To determine the pathologic substrates in patients with rapid eye movement (REM) sleep behavior disorder (RBD) with or without a coexisting neurologic disorder.
The clinical and neuropathologic findings were analyzed on all autopsied cases from one of the collaborating sites in North America and Europe, were evaluated from January 1990 to March 2012, and were diagnosed with polysomnogram (PSG)-proven or probable RBD with or without a coexisting neurologic disorder. The clinical and neuropathologic diagnoses were based on published criteria.
172 cases were identified, of whom 143 (83%) were men. The mean ± SD age of onset in years for the core features were as follows – RBD, 62 ± 14 (range, 20–93), cognitive impairment (n = 147); 69 ± 10 (range, 22–90), parkinsonism (n = 151); 68 ± 9 (range, 20–92), and autonomic dysfunction (n = 42); 62 ± 12 (range, 23–81). Death age was 75 ± 9 years (range, 24–96). Eighty-two (48%) had RBD confirmed by PSG, 64 (37%) had a classic history of recurrent dream enactment behavior, and 26 (15%) screened positive for RBD by questionnaire. RBD preceded the onset of cognitive impairment, parkinsonism, or autonomic dysfunction in 87 (51%) patients by 10 ± 12 (range, 1–61) years. The primary clinical diagnoses among those with a coexisting neurologic disorder were dementia with Lewy bodies (n = 97), Parkinson’s disease with or without mild cognitive impairment or dementia (n = 32), multiple system atrophy (MSA) (n = 19), Alzheimer’s disease (AD)(n = 9) and other various disorders including secondary narcolepsy (n = 2) and neurodegeneration with brain iron accumulation-type 1 (NBAI-1) (n = 1). The neuropathologic diagnoses were Lewy body disease (LBD)(n = 77, including 1 case with a duplication in the gene encoding α-synuclein), combined LBD and AD (n = 59), MSA (n = 19), AD (n = 6), progressive supranulear palsy (PSP) (n = 2), other mixed neurodegenerative pathologies (n = 6), NBIA-1/LBD/tauopathy (n = 1), and hypothalamic structural lesions (n = 2). Among the neurodegenerative disorders associated with RBD (n = 170), 160 (94%) were synucleinopathies. The RBD-synucleinopathy association was particularly high when RBD preceded the onset of other neurodegenerative syndrome features.
In this large series of PSG-confirmed and probable RBD cases that underwent autopsy, the strong association of RBD with the synucleinopathies was further substantiated and a wider spectrum of disorders which can underlie RBD now are more apparent.
REM sleep behavior disorder; Parasomnia; Lewy body disease; Dementia with Lewy bodies; Parkinson’s disease; Multiple system atrophy; Synuclein; Synucleinopathy
REM sleep behavior disorder (RBD) is a parasomnia characterized by loss of muscle atonia during REM sleep that results in motor behaviors. Diagnosis of RBD involves a clinical interview in which history of dream enactment behaviors is elicited and a subsequent overnight polysomnography (PSG) evaluation to assess for REM sleep without atonia (RWA) and/or observe motor behaviors during REM sleep. Therefore, the nature of RBD diagnosis involves both subjective and objective measurements that attempt to qualify and quantify the different diagnostic sub-criteria.
The primary aim of the current study was to identify and summarize the available clinical measurements that have been used for RBD assessment.
Two major online databases (MEDLINE and PsycInfo) were searched for articles developing, validating, or evaluating psychometric properties of the RBD diagnostic criteria or methods used for diagnosis. Studies of adult subjects (18+) that included sufficient psychometric data for validation were included.
Fifty-eight studies were found to meet review criteria. The objective measurements for assessment of RBD reviewed included visual electromygraphic (EMG) scoring methods, computerized EMG scoring methods, cardiac 123I-MIBG scintigraphy, actigraphy, behavioral classification and video analysis. Subjective measurements of RBD included interviews and questionnaires.
Sleep history may be sufficient for diagnosis of RBD in some populations. However, PSG is necessary for a definitive diagnosis. EMG scoring methods vary in definition used and there is no single accepted approach to scoring muscle activity. Additional validation studies are required for establishing cutoff scores for the different methods. Questionnaires were shown to be appropriate screening tools, yet further validation in different population is necessary.
REM sleep behavior disorder (RBD) is associated with neurodegenerative disease and particularly with the synucleinopathies. Convenience samples involving subjects with idiopathic RBD have suggested an increased risk of incident mild cognitive impairment (MCI), dementia (usually dementia with Lewy bodies) or Parkinson’s disease (PD). There is no data on such risk in a population-based sample.
Cognitively normal subjects aged 70–89 in a population-based study of aging who screened positive for probable RBD using the Mayo Sleep Questionnaire were followed at 15 month intervals. In a Cox Proportional Hazards Model, we measured the risk of developing MCI, dementia, PD among the exposed (pRBD+) and unexposed (pRBD−) cohorts.
Forty-four subjects with pRBD+ at enrollment (median duration of pRBD features was 7.5 years), and 607 pRBD− subjects, were followed prospectively for a median of 3.8 years. Fourteen of the pRBD+ subjects developed MCI and one developed PD (15/44=34% developed MCI / PD); none developed dementia. After adjustment for age, sex, education, and medical comorbidity, pRBD+ subjects were at increased risk of MCI / PD [Hazard Ratio (HR) 2.2, 95% Confidence Interval (95%CI) 1.3 – 3.9; p=0.005]. Inclusion of subjects who withdrew from the study produced similar results, as did exclusion of subjects with medication-associated RBD. Duration of pRBD symptoms did not predict the development of MCI / PD (HR 1.05 per 10 years, 95%CI 0.84 – 1.3; p=0.68).
In this population-based cohort study, we observed that pRBD confers a 2.2-fold increased risk of developing MCI / PD over four years.
sleep disorders; parasomnias; dementia; Alzheimer’s disease; dementia with Lewy bodies; parkinsonism; synuclein
The clinical features of dementia with Lewy bodies (DLB) during wakefulness are well known. Other than REM sleep behavior disorder (RBD), only limited data exists on other sleep disturbances and disorders in DLB. We sought to characterize the polysomnographic (PSG) findings in a series of DLB patients with sleep-related complaints.
Retrospective study of patients with DLB who underwent clinical PSG at Mayo Clinic Rochester or Mayo Clinic Jacksonville over an almost 11 year span for evaluation of dream enactment behavior, excessive nocturnal movements, sleep apnea, hypersomnolence, or insomnia. The following variables were analyzed: respiratory disturbance index (RDI) in disordered breathing events/hour, periodic limb movement arousal index (PLMAI), arousals for no apparent reason (AFNAR), total arousal index (TAI), presence of REM sleep without atonia (RSWA), and percent sleep efficiency (SE).
Data on 78 patients (71M, 7F) were analyzed. The mean age was 71 ± 8 years. Seventy-five (96%) patients had histories of recurrent dream enactment during sleep with 83% showing confirmation of RSWA +/- dream enactment during PSG. Mean RDI = 11.9 ± 5.8, PLMAI = 5.9 ± 8.5, AFNARI = 10.7 ± 12.0, and TAI = 26.6 ± 17.4. SE was <80% in 72% of the sample, <70% in 49%, and <60% in 24%. In patients who did not show evidence of significant disordered breathing (23 with RDI<5), 62% of arousals were AFNARs. In those patients who had significant disordered breathing (55 with RDI ≥ 5), 36% of arousals were AFNARs. Six patients underwent evaluations with PSG plus MSLT. Two patients had mean initial sleep latencies less than five minutes, and both had RDI<5. No patient had any sleep onset rapid eye movement periods. Nineteen patients have undergone neuropathologic examination, and 18 have had limbic- or neocortical-predominant Lewy body pathology. One had progressive supranuclear palsy, but no REM sleep was recorded in prior PSG.
In patients with DLB and sleep-related complaints, several sleep disturbances in addition to RBD are frequently present. In this sample, about three quarters had a significant number of arousals not accounted for by a movement or breathing disturbance, and the primary sleep disorders do not appear to entirely account for the poor sleep efficiency in DLB, especially in those without a significant breathing disorder. Further studies are warranted to better understand the relationship between disturbed sleep, arousal and DLB; such characterization may provide insights into potential avenues of treatment of symptoms which could impact quality of life.
Sleep disorders; REM sleep behavior disorder; dementia with Lewy bodies; synucleinopathy
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
REM sleep behavior disorder; REM sleep without atonia; Parasomnia; α-synucleinopathy; Parkinsonism; Neurodegeneration; Braak staging; Melatonin; Clonazepam; Treatment; Neuropsychological testing; Neurological disease
To compare the frequency of proxy-reported REM sleep behavior disorder (RBD) among relatives of patients with polysomnogram-diagnosed idiopathic RBD (iRBD) in comparison to controls using a large multicenter clinic-based cohort.
A total of 316 patients with polysomnography-confirmed iRBD were recruited from 12 RBD study group centers, along with 316 controls matched on sex and age group. All subjects completed a self-administered questionnaire that collected proxy-reported information on family history of tremor, gait trouble, balance trouble, Parkinson disease, memory loss, and Alzheimer disease. The questionnaire also included a single question that asked about possible symptoms of RBD among first-degree relatives (siblings, parents, and children).
A positive family history of dream enactment was reported in 13.8% of iRBD cases compared to 4.8% of controls (odds ratio [OR] = 3.9, 95% confidence interval [CI] 2.0–7.7). ORs were increased for both siblings (OR = 6.1, 95% CI 2.1–18.1) and parents (OR = 3.2, 95% CI 1.4–7.8). We found no significant difference in sex, current age (65.3 ± 10.2 vs 66.9 ± 10.2 years), or age at self-reported RBD onset (55.2 ± 11.7 vs 56.6 ± 15.1 years) in possible familial vs sporadic iRBD. No differences were found in family history of tremor, walking and balance troubles, Parkinson disease, memory loss, or Alzheimer disease.
We found increased odds of proxy-reported family history of presumed RBD among individuals with confirmed iRBD. This suggests the possibility of a genetic contribution to RBD.
Rapid eye movement (REM) sleep behavior disorder (RBD) is a common parasomnia in Parkinson’s disease (PD) patients. The current International Classification of Sleep Disorders (ICSD-II) requires a clinical interview combined with video polysomnography (video-PSG) to diagnose. The latter is time consuming and expensive and not always feasible in clinical practice. Here we studied the use of actigraphy as a diagnostic tool for RBD in PD patients.
We studied 45 consecutive PD patients (66.7% men) with and without complaints of RBD. All patients underwent one night of video-PSG and eight consecutive nights of actigraphy. Based on previous studies, the main outcome measure was the total number of bouts classified as “wake”, compared between patients with (PD + RBD) and without RBD (PD- RBD).
23 (51.1%) patients had RBD according to the ICSD-II criteria. The total number of wake bouts was significantly higher in RBD patients (PD + RBD 73.2 ± 40.2 vs. PD-RBD 48.4 ± 23.3, p = .016). A cut off of 95 wake bouts per night resulted in a specificity of 95.5%, a sensitivity of 20.1% and a positive predictive value of 85.7%. Seven patients were suspected of RBD based on the interview alone, but not confirmed on PSG; six of whom scored below 95 wake bouts per night on actigraphy.
PD patients with RBD showed a significantly higher number of bouts scored as “wake” using actigraphy, compared to patients without RBD. In clinical practice, actigraphy has a high specificity, but low sensitivity in the diagnosis of RBD. The combination of actigraphy and previously reported RBD questionnaires may be a promising method to diagnose RBD in patients with PD.
Parkinson’s disease; Actigraphy; REM sleep behavior disorder; Polysomnography
Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disturbance in which patients enact their dreams while in REM sleep. The behavior is typically violent in association with violent dream content, so serious harm can be done to the patient or the bed partner. The prevalence of RBD is well-known in Parkinson’s disease, Lewy body dementia, and multiple systems atrophy. However, its prevalence and causes in stroke remained unclear. The aim of this study was to determine factors influencing the appearance of RBD in a prospective cohort of patients with acute ischemic stroke.
A total of 2,024 patients with first-ever or recurrent acute ischemic stroke were admitted to the Acute Stroke Unit at the Prince of Wales Hospital between January 2010 and November 2011; 775 of them received an MRI scan. Within 2 days of admission, a research nurse collected demographic and clinical data and assessed the severity of each stroke using the National Institute of Health Stroke Scale (NIHSS). One hundred and nineteen of the 775 patients meeting study entry criteria formed the study sample. All eligible participants were invited to attend a research clinic 3 months after the onset of the index stroke. In the attendance, a research assistant administered the MMSE and the 13-item RBD questionnaire (RBDQ).
Among 119 stroke patients, 10.9% were exhibited RBD, defined as an REM sleep behavior disorder questionnaire score of 19 or above. The proportion of patients with acute brainstem infarct was significantly higher in RBD patients than those without RBD. Compared with patients without RBD, RBD patients were more likely to have brainstem infarcts and had smaller infarct volumes. In a multivariate analysis, in which stroke location and infarct volume were inserted, brainstem infarcts were an independent predictor of RBD (odds ratio = 3.686; P = 0.032).
The results support the notion of a predominant role of brainstem injury in the development of RBD and suggest that patients with brainstem infarcts RBD should be evaluated by a clinical neurologist.
Sleep; Acute ischemic stroke; Ischemia; Brainstem; Infarcts
Increasing evidence provides a clear association between rapid eye movement sleep behavior disorders (RBD) and Parkinson’s disease (PD), but the clinical features that determine the co-morbidity of RBD and PD are not yet fully understood.
We evaluated the characteristics of nocturnal disturbances and other motor and non-motor features related to RBD in patients with PD and the impact of RBD on their quality of life. Probable RBD (pRBD) was evaluated using the Japanese version of the RBD screening questionnaire (RBDSQ-J).
A significantly higher frequency of pRBD was observed in PD patients than in the controls (RBDSQ-J ≥ 5 or ≥ 6: 29.0% vs. 8.6%; 17.2% vs. 2.2%, respectively). After excluding restless legs syndrome and snorers in the PD patients, the pRBD group (RBDSQ-J≥5) showed higher scores compared with the non-pRBD group on the Parkinson’s disease sleep scale-2 (PDSS-2) total and three-domain scores. Early morning dystonia was more frequent in the pRBD group. The Parkinson’s Disease Questionnaire (PDQ-39) domain scores for cognition and emotional well-being were higher in the patients with pRBD than in the patients without pRBD. There were no differences between these two groups with respect to the clinical subtype, disease severity or motor function. When using a cut-off of RBDSQ-J = 6, a similar trend was observed for the PDSS-2 and PDQ-39 scores. Patients with PD and pRBD had frequent sleep onset insomnia, distressing dreams and hallucinations. The stepwise linear regression analysis showed that the PDSS-2 domain “motor symptoms at night”, particularly the PDSS sub-item 6 “distressing dreams”, was the only predictor of RBDSQ-J in PD.
Our results indicate a significant impact of RBD co-morbidity on night-time disturbances and quality of life in PD, particularly on cognition and emotional well-being. RBDSQ may be a useful tool for not only screening RBD in PD patients but also predicting diffuse and complex clinical PD phenotypes associated with RBD, cognitive impairment and hallucinations.
Parkinson’s disease; Rapid eye movement sleep behavior disorder; Cognition; Quality of life; Nocturnal problems
Rapid eye movement sleep behavior disorder (RBD) is common in Parkinson disease (PD), but its relationship to the varied neurotransmitter deficits of PD and prognostic significance remain incompletely understood. RBD and cholinergic system degeneration are identified independently as risk factors for cognitive impairment in PD. We aimed to assess the association between cholinergic denervation and symptoms of RBD in PD patients without dementia.
Eighty subjects with PD without dementia (age, 64.6 ± 7.0 years; range, 50–82 years; 60 males, 20 females; mean Montreal Cognitive Assessment Test [MoCA] score, 26.2 ± 2.1; range 21–30) underwent clinical assessment, neuropsychological testing, and [11C]methylpiperidyl propionate acetylcholinesterase and [11C]dihydrotetrabenazine (DTBZ) vesicular monoamine transporter type 2 positron emission tomography (PET) imaging. 11C3-Amino-4-(2-dimethylaminomethyl-phenylsulfaryl)-benzonitrile (DASB) serotonin transporter PET imaging was performed in a subset of 35 subjects. The presence of RBD symptoms was determined using the Mayo Sleep Questionnaire.
Twenty-seven of 80 subjects (33.8%) indicated a history of RBD symptoms. Subjects with and without RBD symptoms showed no significant differences in age, motor disease duration, MoCA, Unified Parkinson Disease Rating Scale motor scores, or striatal DTBZ binding. Subjects with RBD symptoms, in comparison to those without, exhibited decreased neocortical, limbic cortical, and thalamic cholinergic innervation (0.0213 ± 0.0018 vs 0.0236 ± 0.0022, t = 4.55, p < 0.0001; 0.0388 ± 0.0029 vs 0.0423 ± 0.0058, t = 2.85, p = 0.0056; 0.0388 ± 0.0025 vs 0.0427 ± 0.0042, t = 4.49, p < 0.0001, respectively). Brainstem and striatal DASB binding showed no significant differences between groups.
The presence of RBD symptoms in PD is associated with relative neocortical, limbic cortical, and thalamic cholinergic denervation although not with differential serotoninergic or nigrostriatal dopaminergic denervation. The presence of RBD symptoms may signal cholinergic system degeneration.
Idiopathic REM sleep behavior disorder (RBD) is a parasomnia that is an important risk factor for PD and Lewy body dementia. Its prevalence is unknown. One barrier to determining prevalence is that current screening tools are too long for large-scale epidemiologic surveys. Therefore, we designed the REM Sleep Behavior Disorder Single-Question Screen (RBD1Q), a screening question for dream enactment with a simple yes/no response.
Four hundred and eighty-four sleep-clinic– based participants (242 idiopathic RBD patients and 242 controls) completed the screen during a multicenter case-control study. All participants underwent a polysomnogram to define gold-standard diagnosis according to standard criteria.
We found a sensitivity of 93.8% and a specificity of 87.2%. Sensitivity and specificity were similar in healthy volunteers, compared to controls or patients, with other sleep diagnoses.
A single-question screen for RBD may reliably detect disease, with psychometric properties favorably comparable to those reported for longer questionnaires.
REM sleep behavior disorder; screening; diagnosis
Idiopathic REM sleep behavior disorder (RBD) may be the initial manifestation of synucleinopathies (Parkinson disease [PD], multiple system atrophy [MSA], or dementia with Lewy bodies [DLB]).
We used the Mayo medical records linkage system to identify cases presenting from 2002 to 2006 meeting the criteria of idiopathic RBD at onset, plus at least 15 years between RBD and development of other neurodegenerative symptoms. All patients underwent evaluations by specialists in sleep medicine to confirm RBD, and behavioral neurology or movement disorders to confirm the subsequent neurodegenerative syndrome.
Clinical criteria were met by 27 patients who experienced isolated RBD for at least 15 years before evolving into PD, PD dementia (PDD), DLB, or MSA. The interval between RBD and subsequent neurologic syndrome ranged up to 50 years, with the median interval 25 years. At initial presentation, primary motor symptoms occurred in 13 patients: 9 with PD, 3 with PD and mild cognitive impairment (MCI), and 1 with PDD. Primary cognitive symptoms occurred in 13 patients: 10 with probable DLB and 3 with MCI. One patient presented with primary autonomic symptoms, diagnosed as MSA. At most recent follow-up, 63% of patients progressed to develop dementia (PDD or DLB). Concomitant autonomic dysfunction was confirmed in 74% of all patients.
These cases illustrate that the α-synuclein pathogenic process may start decades before the first symptoms of PD, DLB, or MSA. A long-duration preclinical phase has important implications for epidemiologic studies and future interventions designed to slow or halt the neurodegenerative process.
= dementia with Lewy bodies;
= mild cognitive impairment;
= multiple system atrophy;
= Parkinson disease;
= PD with associated mild cognitive impairment;
= Parkinson disease dementia;
= REM sleep behavior disorder.
Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by excessive muscle activity and undesirable motor events during REM sleep. RBD occurs in approximately 0.5% of the general population, with a higher prevalence in older men. RBD is a frequent feature of dementia with Lewy bodies (DLB), but is only rarely reported in Alzheimer’s disease. RBD is also a risk factor for α-synuclein-related diseases, such as DLB, Parkinson’s disease (PD), and multiple system atrophy. Therefore, RBD has major implications for the diagnosis and treatment of neurodegenerative disorders and for understanding specific neurodegeneration patterns. Several markers of neurodegeneration have been identified in RBD, including cognitive impairments such as deficits in attention, executive functions, learning capacities, and visuospatial abilities. Approximately 50% of RBD patients present mild cognitive impairment. Moreover, RBD is also associated with cognitive decline in PD.
sleep; cognition; elderly; REM sleep behavior disorder; mild cognitive impairment; Parkinson’s disease; dementia with Lewy bodies
REM sleep behavior disorder (RBD) is usually characterized by
potentially injurious dream enactment behaviors (DEB). RBD treatment aims to
reduce DEBs and prevent injury, but outcomes require further elucidation. We
surveyed RBD patients to describe longitudinal treatment outcomes with
melatonin and clonazepam.
We surveyed and reviewed records of consecutive RBD patients seen at
Mayo Clinic between 2008–2010 to describe RBD-related injury
frequency/severity as well as RBD Visual Analog Scale (VAS) ratings,
medication dosage, and side effects. Statistical analyses were performed
with appropriate non-parametric matched pairs tests before and after
treatment, and with comparative group analyses for continuous and
categorical variables between treatment groups. The primary outcome
variables were RBD VAS ratings and injury frequency.
Forty-five (84.9%) of 53 respondent surveys were analyzed.
Mean age was 65.8 years and 35 (77.8%) patients were men.
Neurodegenerative disorders were seen in 24 (53%) patients, and 25
(56%) received antidepressants. Twenty-five patients received
melatonin, 18 received clonazepam, and 2 received both as initial treatment.
Before treatment, 27 patients (60%) reported an RBD associated
injury. Median dosages were melatonin 6 mg and clonazepam 0.5 mg. RBD VAS
ratings were significantly improved following both treatments
Melatonin-treated patients reported significantly reduced injuries
(pm=.001, pc=.06) and fewer
adverse effects (p=0.07). Mean durations of treatment were no
different between groups (for clonazepam 53.9 +/− 29.5
months, and for melatonin 27.4 +/− 24 months,
p=0.13) and there were no differences in treatment retention, with
28% of melatonin and 22% of clonazepam-treated patients
discontinuing treatment (p=0.43).
Melatonin and clonazepam were each reported to reduce RBD behaviors
and injuries and appeared comparably effective in our naturalistic practice
experience. Melatonin-treated patients reported less frequent adverse
effects than those treated with clonazepam. More effective treatments that
would eliminate injury potential and evidence-based treatment outcomes from
prospective clinical trials for RBD are needed.
REM sleep behavior disorder; parasomnia; melatonin; clonazepam; treatment; side effects; tolerability; retention; injury; falls; synucleinopathy
Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia manifested by vivid, often frightening dreams associated with simple or complex motor behavior during REM sleep. Patients appear to “act out their dreams,” in which the exhibited behaviors mirror the content of the dreams, and the dream content often involves a chasing or attacking theme. The polysomnographic features of RBD include increased electromyographic tone +/- dream enactment behavior during REM sleep. Management with counseling and pharmacologic measures is usually straight-forward and effective.
In this review, the terminology, clinical and polysomnographic features, demographic and epidemiologic features, diagnostic criteria, differential diagnosis, and management strategies are discussed. Recent data on the suspected pathophysiologic mechanisms of RBD are also reviewed. The literature and our institutional experience on RBD are next discussed, with an emphasis on the RBD-neurodegenerative disease association and particularly the RBD-synucleinopathy association. Several issues relating to evolving concepts, controversies, and future directions are then reviewed, with an emphasis on idiopathic RBD representing an early feature of a neurodegenerative disease and particularly an evolving synucleinopathy. Planning for future therapies that impact patients with idiopathic RBD is reviewed in detail.
REM sleep behavior disorder; parasomnia; synucleinopathy; neurodegenerative disease
Concomitant REM sleep behaviour disorder (RBD) is commonly observed in patients with Parkinson's disease (PD). Although the brainstem structures responsible for the symptoms of RBD correspond to the premotor stages of PD, the association of RBD with motor and non-motor features in early PD remains unclear.
The study evaluated 475 patients with PD within 3.5 years of diagnosis for the presence of probable RBD (pRBD) using the REM Sleep Behaviour Disorder Screening Questionnaire (RBDSQ). A neurologist and a trained research nurse carried out evaluation of each participant blinded to the results of the RBDSQ. Standardised rating scales for motor and non-motor features of PD, as well as health-related quality of life measures, were assessed. Multiple linear and logistic regression analyses were used to determine the relationship between pRBD and a variety of outcomes, controlling for confounding factors.
The overall frequency of pRBD was 47.2% (95% CI 42.7% to 51.9%). None of the patients had a previous diagnosis of RBD. Patients with PD and concomitant pRBD did not differ on motor phenotype and scored comparably on the objective motor scales, but reported problems with motor aspects of daily living more frequently. Adjusted for age, sex, disease duration and smoking history, pRBD was associated with greater sleepiness (p=0.001), depression (p=0.001) and cognitive impairment (p=0.006).
pRBD is common and under-recognised in early PD. It is associated with increased severity and frequency of non-motor features, poorer subjective motor performance and a greater impact on health-related quality of life.
PARKINSON'S DISEASE; SLEEP DISORDERS; QUALITY OF LIFE
To determine if sleep talkers with REM sleep behavior disorder (RBD) would utter during REM sleep sentences learned before sleep, and to evaluate their verbal memory consolidation during sleep.
Eighteen patients with RBD and 10 controls performed two verbal memory tasks (16 words from the Free and Cued Selective Reminding Test and a 220-263 word long modified Story Recall Test) in the evening, followed by nocturnal video-polysomnography and morning recall (night-time consolidation). In 9 patients with RBD, daytime consolidation (morning learning/recall, evening recall) was also evaluated with the modified Story Recall Test in a cross-over order. Two RBD patients with dementia were studied separately. Sleep talking was recorded using video-polysomnography, and the utterances were compared to the studied texts by two external judges.
Sleep-related verbal memory consolidation was maintained in patients with RBD (+24±36% words) as in controls (+9±18%, p=0.3). The two demented patients with RBD also exhibited excellent nighttime consolidation. The post-sleep performance was unrelated to the sleep measures (including continuity, stages, fragmentation and apnea-hypopnea index). Daytime consolidation (-9±19%) was worse than night-time consolidation (+29±45%, p=0.03) in the subgroup of 9 patients with RBD. Eleven patients with RBD spoke during REM sleep and pronounced a median of 20 words, which represented 0.0003% of sleep with spoken language. A single patient uttered a sentence that was judged to be semantically (but not literally) related to the text learned before sleep.
Verbal declarative memory normally consolidates during sleep in patients with RBD. The incorporation of learned material within REM sleep-associated sleep talking in one patient (unbeknownst to himself) at the semantic level suggests a replay at a highly cognitive creative level.
Parasomnias are abnormal behaviors emanating from or associated with sleep. Sleepwalking and related disorders result from an incomplete dissociation of wakefulness from nonrapid eye movement (NREM) sleep. Conditions that provoke repeated cortical arousals, or promote sleep inertia lead to NREM parasomnias by impairing normal arousal mechanisms. Changes in the cyclic alternating pattern, a biomarker of arousal instability in NREM sleep, are noted in sleepwalking disorders. Sleep-related eating disorder (SRED) is characterized by a disruption of the nocturnal fast with episodes of feeding after an arousal from sleep. SRED is often associated with the use of sedative-hypnotic medications; in particular, the widely prescribed benzodiazepine receptor agonists. Recently, compelling evidence suggests that nocturnal eating may in some cases be a nonmotor manifestation of Restless Legs Syndrome (RLS). rapid eye movement (REM) Sleep Behavior Disorder (RBD) is characterized by a loss of REM paralysis leading to potentially injurious dream enactment. The loss of atonia in RBD often predates the development of Parkinson’s disease and other disorders of synuclein pathology. Parasomnia behaviors are related to an activation (in NREM parasomnias) or a disinhibition (in RBD) of central pattern generators (CPGs). Initial management should focus on decreasing the potential for sleep-related injury followed by treating comorbid sleep disorders. Clonazepam and melatonin appear to be effective therapies in RBD, whereas paroxetine has been reported effective in some cases of sleep terrors. At this point, pharmacotherapy for other parasomnias is less certain, and further investigations are necessary.
Electronic supplementary material
The online version of this article (doi:10.1007/s13311-012-0143-8) contains supplementary material, which is available to authorized users.
Parasomnia; Sleepwalking; Sleep terrors; REM sleep behavior disorder; Restless legs syndrome
The authors hypothesized that if locomotor drive increases along with rapid eye movement (REM) sleep without atonia in idiopathic REM sleep behavior disorder (RBD), then RBD patients would have greater corticomuscular coherence (CMC) values during REM sleep than at other sleep stages and than in healthy control subjects during REM sleep. To explore this hypothesis, we analyzed beta frequency range CMC between sensorimotor cortex electroencephalography (EEG) and chin/limb muscle EMG in idiopathic RBD patients. Eleven drug naive idiopathic RBD patients and 11 age-matched healthy control subjects were included in the present study. All participants completed subjective sleep questionnaires and underwent polysomnography for one night. The CMC value between EEGs recorded at central electrodes and EMGs acquired at leg and chin muscles were computed and compared by repeated measures analysis of variance (ANOVA). Sleep stages and muscle (i.e., chin vs. leg) served as within-subject factors, and group served as the between-subject factor. Repeated measures ANOVA revealed no significant main effect of group (F1,20 = 0.571, p = 0.458) or muscle (F1,20 = 1.283, p = 0.271). However, sleep stage was found to have a significant main effect (F2.067,41.332 = 20.912, p < 0.001). The interaction between group and sleep stage was significant (F2.067,41.332 = 3.438, p = 0.040). RBD patients had a significantly higher CMC value than controls during REM sleep (0.047 ± 0.00 vs. 0.052 ± 0.00, respectively, p = 0.007). This study reveals increased CMC during REM sleep in patients with RBD, which indicates increased cortical locomotor drive. Furthermore, this study supports the hypothesis that sufficient locomotor drive plays a role in the pathophysiology of RBD in addition to REM sleep without atonia.
REM sleep behavior disorder; pathophysiology; corticomuscular coherence; REM sleep without atonia
To determine whether the Parkinson disease–related covariance pattern (PDRP) expression is abnormally increased in idiopathic REM sleep behavior disorder (RBD) and whether increased baseline activity is associated with greater individual risk of subsequent phenoconversion.
For this cohort study, we recruited 2 groups of RBD and control subjects. Cohort 1 comprised 10 subjects with RBD (63.5 ± 9.4 years old) and 10 healthy volunteers (62.7 ± 8.6 years old) who underwent resting-state metabolic brain imaging with 18F-fluorodeoxyglucose PET. Cohort 2 comprised 17 subjects with RBD (68.9 ± 4.8 years old) and 17 healthy volunteers (66.6 ± 6.0 years old) who underwent resting brain perfusion imaging with ethylcysteinate dimer SPECT. The latter group was followed clinically for 4.6 ± 2.5 years by investigators blinded to the imaging results. PDRP expression was measured in both RBD groups and compared with corresponding control values.
PDRP expression was elevated in both groups of subjects with RBD (cohort 1: p < 0.04; cohort 2: p < 0.005). Of the 17 subjects with long-term follow-up, 8 were diagnosed with Parkinson disease or dementia with Lewy bodies; the others did not phenoconvert. For individual subjects with RBD, final phenoconversion status was predicted using a logistical regression model based on PDRP expression and subject age at the time of imaging (r2 = 0.64, p < 0.0001).
Latent network abnormalities in subjects with idiopathic RBD are associated with a greater likelihood of subsequent phenoconversion to a progressive neurodegenerative syndrome.
To determine structural MRI and digital microscopic characteristics of REM sleep behavior disorder in individuals with low-, intermediate-, and high-likelihood dementia with Lewy bodies (DLB) at autopsy.
Patients with autopsy-confirmed low-, intermediate-, and high-likelihood DLB, according to the probability statement recommended by the third report of the DLB Consortium, and antemortem MRI, were identified (n = 75). The clinical history was assessed for presence (n = 35) and absence (n = 40) of probable REM sleep behavior disorder (pRBD), and patients' antemortem MRIs were compared using voxel-based morphometry. Pathologic burdens of phospho-tau, β-amyloid, and α-synuclein were measured in regions associated with early neuropathologic involvement, the hippocampus and amygdala.
pRBD was present in 21 patients (60%) with high-likelihood, 12 patients (34%) with intermediate-likelihood, and 2 patients (6%) with low-likelihood DLB. Patients with pRBD were younger, more likely to be male (p ≤ 0.001), and had a more frequent neuropathologic diagnosis of diffuse (neocortical) Lewy body disease. In the hippocampus and amygdala, phospho-tau and β-amyloid burden were lower in patients with pRBD compared with those without pRBD (p < 0.01). α-Synuclein burden did not differ in the hippocampus, but trended in the amygdala. Patients without pRBD had greater atrophy of temporoparietal cortices, hippocampus, and amygdala (p < 0.001) than those with pRBD; atrophy of the hippocampus (p = 0.005) and amygdala (p = 0.02) were associated with greater phospho-tau burdens in these regions.
Presence of pRBD is associated with a higher likelihood of DLB and less severe Alzheimer-related pathology in the medial temporal lobes, whereas absence of pRBD is characterized by Alzheimer-like atrophy patterns on MRI and increased phospho-tau burden.
Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by loss of normal atonia during REM sleep, such that patients appear to act out their dreams. The most important implication of research into this area is that patients with idiopathic RBD are at very high risk of developing synuclein-mediated neurodegenerative disease (Parkinson's disease [PD], dementia with Lewy bodies [DLB], and multiple system atrophy), with risk estimates that approximate 40–65% at 10 years. Thus, RBD disorder is a very strong feature of prodromal synucleinopathy. This provides several opportunities for future research. First, patients with REM sleep behavior disorder can be studied to test other predictors of disease, which could potentially be applied to the general population. These studies have demonstrated that olfactory loss, decreased color vision, slowing on quantitative motor testing, and abnormal substantia nigra neuroimaging findings can predict clinical synucleinopathy. Second, prospectively studying patients with RBD allows a completely unprecedented opportunity to directly evaluate patients as they transition into clinical neurodegenerative disease. Studies assessing progression of markers of neurodegeneration in prodromal PD are beginning to appear. Third, RBD are very promising subjects for neuroprotective therapy trials because they have a high risk of disease conversion with a sufficiently long latency, which provides an opportunity for early intervention. As RBD research expands, collaboration between centers will become increasingly essential.
REM Sleep Behavior Disorder; Parkinson's disease; Dementia with Lewy bodies; prodromal
Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disorder that predominantly affects older adults, in which patients appear to be enacting their dreams while in REM sleep. The behaviors are typically violent, in association with violent dream content, so serious harm can be done to the patient or the bed-partner. The estimated prevalence in adults is 0.4–0.5%, but the frequency is much higher in certain neurodegenerative diseases, especially Parkinson's disease, Dementia with Lewy bodies, and multiple systems atrophy. RBD can occur in the absence of diagnosed neurologic diseases (the “idiopathic” form), although patients with this form of RBD may have subtle neurologic abnormalities and often ultimately develop a neurodegenerative disorder. Animal models and cases of RBD developing after brainstem lesions (pontine tegmentum, medulla) have led to the understanding that RBD is caused by a lack of normal REM muscle atonia and a lack of normal suppression of locomotor generators during REM. Clonazepam is used as first-line therapy for RBD and melatonin for second-line therapy, although evidence for both of these interventions comes from uncontrolled case series. Because the risk of injury to the patient or the bed-partner is high, interventions to improve the safety of the sleep environment are also often necessary. This review describes the epidemiology, pathophysiology, and treatment of RBD.
Compare the frequency of REM sleep behavior disorder (RBD) and excessive daytime sleepiness (EDS) in Parkinson’s disease (PD), restless legs syndrome (RLS), essential tremor (ET), and control subjects.
Subjects enrolled in a longitudinal clinicopathologic study, and when available an informant, completed the Mayo Sleep Questionnaire, which asks “Have you ever been told that you act out your dreams?”, and the Epworth Sleepiness Scale (ESS).
Probable RBD (based on informant response to the questionnaire) was much more frequent in PD (34/49, 69%, p<0.001) than in RLS (6/30, 20%), ET (7/53, 13%), or control subjects (23/175, 13%), with an odds ratio of 11 for PD compared to controls. The mean ESS and the number of subjects with an ESS ≥ 10 was higher in PD (29/60, 48%, p<0.001) and RLS (12/39, 31%, p<0.001) compared with ET (12/93, 13%) and Controls (34/296, 11%).
Probable RBD is much more frequent in PD with no evidence to suggest an increase in either RLS or ET. Given the evidence that RBD is a synucleinopathy, the lack of an increased frequency of RBD in subjects with ET or RLS suggests the majority of ET and RLS subjects are unlikely to be at increased risk for developing PD.
Parkinson’s disease; REM sleep behavior disorder; essential tremor; restless legs syndrome; excessive daytime sleepiness
Over 50% of persons with idiopathic REM sleep behavior disorder (RBD) will develop Parkinson disease (PD) or dementia. At present, there is no way to predict who will develop disease. Since polysomnography is performed in all patients with idiopathic RBD at diagnosis, there is an opportunity to analyze if baseline sleep variables predict eventual neurodegenerative disease.
In a longitudinally studied cohort of patients with idiopathic RBD, we identified those who had developed neurodegenerative disease. These patients were matched by age, sex, and follow-up duration to patients with RBD who remained disease-free and to controls. Polysomnographic variables at baseline (i.e., before development of neurodegenerative disease) were compared between groups.
Twenty-six patients who developed neurodegenerative disease were included (PD 12, multiple system atrophy 1, dementia 13). The interval between polysomnogram and disease onset was 6.7 years, mean age was 69.5, and 81% were male. There were no differences between groups in sleep latency, sleep time, % stages 2–4, % REM sleep, or sleep efficiency. However, patients with idiopathic RBD who developed neurodegenerative disease had increased tonic chin EMG activity during REM sleep at baseline compared to those who remained disease-free (62.7 ± 6.0% vs 41.0 ± 6.0%, p = 0.020). This effect was seen only in patients who developed PD (72.9 ± 6.0% vs 41.0 ± 6.0%, p = 0.002), and not in those who developed dementia (54.3 ± 10.3, p = 0.28). There was no difference in phasic submental REM EMG activity between groups.
In patients with REM sleep behavior disorder initially free of neurodegenerative disease, the severity of REM atonia loss on baseline polysomnogram predicts the development of Parkinson disease.
= Diagnostic and Statistical Manual of Mental Disorders, 4th edition;
= Parkinson disease;
= REM sleep behavior disorder.