Isolated rapid eye movement sleep behaviour disorder (iRBD) in the Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) Sleep Study: protocol and baseline characteristics

Isolated rapid eye movement (REM) sleep behaviour disorder (iRBD) is a sleep disorder that is characterised by dream enactment episodes during REM sleep. It is the strongest known predictor of α-synuclein-related neurodegenerative disease (αNDD), such that >80% of people with iRBD will eventually develop Parkinson's disease, dementia with Lewy bodies, or multiple system atrophy in later life. More research is needed to understand the trajectory of phenoconversion to each αNDD. Only five 'gold standard' prevalence studies of iRBD in older adults have been undertaken previously, with estimates ranging from 0.74% to 2.01%. The diagnostic recommendations for video-polysomnography (vPSG) to confirm iRBD makes prevalence studies challenging, as vPSG is often unavailable to large cohorts. In Australia, there have been no iRBD prevalence studies, and little is known about the cognitive and motor profiles of Australian people with iRBD. The Island Study Linking Ageing and Neurodegenerative Disease (ISLAND) Sleep Study will investigate the prevalence of iRBD in Tasmania, an island state of Australia, using validated questionnaires and home-based vPSG. It will also explore several cognitive, motor, olfactory, autonomic, visual, tactile, and sleep profiles in people with iRBD to better understand which characteristics influence the progression of iRBD to αNDD. This paper details the ISLAND Sleep Study protocol and presents preliminary baseline results.

The Motor Dysfunction Seen in Isolated REM Sleep Behavior Disorder

BACKGROUND

Isolated Rapid Eye Movement (REM) sleep Behavior Disorder (iRBD) requires quantitative tools to detect incipient Parkinson's disease (PD).

METHODS

A motor battery was designed and compared with the Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III) in people with iRBD and controls. This included two keyboard-based tests (BRadykinesia Akinesia INcoordination tap test and Distal Finger Tapping) and two dual tasking tests (walking and finger tapping).

RESULTS

We included 33 iRBD patients and 29 controls. The iRBD group performed both keyboard-based tapping tests more slowly (P < 0.001, P = 0.020) and less rhythmically (P < 0.001, P = 0.006) than controls. Unlike controls, the iRBD group increased their walking duration (P < 0.001) and had a smaller amplitude (P = 0.001) and slower (P = 0.007) finger tapping with dual task. The combination of the most salient motor markers showed 90.3% sensitivity for 89.3% specificity (area under the ROC curve [AUC], 0.94), which was higher than the MDS-UPDRS-III (minus action tremor) (69.7% sensitivity, 72.4% specificity; AUC, 0.81) for detecting motor dysfunction.

CONCLUSION

Speed, rhythm, and dual task motor deterioration might be accurate indicators of incipient PD in iRBD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Sleep Disturbances in Autoimmune Neurological Diseases

PURPOSE OF REVIEW

To summarize the current evidence on the associations between autoimmune neurological diseases (e.g., multiple sclerosis, myasthenia gravis) and sleep disturbances (e.g., insomnia, parasomnias), as well as to review the main characteristics of sleep disorders with an immune-related pathophysiology (e.g., narcolepsy, anti-IgLON5 disease).

RECENT FINDINGS

An immune-mediated damage of the areas in the central nervous system that control sleep and wake functions (e.g., hypothalamus, brainstem) can lead to sleep disorders and sleep symptoms. Sleep disturbances are the reason to seek for medical attention in certain neuroimmunological conditions (e.g., narcolepsy, anti-IgLON5 disease) where sleep-related alterations are the main clinical feature. The assessment of sleep-related symptomatology and disorders should be included in the routine evaluation of patients with autoimmune neurological diseases. Clinicians should be aware of the typical clinical presentation of certain neuroimmunological disorders mainly affecting sleep.

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.

Sleep in Gerstmann-Straüssler-Scheinker disease

BACKGROUND

Gerstmann-Sträussler-Scheinker (GSS) is a rare prion disease with heterogeneous clinical presentation. Although sleep-related abnormalities are prominent and well-known in other prion diseases such as fatal familial insomnia and Creutzfeldt-Jakob disease, information on sleep is limited in GSS.

METHODS

We evaluated sleep in three genetically confirmed GSS cases using clinical history, sleep scales and video-polysomnography. In addition, patients underwent neurological assessment, neurological scales, neuropsychological testing, lumbar puncture, brain MRI and brain ¹⁸F-FDG-PET.

RESULTS

Two patients reported sleep maintenance insomnia attributed to leg stiffness and back pain while the remaining patient did not report sleep problems. Video-polysomnography showed normal sleep staging in all of them. Findings such as reduced sleep efficiency in two patients, a confusional arousal in one patient, obstructive apneas in one patient, and periodic legs movements in sleep in two patients were observed.

CONCLUSIONS

In contrast to fatal familial insomnia, the normal sleep staging in GSS may suggest dissimilar involvement of the neuronal structures that regulate sleep. We found non-specific sleep alterations in GSS such as obstructive apneas and periodic leg movements in sleep which are of unknown origin and of uncertain clinical relevance. Studies including a larger number of patients, serial sleep evaluations and incorporating neuropathological assessment will further help to understand sleep in GSS.

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.

Nocturnal visual hallucinations in patients with disorders of arousal: a novel behavioral and EEG pattern

AIM

To investigate clinical and video-polysomnography (VPSG) findings of hallucinatory experiences in patients suffering from disorders of arousal (DOA) in the absence of other pathologies.

METHODS

The authors retrospectively reviewed the records of 370 adults with DOA. Thirty (8.1%) patients concomitantly reported complex nocturnal visual hallucinations. VPSG recordings were scrutinized, and motor behavioral and electroencephalogram (EEG) patterns were classified according to previous descriptions of DOA.

RESULTS

Thirty DOA patients reported seeing images of objects, people, and animals; either distorted, static, or mobile. The images disappeared with increased illumination in 80% of patients, and 23.3% reported preceding dream imagery. In addition to the classical DOA patterns on VPSG, a distinct pattern of behavioral and EEG manifestation associated with complex hallucinatory episodes was identified in 16 (53.3%) DOA patients. This consisted of low-voltage mixed-frequency EEG activity before eye opening that persisted while patients were observed staring or visually tracking before the onset of motor behavior.

CONCLUSION

A novel, distinct behavioral and EEG pattern in patients with DOA and history of reported complex nocturnal visual hallucinations was identified. This may represent a unique phenotype of dissociation between sleep states that merits further investigation.

Understanding and approaching excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is a public health issue. However, it remains largely undervalued, scarcely diagnosed, and poorly supported. Variations in the definition of EDS and limitations in clinical assessment lead to difficulties in its epidemiological study, but the relevance of this symptom from a socioeconomic perspective is inarguable. EDS might be a consequence of several behavioural issues leading to insufficient or disrupted sleep, as well as a consequence of sleep disorders including sleep apnoea syndrome, circadian disorders, central hypersomnolence disorders (narcolepsy and idiopathic hypersomnia), other medical or psychiatric conditions, or medications. Furthermore, EDS can have implications for health as it is thought to act as a risk factor for other conditions, such as cardiovascular and neurodegenerative disorders. Because of the heterogeneous causes of EDS and the complexity of its pathophysiology, management will largely depend on the cause, with the final aim of making treatment specific to the individual using precision medicine and personalised medicine.

What, when and how should the information about neurodegenerative disease risk in iRBD be communicated?

Background

Idiopathic/isolated REM sleep behaviour disorder (iRBD) is characterised by vivid dreams with ‘acting-out’ behaviours due to REM sleep muscle atonia. It is associated with a risk of Parkinson’s disease (PD) and other synucleinopathies. There is uncertainty about what should be disclosed to iRBD patients in terms of future risk1.

Methods

A survey was administered to patients with iRBD and participating in the PREDICT-PD study. They were invited to complete a 9-question survey exploring the information they would like to receive about the potential future implications of having iRBD.

Results

We interviewed 31 patients (28 males, 70yo, SD 8.7y) with iRBD (mean 8.7-year disease duration, SD 6.4). A third had not received any information about the link of iRBD with other conditions by health- care professionals. More than half (61%) had searched for that information online. Most patients (87%) wanted to receive prognostic information to help them make informed decisions about their future. The preferred time for this was when a diagnosis of iRBD was made rather than when parkinsonism starts (61% vs 7%). Most wanted this information to come from their iRBD specialist (93%).

Conclusions

Patients with iRBD mostly wished to receive information regarding the potential future impli- cations of having iRBD when the diagnosis of iRBD is made. Taking account of patients’ preferences is relevant to decide what, when and how to disclose prognostic information to patients with iRBD.

Cotard parasomnia: le délire de negation that occur during the sleep-wake dissociation?

None

Unpleasant dreamlike mentation can occur during non-rapid eye movement parasomnias, leading to associated panic attacks. The mentations are rarely remembered and are likely underreported. However, they may lead to significant personal distress and, if not addressed, may contribute to poorer clinical outcomes. Cotard le délire de negation are very rare nihilistic delusions, historically described with psychotic disorders. Their association with a variety of neurologic disorders, including migraine and cluster-headache, has also been reported. Here we present three cases of Cotard parasomnia during which distinct states of consciousness defined by nihilistic ideation occurred. Patients described believing they are dead or dying, while unable to perceive or experience their bodies in whole, or in part, as their own. A source analysis of the electroencephalographic fingerprint of these mentations suggests right-hemispheric hypoactivity subsequent to confusional arousals. Mechanistically, an aberrant activation of two major intrinsic brain networks of wakefulness, the salience network and the default mode network, is argued.

[Sleep-related movement and behavioural disorders in adults]

Sleep-related movement and behaviour disorders may have an impact on sleep quality and lead to daytime symptoms. These groups of conditions include diseases such as restless legs syndrome, periodic leg movements, and REM and NREM parasomnias. The knowledge of their clinical features and management is of utmost importance for the neurologist and sleep specialist. Frequently, these patients are referred to such specialists and it is relevant to know that certain sleep disorders may be associated with other neurological conditions.

Impact of the novel coronavirus (COVID-19) pandemic on sleep

Background

The COVID-19 pandemic has led to significant changes in daily routines and lifestyle worldwide and mental health issues have emerged as a consequence. We aimed to assess the presence of sleep disturbances during the lockdown in the general population.

Methods

Cross-sectional, online survey-based study on adults living through the COVID-19 pandemic. The questionnaire included demographics and specific questions assessing the impact of the pandemic/lockdown on sleep, daytime functioning and mental health in the general population. Identification of sleep pattern changes and specific sleep-related symptoms was the primary outcome, and secondary outcomes involved identifying sleep disturbances for predefined cohorts (participants reporting impact on mental health, self-isolation, keyworker status, suspected COVID-19 or ongoing COVID-19 symptoms).

Results

In total, 843 participants were included in the analysis. The majority were female (67.4%), middle aged [52 years (40–63 years)], white (92.2%) and overweight to obese [BMI 29.4 kg/m² (24.1–35.5 kg/m²)]; 69.4% reported a change in their sleep pattern, less than half (44.7%) had refreshing sleep, and 45.6% were sleepier than before the lockdown; 33.9% had to self-isolate, 65.2% reported an impact on their mental health and 25.9% were drinking more alcohol during the lockdown. More frequently reported observations specific to sleep were ‘disrupted sleep’ (42.3%), ‘falling asleep unintentionally’ (35.2%), ‘difficulties falling’/‘staying asleep’ (30.9% and 30.8%, respectively) and ‘later bedtimes’ (30.0%). Respondents with suspected COVID-19 had more nightmares and abnormal sleep rhythms. An impact on mental health was strongly associated with sleep-related alterations.

Conclusions

Sleep disturbances have affected a substantial proportion of the general population during the COVID-19 pandemic lockdown. These are significantly associated with a self-assessed impact on mental health, but may also be related to suspected COVID-19 status, changes in habits and self-isolation.

Narrative review of sleep and stroke

Sleep disorders, such as sleep-disordered breathing (SDB), insomnia or restless legs syndrome (RLS), are common in the general population and after stroke. In some cases, sleep disturbances are pre-existing, but can also appear de novo as a direct consequence of brain damage or due to stroke-related complications. Furthermore, some sleep conditions may act as a risk factor of stroke. This review explores the available evidence of the two-way relationship between sleep and stroke. Cardiovascular physiological changes during sleep are described, as well as the evidence on the relationship between stroke and sleep duration, SDB, RLS, insomnia, excessive daytime sleepiness (EDS), and circadian rhythm alterations. Potential changes on sleep architecture, and the links that may exist between sleep and functional outcomes after stroke are also discussed. Importantly, sleep-related disturbances may be associated with worse stroke recovery outcomes and increased cerebrovascular morbidity. It is therefore relevant that the bidirectional association between stroke and sleep is taken into consideration by clinicians taking care of these patients. Future research may focus on this mutual relationship for a better understanding of the impact of stroke on sleep, the importance of sleep in stroke incidence and recovery, and have further evidence on treatment strategies that may improve functional outcome after stroke.

Cotard's Parasomnia: Le Délire de Negation that occur during the Sleep-Wake Dissociation?

Unpleasant dreamlike mentation can occur during NREM parasomnias, leading to associated panic attacks. The mentations are rarely remembered, and are likely underreported. However, they may lead to significant personal distress, and if not addressed, may contribute to poorer clinical outcomes. Cotard's 'Le Délire de Negation', are very rare nihilistic delusions, historically described with psychotic disorders. Their association with variety of neurologic disorders, including migraine and cluster-headache, has also been reported. Here we present three cases of Cotard's parasomnia during which distinct states of consciousness defined by nihilistic ideation are reported. Patients described believing to be dead or dying, whilst unable to perceive or experience their bodies in whole, or in part, as their own. The source analysis of electroencephalographic fingerprint of these mentations suggests right hemispheric hypoactivity subsequent to confusional arousals. Mechanistically, an aberrant activation of two major intrinsic brain networks of wakefulness, the salience and the default-mode-network is argued.

[Sleep-disordered breathing as a consequence of vagus nerve stimulation]

INTRODUCTION

Vagus nerve stimulation (VNS) is indicated in cases of refractory epilepsy. Its side effects are frequently minor, however, breathing disturbances during sleep have been previously reported.

CASE REPORTS

Our three cases are representative of sleep-disordered breathing that occurred as a consequence of VNS activity in patients with refractory epilepsy. Sleep apnoea was observed in two patients and stridor in one patient.

CONCLUSIONS

Given the high prevalence of sleep apnoea-hypopnoea syndrome in patients with refractory epilepsy, implantation of VNS should be ideally preceded by an assessment of the breathing during sleep. Furthermore, sleep-disordered breathing should be considered as a rare complication of VNS, and sleep apnoea should be investigated alongside data regarding VNS firing.

Vagus nerve stimulation for drug-resistant epilepsy

Vagus nerve stimulation (VNS) is a neuromodulatory therapeutic option for drug-resistant epilepsy. In randomised controlled trials, VNS implantation has resulted in over 50% reduction in seizure frequency in 26%-40% of patients within 1 year. Long-term uncontrolled studies suggest better responses to VNS over time; however, the assessment of other potential predictive factors has led to contradictory results. Although initially designed for managing focal seizures, its use has been extended to other forms of drug-resistant epilepsy. In this review, we discuss the evidence supporting the use of VNS, its impact on seizure frequency and quality of life, and common adverse effects of this therapy. We also include practical guidance for the approach to and the management of patients with VNS in situ.

TP3-7 Sleep-disordered breathing as a consequence of vagal nerve stimulation

Objectives

Vagal nerve stimulation (VNS) is a neuromodulatory therapy indicated in drug-resistant epilepsy (DRE). Its side effects are frequently minor, however, sleep-disordered breathing (SDB) has been previously reported.1Obstructive sleep apnoea (OSA) is highly prevalent in individuals with refractory epilepsy, and may be a cause of poor control of seizures.2

Methods

Three DRE patients with active VNS underwent a video-polysomnography with 21-channel montage electroencephalography in our centre.

Results

First and second patients showed OSA at the time of VNS activation. In the first patient, the apnoeic-induced arousals triggered VNS auto-firing and consequent respiratory events, perpetuating the SDB. The third patient had episodes of stridor, and an increased respiratory rate, coinciding with VNS activation. Our cases are representative of different forms of SDB that occurred as a consequence of the switch-on phase of the VNS device.

Conclusions

Sleep-related breathing disturbances should be considered before VNS implantation, and should be routinely assessed after having started the therapy. Changes in stimulation parameters, and positive airway pressure therapy, may be required to treat the SDB.

Clinical update on central hypersomnias

The central hypersomnias encompass a range of conditions causing persisting or intermittent excessive daytime sleepiness (EDS). These conditions therefore present not infrequently in general clinical sleep practice, and remain in the differential for patients presenting with sleepiness. Our understanding of the pathophysiology, diagnosis and management of these conditions has progressed significantly over recent years, and in this article we review this group of disorders, focussing in particular on recent changes in classification and diagnosis, pathophysiological advances, and novel treatment options.