Deep Sleep State Research Articles

Evaluation of the Effect of Nest Posture on the Sleep-wake State of Premature Infants

Background: Premature birth is a major cause of infant mortality in developed countries. Newborns confined to neonatal intensive care units (NICUs) are in a rapid stage of brain development. As such, sleep plays a pivotal role in the proper brain development of newborns. However, this developmental aspect is often disregarded due to the lack of information. Aim: This study aimed to evaluate the effect of nest posture on the sleep-wake state of premature infants. Method: This cross-over clinical trial was conducted on 60 premature infants admitted in the NICU of Ghaem Hospital in Mashhad, Iran in 2015. Infants were divided into two groups of experimental and control. Data were collected using the Assessment of Premature Infants' Behavior (APIB). Neonates in the control group were placed in an incubator, and neonates in the experimental group were positioned in a nest. Between-group comparison was performed using paired-samples T-test for normal variables and Wilcoxon test for non-normal variables. Results: In this study, no statistically significant differences were observed between the two groups in terms of the scores of deep sleep state before (P=0.50) and after the intervention (P=0.59). However, during the intervention, mean score of deep sleep was higher in the experimental group (P=0.08). Moreover, mean score of slow wake state had no significant difference between the study groups before (P=0.67), after (P=0.86), and during the intervention (P=0.81). Implications for Practice: According to the results of this study, nest posture increased the deep sleep hours of premature infants as the most imperative state of brain development. Therefore, it is recommended that nest posture be used to improve the deep sleep state of premature infants.

A Multicast-Traffic-Oriented Energy-Saving Algorithm with a Hybrid Sleep Mode for EPONs

High energy consumption in Ethernet Passive Optical Networks (EPONs) has caused intense research on energy-saving methods in recent years. The most common method for EPON energy saving is to cause optical network units (ONUs) to sleep which are idle or low loaded. With the popularity of multimedia applications, the ONUs carry not only unicast traffic but also more and more multicast traffic. However, existing studies mainly focus on ONUs that support only unicast traffic. The many differences between multicast traffic and unicast traffic make it necessary to design novel energy-saving methods. This paper proposes a multicast-traffic-oriented energy-saving algorithm for EPONs, called the energy-saving algorithm for multicast traffic (ESMT). To save as much energy as possible, the proposed algorithm uses a hybrid sleep mode (composed of a deep sleep state and an independent sleep mode) in which not only can ONU enter a deep sleep state, but also the ONU transmitter and receiver can sleep independently. Simulation results show that the proposed algorithm, which is oriented to multicast traffic in EPONs, is more energy efficient than other algorithms.

Précis of Waking, Dreaming, Being: Self and Consciousness in Neuroscience, Meditation, and Philosophy

Précis of Waking, Dreaming, Being: Self and Consciousness in Neuroscience, Meditation, and Philosophy Evan Thompson (bio) The central idea of Waking, Dreaming, Being is that the self is a process, not a thing or an entity.1 The self isn’t something outside experience, hidden either in the brain or in some immaterial realm. It is an experiential process that is subject to constant change. We enact a self in the process of awareness, and this self comes and goes depending on how we are aware. When we’re awake and occupied with some manual task, we enact a bodily self geared to our immediate environment. Yet this bodily self recedes from our experience if our task becomes an absorbing mental one. If our mind wanders, the mentally imagined self of the past or future overtakes the self of the present moment. As we start to fall asleep, the sense of self slackens. Images float by, and our awareness becomes progressively absorbed in them. The impression of being a bounded individual distinct from the world dissolves. In this hypnagogic state, the borders between self and not-self seem to fall away. The feeling of being a distinct self immersed in the world comes back in the dream state. We experience the dream from the perspective of the self within it, or the dream ego. Although the entire dream world exists only as a content of our awareness, we identify our self with only a portion of it—the dream ego that centers our experience of the dream world and presents itself as the locus of our awareness. At times, however, something else happens. We realize we’re dreaming, but instead of waking up we keep right on dreaming with the knowledge that we’re dreaming. We enter what is called a lucid dream. Here we experience a different kind of awareness, one that witnesses the dream state. No matter what dream contents come and go, including the forms the dream ego takes, we can tell they’re not the same as our awareness of being in the dream state. We no longer identify only with our dream ego—the “I” as dreamed—for our sense of self now includes our dreaming self: the “I” as dreamer. Similarly, while meditating in the waking state, we can simply witness being conscious and watch whatever sensory or mental events occur within the field of our awareness. We can also watch how we may identify with some of them as “Me” or appropriate some of them as “Mine.” According to the Indian yogic traditions, which broadly construed include Buddhism, we can distinguish three aspects of consciousness.2 The first aspect is awareness, the second is the contents of awareness, and the third is how we experience some of these contents of awareness as “I” or “Me” or “Mine.” From this perspective, to understand how we enact a self we need to understand three things—the nature [End Page 927] of awareness and its sensory and mental contents, the mind-body processes that produce these contents, and how some of these contents come to be experienced as “I” or “Me” or “Mine.” In Waking, Dreaming, Being, I take this threefold framework of awareness, contents of awareness, and self-experience—or what the Indian tradition calls “I-making” (ahaṃkāra)—and put it to work in cognitive science. Whereas the Indian thinkers mapped consciousness and I-making in philosophical and phenomenological terms, I show how their insights can also help to advance the neuroscience of consciousness by weaving together neuroscience and Indian philosophy in an exploration of wakefulness, falling asleep, dreaming, lucid dreaming, out-of-body experiences, deep and dreamless sleep, forms of meditative awareness, and the process of dying. The organizing principle for the book comes from the Indian tradition, specifically from the Upaniṣads, which arguably contain the world’s first recorded map of consciousness. The earliest texts—the Bṛhadāraṇyaka and Chāndogya Upaniṣads—delineate three principal states of the self—the waking state, the dream state, and the state of deep and dreamless sleep. The later text of the Māṇḍūkya Upaniṣad adds a fourth state...

Quantum Zeno Effect in Sleep Disorders and Treatment by the Anti-Zeno Effect

It is proposed on the basis of a recent quantum mechanical approach to the states of consciousness that for those sleep disorders of psychological origin which can be considered to be a Quantum Zeno Effect-type phenomenon of persistence in the waking state due to the inhibition of the transition to the Deep Sleep state, the treatment may very well lie in the application of the principle of accelerating the decay by the introduction of a third state which facilitates the transition as realized in the Quantum Anti-Zeno effect. Steps of practical therapeutic implementation of the program are delineated as an appendix.

40-Hz ASSR fusion classification system for observing sleep patterns.

This paper presents a fusion-based neural network (NN) classification algorithm for 40-Hz auditory steady state response (ASSR) ensemble averaged signals which were recorded from eight human subjects for observing sleep patterns (wakefulness W 0 and deep sleep N 3 or slow wave sleep SWS). In SWS, sensitivity to pain is the lowest relative to other sleep stages and arousal needs stronger stimuli. 40-Hz ASSR signals were extracted by averaging over 900 sweeps on a 30-s window. Signals generated during N 3 deep sleep state show similarities to those produced when general anesthesia is given to patients during clinical surgery. Our experimental results show that the automatic classification system used identifies sleep states with an accuracy rate of 100% when the training and test signals come from the same subjects while its accuracy is reduced to 97.6%, on average, when signals are used from different training and test subjects. Our results may lead to future classification of consciousness and wakefulness of patients with 40-Hz ASSR for observing the depth and effects of general anesthesia (DGA).

Comparison and Analysis of ONU Sleep Mechanism Based on OPNET for Green Fiber-Wireless Access Network

As one of promising "last mile" scheme for broadband access network, Fiber-Wireless (FiWi) access network has the advantages of high capacity, long distance, low cost etc because it is the integration of optical back-end and wireless front-end. At the same time, energy consumption of FiWi access network is an important factor that limits the development of networks. A number of ONU sleep states such as ONU power shedding state, ONU doze state, ONU deep sleep state and ONU fast sleep state have been proposed to obtain low-power ONU state, which indirectly reduce energy consumption of networks. However, these low-power states of ONU are born to coordinate to green Passive Optical Network (PON), of which the function of ONU is different from FiWi. In this paper, two low power ONU sleep mechanisms called Static ONU Sleep (SOS) mechanism and Dynamic ONU Sleep (DOS) mechanism, respectively, are proposed and embedded into FiWi access network. By simulation and analysis based on OPNET 14.5, this paper shows that the DOS mechanism has a better performance than SOS, and both of them can save energy of FiWi access network.

Quantifying Cortical EEG Responses to TMS in (Un)consciousness

We normally assess another individual's level of consciousness based on her or his ability to interact with the surrounding environment and communicate. Usually, if we observe purposeful behavior, appropriate responses to sensory inputs, and, above all, appropriate answers to questions, we can be reasonably sure that the person is conscious. However, we know that consciousness can be entirely within the brain, even in the absence of any interaction with the external world; this happens almost every night, while we dream. Yet, to this day, we lack an objective, dependable measure of the level of consciousness that is independent of processing sensory inputs and producing appropriate motor outputs. Theoretically, consciousness is thought to require the joint presence of functional integration and functional differentiation, otherwise defined as brain complexity. Here we review a series of recent studies in which Transcranial Magnetic Stimulation combined with electroencephalography (TMS/EEG) has been employed to quantify brain complexity in wakefulness and during physiological (sleep), pharmacological (anesthesia) and pathological (brain injury) loss of consciousness. These studies invariably show that the complexity of the cortical response to TMS collapses when consciousness is lost during deep sleep, anesthesia and vegetative state following severe brain injury, while it recovers when consciousness resurges in wakefulness, during dreaming, in the minimally conscious state or locked-in syndrome. The present paper will also focus on how this approach may contribute to unveiling the pathophysiology of disorders of consciousness affecting brain-injured patients. Finally, we will underline some crucial methodological aspects concerning TMS/EEG measurements of brain complexity.

Polysomnography (PSG) correlation in patients with moderate – severe OSAS at the time of diagnosis and after treatment with CPAP

Introduction Obstructive sleep apnea syndrome (OSAS) is a common and escalating health problem related to substantial morbidity and mortality. The use of continuous positive airway (CPAP) in most cases of OSAS has been proved that improves sleep quality, excessive daytime sleepiness (EDS) and quality of life. And it can also reduce morbidity and mortality in cardiovascular diseases, as well as consumption of healthcare resources. In our sleep unit we have tried to present the polysomnography correlation of patients submitted with diagnosis of moderate- severe OSAS before and after the treatment with CPAP. Materials and methods The study is based in a descriptive retrospective design. All patients were recruited from the sleep unit at the General Hospital of Alicante (Spain) including 130 patients during the years 2007–2012, previously diagnosed of OSAS, and we have compared the polysomnography before and after the treatment with CPAP. Data were obtained from review of all clinical records, patient and spouse questionnaires completed at the time of the original consultation, sleep study results, and objective CPAP use records. Patients taking antidepressants, hypnotics or benzodiazepines, with renal failure and hemodialysis or Chronic obstructive pulmonary disease (COPD) were excluded. Data were analyzed based on age, sex, BMC and comparative percentage of sleep phases and cycles. Results We analyzed 130 patients (104 male and 26 women), two studies per patient (at the diagnosis moment and post-treatment with CPAP; 260 PSG in total, middle age 51.3 years, 5% normal weight, 43% overweight and 50% obese. No significant difference was found between the groups; sex, age, BMI or the severity of the OSAS. Differences were found in the increase of percentage in the deep sleep state and REM sleep, specially in obese patients with severe OSAS. Conclusion The continued use of CPAP in obese patients with moderate and severe OSAS notably improves the sleep structure and therefore the quality of it. Acknowledgements Dr. Valentin Garcia and Dra. Francisca Selles. Thanks you for your help.

Prolonged daytime dissociative nrem3 sleep state in hypersomnolence with kleine levin symptomatology, a case report

Introduction We present a case of recurrent hypersomnolence. A diagnostic approach was performed. Materials and methods Medical evaluation by neurologist, ENT-surgeon, Maxillofacial surgeon, orthodontist and expert in sleep medicine and epilepsy. Results History: 7 weeks: stenosis pylori, 10th year: head injury; 41: Narcolepsy? HLADQ2 DQ8: neg.; negative effect of modafinil and sodium-oxybate; 41 years: IGM: Monoclonal Gammopathy of Undertermined Significance (MGUS). Symptoms: staring at childhood. At 42 years: 3 days a week hypersomnolence during daytime: sleeps from 12 am to 4 pm, a feeling of unreality, works at home on automatic pilot, has no recollection of what he has done for several hours. In this period he is highly emotional and irritated, is sexually hyper aroused and has changed eating habits, with vomiting, automatic behaviour during eating, dysbasia and atonic jerks during defecation. Neurology: no abnormalities. Polysomnography: daytime sleep 1:30–4 p.m.: deep sleep with steep sws during 40 min. Nighttime sleep 0–6.30 am; SE = 91%; awakenings 24; nrem3 = 111 min (30%); rem = 66 min (18.4%); apnea-hypopnea-index = 18.3/h. MSLT: SL = 4.1 min, no sorem. Two days EEG and video monitoring: at start and next morning a normal background EEG. At 0 pm headache, double vision, faster speaking, followed by automatic behaviour for 3 h in the late afternoon, without recollection. EEG: frontal intermittent delta activity, changing into diffuse slowing in EEG to 1–2/s. and frontal regions zeta waves 1–3 s. Magnetic resonance imaging: no abnormalities in gray and white matter. CSF fluid: Hypocretine-1: 362 ng/l (range 224–653); liquor ery: 0. 0 × 106/l;leu,5.0 × 106/l; gluc 3.3; total protein 0.51 g/l; virology: DNA HSV-1, HSV-2 and VZV: neg. Hormonal axis: GH:5.4 mU/l; TSH:1.88 mU/l; Cortisol; 8 a.m.:411; 4 p.m:157 nmol/l; ACTH:3.3 pmol/l; Testosteron: 13.4 nmol/l; Vit D: 30 nmol/l. Blood sample; BSE 4 mm/h; CRP Conclusion Diagnosis: Kleine–Levin syndrome, OSAS. No epilepsy. Treatment of OSAS with MRA was started and Vit D supplied. Therapy of KLS stabilizing deep and REM sleep during nighttime with Valproate 300–150 mg, zopiclon 7.5 mg; clonazepam 1 mg an; Mirtazapine 18 mgr an, followed by stimulating daytime vigilance with methylphenidate 10 mg 4 dd. Nighttime sleep improved to 7 h, daytime nap lessened to 2 h, dissociative deep sleep state in afternoon to 1/2 h. Conclusion: This case suggests a possible auto-immune mediation. Acknowledgements To the co-workers of the Department of Clinical Neurophysiology, Epilepsy and Sleep Centre SEIN Zwolle.

IS 24. TMS-EEG to measure excitability and connectivity of human cortical circuits

Recording TMS-evoked EEG potentials (TEPs) that are unconfounded by electromagnetic and biological artifacts is challenging. Neuronavigation guided TMS-EEG recordings performed in brain-injured patients showed that, when confounding factors are appropriately controlled, TMS elicits a significant EEG response only when is targeted on a scalp region overlying healthy cortical tissue and no response when is targeted over scalp areas overlying dead portions of the cortex while, in healthy subjects TEPs are highly reproducible over time. Thus, TEPs seem to purely reflect the response of the cortical tissue to TMS and can be used reliably to detect changes of excitability and connectivity in physiological, psychiatric and neurological conditions. For instance, in awake healthy subjects each cortical region tends to generate TEPs characterized by a dominant frequency (natural frequency) either when directly or indirectly activated by a TMS pulse. On the contrary, the tendency of different cortical circuits to oscillate at a specific frequency when directly perturbed is lost in schizophrenic patients. Most importantly, TMS-EEG measurements showed that effective connectivity is reduced during loss of consciousness in deep sleep, anesthesia and vegetative state. Interestingly, effective cortical connectivity recovered during REM sleep, and in acute brain injured patients before they could reestablish a functional communication with the environment. Overall, these observations suggest that TMS-EEG may represent a valuable tool to probe directly and non-invasively cortical excitability and connectivity in humans.

Science of self awareness and memory

The epistemological study and retrospection in fundamentals of sense perception and recollection is examined to understand the foundation of Memory. This analysis is done by a few simple tests from day to day experiences. With it, the well-known EEG signal data of individual's waking, dream and deep sleep states also analyzed. The examination establishes two fundamental discoveries: 1) A “Self induced” brain wave, having content related to old term “ego”, I, Me and Myself, which corresponds to “Self Awareness”; 2) Self awareness signal conversion into earlier received signal frequency. The study also determines that the human brain does not have any information of the natural composition of the physical world.

Subject-Object Duality and States of Consciousness: A Quantum Mechanical Approach

A phenomenological approach using the states of spin-like observables is developed to understand the nature of consciousness and the totality of experience. The three states of consciousness are taken to form the triplet of eigenstates of a spin-one entity and are derived as the triplet resulting from the composition of two spins by treating the subject and the object as interacting two-state, spin-half systems with external and internal projections. The state of deep sleep is analysed in the light of this phenomenological approach and a novel understanding of the status of the individual consciousness in this state is obtained. The resulting fourth state i.e. the singlet state, is interpreted to correspond to the superconscious state of intuitive experience and is justified by invoking the concept of the universal consciousness as the underlying source of all individual states of experience. It is proposed that the individual experiences result from the operations of four individualizing observables which project out the individual from the universal. The one-to-one correspondence between the individual and the universal states of experience is brought out and their identity in the fourth state is established by showing that all individualizing quantum numbers become zero in this state leaving no trace of any individuality.

Evaluation of sleep architecture in practitioners of Sudarshan Kriya yoga and Vipassana meditation

Yoga is an ancient Indian science and way of life that has been described in the traditional texts as a systematic method of achieving the highest possible functional harmony between body and mind. Yogic practices are claimed to enhance the quality of sleep. Electrophysiological correlates associated with the higher states of consciousness have been reported in long-term practitioners of transcendental meditation during deep sleep states. The present study was carried out to assess sleep architecture in Sudarshan Kriya Yoga (SKY) and Vipassana meditators. This was to ascertain the differences, if any, in sleep architecture following yogic practices. Whole night polysomnographic recordings were carried out in 78 healthy male subjects belonging to control and yoga groups. The groups studied were aged between 20 and 30-years-old (younger) and 31 to 55-years-old (middle-aged). The sleep architecture was comparable among the younger control and yoga groups. While slow wave sleep (non-REM (rapid eye movement) S3 and S4) had reduced to 3.7 percent in the middle-aged control group, participants of the middle-aged yoga groups (both SKY and Vipassana) showed no such decline in slow wave sleep states, which was experienced by 11.76 and 12.76 percent, respectively, of the SKY and Vipassana groups. However, Vipassana practitioners showed a significant enhancement (P < 0.001) in their REM sleep state from that of the age-matched control subjects and also from their SKY counterparts. Yoga practices help to retain slow wave sleep and enhance the REM sleep state in the middle age; they appear to retain a younger biological age as far as sleep is concerned. Overall, the study demonstrates the possible beneficial role of yoga in sleep-wakefulness behavior.

Optimizing sensor networks in the energy-latency-density design space

In wireless sensor networks, energy efficiency is crucial to achieving satisfactory network lifetime. To reduce the energy consumption significantly, a node should turn off its radio most of the time, except when it has to participate in data forwarding. We propose a new technique, called sparse topology and energy management (STEM), which efficiently wakes up nodes from a deep sleep state without the need for an ultra low-power radio. The designer can trade the energy efficiency of this sleep state for the latency associated with waking up the node. In addition, we integrate STEM with approaches that also leverage excess network density. We show that our hybrid wakeup scheme results in energy savings of over two orders of magnitude compared to sensor networks without topology management. Furthermore, the network designer is offered full flexibility in exploiting the energy-latency-density design space by selecting the appropriate parameter settings of our protocol.

Prediction of electroencephalographic spectra from neurophysiology.

A recent neurophysical model of propagation of electrical waves in the cortex is extended to include a physiologically motivated subcortical feedback loop via the thalamus. The electroencephalographic spectrum when the system is driven by white noise is then calculated analytically in terms of physiological parameters, including the effects of filtering of signals by the cerebrospinal fluid, skull, and scalp. The spectral power at low frequencies is found to vary as f(-1) when awake and f(-3) when asleep, with a breakpoint to a steeper power-law tail at frequencies above about 20 Hz in both cases; the f(-1) range concurs with recent magnetoencephalographic observations of such a regime. Parameter sensitivities are explored, enabling a model with fewer free parameters to be proposed, and showing that spectra predicted for physiologically reasonable parameter values strongly resemble those observed in the laboratory. Alpha and beta peaks seen near 10 Hz and twice that frequency, respectively, in the relaxed wakeful state are generated via subcortical feedback in this model, thereby leading to predictions of their frequencies in terms of physiological parameters, and of correlations in their occurrence. Subcortical feedback is also predicted to be responsible for production of anticorrelated peaks in deep sleep states that correspond to the occurrence of theta rhythm at around half the alpha frequency and sleep spindles at 3/2 times the alpha frequency. An additional positively correlated waking peak near three times the alpha frequency is also predicted and tentatively observed, as are two new types of sleep spindle near 5/2 and 7/2 times the alpha frequency, and anticorrelated with alpha. These results provide a theoretical basis for the conventional division of EEG spectra into frequency bands, but imply that the exact bounds of these bands depend on the individual. Three types of potential instability are found: one at zero frequency, another in the theta band at around half the alpha frequency, and a third at the alpha frequency itself.

Estados de comportamiento intraútero en los hijos de madres con diabetes tipo 1

ObjectiveTo establish to possible existence of differences in fetal neurological devolopment through analysis of the characteristics of fetal behavioral states in diabetic pregnancies Material and methodWe compared the results obtained in a control group, composed by 15 pregnant women with physiological pregnancy and another group composed by 15 pregnant women with type 1 diabetes. Gestacional age at the time of study was ≥ 37 and ≤ 41 weeks. Ocular activity, body movements and patterns of fetal cardiac frequency were sumultaneously recorder for 1 h using ultrasonography and kinetocardiography. The time spent by the fetuses in behavioral or coincident states, the ability to establish stable behavioral states and the number of changes in state (behavioral stability) were evaluated ResultsThe time spent by the fetuses in a state of deep sleep (F1) was significantly lower in the fetuses of diabetic women at 38 weeks' gestation. The duration of periods of behavioral incoordination (F5) was, in contrast, higner in this group and differences between groups were statustucally significant at 36-37 weeks. The number of changes in state was higher in the fetuses of diabetic women than in controls ConclusionsType 1 diabetes is associated with a lower ability to establish stable behavioral states in the fetuses of fiabetic mothers

Revelation in Islam

Abstract Among the world's religions, Islam has one of the most fully developed understandings of the notion of revelation. It views the whole of the created order as a revelation and, accordingly, considers religious revelation in the form of Scripture as an integral feature of the human condition. It is within this context that Muhammad's own revelatory experiences must be considered. These are well‐attested in the Hadith literature. Islam recognises three distinct grades of revelation. Muhammad's was the highest of these which, as the ahadith make clear, is a “passing into the deep sleep state in full consciousness ...”. The explicit nature of these traditional accounts of prophecy in action, as well as Islam's universalism, sheds light upon revelation in all religious traditions.

正弦波的振幅変調音による聴性定常反応

Auditory steady state responses elicited with sinusoidally amplitude-modulated tones of 0.5 to 4kHz were recorded in 9 adult subjects with normal hearing. The magnitude of the responses was greatest at 40-Hz modulation rate and at 90% modulation depth. The magnitude tended to decrease as a function of stimulus frequency. The lapse of time was measured from the minus peak of the amplitude-modulated tones to the following positive peak of the responses at the active electrode placed on the forehead just beneath the hairline. Its approximate values ranged between 12 and 15ms. The mean latency of the responses measured following Diamond Method was 12.2ms. A significant effect of sleep was found in the responses. The magnitude of the responses in deep sleep state frequently decreased less than 1/3 of that in awake state.

The effect of external stimuli on fetal behaviour.

The sensory receptors of the human fetus and their adequate stimulation are reviewed. Emphasis is put on the two main sensory routes through which the fetus may be stimulated: the hearing and the cutaneous senses. Most experimental and descriptive studies were done in these two well-defined areas. The core of the review deals with the description of sensory stimulation of the fetus as a function of the known behavioral states. It is postulated, and a series of experimental works cited in support, that reactions of the fetus to external stimuli, irrespective of the route through which they are presented, are subject to modulation by these states. It is proposed that an adequate stimulus in the normal, physiological range produces little or almost no effect in deep sleep (state 1 fetal) and does not change this state, whereas an inadequate stimulus which is strong ("painful") produces a definite change in state 1 fetal and is capable of triggering a change from state 1F to 2F (active sleep or rapid-eye-movement sleep).

Acute heroin abstinence in man: IV. Sleep--waking state contingencies.

This study investigated the effect of acute heroin withdrawal on the pattern of sleep--waking state sequences. Subjects included drug-dependent patients using pure heroin and drug-free controls. Electrophysiological data were recorded on a 24-hour per day basis for the first 5 - 7 days of withdrawal. EEG records were scored according to standard criteria. Marked increases in the sequential state changes occurred during withdrawal when progressing from awake-with-alpha, stage I, stage II and rapid eye movement (REM) sleep to the awake state. Heroin withdrawal also caused significant decreases in sequential state changes when proceeding from waking or light sleep states into deeper sleep states or into REM sleep. This study revealed that heroin withdrawal caused more abrupt transitions from quiet awake or sleeping conditions into the awake state and impeded progression into slow wave or REM sleep states.