[A case of left posterior cortical atrophy presenting with kana-predominant reading impairment].

The patient was an 85-year-old man with a one-year history of difficulty reading kana. Neuropsychological evaluation revealed kana (phonogram)-selective reading impairment and kanji (ideogram)-dominant writing impairment. MRI revealed significant cerebral atrophy in the left occipital cortex, leading to the clinical diagnosis of posterior cortical atrophy (PCA). Cerebrospinal fluid amyloid ß1-42 levels were reduced, and amyloid PET showed accumulation in the posterior cingulate cortex, precuneus, and frontal lobe. In contrast, tau PET showed no accumulation in the atrophied brain areas. Episodes of REM sleep behavior disorder and decreased uptake on meta-iodobenzylguanidine (MIBG) myocardial scintigraphy suggested the involvement of Lewy body pathology. PCA with distinct laterality has been rarely reported, and |this is the first case to present Kana-selective reading impairment and Kanji-dominant writing impairment with neurodegenerative background.

Developing disease-modifying interventions in idiopathic REM sleep behavior disorder and early synucleinopathy.

Alpha-synucleinopathies are prevalent neurological disorders that cause significant disability, leading to progressive clinical deterioration that is currently managed solely through symptomatic treatment. Efforts to evaluate disease-modifying therapies during the established stage of the disease have not yielded positive outcomes in terms of clinical or imaging efficacy endpoints. However, alpha-synucleinopathies have a long prodromal phase that presents a promising opportunity for intervention with disease-modifying therapies. The presence of polysomnography-confirmed REM sleep behavior disorder (RBD) is the most reliable risk factor for identifying individuals in the prodromal stage of alpha-synucleinopathy. This paper discusses the rationale behind targeting idiopathic/isolated RBD in disease-modifying trials and outlines possible study designs, including strategies for patient stratification, selection of biomarkers to assess disease progression and patient eligibility, as well as the identification of suitable endpoints. Additionally, the potential targets for disease-modifying treatment in alpha-synucleinopathies are summarized.

A Population-Based Approach to the Argument on Brain-First and Body-First Pathogenesis of Lewy Body Disease.

OBJECTIVE: To explore the clinical progression of the brain-/body-first categories within Lewy body disease (LBD): Parkinson's disease (PD), dementia with Lewy bodies (DLB), and PD dementia. METHODS: We used of the Rochester Epidemiology Project to establish a population-based cohort of clinically diagnosed LBD. We used two definitions for differentiating between brain- and body-first LBD: a previously hypothesized body-first presentation in patients with rapid eye movement sleep behavior onset before motor symptoms onset; and an expanded definition of body-first LBD when a patient had at least 2 premotor symptoms between constipation, erectile dysfunction, rapid eye movement sleep behavior, anosmia, or neurogenic bladder. RESULTS: Brain-first patients were more likely to be diagnosed with PD (RR = 1.43, p = 0.003), whereas body-first patients were more likely to be diagnosed with DLB (RR = 3.15, p < 0.001). Under the expanded definition, there was no difference in LBD diagnosis between brain-first and body-first patients (PD: RR = 1.03, p = 0.10; DLB: RR = 0.88, p = 0.58) There were no patterns between brain- or body-first presentation, PD dementia under either definition (original: p = 0.09, expanded: p = 0.97), and no significant difference in motor symptoms between brain-first and body-first. INTERPRETATION: Our findings do not support the dichotomous classification of body-first and brain-first LBD with the currently proposed definition. Biological exposures resulting in PD and DLB are unlikely to converge on a binary classification of top-down or bottom-up synuclein pathology. ANN NEUROL 2024;96:551-559.

Predictors of the Rapid Progression in Prodromal Parkinson's Disease: A Longitudinal Follow-Up Study.

INTRODUCTION: Parkinson's disease (PD) is characterized by a prodromal phase preceding the onset of classic motor symptoms. The duration and clinical manifestations of prodromal PD vary widely, indicating underlying heterogeneity within this stage. This discrepancy prompts the question of whether specific factors contribute to the divergent rates of progression in prodromal PD. METHODS: This study included prodromal PD patients from the Parkinson's progression marker initiative. They were followed up to assess the disease progression. The data collected during the follow-up period were analyzed to identify potential predictors of rapid disease progression in prodromal PD. RESULTS: In this study, 61 individuals with prodromal PD were enrolled. Among them, 43 patients presented with both RBD and hyposmia, 17 had hyposmia alone, and 1 had RBD alone at baseline. 13 (21.3%) prodromal PD participants exhibited rapid disease progression, with two of these cases advancing to non-neurological diseases. Significant differences were observed between the rapid progression group and no rapid progression group in terms of MDS-UPDRS II score and UPSIT score. Longitudinal analysis showed a significant increase in the MDS-UPDRS III score and MDS-UPDRS total score in the rapid progression group. Regression analyses identified the MDS-UPDRS II score and UPSIT score as predictors of rapid disease progression in prodromal PD. CONCLUSION: Our study findings suggest that the MDS-UPDRS II score and UPSIT score may serve as clinical markers associated with rapid disease progression. Further research and development of precise biomarkers and advanced assessment methods are needed to enhance our understanding of prodromal PD and its progression patterns.

Symmetric and Profound Monoaminergic Degeneration in Parkinson's Disease with Premotor REM Sleep Behavior Disorder.

Background: Rapid eye movement sleep behavior disorder (RBD) may precede or follow motor symptoms in Parkinson's disease (PD). While over 70% of idiopathic RBD cases phenoconvert within a decade, a small subset develops PD after a more extended period or remains nonconverted. These heterogeneous manifestations of RBD in PD prompt subtype investigations. Premotor RBD may signify "body-first" PD with bottom-up, symmetric synucleinopathy propagation. Objective: Explore brainstem and nigrostriatal monoaminergic degeneration pattern differences based on premotor RBD presence and duration in de novo PD patients. Methods: In a cross-sectional analysis of de novo PD patients (n = 150) undergoing FP-CIT PET and RBD Single-Question Screen, the cohort was categorized into groups with and without premotor RBD (PDRBD +/-), with further classification of PDRBD + based on a 10-year duration of premotor RBD. Analysis of FP-CIT binding in the striatum and pons, striatal asymmetry, and striatum-to-pons ratios compared patterns of nigrostriatal and brainstem monoaminergic degeneration. Results: PDRBD + exhibited more severe and symmetrical striatal dopaminergic denervation compared to PDRBD-, with the difference in severity accentuated in the least-affected hemisphere. The PDRBD +<10Y subgroup displayed the most prominent striatal symmetry, supporting a more homogeneous "body-first" subtype. Pontine uptakes remained lower in PDRBD + even after adjusting for striatal uptake, suggesting early degeneration of pontine monoaminergic nuclei. Conclusions: Premotor RBD in PD is associated with severe, symmetrical nigrostriatal and brainstem monoaminergic degeneration, especially in cases with PD onset within 10 years of RBD. This supports the concept of a "widespread, bottom-up" pathophysiological mechanism associated with premotor RBD in PD.

Secondary RBD: Not just neurodegeneration.

Rapid eye movement sleep behavior disorder is a parasomnia characterized by excessive muscle activity during rapid eye movement sleep (rapid eye movement sleep without atonia), along with dream enactment behavior. Isolated rapid eye movement sleep behavior disorder tends to occur in older males and is of concern due to the known link to Parkinson's disease and other synucleinopathies. When rapid eye movement sleep behavior disorder occurs in association with other neurological or general medical conditions, or resulting from the use of various substances, it is called secondary rapid eye movement sleep behavior disorder; the most common cause is neurodegenerative illness, specifically the synucleinopathies. Here, the focus will be on the subset of secondary rapid eye movement sleep behavior disorder in which there is no neurodegenerative disease.

Cognition and Other Non-Motor Symptoms in an At-Risk Cohort for Parkinson's Disease Defined by REM-Sleep Behavior Disorder and Hyposmia.

Background: REM-sleep behavior disorder (RBD) and other non-motor symptoms such as hyposmia were proposed by the Movement Disorder Society as research criteria for prodromal Parkinson's disease (P-PD). Global cognitive deficit was later added. Objective: To compare non-motor symptoms, focusing on cognition, between a P-PD group and a matched control group. Methods: In this cross-sectional, case-control study, in a first set of analyses, we performed extensive cognitive testing on people with (n = 76) and a control group without (n = 195) probable RBD and hyposmia. Furthermore, we assessed motor and non-motor symptoms related to Parkinson's Disease (PD). After propensity score matching, we compared 62 P-PD with 62 age- and sex-matched controls. In addition, we performed regression analyses on the total sample (n = 271). In a second set of analyses, we used, a.o., the CUPRO to evaluate retrograde procedural memory and visuo-constructive functions. Results: People with P-PD showed significantly poorer performances in global cognition, visuo-constructive and executive functions, mainly in mental flexibility (p < 0.001; p = 0.004; p = 0.003), despite similar educational levels (p = 0.415). We observed significantly more motor and non-motor symptoms (p < 0.001; p = 0.004), higher scores for depression (p = 0.004) and apathy (p < 0.001) as well as lower quality of life (p < 0.001) in P-PD. CONCLUSIONS: Our findings confirm that global cognitive, executive, and visuo-constructive deficits define the P-PD group. In addition, depression, apathy, and lower quality of life were more prevalent in P-PD. If replicated in other samples, executive and visuo-constructive deficits should be considered in non-motor P-PD. Determining specific patterns will support early recognition of PD, secondary prevention of complications and the development of neuroprotective treatments.

[Early cortical atrophy in REM sleep behavior disorder]. / Atrofia cortical precoz en el trastorno de conducta del sueño REM.

INTRODUCTION: The presence of cortical atrophy (focal or diffuse) prior to the development of symptoms of cognitive impairment could predict the earliest cases of neurodegenerative disease in patients with REM sleep behavior disorder (RSBD). We reviewed the usefulness of cranial CT and MRI as early markers of cortical atrophy in patients with RSBD at our center. PATIENTS AND METHODS: Retrospective observational descriptive analysis of patients diagnosed with RSBD from October 2012 to October 2022. All with cranial CT or MRI, evaluated by a neuroradiologist. RESULTS: 54 patients were included, 21 women (38.88%), 33 men (61.12%), mean age at diagnosis of RSBD: 69.04±12.625 years. Of the 54 patients, 44 (81.48%) had imaging tests consistent with their age, and 10 had atrophy greater than expected for their age. Of the 54 patients, 21 (38.88%) with a diagnosis of neurodegenerative disease, 33 (61.12%) persist as idiopathic, almost all with more than 5years of evolution (range of 1 to 10years of evolution without diagnosis). Of the 10 (18.52%) patients with greater atrophy, all were diagnosed with neurodegenerative disease (8 in 1year, 2 in 8years). CONCLUSIONS: Almost half of our series have developed a neurodegenerative disease in the first 10years of evolution. The majority of them presented global cortical atrophy measured by the GCA scale in the first year of diagnosis, without other neurological symptoms. Patients who did not show cortical atrophy at diagnosis have not yet developed the neurodegenerative disease in 10years of evolution. In our experience, the absence of cortical atrophy on cranial MRI or CT (measured by scales such as GCA) at the diagnosis of RSBD seems to predict slower progression cases. These data should be corroborated with larger series.

Perspectives of People At-Risk on Parkinson's Prevention Research.

 The movement toward prevention trials in people at-risk for Parkinson's disease (PD) is rapidly becoming a reality. The authors of this article include a genetically at-risk advocate with the LRRK2 G2019 S variant and two patients with rapid eye movement sleep behavior disorder (RBD), one of whom has now been diagnosed with PD. These authors participated as speakers, panelists, and moderators in the "Planning for Prevention of Parkinson's: A Trial Design Forum" hosted by Massachusetts General Hospital in 2021 and 2022. Other authors include a young onset person with Parkinson's (PwP) and retired family physician, an expert in patient engagement in Parkinson's, and early career and veteran movement disorders clinician researchers. Several themes emerged from the at-risk participant voice concerning the importance of early intervention, the legitimacy of their input in decision-making, and the desire for transparent communication and feedback throughout the entire research study process. Challenges and opportunities in the current environment include lack of awareness among primary care physicians and general neurologists about PD risk, legal and psychological implications of risk disclosure, limited return of individual research study results, and undefined engagement and integration of individuals at-risk into the broader Parkinson's community. Incorporating the perspectives of individuals at-risk as well as those living with PD at this early stage of prevention trial development is crucial to success.

Longitudinal brain changes in Parkinson's disease with severe olfactory deficit.

INTRODUCTION: Olfactory dysfunction and REM sleep behavior disorder (RBD) are associated with distinct cognitive trajectories in the course of Parkinson's disease (PD). The underlying neurobiology for this relationship remains unclear but may involve distinct patterns of neurodegeneration. This study aimed to examine longitudinal cortical atrophy and thinning in early-stage PD with severe olfactory deficit (anosmia) without and with concurrent probable RBD. METHODS: Longitudinal MRI data over four years of 134 de novo PD and 49 healthy controls (HC) from the Parkinson Progression Marker Initiative (PPMI) cohort were analyzed using a linear mixed-effects model. Patients were categorized into those with anosmia by the University of Pennsylvania Smell Identification Test (UPSIT) score ≤ 18 (AO+) and those without (UPSIT score > 18, AO-). The AO+ group was further subdivided into AO+ with probable RBD (AO+RBD+) and without (AO+RBD-) for subanalysis. RESULTS: Compared to subjects without baseline anosmia, the AO+ group exhibited greater longitudinal declines in both volume and thickness in the bilateral parahippocampal gyri and right transverse temporal gyrus. Patients with concurrent anosmia and RBD showed more extensive longitudinal declines in cortical volume and thickness, involving additional brain regions including the bilateral precuneus, left inferior temporal gyrus, right paracentral gyrus, and right precentral gyrus. CONCLUSIONS: The atrophy/thinning patterns in early-stage PD with severe olfactory dysfunction include regions that are critical for cognitive function and could provide a structural basis for previously reported associations between severe olfactory deficit and cognitive decline in PD. Concurrent RBD might enhance the dynamics of cortical changes.

[Hitting and yelling during sleep: diagnosis and implications of REM sleep behavior disorder]. / Slaan en schreeuwen in de slaap.

Rapid eye movement (REM) sleep behavior disorder is characterized by dream enactment during REM sleep. Due to different treatment requirements, it is important to distinguish REM sleep behavior disorder from other causes of nocturnal restlessness, including sleep apnea, non-REM parasomnia and sleep-related hypermotor epilepsy. In addition, a diagnosis of isolated REM sleep behavior disorder is impactful, because it carries a greatly increased risk for the later development of Parkinson's disease and related synucleinopathies. In this clinical lesson we describe three patients with abnormal nocturnal movements and vocalizations. The history can provide important clues towards the diagnosis, but a video-polysomnography is required before REM sleep behavior disorder can be diagnosed.

Parkinson's disease motor progression in relation to the timing of REM sleep behavior disorder presentation: an exploratory retrospective study.

REM sleep behavior disorder (RBD) is a frequent non-motor symptom of Parkinson's disease (PD), and the timing of its presentation might have a role in the underlying neurodegenerative process. Here, we aimed to define the potential impact of probable RBD (pRBD) on PD motor progression.We conducted a longitudinal retrospective study on 66 PD patients followed up at the University Hospital of Rome Tor Vergata. Patients were divided into three groups: with post-motor pRBD (pRBDpost, n = 25), without pRBD (pRBDwo, n = 20), and with pre-motor pRBD (pRBDpre, n = 21). Hoehn and Yahr (H&Y) scores, Unified PD Rating Scale (UPDRS) motor scores, and levodopa equivalent daily dose were collected at two follow-up visits conducted in a 5-year interval (T0 and T1). pRBDpost patients had a greater rate of motor progression in terms of the H&Y scale compared to pRBDpre and pRBDwo patients, without the influence of anti-parkinsonian treatment.These preliminary findings suggest that the post-motor occurrence of pRBD can be associated with an acceleration in PD motor progression.

Impaired Mitochondrial Respiration in REM-Sleep Behavior Disorder: A Biomarker of Parkinson's Disease?

BACKGROUND: Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is associated with prodromal Parkinson's disease (PD), but the mechanisms linking phenoconversion of iRBD to PD have not yet been clarified. Considering the association between mitochondrial dysfunction and sleep disturbances in PD, we explored mitochondrial activity in fibroblasts derived from iRBD patients to identify a biochemical profile that could mark the presence of impending neurodegeneration. METHODS: The study involved 28 participants, divided into three groups: patients diagnosed with iRBD, PD patients converted from iRBD (RBD-PD), and healthy controls. We performed a comprehensive assessment of mitochondrial function, including an examination of mitochondrial morphology, analysis of mitochondrial protein expression levels by western blot, and measurement of mitochondrial respiration using the Seahorse XFe24 analyzer. RESULTS: In basal conditions, mitochondrial respiration did not differ between iRBD and control fibroblasts, but when cells were challenged with a higher energy demand, iRBD fibroblasts exhibited a significant (P = 0.006) drop in maximal and spare respiration compared to controls. Interestingly, RBD-PD patients showed the same alterations with a further significant reduction in oxygen consumption linked to adenosine triphosphate production (P = 0.032). Moreover, RBD-PD patients exhibited a significant decrease in protein levels of complexes III (P = 0.02) and V (P = 0.002) compared to controls, along with fragmentation of the mitochondrial network. iRBD patients showed similar, but milder alterations. CONCLUSIONS: Altogether, these findings suggest that mitochondrial dysfunctions in individuals with iRBD might predispose to worsening of the bioenergetic profile observed in RBD-PD patients, highlighting these alterations as potential predictors of phenoconversion to PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Prevalence and clinical aspects of obstructive sleep apnea in Parkinson disease: A meta-analysis.

BACKGROUND AND PURPOSE: Obstructive sleep apnea (OSA) frequently occurs in Parkinson Disease (PD), probably caused by upper airway dysfunctions or shared pathogenetic mechanisms. OSA may precede PD diagnosis or worsen throughout its course, but its relationship with clinical features and dopaminergic medication remains unclear. This meta-analysis aimed to provide a reliable estimate of OSA prevalence in the PD population (PD-OSA) and to clarify its clinical associated factors to help clinicians in understanding the underlying pathophysiological mechanisms. METHODS: A systematic literature search was performed up to April 2023 using the PubMed, Scopus, and PsycINFO databases. Articles were included if they provided data on PD patients with and without OSA. Pooled prevalence for PD-OSA was calculated using the proportions of PD participants diagnosed with OSA. Demographic and clinical features associated with PD-OSA were explored by comparing PD patients with and without OSA. RESULTS: Seventeen studies were included in the meta-analysis. Pooled OSA prevalence was 45% of a total sample of 1448 PD patients and was associated with older age, male sex, higher body mass index (BMI), more severe motor disturbances and periodic limb movements, reduced risk of rapid eye movement sleep behavior disorder, intake of dopamine agonists, and worse excessive daytime sleepiness. No relationship emerged with cognitive functioning and neuropsychiatric manifestations. CONCLUSIONS: OSA affects nearly half of PD patients as a secondary outcome of predisposing factors such as older age and higher BMI in addition to PD-related motor impairment. Future studies should focus on determining the impact of both clinical features and dopaminergic medication on the development of PD-OSA.

REM sleep behavior disorder: update on diagnosis and management.

REM sleep behavior disorder (RBD) is characterized by a loss of atonia of skeletal muscles during REM sleep, associated with acting out behaviors during dreams. Knowledge of this pathology is important to predict neurodegenerative diseases since there is a strong association of RBD with diseases caused by the deposition of alpha-synuclein in neurons (synucleinopathies), such as Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB). Proper diagnosis of this condition will enable the use of future neuroprotective strategies before motor and cognitive symptoms. Diagnostic assessment should begin with a detailed clinical history with the patient and bed partner or roommate and the examination of any recorded home videos. Polysomnography (PSG) is necessary to verify the loss of sleep atonia and, when documented, the behaviors during sleep. Technical recommendations for PSG acquisition and analysis are defined in the AASM Manual for the scoring of sleep and associated events, and the PSG report should describe the percentage of REM sleep epochs that meet the criteria for RWA (REM without atonia) to better distinguish patients with and without RBD. Additionally, PSG helps rule out conditions that may mimic RBD, such as obstructive sleep apnea, non-REM sleep parasomnias, nocturnal epileptic seizures, periodic limb movements, and psychiatric disorders. Treatment of RBD involves guidance on protecting the environment and avoiding injuries to the patient and bed partner/roommate. Use of medications are also reviewed in the article. The development of neuroprotective medications will be crucial for future RBD therapy.

O transtorno comportamental do sono REM (TCSREM) é caracterizado por uma perda de atonia dos músculos esqueléticos durante o sono REM, associada a comportamentos de atuação durante os sonhos. O conhecimento desse transtorno é importante como preditor de doenças neurodegenerativas, uma vez que existe uma forte associação de TCSREM com doenças causadas pela deposição de alfa-sinucleína nos neurônios, como a doença de Parkinson (DP), atrofia de múltiplos sistemas (MSA) e demência com corpos de Lewy (DLB). O diagnóstico adequado dessa condição permitirá o uso de futuras estratégias neuroprotetoras antes do aparecimento dos sintomas motores e cognitivos. A avaliação diagnóstica deve começar com uma história clínica detalhada com o paciente e acompanhante, além de exame de vídeos. A polissonografia (PSG) é necessária para verificar a perda da atonia do sono e, quando documentados, os comportamentos durante o sono. As recomendações técnicas para aquisição e análise de PSG são definidas no Manual da AASM (Scoring of sleep and associated events) e o relatório de PSG deve descrever a porcentagem de períodos de sono REM que atendem aos critérios para REM sem atonia. Além disso, a PSG ajuda a descartar condições que podem mimetizar o TCSREM, como apneia obstrutiva do sono, parassonias do sono não REM, crises epilépticas noturnas, movimentos periódicos dos membros e transtornos psiquiátricos. O tratamento do TCSREM envolve orientações sobre adaptações do ambiente para evitar lesões ao paciente e ao colega de quarto. Medicamentos utilizados são revistos no artigo, assim como o crucial desenvolvimento de medicamentos neuroprotetores.

Autonomic dysregulation during sleep in Parkinsonian spectrum disorders - A proof of concept.

INTRODUCTION: Autonomic dysfunction is common in α-synucleinopathies such as Lewy Body dementias (LBD), Parkinson's disease (PD), and isolated REM Sleep Behavior Disorder (iRBD). We analyzed pulse-rate changes during sleep to index autonomic nervous system (ANS) dysfunction in patients with α-synucleinopathies vs. non-synucleinopathy groups expected to have normal ANS function. METHODS: Patients with LBD (n = 16), PD (PD, n = 14) or iRBD (n = 12) were compared to the non-synucleinopathy groups Alzheimers disease dementia (ADem, n = 26), mild cognitive impairment (MCI, n = 34) or controls (CG, n = 54). Sleep Profiler was used to derive a sleep autonomic activation index (AAI), i.e., ≥6 beat-per-minute increase/decrease, pulse rate coefficient of variation (PR-CV), and automated sleep staging with sleep-spindles and non-REM hypertonia (NRH). Analysis included statistical group comparisons and receiver operating characteristics curves to determine optimal classification of groups. RESULTS: AAI and PR-CV were moderately correlated across all recordings (rs = 0.58, P < 0.0001), except in the LBD and PD groups. AAI but not PR-CV differentiated the LBD, PD and iRBD from non-Parkinsonian groups. AAI was decreased in LBD and PD patients compared to the CG (p < 0.003) and MCI (p < 0.03). AAI decreased based on age and its receiver operating characteristic area under the curve ranged from 0.63 to 0.75. AAI had a weak negative correlation to NRH (rs ≤ -0.26) but not sleep-spindles. CONCLUSION: Synucleinopathy-related ANS dysfunction can reasonably discriminate prodromal and manifest PD/LBD diseased groups from non-synucleinopathies. Further studies incorporating AAI into a multivariate classifier of neurodegenerative disorders based on sleep characteristics acquired in the patient's home are planned.

To know or not to know? Opinions of patients with Parkinson's Disease on disclosing risk of phenoconversion in RBD.

INTRODUCTION: The aim of our study was to find out the opinion of patients with Parkinson's Disease (PD) whose disease was preceded by REM sleep behaviour disorder (RBD) regarding early information about the high risk of phenoconversion in RBD. CLINICAL RATIONALE FOR THE STUDY: RBD is an early clinical manifestation of α-synucleinopathies with a more than 90% risk of phenoconversion to PD, dementia with Lewy bodies (DLB) or multiple system atrophy (MSA). It remains a subject for debate as to whether and how RBD patients should be informed about the high risk of phenoconversion. The patient's right to full knowledge regarding his or her health conflicts with the potentially destructive impact of this information on his or her mental state and quality of life of them and their relatives. MATERIAL AND METHODS: Thirty-nine patients with PD whose disease was preceded by RBD were surveyed. Data on the course of RBD and PD was collected. Questions were asked about early information about the high risk of phenoconversion to patients with RBD and factors determining the opinion of the surveyed persons. RESULTS: The majority ( > 60%) of respondents gave a positive answer when asked whether patients should be informed about their high risk of developing PD once diagnosed with RBD. Only a few (7.7%) respondents believed that disclosing such information to the patient should be possible only after obtaining his or her consent. Respondents associated consent to information about the high risk of developing PD in people with RBD with high expectations of the healthcare system. We were unable to determine whether factors such as the gender of the subject, the clinical course of the PD, and the RBD duration had an impact on patients' opinions regarding disclosing knowledge about phenoconversion. CONCLUSIONS AND CLINICAL IMPLICATIONS: Our study provides important information that should influence physicians' communication with patients with RBD, especially regarding how they communicate about the high risk of phenoconversion.

Overnight Distribution of REM Sleep Features in People with Parkinson's Disease (PD) and Non-PD Controls.

BACKGROUND: Rapid eye movement (REM) sleep behavior disorder (RBD) is a leading predictor of Parkinson's disease (PD). Diagnosis is performed in the sleep laboratory by detecting pathological REM sleep without atonia (RSWA). The evidence on the overnight distribution of RSWA% is conflicting. OBJECTIVE: To investigate the temporal distribution of the number of ocular movements per REM sleep minute (REM density), and RSWA% in people with PD and non-PD controls. METHODS: All participants underwent a single overnight evaluation in a sleep laboratory. Clinical evaluation was performed on a separate day. REM density and RSWA% were compared between PD and controls both across four sleep periods and individual REM cycles. RESULTS: A total of 51 participants with recorded RSWA in polysomnography laboratory were included, 28 with PD aged 64±9 years with a disease duration of 3.3±2.9 years, and 23 controls aged 55±8 years. People with PD had lower REM density and higher RSWA% compared to controls. As expected, REM density was higher towards the morning. In contrast, RSWA% was equally distributed across the night, for both PD and controls. CONCLUSIONS: PD pathology affects REM sleep features, but not the overnight distribution of those features. While REM density increased towards the end of the night, RSWA% was equally distributed across the night for both PD and controls. Our findings have clinical implications for diagnosing RBD, as quantification of RSWA% in any sleep cycle is sufficient for reliably evaluating total RSWA% and reduced REM density may be a marker of PD.