Flight to insight: maximizing the potential of Drosophila models of C9orf72-FTD

Advancements in understanding the pathogenesis of C9orf72-associated frontotemporal dementia (C9orf72-FTD) have highlighted the role of repeat-associated non-ATG (RAN) translation and dipeptide repeat proteins (DPRs), with Drosophila melanogaster models providing valuable insights. While studies have primarily focused on RAN translation and DPR toxicity, emerging areas of investigation in fly models have expanded to neuronal dysfunction, autophagy impairment, and synaptic dysfunction, providing potential directions for new therapeutic targets and mechanisms of neurodegeneration. Despite this progress, there are still significant gaps in Drosophila models of C9orf72-FTD, namely in the areas of metabolism and circadian rhythm. Metabolic dysregulation, particularly lipid metabolism, autophagy, and insulin signaling, has been implicated in disease progression with findings from animal models and human patients with C9orf72 repeat expansions. Moreover, circadian disruptions have been observed in C9of72-FTD, with alterations in rest-activity patterns and cellular circadian machinery, suggesting a potential role in disease pathophysiology. Drosophila models offer unique opportunities to explore these aspects of C9orf72-FTD and identify novel therapeutic targets aimed at mitigating neurodegeneration.

Detecting Abnormal Eye Movements in Patients with Neurodegenerative Diseases - Current Insights

This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's Disease (PD), atypical parkinsonism, and others, leveraging advancements in eye-tracking technology for enhanced diagnostic precision. We delve into the different classes of eye movements, their clinical assessment, and specific abnormalities manifesting in these diseases, highlighting the nuanced differences and shared patterns. For instance, AD and ADRD are characterized by increased saccadic latencies and instability in fixation, while PD features saccadic hypometria and mild smooth pursuit impairments. Atypical parkinsonism, notably Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS), presents with distinct ocular motor signatures such as vertical supranuclear gaze palsy and saccadic apraxia, respectively. Our review underscores the diagnostic value of eye movement analysis in differentiating between these disorders and also posits the existence of underlying common pathological mechanisms. We discuss how eye movements have potential as biomarkers for neurodegenerative diseases but also some of the existing limitations.

Predicting neurodegeneration from sleep related biofluid changes

Sleep-wake disturbances are common in neurodegenerative diseases and may occur years before the clinical diagnosis, potentially either representing an early stage of the disease itself or acting as a pathophysiological driver. Therefore, discovering biomarkers that identify individuals with sleep-wake disturbances who are at risk of developing neurodegenerative diseases will allow early diagnosis and intervention. Given the association between sleep and neurodegeneration, the most frequently analyzed fluid biomarkers in people with sleep-wake disturbances to date include those directly associated with neurodegeneration itself, such as neurofilament light chain, phosphorylated tau, amyloid-beta and alpha-synuclein. Abnormalities in these biomarkers in patients with sleep-wake disturbances are considered as evidence of an underlying neurodegenerative process. Levels of hormonal sleep-related biomarkers such as melatonin, cortisol and orexin are often abnormal in patients with clinical neurodegenerative diseases, but their relationships with the more standard neurodegenerative biomarkers remain unclear. Similarly, it is unclear whether other chronobiological/circadian biomarkers, such as disrupted clock gene expression, are causal factors or a consequence of neurodegeneration. Current data would suggest that a combination of fluid biomarkers may identify sleep-wake disturbances that are most predictive for the risk of developing neurodegenerative disease with more optimal sensitivity and specificity.

Sleep seasonality in alpha-synucleinopathies: A comparative study with non-neurological sleep disorder patients

INTRODUCTION

It is unknown if seasonal variation in daylight affects sleep in patients with alpha-synucleinopathies. Our objectives were to assess month of the year related changes in polysomnography (PSG) data in patients with Parkinson 's disease (PD), Lewy Body Dementia (LBD) and isolated REM sleep behavior disorder (iRBD).

METHODS

We collected PSG data from 64 PD, 30 LBD and 24 iRBD patients attending a sleep laboratory in Lisbon, Portugal, during 10 years. Each was classified according to the month of the year PSG was performed and compared with a control patient with sleep disorder, but no evidence of other neurological disorder, matched for sex, age group and PSG month. The influence of month in PSG data was assessed with mixed linear regression analysis.

RESULTS

In alpha-synucleinopathies, month showed significant interaction with N2 stage time and percentage (increase from December to April) and N3 time (peak in May). REM sleep percentage increased significantly from Spring to middle Summer. In the control group, there were significant interactions regarding Total Sleep Time and Sleep Efficiency (drop during wintertime), N2 time and REM % (increase in April and May) and Apnea-Hypopnea Index (AHI) (peak in June). There were significant associations between the term group*month and sleep efficiency and AHI, with larger monthly variation in the control group.

CONCLUSION

Seasonality had a larger impact in stage architecture in alpha-synucleinopathies, and in total sleep time, sleep efficiency and the severity of OSA in the control group. Different sleep dysfunction mechanisms could explain differences in seasonal variation.

Obstructive sleep apnea in Parkinson's disease: A prevalent, clinically relevant and treatable feature

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by motor and non-motor symptoms, including obstructive sleep apnea (OSA), a common comorbid sleep disorder. The prevalence of OSA in PD is high, and its impact on quality of life, accident risk, and limited treatment options underscores the need for vigilant monitoring and effective interventions. OSA is observed in 20-70% of PD patients, whereas the general population exhibits a lower prevalence ranging from 2 to 14%. These discrepancies in prevalence may be attributed to differences in demographic characteristics, sample sizes with selection bias, and variations in scoring systems for apnea and hypopnea events used across different studies. This review highlights the potential pathogenesis of comorbid OSA in PD and provides an overview of ongoing clinical trials investigating interventions for this condition. Several mechanisms have been implicated in the development of OSA in PD, including intermittent hypoxemia, sleep fragmentation, alterations in the glymphatic system homeostasis, upper airway obstruction, and inflammation. Given the adverse effects of PD comorbid OSA, early intervention measures are crucial. It is imperative to conduct longitudinal studies and clinical trials to elucidate the pathogenesis and develop novel and effective interventions for OSA in PD patients. These efforts aim to delay the progression of PD, enhance patients' quality of life, and alleviate the burden on society and families.

Scoring sleep in neurodegenerative diseases: A pilot study in the synucleinopathies

BACKGROUND

Neurodegenerative diseases often alter sleep architecture, complicating the application of the standard sleep scoring rules. There are no recommendations to overcome this problem. Our aim was to develop a scoring method that incorporates the stages previously applied in dementia with Lewy Bodies (DLB), anti-IgLON5 disease, and fatal insomnia, and to test it in patients with alpha-synucleinopathies.

METHODS

Video-polysomnographies (VPSG) of nine patients (DLB:3, Parkinson's disease (PD):3, and multiple system atrophy (MSA):3) selected for their difficulty in applying standard rules were scored independently by two authors, using additional Sleep/Wake stages. These included Abnormal Wake, Subwake, Undifferentiated NREM sleep (UNREM), Poorly structured N2 (P-S N2) and abnormal REM sleep including REM without atonia (RWA), REM without low-amplitude, mixed-frequency EEG activity (RWL) and REM without rapid eye movements (RWR).

RESULTS

Patients (4 females) had a median age of 74 (range 63-85). Six patients (all with PD or DLB) had abnormal EEG awake and Subwake stage. UNREM sleep was present in all patients, typically at sleep onset, and was the most common sleep stage in five. P-S N2 was recorded only in the three patients with MSA. Periods of normal and abnormal NREM coexisted in three patients. RWA was the predominant REM subtype, RWR occurred mainly in patients with MSA and RWL in those with DLB. Six patients had brief REM episodes into NREM sleep which we termed "Encapsulated RBD".

CONCLUSION

Our scoring system allows an accurate description of the complex sleep-wake changes in patients with alpha-synucleinopathies.

Low Specificity of Rapid Eye Movement Sleep Behavior Disorder Questionnaires: Need for Better Screening Methods

BACKGROUND

Correct diagnosis of rapid eye movement sleep behavior disorder (RBD) is critical due to its link to α-synucleinopathies and risk of injuries and requires video-polysomnography (V-PSG). Usefulness of screening questionnaires outside the context of validation studies is limited.

OBJECTIVE

The aim was to assess the performance of three validated RBD screening questionnaires compared with gold-standard V-PSG.

METHODS

In this bicentric prospective study, 400 consecutive subjects referred to a sleep center for the first time filled three RBD questionnaires (RBD Screening Questionnaire, RBD Single Question, and Innsbruck RBD Inventory) in random order before sleep experts' interview. Subjects positive for at least one questionnaire were invited to undergo V-PSG. Data from patients negative for all questionnaires undergoing V-PSG for other reasons were also evaluated. Questionnaire performances were compared to gold-standard V-PSG RBD diagnosis.

RESULTS

Three hundred ninety-nine patients (median age: 51 [interquartile range: 37-64] years, 54.9% men) participated. Two hundred thirty-eight (59.6%) were positive for at least one questionnaire, and RBD was diagnosed using V-PSG in 30 patients (7.5%). Questionnaire specificity was 48.1% to 67.4%, sensitivity 80% to 92%, accuracy 51% to 68.3%, negative predictive value 94.2% to 98%, and positive predictive value 14.1% to 20.7%, with no relevant differences in performances among the evaluated questionnaires.

CONCLUSIONS

RBD questionnaires have low specificity and low positive predictive value and should not be used as a standalone tool for the diagnosis of RBD. Further development of RBD screening methods is needed, particularly for upcoming neuroprotective trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dopaminergic Dysfunction Is More Symmetric in Dementia with Lewy Bodies Compared to Parkinson's Disease

BACKGROUND

The α-syn Origin site and Connectome model (SOC) proposes that α-synucleinopathies can be divided into two categories: the asymmetrical brain-first, and more symmetrical body-first Lewy body disease. We have hypothesized that most patients with dementia with Lewy bodies (DLB) belong to the body-first subtype, whereas patients with Parkinson's disease (PD) more often belong to the brain-first subtype.

OBJECTIVE

To compare asymmetry of striatal dopaminergic dysfunction in DLB and PD patients using [18F]-FE-PE2I positron emission tomography (PET).

METHODS

We analyzed [18F]-FE-PE2I PET data from 29 DLB patients and 76 PD patients who were identified retrospectively during a 5-year period at Dept. of Neurology, Aarhus University Hospital. Additionally, imaging data from 34 healthy controls was used for age-correction and visual comparison.

RESULTS

PD patients showed significantly more asymmetry in specific binding ratios between the most and least affected putamen (p < 0.0001) and caudate (p = 0.003) compared to DLB patients. PD patients also had more severe degeneration in the putamen compared to the caudate in comparison to DLB patients (p < 0.0001) who had a more universal pattern of striatal degeneration.

CONCLUSION

Patients with DLB show significantly more symmetric striatal degeneration on average compared to PD patients. These results support the hypothesis that DLB patients may be more likely to conform to the body-first subtype characterized by a symmetrical spread of pathology, whereas PD patients may be more likely to conform to the brain-first subtype with more lateralized initial propagation of pathology.

Sleep-Related Changes Prior to Cognitive Dysfunction

PURPOSE OF REVIEW

The aim of this review is to summarize the current evidence on the relationship between sleep and cognition and present available data reporting the impact that sleep alterations may have on cognitive functions.

RECENT FINDINGS

Research findings support the idea that sleep is involved in cognitive processes and that altered sleep homeostasis or circadian rhythms may lead to clinical and biochemical changes associated with cognitive impairment. Evidence is particularly solid for the association between specific sleep architecture and circadian alterations and Alzheimer's disease. Sleep changes, as early manifestations or possible risk factors for neurodegeneration and cognitive decline, may be appropriate targets for interventions aiming to reduce the likelihood of dementia.

Ethical Aspects of Prodromal Synucleinopathy Prognostic Counseling

Alpha-synucleinopathies can be identified in their prodromal phase, raising several ethical issues. In this review, we first provide definitions of prodromal α-synucleinopathies and discuss the importance of distinguishing between prodromes and risk factors. Next, we discuss the implications of a diagnosis of prodromal α-synucleinopathy and considerations regarding prognostic counseling in both clinical and research settings. We review available data on patient preferences regarding disclosure as well as providers' perspectives. We examine the pros and cons of disclosing a diagnosis of prodromal α-synucleinopathy, taking into consideration the differences between clinical and research settings. Asking about willingness to know in clinical and research settings and the shared decision-making process applied to prognostic counseling is discussed. Concerning research settings, ethical aspects regarding clinical trials are addressed. Availability of direct-to-consumer technologies will likely lead to novel contexts requiring prognostic counseling, and future neuroprotective or neuromodulating treatments may require further considerations on the timing, role, and importance of prognostic counseling. Recommendations on how to address ethical gaps should be a priority for patients, medical professional societies, and research workgroups. Ethical issues must be considered as an integral part of the overall clinical and research approach to prodromal synucleinopathies.

Sex differences in dementia with Lewy bodies: Focused review of available evidence and future directions

In this review, we summarize the current knowledge on sex differences in dementia with Lewy bodies (DLB) relating to epidemiology, clinical features, neuropathology, biomarkers, disease progression, and caregiving. While many studies show a higher DLB prevalence in men, this finding is inconsistent and varies by study approach. Visual hallucinations may be more common and occur earlier in women with DLB, whereas REM sleep behavior disorder may be more common and occur earlier in men. Several studies report a higher frequency of parkinsonism in men with DLB, while the frequency of fluctuations appears similar between sexes. Women tend to be older, have greater cognitive impairment at their initial visit, and are delayed in meeting DLB criteria compared to men. Women are also more likely to have Lewy body disease with co-existing AD-related pathology than so-called "pure" Lewy body disease, while men may present with either. Research is mixed regarding the impact of sex on DLB progression. Biomarker and treatment research assessing for sex differences is lacking. Women provide the majority of caregiving in DLB but how this affects the caregiving experience is uncertain. Gaining a better understanding of sex differences will be instrumental in aiding future development of sex-specific strategies in DLB for early diagnosis, care, and drug development.

Sleep architecture and sleep-disordered breathing in fatal insomnia

STUDY OBJECTIVES

Fatal insomnia (FI) is a rare prion disease severely affecting sleep architecture. Breathing during sleep has not been systematically assessed. Our aim was to characterize the sleep architecture, respiratory patterns, and neuropathologic findings in FI.

METHODS

Eleven consecutive FI patients (ten familial, one sporadic) were examined with video-polysomnography (vPSG) between 2002 and 2017. Wake/sleep stages and respiration were evaluated using a modified scoring system. Postmortem neuropathology was assessed in seven patients.

RESULTS

Median age at onset was 48 years and survival after vPSG was 1 year. All patients had different combinations of breathing disturbances including increased respiratory rate variability (RRV; n = 7), stridor (n = 9), central sleep apnea (CSA) (n = 5), hiccup (n = 6), catathrenia (n = 7), and other expiratory sounds (n = 10). RRV in NREM sleep correlated with ambiguous and solitary nuclei degeneration (r = 0.9, p = 0.008) and reduced survival (r = -0.7, p = 0.037). Two new stages, Subwake1 and Subwake2, present in all patients, were characterized. NREM sleep (conventional or undifferentiated) was identifiable in ten patients but reduced in duration in eight. REM sleep occurred in short segments in nine patients, and their reduced duration correlated with medullary raphe nuclei degeneration (r = -0.9, p = 0.005). Seven patients had REM without atonia. Three vPSG patterns were identified: agitated, with aperiodic, manipulative, and finalistic movements (n = 4); quiet-apneic, with CSA (n = 4); and quiet-non-apneic (n = 3).

CONCLUSIONS

FI patients show frequent breathing alterations, associated with respiratory nuclei damage, and, in addition to NREM sleep distortion, have severe impairment of REM sleep, related with raphe nuclei degeneration. Brainstem impairment is crucial in FI.

Dreaming in Parasomnias: REM Sleep Behavior Disorder as a Model

Sleep parasomnias have drawn the interest of sleep experts because they represent a valuable window to directly monitor dream activity and sleep mentation associated with nocturnal events. Indeed, parasomnias and their manifestations are helpful in investigating dream activity and features, overcoming methodological limits that affect dream study. Specifically, REM sleep Behavior Disorder (RBD) is a parasomnia characterized by enacted dream episodes during Rapid Eye Movements (REM) sleep, caused by the loss of physiological atonia. Patients suffering from RBD report a peculiar oneiric activity associated with motor episodes characterized by high Dream Recall Frequency (DRF) and vivid dreams. Additionally, isolated RBD (iRBD) represents a prodromal stage of neurodegeneration preceding the development of α-synucleinopathies. This narrative review aims to combine evidence describing dream activity in RBD and similarities and differences with other NREM parasomnias. Moreover, a special focus has been reserved for those conditions in which RBD is associated with α-synucleinopathies to clarify the potential role of dreams in neurodegenerative processes.

Sleep disturbances in Lewy body dementia: A systematic review

BACKGROUND

Lewy body dementia (LBD) refers to both dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD). Sleep disturbances are common in LBD, and can include poor sleep quality, excessive daytime sleepiness (EDS), and rapid eye movement behaviour disorder (RBD). Despite the high clinical prevalence of sleep disturbances in LBD, they are under-studied relative to other dementias. The aim of the present systematic review was to examine the nature of sleep disturbances in LBD, summarise the effect of treatment studies upon sleep, and highlight specific and necessary directions for future research.

METHODS

Published studies in English were located by searching PubMED and PSYCArticles databases (until 10 June 2022). The search protocol was pre-registered in PROSPERO (CRD42021293490) and performed in accordance with PRISMA guidelines.

RESULTS

Following full-text review, a final total of 70 articles were included. These included 20 studies focussing on subjective sleep, 14 on RBD, 8 on EDS, 7 on objective sleep, and 1 on circadian rhythms. The majority of the 18 treatment studies used pharmacological interventions (n = 12), had an open-label design (n = 8), and were of low-to-moderate quality. Most studies (n = 55) included only patients with DLB. Due to the heterogeneity of the studies, we reported a narrative synthesis without meta-analysis.

CONCLUSIONS

At least one form of sleep disturbance may be present in as many as 90% of people with LBD. Subjectively poor sleep quality, excessive daytime sleepiness, and RBD are more common and severe in LBD relative to other dementias.

Sleep stability in isolated rapid eye movement sleep behavior disorder, Parkinson's disease, and dementia with Lewy bodies

BACKGROUND

Non-REM sleep symptoms remain poorly understood in alpha-synucleinopathies.

AIMS

The aims of the study were to compare sleep stability and transitions, arousals, and sleep cycle structure between isolated rapid eye movement (REM) sleep behavior disorder (iRBD), Parkinson's disease (PD), and dementia with Lewy Bodies (DLB).

MATERIALS AND METHODS

Sleep transition and stability measures were assessed in one-night video-polysomnography records. Transition measures were the number of shifts between Wake and REM, Wake and NREM, and REM and NREM. Stability measures were the number of passages within the same sleep stage. We assessed arousals, the number/duration of sleep cycles (defined as a sequence of any NREM stage to REM), and the duration of N3 and REM sleep in each cycle. These variables were compared between two sets of groups (PD vs. DLB vs. iRBD and RDB+ vs. RBD-).

RESULTS

We assessed 54 PD, 24 DLB, and 21 iRBD patients (54 RBD+, 22 RBD-). There were no significant differences regarding sleep stability measures. Arousal indices in N1 and N2 stages were significantly higher in PD compared with iRBD. 24% of the sample did not have any sleep cycle. PD had significantly fewer cycles than iRBD. Differences became non-significant when adjusting for medication. There was no effect of group or time of night in REM or N3 duration. There were no significant differences between RBD+ and RBD-.

DISCUSSION

There were no significant differences in stability/transition measures. Arousals and disturbance in sleep cycling were higher in PD, but the difference was no longer significant after adjusting for medication.

CONCLUSION

Different alpha-synucleinopathies have a similar degree of non-REM sleep instability, but medication could worsen symptoms in PD.

Video-polysomnography procedures for diagnosis of rapid eye movement sleep behavior disorder (RBD) and the identification of its prodromal stages: guidelines from the International RBD Study Group

Video-polysomnography (v-PSG) is essential for diagnosing rapid eye movement (REM) sleep behavior disorder (RBD). Although there are current American Academy of Sleep Medicine standards to diagnose RBD, several aspects need to be addressed to achieve harmonization across sleep centers. Prodromal RBD is a stage in which symptoms and signs of evolving RBD are present, but do not yet meet established diagnostic criteria for RBD. However, the boundary between prodromal and definite RBD is still unclear. As a common effort of the Neurophysiology Working Group of the International RBD Study Group, this manuscript addresses the need for comprehensive and unambiguous v-PSG recommendations to diagnose RBD and identify prodromal RBD. These include: (1) standardized v-PSG technical settings; (2) specific considerations for REM sleep scoring; (3) harmonized methods for scoring REM sleep without atonia; (4) consistent methods to analyze video and audio recorded during v-PSGs and to classify movements and vocalizations; (5) clear v-PSG guidelines to diagnose RBD and identify prodromal RBD. Each section follows a common template: The current recommendations and methods are presented, their limitations are outlined, and new recommendations are described. Finally, future directions are presented. These v-PSG recommendations are intended for both practicing clinicians and researchers. Classification and quantification of motor events, RBD episodes, and vocalizations are however intended for research purposes only. These v-PSG guidelines will allow collection of homogeneous data, providing objective v-PSG measures and making future harmonized multicentric studies and clinical trials possible.

Associations Between Self-Reported Sleep Disturbances and Cognitive Impairment: A Population-Based Cross-Sectional Study

OBJECTIVE

Cognitive impairment is a rapidly growing global public health problem in China and worldwide. In the recent decades, emerging studies have explored the associations between sleep disturbances and cognitive impairment. However, the variety of the results imply us that further studies should be conducted for the associations.

METHODS

This is a cross-sectional study conducted between August and October 2018 in five cities in Hebei province, China. Subjects were 21,376 community residents. Cognitive impairment was screened by the Chinese version of the Mini-Mental State Examination (MMSE). Scales of Athens Insomnia Scale (AIS), Berlin Questionnaire (BQ), REM (rapid eye movement) Sleep Behavior Disorder Questionnaire (RBDQ-HK), Ullanlinna Narcolepsy Scale (CUNS), and Cambridge-Hopkins Restless Legs Syndrome Questionnaire (CH-RLSq) were used to access insomnia, sleep apnea, REM sleep behavior disorder, narcolepsy, and restless leg syndrome.

RESULTS

The mean ± SD (standard error) of MMSE, AIS, RBDQ-HK, and CUNS were 27.95 ± 4.79, 2.16 ± 3.39, 5.55 ± 7.75, and 3.76 ± 2.31, respectively. Among the participants, 10.6% and 1.5% of the participants were identified as having a high risk of sleep apnea and restless leg syndrome, respectively. The results of multiple linear regression showed that cognitive impairment was associated with insomnia (β = -0.037, p < 0.001) and narcolepsy (β = -0.023, p < 0.001). The association between sleep apnea (β = -0.002, p > 0.05), REM sleep behavior disorder (β = 0.006, p > 0.05), restless leg syndrome (β = -0.007, p > 0.05), and cognitive impairment were not supported. Other factors associated with cognitive impairment were gender, age, education level, married status, and region.

CONCLUSION

This study provides some epidemiological evidence for the association between sleep disturbances and cognitive impairment among community residents in central China. In this study, the associations between insomnia, narcolepsy, and cognitive impairment were identified, but the associations between sleep apnea, REM sleep behavior disorder, narcolepsy, restless leg syndrome, and cognitive impairment were not supported among community residents.

Sleep disturbance in movement disorders: insights, treatments and challenges

Sleep and circadian rhythm disturbances are central features of many movement disorders, exacerbating motor and non-motor symptoms and impairing quality of life. Understanding these disturbances to sleep is clinically important and may further our understanding of the underlying movement disorder. This review evaluates the current anatomical and neurochemical understanding of normal sleep and the recognised primary sleep disorders. In addition, we undertook a systematic review of the evidence for disruption to sleep across multiple movement disorders. Rapid eye movement sleep behaviour disorder has emerged as the most reliable prodromal biomarker for the alpha synucleinopathies, including Parkinson's disease and multiple system atrophy, often preceding motor symptom onset by several years. Abnormal sleep has also been described for many other movement disorders, but further evidence is needed to determine whether this is a primary or secondary phenotypic component of the underlying condition. Medication used in the treatment of motor symptoms also affects sleep and can aggravate or cause certain sleep disorders. Within the context of movement disorders, there is also some suggestion of a shared underlying mechanism for motor and sleep pathophysiology, with evidence implicating thalamic and brainstem structures and monoaminergic neurotransmission. This review highlights the need for an understanding of normal and abnormal sleep within the movement disorder clinic, an ability to screen for specific causes of poor sleep and to treat sleep disturbance to improve quality of life. Key sleep disorders also act as important biomarkers and have implications in diagnosis, prognosis and the development of future therapies.

Scoring of large muscle group movements during sleep: An International Restless Legs Syndrome Study Group (IRLSSG) position statement

There is a gap in the manuals for scoring sleep-related movements because of the absence of rules for scoring large movements. A taskforce of the International Restless Legs Syndrome Study Group elaborated rules that define the detection and quantification of movements involving large muscle groups. Consensus on each of the criteria in this paper was reached by testing the presence of consensus on a first proposal; if no consensus was achieved, the concerns were considered and used to modify the proposal. This process was iterated until consensus was reached. A preliminary analysis of the duration of movements involving large muscle groups was also carried out on data from two previous studies, which, however, used a visual analysis of video-polysomnographic recordings obtained from children or adults. Technical specifications and scoring rules were designed for the detection and quantification of large muscle group movements during sleep with a duration between 3 and 45 s in adults or 3 and 30 s in children, characterized by an increase in electromyographic activity and/or the occurrence of movement artifact in any combination of at least two recommended channels and not meeting the criteria for any other type of movement. Large muscle group movements are often accompanied by sleep stage changes, arousals, awakenings, and heart rate rises. The absence of clear and detailed rules defining them has likely impeded the development of studies that might disclose their clinical relevance; these new rules fill this gap.

Objective sleep data as predictors of cognitive decline in dementia with Lewy Bodies and Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB) prognosis depends on cognitive function evolution. Sleep disorders, as objectivated by polysomnography (PSG), are intimately connected with PD and DLB pathophysiology, but have seldomly been used to predict cognitive decline.

METHODS

20 DLB and 49 PD patients underwent one-night in-lab video-PSG. Sleep variables were defined, including REM sleep motor events, Tonic and phasic REM sleep muscular tone and RBD diagnosis. Cognitive state (assessed with the Global Deterioration Scale (GDS) was collected from case files for 6 months intervals, for a maximum period of 3.5 years or until death/drop-out.). The relation between PSG data at baseline and variation of GDS scores over time was tested with mixed linear regression analysis.

RESULTS

GDS scores were higher in DLB, than in PD. We confirmed significant cognitive decline in both disorders, but no significant differences in progression between them. There were no significant interactions between PSG data and GDS variation for the entire group and DLB separately. In PD patients, there was a significant interaction between RBD diagnosis and tonic excessive muscular tone and GDS increase.

CONCLUSION

Our data suggests that PSG data can be useful in predicting cognitive decline in PD but not in DLB patients. In PD patients, an RBD diagnosis is predictive of cognitive deterioration, confirming the notion that this non-motor symptom relates to a malignant sub-type. Tonic excessive muscular activity, but not other RBD features, had predictive value in this group, pointing to a specific relation with the disease pathophysiology.

Early Disruption of Cortical Sleep-Related Oscillations in a Mouse Model of Dementia With Lewy Bodies (DLB) Expressing Human Mutant (A30P) Alpha-Synuclein

Changes in sleep behavior and sleep-related cortical activity have been reported in conditions associated with abnormal alpha-synuclein (α-syn) expression, in particular Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Notably, changes can occur in patients years before the onset of cognitive decline. Sleep-related network oscillations play a key role in memory function, but how abnormal α-syn impacts the generation of such activity is currently unclear. To determine whether early changes in sleep-related network activity could also be observed, prior to any previously reported cognitive dysfunction, we used mice that over-express human mutant α-syn (A30P). Recordings in vivo were performed under urethane anesthesia in the medial prefrontal cortex (mPFC) and CA1 region of the hippocampus in young male (2.5 – 4 months old) A30P and age-matched wild type (WT) mice. We found that the slow oscillation (SO) < 1 Hz frequency was significantly faster in both the mPFC and hippocampus in A30P mice, and Up-state-associated fast oscillations at beta (20 – 30 Hz) and gamma (30 – 80 Hz) frequencies were delayed relative to the onset of the Up-state. Spindle (8 – 15 Hz) activity in the mPFC was also altered in A30P mice, as spindles were shorter in duration and had reduced density compared to WT. These changes demonstrate that dysregulation of sleep-related oscillations occurs in young A30P mice long before the onset of cognitive dysfunction. Our data suggest that, as seen in patients, changes in sleep-related oscillations are an early consequence of abnormal α-syn aggregation in A30P mice.

NREM sleep arousal-related disorders reflect cognitive impairment in Parkinson's disease

BACKGROUND

Sleep disorders and cognitive impairment are frequently reported in Parkinson's disease (PD) as non-motor disabling symptoms. While it is known that REM sleep Behaviour Disorder (RBD) in PD is associated with motor and cognitive decline, little is known about the neurobiological significance of NREM sleep arousal-related disorders.

OBJECTIVES

to evaluate the cognitive and clinical correlates of arousal-related disorders in PD.

METHODS

Clinical data and video-polysomnography were analysed from one hundred-seventy consecutive subjects with PD. Based on the neuropsychological assessment, the subjects were divided into three groups: no cognitive impairment (PD; n = 58), mild cognitive impairment (PD-MCI; n = 58) and overt dementia (PDD; n = 54).

RESULTS

Arousal-related disorders by history were reported in 32.9% of the subjects: 10.3% PD, 31.6% PD-MCI and 59.3% PDD (p = 0.001). Video-PSG captured arousal-related disorders in 1.7% PD, 21.2% MCI-PD and 35.6% PDD (p = 0.001). Arousal-related disorders and RBD were recorded in the same night in 7.7% PD, 9.8% MCI-PD and 15.6% PDD (p = 0.04). Patients with arousal-related disorders captured at V-PSG have a longer disease duration (p = 0.003), higher UPDRS score (p = 0.039), longer duration of treatment with levodopa (p = 0.017) and dopamine agonists (p = 0.018), worse H&Y staging (p = 0.001), lower MMSE score (p = 0.019) and more frequently hallucinations (p = 0.004). In multivariate analysis, cognitive impairment significantly increases the risk of arousal-related disorders (OR 3.387-95% CI 1.395-8.220, p = 0.007).

CONCLUSION

Arousal-related disorders appear to be a marker of cognitive decline in PD. Recognizing arousal-related disorders should make clinicians aware of a possible cognitive decline in PD and eventually modify the therapeutic approach.

Characterization of the sleep disorder of anti-IgLON5 disease

STUDY OBJECTIVE

To characterize the sleep disorder of anti-IgLON5 disease.

METHODS

We reviewed 27 video-polysomnographies (V-PSG), 6 multiple sleep latency tests (MSLT), 2 videsomnoscopies with dexmedetomidine, and 10 actigraphies recorded during the disease course of five patients. Due to severe sleep architecture abnormalities, we used a novel modified sleep scoring system combining conventional stages with a descriptive approach in which two additional stages were identified: undifferentiated-NREM (UN-NREM) and poorly structured N2 (P-SN2) sleep that were characterized by abnormal motor activation and absence or sparse elements of conventional NREM sleep.

RESULTS

Sleep-related vocalizations, movements, behaviors, and respiratory abnormalities were reported by bed-partners. In all patients, NREM sleep onset and sleep reentering after an awakening occurred as UN-NREM (median: 29.8% of total sleep time [TST]) and P-SN2 sleep (14.5% TST) associated with vocalizations and simple and quasi-purposeful movements. Sleep initiation was normalized in one patient with a high dose of steroids, but NREM sleep abnormalities reappeared in subsequent V-PSG. In all patients, if sleep continued uninterrupted, there was a progressive normalization with normal N2 (11.7% TST) and N3 (22.3% TST) sleep but stridor and obstructive apnea emerged. REM sleep behavior disorder (RBD) occurred in four patients. Sleep initiation was also altered in MSLT and dexmedetomidine-induced sleep. Actigraphy showed a 10-fold increase of nocturnal activity compared with controls. Sleep abnormalities remained stable during the disease.

CONCLUSIONS

The sleep disorder of anti-IgLON5 disease presents as a complex sleep pattern characterized by abnormal sleep initiation with undifferentiated NREM sleep, RBD, periods of normal NREM sleep, stridor, and obstructive apnea.

Sleep disorders in anti-NMDAR encephalitis

Objective

To describe the sleep disorders in anti–NMDA receptor encephalitis (anti-NMDARe).

Methods

Patients recovering from anti-NMDARe were invited to participate in a prospective observational single-center study including comprehensive clinical, video-polysomnography (V-PSG) sleep assessment, and neuropsychological evaluation. Age- and sex-matched healthy participants served as controls.

Results

Eighteen patients (89% female, median age 26 years, interquartile range [IQR] 21–29 years) and 21 controls (81% female, median age 23 years, IQR 18–26 years) were included. In the acute stage, 16 (89%) patients reported insomnia and 2 hypersomnia; nightmares occurred in 7. After the acute stage, 14 (78%) had hypersomnia. At study admission (median 183 days after disease onset, IQR 110–242 days), 8 patients still had hypersomnia, 1 had insomnia, and 9 had normal sleep duration. Patients had more daytime sleepiness than controls (higher Barcelona Sleepiness Index, p = 0.02, and Epworth Sleepiness Score, p = 0.04). On V-PSG, sleep efficiency was similar in both groups, but patients more frequently had multiple and longer confusional arousals in non-REM (NREM) sleep (videos provided). In addition, 13 (72%) patients had cognitive deficits; 12 (67%) had psychological, social, or occupational disability; and 33% had depression or mania. Compared with controls, patients had a higher body mass index (median 23.5 [IQR 22.3–30.2] vs 20.5 [19.1–21.1] kg/m2; p = 0.007). Between disease onset and last follow-up, 14 (78%) patients developed hyperphagia, and 6 (33%) developed hypersexuality (2 requiring hospitalization), all associated with sleep dysfunction.

Conclusions

Sleep disturbances are frequent in anti-NMDARe. They show a temporal pattern (predominantly insomnia at onset; hypersomnia during recovery), are associated with behavioral and cognitive changes, and can occur with confusional arousals during NREM sleep.