Narcolepsy Severity Scale-2 and Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and consequences in Narcolepsy type 2.

STUDY OBJECTIVES: Narcolepsy type 2 (NT2) is an understudied central disorder of hypersomnolence sharing some similarities with narcolepsy type 1 and idiopathic hypersomnia (IH). We aimed: (1) to assess systematically the symptoms in patients with NT2, with self-reported questionnaires: Epworth Sleepiness Scale (ESS), Narcolepsy Severity Scale (NSS), IH Severity Scale (IHSS), and (2) to evaluate the responsiveness of these scales to treatment. METHODS: One hundred and nine patients with NT2 (31.4 ±â€…12.2 years old, 47 untreated) diagnosed according to ICSD-3 were selected in a Reference Center for Narcolepsy. They all completed the ESS, subgroups completed the modified NSS (NSS-2, without cataplexy items) (n = 95) and IHSS (n = 76). Some patients completed the scales twice (before/during treatment): 42 ESS, 26 NSS-2, and 30 IHSS. RESULTS: Based on NSS-2, all untreated patients had sleepiness, 58% disrupted nocturnal sleep, 40% hallucinations, and 28% sleep paralysis. On IHSS, 76% reported a prolonged nocturnal sleep, and 83% sleep inertia. In the independent sample, ESS and NSS-2 scores were lower in treated patients, with same trend for IHSS scores. After treatment, ESS, NSS-2, and IHSS total scores were lower, with a mean difference of 3.7 ±â€…4.1, 5.3 ±â€…6.7, and 4.1 ±â€…6.2, respectively. The minimum clinically important difference between untreated and treated patients were 2.1 for ESS, 3.3 for NSS-2, and 3.1 for IHSS. After treatment, 61.9% of patients decreased their ESS > 2 points, 61.5% their NSS-2 > 3 points, and 53.3% their IHSS > 3 points. CONCLUSIONS: NSS-2 and IHSS correctly quantified symptoms' severity and consequences in NT2, with good performances to objectify response to medications. These tools are useful for monitoring and optimizing NT2 management, and for use in clinical trials.

Nightmare Disorder and Isolated Sleep Paralysis.

Nightmare disorder and recurrent isolated sleep paralysis are rapid eye movement (REM) parasomnias that cause significant distress to those who suffer from them. Nightmare disorder can cause insomnia due to fear of falling asleep through dread of nightmare occurrence. Hyperarousal and impaired fear extinction are involved in nightmare generation, as well as brain areas involved in emotion regulation. Nightmare disorder is particularly frequent in psychiatric disorders and posttraumatic stress disorder. Nonmedication treatment, in particular imagery rehearsal therapy, is especially effective. Isolated sleep paralysis is experienced at least once by up to 40% of the general population, whereas recurrence is less frequent. Isolated sleep paralysis can be accompanied by very intense and vivid hallucinations. Sleep paralysis represents a dissociated state, with persistence of REM atonia into wakefulness. Variations in circadian rhythm genes might be involved in their pathogenesis. Predisposing factors include sleep deprivation, irregular sleep-wake schedules, and jetlag. The most effective therapy consists of avoiding those factors.

Clinical features of isolated sleep paralysis.

OBJECTIVE: Isolated sleep paralysis (ISP) is a relatively common parasomnia often accompanied by fear and distress. However, little is known about the range and relative severities of typical ISP symptoms and accompanying hallucinations. Furthermore, there have been inconsistent findings with regard to demographic differences in ISP. PATIENTS/METHOD: In sum, 185 individuals with ISP (and 322 controls) were assessed for 27 symptoms and hallucinations using a clinical interview and trained diagnosticians. Insomnia symptoms were also assessed. RESULTS: Rates of ISP did not differ according to gender or ethnic minority status, but higher levels of insomnia were associated with episodes. The participants with ISP reported a mean of 7.73 symptoms beyond atonia. Hallucinations of the presence of others were relatively common. Specifically, 57.84% of the sample sensed a presence in the room with them during ISP, and the majority believed it to be a non-human presence. In addition, 21.62% of the sample experienced visual hallucinations of others, with the majority perceiving strangers as opposed to known individuals. A panoply of supernatural/paranormal entities were reported by the 24.32% of participants who hallucinated non-human beings. A minority of individuals with ISP experienced clinically-significant distress (10.27%) and/or impairment (7.57%) as a result of episodes. CONCLUSION: ISP episodes were complex and often multisensorial experiences, and the majority of assessed symptoms were associated with clinically-significant levels of fear/distress. Vivid hallucinations of other people and entities were common as well, and it is recommended that ISP be assessed when patients report seemingly anomalous experiences.

The inappropriate occurrence of rapid eye movement sleep in narcolepsy is not due to a defect in homeostatic regulation of rapid eye movement sleep.

Narcolepsy type 1 is a disabling disorder with four primary symptoms: excessive-daytime-sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. The later three symptoms together with a short rapid eye movement (REM) sleep latency have suggested impairment in REM sleep homeostatic regulation with an enhanced propensity for (i.e. tendency to enter) REM sleep. To test this hypothesis, we challenged REM sleep homeostatic regulation in a recognized model of narcolepsy, the orexin knock-out (Orex-KO) mice and their wild-type (WT) littermates. We first performed 48 hr of REM sleep deprivation using the classic small-platforms-over-water method. We found that narcoleptic mice are similarly REM sleep deprived to WT mice. Although they had shorter sleep latency, Orex-KO mice recovered similarly to WT during the following 10 hr of recovery. Interestingly, Orex-KO mice also had cataplexy episodes immediately after REM sleep deprivation, anticipating REM sleep rebound, at a time of day when cataplexy does not occur in baseline condition. We then evaluated REM sleep propensity using our new automated method of deprivation that performs a specific and efficient REM sleep deprivation. We showed that REM sleep propensity is similar during light phase in Orex-KO and WT mice. However, during the dark phase, REM sleep propensity was not suppressed in Orex-KO mice when hypocretin/orexin neuropeptides are normally released. Altogether our data suggest that in addition to the well-known wake-promoting role of hypocretin/orexin, these neuropeptides would also suppress REM sleep. Therefore, hypocretin/orexin deficiency would facilitate the occurrence of REM sleep at any time of day in an opportunistic manner as seen in human narcolepsy.

Terror and bliss? Commonalities and distinctions between sleep paralysis, lucid dreaming, and their associations with waking life experiences.

Sleep paralysis and lucid dreaming are both dissociated experiences related to rapid eye movement (REM) sleep. Anecdotal evidence suggests that episodes of sleep paralysis and lucid dreaming are related but different experiences. In this study we test this claim systematically for the first time in an online survey with 1928 participants (age range: 18-82 years; 53% female). Confirming anecdotal evidence, sleep paralysis and lucid dreaming frequency were related positively and this association was most apparent between lucid dreaming and sleep paralysis episodes featuring vestibular-motor hallucinations. Dissociative experiences were the only common (positive) predictor of both sleep paralysis and lucid dreaming. Both experiences showed different associations with other key variables of interest: sleep paralysis was predicted by sleep quality, anxiety and life stress, whereas lucid dreaming was predicted by a positive constructive daydreaming style and vividness of sensory imagery. Overall, results suggest that dissociative experiences during wakefulness are reflected in dissociative experiences during REM sleep; while sleep paralysis is related primarily to issues of sleep quality and wellbeing, lucid dreaming may reflect a continuation of greater imaginative capacity and positive imagery in waking states.

Sleep paralysis and "the bedroom intruder": the role of the right superior parietal, phantom pain and body image projection.

Sleep paralysis (SP) is a common condition occurring either at sleep onset or sleep offset. During SP the sleeper experiences gross motor paralysis while the sensory system is clear. Hypnogogic and hypnopompic hallucinations are common during SP and may involve seeing, hearing, and sensing the presence of menacing intruders in one's bedroom. This "intruder" is often perceived as a shadowy humanoid figure. Supernatural accounts of this hallucinated intruder are common across cultures. In this paper, we postulate that a functional disturbance of the right parietal cortex explains the shadowy nocturnal bedroom intruder hallucination during SP. This hallucination may arise due to a disturbance in the multisensory processing of body and self at the temporoparietal junction. We specifically propose that this perceived intruder is the result of a hallucinated projection of the genetically "hard-wired" body image (homunculus), in the right parietal region; namely, the same circuits that dictate aesthetic and sexual preference of body morphology. One way to test this hypothesis would be to study clinical populations who may have genetically acquired "irregularities" in their internal hard-wired body image in the right superior parietal lobule (SPL); for example, individuals with apotemnophilia or anorexia nervosa. If such individuals experience SP (e.g., induced in a sleep lab), and they hallucinate this shadowy figure, one would predict that they would see humanoid shadows and shapes with body irregularities, mirroring their own internal body image morphology. If correct, our hypothesis will offer a neurological explanation for this nocturnal bedroom intruder that has been a source of controversy, and striking and implausible cultural interpretations throughout history. Indeed, if our proposed hypothesis is tested and corroborated, dissemination of such findings would provide great relief to SP experiencers worldwide and could potentially be used in a therapeutic context.

Rates and characteristics of sleep paralysis in the general population of Denmark and Egypt.

In the current research we report data from two studies that examined rates and characteristics of sleep paralysis (SP) in the general population of Denmark and Egypt. In Study I, individuals from Denmark and Egypt did not differ in age whereas there were more males in the Egyptian sample (47 vs. 64 %); in Study II, individuals from Denmark and Egypt were comparable in terms of age and gender distribution. In Study I we found that significantly fewer individuals had experienced SP in Denmark [25 % (56/223)] than in Egypt [44 % (207/470)] p < .001. In Study II we found that individuals who had experienced at least one lifetime episode of SP from Denmark (n = 58) as compared to those from Egypt (n = 143) reported significantly fewer SP episodes in a lifetime relative to SP experiencers from Egypt (M = 6.0 vs. M = 19.4, p < .001). SP in the Egyptian sample was characterized by high rates of SP (as compared to in Denmark), frequent occurrences (three times that in the Denmark sample), prolonged immobility during SP, and great fear of dying from the experience. In addition, in Egypt, believing SP to be precipitated by the supernatural was associated with fear of the experience and longer SP immobility. Findings are discussed in the context of cultural elaboration and salience theories of SP.

Sleep paralysis in narcolepsy: more than just a motor dissociative phenomenon?

Sleep paralyses are viewed as pure motor phenomena featured by a dissociated state in which REM-related muscle atonia coexists with a wakefulness state of full consciousness. We present a 59-year-old man diagnosed with narcolepsy experiencing sleep paralysis, who failed to establish the boundaries between real experience and dream mentation during the paralysis: the patient's recall was indeed featured by uncertainty between real/unreal and awaken/dreaming. Hereby, we suggest that sleep paralysis may represent a more complex condition encompassing a dissociated state of mind together with the dissociative motor component. Neurophysiological data (spectral EEG analysis corroborated by cross-correlation analysis) reinforce the idea that the patient was in an intermediate state of mind between wake and REM sleep during the paralysis. The persistence of local impaired activity proper of REM sleep in cortical circuits necessary for self-reflective awareness and insight, in conflict with wakefulness-related activation of the remaining brain areas, could account for disrupted processing of afferent inputs in our patient, representing the underlying pathophysiologic substrate for patient's failure to establish the boundaries between real experience and dream mentation.

Autonomic disturbances in narcolepsy.

Narcolepsy is a clinical condition characterized mainly by excessive sleepiness and cataplexy. Hypnagogic hallucinations and sleep paralysis complete the narcoleptic tetrad; disrupted night sleep, automatic behaviors and weight gain are also usual complaints. Different studies focus on autonomic changes or dysfunctions among narcoleptic patients, such as pupillary abnormalities, fainting spells, erectile dysfunction, night sweats, gastric problems, low body temperature, systemic hypotension, dry mouth, heart palpitations, headache and extremities dysthermia. Even if many studies lack sufficient standardization or their results have not been replicated, a non-secondary involvement of the autonomic nervous system in narcolepsy is strongly suggested, mainly by metabolic and cardiovascular findings. Furthermore, the recent discovery of a high risk for overweight and for metabolic syndrome in narcoleptic patients represents an important warning for clinicians in order to monitor and follow them up for their autonomic functions. We review here studies on autonomic functions and clinical disturbances in narcoleptic patients, trying to shed light on the possible contribute of alterations of the hypocretin system in autonomic pathophysiology.

Isolated sleep paralysis linked to impaired nocturnal sleep quality and health-related quality of life in Chinese-Taiwanese patients with obstructive sleep apnea.

PURPOSE: Isolated sleep paralysis (ISP) is a rapid eye movement (REM) sleep parasomnia and has a special meaning in Chinese population. Worsening of obstructive sleep apnea (OSA) occurs especially during REM sleep. The relationship between ISP and OSA is unclear. The aim of this study was to investigate the impact of ISP on sleep and life quality in Chinese-Taiwanese OSA patients. METHODS: We recruited 107 OSA patients diagnosed by polysomnography (PSG) in Southern Taiwan. ISP was evaluated by self-reported sleep questionnaire. We used Chinese version of Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Short-Form 36 (SF36) to evaluate daytime sleepiness, nocturnal sleep quality, and health-related quality of life, respectively for OSA patients. Student's t-test was used to compare PSG parameters, ESS, PSQI, physical and mental component of SF-36 (P-SF36 and M-SF36) between OSA patients with and without ISP. Stepwise multiple regression was used to find out the factors independently associated with ESS, PSQI, P-SF36, and M-SF36. RESULTS: Forty-one of 107 patients (38.3%) had ISP. It showed no significant difference in PSG parameters between OSA patients with and without ISP. OSA patients with ISP had significantly higher ESS (P = 0.010), higher PSQI (P = 0.007), lower P-SF36 (P = 0.020), and lower M-SF36 (P = 0.001) than those without ISP. ISP was an independent factor associated with ESS (P = 0.017), PSQI (P = 0.001), and M-SF36 (P = 0.030) after adjusting for other confounding variables. CONCLUSIONS: ISP was independently associated with excessive daytime sleepiness, worse sleep quality, and impaired mental health-related quality of life in Chinese-Taiwanese OSA patients.

Lifetime prevalence and incidence of parasomnias in a population of young adult Nigerians.

Lifetime prevalence, incidence, and risk factors for parasomnias were determined. Past experiences of non-REM, REM, and sleep-transition parasomnias were recorded. Diaries of night sleep duration, parasomnias, perception of aliens, levels of physical activity, headaches and intake of all substances, drugs, and tobacco were kept for 14 consecutive days. A total of 276 subjects were studied. Lifetime prevalences (95% CI) were 725 (668-776) for occurrence of any parasomnia, 43 (25-74) for sleepwalking, 112 (80-155) for sleep terror, 475 (416-533) for nightmares, 225 (179-277) for sleep paralysis, 43 (25-74) for sleep starts, 322 (270-380) for sleep talking, and 344 (291-402) for enuresis. Incidences (95% CI) were 210 (166-262) for occurrence of any parasomnia, 14 (6-37) for sleepwalking, 11 (4-31) for sleep terror, 170 (131-219) for confusional arousal, 18 (8-42) for nightmares, 14 (6-37) for sleep paralysis, 33 (17-61) for sleep starts, and 4 (1-20) for sleep enuresis. Multivariate analysis showed associations of increase occurrence of parasomnias and duration of sleep >7 h (p < 0.05) and intake of alcohol (p < 0.001), but heavy workload before sleep was associated with decreased occurrence of parasomnias (p < 0.01). Gender, smoking, caffeinated drinks, hypnotics, and headaches were not associated with parasomnias. Incidence of presence of aliens (95% CI) in the room was 25(0/infinity) (12-51). This study shows that more than 70% of the population have experienced parasomnias at any time in the past. Nightmares, enuresis, sleep paralysis and night terrors are the commonest parasomnias experienced in the past, while confusional arousal, sleep starts, and nightmares are the commonest parasomnias currently experienced. Incidence estimates show that all parasomnias persist into adulthood at reduced rates, but reduction of occurrence was greatest for enuresis. Long duration of night sleep and intake of alcohol predisposed subjects to higher occurrence of parasomnias.

The body unbound: vestibular-motor hallucinations and out-of-body experiences.

Among the varied hallucinations associated with sleep paralysis (SP), out-of-body experiences (OBEs) and vestibular-motor (V-M) sensations represent a distinct factor. Recent studies of direct stimulation of vestibular cortex report a virtually identical set of bodily-self hallucinations. Both programs of research agree on numerous details of OBEs and V-M experiences and suggest similar hypotheses concerning their association. In the present study, self-report data from two on-line surveys of SP-related experiences were employed to assess hypotheses concerning the causal structure of relations among V-M experiences and OBEs during SP episodes. The results complement neurophysiological evidence and are consistent with the hypothesis that OBEs represent a breakdown in the normal binding of bodily-self sensations and suggest that out-of-body feelings (OBFs) are consequences of anomalous V-M experiences and precursors to a particular form of autoscopic experience, out-of-body autoscopy (OBA). An additional finding was that vestibular and motor experiences make relatively independent contributions to OBE variance. Although OBEs are superficially consistent with universal dualistic and supernatural intuitions about the nature of the soul and its relation to the body, recent research increasingly offers plausible alternative naturalistic explanations of the relevant phenomenology.

[Sleep and movement disorders]. / Schlaf und Bewegungsstörungen.

The three different states of being (wakefulness, NREM and REM sleep) are associated with profound neurophysiological and neurochemical changes in the brain. These changes explain the existence of movement disorders appearing only or preferentially during sleep, and the effects of sleep on movement disorders. Sleep-related movement disorders are of clinical relevance for multiple reasons: 1) high frequency (e.g. restless legs syndrome (RLS)); 2) diagnostic relevance (e.g. REM sleep behavior disorder (RBD) as first manifestation of Parkinson disorder); 3) diagnostic uncertainty (e.g. parasomnias vs nocturnal epilepsy); 4) association with injuries (e.g. RBD, sleepwalking), sleep disruption/daytime sleepiness (e.g. RLS), and psycho-social burden (e.g. enuresis); 5) requirement of specific treatments (e.g. nocturnal epilepsy, stridor, RBD). This article gives an overview on clinical manifestations, pathophysiology, work-up and treatment of sleep-related movement disorders (e.g. RLS, bruxism), parasomnias (e.g. sleepwalking, RBD), sleep-related epilepsies, and on sleep-associated manifestations of movement disorders (e.g. Parkinson disease, multiple system atrophy).

Timing of spontaneous sleep-paralysis episodes.

The objective of this prospective naturalistic field study was to determine the distribution of naturally occurring sleep-paralysis (SP) episodes over the course of nocturnal sleep and their relation to bedtimes. Regular SP experiencers (N = 348) who had previously filled out a screening assessment for SP as well as a general sleep survey were recruited. Participants reported, online over the World Wide Web, using a standard reporting form, bedtimes and subsequent latencies of spontaneous episodes of SP occurring in their homes shortly after their occurrence. The distribution of SP episodes over nights was skewed to the first 2 h following bedtime. Just over one quarter of SP episodes occurred within 1 h of bedtime, although episodes were reported throughout the night with a minor mode around the time of normal waking. SP latencies following bedtimes were moderately consistent across episodes and independent of bedtimes. Additionally, profiles of SP latencies validated self-reported hypnagogic, hypnomesic, and hypnopompic SP categories, as occurring near the beginning, middle, and end of the night/sleep period respectively. Results are consistent with the hypothesis that SP timing is controlled by mechanisms initiated at or following sleep onset. These results also suggest that SP, rather than uniquely reflecting anomalous sleep-onset rapid eye movement (REM) periods, may result from failure to maintain sleep during REM periods at any point during the sleep period. On this view, SP may sometimes reflect the maintenance of REM consciousness when waking and SP hallucinations the continuation of dream experiences into waking life.

Exploding head syndrome followed by sleep paralysis: a rare migraine aura.

A 26-year-old patient is described with a unique migraine aura. She described an 8-year history of episodes occurring 1 to 2 times yearly of exploding head syndrome followed by sleep paralysis followed by a migraine headache. She also had identical headaches without aura about once per week. Both aura symptoms, which may occur in the brainstem, resulted in activation of the trigeminovascular system through an unknown mechanism.

Conditions of primary excessive daytime sleepiness.

Excessive daytime somnolence is a prevalent problem in medical practice and in society. It exacts a great toll in quality of life, personal and public safety, and productivity. The causes of EDS are myriad, and careful evaluation is needed to determine the cause in each case. Although much progress has been made in discovering the pathophysiology of narcolepsy, much more remains to be understood, and far less is known about other primary conditions of EDS. Several methods have been developed to assess EDS, although each of them has limitations. Treatment is available for the great majority of cases.

Characterization of the spontaneous and gripping-induced immobility episodes on taiep rats.

In 1989, we described a new autosomic-recessive myelin-mutant rat that develops a progressive motor syndrome characterized by tremor, ataxia, immobility episodes (IEs), epilepsy, and paralysis. taiep is the acronym of these symptoms. The rat developed a hypomyelination, followed by demyelination. At an age of 7-8 months, taiep rats developed IEs, characterized electroencephalographically by REM sleep-like cortical activity. In our study, we analyzed the ontogeny of gripping-induced IEs between 5 and 18 months, their dependence to light-dark changes, sexual dimorphism, and susceptibility to mild stress. Our results showed that IEs start at an age of 6.5 months, with a peak frequency between 8.5 and 9.5 months. IEs have two peaks, one in the morning (0800-1000 h) and a second peak in the middle of the night (2300-0100 h). Spontaneous IEs showed an even distribution with a mean of 3 IEs every 2 h. IEs are sexually dimorphic being more common in male rats. The IEs can be induced by gripping the rat by the tail or the thorax, but most of the IEs were produced by gripping the tail. Mild stress produced by i.p. injection of physiological saline significantly decreased IEs. These results suggested that IEs are dependent on several biological variables, which are caused by hypomyelination, followed by demyelization, which causes alterations in the brainstem and hypothalamic mechanisms responsible for the sleep-wake cycle regulation, producing emergence of REM sleep-like behavior during awake periods.

Narcolepsy in Singapore: is it an elusive disease?

INTRODUCTION: The aims of the study were to determine the demographic, clinical, and polysomnographic characteristics of narcolepsy, and to address the difficulties in diagnosing narcolepsy and cataplexy, which is a cardinal symptom. We also ventured to investigate the differences between narcolepsy with and without cataplexy. MATERIALS AND METHODS: Data were collected retrospectively from patients diagnosed with narcolepsy at the Sleep Disorder Unit of Singapore General Hospital over 5 years. Each patient had had a detailed clinical evaluation and overnight polysomnography (PSG) followed by a multiple sleep latency test (MSLT). RESULTS: A total of 28 cases were studied. Males made up 85.7% of the total and females, 14.3%. The mean age was 30.9 years. All had excessive daytime sleepiness. Other manifestations were cataplexy (48.1%), sleep paralysis (51.9%), hypnogogic hallucinations (84%), disturbed night sleep (29.2%), automatisms (17.4%) and catnaps (95.8%). The mean duration of symptoms was 7.24 years. In the MSLT, the mean values for mean sleep latency and number of sleep onset rapid eye movement (REM) periods (SOREMP) were 4.3 minutes and 2.7, respectively. Narcolepsy was associated with obstructive sleep apnoea and periodic limb movement disorder (35.7%). All the variables were compared between those who had narcolepsy with cataplexy and without cataplexy. The duration of presenting complaint, REM latency, respiratory disturbance index, number of SOREMPs and the presence of sleep paralysis were significantly different in the 2 groups. CONCLUSIONS: Narcolepsy predominantly affects young males. Concurrence of other sleep disorders is not uncommon. Some differences are evident between those who have narcolepsy with and without cataplexy.