 20 to 69 years living in northern Sweden. Responses were obtained from 4,648 subjects (85.7%). RESULTS: Of the male respondents, 17.9% stated that snoring was a problem or said that they had relatives who were concerned about witnessed sleep apnea, and of the female respondents, 7.4%. The prevalence of snoring and witnessed apneas increased with age. In men, there was a peak prevalence rate at 55 to 59 years of age, while the corresponding figure in women the peak prevalence rate was at 60 to 64 years of age. Having snoring as a problem and relatives who were concerned about witnessed sleep apnea were independently associated with male gender, age, and current smoking. Snoring as a problem also was associated with higher education. Women who snored reported significantly more daytime sleepiness than did men who snored. The estimated number of subjects aged 20 to 69 years who had snoring as a problem or had relatives who were concerned about witnessed sleep apnea in the population was 21,160. During the previous decade, 3,955 subjects had been referred to sleep laboratories, so < 20% of the estimated number of symptomatic subjects in the population had been referred during this 10-year period. The referral rate ratio for men/women after correction for population and prevalence of symptoms was 1.25:1 (p = 0.012). CONCLUSION: Experiencing snoring as a problem or having relatives who are concerned about witnessed sleep apnea are common findings in the population. However, during the last decade, only about 20% of the subjects with snoring as a problem or with relatives who are concerned about witnessed sleep apnea were referred to sleep laboratories. Women were significantly underrepresented in sleep laboratory referrals, even though women who snored experienced more subjective daytime sleepiness than men.

Adult↗
PubMed1997

Alpha sleep and information processing, perception of sleep, pain, and arousability in fibromyalgia.

This study examined the relationship between alpha sleep and information processing during sleep, perception of sleep, musculoskeletal pain, and arousability in patients with fibromyalgia. Patients (n = 20) were allowed to sleep undisturbed for the first 60 minutes of the study to assess amount of alpha sleep and were classified as high or low alpha generators based on quantitative analyses of alpha activity during this period. The groups were compared for performance on two memory tasks, perceptions of polysomnographically-defined sleep and EEG arousals in response to auditory stimuli. Correlations between symptoms of fibromyalgia and alpha activity were also examined. Alpha activity during sleep in fibromyalgic patients was associated with the perception of shallow sleep and an increased tendency to arouse in relation to auditory stimuli. Alpha activity was not associated with increased memory for auditory stimuli presented during sleep, sleep state misperception, or with myalgia symptoms. Alpha sleep appears to be, electrophysiologically, a shallow form of sleep. Our results suggest that it is perceived as such phenomenologically and that it is also associated with increased arousability.

Acoustic Stimulation↗
PubMed2004

Sleep strategies of 12-hour shift nurses with emphasis on night sleep episodes.

OBJECTIVES: Episodes of sleep during a nightshift are frequently reported in various types of jobs. This phenomenon has been seldom documented so far. This field study investigated individual differences in the sleep-wake behavior of nurses. METHODS: A group of eight nurses working in an intensive care unit on a two 12-hour shift system kept a "sleep diary" for 1 month, recording main sleep periods and naps. They subjectively assessed sleepiness, sleep quality, and the need for sleep at various times of the day and night. Continuous actimetric measurements provided an evaluation of the rest-activity patterns and of the sleep parameters. RESULTS: Half of the nurses chose to take naps in 75% of their nightshifts. No differences between the night-nappers and nonnight-nappers were found for either total sleep length or the temporal patterns of subjective sleepiness at night but, during nightwork, night-nappers needed sleep earlier than nonnight-nappers. They had long naps during a worknight and short daytime sleep, sometimes followed by a late afternoon nap. This strategy probably favored the maintenance of a diurnal orientation. Nonnight-nappers had long daytime sleep and took preventive naps to anticipate sleepiness during nightwork. However, their readjustment to diurnal life seemed more difficult than that of night-nappers. CONCLUSIONS: Nurses use different sleep-wake strategies to cope with nightwork. These different strategies may be due to circadian influence although social factors cannot be totally excluded.

France↗
PubMed1986

EEG polygraphic sleep study in divers under a 31 ATA He-O2 environment with special reference to the automated analysis of sleep stages.

This study was performed on four simulated professional divers (31 ATA, PO2 = 0.4 bar, PN2 = 0.79 bar) to investigate the function of their sleep polygraphically. All-night electrographical recording of the subjects' sleep was taken from 23:00 until 07:00 the next morning, predive, saturation, decompression, and postdive from Nov. 20 to Dec. 13, 1985. Polygraphic analysis of nocturnal sleep was done by a microcomputer technique developed by us for comparison with visual scoring. This system is a real-time processing system. Therefore, a sleep chart is completed when the experiment is finished. This system was very useful for the analysis of the tremendous volume of sleep records during a nearly one-month experiment. The following results were obtained: In the predive control, total amount of stages (3 + 4) of NREM and REM sleep decreased. In the hyperbaric environment at 31 ATA, all the divers had to interrupt their sleep once or twice for nocturnal sleep urination, and also total waking time increased during nocturnal sleep. At 31 ATA, the length and the cycle of the sleep profile vacillated. A high degree of correlation was observed between the sleep profile recorded by the polygraph and the subjective appreciation of sleep.

Atmospheric Pressure↗
PubMed1997

[Clinical aspects of sleep disorders--experiences with 817 patients of an ambulatory sleep clinic; comment].

Between 1992, the year in which the Sleep Out-Patient Clinic at the Department of Psychiatry, University of Vienna, Allgemeines Krankenhaus (General Hospital) Vienna, was established, and 1996, 817 patients (58% females, average age 52 years; 42% males, average age 48 years) were treated for sleep disorder. According to the International Statistical Classification of Diseases and Related Health Problems (ICD-10) of the World Health Organization (WHO), 70% of the patients presented with a non-organic sleep disorder and 30% with an organic sleep disorder as main diagnosis. Non-organic insomnia was by far the most frequently diagnosed sleep disorder (48%), while within the organic sleep disorders sleep apnea was dominant (12%). In regard to the additional non-organic (mental disorder) diagnoses rounding off the clinical picture, neurotic, stress related, and somatoform disorders were the most common (41%), followed by affective disorders (31%) and mental and behavioural disorders due to intake of psychoactive substances, e.g. alcohol, drugs (15%). Additional organic diagnoses related to sleep disorders involved primarily endocrine disorders such as adipositas (23%), followed by cardiovascular disorders (19%), and primary snoring (17%). The sleep out-patient clinic has at its disposal a supportive diagnostic armamentarium such as all-night sleep polysomnography, 24-hour polysomnography, the Multiple Sleep Latency Test, EEG and EEG-mapping in the affiliated sleep laboratory, the evaluation of event-related potentials (P300) and actometry in the psychophysiological laboratory, as well as psychological and psychophysiological tests in the clinical psychodiagnostic laboratory, in order to determine the right treatment or preventive measures for the individual patients.

Adult↗
PubMed1992

Good sleep, bad sleep: a meta-analysis of polysomnographic measures in insomnia, depression, and narcolepsy.

Primary insomnia, major depression, and narcolepsy are usually considered to be separate disorders, distinguished by different polysomnographic profiles. But do polysomnographic data provide adequate evidence to segregate the three disorders, or might they display fundamentally the same sleep disturbance, differing only in degree? To test the viability of these two alternate hypotheses, the authors performed a meta-analysis of controlled polysomnographic studies of these disorders. A summary measure of degree of sleep disturbance was constructed from five variables: wakefulness after sleep onset, percentage of stage 1 sleep, percentage of stage 3 + 4 sleep, rapid eye movement (REM) latency, and REM density. The results of available studies for each variable were combined using a weighted average of effect sizes. An overall "sleep disturbance index" was then calculated by combining the estimates for the five above listed variables. On both the individual measures and especially on the summary index, insomnia, depression, and narcolepsy were arrayed on a simple continuum of progressively more severe sleep disturbance--congruent with the clinical observation that these disorders display progressively more disturbed sleep. These findings suggest that sleep can be disturbed in only a limited number of ways: in evaluating sleep architecture, it may not be possible to elaborate much beyond a single axis of good-to-bad sleep. Thus, polysomnographic measures may not provide adequate evidence to classify insomnia, depression, and narcolepsy as separate entities.

Cerebral Cortex↗
PubMed1990

Sleep and EEG slow-wave activity in the domestic cat: effect of sleep deprivation.

The 24-h sleep-wake distribution, the vigilance states and the time course of EEG slow-wave activity was investigated in 8 adult domestic cats individually maintained in isolation under 14-h light (06.00-20.00 h)/10-h dim conditions. The frontal EEG and motor activity were continuously recorded for 22 h (during the daily cleaning and food-replenishing period between 07.00 and 09.00 h the cats were only observed). Sleep was prevented for 14 h (07.00-21.00 h) by playing with the animals. Recovery from sleep deprivation was recorded for the remaining 10 h of the dim period. Non-rapid eye movement (non-REM) sleep, REM sleep and waking were uniformly distributed over the light and dim period, with the exception of the 2-h feeding period where the cats were always awake. EEG power density in the delta band (0.75-4.5 Hz; slow-wave activity) was computed in non-REM sleep. The values in the light period were higher than in the dim period. In neither of the lighting periods was a trend observed. After sleep deprivation a small increase of non-REM sleep and REM sleep was present. EEG slow-wave activity was initially enhanced and then declined progressively. We conclude that despite the small circadian difference in the sleep-wake pattern observed in our cats, sleep homeostasis is similar to that observed in other mammalian species.

Animals↗
PubMed1987

Sleep and performance in young adults and older normals and insomniacs during acute sleep loss and recovery.

Many changes occur in sleep as a function of aging, but it is not known whether these changes result in sleep being less restorative. To examine the sleep restorative process, groups of 12 normal young adults and 12 normal and 12 insomniac male subjects, age 55-71, were totally sleep deprived for 64 hours and then allowed recovery sleep. Response speed, immediate recall, sleepiness, and body temperature were tested at approximately 2300, 0115, 0330, 0530 and 0800 during baseline, sleep loss, and recovery nights. Significant group (age or insomnia) by sleep loss condition interactions were found for reaction time and immediate recall performance measures. Similar significant interactions were found for oral temperature and all EEG sleep variables except total time in bed, percent stage 1, and percent REM. It was concluded that performance recovery following sleep loss was no slower in older subjects than in younger subjects despite very different recovery sleep stage parameters. This implied that aging effects on sleep are developmental rather than degenerative.

Adolescent↗