Nocturnal exposure to a preferred ambient scent does not affect dream emotionality or post-sleep core affect valence in young adults.

Emotions experienced within sleep mentation (dreaming) affect mental functioning in waking life. There have been attempts at enhancing dream emotions using olfactory stimulation. Odors readily acquire affective value, but to profoundly influence emotional processing, they should bear personal significance for the perceiver rather than be generally pleasant. The main objective of the present sleep laboratory study was to examine whether prolonged nocturnal exposure to self-selected, preferred ambient room odor while asleep influences emotional aspects of sleep mentation and valence of post-sleep core affect. We asked twenty healthy participants (12 males, mean age 25 ± 4 years) to pick a commercially available scented room diffuser cartridge that most readily evoked positively valenced mental associations. In weekly intervals, the participants attended three sessions. After the adaptation visit, they were administered the odor exposure and odorless control condition in a balanced order. Participants were awakened five minutes into the first rapid eye movement (REM) stage that took place after 2:30 a.m. and, if they had been dreaming, they were asked to rate their mental sleep experience for pleasantness, emotional charge, and magnitude of positive and negative emotions and also to evaluate their post-sleep core affect valence. With rs < 0.20, no practically or statistically significant differences existed between exposure and control in any outcome measures. We conclude that in young, healthy participants, the practical value of olfactory stimulation with self-selected preferred scents for enhancement of dream emotions and post-sleep core affect valence is very limited.

Parasomnias in Pregnancy.

OBJECTIVES: Pregnancy is often associated with reduced sleep quality and an increase in sleep disorders, such as restless leg syndrome, obstructive sleep apnea, and insomnia. There are few studies investigating the prevalence of parasomnias in pregnancy, although they may be expected to be a significant problem, as disturbed sleep in this time period in addition to these sleep disorders may trigger parasomnia episodes. METHODS: We conducted a survey using an online questionnaire focusing on a comparison of the prevalence of parasomnias in three time periods: 3 months before pregnancy, during pregnancy, and 3 months after delivery. We also inquired about psychiatric and neurological comorbidities, current anxiety and depression symptoms, and pregnancy complications. RESULTS: A total of 325 women (mean age 30.3 ± 5.3 years) participated in the online survey. The overall number of reported parasomnias increased during pregnancy compared to the 3 months before pregnancy (p < 0.001) and decreased after childbirth (p < 0.001). Specifically, we found a significant increase in sleepwalking (p = 0.02) and night terrors (p < 0.001), as well as in vivid dreams (p < 0.001) and nightmares (p < 0.001) during pregnancy. A similar significant increase during pregnancy was reported for head explosion (p < 0.011). In contrast, the number of episodes of sleep paralysis increased after delivery (p = 0.008). At the individual level, an increase in the severity/frequency of individual parasomnia episodes was also observed during pregnancy. Participants whose vivid dreams/nightmares persisted after delivery had higher BDI-II and STAI-T scores. Our data also suggest a significant impact of migraines and other chronic pain, as well as complications during pregnancy, on the presence of parasomnia episodes in our cohort. CONCLUSIONS: We have shown that the prevalence of parasomnias increases during pregnancy and needs to be targeted, especially by non-pharmacological approaches. At the same time, it is necessary to inquire about psychiatric and neurological comorbidities and keep in mind that more sleep disorders may be experienced by mothers who have medical complications during pregnancy.

Self-reported symptoms and objective measures in idiopathic hypersomnia and hypersomnia associated with psychiatric disorders: a prospective cross-sectional study.

STUDY OBJECTIVES: In some patients, it is difficult to correctly nosologically classify daytime sleepiness. Clinical manifestations may be nonspecific; on the basis of objective measures it is possible to determine the current severity of sleepiness, but they do not always allow accurate diagnosis. It is especially difficult to distinguish between idiopathic hypersomnia (IH) and hypersomnia associated with a psychiatric disorder (PSY). METHODS: To find significant differences between the IH and PSY groups, we included 67 patients (IH, n = 15; PSY, n = 52) in the study, focusing on differences in self-reported symptoms, evaluating current depressive symptoms using the Beck Depression Inventory-II score and personality traits measured by the Temperament and Character Inventory. All of the patients underwent polysomnography, the Multiple Sleep Latency Test, and ad libitum sleep monitoring. RESULTS: The patients with IH showed greater difficulty than those in the PSY group with waking up in the morning (P < .001) and complained of memory (P = .04) and attention deficit (P = .006). They also showed higher total sleep time (P < .001) and sleep efficiency (P = .007) and a shorter mean sleep latency on the Multiple Sleep Latency Test (P < .001). Nevertheless, the IH and PSY groups did not differ in Beck Depression Inventory scores or personality characteristics. CONCLUSIONS: IH is a syndrome in which depression/external life stressors and personality characteristics also play a role. Patients with IH may benefit from the cooperation of sleep specialists with psychotherapists/psychiatrists. CITATION: Busková J, Novák T, Miletínová E, et al. Self-reported symptoms and objective measures in idiopathic hypersomnia and hypersomnia associated with psychiatric disorders: a prospective cross-sectional study. J Clin Sleep Med. 2022;18(3):713-720.

Olfaction-Related Factors Affecting Chemosensory Dream Content in a Sleep Laboratory.

Mental activity in sleep often involves visual and auditory content. Chemosensory (olfactory and gustatory) experiences are less common and underexplored. The aim of the study was to identify olfaction-related factors that may affect the occurrence of chemosensory dream content. Specifically, we investigated the effects of all-night exposure to an ambient odour, participants' appraisal of their current olfactory environment, their general propensity to notice odours and act on them (i.e., odour awareness), and their olfactory acuity. Sixty pre-screened healthy young adults underwent olfactory assessment, completed a measure of odour awareness, and spent three nights in weekly intervals in a sleep laboratory. The purpose of the first visit was to adapt to the experimental setting. On the second visit, half of them were exposed to the smell of vanillin or thioglycolic acid and the other half to an odourless control condition. On the third visit, they received control or stimulation in a balanced order. On each visit, data were collected twice: once from the first rapid eye movement (REM) stage that occurred after 3 a.m., and then shortly before getting up, usually from a non-REM stage. Participants were asked to report the presence of sensory dream content and to assess their current olfactory environment. Neither exposure, nor participants' assessments of the ambient odour, or olfactory acuity affected reports of chemosensory dream content but they were more frequent in individuals with greater odour awareness. This finding may have implications for treatment when such experiences become unwanted or bothersome.

Objective rapid eye movement sleep characteristics of recurrent isolated sleep paralysis: a case-control study.

STUDY OBJECTIVES: Recurrent isolated sleep paralysis (RISP) is a rapid eye movement (REM) parasomnia characterized by a dissociative state with characteristics of REM sleep and wakefulness. Pathophysiology has not yet been clarified and very little research has been performed using objective polysomnographic measures with inconsistent results. The main aim of our study was to find whether higher REM sleep fragmentation is consistent with the theory of state dissociation or whether signs of dissociation can be detected by spectral analysis. METHODS: A total of 19 participants in the RISP group and 19 age- and gender-matched participants in the control group underwent two consecutive full-night video-polysomnography recordings with 19-channel electroencephalography. Apart from sleep macrostructure, other REM sleep characteristics such as REM sleep arousal index, percentage of wakefulness and stage shifts within REM sleep period were analyzed, as well as power spectral analysis during REM sleep. RESULTS: No difference was found in the macrostructural parameters of REM sleep (percentage of REM sleep and REM latency). Similarly, no significant difference was detected in REM sleep fragmentation (assessed by REM sleep arousal index, percentage of wakefulness and stage shifts within REM sleep). Power spectral analysis showed higher bifrontal beta activity in the RISP group during REM sleep. CONCLUSIONS: The results showed an underlying persistent trait of higher cortical activity that may predispose patients with sleep paralysis to be more likely to experience recurrent episodes, without any apparent macrostructural features including higher REM sleep fragmentation.

Effects of all-night exposure to ambient odour on dreams and affective state upon waking.

Previous laboratory research has shown that exposure to odours of contrasting pleasantness during sleep differentially affects the emotional tone of dreams. In the present study, we sought to investigate how a generally pleasant (vanillin) and unpleasant (thioglycolic acid [TGA]) smell influenced various dream characteristics, dream emotions, and post-sleep core affect during all-night exposure, controlling for appraisal of the olfactory environment during the assessments and sleep stage from which the participants woke up. We expected that exposure to vanillin would result in more pleasant dreams, more positive and less negative dream emotions, and a more positive post-sleep core affect compared to the control condition, whereas exposure to TGA would have the opposite effect. Sixty healthy volunteers (36 males, mean age 24 ± 4 years) were invited to visit the sleep laboratory three times in weekly intervals. The first visit served to adapt the participants to the laboratory environment. On the second visit, half the participants were exposed to an odour (vanillin or TGA, 1:1) and the other half to the odourless control condition. On the third visit, they received control or exposure in a balanced order. On each visit, the participants woke up twice, first from the rapid eye movement (REM) sleep stage and then in the morning, usually from a non-REM sleep stage. Repeated measures were taken upon each awakening. Dream pleasantness, emotional charge of the dream, positive and negative emotions experienced in the dream, and four dimensions of post-sleep core affect (valence, activation, pleasant activation - unpleasant deactivation, and unpleasant activation - pleasant deactivation) were assessed. We found a small effect of condition (exposure vs. control) in interaction with appraisal of the ambient olfactory environment on dream pleasantness. Specifically, false alarms (i.e., perceiving odour in the absence of the target stimulus) were associated with lower dream pleasantness than correct rejections. Although exposure had a statistically significant positive influence on post-sleep core affect (namely, valence, activation, and pleasant activation - unpleasant deactivation), the size of the effect was small and lacked practical significance. The hypothesised differential effects of vanillin and TGA were only modelled for dream ratings because they decreased the fit of the other models. Neither dream pleasantness nor emotionality differed according to the odour used for stimulation. The results of the present study suggest that all-night exposure to odours is unlikely to produce practically significant positive effects on dreams and post-sleep core affect.

Simultaneous fMRI-EEG-Based Characterisation of NREM Parasomnia Disease: Methods and Limitations.

Functional magnetic resonance imaging (fMRI) techniques and electroencephalography (EEG) were used to investigate sleep with a focus on impaired arousal mechanisms in disorders of arousal (DOAs). With a prevalence of 2-4% in adults, DOAs are significant disorders that are currently gaining attention among physicians. The paper describes a simultaneous EEG and fMRI experiment conducted in adult individuals with DOAs (n=10). Both EEG and fMRI data were validated by reproducing well established EEG and fMRI associations. A method for identification of both brain functional areas and EEG rhythms associated with DOAs in shallow sleep was designed. Significant differences between patients and controls were found in delta, theta, and alpha bands during awakening epochs. General linear models of the blood-oxygen-level-dependent signal have shown the secondary visual cortex and dorsal posterior cingulate cortex to be associated with alpha spectral power fluctuations, and the precuneus with delta spectral power fluctuations, specifically in patients and not in controls. Future EEG-fMRI sleep studies should also consider subject comfort as an important aspect in the experimental design.

3D visual cueing shortens the double support phase of the gait cycle in patients with advanced Parkinson's disease treated with DBS of the STN.

BACKGROUND: Gait disturbances have emerged as some of the main therapeutic concerns in late-stage Parkinson's disease (PD) treated with dopaminergic therapy and deep brain stimulation (DBS). External cues may help to overcome freezing of gait (FOG) and improve some of the gait parameters. AIM: To evaluate the effect of 3D visual cues and STN-DBS on gait in PD group. METHODS: We enrolled 35 PD patients treated with DBS of nucleus subthalamicus (STN-DBS). Twenty-five patients (5 females; mean age 58.9 ±6.3) and 25 sex- and age-matched controls completed the gait examination. The gait in 10 patients deteriorated in OFF state. The severity of PD was evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (HY). The PD group filled the Falls Efficacy Scale-International (FES) and Freezing of Gait Questionnaire (FOGQ). Gait was examined using the GaitRite Analysis System, placed in the middle of the 10m marked path. The PD group was tested without dopaminergic medication with and without visual cueing together with the DBS switched ON and OFF. The setting of DBS was double-blind and performed in random order. RESULTS: The UPDRS was 21.9 ±9.5 in DBS ON state and 41.3 ±13.7 in DBS OFF state. HY was 2.5 ±0.6, FES 12.4 ±4.1 and FOGQ 9.4 ±5.7. In the DBS OFF state, PD group walked more slowly with shorter steps, had greater step length variability and longer duration of the double support phase compared to healthy controls. The walking speed and step length increased in the DBS ON state. The double support phase was reduced with 3D visual cueing and DBS; the combination of both cueing and DBS was even more effective. CONCLUSION: Cueing with 3D visual stimuli shortens the double support phase in PD patients treated with DBS-STN. The DBS is more effective in prolonging step length and increasing gait speed. We conclude that 3D visual cueing can improve walking in patients with DBS.

Associated factors of REM sleep without atonia in younger (≤ 50 years) hospitalized psychiatric patients.

BACKGROUND: Isolated REM sleep without atonia (RSWA) as a main polysomnograhic feature of REM sleep behaviour disorder (RBD) is thought to be a prodromal or subclinical state of the disease. RSWA/RBD occurence in psychiatric population is much more frequent than in general population but its associated factors are still not known. METHODS: We invited 88 psychiatry in-patients to undervent video-polysomnography. The visual scoring was focused on RSWA in submentales and flexores digitales superficiales muscles. This parametr was subsequently correlated mainly with age/gender, their medication and mental status. RESULTS: The RWSA was mostly still in normal range despite the fact, that selected psychiatry patients (≤ 50 years) were taking several classes of psychoactive medication. 3,6% had convincingly RBD, although 35.7% reported rare lifetime occurence of dream-enacting behaviour and 62.8% sporadic nightmares. We found correlation between RSWA and SNRI medication class (p = 0.015), specifically venlafaxine (p = 0.029) as well as quetiapine (p = 0.030). Another significant associated factors were current anxiety (p < 0.001) and depressive symptoms (p = 0.05), but we found no relation between RSWA and given diagnosis. CONLUCIONS: Isolated RSWA in younger psychiatry patients might be a result of multiple factors, including medication and current mental status but these factors are in most cases not sufficient to manifest RBD.

Validation of the REM sleep behavior disorder screening questionnaire in the Czech population.

BACKGROUND: Idiopathic rapid eye movement sleep behavior disorder (iRBD) affects 1-2% of people over 60 years of age and presents a high risk of developing a neurodegenerative disorder from the group of synucleinopathies, such as Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Therefore, screening tools are needed. In 2007, the rapid eye movement sleep behavior disorder screening questionnaire (RBD-SQ) was developed and has been translated into several languages. The aim of study was to assess the validity and reliability of the Czech version of the RBD-SQ in a mixed population of sleep clinic patients, supplemented by healthy volunteers and RBD patients. METHODS: Participants included 81 iRBD patients, 205 patients with other sleep disorders (obstructive sleep apnea, insomnia, restless legs syndrome and periodic limb movement disorder, other parasomnias, or central hypersomnias including narcolepsy) and 20 healthy volunteers. RESULTS: The mean RBD-SQ score in the iRBD patients was 9.4 ± 2.8 points, and in the non-RBD group it was 4.5 ± 3.0 (P < 0.0001). Receiver -operator analysis yielded an area under the curve of 0.864, suggesting good diagnostic performance of the scale. When using a cut-off value for positivity of 5 points, sensitivity was 0.89 and specificity was 0.62. CONCLUSIONS: The Czech version of the RBD-SQ is a sensitive tool for screening for iRBD patients and helps to identify subjects for complete clinical workup.

Locomotion in young rats with induced brain cellular edema - effects of recombinant human erythropoietin.

OBJECTIVES: Effect of recombinant human erythropoietin (rhEPO) on spontaneous motor activity was tested in young rats after intraperitoneal (i.p.) administration of rhEPO, followed by induction of cellular brain edema (CE). Induced changes in the spontaneous horizontal locomotor activity was studied by open field test (OFT). METHODS: CE was induced by water intoxication (WI) using standard method of fractional hyperhydration accompanied with desmopressin administration. Using the accepted method of OFT average time spent in locomotion (s) was determined. 48 young rats at the age of 25, and 35 days were divided into three groups - controls, rats after WI (OFT followed after 44 hours), and rats administered with rhEPO prior to application WI (OFT after 48 hours). RESULTS: In 35-day-old rats rhEPO administration increased the spontaneous locomotor activity, previously decreased by cellular edema. In 25-day-old rats, rhEPO administration prior to the induced CE, decreased spontaneous locomotor activity. CONCLUSION: Presented results demonstrate the neuroprotective capacity of rhEPO, manifested by elimination of the suppressive influence of CE on the locomotion in 35-day-old rats. In 25-day-old rats the neuroprotective effect was not present. These results confirmed that the 10 day interval in the development may represent a different stage of brain maturation in the relation to the neuroprotective effect of rhEPO.

Circadian rhythms of melatonin and peripheral clock gene expression in idiopathic REM sleep behavior disorder.

OBJECTIVE: To evaluate changes in the expression of clock genes and melatonin levels in patients with idiopathic REM sleep behavior disorder (RBD) as a potential early stage of synucleinopathies. METHODS: We assessed the rhythmicity of circadian clock genes using real time-quantitative polymerase chain reaction and 24-h blood melatonin profiles using radio-immunoassay in 10 RBD patients and nine age-matched controls. RESULTS: The RBD patients did not show circadian rhythmicity for clock genes Per2, Bmal1, and Nr1d1 but the rhythmicity of Per 1 remained, and the amplitude of Per3 was diminished. The 24-h melatonin rhythm did not differ between RBD patients and healthy control subjects. Melatonin profile in RBD patients was delayed by 2 h compared to controls, the habitual sleep phases were phase delayed by about 1 h, however no phase shift occurred in any of the clock genes studied. The control group had stable acrophases of melatonin rhythms of approximately 5 h whereas the RBD patients had a more dispersed range over 11 h. CONCLUSIONS: Our results suggest that RBD could be associated with altered expression of clock genes and delayed melatonin secretion. Thus, we argue that circadian system dysregulation could play a role in RBD.

Modafinil Reduces Parasympathetic Activity but Does Not Influence Autonomic Reactivity to Orthostatic Load in Narcolepsy Type 1.

INTRODUCTION: Modafinil may affect autonomic functions in healthy subjects. The aim of the study was to assess the long-term modafinil administration influence on the cardiac autonomic reactivity to orthostatic load in patients with narcolepsy type 1. METHODS: In 15 patients (4 male; 11 female; median age, 47 years; range, 18-70 years) with narcolepsy type 1 treated with modafinil in daily dose of 100 to 300 mg, the short-term spectral analysis of heart rate variability (HRV) in supine-standing-supine test was performed before and after 72 hours of modafinil discontinuation. RESULTS: The sympathovagal reactivity to orthostatic load was not modified by modafinil treatment; nevertheless, the parasympathetic activity expressed by length of R-R interval and high-frequency component of HRV is reduced in supine position in patients taking modafinil. CONCLUSIONS: We conclude that long-term use of modafinil does not influence the cardiac autonomic reactivity to orthostatic load expressed by the HRV changes in supine-standing-supine test in narcolepsy type 1 patients, but the parasympathetic cardiac activity may be reduced in quiet supine position in patients with narcolepsy taking modafinil.