Detecting Lucid Dreams by Electroencephalography and Eyebrow Movements

Objective  When metacognition arises during rapid eye movement (REM) sleep, people experience lucid dreaming (LD). Studies on this phenomenon face different obstacles. For example, its standard verification protocol requires at least three types of sensors. We hypothesized that preagreed frontalis movements (PAFMs), as a sign of lucidity, could be seen on electroencephalography (EEG) during REM sleep. In this case, only one EEG sensor would be needed to verify LD. Method  Under laboratory observation, five volunteers were instructed to induce LD, during which they needed to use the standard verification protocol with pre-agreed eye movements (PAEMs) and then immediately raise their eyebrows three times as a PAFM. Results  All participants were able to send signals from a total of eight LDs using one or both methods. Preagreed frontalis movements and PAEMs were equally distinctive on most EEGs, but PAFM quality was strongly dependent on the accuracy of the method. Preagreed frontalis movements exhibited two types of EEG patterns and led to immediate awakening when LD was not stable. Discussion  Though the outcomes show that PAFMs can be used to verify LD, this method was less consistent and apparent than PAEMs. Furthermore, accurate instructions are needed before using PAFMs. When polysomnography is unavailable, PAFMs can be applied, as it requires only one EEG sensor to detect REM sleep and consciousness simultaneously.

Severity of REM sleep without atonia correlates with measures of cognitive impairment and depressive symptoms in REM sleep behaviour disorder

This study aimed to correlate REM sleep without atonia (RSWA) and neuropsychological data in patients with idiopathic/isolated REM sleep behaviour disorder (iRBD) and those with RBD associated with Parkinson's disease (PDRBD), in order to assess whether higher degrees of RSWA are related to poorer cognitive performance. A total of 142 subjects were enrolled: 48 with iRBD, 55 with PDRBD, and 39 PD without RBD (PDnoRBD). All participants underwent video-polysomnographic recording, clinical and neuropsychological assessment. RSWA was quantified according to two manual scoring methods (Montréal, SINBAR) and one automated (REM atonia index, RAI). Mild cognitive impairment (MCI) was diagnosed according to diagnostic criteria for MCI in Parkinson's disease. The relationship between neuropsychological scores and RSWA metrics was explored by multiple linear regression analysis and logistic regression models. Patients with iRBD showed significantly lower visuospatial functions and working memory, compared with the others. More severe RSWA was associated with a higher risk of reduced visuospatial abilities (OR 0.15), working memory (OR 2.48), attention (OR 2.53), and semantic fluency (OR 0.15) in the iRBD. In the whole group, a greater RSWA was associated with an increased risk for depressive symptoms (OR 3.6). A total of 57(40%) MCI subjects were found (17 iRBD, 26 PDRBD, and 14 PDnoRBD). Preserved REM-atonia was associated with a reduced odds of multi-domain MCI in the whole study population (OR 0.54). In conclusion, a greater severity of RSWA was associated with an increased risk for poor cognitive performance and depressive mood in patients with RBD. Moreover, higher RAI was associated with a lower risk of multi-domain MCI.

Effects of bupropion and SSRI antidepressants on leg movement activity and chin muscle tone during sleep in adolescents

STUDY OBJECTIVES

To evaluate the effects of bupropion on periodic limb movements during sleep (PLMS) and chin electromyography tone in children taking it for their mood disorder, compared to the effects of selective serotonin reuptake inhibitors (SSRIs) and of bupropion combined with SSRIs.

METHODS

Six adolescents (aged 16.0 ± 0.63 years) taking bupropion alone and 6 adolescents (aged 15.9 ± 1.36 years) taking bupropion in combination with an SSRI antidepressant were recruited, along with 10 adolescents (aged 16.2 ± 0.2 years) taking different SSRIs, and they were also enrolled together with 17 age- and sex-matched control patients (aged 15.5 ± 1.26 years). Polysomnographic studies were obtained, and participants' leg movement activity during sleep and muscle tone were assessed quantitatively (atonia index) during all sleep stages.

RESULTS

Participants taking SSRIs showed PLMS indices significantly higher than those of control patients, whereas adolescents taking bupropion showed only slightly increased indexes of nonperiodic leg movements during sleep. No differences in PLMS were observed between adolescents taking bupropion alone or in association with SSRIs. The atonia index showed, within each sleep stage, the lowest values in the 2 groups taking SSRIs and the highest in the control patients; adolescents taking bupropion alone tended to show values slightly smaller than those of the control patients.

CONCLUSIONS

We found that similar to adults, in adolescents SSRIs but not bupropion are associated with increased PLMS. Bupropion also seems to counteract the SSRI-induced increase of PLMS, when administered in combination; thus, the dopaminergic effect of bupropion seems to outmatch the antidopaminergic action of SSRIs. Conversely, bupropion does not counteract the effects of SSRIs on chin electromyography tone.

CITATION

DelRosso LM, Mogavero MP, Fickensher A, Bruni O, Schenck CH, Ferri R. Effects of bupropion and SSRI antidepressants on leg movement activity and chin muscle tone during sleep in adolescents. J Clin Sleep Med. 2023;19(1):151-161.

Trazodone affects periodic leg movements and chin muscle tone during sleep less than selective serotonin reuptake inhibitor antidepressants in children

STUDY OBJECTIVES

To test the hypothesis that children taking trazodone have less leg movements during sleep (LMS) and higher rapid eye movement (REM) sleep atonia than children taking selective serotonin reuptake inhibitors (SSRIs) but more than normal controls.

METHODS

Fifteen children (9 girls and 6 boys, mean age 11.7 years, standard deviation [SD] 3.42) taking trazodone (median dosage 50 mg/d, range 25-200 mg) for insomnia and 19 children (11 girls and 8 boys, mean age 13.7 years, SD 3.07) taking SSRIs for depression, anxiety, or both were consecutively recruited, as well as an age- and sex-matched group of 25 control children (17 girls and 8 boys, mean age 13.7 years, SD 3.11). LMS were scored and a series of parameters was calculated, along with the analysis of their time structure. The Atonia Index was then computed for each non-REM sleep stage and for REM sleep.

RESULTS

Children taking trazodone exhibited slightly higher leg movement indices than controls but lower than those found in children taking SSRIs and their time structure was different. Chin electromyogram atonia in all sleep stages was not significantly altered in children taking trazodone but was decreased in children taking SSRIs, especially during non-REM sleep.

CONCLUSIONS

In children, SSRIs but not trazodone are associated with a significantly increased number of LMS, including periodic LMS, and increased chin tone in all sleep stages. The assessment of periodic limb movement disorder and REM sleep without atonia might not be accurate when children are taking SSRIs because of their significant impact.

CITATION

DelRosso LM, Mogavero MP, Bruni O, Schenck CH, Fickenscher A, Ferri R. Trazodone affects periodic leg movements and chin muscle tone during sleep less than selective serotonin reuptake inhibitor antidepressants in children. J Clin Sleep Med. 2022;18(12):2829-2836.

Comparison of rapid eye movement without atonia quantification methods to diagnose rapid eye movement sleep behavior disorder: a systematic review

Study Objectives

Rapid eye movement (REM) sleep without atonia (RWA) is essential for diagnosing REM sleep behavior disorder (RBD). Manual and automatic quantifications of RWA that use different criteria have been validated. This study compared the RWA quantification methods for diagnosing RBD.

Methods

The PubMed, EMBASE, Web of Science, and Cochrane Library databases were systemically searched for studies published from inception to December 2021. The inclusion criteria were cohort, cross-sectional, and case-control studies assessing the sensitivity and specificity of RWA quantification methods. Pooled estimates of the sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curve (AUC) were determined. Risk of bias and certainty of evidence was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool and the Grading of Recommendations, Assessment, Development, and Evaluations framework, respectively.

Results

Fourteen articles including 402 patients with RBD met the inclusion criteria. Manual methods evaluating any chin and phasic flexor digitorum superficialis (FDS) activity had the highest DOR (138.8, 95% CI = 21.8% to 881.7%) and AUC (0.9686). The automatic REM atonia index (RAI) showed similar or higher sensitivity (89.1%, 95% CI = 84.6% to 92.7%) but a lower specificity (73.5%), DOR (43.1), and AUC (0.9369) than the manual techniques.

Conclusions

In this meta-analysis, manual RWA quantification that employed chin or phasic FDS activity had the best RBD diagnostic performance. The automatic RAI method may be useful for screening patients with RBD. The results should be interpreted carefully because of the high risk of bias in patient selection and significant heterogeneity among the studies.

PROSPERO Registration number

CRD42021276445.

Neurophysiological Aspects of REM Sleep Behavior Disorder (RBD): A Narrative Review

REM sleep without atonia (RSWA) is the polysomnographic (PSG) hallmark of rapid eye movement (REM) sleep behavior disorder (RBD), a feature essential for the diagnosis of this condition. Several additional neurophysiological aspects of this complex disorder have also recently been investigated in depth, which constitute the focus of this narrative review, together with RSWA. First, we describe the complex neural network underlying REM sleep and its muscle atonia, focusing on the disordered mechanisms leading to RSWA. RSWA is then described in terms of its polysomnographic features, and the methods (visual and automatic) currently available for its scoring and quantification are exposed and discussed. Subsequently, more recent and advanced neurophysiological features of RBD are described, such as electroencephalography during wakefulness and sleep, transcranial magnetic stimulation, and vestibular evoked myogenic potentials. The role of the assessment of neurophysiological features in the study of RBD is then carefully discussed, highlighting their usefulness and sensitivity in detecting neurodegeneration in the early or prodromal stages of RBD, as well as their relationship with other proposed biomarkers for the diagnosis, prognosis, and monitoring of this condition. Finally, a future research agenda is proposed to help clarify the many still unclear aspects of RBD.

Neurophysiological Aspects of REM Sleep Behavior Disorder (RBD): A Narrative Review

REM sleep without atonia (RSWA) is the polysomnographic (PSG) hallmark of rapid eye movement (REM) sleep behavior disorder (RBD), a feature essential for the diagnosis of this condition. Several additional neurophysiological aspects of this complex disorder have also recently been investigated in depth, which constitute the focus of this narrative review, together with RSWA. First, we describe the complex neural network underlying REM sleep and its muscle atonia, focusing on the disordered mechanisms leading to RSWA. RSWA is then described in terms of its polysomnographic features, and the methods (visual and automatic) currently available for its scoring and quantification are exposed and discussed. Subsequently, more recent and advanced neurophysiological features of RBD are described, such as electroencephalography during wakefulness and sleep, transcranial magnetic stimulation, and vestibular evoked myogenic potentials. The role of the assessment of neurophysiological features in the study of RBD is then carefully discussed, highlighting their usefulness and sensitivity in detecting neurodegeneration in the early or prodromal stages of RBD, as well as their relationship with other proposed biomarkers for the diagnosis, prognosis, and monitoring of this condition. Finally, a future research agenda is proposed to help clarify the many still unclear aspects of RBD.

Detecting lucid dreams only by submentalis electromyography

Lucid dreams (LDs) occur when people become aware that they are dreaming. This phenomenon has a wide range of possible applications from the perspectives of psychology, training physical movements, and controlling computers while asleep, among others. However, research on LDs might lack efficiency because the standard LD verification protocol uses polysomnography (PSG), which requires an expensive apparatus and skilled staff. The standard protocol also may reduce LD-induction efficiency. The current study examines whether humans can send phasic signals through submentalis electromyography (EMG) during muscle atonia via pre-agreed chin movements (PACM). This ability would manifest both REM sleep and consciousness, which are the main features of LDs. In laboratory conditions volunteers were instructed to open their jaws three times while in an LD right after the standard verification protocol to achieve the research goal. Results: 4 of 5 volunteers proved to be in an LD using the standard protocol, and then all of them made PACM. The outcomes show that dream signals cannot be blocked in the submentalis area during muscle atonia. Also, this finding can be considered to develop a simplified, reliable LD protocol that needs only one EMG sensor. The cost of this protocol could be only a small percentage of the current protocol, making it more convenient for researchers and volunteers. It can also be used remotely by inbuilt in wearable gadgets. Considering PACM could speed up LD research and provide many discoveries and new opportunities. Also, it can be used in sleep paralysis studies.

Sleep stage-dependent changes in tonic masseter and cortical activities in young subjects with primary sleep bruxism

STUDY OBJECTIVES

The present study investigated the hypothesis that subjects with primary sleep bruxism (SB) exhibit masseter and cortical hyperactivities during quiet sleep periods that are associated with a high frequency of rhythmic masticatory muscle activity (RMMA).

METHODS

Fifteen SB and ten control participants underwent polysomnographic recordings. The frequencies of oromotor events and arousals and the percentage of arousals with oromotor events were assessed. Masseter muscle tone during sleep was quantified using a cluster analysis. Electroencephalography power and heart rate variability were quantified and then compared between the two groups and among sleep stages.

RESULTS

The frequency of RMMA and percentage of arousals with RMMA were significantly higher in SB subjects than in controls in all stages, while these variables for non-rhythmic oromotor events did not significantly differ between the groups. In SB subjects, the frequency of RMMA was the highest in stage N1 and the lowest in stages N3 and R, while the percentage of arousals with RMMA was higher in stage N3 than stages N1 and R. The cluster analysis classified masseter activity during sleep into two clusters for masseter tone and contractions. Masseter muscle tone showed typical stage-dependent changes in both groups, but did not significantly differ between the groups. Furthermore, no significant differences were observed in electroencephalography power or heart rate variability between the groups.

CONCLUSION

Young SB subjects exhibited sleep stage-dependent increases in the responsiveness of RMMA to transient arousals, but did not show masseter or cortical hyperactivity during sleep.

Increased Chin Muscle Tone during All Sleep Stages in Children Taking SSRI Antidepressants and in Children with Narcolepsy Type 1

STUDY OBJECTIVES

To assess if selective serotonin reuptake inhibitor (SSRI) antidepressants are able to modify the chin EMG tone during sleep also in children.

METHODS

Twenty-three children and adolescents (12 girls, mean age 14.1 years, SD 2.94) under therapy with antidepressant for their mood disorder were consecutively recruited and had a PSG recording. Twenty-one were taking were taking SSRI and treatment duration was 2-12 months. An age- and sex matched group of 33 control children (17 girls, mean age 14.2 years, SD 2.83) and 24 children with narcolepsy type 1 (12 girls, mean age 13.7 years, SD 2.80) were also included. The Atonia Index was then computed for each NREM sleep stage and for REM sleep, also all EMG activations were counted.

RESULTS

Atonia Index in all sleep stages was found to be significantly reduced in children with narcolepsy followed by the group taking SSRI antidepressants and the number of EMG activations was also increased in both groups. Fluoxetine, in particular, was found to be significantly associated with reduced Atonia index during NREM sleep stages N1, N2, and N3, and with increased number of EMG activations/hour during sleep stage N3.

CONCLUSIONS

Similarly to adults, SSRI antidepressants are able to modify the chin EMG tone also in children during REM sleep, as well as during NREM sleep stages. Different pharmacological properties of the different SSRI might explain the differential effect on chin tone during sleep found in this study.

Systematic video-analysis of motor events during REM sleep in idiopathic REM sleep behavior disorder, follow-up and DAT-SPECT

Abnormal motor manifestations in REM sleep are the most visible feature of idiopathic REM sleep behavior disorder (iRBD), which precedes the overt alpha-synucleinopathy. The aim of this study was to perform a systematic visual analysis of the motor events (ME) captured during video-polysomnography, and clarify their relation to the disease severity. Thirty-four iRBD patients (5 women, 29 men; age 67.7 ± 7.2) with a mean follow-up duration 2.9 ± 1.1 years. and 33 controls (10 women, 23 men; age 61.5 ± 8.2) were examined. The ME captured during REM sleep were classified into four categories, previously defined by Frauscher et al. according to clinical severity: minor/simple jerks, major, complex and violent. An average frequency of 110.8 ± 75.2 ME per hour were identified in iRBD, 7.5 ± 11.6 in the controls (p < 0.001). Of these ME, 68.4% were classified as minor/simple jerks, 9.3% as major, 21.7% as complex and 0.7% as violent. The ME frequency was negatively associated with tracer binding on dopamine transporter single-photon emission computed tomography (DAT-SPECT); the association was stronger for caudate nucleus compared to putamen. During follow-up seven patients (24.1%) phenoconverted, yielding a yearly phenoconversion rate 8.3%. Violent ME were associated with increased hazard ratio for phenoconversion in frequency (p = 0.012) and total duration (p = 0.007). Patients with higher amounts of violent ME had a greater risk of phenoconversion; therefore, their role as a predictor should be considered. Additionally, ME were associated with nigrostriatal degeneration, according to DAT-SPECT. These findings indicate that the degree of the clinical severity of motor manifestations in iRBD reflects the severity of the disease.

Normative and isolated rapid eye movement sleep without atonia in adults without REM sleep behavior disorder

STUDY OBJECTIVES

Values for normative REM sleep without atonia (RSWA) remain unclear. Older age and male sex are associated with greater RSWA, and isolated elevated RSWA has been reported. We aimed to describe normative RSWA and characterize isolated RSWA frequency in adults without REM sleep behavior disorder (RBD).

METHODS

We visually quantified phasic, "any," and tonic RSWA in the submentalis (SM) and anterior tibialis (AT) muscles, and the automated Ferri REM Atonia Index during polysomnography in adults without RBD aged 21-88. We calculated RSWA percentiles across age and sex deciles and compared RSWA in older (≥ 65) versus younger (<65) men and women. Isolated RSWA (exceeding diagnostic RBD cutoffs, or >95th percentile) frequency was also determined.

RESULTS

Overall, 95th percentile RSWA percentages were SM phasic, any, tonic = 8.6%, 9.1%, 0.99%; AT phasic and "any" = 17.0%; combined SM/AT phasic, "any" = 22.3%, 25.5%; and RAI = 0.85. Most phasic RSWA burst durations were ≤1.0 s (85th percentiles: SM = 1.07, AT = 0.86 seconds). Older men had significantly higher AT RSWA than older women and younger patients (all p < 0.04). Twenty-nine (25%, 18 men) had RSWA exceeding the cohort 95th percentile, while 17 (14%, 12 men) fulfilled diagnostic cutoffs for phasic or automated RBD RSWA thresholds.

CONCLUSIONS

RSWA levels are highest in older men, mirroring the demographic characteristics of RBD, suggesting that older men frequently have altered REM sleep atonia control. These data establish normative adult RSWA values and thresholds for determination of isolated RSWA elevation, potentially aiding RBD diagnosis and discussions concerning incidental RSWA in clinical sleep medicine practice.

Comparison of EMG power during sleep from the submental and frontalis muscles

OBJECTIVE

Submentalis electromyography (sEMG) and frontalis electromyography (fEMG) muscle activities have been used to assist in the staging of sleep and detection of disruptions in sleep. This study was designed to assess the concordance between sEMG and fEMG power, by and across sleep stages.

METHODS

Forty-three records with simultaneous acquisition of differential signals from the submental and frontalis muscles were evaluated. Sleep stages were assigned using the poly-somnography signals based on majority agreement of five technicians. The sEMG and fEMG signals were identically filtered and aligned prior to cross-correlation analysis.

RESULTS

A strong concordance between sEMG and fEMG power was observed, with 95% of the records exhibiting at least moderate agreement. During rapid eye movement (REM) sleep, sEMG power was significantly less than fEMG power, but exhibited four times greater across-subject variability. fEMG power during wake and non-REM (NREM) sleep was greater than sEMG power, but with 50% less variability. Differences in wake and N1 mean power and between the other sleep stages were more distinct in the fEMG recordings. Relative changes in sEMG and fEMG power across wake, NREM, and REM stages were essentially identical with median by-subject cross correlations of 0.98 and interquartile ranges of 0.97 and 0.99, respectively.

CONCLUSION

The fEMG and sEMG power values were similar during wakefulness and sleep; however, the frontalis exhibits substantially less between-subject variability. This study established face validity for the use of fEMG in the detection of wake and stages of sleep, and for future applications toward assessment of quantitative REM sleep muscle activity in REM sleep behavior disorder.

Nocturnal REM Sleep Without Atonia Is a Diagnostic Biomarker of Pediatric Narcolepsy

STUDY OBJECTIVES

Compare nocturnal REM sleep without atonia (nRWA) and REM sleep behavior disorder (RBD) between pediatric patients with and without narcolepsy and determine if the nRWA index is a valid diagnostic biomarker for narcolepsy.

METHODS

Retrospective cohort study of children ages 6 to 18 years who completed a nocturnal polysomnogram (PSG) and Multiple Sleep Latency Test (MSLT). Our study sample included 11 patients with narcolepsy type 1 (NT1), 6 with narcolepsy type 2 (NT2), 12 with idiopathic hypersomnia (IH), and 11 with subjective hypersomnia (sHS). We compared group nRWA indices (epochs of RWA/total stage R sleep epochs) from the nocturnal PSGs and analyzed nRWA index receiver operating curve (ROC) statistics for narcolepsy diagnosis.

RESULTS

The median nRWA index of patients with NT1 was 15 to 30 times higher compared to sHS and IH (Ps < .005) but similar to that of the NT2 group (P = .46). RBD was present in 25% of patients with narcolepsy (NT1 and NT2). In comparing those with and without narcolepsy, the nRWA index area under the curve was 0.87 (0.6), 95% confidence interval (CI) = 0.75 to 0.99, P < .001. The threshold of having ≥ 1% of stage R sleep epochs with nRWA yielded a sensitivity of 88.2%, 95% CI = 63.6-98.5 and specificity of 60.9%, 95% CI = 38.5 to 80.3 for diagnosis of narcolepsy. In contrast, a threshold of ≥ 8% yielded a specificity of 95.7%, 95% CI = 78.1 to 99.9 and sensitivity of 52.9%, 95% CI = 27.8 to 77.

CONCLUSIONS

The nRWA index is a very good diagnostic biomarker of pediatric narcolepsy. Depending on the clinical cutoffs utilized, this biomarker can identify more children/adolescents with narcolepsy using just the PSG or reduce false-positive diagnostic results.

The spectrum of REM sleep-related episodes in children with type 1 narcolepsy

Type 1 narcolepsy is a central hypersomnia due to the loss of hypocretin-producing neurons and characterized by cataplexy, excessive daytime sleepiness, sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. In children, close to the disease onset, type 1 narcolepsy has peculiar clinical features with severe cataplexy and a complex admixture of movement disorders occurring while awake. Motor dyscontrol during sleep has never been systematically investigated. Suspecting that abnormal motor control might affect also sleep, we systematically analysed motor events recorded by means of video polysomnography in 40 children with type 1 narcolepsy (20 females; mean age 11.8 ± 2.6 years) and compared these data with those recorded in 22 age- and sex-matched healthy controls. Motor events were classified as elementary movements, if brief and non-purposeful and complex behaviours, if simulating purposeful behaviours. Complex behaviours occurring during REM sleep were further classified as 'classically-defined' and 'pantomime-like' REM sleep behaviour disorder episodes, based on their duration and on their pattern (i.e. brief and vivid-energetic in the first case, longer and with subcontinuous gesturing mimicking daily life activity in the second case). Elementary movements emerging either from non-REM or REM sleep were present in both groups, even if those emerging from REM sleep were more numerous in the group of patients. Conversely, complex behaviours could be detected only in children with type 1 narcolepsy and were observed in 13 patients, with six having 'classically-defined' REM sleep behaviour disorder episodes and seven having 'pantomime-like' REM sleep behaviour disorder episodes. Complex behaviours during REM sleep tended to recur in a stereotyped fashion for several times during the night, up to be almost continuous. Patients displaying a more severe motor dyscontrol during REM sleep had also more severe motor disorder during daytime (i.e. status cataplecticus) and more complaints of disrupted nocturnal sleep and of excessive daytime sleepiness. The neurophysiological hallmark of this severe motor dyscontrol during REM sleep was a decreased atonia index. The present study reports for the first time the occurrence of a severe and peculiar motor disorder during REM sleep in paediatric type 1 narcolepsy and confirms the presence of a severe motor dyscontrol in these patients, emerging not only from wakefulness (i.e. status cataplecticus), but also from sleep (i.e. complex behaviours during REM sleep). This is probably related to the acute imbalance of the hypocretinergic system, which physiologically acts by promoting movements during wakefulness and suppressing them during sleep.

Sodium oxybate treatment in narcolepsy and its effect on muscle tone

AIMS

To estimate the effect of the compound sodium oxybate (SO) on chin muscle tone in sleep, a re-analysis of the results of the international multicenter study SXB-15 was performed, applying a validated semi-automatic analysis of muscle tone. This analysis distinguishes short (<0.5 s) and long (>0.5 s) muscle activity indices per hour (SMI, LMI) in 116 patients with narcolepsy-cataplexy. While stable stimulant medication was permitted, tricyclics and SSRIs were withdrawn. Polysomnographies were performed at baseline (V5), four weeks after titration of SO to 4.5 g, 6 g, or 9 g or placebo (V6) and after another four weeks on stable SO dose (V7).

RESULTS

SMI and LMI decreased significantly during light sleep. LMI remained stable in all SO groups during slow wave sleep (SWS), but decreased significantly during REM sleep. SMI decreased non-significantly, but consistently during SWS and REM in the 9 g group only. A subgroup analysis of patients who stayed on stimulants showed that they had higher SMIs and LMIs in all groups. Patients who had been treated with anticataplectic medication prior to study inclusion had lower LMIs in the 9 g group during REM sleep in all visits.

CONCLUSION

SO has a differential effect on muscle tone that is dose and sleep stage dependent. Low dosages increase short muscle activity, possibly enabling the occurrence of parasomnias. High doses are especially efficacious in REM sleep, suggesting that SO could be used to treat REM sleep behavior disorder. Comedication with stimulants and prior medication with anticataplectic medication exerts an influence on muscle tone.

Rapid Eye Movement Sleep Abnormalities in Children with Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS)

STUDY OBJECTIVES

Polysomnographic investigation of sleep architecture in children presenting with pediatric acute-onset neuropsychiatric syndrome (PANS).

METHODS

Fifteen consecutive subjects meeting criteria for PANS (mean age = 7.2 y; range 3-10 y) underwent single-night full polysomnography (PSG) read by a pediatric neurologist.

RESULTS

Thirteen of 15 subjects (87%) had abnormalities detected with PSG. Twelve of 15 had evidence of rapid eye movement (REM) sleep motor disinhibition, as characterized by excessive movement, laughing, hand stereotypies, moaning, or the continuation of periodic limb movements during sleep (PLMS) into REM sleep.

CONCLUSIONS

This study shows various forms of REM sleep motor disinhibition present in a population of children with PANS.

Has adult sleep duration declined over the last 50+ years?

The common assumption that population sleep duration has declined in the past few decades has not been supported by recent reviews, which have been limited to self-reported data. The aim of this review was to assess whether there has been a reduction in objectively recorded sleep duration over the last 50+ years. The literature was searched for studies published from 1960 to 2013, which assessed objective sleep duration (total sleep time (TST)) in healthy normal-sleeping adults. The search found 168 studies that met inclusion criteria, with 257 data points representing 6052 individuals ages 18-88 y. Data were assessed by comparing the regression lines of age vs. TST in studies conducted between 1960 and 1989 vs. 1990-2013. Weighted regression analyses assessed the association of year of study with age-adjusted TST across all data points. Regression analyses also assessed the association of year of study with TST separately for 10-y age categories (e.g., ages 18-27 y), and separately for polysomnographic and actigraphic data, and for studies involving a fixed sleep schedule and participants' customary sleep schedules. Analyses revealed no significant association of sleep duration with study year. The results are consistent with recent reviews of subjective data, which have challenged the notion of a modern epidemic of insufficient sleep.

Louis EK, Duwell EJ, Timm PC, Sandness DJ, Boeve BF, Silber MH. Diagnostic thresholds for quantitative REM sleep phasic burst duration, phasic and tonic muscle activity, and REM atonia index in REM sleep behavior disorder with and without comorbid obstructive sleep apnea

OBJECTIVES

We aimed to determine whether phasic burst duration and conventional REM sleep without atonia (RSWA) methods could accurately diagnose REM sleep behavior disorder (RBD) patients with comorbid OSA.

DESIGN

We visually analyzed RSWA phasic burst durations, phasic, "any," and tonic muscle activity by 3-s mini-epochs, phasic activity by 30-s (AASM rules) epochs, and conducted automated REM atonia index (RAI) analysis. Group RSWA metrics were analyzed and regression models fit, with receiver operating characteristic (ROC) curves determining the best diagnostic cutoff thresholds for RBD. Both split-night and full-night polysomnographic studies were analyzed.

SETTING

N/A.

PARTICIPANTS

Parkinson disease (PD)-RBD (n = 20) and matched controls with (n = 20) and without (n = 20) OSA.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

All mean RSWA phasic burst durations and muscle activities were higher in PD-RBD patients than controls (P < 0.0001), and RSWA associations with PD-RBD remained significant when adjusting for age, gender, and REM AHI (P < 0.0001). RSWA muscle activity (phasic, "any") cutoffs for 3-s mini-epoch scorings were submentalis (SM) (15.5%, 21.6%), anterior tibialis (AT) (30.2%, 30.2%), and combined SM/AT (37.9%, 43.4%). Diagnostic cutoffs for 30-s epochs (AASM criteria) were SM 2.8%, AT 11.3%, and combined SM/AT 34.7%. Tonic muscle activity cutoff of 1.2% was 100% sensitive and specific, while RAI (SM) cutoff was 0.88. Phasic muscle burst duration cutoffs were: SM (0.65) and AT (0.79) seconds. Combining phasic burst durations with RSWA muscle activity improved sensitivity and specificity of RBD diagnosis.

CONCLUSIONS

This study provides evidence for REM sleep without atonia diagnostic thresholds applicable in Parkinson disease-REM sleep behavior disorder (PD-RBD) patient populations with comorbid OSA that may be useful toward distinguishing PD-RBD in typical outpatient populations.

Greatest rapid eye movement sleep atonia loss in men and older age

To determine quantitative REM sleep muscle tone in men and women without REM sleep behavior disorder, we quantitatively analyzed REM sleep phasic and tonic muscle activity, phasic muscle burst duration, and automated REM atonia index in submentalis and anterior tibialis muscles in 25 men and 25 women without REM sleep behavior disorder. Men showed significantly higher anterior tibialis phasic muscle activity. Higher phasic muscle activity was independently associated with male sex and older age in multivariate analysis. Men and the elderly may be biologically predisposed to altered REM sleep muscle atonia control, and/or some may have occult neurodegenerative disease, possibly underlying the predominance of older men with REM sleep behavior disorder.

Motor events during healthy sleep: a quantitative polysomnographic study

STUDY OBJECTIVES

Many sleep disorders are characterized by increased motor activity during sleep. In contrast, studies on motor activity during physiological sleep are largely lacking. We quantitatively investigated a large range of motor phenomena during polysomnography in physiological sleep.

DESIGN

Prospective polysomnographic investigation.

SETTING

Academic referral sleep laboratory.

PARTICIPANTS

One hundred healthy sleepers age 19-77 y were strictly selected from a representative population sample by a two-step screening procedure.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Polysomnography according to American Academy of Sleep Medicine (AASM) standards was performed, and quantitative normative values were established for periodic limb movements in sleep (PLMS), high frequency leg movements (HFLM), fragmentary myoclonus (FM), neck myoclonus (NM), and rapid eye movement (REM)-related electromyographic (EMG) activity. Thirty-six subjects had a PLMS index > 5/h, 18 had a PLMS index > 15/h (90th percentile: 24.8/h). Thirty-three subjects had HFLM (90th percentile: four sequences/night). All subjects had FM (90th percentile 143.7/h sleep). Nine subjects fulfilled AASM criteria for excessive FM. Thirty-five subjects had NM (90th percentile: 8.8/h REM sleep). For REM sleep, different EMG activity measures for the mentalis and flexor digitorum superficialis muscles were calculated: the 90th percentile for phasic mentalis EMG activity for 30-sec epochs according to AASM recommendation was 15.6%, and for tonic mentalis EMG activity 2.6%. Twenty-five subjects exceeded the recently proposed phasic mentalis cutoff of 11%. None of the subjects exceeded the tonic mentalis cutoff of 9.6%.

CONCLUSION

Quantification of motor phenomena is a basic prerequisite to develop normative values, and is a first step toward a more precise description of the various motor phenomena present during sleep. Because rates of motor events were unexpectedly high even in physiological sleep, the future use of normative values for both research and clinical routine is essential.

Comparison between an automatic and a visual scoring method of the chin muscle tone during rapid eye movement sleep

OBJECTIVE

To compare two different methods, one visual and the other automatic, for the quantification of rapid eye movement (REM) sleep without atonia (RSWA) in the diagnosis of REM sleep behavior disorder (RBD).

METHODS

Seventy-four RBD patients (mean age, 62.14±9.67 years) and 75 normal controls (mean age, 61.04±12.13 years) underwent one night video-polysomnographic recording. The chin electromyogram (EMG) during REM sleep was analyzed by means of a previously published visual method quantifying the percentage of 30s epochs scored as tonic (abnormal, > or =30%) and that of 2s mini-epochs containing phasic EMG events (abnormal, > or =15%). For the computer quantitative analysis we used the automatic scoring algorithm known as the atonia index (abnormal, <0.8). The percentage correct classification, sensitivity, specificity, and Cohen kappa were calculated.

RESULTS

The atonia index correctly classified 82.6% of subjects, similar to the percentage of correct classifications with individual components of the visual analysis (83.2% each for tonic and phasic), and the combined visual parameters (85.9%). The sensitivity and specificity of automatic analysis (84% and 81%) was similar to the combined visual analysis (89% and 83%). The correlation coefficient between the automatic atonia index and the percentage of visual tonic EMG was high (r = -0.886, P<0.00001), with moderately high correlation with the percentage of phasic EMG (r = -0.690, P<0.00001). The agreement between atonia index and the visual parameters (individual or combined) was approximately 85% with Cohen's kappa, ranging from 0.638 to 0.693.

CONCLUSION

Sensitivity, specificity, and correct classifications were high with both methods. Moreover, there was general agreement between methods, with Cohen's kappa values in the 'good' range. Given the considerable practical advantages of automatic quantification of REM atonia, automatic quantification may be a useful alternative to visual scoring methods in otherwise uncomplicated polysomnograms.

Rapid eye movement sleep behavior disorder: devising controlled active treatment studies for symptomatic and neuroprotective therapy--a consensus statement from the International Rapid Eye Movement Sleep Behavior Disorder Study Group

OBJECTIVES

We aimed to provide a consensus statement by the International Rapid Eye Movement Sleep Behavior Disorder Study Group (IRBD-SG) on devising controlled active treatment studies in rapid eye movement sleep behavior disorder (RBD) and devising studies of neuroprotection against Parkinson disease (PD) and related neurodegeneration in RBD.

METHODS

The consensus statement was generated during the fourth IRBD-SG symposium in Marburg, Germany in 2011. The IRBD-SG identified essential methodologic components for a randomized trial in RBD, including potential screening and diagnostic criteria, inclusion and exclusion criteria, primary and secondary outcomes for symptomatic therapy trials (particularly for melatonin and clonazepam), and potential primary and secondary outcomes for eventual trials with disease-modifying and neuroprotective agents. The latter trials are considered urgent, given the high conversion rate from idiopathic RBD (iRBD) to Parkinsonian disorders (i.e., PD, dementia with Lewy bodies [DLB], multiple system atrophy [MSA]).

RESULTS

Six inclusion criteria were identified for symptomatic therapy and neuroprotective trials: (1) diagnosis of RBD needs to satisfy the International Classification of Sleep Disorders, second edition, (ICSD-2) criteria; (2) minimum frequency of RBD episodes should preferably be ⩾2 times weekly to allow for assessment of change; (3) if the PD-RBD target population is included, it should be in the early stages of PD defined as Hoehn and Yahr stages 1-3 in Off (untreated); (4) iRBD patients with soft neurologic dysfunction and with operational criteria established by the consensus of study investigators; (5) patients with mild cognitive impairment (MCI); and (6) optimally treated comorbid OSA. Twenty-four exclusion criteria were identified. The primary outcome measure for RBD treatment trials was determined to be the Clinical Global Impression (CGI) efficacy index, consisting of a four-point scale with a four-point side-effect scale. Assessment of video-polysomnographic (vPSG) changes holds promise but is costly and needs further elaboration. Secondary outcome measures include sleep diaries; sleepiness scales; PD sleep scale 2 (PDSS-2); serial motor examinations; cognitive indices; mood and anxiety indices; assessment of frequency of falls, gait impairment, and apathy; fatigue severity scale; and actigraphy and customized bed alarm systems. Consensus also was established for evaluating the clinical and vPSG aspects of RBD. End points for neuroprotective trials in RBD, taking lessons from research in PD, should be focused on the ultimate goal of determining the performance of disease-modifying agents. To date no compound with convincing evidence of disease-modifying or neuroprotective efficacy has been identified in PD. Nevertheless, iRBD patients are considered ideal candidates for neuroprotective studies.

CONCLUSIONS

The IRBD-SG provides an important platform for developing multinational collaborative studies on RBD such as on environmental risk factors for iRBD, as recently reported in a peer-reviewed journal article, and on controlled active treatment studies for symptomatic and neuroprotective therapy that emerged during the 2011 consensus conference in Marburg, Germany, as described in our report.

Night-to-night variability of automatic quantitative parameters of the chin EMG amplitude (Atonia Index) in REM sleep behavior disorder

STUDY OBJECTIVES

To analyze the night-to-night variability of REM sleep electromyographic (EMG) features of REM sleep behavior disorder (RBD) by using the automatic quantitative method known as atonia index (AI), and to evaluate the improvement in sensitivity and specificity of AI for the diagnosis of RBD when a second recording night is available.

SETTING

Sleep research center.

INTERVENTIONS

N/A.

METHODS

A group of 17 idiopathic RBD patients was recruited for whom 2 all-night polysomnographic (PSG) recordings were available. Thirty normal controls were also recruited and subgrouped into Young (< 45 years of age) or Aged (> 45 years). Chin EMG analysis was run on all recordings; night-to-night variability of both AI and number of chin EMG activations/h during REM sleep was additionally quantified as the absolute difference between the 2 nights standardized as the percentage of their mean.

MEASUREMENTS AND RESULTS

Night-to-night variability of AI was higher in RBD patients (19.7%) than in the 2 groups of controls (Young 1.8% and Aged 2.8%). The values of variability of chin EMG activations were much higher than those of AI, especially in the Aged controls. Sensitivity of AI ≤ 0.9 for RBD was always higher than 82% and reached 88.9% for the combined-night analysis; specificity was also high, with a value of 92.3% for the combined-value analysis.

CONCLUSION

The night-to-night variability of AI seems to be very low in normal controls and remains under 20% in RBD patients; that of the number of EMG activations is higher. However, even a single PSG recording provides high values of sensitivity and specificity when a threshold value of AI ≤ 0.9 is used to define abnormal chin EMG levels during REM sleep that increase only moderately when a second night recording is available.

REM sleep behavior disorder and REM sleep without atonia as an early manifestation of degenerative neurological disease

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by repeated episodes of dream enactment behavior and REM sleep without atonia (RSWA) during polysomnography recording. RSWA is characterized by increased phasic or tonic muscle activity seen on polysomnographic electromyogram channels. RSWA is a requisite diagnostic feature of RBD, but may also be seen in patients without clinical symptoms or signs of dream enactment as an incidental finding in neurologically normal individuals, especially in patients receiving antidepressant therapy. RBD may be idiopathic or symptomatic. Patients with idiopathic RBD often later develop other neurological features including parkinsonism, orthostatic hypotension, anosmia, or cognitive impairment. RSWA without clinical symptoms as well as clinically overt RBD also often occurs concomitantly with the α-synucleinopathy family of neurodegenerative disorders, which includes idiopathic Parkinson disease, Lewy body dementia, and multiple system atrophy. This review article considers the epidemiology of RBD, clinical and polysomnographic diagnostic standards for both RBD and RSWA, previously reported associations of RSWA and RBD with neurodegenerative disorders and other potential causes, the pathophysiology of which brain structures and networks mediate dysregulation of REM sleep muscle atonia, and considerations for the effective and safe management of RBD.