Differences in sleep in patients with Parkinson's disease

Clinical neurophysiology of REM parasomnias: Diagnostic aspects and insights into pathophysiology

Parasomnias are due to a transient unstable state dissociation during entry into sleep, within sleep, or during arousal from sleep, and manifest with abnormal sleep related behaviors, perceptions, emotions, dreams, and autonomic nervous system activity. Rapid eye movement (REM) parasomnias include REM sleep behavior disorder (RBD), isolated recurrent sleep paralysis and nightmare disorder. Neurophysiology is key for diagnosing these disorders and provides insights into their pathophysiology. RBD is very well characterized from a neurophysiological point of view, also thank to the fact that polysomnography is needed for the diagnosis. Diagnostic criteria are provided by the American Academy of Sleep Medicine and video-polysomnography guidelines for the diagnosis by the International REM Sleep Behavior Disorder Study Group. Differences between the two sets of criteria are presented and discussed. Availability of polysomnography in RBD provides data on sleep electroencephalography (EEG), electrooculography (EOG) and electromyography (EMG). Sleep EEG in RBD shows e.g. changes in delta and theta power, in sleep spindles and K complexes. EMG during REM sleep is essential for RBD diagnosis and is an important neurodegeneration biomarker. RBD patients present alterations also in wake EEG, autonomic function, evoked potentials, and transcranial magnetic stimulation. Clinical neurophysiological data on recurrent isolated sleep paralysis and nightmare disorder are scant. The few available data provide insights into the pathophysiology of these disorders, demonstrating a state dissociation in recurrent isolated sleep paralysis and suggesting alterations in sleep macro- and microstructure as well as autonomic changes in nightmare disorder.

Rapid eye movement sleep behaviour disorder: Past, present, and future

This manuscript presents an overview of REM sleep behaviour disorder (RBD) with a special focus on European contributions. After an introduction examining the history of the disorder, we address the pathophysiological and clinical aspects, as well as the diagnostic issues. Further, implications of RBD diagnosis and biomarkers are discussed. Contributions of European researchers to this field are highlighted.

Importance of the locus coeruleus-norepinephrine system in sleep-wake regulation: implications for aging and Alzheimer’s disease

Five decades ago, seminal studies positioned the brainstem locus coeruleus (LC) norepinephrine (NE) system as a key substrate for the regulation of wakefulness and sleep, and this picture has recently been elaborated thanks to methodological advances in the precise investigation and experimental modulation of LC structure and functions. This review presents and discusses findings that support the major role of the LC-NE system at different levels of sleep-wake organization, ranging from its involvement in the overall architecture of the sleep-wake cycle to its associations with sleep microstructure, while accounting for the intricate neuroanatomy surrounding the LC. Given the particular position held by the LC-NE system by being at the intersection of sleep-wake dysregulation and initial pathophysiological processes of Alzheimer's disease (AD), we conclude by examining emerging opportunities to investigate LC-NE mediated relationships between sleep-wake alteration and AD in human aging. We further propose several research perspectives that could support the LC-NE system as a promising target for the identification of at-risk individuals in the preclinical stages of AD, and for the development of novel preventive interventions.

Basal Ganglia Local Field Potentials as a Potential Biomarker for Sleep Disturbance in Parkinson's Disease

Sleep disturbances, specifically decreases in total sleep time and sleep efficiency as well as increased sleep onset latency and wakefulness after sleep onset, are highly prevalent in patients with Parkinson's disease (PD). Impairment of sleep significantly and adversely impacts several comorbidities in this patient population, including cognition, mood, and quality of life. Sleep disturbances and other non-motor symptoms of PD have come to the fore as the effectiveness of advanced therapies such as deep brain stimulation (DBS) optimally manage the motor symptoms. Although some studies have suggested that DBS provides benefit for sleep disturbances in PD, the mechanisms by which this might occur, as well as the optimal stimulation parameters for treating sleep dysfunction, remain unknown. In patients treated with DBS, electrophysiologic recording from the stimulating electrode, in the form of local field potentials (LFPs), has led to the identification of several findings associated with both motor and non-motor symptoms including sleep. For example, beta frequency (13–30 Hz) oscillations are associated with worsened bradykinesia while awake and decrease during non-rapid eye movement sleep. LFP investigation of sleep has largely focused on the subthalamic nucleus (STN), though corresponding oscillatory activity has been found in the globus pallidus internus (GPi) and thalamus as well. LFPs are increasingly being recognized as a potential biomarker for sleep states in PD, which may allow for closed-loop optimization of DBS parameters to treat sleep disturbances in this population. In this review, we discuss the relationship between LFP oscillations in STN and the sleep architecture of PD patients, current trends in utilizing DBS to treat sleep disturbance, and future directions for research. In particular, we highlight the capability of novel technologies to capture and record LFP data in vivo, while patients continue therapeutic stimulation for motor symptoms. These technological advances may soon allow for real-time adaptive stimulation to treat sleep disturbances.

The Neurophysiology of Sleep in Parkinson's Disease

Sleep disturbances are among the most common nonmotor complications of Parkinson's disease (PD), can present in prodromal stages, and progress with advancing disease. In addition to being a symptom of neurodegeneration, sleep disturbances may also contribute to disease progression. Currently, limited options exist to modulate sleep disturbances in PD. Studying the neurophysiological changes that affect sleep in PD at the cortical and subcortical level may yield new insights into mechanisms for reversal of sleep disruption. In this article, we review cortical and subcortical recording studies of sleep in PD with a particular focus on dissecting reported electrophysiological changes. These studies show that slow-wave sleep and rapid eye movement sleep are both notably disrupted in PD. We further explore the impact of these electrophysiological changes and discuss the potential for targeting sleep via stimulation therapy to modify PD-related motor and nonmotor symptoms. © 2021 International Parkinson and Movement Disorder Society.

Les temps de la dépression

Revue à travers les données de la littérature, la dépression apparaît comme un sujet de recherche très important, qui a déjà suscité de nombreuses théories chronobiologiques, souvent fondées sur des ≪critères diagnostiques objectifs≫. En revanche, l’impact thérapeutique de ces approches reste souvent limité à de rares services ultraspécialisés où les patients déprimés sont adressés en dernier recours.

Dans cet article, les auteurs passent en revue quelques-unes des principales données de la littérature, en particulier celles qui concernent les aspects chronobiologiques de la dépression. Les investigations sophistiquées réalisées dans les unités de recherche peuvent avoir certaines conséquences cliniques et pratiques qui sont également évoquées. En effet, une évaluation clinique soigneuse, orientée sur des bases chronobiologiques suffit bien souvent à proposer des traitements individuels assez simples. Parmi ceux-ci, la privation partielle de sommeil (PPS) représente un moyen utile, permettant une amélioration rapide, mais malheureusement souvent imprévisible et transitoire, des troubles de l’humeur. Il semble possible de rendre plus fiables les PPS grâce à des interventions sur la température, la prise de nourriture et l’exposition à la lumiére.

De plus, les auteurs décrivent un moyen possible de pérenniser les effets antidépresseurs de la PPS par des «microprivations de sommeil» réalisées pendant 15 min, à un moment spécifique de la nuit. Les résultats concernant 11 patients déprimés graves soumis à cette méthode sont exposés, 7 de ces sujets étant maintenus depuis 6 à 20 mois dans un état euthymique.

The relationship between sleep and cognition in Parkinson's disease: A meta-analysis

It is well established that sleep disorders have neuropsychological consequences in otherwise healthy people. Studies of night-time sleep problems and cognition in Parkinson's disease (PD), however, paint a mixed picture, with many reporting no relationship between sleep problems and neuropsychological performance. This review aimed to meta-analyse this research and to examine the factors underlying these mixed results. A literature search was conducted of published and unpublished studies, resulting in 16 papers that met inclusion criteria. Data were analysed in the domains of: global cognitive function; memory (general, long-term verbal recognition, long-term verbal recall); and executive function (general, shifting, updating, inhibition, generativity, fluid reasoning). There was a significant effect of sleep on global cognitive function, long-term verbal recall, long-term verbal recognition, shifting, updating, generativity, and fluid reasoning. Although there are effects on memory and executive function associated with poor sleep in PD, the effects were driven by a small number of studies. Numerous methodological issues were identified. Further studies are needed reliably to determine whether disturbed sleep impacts on cognition via mechanisms of hypoxia, hypercapnia, sleep fragmentation, chronic sleep debt or decreased REM and/or slow wave sleep in PD, as this may have important clinical implications.

NREM sleep alpha and sigma activity in Parkinson's disease: evidence for conflicting electrophysiological activity?

OBJECTIVES

Sleep EEG spectral patterns were investigated in eight newly diagnosed, non-depressed, non-demented, drug-naïve Parkinson's disease patients compared to nine controls.

METHODS

Mean relative spectral power density calculated for 0.25 Hz frequency bins and for classical EEG frequency bands.

RESULTS

Differences between patients and controls were most prominent in non-REM sleep, specially around 8.6 Hz (slow alpha), 12.5 Hz (fast alpha/slow sigma) and 15 Hz (fast sigma). Slow alpha showed lower p-values over frontal and occipital electrodes, whereas fast sigma activity was more important on central and parietal sites. Significantly increased NREM sleep alpha activity was found in left and right frontal (Mann-Whitney U=12,000, p=.021; U=14,000, p=.036), left and right central (U=14,000, p=.036), left parietal and left occipital (U=13,000, p=.027; U=15,000, p=.046) areas. Increased sigma activity was found in right frontal (U=14,000, p=.036), left central (U=12,000, p=.021), left and right parietal (U=12,000, p=.021; U=13,000, p=.027) and left occipital (U=15,000, p=.046) areas.

CONCLUSIONS

Concomitantly increased scalp EEG alpha and sigma activity was found during NREM sleep in initial Parkinson's disease.

SIGNIFICANCE

These non-REM sleep microstructure changes may represent evidence for altered electrophysiological mechanisms leading to sleep-wake instability in early disease stages.

Rating scales and questionnaires for assessment of sleep disorders in Parkinson's disease: what they inform about?

Sleep disorders are very prevalent in Parkinson's disease (PD) and include a diversity of disturbances. Rating scales and questionnaires are widely used to assess the presence and severity of the sleep disorders. The objective is to review rating scales and questionnaires used for assessment of sleep disorders in PD. To this purpose, a description and update of the sleep scales reviewed by the ad hoc Movement Disorder Society task force (MDS-TF) and other sleep disorder assessments was performed. Two specific (Parkinson's Disease Sleep Scale and Scales for Outcomes in PD Sleep) and two generic scales (Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale) were "Recommended" by the MDS-TF as they were used in PD patients, by researchers others than their developers and properly validated. Two other generic scales (Inappropriate Sleep Composite Score and Stanford Sleepiness Scale), "Suggested" due to incomplete validation, are also reviewed. Other instruments included in this review are three comprehensive PD-specific instruments for assessing multiple domains in addition to sleep problems (e.g., Non-Motor Symptoms Questionnaire, Non-Motor Symptoms Scale, MDS-UPDRS), and three generic instruments focused on particular disturbances (e.g., International Restless Legs Syndrome Study Group Rating Scale, REM behavioral disorders questionnaires), although these latter lack formal validation in PD populations. The "Recommended" instruments cover satisfactorily the needs for screening and evaluation of the nocturnal sleep disorders and daytime sleepiness in PD patients. It would be convenient to validate or complete the validation in PD populations of those instruments that cannot be recommended due to the lack of information on their clinimetric attributes.

Continuous positive airway pressure improves sleep and daytime sleepiness in patients with Parkinson disease and sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), common in Parkinson disease (PD), contributes to sleep disturbances and daytime sleepiness. We assessed the effect of continuous positive airway pressure (CPAP) on OSA, sleep, and daytime sleepiness in patients with PD.

DESIGN

This was a randomized placebo-controlled, crossover design. Patients with PD and OSA were randomized into 6 w of therapeutic treatment or 3 w of placebo followed by 3 w of therapeutic treatment. Patients were evaluated by polysomnography (PSG) and multiple sleep latency test (MSLT) pretreatment (baseline), after 3 w, and after 6 w of CPAP treatment. Analyses included mixed models, paired analysis, and within-group analyses comparing 3 w to 6 w of treatment.

SETTING

Sleep laboratory.

PARTICIPANTS

Thirty-eight patients with PD (mean age = 67.2 ± 9.2 y; 12 females).

INTERVENTION

Continuous positive airway pressure.

MEASUREMENTS

PSG OUTCOME MEASURES: sleep efficiency, %sleep stages (N1, N2, N3, R), arousal index, apnea-hypopnea index (AHI), and % time oxygen saturation < 90% (%time SaO2 < 90%). MSLT outcome measures: mean sleep-onset latency (MSL).

RESULTS

There were significant group-by-time interactions for AHI (P < 0.001), % time SaO2 < 90% (P = 0.02), %N2 (P = 0.015) and %N3 (P = 0.014). Subjects receiving therapeutic CPAP showed significant decrease in AHI, %time SaO2 < 90%, %N2, and significant increase in %N3 indicating effectiveness of CPAP in the treatment of OSA, improvement in nighttime oxygenation, and in deepening sleep. The paired sample analyses revealed that 3 w of therapeutic treatment resulted in significant decreases in arousal index (t = 3.4, P = 0.002). All improvements after 3 w were maintained at 6 w. Finally, 3 w of therapeutic CPAP also resulted in overall decreases in daytime sleepiness (P = 0.011).

CONCLUSIONS

Therapeutic continuous positive airway pressure versus placebo was effective in reducing apnea events, improving oxygen saturation, and deepening sleep in patients with Parkinson disease and obstructive sleep apnea. Additionally, arousal index was reduced and effects were maintained at 6 weeks. Finally, 3 weeks of continuous positive airway pressure treatment resulted in reduced daytime sleepiness measured by multiple sleep latency test. These results emphasize the importance of identifying and treating obstructive sleep apnea in patients with Parkinson disease.

Disease and Degeneration of Aging Neural Systems that Integrate Sleep Drive and Circadian Oscillations

Sleep/wake and circadian rest-activity rhythms become irregular with age. Typical outcomes include fragmented sleep during the night, advanced sleep phase syndrome and increased daytime sleepiness. These changes lead to a reduction in the quality of life due to cognitive impairments and emotional stress. More importantly, severely disrupted sleep and circadian rhythms have been associated with an increase in disease susceptibility. Additionally, many of the same brain areas affected by neurodegenerative diseases include the sleep and wake promoting systems. Any advances in our knowledge of these sleep/wake and circadian networks are necessary to target neural areas or connections for therapy. This review will discuss research that uses molecular, behavioral, genetic and anatomical methods to further our understanding of the interaction of these systems.

Rapid-eye-movement sleep behaviour disorder and neurodegenerative diseases

Rapid-eye-movement (REM) sleep behaviour disorder (RBD) is characterised by loss of muscular atonia and prominent motor behaviours during REM sleep. RBD can cause sleep disruption and severe injuries for the patient or bed partner. The disorder is strongly associated with neurodegenerative diseases, such as multiple-system atrophy, Parkinson's disease, dementia with Lewy bodies, and progressive supranuclear palsy. In many cases, the symptoms of RBD precede other symptoms of these neurodegenerative disorders by several years. Furthermore, several recent studies have shown that RBD is associated with abnormalities of electroencephalographic activity, cerebral blood flow, and cognitive, perceptual, and autonomic functions. RBD might be a stage in the development of neurodegenerative disorders and increased awareness of this could lead to substantial advances in knowledge of mechanisms, diagnosis, and treatment of neurodegenerative disorders.

Sleep disturbances and excessive daytime sleepiness in Parkinson disease: an overview

Sleep disturbances are frequent in Parkinson disease. These disorders can be broadly categorized into those that involve nocturnal sleep and excessive daytime sleepiness. The disorders that are often observed during the night in PD include sleep fragmentation that may be due to recurrent PD symptoms, sleep apnea, Restless Leg Syndrome/ periodic limb movements and REM sleep behavior disorder. Excessive daytime sleepiness is also a common occurrence in PD. EDS can arise from several etiologies, and patients may have more than one etiology responsible. The causes of EDS include nocturnal sleep disorder with sleep deprivation and resulting daytime somnolence, the effect of drugs used to treat PD, and possibly neurodegeneration of central sleep/wake areas. Appropriate diagnosis of the sleep disturbance affecting a PD patient can lead to specific treatments that can consolidate nocturnal sleep and enhance daytime alertness.

Sleep physiology and pathology: pertinence to psychiatry

Sleep should not be considered a behavioural state characterized by brain inertia; instead, it is a highly dynamic process involving numerous brainstem areas and all physiological systems of the body. Our understanding of the underlying mechanisms responsible for sleep regulation has considerably advanced since the discovery of rapid eye movement (REM) sleep, about half a century ago. Based on standardized electroencephalographic, electro-oculographic and electromyographic features, two distinct main states periodically alternating throughout the night have been identified: REM and non-REM sleep; the latter is further distinguished into stages 1, 2, 3 and 4. Computerized analysis of sleep recordings yielded more detailed information on sleep physiology and pathology. Although still preliminary, neuroimaging studies promise to elucidate the functional alterations of neuronal substrates during sleep. Regarding sleep disorders, which account for a substantial individual and socio-economic burden, considerable progress has been achieved in terms of their classification, assessment, clinical diagnosis and treatment. Specific sleep disorders within the three major categories, that is, 'dysomnias', 'parasomnias', and 'sleep disorders associated with mental, neurologic, or other medical conditions', exhibit characteristic clinical features; sleep laboratory recordings considerably assist to definitely diagnose several among them. Pertinence of sleep medicine for psychiatrists is obvious, taking into consideration that psychiatric disorders account for the largest diagnostic group of patients with sleep problems. In fact, the basics of this interdisciplinary field should be of special concern both to medical students and clinicians of diverse backgrounds who are interested in acquiring the necessary skills to globally and comprehensively understand and eventually effectively treat their patients.

Sleep and sleepiness in patients with Parkinson's disease before and after dopaminergic treatment

Sleep disturbances and daytime sleepiness are well-known phenomena in Parkinson's disease (PD). Fifteen previously untreated PD patients underwent clinical evaluation, subjective sleep evaluation and polysomnographic evaluation (PSG) before and after a treatment period of mean 8+/-3.1 months with dopaminergic drugs. Both mean Unified Parkinson's Disease Rating Scale (UPDRS) total score and mean subset III of the UPDRS were significantly improved with dopaminergic treatment. PSG revealed that administration of dopaminergic drugs resulted in significant increase in mean percentage of stages 1 and 2. The mean Epworth Sleepiness Scale (ESS) score was significantly increased and mean Multiple Sleep Latency Test (MSLT) score was significantly decreased after dopaminergic treatment indicating subjective and objective daytime sleepiness. The differences in MSLT scores were best explained by a higher dose of L-dopa, whereas other variables such as disease duration, treatment duration, Hoehn and Yahr stage, sleep efficiency index or dopamine agonists did not increase the significance. In contrast, any of the variables appeared to explain ESS score variability. This study demonstrates that daytime sleepiness is not present in untreated patients but emerges later during dopaminergic treatment. Total daily L-dopa dose is predictive of objective daytime sleepiness. Furthermore, subjective assessment of sleepiness may cause underestimation of the severity of daytime sleepiness.

[18F]fluorodopa uptake in the upper brainstem measured with positron emission tomography correlates with decreased REM sleep duration in early Parkinson's disease

Sleep disturbances are common in patients with Parkinson's disease (PD). Previous studies have shown alterations of polysomnographic sleep parameters in PD, such as overall diminution of slow-wave and REM sleep duration, absence of muscle atonia during REM and increased occurrence of periodic leg movements during sleep. The pathogenesis of sleep dysregulation in PD is unknown. The aim of this study was to determine relations of abnormal polysomnographic sleep parameters and the dopaminergic function of the striatum and the upper brainstem measured with the use of positron emission and magnetic resonance tomography in 10 early-stage PD patients with a history of sleep disturbances. Our data demonstrated a significant inverse correlation of absolute and percentage REM sleep duration with the mesopontine [18F]6-fluorodopa (FDOPA) uptake in PD patients. Therefore, the results point to a REM inhibiting effect of increased monaminergic transmission within the upper brainstem in early-stage PD. This finding emphasises the pathophysiological significance of a disturbed neurotransmitter equilibrium in the rostral brainstem for REM sleep alterations in PD.

Parkinson's disease and sleep

Sleep disorders are common in Parkinson's disease (PD), as almost two thirds of PD patients report them. From a clinical point of view, they can be classified into disorders of initiation and maintenance of sleep (DIMS), parasomnias, and excessive daytime sleepiness (EDS). Among the causes of DIMS are degenerative changes in the CNS affecting centers for sleep regulation, persistence into the night of daytime PD-related symptoms, concomitant medical or psychiatric disease, disruption of circadian rhythms, and effects of dopaminergic (and other) medication on sleep regulation. Parasomnias might further contribute to sleep disturbance, as they can be accompanied by motor desinhibition during REM sleep. Parasomnias can precede by several years the presence of daytime PD symptoms. EDS has been over the last years the focus of attention for both sleep and movement disorders specialists, due to the fact that it might predispose to traffic accidents. However, the so-called "sleep attacks" never occur without preexisting somnolence. Thus, a careful sleep history can be helpful to determine which patients are exposed to suffer them. Although EDS was initially attributed to the effects of dopaminergic medication, it seems likely that several disease-related factors might also play an important role. An adequate education of the PD patients in sleep hygiene measures and a skilled use of the medication seem necessary to prevent sleep disturbance.

Physiological and anatomical link between Parkinson-like disease and REM sleep behavior disorder

Parkinson's disease (PD) is a progressive neurodegenerative disease that is caused by a loss of neurons in the ventral midbrain. Parkinsonian patients often experience insomnia, parasomnias, and daytime somnolence. REM sleep behavior disorder (RBD) is characterized by vigorous movements during REM sleep, and may also be caused by neuronal degeneration in the central nervous system (CNS); however, the site of degeneration remains unclear. Both Parkinsonism and RBD become more prevalent with aging, with onset usually occurring in the sixties. Recent findings show that many individuals with RBD eventually develop Parkinsonism. Conversely, it is also true that certain patients diagnosed with Parkinsonism subsequently develop RBD. Postmortem examination reveals that Lewy bodies, Lewy neurites, and alpha-synuclein are found in brainstem nuclei in both Parkinsonism and RBD patients. In this article, we will discuss evidence that Parkinsonism and RBD are physiologically and anatomically linked, based on our animal experiments and other studies on human patients.

Manganese neurotoxicity: behavioral, pathological, and biochemical effects following various routes of exposure

The human central nervous system is an important target for manganese intoxication, which causes neurological symptoms similar to those of Parkinson's disease. With the increasing use of methylcyclopentadienyl manganese tricarbonyl (MMT) as an octane-improving additive to unleaded gasoline, the prospect of worldwide manganese exposure is once again attracting attention as increases in environmental manganese concentrations have been recorded relative to traffic density. One crucial question is whether a small increase of manganese contamination resulting from the widespread use of MMT could have neurotoxic effects. In this review we concentrate on central nervous system abnormalities and neurobehavioral disturbances. Most experimental animal studies on manganese neurotoxicity have been conducted in nonhuman primates and rodents. Most studies performed in rodents used oral manganese administration and did not assess bioaccumulation or central nervous system changes. The major effect found was transient modification of spontaneous motor activity. Very few inhalation toxicological studies were carried out. As manganese intoxication in humans usually occurs via inhalation, more studies are required using the respiratory route of administration. Given the proven neurotoxic effects of manganese and the prospect of worldwide MMT usage, this metal should be considered a new environmental pollutant having potentially widespread public health consequences.

Sleep and brain lesions: a critical review of the literature and additional new cases

We present a comprehensive review of sleep studies performed in patients with brain lesions complemented by 16 additional personal selected cases and by discussion of the corresponding animal data. The reader is cautioned about the risk of establishing an erroneous correlation between abnormal sleep and a given disorder due to the important inter and intra variability of sleep parameters among individuals. Salient points are stressed: the high frequency of post-stroke sleep breathing disorders is becoming increasingly recognised and may, in the near future, change the way this condition is managed. Meso-diencephalic bilateral infarcts induce a variable degree of damage to both waking and non-REM sleep networks producing and abnormal waking and sometimes a stage 1 hypersomnia reduced by modafinil or bromocriptine, which can be considered as a syndrome of cathecholaminergic deficiency. Central pontine lesions induce REM and non-REM sleep insomnia with bilateral lateral gaze paralysis. Bulbar stroke leads to frequent sleep breathing disorders. Polysomnography can help define the extent of involvement of various degenerative diseases. Fragmented sleep in Parkinson's disease may be preceded by REM sleep behavioural disorders. Multiple system atrophies are characterised by important sleep disorganization. Sleep waking disorganization and a specific ocular REM pattern are often seen in supra-nuclear ophtalmoplegia. In Alzheimer patients, sleep perturbations parallel the mental deterioration and are possibly related to cholinergic deficiency. Fronto-temporal dementia may be associated with an important decrease in REM sleep. Few narcoleptic syndromes are reported to be associated with a tumour of the third ventricle or a multiple sclerosis or to follow a brain trauma; all these cases raise the question whether this is a simple coincidence, a revelation of a latent narcolepsy or, as in non-DR16/DQ5 patients, a genuine symptomatic narcolepsy. Trypanosomiasis and the abnormal prion protein precociously after sleep patterns. Polysomnography is a precious tool for evaluating brain function provided it is realised under optimal conditions in stable patients and interpreted with caution. Several unpublished cases are presented: one case of pseudohypersomnia due to a bilateral thalamic infarct and corrected by modafinil, four probable late-onset autosomal recessive cerebellar ataxias without sleep pattern anomalies, six cases of fronto-temporal dementia with strong reduction in total sleep time and REMS percentage on the first polysomnographic night, one case of periodic hypersomnia associated with a Rathke's cleft cyst and four cases of suspected symptomatic narcolepsy with a DR16-DQ5 haplotype, three of which were post-traumatic without MRI anomalies, and one associated with multiple sclerosis exhibiting pontine hyper signals on MRI.

Sleep disorders and depression in patients with Parkinson's disease

OBJECTIVES

Sleep disorders and depression are frequent in patients with Parkinson's disease (PD). However, the exact prevalence and the causality are still unknown.

PATIENTS AND METHODS

We interviewed 56 consecutive PD patients and 59 age-matched healthy controls concerning sleep disorders and depression. Sleep Disorders Questionnaire (SDQ) and Zung Depression Scale (ZDS) were used as standardized valid and reliable psychometric tests.

RESULTS

Patients with PD had significantly higher values in the clinical-diagnostic scale narcolepsy (P=0.01), correlating with the L-dopa dose (P=0.007). Concerning sleep apnea (P=0.49), psychiatric sleep disorder (P=1.00) and periodic limb movement disorder (P=0.12), no significant difference could be identified. PD patients showed significantly higher depression scores than healthy control subjects (P=0.01), increasing with the duration of PD (P=0.04).

CONCLUSION

The significant higher narcolepsy score in PD patients must be seen due to dopaminergic medication and PD-specific neurodegeneration and immobility rather than due to narcolepsy. This leads to the conclusion that extreme caution is advised when carrying out the SDQ and interpreting the results in various persons and patient groups with motor problems. The strong association of depression, disease severity and sleep disorders in PD patients underlines the importance of identifying and treating both conditions in these patients.

Increased alpha activity in REM sleep in de novo patients with Parkinson's disease

We compared the sleep structure including a quantitative electroencephalographic (EEG) analysis and the frequency of periodic limb movements (PLM) in 17 patients with Parkinson's disease (PD; 10 men, seven women, mean age 65.9 years, mean Hoehn and Yahr stage 1.8) who had never been treated with dopaminergic agents (de novo), and 10 healthy controls (six men, four women, mean age 64.5 years). The REM sleep EEG of the PD patients was characterized by a sustained increase in the high-theta/alpha (7.8-10.5 Hz) frequency range during the first one-third (i.e., 11.00 p.m. to 01.40 a.m.) of the night. There was no significant difference in the sleep continuity and sleep architecture as well as in the PLM index between both groups. The analysis of the temporal dynamics of the observed changes suggests a dysregulation of the REM sleep homeostasis in the patients with PD.

Sleep spindle characteristics in healthy subjects of different age groups

OBJECTIVES

Few studies have quantified the various characteristics of sleep spindles (SS) in groups of normal human subjects. The aim of the present study was to look at the effects of age on the number, density, duration, intra-spindle frequency, and periodicity of SS during stage 2 sleep in normal subjects of different age groups.

METHODS

Thirty-six healthy subjects participated in the study. They were divided into 6 age groups: 10-19, 20-29, 30-39, 40-49, 50-59 and 60-69 years.

RESULTS

The results show that there is a progressive decrease in SS number, density, duration and a progressive increase in intra-spindle frequency with age. These changes occur mainly in the first 4 decades, except for SS number and density, for which the changes seem to continue until the sixth decade. The present study also reveals a clear periodicity of SS in human sleep. SS occur every 3-6 s, and the modal value of inter-spindle intervals increases with aging.

CONCLUSIONS

The progressive decrease in the number of SS and slow-wave sleep time with age suggests that SS are part of sleep promoting mechanisms. The negative correlation found between SS density and sleep efficiency in the present study is congruent with the sleep maintenance role of SS.

Treatment with weak electromagnetic fields restores dream recall in a parkinsonian patient

Absent or markedly reduced REM sleep with cessation of dream recall has been documented in numerous neurological disorders associated with subcortical dementia including Parkinson's disease, progressive supranuclear palsy and Huntington's chorea. This report concerns a 69 year old Parkinsonian patient who experienced complete cessation of dreaming since the onset of motor disability 13 years ago. Long term treatment with levodopa and dopamine (DA) receptor agonists (bromocriptine and pergolide mesylate) did not affect dream recall. However, dreaming was restored after the patient received three treatment sessions with AC pulsed picotesla range electromagnetic fields (EMFs) applied extracranially over three successive days. Six months later, during which time the patient received 3 additional treatment sessions with EMFs, he reported dreaming vividly with intense colored visual imagery almost every night with some of the dreams having sexual content. In addition, he began to experience hypnagogic imagery prior to the onset of sleep. Cessation of dream recall has been associated with right hemispheric dysfunction and its restoration by treatment with EMFs points to right hemispheric activation, which is supported by improvement in this patient's visual memory known to be subserved by the right temporal lobe. Moreover, since DA neurons activate REM sleep mechanisms and facilitate dream recall, it appears that application of EMFs enhanced DA activity in the mesolimbic system which has been implicated in dream recall. Also, since administration of pineal melatonin has been reported to induce vivid dreams with intense colored visual imagery in normal subjects and narcoleptic patients, it is suggested that enhanced nocturnal melatonin secretion was associated with restoration of dream recall in this patient. These findings demonstrate that unlike chronic levodopa therapy, intermittent pulsed applications of AC picotesla EMFs may induce in Parkinsonism reactivation of reticular-limbic-pineal systems involved in the generation of dreaming.

Drug-induced sleep disturbances. Focus on nonpsychotropic medications

Different medications can have significant effects on sleep quality and/or quantity. When prescribing medications it is important to be aware of these possible adverse effects of drugs. Disturbances of the sleep/wake cycle caused by medications can vary and include insomnia, daytime sleepiness, nightmares and changes in the sleep architecture. Psychotropic drugs are well known to have an effect on the sleep/wake cycle, but there is only limited information about the sleep effects of nonpsychotropic medications. Cardiovascular drugs, especially beta-blockers, which are widely used drugs, often change the sleep architecture and cause nightmares and insomnia. Both of these effects can be a potential source of noncompliance. Because of the complicated relationship between sleep, nocturnal asthma and antiasthmatic agents, the appropriate dosage and timing of medications should always be considered. Patients with Parkinson's disease often experience disrupted sleep due to their disorder and the adverse effects of anti-parkinsonian medications.

Sleep and degenerative neurologic disorders

This article summarizes sleep disturbances in a variety of neuro-degenerative diseases, including Parkinson's disease, multiple system atrophy, and amyotrophic lateral sclerosis. Sleep complaints in these conditions include insomnia, hypersomnia, abnormal motor activity and behavior during sleep, sleep-related breathing problems, and circadian rhythm sleep disturbances. Clinical examination followed in selected cases by polysomnographic, multiple sleep latency, and other laboratory tests is essential for correct diagnosis and treatment of these sleep disturbances.

Disruptive nocturnal behavior in Parkinson's disease and Alzheimer's disease

Disruptive nocturnal behavior, often referred to as sundowning, is a commonly encountered clinical problem in most forms of dementia. This study compared disruptive nocturnal behavior in patients with Alzheimer's disease (AD) and Parkinson's disease (PD). Questionnaire data were collected from 60 AD and 48 PD caregivers. Respondents were asked to record the typical time of day when any of seven disruptive behaviors were evidenced in their patients, if at all. Two scores were computed: (1) a sundowning score (number of nocturnal disruptive behaviors, range 0-7), and (2) a total score (number of disruptive behaviors without regard to time, range 0-7). Results indicated PD patients were more likely than AD patients to exhibit disruptive nocturnal behavior. The dose, timing, or number of years on antiparkinsonian medication were not related to nocturnal disruptive behavior within the PD patient group. These findings raise the possibility that sundowning in PD patients may be a manifestation of dopaminergic depletion within the basal ganglia or other abnormalities involving the cholinergic, serotoninergic and/or noradrenergic systems in the brainstem.

[The influence of sleep on abnormal waking movements]

Sleep decreases considerably the abnormal movements seen during waking in the degenerative extra-pyramidal diseases. However, the electrophysiologic recordings reveal that muscular contractions are not completely abolished. This decrease parallels the reduction of the waking system which act likely as a non-specific system of amplification. One can notice that sleep modifies the characteristics of the parkinsonian tremor and that some palatal myoclonias persist during sleep.

Polysomnographic sleep measures in Parkinson's disease patients with treatment-induced hallucinations

Prior studies of sleep in Parkinson's disease (PD) have been compromised by inadequate comparison groups, mixed medication regimens, and absence of quantitative data collection. This is the first study to compare polysomnographic sleep measures in PD patients on only dopaminergic medications with and without hallucinations. We performed two consecutive nights of polysomnography in 10 nondepressed, nondemented PD patients, 5 with and 5 without hallucinations. All patients were being treated with carbidopa/levodopa and a dopaminergic agonist only. Hallucinators and nonhallucinators were group-matched for age, PD duration, severity, and medication doses. Both groups had abnormal sleep records. In particular, there was a reduction in K-complexes and spindle formation, and the frequent occurrence of motor activation during rapid eye movement (REM) sleep consistent with REM behavior disorder. The hallucinator group had a significantly lower sleep efficiency (0.25 in hallucinators vs 0.61 in nonhallucinators, p = 0.006), a reduced total REM sleep time (mean total REM sleep time, 3 minutes in hallucinators vs 50 in nonhallucinators; p = 0.005), and a reduced REM percentage (mean, 5% in hallucinators vs 20% in nonhallucinators; p = 0.011). This study demonstrates that advanced PD patients treated with dopaminergic agents have abnormal sleep patterns and that those with dopaminergic-induced hallucinations have significantly greater REM aberrations than nonhallucinating PD patients.

Cortical reactivity in REM sleep with tonic mentalis EMG activity induced by clomipramine: an evaluation by slow vertex response

Slow vertex response (SVR) to sound stimuli was used as an index to assess whether cortical reactivity in REM sleep with tonic mentalis EMG activity (stage 1-REM) corresponds to that in REM sleep or rather to that in stage 1 of NREM sleep. In 11 young adult subjects 3 night polygraphic records were made after administration of 25 or 50 mg of clomipramine or non-active placebo. Stage 1-REM was observed in the drug night in 8 of the 11 subjects. N1-P2 and P2-N2 amplitudes of SVR were markedly smaller in stage 1-REM than in stage 1, but were virtually of the same height in stage 1-REM and in stage REM. This indicates that cortical reactivity in stage 1-REM closely resembles the counterpart in stage REM. This finding corresponds well with the frequent emergence of vivid dreams in stage 1-REM, indicating that stage 1-REM observed in the present subjects probably represents REM sleep without muscle atonia.

Insomnia in neurological diseases

Sleep disturbance, common in many neurological diseases, can be caused by underlying CNS pathology, altered motor system function, associated cognitive and psychiatric disorders, secondary effects of the disease such as pain and immobility, and medication effects. Nocturnal behavioral disturbances are a major contributor to institutionalization of such patients, and respiratory abnormalities of sleep can be life-threatening. Rational approach to diagnosis and treatment can lead to significant improvements in many such patients.

Motor dyscontrol in narcolepsy: rapid-eye-movement (REM) sleep without atonia and REM sleep behavior disorder

Narcolepsy involves abnormalities of rapid-eye-movement (REM) sleep, including a short latency to the onset of REM sleep, hypnagogic hallucinations, and sleep paralysis. In addition, persistence of muscle tone by electromyographic criteria or excessive muscle twitching during REM sleep or both have been reported in treated and untreated narcoleptic patients. We report that another previously described abnormality of REM sleep, REM sleep behavior disorder, may also be a symptom of narcolepsy. This disorder was found in 10 narcoleptic patients during routine clinical evaluations involving polysomnography and multiple sleep latency tests. During REM sleep, 7 additional narcoleptic patients displayed persistent muscle tone and/or excessive twitching, which we believe to be subclinical components of REM sleep behavior disorder. These 17 patients, diagnosed by established criteria for narcolepsy and for REM sleep behavior disorder, ranged in age from 8 to 74 years. Seventy-one percent were male. Narcolepsy and REM sleep behavior disorder most commonly emerged in tandem. In 3 patients, treatment of narcolepsy-cataplexy with stimulants and tricyclics either induced or exacerbated REM sleep behavior disorder.

Sleep electroencephalogram at the early stage of Creutzfeldt-Jakob disease

We describe sleep EEG studies in three patients at the early stage of Creutzfeldt-Jakob disease. Little work has been devoted to the study of the sleep EEG in the course of the CJ disease: disorganized sleep architecture was noted, associated with a decrease in stage 4 and an almost complete disappearance of the REM stage. Our patients were considered to have normal stage 2; yet spindles and K complexes were rare at this stage. No evolution towards stage 4 was noted. The percentage of rapid eye movement sleep was significantly low in two cases and normal in one case. Sleep disturbances in the other dementing disorders are reported.

Sleep and cranial dystonia

A nocturnal polygraphic study was performed on 10 patients with cranial dystonia (blepharospasm (BS) and oromandibular dystonia (OMD)). All patients showed impaired sleep efficiency and reduced slow and REM sleep, more marked in subjects with severe dystonia. Abnormal muscular activity decreased progressively with deeper sleep and during the first hours of the night, without disappearing. A disordered hypnic++ pattern and impaired motor control even during sleep are typical features in cranial dystonia.

Nocturnal sleep in Huntington's disease

Nocturnal sleep was studied in 16 inpatients with Huntington's disease. In comparison with healthy controls, patients exhibited a disturbed sleep pattern with increased sleep onset latency, reduced sleep efficiency, frequent nocturnal awakenings, more time spent awake and less slow wave sleep. These abnormalities correlated in part with duration of illness, severity of clinical symptoms, and degree of atrophy of the caudate nucleus. Patients showed an increased density of sleep spindles.

REM sleep without muscle atonia (stage 1-REM) and its relation to delirious behavior during sleep in patients with degenerative diseases involving the brain stem

Nocturnal sleep was examined in 12 patients with degenerative diseases involving the brain stem and in 2 patients with late cerebellar cortical atrophy (LCCA). A peculiar sleep state, characterized by the concomitant appearance of a low-voltage mixed frequency EEG, rapid eye movements (REMs) and tonic EMG in mental muscles, repeatedly appeared during nocturnal sleep in all of the 12 patients with degenerative diseases involving the brain stem and it was called stage 1-REM after Tachibana et al. In 8 of the 12 patients, delirious or oneiric behavior appeared during, or soon after, the episodes of stage 1-REM. Inner experiences reported by one of the subjects well corresponded to his behavior during the episode of stage 1-REM. Stage 1-REM was not observed during nocturnal sleep of the patients with LCCA. These results indicate that a degenerative lesion in the brain stem induced stage 1-REM and delirious behavior during nocturnal sleep through abolishing muscle atonia of REM sleep and causing dissociation of the functional components characterizing REM sleep.

The significance of eye blink rate in parkinsonism: a hypothesis

Alterations in blink rate have been reported in several neuropsychiatric disorders presumed to result from abnormal central dopaminergic functions. Increased blink rate in schizophrenia, Tardive dyskinesia, Tourette's syndrome and Meige's disease are associated with enhanced dopaminergic functions. Parkinson's disease is associated with reduced dopaminergic functions and decreased blink rate. Thus, blink rate may reflect striatal and mesolimbic dopaminergic activity. Since acute light exposure suppresses melatonin production and darkness stimulates melatonin secretion, blinking may serve to regulate light-dark exposure to the pineal gland and thus to 'fine tune' melatonin production. As there is evidence to suggest that melatonin inhibits the release of dopamine in the striatum and limbic system, increased blink rate may serve to reduce light exposure, increase melatonin secretion and attenuate dopaminergic functions. Conversely, decreased blinking (as is observed in patients with Parkinson's disease) could reflect a compensatory mechanism to increase light exposure, reduce melatonin production and ultimately increase dopamine functions. This model is novel in that for the first time it suggests a functional link among blink rate, melatonin secretion and striatal dopaminergic functions in movement disorders.

Sleep disorders and sleep effect in Parkinson's disease

It has been suggested that sleep may have a positive effect on morning motor symptoms in Parkinson's disease (PD). We examined this possibility and also looked at common sleep disorders in PD. Seventy-eight PD patients and 43 normal elderly subjects answered a questionnaire. Of the PD patients, 43.6% reported improved motor symptoms in the morning, 37.2% worse, and 19.2% unchanged compared to the rest of the day. No difference was found between morning-better and -worse groups with respect to age, duration or stage of PD; antiparkinsonian medications utilized, and predominant motor symptoms. However, the morning-same group had a shorter duration of PD and less severe disease and required fewer dopaminergic medications. Sleep disorders were seen with equal frequency in the morning-better and -worse groups. Our results suggest that sleep does not have a direct effect on morning motor function. Alterations in morning motor symptomatology probably represent a manifestation of motor fluctuations. Sleep fragmentation and spontaneous daytime dozing occurred much more frequently in PD patients than controls. In addition, nocturnal vocalizations and daytime hallucinations occurred only in the PD group.