No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The frequency of sleep-talking in the laboratory among chronic sleep-talkers and good dream recallers
Abstract
Chronic sleep talkers utter sleep speech under laboratory conditions at a sufficiently frequent rate as to be capable of providing useful material for study. Fifty-three base line experiments consisting of one or more nights of monitored, otherwise undisturbed sleep were performed on 13 paid subjects offering a history of chronic sleep talking. A total of 206 speeches was recorded. Marked individual differences were observed in total frequency of sleep speech episodes as well as differences in tendencies of association with sleep stages. In general, 20 to 25% of speeches are associated with rapid eye movement period sleep and 75 to 80% are associated with non-rapid eye movement sleep. Additional similar experiments were performed on two larger subject pools: one of chronic sleep talkers and another of good dream recallers with a low arousal threshold. Frequencies of sleep speech and association with specific sleep stages are reported for these conditions as well.
... Tra questi, un'indagine sull'elettrofisiologia delle parasonnie da passaggio di stadio, 19 dal quale emerse un aumento di attività theta precedente l'onset dei tre fenomeni parasonnici indagati, suggerendo che la presenza di attività theta e alpha, accompagnata da una generale attivazione motoria e precedente l'episodio di parlato, predica l'onset di tali parasonnie. 19 In uno studio successivo, Arkin et al. 2 hanno approfondito le caratteristiche di frequenza per stadio di sonno, partendo dalle già disponibili evidenze di una larga diffusione del fenomeno. 20 Le caratteristiche elettromiografiche concomitanti il fenomeno coincidevano in larga parte a quanto riconosciuto come movement arousal nelle norme internazionali di siglatura, 21 lasciando intendere che un certo grado di frammentazione del sonno fosse necessario e permissivo del fenomeno di attivazione vocale. ...
... L'arousal da Sonniloquio non era dunque considerato come indice implicito di passaggio di stadio, ma piuttosto in associazione a questo stesso passaggio, tanto da portare gli autori a definirne una distinzione in base allo stadio a cui si associava ["NREM-associated speeches or utterances, REM period-associated speeches or utterances"]. 2 Nello stesso studio, su un totale di 40 soggetti e 127 notti sperimentali gli autori hanno raccolto 258 attivazioni vocali in totale, 14% delle quali in sonno REM e 86% in sonno NREM, prodotte dall'80% del campione, mentre il rimanente 20% non ha prodotto alcuna attivazione vocale. Al terzo esperimento, effettuato sulla base della frequenza di ricordo onirico, sono stati testati 36 soggetti, 39% dei quali hanno prodotto almeno un'attivazione vocale. ...
... I risultati di Arkin et al. 2 lasciano intendere che il Sonniloquio sia un fenomeno da arousal o passaggio di stadio, così come è stato descritto nelle successive classificazioni internazionali. 1,7,23 La linea di ricerca che risulta maggiormente coerente invece tra i tentativi di definire il Sonniloquio da parte dei primi ricercatori e le ultime ricerche nell'ambito riguardano la definizione della fenomenologia della produzione vocale verbale. ...
INTRODUCTION
Sleep Talking (ST) is defined as the utterance of speech during sleep. The available literature cannot address ST as a REM or NREM parasomnias. Rarely studied as an isolated phenomenon, we currently have no definite evidence of its neural correlates. Recently, psycholinguistic features of verbal production in ST has been investigated, pointing to coherence with formal features of the language in wakefulness. This evidence, within the hypothesis of an involvement of parasomnias in sleep-related cognitive processing, suggests the importance of understanding the neural mechanism underlying ST.
We aimed to investigate EEG correlates predictive of verbal activation (Verbal ST), with a comparison with Non-verbal ST (moaning, laughing, crying, etc…) with the general hypothesis of shared mechanisms with neural correlates of language processing and production.
METHOD
Six highly frequent ST (3M, 3F, age 19-27, mean 23.83±3.60) recruited through an online survey (general health assessment, PSQI for the self-declared quality of sleep, MUPS for self-declared presence and frequency of the phenomenon). Presence and frequency of ST, together with the compliance in maintaining a regular sleep schedule, has been further assessed through one week of home sleep/dream-logs and audio-activated recorder. The suitable participants have been recorded in the laboratory for at least 2-consecutive nights of video-PSG. We pursued the conditions of Verbal and Non-verbal ST, obtaining a total of 21 Verbal ST and 21 Non-verbal ST in Stage 2 NREM. Control comparison has been performed between Vocalizations (N=42 vocal activations, combining Verbal and Non-verbal) and Baseline (N=42 equivalent sleep interval, 2 mins preceding each ST), to assess time-locking and specificity of the observed EEG pattern, in relation with vocal production.
Artifacts were off-line rejected for the 20 seconds EEG preceding each Verbal and Non-verbal ST and Baseline, on a 4-seconds basis. EEG power spectra have been obtained throughout a Fast Fourier Transform (FFT) routine. The power spectra have been then averaged to obtain the canonical sleep EEG bands: delta (0.5-4.5Hz), theta (4.75-7.75Hz), alpha (8-11.75Hz), sigma (12-15.75Hz) and beta (16-24.75Hz), and subsequently log-transformed.
RESULTS
Statistical comparisons (t-Test) show a general decrement in power spectra for Verbal ST vs. Non-verbal ST for the theta and alpha EEG bands. This effect is strongly lateralized to the left hemisphere and specifically localized on centro-parietal-occipitals channels. A single left parietal channel (P7; theta t=-4.48, p=0.0002; alpha t=-3.29, p=0.0037) was significant also after the Bonferroni correction.
T-test comparisons (t=≥2.96; p≤0.0051) for Vocalizations vs. Baseline show a general increment in power spectra for delta on frontal, central and temporal channels, almost on the entire scalp for the alpha band; on Fc2 and C4 for the beta band.
CONCLUSIONS
Our results suggest shared neural mechanisms between Verbal ST and language programming during wakefulness. Specifically, the selective decrement for the theta band on the left parietal sites is coherent with the literature about linguistic planning in wakefulness, suggesting a possible functional overlapping. Moreover, the phenomenon seems time-locked to the interval of sleep preceding ST, as demonstrated throughout a comparison with a preceding sleep interval.
... 8,9 In 468 speech episodes produced by 31 sleep talkers, the median was 13.5 words per speech in NREM stage N1, 7.2 words in NREM stage N2, 6.3 in NREM stage N3, and 7.4 in REM sleep, with a wide variability between subjects. 10 Authors remarked that most sleep-speech is rare (a frequent sleep talker has to be monitored for at least four nights to obtain some verbal material), brief, and consists of a few words rather than extended remarks. 10 However, the syntax, semantics, and content of sleep-speech have not been studied yet, despite the fact that human speech is a complex, high-level function in awake people. ...
... 10 Authors remarked that most sleep-speech is rare (a frequent sleep talker has to be monitored for at least four nights to obtain some verbal material), brief, and consists of a few words rather than extended remarks. 10 However, the syntax, semantics, and content of sleep-speech have not been studied yet, despite the fact that human speech is a complex, high-level function in awake people. We hypothesized that a study of sleep-speech content, using sleep-measurement techniques (video polysomnography) and disorders (adult sleepwalking and RBD) not studied in these ancient works, would shed a new light upon brain functioning during sleep. ...
Objectives:
Speech is a complex function in humans, but the linguistic characteristics of sleep talking are unknown. We analyzed sleep-associated speech in adults, mostly (92%) during parasomnias.
Methods:
The utterances recorded during night-time video-polysomnography were analyzed for number of words, propositions and speech episodes, frequency, gaps and pauses (denoting turn-taking in the conversation), lemmatization, verbosity, negative/imperative/interrogative tone, first/second person, politeness and abuse.
Results:
The 232 subjects (aged 49.5 ± 20 y old; 41% women; 129 with rapid eye movement [REM] sleep behavior disorder and 87 with sleepwalking/sleep terrors, 15 healthy subjects and 1 patient with sleep apnea speaking in non-REM sleep) uttered 882 speech episodes, containing 59% non-verbal utterance (mumbles, shouts, whispers, laughs) and 3349 understandable words. The most frequent word was "No": negations represented 21.4% of clauses (more in non-REM sleep). Interrogations were found in 26% of speech episodes (more in non-REM sleep), and subordinate clauses were found in 12.9% of speech episode. As many as 9.7% of clauses contained profanities (more in non-REM sleep). Verbal abuse lasted longer in REM sleep and was mostly directed towards insulting or condemning someone, whereas swearing predominated in non-REM sleep. Men sleep-talked more than women and used a higher proportion of profanities. Apparent turn-taking in the conversation respected the usual language gaps.
Conclusions:
Sleep talking parallels awake talking for syntax, semantics and turn- taking in conversation, suggesting that the sleeping brain can function at a high level. Language during sleep is mostly a familiar, tensed conversation with inaudible others, suggestive of conflicts.
... Foulkes (1999, p. 10) notes that other sleep behavior such as sleep walking rarely corresponds to dream reports and "there is a somewhat better, but still imperfect, relation between sleep speech and dream speech." Arkin et al. (1966Arkin et al. ( , 1970a, argue that they demonstrate significant overlap between dream reports and sleep talk that occurred during REM sleep, however, this is not clearly the case. Arkin et al. (1966) examined the dream reports and sleep talk of a habitual sleep talker (S) to find correlations between the two. ...
... A famous example is the case of Paul Ingram, a man who began to report bizarre false memories about incest and Satanist cults after hypnotic suggestion (Ofshe, 1992). This gives further reason to be wary of aforementioned experiments of Arkin et al. (1966Arkin et al. ( , 1970a, which involved hypnotism. Heaps and Nash used the Gudjonsson Suggestibility Scale (GSS; Gudjonsson, 1984) to identify interrogative suggestibility (susceptibility to the influence of an authoritative questioning source) and hypnotic suggestibility (susceptibility to influence under hypnosis) in test subjects. ...
I propose a narrative fabrication thesis of dream reports, according to which dream reports are often not accurate representations of experiences that occur during sleep. I begin with an overview of anti-experience theses of Norman Malcolm and Daniel Dennett who reject the received view of dreams, that dreams are experiences we have during sleep which are reported upon waking. Although rejection of the first claim of the received view, that dreams are experiences that occur during sleep, is implausible, I evaluate in more detail the second assumption of the received view, that dream reports are generally accurate. I then propose a ‘narrative fabrication’ view of dreams as an alternative to the received view. Dream reports are often confabulated or fabricated because of poor memory, bizarre dream content and cognitive deficits. It is well documented that narratives can alter between initial REM sleep awakenings and subsequent reports. I argue that we have reason to suspect that initial reports are prone to inaccuracy. Experiments demonstrate that subjects rationalise strange elements in narratives, leaving out supernatural or bizarre components when reporting waking memories of stories. Inaccuracies in dream reports are exacerbated by rapid memory loss and bizarre dream content. Waking memory is a process of reconstruction and blending of elements, but unlike waking memory, we cannot reality-test for dream memories. Dream experiences involve imaginative elements, and dream content cannot be verified with external evidence. Some dreams may involve wake-like higher cognitive functions, such as lucid dreams. Such dreams more likely to elicit accurate reports than cognitively deficient dreams. However, dream reports are generally less accurate than waking reports. I then propose methods which could verify the narrative fabrication, and argue that although the theory cannot be tested with current methods, new techniques and technologies may be able to do so in the future.
... It has been reported that 20% to 25% of sleep talking occurs during rapid eye movement sleep and 75% to 80% occurs during nonrapid eye movement sleep. 30 A high frequency of sleep talking has been observed in patients with RBD, and it is considered a major symptom of RBD. 22 Based on the same prospective cohort-the Kailuan Study-our previous study demonstrated that participants with pRBD had a higher risk of stroke during 3 years of follow-up, relative to those without pRBD. ...
Background
The potential clinical implication of sleep talking in relation to stroke has not been explored to date. This study aimed to prospectively examine the association between sleep talking and the risk of developing stroke in a community‐based cohort.
METHODS AND RESULTS
Included were 8001 participants (mean age, 54 years) of the Kailuan Study, China. Sleep talking was measured by a questionnaire in 2012. Cases of incident stroke were confirmed by review of medical records. Cox proportional hazards models were used to explore the association between sleep talking and stroke, adjusting for several sleep parameters (ie, insomnia, daytime sleepiness, sleep duration, snoring, and use of hypnotics) and other potential confounders. During 8 years of follow‐up, 333 incident stroke cases were identified. Relative to participants without sleep talking at baseline, those with sleep talking had a higher risk of developing stroke (hazard ratio [HR], 1.30 [95% CI, 1.03–1.65]), adjusting for potential confounders. Compared with participants without probable rapid eye movement sleep behavior disorder and sleep talking, those with sleep talking and probable rapid eye movement sleep behavior disorder had a higher risk of stroke (adjusted HR, 1.93 [95% CI, 1.40–2.66]).
Conclusions
The presence of sleep talking was associated with a higher risk of developing stroke. Future studies with cases of clinically confirmed sleep talking and a longer follow‐up would be appropriate to further investigate this association.
... Dream features of parasomnias could be due to the sleep stage from which the dream experience is collected (e.g., REM sleep in RBD, NREM sleep in somnambulism), as dream reports differ between REM-associated (dreamlike: more emotional, vivid, and bizarre mentation) and NREM-associated (thought-like: less emotional intensity and more realistic content) [67][68][69][70]. ST can occur during all sleep phases, although more frequently during NREM sleep periods [34,71,72], especially during N2 [34]. Moreover, the alteration in macrostructure in ST showed a lower amount of REM sleep and a higher amount of NREM sleep [34]. ...
Background: The COVID-19 pandemic increased symptoms of stress and anxiety and induced changes in sleep quality, dream activity, and parasomnia episodes. It has been shown that stressful factors and/or bad sleep habits can affect parasomnia behaviors. However, investigations on how COVID-19 has affected sleep, dreams, and episode frequency in parasomnias are rare. The current study focuses on the impact of the pandemic on a specific parasomnia characterized by speech production (sleep talking, ST). Methods: We selected 27 participants with frequent ST episodes (STs) during the pandemic and compared them with 27 participants with frequent STs from a previous study conducted during a pre-pandemic period. All participants performed home monitoring through sleep logs and recorded their nocturnal STs for one week. Results: We observed a higher frequency of STs in the pandemic group. Moreover, STs were related to the emotional intensity of dreams, independent of the pandemic condition. The pandemic was associated with lower bizarreness of dreams in the pandemic group. There were no differences in sleep variables between the two groups. Conclusion: Overall, these results suggest a stressful effect of COVID-19 on the frequency of STs. Both the pandemic and the frequency of STs affect qualitative characteristics of dreams in this population.
... confusional arousal, night terrors, sleepwalking, nightmares, REM Behavior Disorder [RBD], sexsomnia, and sleep apnea). Although a flourishing literature in the early 1970s investigated ST quantitative electrophysiological features and correspondence with dream contents [1,2,[5][6][7][8][9] only a few recent studies focused on the phenomenon [10][11][12]. Earlier investigations defined ST as an arousal or stage transition phenomenon, considering it frequently occurs within stage transitions and the second part of the night [4,5,13]; ST was reported to be more frequent in NREM sleep [2,14], while language productions were more correct and appropriate in REM sleep [5]. ...
Study Objectives
Sleep talking (ST) has been rarely studied as an isolated phenomenon. Late investigations over the psycholinguistic features of vocal production in ST pointed to coherence with wake language formal features. Therefore, we investigated the EEG correlates of Verbal ST as the overt manifestation of sleep-related language processing, with the hypothesis of shared electrophysiological correlates with wake language production.
Methods
From a sample of 155 Highly frequent STs, we recorded 13 participants (age range 19–30 years, mean age 24.6 ± 3.3; 7F) via vPSG for at least two consecutive nights, and a total of 28 nights. We first investigated the sleep macrostructure of STs compared to 13 age and gender-matched subjects. We then compared the EEG signal before 21 Verbal STs versus 21 Nonverbal STs (moaning, laughing, crying, etc.) in six STs reporting both vocalization types in Stage 2 NREM sleep.
Results
The 2 × 2 mixed analysis of variance Group × Night interaction showed no statistically significant effect for macrostructural variables, but significant main effects for Group with lower REM (%), total sleep time, total bedtime, sleep efficiency index, and greater NREM (%) for STs compared to controls. EEG statistical comparisons (paired-samples Student’s t-test) showed a decrement in power spectra for Verbal STs versus Nonverbal STs within the theta and alpha EEG bands, strongly lateralized to the left hemisphere and localized on centro-parietal-occipitals channels. A single left parietal channel (P7) held significance after Bonferroni correction.
Conclusions
Our results suggest shared neural mechanisms between Verbal ST and language processing during wakefulness and a possible functional overlapping with linguistic planning in wakefulness.
... Further to this, the language content of dreams can at times be verified through sleep talk. Sleep talking is quite common, though not always associated with dreaming and can at times be meaningless, ungrammatical sentences or noises (Arkin et al. 1970). However, it can reflect dream content and also, RBD patients often speak while dreaming (Arnulf 2019;Oudiette et al. 2009). ...
The experience of skilled action occurs in dreams if we take dream reports at face value. However, what these reports indicate requires nuanced analysis. It is uncertain what it means to perform any action in a dream whatsoever. If skilled actions do occur in dreams, this has important implications for both theory of action and theory of dreaming. Here, it is argued that since some dreams generate a convincing, hallucinated world where we have virtual bodies that interact with virtual objects, there is a sense in which we can perform virtual actions. Further, we can also perform skilfully, although not all apparent skilful performance is as it seems. Since the dream world is generated by the dreamer’s own mind, it can be difficult to determine whether the dream world simply allows goals to be achieved without the abilities that would be required in a similar waking scenario. Because of this, individual dream reports alone are insufficient to determine what skills are demonstrated in a particular dream. However, taken with evidence from REM sleep behaviour disorder, incompetent dreams, lucid dreams and motor-skill practise, it is likely that skilled virtual dream performance at times involves both opportunity for virtual behaviour and the display of competence. Evidence from cognitive science suggests that dreamers can also lose competence through forgetting and other cognitive incapacities but, more surprisingly, it is possible to gain abilities in a robust sense, consistent with the idea that some dreams, at least, are virtual realities rather than imagination.
... Somniloquy can arise from all sleep stages [386]. Since there are few systematic PSG studies, no clear profiles have been identified. ...
Parasomnias are defined as “disorders characterized by abnormal behavioral, experiential, or physiological events occurring in association with sleep, specific sleep stages, or sleep–wake transitions” in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The clinical presentation and polysomnographic characteristics, associated factors, pathophysiology, prevalence, and treatment options of the NREM sleep parasomnias (somnambulism and sleep terrors), REM sleep parasomnias (nightmare disorder, recurrent isolated sleep paralysis, and REM sleep behavior disorder), and other parasomnias (sleep enuresis, sleep-related bruxism, sleep-related rhythmic movement disorder, somniloquy, and sleep-related groaning) are reviewed in this chapter. Some of these phenomena remind us that wakefulness and sleep states are not as mutually exclusive as one might believe.
... In such cases, a small part of the brain appears to be awake while the rest of the brain is asleep [2]. This seems to be true for sleep talking as well: producing speech requires the planning and execution of rapid sequences of muscle movements, hence it will most likely occur in nonparalyzed, non-REM sleep stages [3]. This suggests that the speech we say out loud while sleeping ("sleep talk") is not necessarily just the overt counterpart of the things we may silently say in our dreams or nightmares ("dream speech"). ...
In the present article, we will explore what is known about the production of overt speech during the night. We suggest that the study of sleep-talking may be just as interesting and informative as the study of wakeful speech.
... Many common "sleep walking" occurs only in non-REM and is not accompanied by dream recall or other correlated mentation reports. (Spielman & Henrara, 1991;Kales et al., 1966) Sleep talking can occur across all stages of sleep, but significantly, it is REM sleep from which the most elaborate utterances come and also from REM that associated dream recall correlatedwith the utterances is most likely (Arkin, 1991;Arkin et al., 1970aArkin et al., ,1970bRechtshaffen et al., 1962). ...
This article describes similarites of the states of dreaming and MPD, including amnesia and other alterations of memory. It suggests that the dream character, as an hallucinated projection of aspects of the self can be seen as a prototype for the MPD alter. Dreaming may even be a more literal precursor whose physiologic mechanisms for amnesia and the manufacture of alternate identities are recruited in the development of MPD. There are constellations of cognitive and personality processes which operate outside conscious awareness and normally are observ- able primarily in dreams. Extreme early trauma may mutate or overde- velop these dissociated parts and call upon them to "wake up " and function in the external world. We will describe how that this dream model parallels the observed phenomena of MPD more directly than do explanations relying on waking fantasy processes.
... In fact, sleeptalking may be associated with dream mentation arising from mostly REM sleep. 21,22 Language shift may thus occur as a result of oneiric vocalizations. This may be of some importance regarding certain pathologic conditions, such as REM sleep behavior disorder, in which abnormal dreams are reported as usually stressful, frightening and violent. ...
To assess language used during episodes of sleeptalking in bilingual children.
The investigation was accomplished through the parents who, after having received appropriate information, participated by filling out a survey on sleeptalking.
The study was performed in three bilingual schools of the Basque country, a region in northern Spain in which two completely different official languages are spoken.
A total of 1000 parents agreed to participate, and 681 children were studied.
Sleeptalking was reported by 383 (56.3%) of children (mean age 9 years; range: 3-17). Most individuals used their dominant (i.e., native) language during sleep. However, a minority (< 4%) were found to use their non-dominant language persistently during episodes of sleeptalking.
Balanced bilinguals (those who have equal proficiency in both languages) may sleeptalk in either of the two languages. Dominant bilinguals (i.e., having greater proficiency in one language) may preferentially sleeptalk in their dominant language, with immediate past events probably influencing language use in individual subjects on particular nights. Several considerations are postulated as an explanation for the group who systematically exhibited a dominance shift during sleep.
Somniloquie bezeichnet das Sprechen während des Schlafes. Es kann sowohl während des REM-Schlafes als auch während des NREM-Schlafes auftreten. Nicht immer ist das Gesprochene verständlich. Somniloquie tritt im Zusammenhang mit Parasomnien auf, kann aber auch davon unabhängig beobachtet werden. Es kann nach einer Weckreaktion auftreten, kann diese aber auch auslösen.
Parasomnias are abnormal and undesirable behaviors during sleep and are thought to be due to the sleep state instability. Some of them are benign, while some of them point to a possible underlying neurodegenerative process. This article briefly discusses the clinical characteristics, demographics, and pathophysiology of major parasomnias and associated disorders. The classification outlined in this article conforms to the current version of International Classification of Sleep disorders.
Rapid eye movement sleep behavior disorder (RBD) is often defined as dream-enacting behaviors. However, the dreaming features in RBD are less studied than its motor aspects or than RBD as prodromal neurodegeneration. Dream content during RBD is often (40–59%), but not always, recalled afterward. The question whether RBD is not only a motor disorder (loss of muscle atonia) but also a dreaming disorder remains open. On the one hand, RBD-associated dreams differ from “normal” dreaming (in idiopathic RBD as well as in Parkinson’s disease-associated RBD) by a more active/violent content. On the other hand, spontaneous RBD reports may be biased toward remembering scenarios that awakened or injured the sleeping couple. Plus, quiet, ordinary dreaming can also be observed with RBD. When dream content is systematically collected after provoked awakenings in a sleep lab during RBD movements and during quiet REM sleep in RBD patients, its content is not different from that of controls without RBD. RBD behaviors are quite concordant with dream recall, as reported in numerous case reports by history and by direct observation in the sleep laboratory. This concordance has been tested in a single controlled study and debated in the context of the analysis of REM sleep-associated twitches in developing rats. Eventually, RBD can be viewed (via the observation of movements, speech and facial expressions, and their isomorphism with the dream recall) as a (small) window to overtly approach the physiology of dreaming and cognitive processes during REM sleep. It includes how RBD can be used to demonstrate if non-dreamers do actually dream and if eye movements are tightly coordinated with dream images during REM sleep, to test the replay hypothesis for sleep-related verbal and motor memory consolidation and to study the phonetics and semantics of language during sleep.
A wide range of motor-behavioral sleep-related events may simulate RBD episodes, leading to RBD misdiagnosis. RBD mimics include arousalrelated motor manifestations in severe obstructive sleep apnea, disorders of arousal from NREM sleep, sleep-related movement disorders, temporal and frontal nocturnal epileptic seizures, insulinoma-related hypoglycemia and psychogenic disorders. Distinguishing RBD from its mimics may be challenging and even more difficult in cases of comorbidity of RBD with its mimics and in the context of synucleinopathies. In fact, NREM arousal-related episodes clinically indistinguishable from RBD were reported to occur in subjects with PD, Parkinson’s disease dementia, and dementia with Lewy bodies. A correct diagnosis of RBD is of great importance because a misdiagnosis may carry noteworthy clinical, ethical, and even forensic consequences. Several clinical parameters can help distinguish true RBD, but only video-PSG can lead to a conclusive diagnosis. In case of suspicion of epileptic seizures, V-PSG with extended EEG montages is recommended.
Somniloquy is a parasomnia that refers to talking aloud while sleep. This parasomnia usually happens during transitory arousals from NREM sleep. The recording of these parasomnias could be useful to help in the diagnosis of certain psychological pathologies given that they can reflect a state of anxiety or some behaviors which could be identified as psychological diagnosis criteria. In this work-in-progress paper, a mobile platform which only records sleep-talking (excluding other noises or sounds) and analyze them to identify the main emotion in the voice, allowing making a transcription of the conversation, is presented.
Sleep laboratory techniques have become so widely accepted that they are used to define sleep states, rather than merely to describe them, and these techniques are here reviewed. Experiments on animals have shown that sleep is universal, and is essential to life. It is also strongly influenced by biological rhythms, including the circadian rhythm, and there are a number of practical consequences for man. Studies of auditory perception, including verbal stimuli, have demonstrated evaluative psychological processing during sleep. It is still unclear how limited this processing capacity is, compared with waking levels. Learning during sleep has been demonstrated to be impractical – stimuli presented when subjects are truly asleep are never remembered, and sleep learning is only effective in so far as the procedure wakes the sleeper. The effect of sleep on the consolidation of memories of the previous day appears more complex, sleep stage dependent, and remains a possible indication of one of sleep’s functions. Despite having limited perceptual processing capabilities, and no capacity to learn, the sleeper is capable of talking and walking, albeit somewhat ineffectually. More surprising is the accomplishment of being able to wake at a particular time – demanding a precision of time estimation better than that normally achieved when awake.
Articles on sleep have only recently been incuded in compendia concerned primarily with experimental and physiological psychology. This change probably reflects the growing realization that processes regulating various waking behaviors and sleep are linked by common underlying physiological mechanisms. Waking behaviors are modulated by circadian and ultradian rhythms that are tied to sleep, and brain mechanisms concerned with the facilitation and suppression of sleep also control waking behaviors. Neural elements of the brainstem reticular formation and hypothalamus, including biogenic amine systems, appear to have multiple roles in both sleep and waking behavioral functions. Experimental manipulations such as brain lesions or drug treatments that modify sleep, also alter waking behaviors, and vice versa. Interactions between sleep, and feeding, temperature regulation, motor activity, and sensory function are noted throughout our review.
As mentioned in the preceding two chapters, parasomnias may conveniently be divided into two major categories: Primary parasomnias are those due to disorders of sleep per se, and the secondary parasomnias are those that result from dysfunction of other organ systems and that take advantage of the sleeping state to declare themselves. By far, the primary sleep parasomnias are the most common; they are usually the rapid eye movement (REM) sleep behavior disorder if from REM sleep or disorders of arousal if from non-REM sleep. There remains a large group of other parasomnias, many of which are poorly understood, that can cause impressive and distressing activities arising from the sleep period but that are unrelated to disorders of arousal or REM sleep behavior disorder. This last chapter on parasomnias discusses these less-common but fascinating phenomena.
This is a psycholinguistic study of glossolalia produced by four speakers in an experimental setting. Acoustical patterns (signal waveform, fundamental frequency, and amplitude changes) were compared. The frequency of occurrence of vowels and consonants was computed for the glossolalic samples and compared with General American English. The results showed that three of the four speakers had substantially higher vowel-to-consonant ratios than are found in English speech. Phonology, morphology, and syntax of the four glossolalic productions were analyzed. This revealed two distinct forms of glossolalia. One form, which we called "formulaic" tends towards stereotypy and repetitiousness. The second form, which we called "innovative" shows more novelty and unpredictability in the chaining of speech-like elements. These contrastive forms of glossolalia may relate to dimensions of linguistic creativity. Precise correlates with personality patterns, educational backgrounds, psychopathology, and other sociolinguistic variables remain to be employed.
This report is on the prevalence of somniloquy, as revealed by a populational survey of 2,022 schoolchildren aged from 3 to 10 years. Data were collected by means of a multiple choice questionnaire aimed at the investigation of sleep characteristics (sleep characteristics questionnaire-SCQ) and submitted to statistical analysis. The objective was to detect the prevalence of sleep-talk and influence of age, sex and socioeconomic class on its frequency. About half the children of all ages presented somniloquy at least once a year, but less than 10% presented it everyday. No clearmarked correlation with age, sex or socioeconomic class was found. These results do not confirm the generally accepted notion that there is a higher prevalence in the beginning of the first decade of life and suggest also the necessity of further quantitative and objective assessment of this phenomenon.
Sleep laboratory techniques have become so widely accepted that they are used to define sleep states, rather than merely to describe them, and these techniques are here reviewed. Experiments on animals have shown that sleep is universal, and is essential to life. It is also strongly influenced by biological rhythms, including the circadian rhythm, and there are a number of practical consequences for man. Studies of auditory perception, including verbal stimuli, have demonstrated evaluative psychological processing during sleep. It is still unclear how limited this processing capacity is, compared with waking levels. Learning during sleep has been demonstrated to be impractical – stimuli presented when subjects are truly asleep are never remembered, and sleep learning is only effective in so far as the procedure wakes the sleeper. The effect of sleep on the consolidation of memories of the previous day appears more complex, sleep stage dependent, and remains a possible indication of one of sleep's functions. Despite having limited perceptual processing capabilities, and no capacity to learn, the sleeper is capable of talking and walking, albeit somewhat ineffectually. More surprising is the accomplishment of being able to wake at a particular time – demanding a precision of time estimation better than that normally achieved when awake.
The three states of mammalian being, W, REM sleep, and NREM sleep, are not mutually exclusive, and may occur simultaneously, oscillate rapidly, or appear in dissociated or incomplete form to produce primary sleep parasomnias. In addition, dysfunctions of a wide variety of organ systems may take adwide variety of organ systems may take advantage of the sleeping state to declare themselves, resulting in secondary sleep parasomnias. Contrary to popular opinion, the majority of the often bizarre and frightening experiences are not the manifestation of underlying psychological or psychiatric conditions. There is an interesting interaction between sleep-disordered breathing and parasominas. Formal study in an experienced sleep disorders center will usually reveal a diagnosable and treatable condition that explains the spells. Continued study of unusual sleep-related events undoubtedly will reveal more fascinating conditions, expanding our knowledge of sleep physiology, and strengthening the bonds between clinicians and basic-science sleep researchers.
This chapter illustrates that sleep identifies a natural and healthy, temporary, and periodical state of rest, with suspension of the sensorial functions of the organs of sense, as well as those of the voluntary and rational soul. Several motor phenomena occur during sleep, both physiological and pathological. The International Classification of Sleep Disorders, second edition (ICSD-2) lists sleep disorders within eight categories: (1) insomnias, (2) sleep-related breathing disorders, (3) hypersomnias of central origin not due to a circadian rhythm sleep disorder, sleep-related breathing disorder, or other cause of disturbed nocturnal sleep, (4) circadian rhythm sleep disorders, (5) parasomnias, (6) sleep-related movement disorders, (7) isolated symptoms, apparently normal variants and unresolved issues, and (8) other sleep disorders. Some periodic and aperiodic phenomena of sleep are included within different categories of the ICSD-2, without a unifying classification scheme. These are described with their salient characteristics and distinguishing features, ranging from simple movements or symptoms of sleep up to more complex behaviors classified within the parasomnias.
A patient's refusal to participate in recommended treatment is a problem faced in all branches of medicine. However, psychiatry faces special problems because of its authority to impose hospitalization and treatment on unwilling patients. Nowhere is this more poignant than in the treatment of patients exhibiting suicidal behavior where the potential for imminent self-destruction exists. As part of a prospective study to develop utilization review standards for the hospitalization of suicide attempters, cases were identified where there was independent agreement between both the experts' standards and the treating resident psychiatrists that hospitalization was required. Despite this agreement, the patients were not hospitalized because the patients refused. By most criteria, these patients were a high risk group. They had made repeated suicide attempts, used lethal means which eventuated in serious medical consequences, and were still suicidal when referred for treatment. The emergency room psychiatrists reported feeling confused, anxious, and annoyed in dealing with these patients, and the patients signed out against medical advice. A review of these cases indicates that discussions of social control vs. medical responsibility and clear criteria for hospitalization should be incorporated into residency training programs since the emergency room resident faces these tension-producing issues frequently with several different types of patients. Moreover, utilization review criteria may help to set standards which will assist the psychiatrist in making these difficult decisions.
The parasomnias have been identified as a major category of sleep disorders and represent a group of physiologic and behavioral phenomena that occur exclusively during, or are augmented by, the sleeping state. They are commonly encountered in clinical practice and are typically dismissed as "bumps in the night" or attributed to psychiatric disease. Despite their often bizarre nature, most are readily explainable, diagnosable, and treatable. Some have formed the basis for art, literature, and folklore. Pertinent references from a wide variety of disciplines have been collected, and a clinical classification of the parasomnias is proposed to assist in the understanding, diagnosis, and management of these fascinating disorders.
Phasic muscle discharges known currently as "fasciculations" are more frequently encountered in the limb skeletal muscles and predominate in the lower limbs when compared with the upper limbs. Of the lower limbs, the most active during paradoxical sleep (PS) is the anterior tibial muscle. When quantifying phasic discharges of the eyes versus a lower limb muscle during PS, the former are 14 times more frequent than the latter. During PS there is a sporadic and nonsignificant decrease in the tonus of the antigravitational extensor muscles. Isolated phasic discharges in anterior tibial muscles are a stable feature of PS.
The content of 166 sleep speeches uttered by 28 paid chronic sleep talkers in the laboratory was compared to the content of wakeful mentation reports elicited shortly after utterances. Concordance between the two in varying degrees was discernible in 79.2% of rapid eye movement period, 45.8% of stage II and 21.1% of stage III-IV speech report pairs. Concordance tendencies were also studied on several varying experimental conditions.
Anxious arousals originate from all sleep stages and can be classified as: a) stage 4 night terrors; b) rapid eye movement (REM) nightmares; c) stage 2 awakenings; and d) hypnagogic nightmares. We have confirmed Broughton's finding that the night terror, the most severe type of episode, does not occur in sleep but as part of the "arousal response," a complex of autonomic discharge and behavioral symptoms. The full blown night terror is a fight-flight episode combining sleep utterances, sleep walking and hallucinated or delusional mental content associated with terror. There is a significant positive correlation between intensity of night terror and the amount of delta sleep preceding arousal, e.g., stage 4 arousals designated as night terrors are preceded by longer periods of stage 4 than arousals of lesser intensity (p <.05). About two-thirds of both stage 4 and night terrors occurs in the first non-REM (NREM) period. The night terror arises out of physiologically quiescent sleep as indicated by the normal or slightly less them normal cardiorespiratory rates during the first NREM period and absence of skin resistance changes prior to the attack. The night terror is ushered in by sudden loud piercing screams, the subject passing into an aroused state characterized by alpha rhythm, motility, often somnambulism, intense autonomic discharge (precipitous doubling or even tripling of heart rate, great increase in respiratory amplitude, marked decrease in skin resistance), brief duration (1 to 3 minutes), varying degrees of amnesia for the episode, and rapid return to sleep. The night terror is a much more severe phenomenon than the REM nightmare although the latter is far more frequent. The nightmare occurs in REM sleep, is characterized by slight autonomic fluctuations, compared to the night terror, and, in half of instances, a "desomatization" of the anxiety response, that is, absence of its physiological concomitants. The REM state is physiologically activated to begin with, constituting a preparation for fright, possibly a buffer against the extreme terror of the stage 4 variety. The important problem of the triggering mechanisms of the night terror remains unsolved: whether the attack is precipitated by ongoing mental content during delta sleep, or represents a psychosomatic "arousal response" (Broughton). The fact that it can be induced artificially by sounding a buzzer speaks in favor of the latter, the finding of significant mental content in favor of the former. The night terror is not a dream but a symptom emerging from stage 3-4 sleep, associated with a rift in the ego's capacity to control anxiety.
This report is concerned with: the degree of recall of mental content from Stage 4 night terrors; the classification of the types of mental content recalled; the problem of whether the mental content recalled occurred just before, during, or after the explosive onset of the night terror episode, that is, whether it was related to 'prearousal' or 'postarousal' events; and the implications of the above findings for the problem of the nature of the triggering mechanism of the night terror. A mean of 58% recall of mental content from night terrors was found, approximating that reported from elicited nonanxious Stage 3-4 awakenings in normal subjects. As inferred from subjects' reports, content was retrieved from all temporal phases of the night terror, both pre and postarousal, and including in a few instances ongoing mental content during Stage 4 just prior to the sudden eruption of the episode. The fact that the night terror episode does not show a gradual buildup, either psychological or physiological, does not militate against the possible role of ongoing Stage 4 mentation in triggering it. Such mentation may touch upon an intense conflict area, producing a terrifying image or thought, suddenly igniting intense panic. The extensive screaming, cursing and sleeptalking of the night terror may be responses to preceding Stage 4 mental content, as indicated by numerous examples of concordance observed, that is, the mental content recalled closely resembles the sleep utterances that had occurred during the episode. Postarousal content may be elaborated in relation to autonomic response, e.g., fears of dying associated with pounding of the heart. Although the content of night terrors frequently consists of a single scene or thought, there were many reports of traumatic content unique and unusual, quite elaborate and dreamlike, sometimes consisting of one or more scenes in sequence, and very unlikely to have originated in the postarousal period in response to physiological sensation or environmental conditions. In some instances the subject reported that the frightening content caused him to scream and initiated the episode. Although there is a relatively high percentage of recall, memory for the events of the night terror is often fragmentary and there may be marked amnesia. For example, it seems that there is rarely recall of the extensive sleeptalking and screaming that usher in the night terror. Night terrors may be elicited artificially by sounding a buzzer and this constitutes the best evidence that mental activity need not be the only precipitating factor. The hypothesis is advanced that episodes may be triggered either by endogenous ongoing mental activity during Stage 4 sleep or exogenously in the form of loud noises or other external stimulation.
This review conveys the extent of the sleep researcher's interest in, and potential contribution to, the resolution of some of the mysteries still surrounding many clinical disorders. In no area is there a complete understanding of the significance of the sleep disturbances to the overall clinical picture, and undoubtedly this must in part await a more complete understanding of the basic nature and function of sleep itself. The information obtained in the sleep laboratory has already added a new dimension to continuing exploration of many disease processes, and the authors are confident that future work will contribute to the elucidation both of the mechanisms of these disorders and of more rational treatments for them.
The three states of mammalian being--wakefulness, REM sleep, and NREM sleep--are not mutually exclusive and may occur simultaneously, oscillate rapidly, or appear in dissociated or incomplete form to produce primary sleep parasomnias. Dysfunctions of a wide variety of organ systems may take advantage of the sleeping state to declare themselves, resulting in the secondary sleep parasomnias. Contrary to popular opinion, most of these often bizarre and frightening experiences are not the manifestation of underlying psychological or psychiatric conditions. Formal study in an experienced sleep disorders center usually reveals a diagnosable and treatable condition. Various parasomnias may result in injurious or violent behavior. The forensic science implications are beyond the scope of this article but have been reviewed extensively elsewhere. Continued study of unusual sleep-related events undoubtedly will reveal more fascinating conditions, expanding our knowledge of sleep physiology and strengthening the bonds between clinicians and basic science sleep researchers.
Several theories claim that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural function. Phenomenal dream content, however, is not as disorganized as such views imply. The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented. Furthermore, dream content is consistently and powerfully modulated by certain types of waking experiences. On the basis of this evidence, I put forward the hypothesis that the biological function of dreaming is to simulate threatening events, and to rehearse threat perception and threat avoidance. To evaluate this hypothesis, we need to consider the original evolutionary context of dreaming and the possible traces it has left in the dream content of the present human population. In the ancestral environment human life was short and full of threats. Any behavioral advantage in dealing with highly dangerous events would have increased the probability of reproductive success. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again in various combinations would have been valuable for the development and maintenance of threat-avoidance skills. Empirical evidence from normative dream content, children's dreams, recurrent dreams, nightmares, post traumatic dreams, and the dreams of hunter-gatherers indicates that our dream-production mechanisms are in fact specialized in the simulation of threatening events, and thus provides support to the threat simulation hypothesis of the function of dreaming.
Numerous studies have replicated the finding of mentation in both rapid eye movement (REM) and nonrapid eye movement (NREM) sleep. However, two different theoretical models have been proposed to account for this finding: (1) a one-generator model, in which mentation is generated by a single set of processes regardless of physiological differences between REM and NREM sleep; and (2) a two-generator model, in which qualitatively different generators produce cognitive activity in the two states. First, research is reviewed demonstrating conclusively that mentation can occur in NREM sleep; global estimates show an average mentation recall rate of about 50% from NREM sleep--a value that has increased substantially over the years. Second, nine different types of research on REM and NREM cognitive activity are examined for evidence supporting or refuting the two models. The evidence largely, but not completely, favors the two-generator model. Finally, in a preliminary attempt to reconcile the two models, an alternative model is proposed that assumes the existence of covert REM sleep processes during NREM sleep. Such covert activity may be responsible for much of the dreamlike cognitive activity occurring in NREM sleep.
Sleep talking is very common in the general population. Its prevalence remains stable from childhood through adulthood. Sleep talking is often associated with other parasomnias: sleep walking, sleep terrors or REM sleep behavior disorders. It may arise from either REM or non REM sleep, when associated with REM sleep it is more comprehensible and often associated with clear sentences and recall of sleep mentation. Sleep talking is a benign entity and does not require any treatment; however an exceptional organic cause or psychopathology should be suspected if the onset is late (after 25 years); if the mental content is too violent or too emotional.
Sleep is not a static state. During the sleep period, physiologic changes occur throughout the body and brain. This complex, dynamic process can, at times, result in episodes of unusual or undesirable behaviors. These phenomena are called parasomnias. The accurate diagnosis of this group of treatable disorders is important, because they can have a negative impact on sleep, health, and social function. In addition, some of the parasomnias may provide clues to the presence of other underlying pathologic conditions. The parasomnias may be categorized in more than one way, but any attempt to classify such a diverse collection of entities is likely to be somewhat arbitrary. This article discusses the parasomnias according to the classification of the International Classification of Sleep Disorders, with emphasis on those characterized by observable behavior. As the understanding of these disorders (and sleep, in general) continues to deepen, new entities and schemes of classification may emerge.
Non-rapid eye movement parasomnias are unique physical or experiential phenomena that disrupt sleep. Non-rapid eye movement parasomnias are common in children, but they typically outgrow them. Sleep-stage shifts caused by sleep-disordered breathing and associated arousals may be precipitating events for episodes of parasomnia. Seizure disorders should always be considered in the differential diagnosis for the evaluation of parasomnias. Violent or injurious sleepwalking should be rapidly evaluated and treated.
Parasomnias are unpleasant or undesirable behavioral or experiential phenomena that occur during sleep. Once believed unitary phenomena related to psychiatric disorders, it is now clear that parasomnias result from several different phenomena and usually are not related to psychiatric conditions. Parasomnias are categorized as primary (disorders of the sleep states) and secondary (disorders of other organ systems that manifest themselves during sleep). Primary sleep parasomnias can be classified according to the sleep state of origin: rapid eye movement sleep, non-rapid eye movement sleep, and miscellaneous (those not respecting sleep state). Secondary sleep parasomnias are classified by the organ system involved.
Overnight EEG's were recorded on 12 subjects from 12–53 years of age. Records obtained before and after nocturnal behavior such as sleep-talking, bed-wetting, and tooth-grinding were analyzed in terms of frequency. (1) Immediately before sleep-talking occurred during activated sleep the theta wave component of desynchronization in relation to activated sleep decreased momentarily. (2) Adult enuresis occurred during the synchronization phase of activated sleep (episodical appearance of alpha waves). (3) Tooth-grinding was observed most frequently during the spindle phase and occasionally during activated sleep. In the spindle stage components of theta, alpha, and beta waves were augmented immediately before the tooth-grinding occurred and in activated sleep the theta wave component was suppressed. (4) A comparison of EEG before and after parasomnia behavior revealed a theta wave component in the cortical EEG. The theta wave component probably represents a cortical invasion by the hippocampal theta wave.
In recent years, the work of Aserinsky, Dement, Kleitman, and others1-5 has stimulated research on the relationship of electroencephalographic (EEG) and eye-movement patterns to dreaming. This type of research usually involves continuous monitoring of the EEG's of sleeping subjects. In those laboratories where the use of an intercom system has permitted simultaneous sound monitoring of subjects' sleeping rooms, investigators have had the opportunity to hear subjects talking in their sleep. This paper reports our observations of sleep talking and its relationship to EEG patterns, dreaming, and other variables.
Since our findings will be discussed in the context of the recent EEG-dream research, a brief introduction to this area is indicated. In one of their reports, Dement and Kleitman defined 4 EEG stages of sleep: Stage 1—low voltage, random activity; Stage 2—spindling and K complexes against a low-voltage background; Stage 3—spindling and K complexes against a