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At least 19 recordsLinked to original sources

Sleep paralysis.

Sleep paralysis is a common condition with a prevalence of 5-62%. Although most affected people have single or infrequent episodes, sleep paralysis may be recurrent, or occur in association with the narcoleptic syndrome. In a study of 22 subjects with frequent sleep paralysis and also excessive daytime sleepiness, episodes continued for between 5 and 35 years. In contrast to subjects with the narcoleptic syndrome, these patients did not have cataplexy, daytime sleepiness and insomnia were less severe, and there was no HLA DR2(15) or DQ1(6) association. Sleep paralysis was familial in 19 of these subjects. A non-HLA linked genetic factor, in addition to environmental factors, may thus predispose to sleep paralysis.

Cataplexy↗

Personality of healthy young adults with sleep paralysis.

Sleep paralysis occurs in normal persons. This phenomenon had been studied psychoanalytically or in terms of the deviation of the victims' personality. This present study aimed to assess the personalities of such persons by using the MMPI and the Maudsley Personality Inventory. The subjects showed a slightly higher mean T score on the MMPI Paranoia Scale than those who did not have this experience. Although this personality difference might be related to the occurrence of the phenomenon, this difference is probably too small to take a major role. It is unlikely that the subjects developed paranoic behavior through their experiences of sleep paralysis, since their experiences were very few. Some of the subjects might have only overestimated their behavior and experiences concerning delusions and hallucinations, with the result that their Paranoia scores were higher and perhaps their kanashibari experiences exaggerated.

Adolescent↗

Isolated sleep paralysis elicited by sleep interruption.

We elicited isolated sleep paralysis (ISP) from normal subjects by a nocturnal sleep interruption schedule. On four experimental nights, 16 subjects had their sleep interrupted for 60 minutes by forced awakening at the time when 40 minutes of nonrapid eye movement (NREM) sleep had elapsed from the termination of rapid eye movement (REM) sleep in the first or third sleep cycle. This schedule produced a sleep onset REM period (SOREMP) after the interruption at a high rate of 71.9%. We succeeded in eliciting six episodes of ISP in the sleep interruptions performed (9.4%). All episodes of ISP except one occurred from SOREMP, indicating a close correlation between ISP and SOREMP. We recorded verbal reports about ISP experiences and recorded the polysomnogram (PSG) during ISP. All of the subjects with ISP experienced inability to move and were simultaneously aware of lying in the laboratory. All but one reported auditory/visual hallucinations and unpleasant emotions. PSG recordings during ISP were characterized by a REM/W stage dissociated state, i.e. abundant alpha electroencephalographs and persistence of muscle atonia shown by the tonic electromyogram. Judging from the PSG recordings, ISP differs from other dissociated states such as lucid dreaming, nocturnal panic attacks and REM sleep behavior disorders. We compare some of the sleep variables between ISP and non-ISP nights. We also discuss the similarities and differences between ISP and sleep paralysis in narcolepsy.

Adolescent↗

Questionnaire relating to sleep paralysis.

A sleep survey was conducted on 8162 citizens. The cumulative experience rate of sleep paralysis was 39.6%. The initial occurrence of sleep paralysis peaked at age 16 years. In addition to being higher in young people than in older subjects, the incidence of sleep paralysis was also higher among women than among men, and was significantly higher among shift worker than non-shift worker, and among persons engaged in the nursing profession than those not engaged in the nursing profession. The experience rate of sleep paralysis demonstrated a strong correlation with the frequency of dreaming, the experience rate of nightmares, times and regularity of going to bed and waking up, and particularly with the degree of insomnia.

Adolescent↗

Sleep paralysis among medical students.

Sleep paralysis is a sensation of an inability to speak or move other muscles when falling asleep or awakening. Sleep paralysis by itself has been reported as occurring infrequently and many clinicians are uncertain of its significance. In contrast, sleep paralysis in conjunction with sleep attacks has been reported as a concomitant of narcolepsy. To further examine the incidence of sleep paralysis, the responses of 80 first-year medical students, 16.25% had experienced predormital, postdormital, or both types of sleep paralysis. These episodes occurred infrequently--only once or twice for most of these students. Reports of sleep paralysis were not associated with sleep attacks or cataplexy. These results support two previous studies which found that sleep paralysis alone occurs frequently among normals.

Adult↗

Relations among hypnagogic and hypnopompic experiences associated with sleep paralysis.

The Waterloo Sleep Experiences Scale was developed to assess the prevalence of sleep paralysis and a variety of associated hypnagogic and hypnopompic hallucinoid experiences: sensed presence, felt pressure, floating sensations, auditory and visual hallucinations, and fear. Consistent with results of recent surveys, almost 30% of 870 university students reported at least one experience of sleep paralysis. Approximately three-quarters of those also reported at least one hallucinoid experience, and slightly more than 10% experienced three or more. Fear was positively associated with hallucinoid experiences, most clearly with sensed presence. Regression analyses lend support to the hypothesis that sensed presence and fear are primitive associates of sleep paralysis and contribute to the elaboration of further hallucinoid experiences, especially those involving visual experiences.

Adult↗

Sleep paralysis and hallucinosis.

Background: Sleep paralysis is one of the many conditions of which visual hallucinations can be a part but has received relatively little attention. It can be associated with other dramatic symptoms of a psychotic nature likely to cause diagnostic uncertainty. Methods and results: These points are illustrated by the case of a young man with a severe bipolar affective disorder who independently developed terrifying visual, auditory and somatic hallucinatory episodes at sleep onset, associated with a sense of evil influence and presence. The episodes were not obviously related to his psychiatric disorder. Past diagnoses included nightmares and night terrors. Review provided no convincing evidence of various other sleep disorders nor physical conditions in which hallucinatory experiences can occur. A diagnosis of predormital isolated sleep paralysis was made and appropriate treatment recommended. Conclusions: Sleep paralysis, common in the general population, can be associated with dramatic auxiliary symptoms suggestive of a psychotic state. Less common forms are either part of the narcolepsy syndrome or (rarely) they are familial in type. Interestingly, sleep paralysis (especially breathing difficulty) features prominently in the folklore of various countries.

Journal Article↗

Resolution of sleep paralysis by weak electromagnetic fields in a patient with multiple sclerosis.

Sleep paralysis refers to episodes of inability to move during the onset of sleep or more commonly upon awakening. Patients often describe the sensation of struggling to move and may experience simultaneous frightening vivid hallucinations and dreams. Sleep paralysis and other manifestations of dissociated states of wakefulness and sleep, which reflect deficient monoaminergic regulation of neural modulators of REM sleep, have been reported in patients with multiple sclerosis (MS). A 40 year old woman with remitting-progressive multiple sclerosis (MS) experienced episodes of sleep paralysis since the age of 16, four years prior to the onset of her neurological symptoms. Episodes of sleep paralysis, which manifested at a frequency of about once a week, occurred only upon awakening in the morning and were considered by the patient as a most terrifying experience. Periods of mental stress, sleep deprivation, physical fatigue and exacerbation of MS symptoms appeared to enhance the occurrence of sleep paralysis. In July of 1992 the patient began experimental treatment with AC pulsed applications of picotesla intensity electromagnetic fields (EMFs) of 5Hz frequency which were applied extracerebrally 1-2 times per week. During the course of treatment with EMFs the patient made a dramatic recovery of symptoms with improvement in vision, mobility, balance, bladder control, fatigue and short term memory. In addition, her baseline pattern reversal visual evoked potential studies, which showed abnormally prolonged latencies in both eyes, normalized 3 weeks after the initiation of magnetic therapy and remained normal more than 2.5 years later. Since the introduction of magnetic therapy episodes of sleep paralysis gradually diminished and abated completely over the past 3 years. This report suggests that MS may be associated with deficient REM sleep inhibitory neural mechanisms leading to sleep paralysis secondary to the intrusion of REM sleep atonia and dream imagery into the waking state. Pineal melatonin and monoaminergic neurons have been implicated in the induction and maintenance of REM sleep and the pathogenesis of sleep paralysis and it is suggested that resolution of sleep paralysis in this patient by AC pulsed applications of EMFs was related to enhancement of melatonin circadian rhythms and cerebral serotoninergic neurotransmission.

Adult↗

Factors related to the occurrence of isolated sleep paralysis elicited during a multi-phasic sleep-wake schedule.

STUDY OBJECTIVES: To further investigate mechanisms of isolated sleep paralysis (ISP) in normal individuals, we experimentally elicited ISPs by facilitating sleep onset REM periods (SOREMP), a prerequisite of ISPs, and examined behavioral and psychological measurements relating to ISP appearances. DESIGN: The multi-phasic sleep/wake schedule (MPS) began at approximately midnight and ended when net sleep reached 7.5 hours. Participants were awakened after every 5 min of REM sleep to obtain a maximum number of SOREMPs. Upon each awakening, mentation reports and subjective measurements were collected. Performance tests were then assigned. SETTING: Sleep lab, Tokyo Metropolitan Institute for Neurosciences, Japan. PARTICIPANTS: Thirteen healthy Japanese students (10 males) with high self-reported frequencies of ISPs but no other narcolepsy-related symptoms. INTERVENTIONS MEASUREMENTS AND RESULTS: From 184 sleep interruptions, 8 ISP episodes were obtained. In within participant comparisons between episodes with and without ISPs, the vigilance task (VT) reaction times were elevated before SOREMPs with ISPs. In between analyses (ISP vs non-ISP), the ISP group showed poorer performance, more complaints of physical, mental, and neurotic symptoms, increased subjective fatigue and increased stage 1 throughout the entire schedule. VT hit rates remained constant in the non-ISP group, but dropped in the later part of schedule in the ISP group. Subjective sleepiness dropped over time in the non-ISP group while it slightly increased in the ISP group. CONCLUSIONS: ISP is likely to appear as a phenotype of REM dissociation during SOREMP when participants with low tolerance for disrupted sleep-wake rhythms are placed in this type of schedule.

Adult↗

Physiology of REM sleep, cataplexy, and sleep paralysis.

The main neural structures generating muscle atonia and other phenomena characteristic of REM sleep are present in dorsolateral portions of the pons in the brainstem. Occurrence of REM sleep and the NREM-REM sleep cycle are probably determined by a balance or interaction between the cholinergic and cholinoceptive REM sleep-on neuronal populations and the monoaminergic REM sleep-off neuronal population. Neural activities producing generalized muscle atonia in REM sleep originate mainly in dorsolateral portions of the pontine reticular formation, descend through the medulla and spinal cord, and inhibit the motoneurons in the brainstem and spinal cord, bringing about postural atonia. Cataplexy and sleep paralysis are pathological, dissociated manifestations of the generalized muscle atonia characteristic REM sleep. Cataplexy is triggered by emotional stimuli, probably through activation of the neural structure generating the muscle atonia of REM sleep. During long-lasting cataplectic attacks, narcoleptic humans often experience sleep paralysis and vivid hypnagogic hallucinations in the latter sleep state. Sleep paralysis is caused by the marked dissociation between level of alertness and muscle atonia that often occurs in SOREM sleep episodes. Frequent SOREM sleep episodes in narcoleptic humans and dogs may occur when some of the neural mechanisms producing wakefulness and/or NREM sleep that normally inhibit the occurrence of REM sleep are abnormally weak, or when neural mechanisms facilitating the occurrence of REM sleep are hypersensitive or hyperactive, or both. Both abnormalities may contribute to the occurrence of SOREM sleep episodes and sleep paralysis, and also to the emotional triggering of cataplexy. Frequent occurrence of SOREM sleep episodes seems to be prerequisite but not sufficient for the occurrence of cataplexy. Some additional neural activities induced by emotion also contribute by inhibiting and/or activating the disturbed neural mechanisms related to SOREM sleep episodes. These abnormalities in neural mechanisms probably involve hypersensitivity or hyperactivity of muscarinic cholinergic and/or cholinoceptive neuronal populations in the pontine and suprapontine structures, and/or abnormally decreased activity of noradrenergic or serotonergic neuronal populations in the pons and/or other brainstem structures. This last monoaminergic neuronal population probably has a gating or inhibiting effect upon the cholinergic and cholinoceptive neuronal populations related to the generation of generalized muscle atonia and REM sleep. In spite of many studies and published reports on REM sleep, as well as on cataplexy and sleep paralysis, we are still far from a complete understanding of the physiological mechanisms producing muscle atonia in REM sleep and of the pathophysiological mechanisms of cataplexy and sleep paralysis--though it is apparent that these mechanisms are closely related.

Animals↗

Prevalence of isolated sleep paralysis in black subjects.

Sleep paralysis is a state of consciousness experienced while waking from sleep or falling asleep. It is characterized by an experience of being unable to move for several seconds or minutes. This study represents the first survey to measure the incidence of this disorder in a black population of healthy subjects and psychiatric patients.

Adult↗

Situational factors affecting sleep paralysis and associated hallucinations: position and timing effects.

Sleep paralysis (SP) entails a period of paralysis upon waking or falling asleep and is often accompanied by terrifying hallucinations. Two situational conditions for sleep paralysis, body position (supine, prone, and left or right lateral decubitus) and timing (beginning, middle, or end of sleep), were investigated in two studies involving 6730 subjects, including 4699 SP experients. A greater number of individuals reported SP in the supine position than all other positions combined. The supine position was also 3-4 times more common during SP than when normally falling asleep. The supine position during SP was reported to be more prevalent at the middle and end of sleep than at the beginning suggesting that the SP episodes at the later times might arise from brief microarousals during REM, possibly induced by apnea. Reported frequency of SP was also greater among those consistently reporting episodes at the beginning and middle of sleep than among those reporting episodes when waking up at the end of sleep. The effects of position and timing of SP on the nature of hallucinations that accompany SP were also examined. Modest effects were found for SP timing, but not body position, and the reported intensity of hallucinations and fear during SP. Thus, body position and timing of SP episodes appear to affect both the incidence and, to a lesser extent, the quality of the SP experience.

Adult↗

Sleep paralysis in the elderly.

Isolated sleep paralysis (SP) is a common sleep phenomenon that is highly colored by indigenous beliefs. In Hong Kong Chinese, the 'ghost oppression phenomenon' (GO) has been shown to be descriptively identical to SP. The prevailing concept is that the majority of cases with SP have their onset during adolescence, but the lack of any systematic study on an older population means that late-onset cases can not be excluded. In a study investigating the prevalence of mental disorders in Chinese elderly aged above 70 y in Hong Kong, we employed the revised GO questionnaire to study the prevalence of SP in this group of elderly as well. One hundred and fifty-eight subjects were finally analyzed for the study. Almost 18% (95% C.I. 11.77%, 23.68%) of the subjects reported experiences of GO. Their description of the features of GO showed striking similarity to those of SP. There was a clear bimodal distribution of onset of GO with peaks during adolescence and after age 60 y. At least one-third of the cases were late onset. In concordance with the rapid eye movement (REM)/wakefulness dissociation hypothesis of SP, those elderly with GO+ experiences also had more frequent nocturnal sleep disturbances. A family history was reported in 10% of subjects.

Age of Onset↗

Further studies on the prevalence of isolated sleep paralysis in black subjects.

In a previous study, one of the authors (C.C.B.) found isolated sleep paralysis was common in blacks. In this study, conducted by interviews, a recurrent pattern (one or more episodes per month) of isolated sleep paralysis episodes in blacks was described by at least 25 percent of the afflicted sample studied. Frequent episodes were associated with stress, and subjects with isolated sleep paralysis had an unusually high prevalence of panic disorder (15.5 percent). The genetic transmission of sleep paralysis was studied in a large black family, and in addition to stressful environmental factors being associated with the condition, there appears to be a dominant genetic factor associated with the predisposition for developing sleep paralysis. The implications of these findings for stress, anxiety, sleep, and psychophysiologic disorders are discussed.

Adult↗

Isolated sleep paralysis: a web survey.

Isolated Sleep Paralysis (SP) occurs at least once in a lifetime in 40-50% of normal subjects, while as a chronic complaint it is an uncommon and scarcely known disorder. A series of messages written by subjects who experienced at least one episode of SP, containing more or less detailed descriptions of this disorder, were collected from the Sleep Web site of the University of California in Los Angeles between January 1996 and July 1998. Two hundred and sixty-four messages fulfilling the International Classification of Sleep Disorders (ICSD) (Thorpy, 1990) minimal criteria for SP were analyzed. A wide spectrum of severity was evident, with a frequency of episodes ranging from one in a lifetime to almost every night, and a variety of emotional and hallucinatory experiences associated with SP episodes were reported. Clinical similarities between the recurrent form of isolated SP and channelopathies (in particular, periodic paralyses) are discussed. An activation of limbic system structures is suggested in order to explain some of the most common subjective experiences associated with SP.

Adolescent↗