Cognitive training and promoting a healthy lifestyle for individuals with isolated REM sleep behavior disorder: study protocol of the delayed-start randomized controlled trial CogTrAiL-RBD.

BACKGROUND: Isolated REM sleep behavior disorder (iRBD) is an early α-synucleinopathy often accompanied by incipient cognitive impairment. As executive dysfunctions predict earlier phenotypic conversion from iRBD to Parkinson's disease and Lewy body dementia, cognitive training focusing on executive functions could have disease-modifying effects for individuals with iRBD. METHODS: The study CogTrAiL-RBD investigates the short- and long-term effectiveness and the feasibility and underlying neural mechanisms of a cognitive training intervention for individuals with iRBD. The intervention consists of a 5-week digital cognitive training accompanied by a module promoting a healthy, active lifestyle. In this monocentric, single-blinded, delayed-start randomized controlled trial, the intervention's effectiveness will be evaluated compared to an initially passive control group that receives the intervention in the second, open-label phase of the study. Eighty individuals with iRBD confirmed by polysomnography will be consecutively recruited from the continuously expanding iRBD cohort at the University Hospital Cologne. The evaluation will focus on cognition and additional neuropsychological and motor variables. Furthermore, the study will examine the feasibility of the intervention, effects on physical activity assessed by accelerometry, and interrogate the intervention's neural effects using magnetic resonance imaging and polysomnography. Besides, a healthy, age-matched control group (HC) will be examined at the first assessment time point, enabling a cross-sectional comparison between individuals with iRBD and HC. DISCUSSION: This study will provide insights into whether cognitive training and psychoeducation on a healthy, active lifestyle have short- and long-term (neuro-)protective effects for individuals with iRBD. TRIAL REGISTRATION: The study was prospectively registered in the German Clinical Trial Register (DRKS00024898) on 2022-03-11, https://drks.de/search/de/trial/DRKS00024898 . PROTOCOL VERSION: V5 2023-04-24.

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.

Exploring the network effects of deep brain stimulation for rapid eye movement sleep behavior disorder in Parkinson's disease.

BACKGROUND: The research findings on the effects of subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) with Rapid Eye Movement Sleep Behavior Disorder (RBD) are inconsistent, and there is a lack of research on DBS electrode sites and their network effects for the explanation of the differences. Our objective is to explore the optimal stimulation sites (that is the sweet spot) and the brain network effects of STN-DBS for RBD in PD. METHODS: In this study, among the 50 PD patients who underwent STN-DBS treatment, 24 PD patients with RBD were screened. According to clinical scores and imaging data, the sweet spot of STN-DBS was analyzed in PD patients with RBD, and the optimal structure and functional network models of subthalamic stimulation were constructed. RESULTS: Bilateral STN-DBS can effectively improve the symptoms of RBD and other non-motor symptoms in 24 PD patients with RBD. RBD Questionnaire-Hong Kong (RBDQ-HK) score was 41.33 ± 17.45 at baseline and 30.83 ± 15.83 at 1-year follow-up, with statistical significance between them (P < 0.01). However, the MoCA score was an exception with a baseline of 22.04 ± 4.28 and a 1-year follow-up of 21.58 ± 4.33, showing no statistical significance (P = 0.12). The sweet spot and optimal network connectivity models for RBD improvement have been validated as effective. CONCLUSIONS: Bilateral STN-DBS can improve the symptoms of RBD in PD. There exist the sweet spot and brain network effects of bilateral STN-DBS in the treatment of PD with RBD. Our study also demonstrates that RBD is a brain network disease.

REM behavior disorder: When Parkinson's disease meets Morpheus.

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by the absence of normal muscle atonia during REM sleep, resulting in excessive motor activity while dreaming. RBD can be classified as isolated which is the strongest clinical marker of prodromal synucleinopathy, or secondary, associated with other neurological diseases, mainly Parkinson's disease (PD) and dementia with Lewy bodies. The diagnosis of RBD must be systematically documented by a video polysomnography in the case of isolated RBD. PD associated with RBD may represent a distinct phenotype compared to PD without RBD, indicating a more severe and widespread synucleinopathy. Clinically, it is associated with poorer motor and cognitive performance, more severe non-motor symptoms, and faster disease progression. Imaging studies have revealed broader brain damage and significant alterations in cerebral metabolism and neurotransmission in PD patients with RBD. The management of RBD involves safety precautions and pharmacotherapy. Safety measures aim to minimize the risk of injury during RBD episodes and include creating a safe sleeping environment and separating the patient from their bed partner if necessary. Pharmacotherapy options include clonazepam and melatonin. Clonazepam must be cautiously prescribed in older patients due to potential side effects.

Prefrontal association of subthalamic deep brain stimulation with rapid eye movement sleep behavior disorder in Parkinson's disease.

OBJECTIVE: Subthalamic nucleus (STN)-deep brain stimulation (DBS) in Parkinson's disease (PD) patients affects not just focused target areas but also diffuse brain networks. The effect of this network modulation on nonmotor DBS effects is not fully understood. By concentrating on the sleep domain, the authors comprehensively determined the influence of electrode location and related structural/functional connections on changes in probable rapid eye movement (REM) sleep behavior disorder (pRBD) symptoms after STN-DBS, which has been reported to ameliorate, deteriorate, or remain constant. METHODS: Preoperative and postoperative pRBD symptoms were documented in 60 PD patients. The volumes of tissue activated (VTAs) were assessed on the basis of individual electrode reconstructions and merged with normative connectome data to identify structural/functional connections associated with VTAs. The entire cohort was used to construct connection models that explained changes in pRBD symptoms, as well as to perform cross-validations. RESULTS: Structural/functional connectivity was associated with pRBD symptom changes during STN-DBS. Changes in pRBD symptoms were predicted using an ideal structural connection map. Prefrontal connection was related with improved pRBD symptoms, whereas sensorimotor connectivity was associated with deterioration. CONCLUSIONS: Recovery of pRBD symptoms was predicted on the basis of the fibers connecting the STN electrode to prefrontal regions. These findings implied that the placement of STN-DBS leads influences the fibers to prefrontal regions and may be used to enhance treatment of pRBD symptoms; however, further prospective studies are needed to validate these findings.

Management of REM sleep behavior disorder: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment.

This systematic review provides supporting evidence for a clinical practice guideline for the management of rapid eye movement (REM) sleep behavior disorder in adults and children. The American Academy of Sleep Medicine commissioned a task force of 7 experts in sleep medicine. A systematic review was conducted to identify randomized controlled trials and observational studies that addressed interventions for the management of REM sleep behavior disorder in adults and children. Statistical analyses were performed to determine the clinical significance of critical and important outcomes. Finally, the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations. The literature search identified 4,690 studies; 148 studies provided data suitable for statistical analyses; evidence for 45 interventions is presented. The task force provided a detailed summary of the evidence assessing the certainty of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations. CITATION: Howell M, Avidan AY, Foldvary-Schaefer N, et al. Management of REM sleep behavior disorder: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment. J Clin Sleep Med. 2023;19(4):769-810.

Management of Sleep Disturbances in Parkinson's Disease.

Parkinson's disease (PD) is defined by its motor symptoms rigidity, tremor, and akinesia. However, non-motor symptoms, particularly autonomic disorders and sleep disturbances, occur frequently in PD causing equivalent or even greater discomfort than motor symptoms effectively decreasing quality of life in patients and caregivers. Most common sleep disturbances in PD are insomnia, sleep disordered breathing, excessive daytime sleepiness, REM sleep behavior disorder, and sleep-related movement disorders such as restless legs syndrome. Despite their high prevalence, therapeutic options in the in- and outpatient setting are limited, partly due to lack of scientific evidence. The importance of sleep disturbances in neurodegenerative diseases has been further emphasized by recent evidence indicating a bidirectional relationship between neurodegeneration and sleep. A more profound insight into the underlying pathophysiological mechanisms intertwining sleep and neurodegeneration might lead to unique and individually tailored disease modifying or even neuroprotective therapeutic options in the long run. Therefore, current evidence concerning the management of sleep disturbances in PD will be discussed with the aim of providing a substantiated scaffolding for clinical decisions in long-term PD therapy.

Isolated rapid eye movement sleep behavior disorder combined with obstructive sleep apnea: response to treatment and its associated factors.

OBJECTIVE/BACKGROUND: When isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is combined with obstructive sleep apnea (OSA), the pattern of temporal association between REM without atonia (RWA) and apnea-hypopnea events may be related to improvements in RBD symptoms after positive airway pressure (PAP) treatment. We evaluated the frequency of improvement in RBD symptoms after PAP and the relationship of the degree of co-occurrence between RWA and apnea-hypopnea events to RBD symptom improvement after PAP treatment. PATIENTS/METHODS: In an institutional cohort with sleep disorders, 31 patients with video-polysomnography confirmed iRBD and concomitant OSA with an apnea-hypopnea index (AHI) of ≥15/h who received PAP treatment were included. Along with gross video-polysomnography parameters such as AHI and electromyography activity index during REM sleep, a mini-epoch-based parameter apnea-hypopnea-electromyography activity ratio (AH EMG activity ratio) was used to evaluate the co-occurrence between RWA and apnea-hypopnea events. Improvement in RBD symptoms after PAP treatment was designated as a clinical global impression-improvement (CGI-I) score of 0-3 at three-month. RESULTS: Twenty-three (74.2%) patients exhibited improvement in RBD symptoms after PAP treatment. No patient was taking an antidepressant medication. An AH EMG activity ratio of ≥15% (Odds ratio [OR] 10.146, 95% CI 1.302-79.032, P = 0.027) was significantly associated with clinical improvement after PAP treatment in a regression model adjusted for age, sex, AHI, and electromyography activity index during REM. CONCLUSIONS: Treatment of concomitant OSA with PAP can improve symptoms of iRBD. Respiratory events that co-occur with RWA may predict improvement in RBD symptoms after PAP treatment.

Current Update on Clinically Relevant Sleep Issues in Parkinson's Disease: A Narrative Review.

Sleep disturbances are among the common nonmotor symptoms in patients with Parkinson's disease (PD). Sleep can be disrupted by nocturnal motor and nonmotor symptoms and other comorbid sleep disorders. Rapid eye movement sleep behavior disorder (RBD) causes sleep-related injury, has important clinical implications as a harbinger of PD and predicts a progressive clinical phenotype. Restless legs syndrome (RLS) and its related symptoms can impair sleep initiation. Excessive daytime sleepiness (EDS) is a refractory problem affecting patients' daytime activities. In particular, during the COVID-19 era, special attention should be paid to monitoring sleep problems, as infection-prevention procedures for COVID-19 can affect patients' motor symptoms, psychiatric symptoms and sleep. Therefore, screening for and managing sleep problems is important in clinical practice, and the maintenance of good sleep conditions may improve the quality of life of PD patients. This narrative review focused on the literature published in the past 10 years, providing a current update of various sleep disturbances in PD patients and their management, including RBD, RLS, EDS, sleep apnea and circadian abnormalities.

A case series and systematic review of rapid eye movement sleep behavior disorder outcome after deep brain stimulation in Parkinson's disease.

REM-sleep behavior disorder (RBD) is a parasomnia and a common sleep disorder in Parkinson's disease (PD). While deep brain stimulation (DBS) is an established treatment for advanced PD with beneficial effects on cardinal PD motor symptoms, the data on the impact of DBS on RBD are limited and often controversial. We reviewed published articles that reported on RBD in the context of DBS surgery via systematic PubMed search. We identified 75 studies and included 12 studies, involving a total of 320 subjects, in our review. Results in respect to EMG activity outcome after subthalamic stimulation are inconsistent. We found no study that reported on RBD outcome after pallidal DBS and no DBS study quantified complex behavior during REM sleep. We also added data on RBD outcome after subthalamic (N = 4 patients) or pallidal (N = 3 patients) DBS from patients with PD with RBD, obtained as part of a prospective DBS study in our centre. Our case series showed an increase of complex behavior during REM (CB-REM) after surgery, independent of DBS target. Conversely, we found a trend towards increasing REM sleep without atonia (RSWA) in subthalamic-stimulated patients and a trend towards decreased RSWA in pallidal stimulated patients. We conclude that CB-REM and RSWA might represent two distinct elements in RBD and should be assessed separately, especially in studies that report on RBD outcome after treatment interventions. Further, larger, prospective, controlled studies in different DBS targets, reporting separately on the different RBD modalities, are needed.

Current Concepts and Controversies in the Management of REM Sleep Behavior Disorder.

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by dream enactment and the loss of muscle atonia during REM sleep, known as REM sleep without atonia (RSWA). RBD can result in significant injuries, prompting patients to seek medical attention. However, in others, it may present only as non-violent behaviors noted as an incidental finding during polysomnography (PSG). RBD typically occurs in the context of synuclein-based neurodegenerative disorders but can also be seen accompanying brain lesions and be exacerbated by medications, particularly antidepressants. There is also an increasing appreciation regarding isolated or idiopathic RBD (iRBD). Symptomatic treatment of RBD is a priority to prevent injurious complications, with usual choices being melatonin or clonazepam. The discovery that iRBD represents a prodromal stage of incurable synucleinopathies has galvanized the research community into delineating the pathophysiology of RBD and defining biomarkers of neurodegeneration that will facilitate future disease-modifying trials in iRBD. Despite many advances, there has been no progress in available symptomatic or neuroprotective therapies for RBD, with recent negative trials highlighting several challenges that need to be addressed to prepare for definitive therapeutic trials for patients with this disorder. These challenges relate to i) the diagnostic and screening strategies applied to RBD, ii) the limited evidence base for symptomatic therapies, (iii) the existence of possible subtypes of RBD, (iv) the relevance of triggering medications, (v) the absence of objective markers of severity, (vi) the optimal design of disease-modifying trials, and vii) the implications around disclosing the risk of future neurodegeneration in otherwise healthy individuals. Here, we review the current concepts in the therapeutics of RBD as it relates to the above challenges and identify pertinent research questions to be addressed by future work.

The probable REM sleep behavior disorder negatively affects health-related quality of life in Parkinson's disease with bilateral subthalamic nucleus stimulation.

OBJECTIVE: The aim of this study was to compare the short- and long-term outcomes of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD) patients with and without probable REM sleep behavior disorder (RBD). METHODS: We retrospectively reviewed 127 patients who underwent bilateral STN-DBS for PD with probable RBD from September 2011 to November 2018. Motor performance, physical and mental health-related quality of life (HRQoL), cognitive function, and depressive severity were compared between with or without probable RBD at the baseline and at the 1-, 3- or 5-year follow-up. RESULTS: One hundred three PD patients (55 with RBD; 48 without RBD) were evaluated at the baseline and at the 1-year follow-up and 33 (17 with RBD, 16 without RBD) of them were examined at the 5-year follow-up. Motor performances were significantly improved in the non-RBD group compared to the RBD group at the 1-year follow-up, and there was a trend toward a greater difference in the physical HRQoL compared with the 1-year follow-up. There were also marked improvements of axial symptom and physical HRQoL in the non-RBD group compared with the RBD group from baseline to 5 years after STN-DBS. CONCLUSION: Our study showed that RBD negatively affected the short- and long-term outcomes on motor performances, especially axial symptom and HRQoL after STN-DBS in PD patients.

Rapid Eye Movement Sleep Behavior Disorder and Other Rapid Eye Movement Parasomnias.

PURPOSE OF REVIEW: The discovery of rapid eye movement (REM) sleep and, in particular, REM sleep behavior disorder (RBD) have brought elusive nightmarish experiences to scientific scrutiny. This article summarizes a century of sleep research to examine the maladies of dreaming, their pathophysiologic significance, and management. RECENT FINDINGS: Under healthy physiologic conditions, REM sleep is characterized by vivid mentation combined with skeletal muscle paralysis. The loss of REM sleep atonia in RBD results in vivid, potentially injurious dream enactment to patients and bed partners. RBD is common, affecting at least 1% of the population and is primarily caused by α-synuclein pathology of REM sleep-related brainstem neurons. The majority of patients with RBD ultimately develop a neurodegenerative syndrome such as Parkinson disease, dementia with Lewy bodies, or multiple system atrophy. Among patients with Parkinson disease, RBD predicts an aggressive disease course with rapid cognitive, motor, and autonomic decline. RBD is diagnosed by the presence of dream enactment episodes (either recorded or clinically recalled) and physiologic evidence of REM sleep without atonia demonstrated on polysomnography. Bedroom safety is of paramount importance in the management of RBD while pharmacokinetic options include melatonin or clonazepam. SUMMARY: The injurious dream enactment of RBD is common and treatable. It is a syndrome of α-synuclein pathology with most patients ultimately developing Parkinson disease, dementia with Lewy bodies, or a related disorder.

Overview of sleep disturbances and their management in Parkinson plus disorders.

Sleep disturbance is one of the commonly reported non-motor symptoms in patients with Parkinson's disease (PD) as well as in Parkinson plus disorders such as multiple system atrophy (MSA), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS). Although there is a wealth of literature on sleep disturbances in PD, the same is not robust on the Parkinson plus disorders. This article aims to comprehensively review the sleep disturbances in Parkinson plus disorders. The literature review was as per the guidelines of the preferred reporting items for systematic reviews and meta-analyses (PRISMA). We searched PubMed and MEDLINE till December 2019 using a combination of words - "Sleep disturbance" with additional search terms such as: "synucleinopathy", "tauopathy", "multiple system atrophy", "dementia with Lewy bodies", "progressive supranuclear palsy", and "corticobasal syndrome". A wide range of sleep disorders that include insomnia, rapid eye movement (REM) sleep behaviour disorder (RBD), periodic limb movement disorder, excessive daytime sleepiness, and sleep apneas, may complicate the course of the Parkinson plus disorders. Pathophysiology of these sleep disorders remains elusive, thus making targeted pharmacotherapy challenging. We describe the cardinal features and the management options of these sleep disorders in the context of Parkinson plus disorders.

The Impact of Deep Brain Stimulation on Sleep in Parkinson's Disease: An update.

BACKGROUND: Parkinson's disease (PD) can have a significant impact on sleep. Deep brain stimulation (DBS) is an effective treatment for motor features of PD, but less is understood about the impact DBS may have on sleep architecture and various sleep issues commonly seen in PD. OBJECTIVE: To review the impact of DBS on various sleep issues in PD. METHODS: We reviewed the literature regarding the impact of DBS on sleep patterns, nocturnal motor and non-motor symptoms, and sleep disorders in PD. RESULTS: Objective sleep measures on polysomnography (PSG), including sleep latency and wake after sleep onset improve after subthalamic nucleus (STN) and globus pallidus interna (GPi) DBS. Subjective sleep measures, nocturnal motor symptoms, and some non-motor symptoms (nocturia) also may improve. Current evidence suggests STN DBS has no impact on Rapid Eye Movement Behavior Disorder (RBD), while STN DBS may improve symptoms of Restless Legs Syndrome (RLS). There are no studies that have evaluated the impact of GPi DBS on RBD, while it is unclear if GPi has an effect on RLS in PD. CONCLUSION: DBS therapy at either site appears to improve objective and subjective sleep parameters in patients with PD. Most likely, the improvement of motor and some non-motor nocturnal symptoms leads to an increase in total sleep time by up to an hour, as well as reduction of sleep fragmentation. DBS most likely has no impact on RBD, while there is evidence that STN DBS appears to help reduce RLS severity. Further studies are needed.

Update on nonpharmacological interventions in parasomnias.

Parasomnias are abnormal behaviors that occur during sleep and can be associated, in particular during adulthood, with impaired sleep quality, daytime dysfunction, and occasionally with violent and harmful nocturnal behaviors. In these cases, therapies are often considered. Longterm pharmacological treatments are not always well tolerated and often have limited efficacy. Therefore, behavioral approaches remain an important treatment option for several types of parasomnias. However, the evidence-based approaches are limited. In the current review, we highlight results from various nonpharmacological techniques on different types of parasomnias and provide a glimpse into the future of nonpharmacological treatments in this field.

Trauma-Associated Sleep Disorder: A Posttraumatic Stress/REM Sleep Behavior Disorder Mash-Up?

ABSTRACT: Trauma-associated sleep disorder (TASD) is a parasomnia sharing characteristics of post-traumatic stress disorder (PTSD) and REM sleep behavior disorder (RBD) including dream-enactment behavior (DEB). Here we report REM sleep without atonia (RSWA) and other neurological features in a patient with complex vocal and motor DEB following traumatic combat military exposure. Post-discharge, his wife observed frequent yelling and jerking during sleep with dream mentation reminiscent of traumatic military experiences. He was initially diagnosed with PTSD. Polysomnography demonstrated RSWA and severe obstructive sleep apnea treated with nasal continuous positive airway pressure (CPAP). Dream-enactment behavior severity and frequency was reduced, but still persisted despite nasal CPAP and sequential fluoxetine, escitalopram, prazosin, and melatonin trials. Our case demonstrated overlapping clinical features of PTSD and RBD with polysomnography features of RSWA supportive of idiopathic RBD but no "soft signs" suggesting underlying synucleinopathy. Longitudinal follow-up of larger case series must clarify whether TASD consistently manifests REM sleep atonia loss and determine the phenoconversion risk for synucleinopathy neurodegeneration. COMMENTARY: A commentary on this article appears in this issue on page 181.

The effect of light exposure on insomnia and nocturnal movement in Parkinson's disease: an open label, retrospective, longitudinal study.

Insomnia, hypersomnia and REM Sleep Behavior Disorder (RSBD) during sleep are major problems for patients suffering from Parkinson's disease (PD) but they are also used to predict its onset. While these secondary symptoms detract from the quality of life in PD patients, few treatment options are available due to limited efficacy or risk of complicating the treatment regimen. Light therapy (LT) has been suggested as a strategy for sleep disorders but it has only been implemented recently for use in PD. An open label, retrospective study was undertaken where PD patients had been undergoing LT, using polychromatic light, for four months to 15 years prior. It was found that 1 h exposure to light, just prior to retiring, significantly improved insomnia and reduced RSBD in as little as one month after commencing LT. In addition, the improvement was maintained as long as LT was continued over a four to six year period. The efficacy of LT in alleviating these sleep related conditions was not compromised by time since diagnosis or age of the patient. These results intimate the value of long term application of non-invasive techniques such as LT for treating sleep disorders in PD and justify further controlled trials on the long term efficacy of LT.