Disclosing the Risk Associated with Isolated REM Behavior Disorder: The Sleep Experts' Perspective.

BACKGROUND: Isolated rapid-eye-movement sleep behavior disorder (iRBD) is associated with a high risk for phenoconversion to a neurodegenerative disorder, but the optimal approach for disclosure of this risk to patients is still debated. OBJECTIVES: The aim of this study was to explore views and experiences of iRBD experts regarding risk disclosure. METHODS: In this qualitative study, semi-structured interviews with sleep experts caring for patients with iRBD were analyzed through a conventional content analysis approach. RESULTS: We interviewed 22 iRBD experts (eight female, average age of 51.8 years) from 18 Italian sleep centers; 21/22 regularly disclosed the risks associated with iRBD, usually after the video-polysomnography, and 8/22 regularly mentioned phenoconversion rates. Content analysis allowed us to identify three main themes. First, sleep experts reported several points in favor of risk disclosure, especially related to the principle of beneficence, but some highlighted the need for specific learning on the topic. Second, experts favored a patient-tailored disclosure that should not upset the patient unnecessarily, since phenoconversion is uncertain. Third, risk disclosure was seen by participants as a relational task that should be carried out in person in the context of a trusting patient-physician relationship, while they had contrasting views regarding patients' previous knowledge. CONCLUSIONS: Sleep experts generally preferred a tailored and reassuring approach to risk disclosure within a framework of relational autonomy. The results of this study indicate the need for specific education, training, and recommendations concerning risk disclosure that should also include patients' and families' preferences.

Reading the mind in the eyes in patients with idiopathic REM sleep behavior disorder.

OBJECTIVES: Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is characterized by vocalizations, jerks, and motor behaviors during REM sleep, often associated with REM-related dream content, which is considered a prodromal stage of α-synucleinopathy. The results of the Reading the Mind in the Eyes (RME) reflecting affective Theory of Mind (ToM) are inconsistent in α-synucleinopathy. The present study tried to investigate the RME in patients with iRBD. METHODS: A total of 35 patients with iRBD and 26 healthy controls were included in the study. All participants were administered the RME and the cognitive assessments according to a standard procedure. The patients with iRBD were further divided into two groups (high or low RME) according to the scores of the RME (> 21, or ≤ 20). RESULTS: The patients with iRBD had worse scores on cognitive tests compared with healthy controls involving global cognitive screening, memory, and visuospatial abilities (p < 0.05), but the scores of the RME were similar between the two groups (20.83 ± 3.38, 20.58 ± 3.43) (p ˃ 0.05). Patients with low RME had more obvious cognitive impairments than healthy controls. After applying Bonferroni correction for multiple tests, the low REM group only performed worse on the Sum of trials 1 to 5 and delayed recall of the RAVLT compared with the healthy control group (p < 0.001, = 0.002). The RME correlated with the scores of cognitive tests involving executive function, attention, memory, and visuospatial function. CONCLUSIONS: The changes in RME had a relationship with cognitive impairments, especially memory, in patients with iRBD.

Neuropsychological Changes in Isolated REM Sleep Behavior Disorder: A Systematic Review and Meta-analysis of Cross-sectional and Longitudinal Studies.

The aim of this meta-analysis is twofold: (a) to assess cognitive impairments in isolated rapid eye movement (REM) sleep behavior disorder (iRBD) patients compared to healthy controls (HC); (b) to quantitatively estimate the risk of developing a neurodegenerative disease in iRBD patients according to baseline cognitive assessment. To address the first aim, cross-sectional studies including polysomnography-confirmed iRBD patients, HC, and reporting neuropsychological testing were included. To address the second aim, longitudinal studies including polysomnography-confirmed iRBD patients, reporting baseline neuropsychological testing for converted and still isolated patients separately were included. The literature search was conducted based on PRISMA guidelines and the protocol was registered at PROSPERO (CRD42021253427). Cross-sectional and longitudinal studies were searched from PubMed, Web of Science, Scopus, and Embase databases. Publication bias and statistical heterogeneity were assessed respectively by funnel plot asymmetry and using I2. Finally, a random-effect model was performed to pool the included studies. 75 cross-sectional (2,398 HC and 2,460 iRBD patients) and 11 longitudinal (495 iRBD patients) studies were selected. Cross-sectional studies showed that iRBD patients performed significantly worse in cognitive screening scores (random-effects (RE) model = -0.69), memory (RE model = -0.64), and executive function (RE model = -0.50) domains compared to HC. The survival analyses conducted for longitudinal studies revealed that lower executive function and language performance, as well as the presence of mild cognitive impairment (MCI), at baseline were associated with an increased risk of conversion at follow-up. Our study underlines the importance of a comprehensive neuropsychological assessment in the context of iRBD.

Progression of brain cholinergic dysfunction in patients with isolated rapid eye movement sleep behavior disorder.

BACKGROUND: Reduced cortical acetylcholinesterase activity, as measured by 11 C-donepezil positron emission tomography (PET), has been reported in patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD). However, its progression and clinical implications have not been fully investigated. Here, we explored the relationship between longitudinal changes in brain acetylcholinesterase activity and cognitive function in iRBD. METHODS: Twelve iRBD patients underwent 11 C-donepezil PET at baseline and after 3 years. PET images were interrogated with statistical parametric mapping (SPM) and a regions of interest (ROI) approach. Clinical progression was assessed with the Movement Disorder Society-Unified Parkinson's Disease Rating Scale-Part III (MDS-UPDRS-III). Cognitive function was rated using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). RESULTS: From baseline to follow-up, the mean 11 C-donepezil distribution volume ratio (DVR) decreased in the cortex (p = 0.006), thalamus (p = 0.013), and caudate (p = 0.013) ROI. Despite no significant changes in the group mean MMSE or MoCA scores being observed, individually, seven patients showed a decline in their scores on these cognitive tests. Subgroup analysis showed that only the subgroup of patients with a decline in cognitive scores had a significant reduction in mean cortical 11 C-donepezil DVR. CONCLUSIONS: Our results show that severity of brain cholinergic dysfunction in iRBD patients increases significantly over 3 years, and those changes are more severe in those with a decline in cognitive test scores.

Characterization of attentional event-related potential from REM sleep behavior disorder patients based on explainable machine learning.

BACKGROUND AND OBJECTIVE: Idiopathic rapid eye movement sleep behavior disorder (iRBD) is a prodromal stage of neurodegeneration and is associated with cortical dysfunction. The purpose of this study was to investigate the spatiotemporal characteristics of cortical activities underlying impaired visuospatial attention in iRBD patients using an explainable machine-learning approach. METHODS: An algorithm based on a convolutional neural network (CNN) was devised to discriminate cortical current source activities of iRBD patients due to single-trial event-related potentials (ERPs), from those of normal controls. The ERPs from 16 iRBD patients and 19 age- and sex-matched normal controls were recorded while the subjects were performing visuospatial attentional task, and converted to two-dimensional images representing current source densities on flattened cortical surface. The CNN classifier was trained based on overall data, and then, a transfer learning approach was applied for the fine-tuning to each patient. RESULTS: The trained classifier yielded high classification accuracy. The critical features for the classification were determined by layer-wise relevance propagation, so that the spatiotemporal characteristics of cortical activities that were most relevant to cognitive impairment in iRBD were revealed. CONCLUSIONS: These results suggest that the recognized dysfunction in visuospatial attention of iRBD patients originates from neural activity impairment in relevant cortical regions and may contribute to the development of useful iRBD biomarkers based on neural activity.

Neuropsychological evaluation of phenoconversion risk in REM sleep behaviour disorder: A scoping review.

The objective of this study was to assess the role of cognitive evaluation in the prediction of phenoconversion in polysomnography-confirmed idiopathic or isolated rapid eye movement sleep behaviour disorder, through a scoping review focussing on a longitudinal comprehensive neuropsychological assessment of patients with idiopathic REM sleep behaviour disorder. A literature search (2006-2022) yielded 1034 records, and 20 were selected for analysis. The sample included 899 patients from eight different cohorts and five countries. We extracted data on clinical evolution, mild cognitive impairment diagnosis, neuropsychological tests used, and classification of cognitive domains. Tests, cognitive domains, and mild cognitive impairment definitions were heterogeneous across the studies, precluding a meta-analysis. Ten studies (50%) evaluated the presence of mild cognitive impairment; 14 studies (70%) grouped neuropsychological tests into between three (6 studies, 21.4%) and seven (1 study, 7.1%) cognitive domains. The most frequently used tests were semantic fluency, Stroop colour word test, trail making test A and B, digit span, Rey auditory verbal learning test, and Rey-Osterrieth figure. All except digit span showed a role in predicting phenoconversion. The authors did not consistently assign tests to specific cognitive domains. In conclusion, we discuss methodological differences between the studies and highlight the need for a standardised framework for neuropsychological data acquisition and presentation, based on a multilevel approach covering test selection, domain assignment, and mild cognitive impairment diagnostic criteria.

A data-driven approach to neuropsychological features in isolated REM behaviour disorder: A latent class analysis.

Recent evidence demonstrated that neuropsychological assessment may be considered a valid marker of neurodegeneration in idiopathic REM sleep behaviour disorder (iRBD). However, little is known about the possible neuropsychological heterogeneity within the iRBD population. This retrospective study aimed to identify and describe different neuropsychological phenotypes in iRBD patients by means of a data-driven approach using latent class analysis. A total of 289 iRBD patients underwent a neuropsychological assessment evaluating cognitive domains: global cognition, language, short- and long-term memory, executive functions and visuospatial abilities. The presence of mild cognitive impairment (MCI) was also assessed. Latent class analysis was carried out to identify iRBD subtypes according to neuropsychological scores. The most parsimonious model identified three latent classes. Groups were labelled as follows: Class 2 "severely impaired" (n = 83/289): mean pathological scores in different tests, a high percentage of MCI multiple-domain and impairment in all neuropsychological domains. Class 1 "moderately impaired" (n = 44/289): mean neuropsychological score within the normal value, a high percentage of MCI (high risk to phenoconversion) and great impairment in the visuospatial domain. Class 3 "slightly impaired" (n = 162/289): no deficit worthy of attention except for short- and long-term memory. Our results suggest three different clinical phenotypes within the iRBD population. These findings may be relevant in the future for predicting the clinical trajectories of phenoconversion in iRBD.

Increased blood pressure variability is associated with probable rapid eye movement sleep behaviour disorder in elderly hypertensive patients.

PURPOSE: An increased blood pressure variability (BPV) has been reported to be associated with older age and cognitive dysfunction; however, associations between increased BPV and rapid eye movement sleep behaviour disorder (RBD) has not been thoroughly investigated in patients without clinical Lewy body diseases. MATERIALS AND METHODS: In frailty outpatient clinic, we evaluated ambulatory BP, RBD screening questionnaire (RBDSQ), and beat-to-beat heart rate variability during positional change from sitting to standing in 112 elderly hypertensive patients. RESULTS: The mean age was 81.2 ± 6.3 years (68% male). There were 15 patients who had probable RBD (RBDSQ scores ≥ 5). Patients with RBD had a greater body mass index, coefficient of variation (CV) in 24-h diastolic BP (23.5 ± 6.1 versus 18.7 ± 5.8, p = 0.005), awake diastolic BP (23.0 ± 7.7 versus 18.6 ± 6.2, p = 0.017), and nocturnal systolic BP (14.9 ± 5.5 versus 12.0 ± 4.4, p = 0.025) compared with those without RBD, while systolic BP, diastolic BP, and cognitive function did not differ significantly between patients with and without RBD. Patients with RBD exhibited larger orthostatic BP fall compared with patients without RBD (-4.9 ± 11.0 versus 7.5 ± 11.8, p = 0.009) and lower CV of R-R intervals while standing (1.3 ± 0.6 versus 2.4 ± 1.5, p = 0.039). Multiple regression analysis revealed that patients with RBD had significantly greater CV of nocturnal systolic BP independent of age, sex, BMI, history of diabetes and dyslipidaemia, and use of antihypertensive drugs (p = 0.008). CONCLUSION: An increased BPV in ambulatory BP, associated with autonomic dysfunction, can be observed in patients with probable RBD even in elderly patients without clinical presentation of Lewy body diseases.

Obsessive-compulsive personality disorder in rapid eye movement sleep behavior disorder.

Rapid eye movement sleep behavior disorder (RBD) is a common prodromic non-motor symptom of Parkinson's disease (PD). Only few studies have evaluated the personality of RBD patients with conflicting results. Aim of the study was to evaluate the frequency of Personality Disorders (PeDs)in RBD. RBD patients, PD patients and healthy controls (HC) were enrolled. All the enrolled subjects underwent a full neurological examination. Motor symptoms were evaluated with the UPDRS-Motor Examination. PeDs were assessed with the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II). Twenty-nine RBD patients [14 men (48.3%); mean age 55.6 ± 11.1], 30 PD patients [17 men (56.7%); mean age 65.7 ± 10.7] and 30 HC [12 men (40%); mean age 65.7 ± 5.4] were enrolled in the study. PD patients had a disease duration of 4.5 ± 4.6 and presented a mean UPDRS-ME score of 26.7 ± 9.4. The most frequent PeDs was the Obsessive-Compulsive one (OCPeD); OCPeD was significantly more frequent in RBD (55.2%) patients than HC (13.3%; p-value < 0.001). No significant differences were found comparing the frequency of OCPeD in RBD patients to that in PD. In the present study, the prevalence of OCPeD in RBD patients was close to that reported in PD patients. Our data could suggest the existence of a common disease-specific RBD-PD personality profile.

Decision making under uncertainty in Parkinson's disease with Rem sleep behavior disorder.

BACKGROUND: REM sleep behavior disorder (RBD) is associated with an increased risk to develop Impulse control disorders (ICDs) in Parkinson's disease (PD), however the mechanisms underlying this putative association are still poorly understood. Decision-making impairment, one major neuro-psychological dimension that may lead to ICDs, has been reported in idiopathic RBD, but has never been assessed in RBD associated with PD. OBJECTIVE: We aimed to assess decision-making abilities under ambiguous situations associated with the presence of RBD in PD patients. METHODS: In this cross-sectional study, 60 non-demented PD patients with (PD-RBD, n = 40) and without (PD-nRBD, n = 20) video polysomnography-confirmed RBD, and 20 healthy controls matched for gender and age were included. All subjects underwent neurological and neuropsychological examination, including Iowa Gambling task designed to asses decision-making under uncertainty. RESULTS: IGT total score did not differ between groups (p = 0.851), however PD-RBD presented, more disadvantageous choices for the last blocks of IGT compared to PD-nRBD (p = 0.001) and to HC (p = 0.012). Progression of scores did not differ between HC and PD-nRBD. Multivariate analyses taking into account the value of scores at baseline, as well as the duration of PD, the duration of treatment, the presence of ICDs and MMSE confirmed those results. CONCLUSION: Decision making under uncertainty is impaired in PD-RBD compared to PD-nRBD and healthy controls, regardless to the duration of disease, treatment, cognitive status and the presence of ICDs. This could reflect an inability to learn from punishment or reward in PD-RBD, and could explain the increased risk to develop ICDs reported in those patients.

Apolipoprotein E ε4 is not associated with cognitive impairment in patients with idiopathic REM sleep behavior disorder.

We analyzed 136 patients (age, 67.5 ± 6.9 years; men, 59.6%) with idiopathic rapid eye movement sleep behavior disorder (iRBD). The results of the neuropsychological tests were not significantly different between APOE ε4 carriers and noncarriers, suggesting that the APOE ε4 allele was not associated with cognitive impairment in iRBD.

Mild cognitive impairment and abnormal brain metabolic expression in idiopathic REM sleep behavior disorder.

BACKGROUND: Mild cognitive impairment (MCI) is a common feature of isolated rapid-eye-movement sleep behavior disorder (iRBD). Here, we assessed cognitive functions and MCI in a prospective iRBD cohort and investigated their association with disease-specific brain metabolic patterns. METHODS: Forty-four patients with polysomnography-confirmed iRBD performed a standardized battery of neuropsychological examinations every two years. We used previously established spatial covariance patterns from de novo drug-naïve Parkinson's disease with concomitant RBD (denovoPDRBD-RP) and iRBD (iRBD-RP) using 18F-fluorodeoxyglucose PET scan. We compared those expressions between iRBD with normal cognition (iRBD-NC) and with mild cognitive impairment (iRBD-MCI), and evaluated whether they predict progressive cognitive deterioration. RESULTS: Twenty iRBD patients (45 %) had MCI at baseline and 12 patients (27 %, about 7 % per year) had clinically significant cognitive deterioration after 4 years. The iRBD-MCI and iRBD-NC groups showed similar rates of cognitive change, but iRBD-MCI consistently performed worse in the domains of verbal memory and executive function. Elevated denovoPDRBD-RP expression predicted cognitive deterioration (hazard ratio = 5.98 [1.70-21.06]), whereas iRBD-RP did not. CONCLUSIONS: Increased disease-specific brain metabolic patterns are associated with iRBD-MCI and impending cognitive deterioration with the risk of progression to Lewy body dementia.

[Dream content in different sleep disorders: sleep apnoea and hypopnoea syndrome, primary insomnia, idiopathic REM sleep behaviour disorder and narcolepsy type 1]. / Contenido onírico en diferentes trastornos del sueño: síndrome de apnea e hipopnea del sueño, insomnio primario, trastorno de la conducta del sueño REM idiopático y narcolepsia de tipo 1.

AIM: The aim of this study is to determine whether there are any differences in the dream content in different sleep disorders and to describe their characteristics. PATIENTS AND METHODS: We studied four sleep disorders: sleep apnoea and hypopnoea syndrome (SAHS), primary insomnia (PI), idiopathic REM sleep behaviour disorder (IRBD) and narcolepsy type I. Each patient was asked to keep a dream diary for two weeks. The content of the diaries was transcribed and analysed for length, mental content, complexity and threat. The results were compared to establish differences. RESULTS: Eighty-nine patients were studied: 23 with SAHS without continuous positive airway pressure (CPAP) who had the highest number of dreams involving threats (32.5%); 19 with SAHS treated with CPAP who had the highest number of dreams involving objects (64.8%), descriptive elements (38%) and higher complexity (9.5%); 22 with primary insomnia who had the highest number of dreams with threatening events in the social sphere (57.7%); 12 with IRBD who had the highest number of dreams with failures (14%) and lower complexity (71.7%); and 13 with narcolepsy type I who had the highest number of dreams related to activities (84.3%) and threats to life (41.4%) These differences were statistically significant (p <0.05). CONCLUSIONS: Different sleep disorders are associated with different dream contents, which would be translating different underlying neurological processes. These findings should be replicated in studies that analyse more patients and add a control group without sleep disorders.

TITLE: Contenido onírico en diferentes trastornos del sueño: síndrome de apnea e hipopnea del sueño, insomnio primario, trastorno de la conducta del sueño REM idiopático y narcolepsia de tipo 1.Objetivo. Determinar si existen diferencias en el contenido onírico en diferentes trastornos del sueño y describir sus características. Pacientes y métodos. Estudiamos cuatro trastornos del sueño: síndrome de apnea e hipopnea del sueño (SAHS), insomnio primario (IP), trastorno de conducta del sueño REM idiopático (TCSRI) y narcolepsia de tipo 1. Se solicitó a cada paciente que llenara un diario de sus sueños durante dos semanas. El contenido de los diarios fue transcrito y analizado en longitud, contenido mental, complejidad y amenaza. Los resultados se compararon para establecer diferencias. Resultados. Se estudió a 89 pacientes: 23 con SAHS sin presión positiva continua de la vía aérea (CPAP) que tuvieron la mayor cantidad de sueños con participación en amenazas (32,5%); 19 con SAHS tratados con CPAP que tuvieron la mayor cantidad de sueños con objetos (64,8%), elementos descriptivos (38%) y de más alta complejidad (9,5%); 22 con insomnio primario con la mayor cantidad de sueños con eventos amenazantes al ámbito social (57,7%); 12 con TCSRI que tuvieron en sus sueños la más alta cantidad de fracasos (14%) y menor complejidad (71,7%), y 13 con narcolepsia de tipo 1 que tuvieron la mayor cantidad de sueños relacionados con actividades (84,3%) y amenazas hacia la vida (41,4 %). Estas diferencias fueron estadísticamente significativas (p menor de 0,05). Conclusiones. Los distintos trastornos del sueño sí se asocian a contenidos oníricos diferentes que traducirían distintos procesos neurológicos subyacentes. Estos hallazgos deberían replicarse en estudios que analicen más pacientes y añadan un grupo control sin trastornos del sueño.

Characterization of Depressive and Anxiety Symptoms in Idiopathic REM Sleep Behavior Disorder.

BACKGROUND: Depression and anxiety are common in synucleinopathies and often present during prodromal stages, including idiopathic/isolated REM sleep behavior disorder (iRBD). However, the specific profiles of depression/anxiety and their predictive values for phenoconversion remain unclear. OBJECTIVE: To assess the predominant manifestations, predictive value, and changes over time in depressive and anxiety symptoms in iRBD. METHODS: Patients with polysomnography-confirmed iRBD (n = 114) and healthy controls (n = 44) were recruited. The Beck Depression Inventory and Beck Anxiety Inventory were administered at baseline, which was repeated prospectively over follow-up. Factor solutions were generated to delineate symptom clusters within the scales, and to help disentangle primary mood symptoms from other neurodegenerative confounds. Total scores, individual scale items, and factors were evaluated to 1) compare patients and controls, 2) assess progression of symptoms over time, and 3) assess predictive value for phenoconversion. RESULTS: At baseline, iRBD patients had more severe depressive (9.0 = 6.7 vs 5.8 = 4.8) and anxiety (7.0 = 7.9 vs 4.5 = 6.0) symptoms than controls. Increased scores were seen in numerous individual scale items and most scales' factors. For depressive symptoms, there was no progression of total scores or factors over time. However, anxiety scores worsened slightly over prospective follow-up (annual slope = 0.58 points, p < 0.05). Over an average 2.4 = 3.1-year follow-up, 37 patients phenoconverted and 72 remained disease-free. Neither baseline depressive nor anxiety symptoms predicted phenoconversion to clinical neurodegenerative disease. CONCLUSIONS: Depressive and anxiety symptoms are common in iRBD. However, they do not predict phenoconversion and show only modest progression over time, solely for anxiety.

The Effect of Self-Reported REM Behavior Disorder Symptomology on Intrusive Memories in Post-Traumatic Stress Disorder.

Background: PTSD is characterised by severe sleep disturbances, which is increasingly recognised to in many cases consist of similar symptomology to sleep disorders such as REM Behaviour Disorder (RBD). The present study aimed to investigate whether different aspects of sleep quality influence intrusive memory development and whether PTSD status moderates this relationship. Participants and Methods: 34 PTSD, 52 trauma-exposed (TE) and 42 non-trauma exposed (NTE) participants completed an emotional memory task, where they viewed 60 images (20 positive, 20 negative and 20 neutral) and, two days later, reported how many intrusive memories they had of each valence category. Participants also completed three measures of sleep quality: the Pittsburgh Sleep Quality Index, the REM Behaviour Disorder Screening Questionnaire and total hours slept before each session. Results: The PTSD group reported poorer sleep quality than both TE and NTE groups on all three measures, and significantly more negative intrusive memories than the NTE group. Mediation analyses revealed that self-reported RBD symptomology before the second session mediated the relationship between PTSD status and intrusive memories. Follow-up moderation analyses revealed that self-reported RBD symptomology before the second session was only a significant predictor of intrusion in the PTSD group, though with a small effect size. Conclusions: These findings suggest that RBD symptomology is an indicator of consolidation of intrusive memories in PTSD but not trauma-exposed or healthy participants, which supports the relevance of characterising RBD in PTSD.

Propagated α-synucleinopathy recapitulates REM sleep behaviour disorder followed by parkinsonian phenotypes in mice.

Idiopathic rapid eye movement sleep behaviour disorder (RBD) is now recognized as an early manifestation of α-synucleinopathies. Increasing experimental studies demonstrate that manipulative lesion or inactivation of the neurons within the sublaterodorsal tegmental nucleus (also known as the subcoeruleus nucleus in humans) can induce RBD-like behaviours in animals. As current RBD animal models are not established on the basis of α-synucleinopathy, they do not represent the pathological substrate of idiopathic RBD and thus cannot model the phenoconversion to Parkinson's disease. The purpose of this study was therefore to establish an α-synucleinopathy-based RBD animal model with the potential to convert to parkinsonian disorder. To this end, we first determined the functional neuroanatomical location of the sublaterodorsal tegmental nucleus in wild-type C57BL/6J mice and then validated its function by recapitulating RBD-like behaviours based on this determined nucleus. Next, we injected preformed α-synuclein fibrils into the sublaterodorsal tegmental nucleus and performed regular polysomnographic recordings and parkinsonian behavioural and histopathological studies in these mice. As a result, we recapitulated RBD-like behaviours in the mice and further showed that the α-synucleinopathy and neuron degeneration identified within the sublaterodorsal tegmental nucleus acted as the neuropathological substrates. Subsequent parkinsonian behavioural studies indicated that the α-synucleinopathy-based RBD mouse model were not stationary, but could further progress to display parkinsonian locomotor dysfunction, depression-like disorder, olfactory dysfunction and gastrointestinal dysmotility. Corresponding to that, we determined α-synuclein pathology in the substantia nigra pars compacta, olfactory bulb, enteral neuroplexus and dorsal motor nucleus of vagus nerve, which could underlie the parkinsonian manifestations in mice. In conclusion, we established a novel α-synucleinopathy-based RBD mouse model and further demonstrated the phenoconversion of RBD to Parkinson's disease in this animal model.

Prodromal Marker Progression in Idiopathic Rapid Eye Movement Sleep Behavior Disorder: Sample Size for Clinical Trials.

OBJECTIVE: To estimate prodromal marker progression in idiopathic rapid eye movement sleep behavior disorder patients with prodromal Parkinson's disease (PD) to calculate sample size for neuroprotective trials. METHODS: Patients with polysomnogram-proven idiopathic rapid eye movement sleep behavior disorder were assessed for prodromal PD using Movement Disorder Society criteria. We prospectively measured progression rates of numerous clinical variables, including motor, cognitive, special sensory, and autonomic variables and calculated the sample size required to demonstrate slowing of progression under 3 effectiveness assumptions (30%, 50%, and 70% slowing). RESULTS: Overall, the variables that progressed with lowest sample size requirements were motor variables (234 participants required per group for 50% efficacy over 2 years). By contrast, cognitive, special sensory, and autonomic variables showed modest progression with high variability, resulting in high sample sizes. The most efficient design was a time-to-event analysis using milestones of motor and cognitive decline (126 per group). CONCLUSION: In idiopathic rapid eye movement sleep behavior disorder, time-to-event analysis assessing milestones of decline is the most efficient trial design for neuroprotective therapy. © 2019 International Parkinson and Movement Disorder Society.

Physician and patient determinants of prognostic counseling in idiopathic REM sleep-behavior disorder.

OBJECTIVES/BACKGROUND: Prognostic counseling about the risk for developing overt neurodegenerative disorders for patients with idiopathic REM sleep-behavior disorder (iRBD) and isolated REM sleep without atonia (iRSWA) is difficult, given lack of disease-modifying interventions and uncertainty in accurate prognostication for individuals. We aimed to analyze patient and physician characteristics associated with documented prognostic discussions for patients with iRBD and iRSWA. PATIENTS/METHODS: We retrospectively reviewed the medical records for 138 (112 iRBD and 26 iRSWA) patients seen at the Mayo Clinic between 2012 and 2015. We analyzed physician and patient demographics, initial complaint, and other information discussed during office visits. We then comparatively analyzed the impact of physician and patient characteristics on documented prognostic discussions using Chi Square or Fischer's exact test. RESULTS: Mean iRBD patient age was 65.0 ± 13.0, and mean iRSWA age was 58 ± 15 years. Seventy-eight (69.6%) iRBD and 22 (84.6%) iRSWA patients were men. Sixty-two (55%) iRBD and three (12%) iRSWA patients received prognostic counseling about phenoconversion risk. iRBD was a secondary complaint in 67 (59.8%). Patients over age 60 years and those having iRBD as a chief complaint more frequently received prognostic discussions than those with opposite characteristics (all p < 0.05). Patient sex and antidepressant use were not associated with counseling. Sleep neurologists disclosed prognostic information most frequently, with male more likely than female clinicians to disclose prognoses. CONCLUSIONS: Several patient and physician characteristics appear to influence documented prognostic counseling for iRBD/RSWA patients. Future studies of iRBD/RSWA patients' preferences are needed to clarify ethically appropriate physician-patient communication concerning prognosis.

Impaired sleep quality and cognition in patients of Parkinson's disease with REM sleep behavior disorder: a comparative study.

OBJECTIVES: The present study was undertaken to evaluate the cognitive profile of Parkinson's disease (PD) patients with REM sleep behavior disorder (RBD) and to correlate with the clinical stage and polysomnographic variables. METHODS: The study included 25 PD patients who had RBD and 25 PD patients who based on two questionnaires were determined as not having RBD. These patients underwent overnight polysomnography (PSG) and neuropsychological assessment using a defined battery of tests. RESULTS: The mean age of the patients with clinically probable RBD (RBD+) was 60.4 ± 8.2 years and PD patients without RBD (RBD-) was 57.3 ± 6.6 years (p = 0.14). The mean age at onset of the disease was 53.7 ± 9.4 years for RBD+ and 49.8 ± 7.8 years for RBD-patients (p = 0.12). The mean Unified Parkinson Disease Rating Scale (UPDRS) part III OFF score was 27.4 ± 11.1 for RBD+ and 32.7 ± 8.2 for RBD- (p = 0.06). The total sleep time of the patients was 4.3 ± 1.7 h with sleep efficiency of 53.8 ± 21.0%. Patients with RBD+ were found to have significant impairment in many neuropsychological tests compared to RBD-. CONCLUSIONS: RBD + patients had significant impairment in MMSE, category fluency test (FAS test), frontal assessment battery, attention (digit span backwards, Corsi span), verbal memory (story recall) and Rey's auditory verbal learning test. These patients also had poor sleep quality.