Dream Enactment Behavior Research Articles

Dream Enactment Behaviors Associated With Posttraumatic Stress Disorder.

The investigators aimed to draw attention to current debates surrounding the etiologies of dream enactment behaviors in patients with posttraumatic stress disorder (PTSD). The phenomenological overlap between PTSD-related nocturnal symptoms, rapid eye movement sleep behavior disorder (RBD), and trauma-associated sleep disorder (TASD) is discussed. Strategies used to diagnose and manage dream enactment behaviors, whether due to RBD or another confounding sleep disorder, are considered. Finally, the need for further research on the pathophysiological overlap and integrated treatment of PTSD, RBD, and, possibly, TASD is highlighted.

Sleep Disturbances and Phenoconversion in Patients with REM Sleep Behavior Disorder.

Objective: We aimed to investigate relationships between sleep disturbances and phenoconversion to neurodegenerative diseases in patients with REM sleep behavior disorder (RBD). Method: Using a comprehensive sleep database in a university-affiliated hospital between December 2014 and March 2021, we reviewed the data of 226 patients with RBD (182 patients with idiopathic RBD (iRBD) and 44 patients with symptomatic RBD (sRBD) with a neurodegenerative disease). Results: Among 226 patients with RBD (male, 61.5%), the mean age at RBD onset and mean disease duration were 59.4 ± 10.5 and 5.9 ± 5.6 years, respectively. Further, 111 (49.1%) patients had periodic limb movements during sleep (PLMS, PLM index ≥ 15/h), while 110 patients (48.7%) had comorbid obstructive sleep apnea (OSA, respiratory disturbance index ≥ 15/h). There was a positive correlation between age at RBD onset and the apnea-hypopnea index and Pittsburgh Sleep Quality Index. Compared to patients with iRBD, patients with sRBD showed a lower N3 sleep (3.3 ± 5.0 vs. 1.6 ± 3.1%, p = 0.004) and higher periodic limb movement index (36.3 ± 31.8 vs. 56.9 ± 47.5/h, p = 0.021) at the baseline. Among the 186 patients with iRBD, 18 (8.0%) developed neurodegenerative diseases (converters, mean follow-up duration: 2.5 ± 1.6 years) and 164 did not (non-converters, mean follow-up 2.4 ± 2.2 years). There was no significant between-group difference in the demographics and baseline clinical features. Continuous positive airway pressure (CPAP) therapy was prescribed in 101 patients with OSA; among them, 71 (70%) patients agreed to use it. CPAP improved dream enactment behaviors. Conclusion: In our study, 8.0% of patients with iRBD showed phenoconversion within a mean follow-up duration of 2.5 years. Polysomnographic parameters could not predict phenoconversion to neurodegenerative disease. However, approximately half of the patients with RBD presented with significant sleep disorders, including OSA or PLMS. CPAP therapy may alleviate RBD symptoms in patients with RBD-OSA.

P077 Reliability of the Clinical Characterization of Isolated REM Sleep Behavior Disorder

Abstract Purpose Compare agreements between polysomnography-based (PSG) diagnosis of isolated REM-sleep-behavior-disorder (iRBD) and Non-REM-Hypertonia (NRH), a novel biomarker independently associated with synucleinopathy-related neurodegenerative diseases. Methods Sixteen patients with histories of dream-enactment-behavior (DEB)(women=38%; age:64.6±13.0) underwent PSG with simultaneously-recorded Sleep Profiler (SP). Two boarded sleep neurologists independently characterized iRBD. Physician1 combined abnormal qualitative REM-sleep-without-atonia (RSWA) by submental electromyography, with video-confirmation of probably DEB. Physician2 relied solely on qualitative RSWA. SP was auto-staged, technically reviewed, and reprocessed for automated abnormal NRH detection. Kappa scores measured physician and NRH agreements. Results In the 14 records with REM sleep, iRBD was characterized in: Physician1=64%, Physician2=79%, NRH=71% of the records. Across the three methods, unanimous iRBD agreement occurred in 57% of the records (positive=7, negative=1). The between-physician agreement in iRBD classifications was fair (kappa=0.32). The agreement between NRH and Physician1 was moderate (kappa=0.52) versus slight with Physician2 (kappa=0.05). NRH comparisons to consensus physician agreement yielded one false-positive and one false-negative iRBD finding. Physician2 classified: a) iRBD in two cases that were negative by Physician1 and NRH, and b) one negative case that Physician1 and NRH characterized as iRBD. Physician1 identified one negative case that was classified iRBD by Physician2 and NRH. Additionally, NRH was abnormal in one of the two records with no REM sleep. Discussion NRH may assist in iRBD risk assessment, given it agreed with at least one physician in 86% of the cases and the between-physician iRBD agreement was only fair. NRH also characterized iRBD-risk in patients with insufficient REM sleep for RSWA assessment.

Melatonin as first‐line treatment for sleep disorders in Parkinson's disease?

Sleep disturbance has been reported in up to 88%–98% of Parkinson's disease patients; various sleep disorders can present even before motor symptoms. Rapid eye movement sleep behaviour disorder (RBD), which can lead to violent dream enactment behaviour, has a prevalence in Parkinson's disease of 20% to 50% but best management of the condition is unclear. Here, the authors consider whether melatonin is an effective pharmacological option to manage RBD.

527 Patient-Reported Treatment Outcomes in the Mayo Clinic REM Sleep Behavior Disorder Registry: Efficacy of Melatonin and Clonazepam

Abstract Introduction REM sleep behavior disorder (RBD) is characterized by disruptive, violent dream enactment behaviors (DEB), necessitating symptomatic treatment to prevent injury and reduce DEB frequency and severity. Melatonin and clonazepam are regarded as RBD therapeutic mainstays, although outcomes data remains limited. We surveyed RBD patients to determine their outcomes following melatonin, clonazepam, and melatonin-clonazepam combination therapy. Methods Mayo Clinic RBD Patient Registry participants received an electronic survey concerning treatment type(s) and dose(s), efficacy, and adverse effects. The primary outcome was treatment efficacy, determined by comparing DEB frequency/severity ratings on a visual analog scale (VAS). Adverse effects severity was assessed by Likert scales. We comparatively analyzed VAS before and after treatment and adverse effects between treatments using non-parametric statistical tests. Results Sixty-eight of 109 patients responded (62.3%; 64 had analyzable data) with a mean age of 67.7 years. Fifty-seven (85%) were men, with mean RBD symptom duration of 13.9 years. Patients receiving each treatment were: melatonin=30, clonazepam=8, and combination=12; 14 received other or no treatment. Baseline VAS ratings were similar between groups. Only melatonin (p=0.003) and combination therapy (p=0.039) improved VAS ratings; clonazepam monotherapy did not improve VAS. Only melatonin monotherapy was reported to lower VAS compared to untreated patients (p=0.02). Optimally effective mean dosages were melatonin 9.95±5.06 mg and clonazepam 0.81±0.48 mg. Patient frequencies reporting one or more moderately-severe side effect(s) were similar between melatonin (15%), clonazepam (7%), and combination therapies (9%). Twenty-five (36.8%) patients had received only one medication trial, while 41.2% required more than one medication. Of these, 15 (22.1%) tried 2 and 13 (19.1%) tried 3 or more treatments. Conclusion Melatonin therapy at an approximate mean 10 mg dosage improved patient-reported DEB frequency/severity on VAS, compared between both previous intraindividual baseline ratings and with untreated patients, while clonazepam monotherapy did not, without differential adverse effects. Clonazepam monotherapy data were limited. These data inform future prospective melatonin symptomatic therapy trials for RBD. Additionally, 41.2% required more than one RBD pharmacological treatment, suggesting a current therapeutic gap and unmet need for future development of biologically-informed, evidence-based symptomatic RBD therapeutics. Support (if any):

523 Characteristics of Patients with REM Sleep without Atonia/Periodic Limb Movements of Sleep without Dream Enactment Behaviors

Abstract Introduction While REM sleep without atonia (RSWA) in REM sleep behavior disorder (RBD) is associated with male sex, age greater than or equal to 50 years, alpha-synucleinopathies, and narcolepsy, the characteristics of patients with RSWA/persistent periodic limb movements of sleep in REM sleep (RSWA/PLMS-REM) without dream enactment behaviors are unexplored. The aim of this study was to compare the demographics, comorbidities, and concomitant medication use between RSWA/PLMS-REM patients and non-RSWA/non-PLMS-REM controls. Based on anecdotal clinical observations, we hypothesized that these patients are more commonly young, women, have psychiatric or neurological diseases, and use antidepressants. Methods We conducted a retrospective review of the Mayo Clinic electronic medical record to identify all patients with RSWA/PLMS-REM between November 2018 and November 2020. After excluding all patients with RBD, restless legs syndrome, narcolepsy, and RSWA/non-PLMS-REM, we identified 27 patients. All in-lab polysomnograms (PSGs) were reviewed to calculate the periodic limb movement index per hour of REM sleep (REM-PLMI). We also identified a control group of 15 individuals without RSWA, reviewed their PSGs, and calculated the REM-PLMI. Results The mean REM-PLMI of patients with RSWA was 64 +/- 8.3 (standard error of mean (SEM)) per hour versus 1 +/- 0.6 (SEM) per hour in non-RSWA controls (p < 0.001). Patients with RSWA/PLMS-REM and non-RSWA controls had similar age and gender, 62 +/- 3 (SEM) versus 58 +/- 3 (SEM) years and 81% versus 87% men, respectively. However, psychiatric diagnosis, neurological disorders, and antidepressants use were more common among RSWA/PLMS-REM patients compared to non-RSWA controls with p = 0.0002, p = 0.0035 and p = 0.0074 respectively (Fisher’s Exact Test). Conclusion Psychiatric diagnosis, neurological disorders, and antidepressant use are more common among RSWA/PLMS-REM patients compared to non-RSWA/non-PLMS-REM controls. Further research to determine the implications of a diagnosis of RSWA/PLMS-REM for the future development of alpha-synucleinopathies are needed and currently ongoing. Support (if any):

525 A population-based study of phenoconversion to parkinsonism from REM sleep behavior: a Population-based Study in the CLSA

Abstract Introduction To date, studies have estimated the phenoconversion rate from sleep clinics, using polysomnography proven RBD. However, no population-based estimates have been reported, testing to what degree possible RBD, screened by questionnaire is associated with increased risk of neurodegeneration. Methods We included those aged 45–85 years, living in one of 10 Canadian provinces in between 2012–2015 (at the baseline), recruited via three population-based sampling methods. Dream enactment behavior/possible RBD was screened using the RBD1Q single question-questionnaire. De-novo parkinsonism was defined as free of pre-existing diagnosis at the baseline with a ‘new’ diagnosis at the follow-up (205–2019). Relative risk (log-binomial regression), hazard ratio (Cox regression), incidence rate (Poisson regression) between the affected group and the symptom naïve group were assessed, adjusting for age and sex (and total years of education and language). Results Overall, 58 participants phenoconverted into parkinsonism and 53 into dementia at the follow-up (mean intervals=3.06±0.37 years). Participants with dream enactment behavior had 2.75 times higher risk to phenoconvert into parkinsonism than the symptom-free. Similarly, those with dream enactment behavior at the baseline possessed higher risk to screening positive of parkinsonism. No difference in time to phenoconversion was found between groups, The results remained robust after excluding non-RBD related symptoms, such as apnea and non-REM sleep parasomnia. Conclusion Compared to symptom-free, those with pRBD had higher risk to developing parkinsonism in near future. Support (if any):

528 REM Sleep Without Atonia in Idiopathic REM Sleep Behavior Disorder in the North American Prodromal Synucleinopathy Cohort

Abstract Introduction Idiopathic/isolated REM sleep behavior disorder (iRBD) is a prodromal alpha-synucleinopathy characterized by dream enactment behavior and REM sleep without atonia (RSWA). We sought to define quantitative RSWA diagnostic thresholds in the North American Prodromal Synucleinopathy (NAPS) Consortium cohort. We analyzed RSWA between iRBD patients across participating NAPS sleep centers, compared to normative controls, and hypothesized that previous diagnostic RSWA thresholds were overestimates. Methods All digital polysomnography files were converted to European Data Format and scored at a central laboratory (Mayo Clinic) which standardized display scoring montages, channel sensitivities, and filtering, and scripted computational analyses for visual scoring. RSWA was quantitatively analyzed in the submentalis (SM) and anterior tibialis (AT) muscles in iRBD (n=86) patients and controls (n=118) utilizing well validated visual (Mayo) and automated (RAI) methods. Parametric statistics were used to compare RSWA metrics, and RSWA thresholds were developed using receiver operating characteristic curves. Results RSWA was significantly higher for the RAI and all visual individual and combined muscle activity metrics in iRBD compared to controls (all p<0.001). Average SM phasic measures were: 14.2% (Mayo), 17.9% (McGill), 18.5% (UCLA), and 9.4% (Washington University). Average AT phasic measures at each site were: 26.7% (Mayo), 17.1% (McGill), 23.3% (UCLA), and 17.4% (Washington University). Average SM/AT ‘any’ measures at each site were: 45.4% (Mayo), 35.9% (McGill), 53.4% (UCLA), and 23.5% (Washington University). Overall cohort RBD diagnostic thresholds (AUC, specificity/sensitivity) were: SM phasic 4.9% (90.0, 82.2%/83.7%); AT phasic 7.6% (88.7%, 82.2%/81.4%) and combined SM/AT ‘any’ 13% (94.6, 83.9%/96.5%). Conclusion RSWA thresholds in the NAPS cohort were substantially lower than previously reported, suggesting previously overestimated diagnostic RSWA thresholds due to smaller, enriched patient samples and overfit statistical modeling. Confirmation of these findings in the complete NAPS cohort (n=300 iRBD patients across all 10 NAPS centers) is planned. Support (if any):

831 Diagnostic and Treatment Challenges in a Child with Type 1 Narcolepsy

Abstract Introduction The diagnosis and management of Narcolepsy can be challenging in young children. We present a case of abrupt onset severe type 1 narcolepsy complicated by tactile hallucinations with stimulant medication therapy. Report of case(s) A previously healthy 7-year-old African American female presented to us at the beginning of the current pandemic with one week of excessive daytime sleepiness (EDS) with associated enuresis, hyperphagia and two episodes of cataplexy. She also presented with hypnagogic hallucinations and dream enactment behaviors. She was extremely sleepy with a score of 24/24 on the Epworth Sleepiness Scale. Her neurological exam was negative except for facial twitching appearing to be cataplectic facies. Extensive work up including urine toxicology, serology and cerebrospinal fluid (CSF) tests were undertaken to rule out infectious and demyelinating conditions; the results of these tests were negative. Brain magnetic resonance imaging as well as electroencephalogram testing were unremarkable. Overnight polysomnography demonstrated short sleep latency and rapid eye movement (REM) sleep without atonia and a multiple sleep latency test showed a mean sleep latency of less than 2 minutes and 4/4 sleep onset REM periods, highly suggestive of narcolepsy. Her HLA DQB1*0602 haplotype was positive but CSF Hypocretin testing was not done. She was given a diagnosis of Narcolepsy type I and started treatment on low dose Methylphenidate and Venlafaxine to address her EDS and cataplexy, respectively. Her EDS was gradually controlled with a higher dose of Methylphenidate but she developed severe tactile hallucinations. She complained of feeling bugs crawling under her skin and could not keep her clothes on due to constant discomfort. The tactile hallucinations improved with discontinuation of methylphenidate but reappeared with introduction of a different class of stimulants. Modafinil was ineffective in controlling her EDS symptoms. Her EDS, cataplexy and enuresis were better controlled after starting her on Sodium Oxybate. She continues to suffer from moderate to severe EDS with optimally dosed Sodium Oxybate with suboptimal response to various typical and atypical stimulants. Conclusion This case illustrates the difficulties in diagnosing and treating pediatric narcolepsy patients and a unique challenge of tactile hallucinations with stimulant medications. Support (if any):

533 Characteristics of patients with REM sleep without atonia (RSWA)/persistent periodic limb movements of sleep (PLMS) in REM sleep

Abstract Introduction While RSWA in REM sleep behavior disorder (RBD) is associated with male sex, age > 50 years, alpha-synucleinopathies, and narcolepsy, the characteristics of patients with RSWA/PLMS in REM sleep (RSWA/PLMS-REM) without dream enactment behaviors are unexplored. The aim of this study was to compare the demographics, comorbidities and concomitant medication use between RSWA/PLMS-REM patients and non-RSWA/non-PLMS-REM controls. Based on anecdotal clinical observations we hypothesized that these patients are more commonly young, women, have psychiatric or neurological diseases, and use antidepressants. Methods We conducted a retrospective review of the Mayo Clinic electronic medical record to identify all patients with RSWA/ PLMS-REM between November 2018 and November 2020. After excluding all patients with RBD, restless legs syndrome, narcolepsy and RSWA/non-PLMS-REM we identified 27 patients. All PSGs were reviewed to calculate the periodic limb movement index per hour of REM sleep (REM-PLMI). We also identified a covenience sample of 15 non-RSWA controls, reviewed their PSGs and calculated REM-PLMI. Results The mean REM-PLMI of patients with RSWA was 64+/-8.3 (SEM)/hour versus 1+/-0.6 (SEM)/hours in non-RSWA controls (p< 0.001). Patients with RSWA/PLMS-REM and non-RSWA controls had similar age and gender, 62 +/- 3 (SEM) versus 58 +/-3 (SEM) years and 81% versus 87% men, respectively. However psychiatric diagnosis, neurological disorders and antidepressants use was more common among RSWA/PLMS-REM patients compared to non-RSWA controls, p=0.0002, p=0.0035 and p=0.0074, respectively. (Fisher’s Exact Test) Conclusion Psychiatric diagnosis, neurological disorders and antidepressant use are more common among RSWA/PLM-REM patients compared to non-RSWA controls. Further research to determine the implications of a diagnosis of RSWA/PLMS-REM for the future development of alpha-synucleinopathies are needed and currently ongoing. Support (if any):

Recent Update on Treatment and Management of Rapid Eye Movement Sleep Behavior Disorder

Rapid eye movement sleep behavior disorder (RBD) is a parasomnia that is characterized by dream-enactment behavior, which can often result in sleep related injury. RBD is strongly associated with neurodegenerative disease especially with alpha-synucleinopathy. More than 70% of the patients convert to neurodegenerative disease including Parkinson’s disease or diffuse Lewy body dementia with a median period of 7.5 years. Treatment for RBD is currently focused on symptomatic treatment to prevent the injury. First step is establishing safe sleep environment to avoid injury. Clonazepam and melatonin are most commonly used medication for symptomatic treatment for RBD, however, well-designed randomized clinical trials are lacking. Prognostic counselling with longitudinal follow-up is also crucial in managing patients with RBD, which should be individualized for each patient with regular systematic follow-up evaluation.

Dream Enactment Behavior Disorder Associated with Pallido-Nigro-Luysian Degeneration and Tau Proteinopathy.

Pallido-nigro-luysian atrophy (PNLA) is a rare neurodegenerative disorder with only a few cases reported to date. Although the clinical picture usually resembles progressive supranuclear palsy, pathological examination reveals more selective atrophy and loss of neurons in the globus pallidus, substantia nigra and subthalamic nucleus. To describe the clinical features and pathological findings of a patient with PNLA. Case report with clinico-pathological discussion. An 83-year-old man presented to our clinic with a vertical supranuclear gaze palsy, parkinsonism, gait impairment and sleep abnormalities suggestive of REM-sleep behavior disorder. Neuropathological examination 5 years after symptom onset revealed subcortical tau proteinopathy compatible with a PNLA pattern. There was also an associated mild degree of limbic/subcortical inflammatory response, Alzheimer's disease-related changes, as well as argyrophilic grain disease. We present a comprehensive clinico-pathological discussion of a patient with PNLA. Besides parkinsonism and vertical supranuclear gaze palsy, the patient also had a sleep disorder, clinically suggestive of REM behavioral disorder, which has not been previously reported in PNLA. We expand the clinical phenotype of this rare condition and provide neuropathological evidence for the associated abnormalities.

Is REM sleep behavior disorder a friend or foe of obstructive sleep apnea? Clinical and etiological implications for neurodegeneration

REM sleep behavior disorder (RBD) is a parasomnia characterized by loss of muscle atonia during REM sleep, associated with complex motor enactment of dreams. Obstructive sleep apnea (OSA) is a relatively common sleep disorder characterized by repetitive episodes of upper airway obstruction while sleeping, which can result in hypoxemia and sleep fragmentation. Even though the nature of RBD and OSA is different, OSA may sometimes be accompanied by RBD symptoms. Accordingly, it is reasonable to distinguish these two sleep disorders in subjects with dream enactment behaviors. Although RBD and OSA share similar sleep phenomena, their association has yet to be elucidated. Herein, we draw attention to various RBD mimicking conditions, RBD combined with OSA, and the relationship between RBD and OSA. Furthermore, the clinical implications of OSA in neurodegeneration and the optimized management of RBD combined with OSA are also discussed in this review.

The role of pedunculopontine nucleus in isolated REM sleep behavior disorder and REM sleep without atonia

IntroductionThe aim of this study was to analyze the functions of pedunculopontine nucleus (PPN) in isolated REM sleep behavior disorder (iRBD) and REM sleep without atonia (RSWA) to investigate the role of PPN in dream-enacting motor behaviors in RBD. We evaluated the activity of PPN through the prepulse modulation (PPM) together with other brainstem reflexes to investigate the differences in changes at brainstem. MethodsWe included nine patients with isolated RSWA and 10 patients with iRBD. For diagnosis, all patients underwent polysomnography. None of the patients had parkinsonism or dementia. We also included 17 healthy participants with similar age and sex. Blink reflex (BR), PPM of BR, recovery excitability of BR, and auditory startle reflex (ASR) were recorded in all participants. ResultsThere was a prepulse inhibition deficit in iRBD and RSWA groups compared to healthy subjects. The BR-R2 recovery at 200 ms interval was also higher in patients with iRBD and RSWA. In ASR recordings, the response probabilities were higher in the RBD group compared to RSWA and control groups. ConclusionThe PPM was abnormal in both iRBD and RSWA whereas ASR was enhanced in iRBD. We suggest that there are certain similarities and differences in the pathophysiologies of iRBD and RSWA.

The "respiratory REM sleep without atonia benefit" on coexisting REM sleep behavior disorder - obstructive sleep apnea.

Rapid eye movement sleep behavior disorder (RBD) is a parasomnia characterized by dream-enactment behaviors that emerge during a loss of REM sleep atonia. In patients with RBD, obstructive sleep apneas syndrome (OSAS) frequently occurs as a comorbid entity. It has been reported that the presence of muscle tone during REM sleep (REM sleep without atonia-RSWA) could play a protective role in patients with OSAS RBD. In OSAS, recurrent episodes of complete or partial collapse of the upper airway occur during both, NREM and REM sleep. Particularly during sleep, the withdrawal of excitatory noradrenergic and serotoninergic inputs to the upper airway motor neurons deeply reduces the pharyngeal muscle activity, increasing the propensity for superior airway collapse. The present study compared for the first time the impact of OSAS in RBD patients with a subtype of OSAS patients with predominantly or isolated REM sleep-related OSAS (OSAS REM group) in the search of an adequate model to evaluate future therapeutic strategies. Our study found a significant lower nadir of oximetry values in OSAS RBD in comparison with the OSAS REM group. This reduction, that we called the “respiratory RSWA benefit”, is in accordance with the decrease of the nadir oximetry values observed in patients with Parkinson disease and OSAS with or without RBD. We suggest that the group of OSAS REM patients is a natural model to evaluate the respiratory protective role of RSWA in patients with coexisting RBD-OSAS and Parkinson’s disease.

Striatal Dopaminergic Deficit and Sleep in Idiopathic Rapid Eye Movement Behaviour Disorder: An Explorative Study.

IntroductionIdiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is increasingly recognised as an important precursor disease state of alpha-synucleinopathies. This parasomnia is characterized by a history of recurrent nocturnal dream enactment behaviour, loss of skeletal muscle atonia, and increased phasic muscle activity during REM sleep. Neuroimaging studies of striatal dopamine transporter uptake tracer signaling suggest increasing dopaminergic deficit across the continuum of the alpha-synucleinopathies, with early sleep dysfunction suggestive of early caudate dysfunction. Henceforth, we set out to investigate the relationship between early sleep changes and the striatal dopaminergic availability in iRBD.MethodsTwelve patients with iRBD, who had undergone a video polysomnography and a neuroimaging assessment of striatal dopamine transporter (DaT) uptake tracer signaling, and 22 matched controls who had similarly undergone a video polysomnography were retrospectively identified. Data were statistically analyzed to identify altered sleep parameters and correlate them with striatal dopamine transporter uptake tracer signaling.ResultsThe iRBD patients exhibited an increased number of periodic limb movements during sleep (P=0.001), compared to 22 age-matched healthy subjects. In addition, several significant links were found between regional DaT-uptakes and sleep architecture. Correlational analyses suggested a strong positive association between sleep fragmentation and dopamine deficiency in left caudate (r=−0.630, P=0.028), whilst an increased uptake in the whole striatum was strongly linked to the sleep efficiency, and to a lesser degree to the length of sleep duration.DiscussionTo the best of our knowledge, this is the first demonstration of a close relationship between dopaminergic availability in striatum and the quality of sleep in iRBD. Taken together, our exploratory findings suggest that subtle but functionally significant striatal changes in early stages of iRBD may contribute to the further shaping of sleep architecture.

The Association between History of Body Injury during Sleep and Obstructive Sleep Apnea in REM Sleep Behavior Disorder

Objectives To investigate whether a history of body injury is associated with obstructive sleep apnea (OSA) in patients with rapid eye movement (REM) sleep behavior disorder (RBD). Methods We enrolled 56 consecutive patients with RBD, a history of dream-enacting behaviors, and polysomnographic evidence of REM sleep without atonia. Participants were asked whether they had any history of body injuries such as self-injury or bed-partner injury during sleep. The demographic characteristics and polysomnographic parameters of the groups with a history of injury (n=34, 60.7%) and without (n=22, 39.3%) were compared. The association between the history of injury and OSA was assessed. Results OSA [apnea-hypopnea index (AHI) ≥5/h) was associated with a history of body injury [odds ratio (OR)=6.25, 95% confidence interval (CI)=1.64–23.84]. Additionally, the logistic regression analysis showed that insomnia severity index (OR=0.87, 95% CI=0.80–0.98) and AHI (OR=1.10, 95% CI=1.02–1.18) were associated with history of body injury. Conclusions Therefore, we can conclude that history of body injury is related to obstructive sleep apnea in patients with RBD. Keywords: REM sleep behavior disorder, Obstructive sleep apnea, Injuries

Quantitative REM Sleep without Atonia in Parkinson's Disease and Essential Tremor.

Rapid eye movement (REM) sleep behavior disorder (RBD) occurs occasionally in essential tremor (ET), but polysomnographic REM sleep without atonia (RSWA) analyses have been sparse. To characterize the amount and distribution of polysomnographic RSWA, the electrophysiologic substrate of RBD, in patients with Parkinson's disease (PD) and ET. We analyzed quantitative RSWA in 73 patients: PD (23), ET (23), and age-sex-matched controls (27). None had dream-enactment behavior history or received antidepressants. Phasic, tonic, "any," and phasic-burst duration RSWA measures were calculated in the submentalis (SM) and anterior tibialis (AT) muscles. The automated REM atonia index (RAI) was also determined. Statistical analysis was performed by Kruskal-Wallis rank-sum and Mann-Whitney tests. SM phasic RSWA was significantly greater for PD than ET patients and controls (12.5% ± 12.8% vs. 4.9% ± 6.7%, 3.9% ± 2.6%), as was SM "any" (13.54% ± 14.30% vs. 5.2% ± 7.6%, 4.2% ± 2.6%). RAI was significantly lower in PD than in ET and controls (0.78 ± 0.23 vs. 0.92 ± 0.09 vs. 0.90 ± 0.17, P ≤ 0.005), but no different between ET and controls. AT phasic and "any" RSWA was similar between the 3 groups. ET and control RSWA was similar in all measures. Two ET patients (8.7%) had SM RSWA similar to PD patients. Elevated SM RSWA distinguished PD from ET in patients without dream-enactment symptoms and occurs frequently in PD patients, and in isolated tremor suggests underlying synucleinopathy. Prospective studies will further validate these findings.

Clinician-Focused Overview and Developments in Polysomnography.

Purpose of ReviewPolysomnography (PSG) represents a fundamental diagnostic tool used in the evaluation of sleep disorders. It represents a simultaneous recording of sleep staging, eye movements, electromyographic tone, respiratory parameters, and electrocardiogram. It is particularly helpful in the assessment of sleep-disordered breathing and its management, propensity for excessive sleepiness, complex behaviors during sleep, including motor disturbances of sleep, sleep-related epilepsy, and parasomnias. This review is intended to summarize the indications for PSG, the limitations and challenges of this diagnostic tool, indications for home sleep apnea testing options, and new developments and trends in polysomnography.Recent FindingsThe polysomnogram is fundamentally important in the evaluation of sleep-disordered breathing in the setting of cardiovascular comorbidities and neurologic conditions such as neuromuscular disease, stroke, and epilepsy and in the evaluation of dream enactment behavior in the setting of REM sleep behavior disorder (RBD). Because RBD is predictive of neurodegenerative disorders, recent data highlights the importance of PSG in corroborating the diagnosis of RBD and identifying people who may be at risk. However, due to cost as well as limitations in access to care, further testing has been developed and implemented including the home sleep apnea test (HSAT). The evolution of consumer wearable devices has also been a growing trend in sleep medicine; however, few have received appropriate validation.SummaryPSG has been used in both the clinical and research settings and remains the gold standard clinical diagnostic test for suspected obstructive sleep apnea (OSA) or central sleep apnea (CSA). Clinicians must be familiar with the basic indications for a PSG but also recognize when it is absolutely required. At this time, the PSG is essential in the evaluation of nocturnal hypoventilation disorders of sleep, periodic limb movements of sleep, and central nervous system hypersomnia (in the absence of CSF hypocretin) when combined with the multiple sleep latency test (MSLT) and is probably the only way to help differentiate among complex behaviors during sleep, especially in the setting of RBD. The capacity to establish an early diagnostic risk of potential dementia would be of critical importance once neuroprotective agents become available.

Dream enactment behavior-a real nightmare: a review of post-traumatic stress disorder, REM sleep behavior disorder, and trauma-associated sleep disorder.

Dream enactment behavior is a phenomenon demonstrated in patients with post-traumatic stress disorder, rapid eye movement sleep behavior disorder, as well as with a more recently described condition entitled trauma-associated sleep disorder, which shares diagnostic criteria for rapid eye movement sleep behavior disorder. While these conditions share some commonalities, namely dream enactment behavior, they are quite different in pathophysiology and underlying mechanisms. This review will focus on these 3 conditions, with the purpose of increasing awareness for trauma-associated sleep disorder in particular.