Sleep and quantitative EEG in patients with progressive supranuclear palsy

AAV8-P301L tau expression confers age-related disruptions in sleep quantity and timing

Sleep timing and quantity disturbances persist in tauopathy patients. This has been studied in transgenic models of primary tau neuropathology using traditional electroencephalograms (EEGs) and more recently, the PiezoSleep Mouse Behavioral Tracking System. Here, we generated a primary tauopathy model using an intracerebroventricular injection of human mutant hSyn-P301L-tau, using adeno-associated virus of serotype 8 (AAV8). We discovered distinctions in sleep architecture with altered quantity and timing in AAV8-P301L tau expressing mice of both sexes using the noninvasive PiezoSleep System. The AAV8-P301L tau mice exhibit striking age-related increases in sleep duration specifically at the active phase onset, suggesting a critical and sensitive time-of-day for tauopathy related sleep disturbances to occur. Since our findings show sleep behavior changes at specific transitional periods of the day, tau neuropathology may impact normal diurnal variation in biological processes, which should be explored using the AAV8-P301L tauopathy model.

Louis EK. Proof-of-concept for characterization of neurodegenerative disorders utilizing two non-REM sleep biomarkers

Study objective

This proof-of-concept study aimed to determine whether the combined features of two non-rapid eye movement (NREM) sleep biomarkers acquired predominantly in-home could characterize different neurodegenerative disorders.

Methods

Sleep spindle duration and non-REM hypertonia (NRH) were evaluated in seven groups including a control group (CG = 61), and participants with isolated REM sleep behavior disorder (iRBD = 19), mild cognitive impairment (MCI = 41), Parkinson disease (PD = 16), Alzheimer disease dementia (ADem = 29), dementia with Lewy Bodies or Parkinson disease dementia (LBD = 19) and progressive supranuclear palsy (PSP = 13). One-way analysis of variance (ANOVA), Mann-Whitney U, intra-class (ICC) and Spearman ranked correlations, Bland-Altman plots and Kappa scores, Chi-square and Fisher exact probability test, and multiple-logistic regression were focused primarily on spindle duration and NRH and the frequencies assigned to the four normal/abnormal spindle duration/NRH combinations.

Results

ANOVA identified group differences in age, sleep efficiency, REM, NRH (p < 0.0001) and sleep time (p = 0.015), Spindle duration and NRH each demonstrated good night-to-night reliabilities (ICC = 0.95 and 0.75, Kappa = 0.93 and 0.66, respectively) and together exhibited an association in the PD and LBD groups only (p < 0.01). Abnormal spindle duration was greater in records of PSP (85%) and LBD (84%) patients compared to CG, MCI, PD and ADem (p < 0.025). Abnormal NRH was greater in PSP = 92%, LBD = 79%, and iRBD = 74% compared to MCI = 32%, ADem = 17%, and CG = 16% (p < 0.005).The combination biomarker normal spindle duration/normal NRH was observed most frequently in CG (56%) and MCI (41%). ADem most frequently demonstrated normal spindle duration/normal NRH (45%) and abnormal spindle duration/normal NRH (38%). Normal spindle duration/abnormal NRH was greatest in iRBD = 47%, while abnormal spindle duration/abnormal NRH was predominant in PSP = 85% and LBD = 74%.

Conclusion

The NREM sleep biomarkers spindle duration and NRH may be useful in distinguishing patients with different neurodegenerative disorders. Larger prospective cohort studies are needed to determine whether spindle duration and NRH can be combined for prodromal assessment and/or monitoring disease progression.

QEEG Signatures are Associated with Nonmotor Dysfunctions in Parkinson's Disease and Atypical Parkinsonism: An Integrative Analysis

Parkinson's disease (PD) and atypical parkinsonism (AP), including progressive supranuclear palsy (PSP) and multiple system atrophy (MSA), share similar nonmotor symptoms. Quantitative electroencephalography (QEEG) can be used to examine the nonmotor symptoms. This study aimed to characterize the patterns of QEEG and functional connectivity (FC) that differentiate PD from PSP or MSA, and explore the correlation between the differential QEEG indices and nonmotor dysfunctions in PD and AP. We enrolled 52 patients with PD, 31 with MSA, 22 with PSP, and 50 age-matched health controls to compare QEEG indices among specific brain regions. One-way analysis of variance was applied to assess QEEG indices between groups; Spearman's correlations were used to examine the relationship between QEEG indices and nonmotor symptoms scale (NMSS) and mini-mental state examination (MMSE). FCs using weighted phase lag index were compared between patients with PD and those with MSA/PSP. Patients with PSP revealed higher scores on the NMSS and lower MMSE scores than those with PD and MSA, with similar disease duration. The delta and theta powers revealed a significant increase in PSP, followed by PD and MSA. Patients with PD presented a significantly lower slow-to-fast ratio than those with PSP in the frontal region, while patients with PD presented significantly higher EEG-slowing indices than patients with MSA. The frontal slow-to-fast ratio showed a negative correlation with MMSE scores in patients with PD and PSP, and a positive correlation with NMSS in the perception and mood domain in patients with PSP but not in those with PD. Compared to PD, MSA presented enhanced FC in theta and delta bands in the posterior region, while PSP revealed decreased FC in the delta band within the frontal-temporal cortex. These findings suggest that QEEG might be a useful tool for evaluating the nonmotor dysfunctions in PD and AP. Our QEEG results suggested that with similar disease duration, the cortical neurodegenerative process was likely exacerbated in patients with PSP, followed by those with PD, and lastly in patients with MSA.

Sleep disturbances in the speech-language variant of progressive supranuclear palsy

INTRODUCTION

Progressive supranuclear palsy (PSP) variants other than PSP-Richardson Syndrome (PSP-RS) have been recognized, including PSP with speech and language problems (PSP-SL). Given the reported sleep disruptions in PSP-RS, we investigated sleep abnormalities in PSP-SL.

METHODS

Four sleep-related screening questions were given to the caregivers of 90 patients with PSP-SL (59 suggestive of PSP-SL and 31 possible PSP-SL) and 71 probable PSP-RS (prob. PSP-RS) patients.

RESULTS

At least one sleep-related disturbance was observed in 35.6% of suggestive of PSP-SL, 38.7% of possible PSP-SL, and 67.6% of prob. PSP-RS, the most common being "unable to fall or stay asleep". Prob. PSP-RS showed higher frequency of "screaming or talking in sleep", "acting out dreams", and "unable to fall or stay asleep" compared to both PSP-SL groups, but did not differ from possible PSP-SL in "excessive daytime sleepiness".

CONCLUSION

Sleep abnormalities are common in PSP-SL, but less frequent than prob.PSP-RS.

The circadian system in Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy

Circadian organization of physiology and behavior is an important biologic process that allows organisms to anticipate and prepare for predictable changes in the environment. Circadian disruptions are associated with a wide range of health issues. In patients with neurodegenerative diseases, alterations of circadian rhythms are among the most common and debilitating symptoms. Although a growing awareness of these symptoms has occurred during the last decade, their underlying neuropathophysiologic circuitry remains poorly understood and, consequently, no effective therapeutic strategies are available to alleviate these health issues. Recent studies have examined the neuropathologic status of the different neural components of the circuitry governing the generation of circadian rhythms in neurodegenerative diseases. In this review, we will dissect the potential contribution of dysfunctions in the different nodes of this circuitry to circadian alterations in patients with parkinsonism-linked neurodegenerative diseases (namely, Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy). A deeper understanding of these mechanisms will provide not only a better understanding of disease neuropathophysiology but also holds promise for the development of more effective and mechanisms-based therapies.

Sleep oscillation-specific associations with Alzheimer's disease CSF biomarkers: novel roles for sleep spindles and tau

BACKGROUND

Based on associations between sleep spindles, cognition, and sleep-dependent memory processing, here we evaluated potential relationships between levels of CSF Aβ42, P-tau, and T-tau with sleep spindle density and other biophysical properties of sleep spindles in a sample of cognitively normal elderly individuals.

METHODS

One-night in-lab nocturnal polysomnography (NPSG) and morning to early afternoon CSF collection were performed to measure CSF Aβ42, P-tau and T-tau. Seven days of actigraphy were collected to assess habitual total sleep time.

RESULTS

Spindle density during NREM stage 2 (N2) sleep was negatively correlated with CSF Aβ42, P-tau and T-tau. From the three, CSF T-tau was the most significantly associated with spindle density, after adjusting for age, sex and ApoE4. Spindle duration, count and fast spindle density were also negatively correlated with T-tau levels. Sleep duration and other measures of sleep quality were not correlated with spindle characteristics and did not modify the associations between sleep spindle characteristics and the CSF biomarkers of AD.

CONCLUSIONS

Reduced spindles during N2 sleep may represent an early dysfunction related to tau, possibly reflecting axonal damage or altered neuronal tau secretion, rendering it a potentially novel biomarker for early neuronal dysfunction. Given their putative role in memory consolidation and neuroplasticity, sleep spindles may represent a mechanism by which tau impairs memory consolidation, as well as a possible target for therapeutic interventions in cognitive decline.

Rating Scales for Movement Disorders With Sleep Disturbances: A Narrative Review

Introduction: In recent years, a wide variety of rating scales and questionnaires for movement disorders have been developed and published, making reviews on their contents, and attributes convenient for the potential users. Sleep disorders are frequently present in movement disorders, and some movement disorders are accompanied by specific sleep difficulties. Aim: The aim of this study is to perform a narrative review of the most frequently used rating scales for movement disorders with sleep problems, with special attention to those recommended by the International Parkinson and Movement Disorders Society. Methods: Online databases (PubMed, SCOPUS, Web of Science, Google Scholar), related references from papers and websites and personal files were searched for information on comprehensive or global rating scales which assessed sleep disturbances in the following movement disorders: akathisia, chorea, dystonia, essential tremor, myoclonus, multiple system atrophy, Parkinson's disease, progressive supranuclear palsy, and tics and Tourette syndrome. For each rating scale, its objective and characteristics, as well as a summary of its psychometric properties and recommendations of use are described. Results: From 22 rating scales identified for the selected movement disorders, only 5 included specific questions on sleep problems. Movement Disorders Society-Unified Parkinson's Disease Rating scale (MDS-UPDRS), Non-Motor Symptoms Scale and Questionnaire (NMSS and NMSQuest), Scales for Outcomes in Parkinson's Disease (SCOPA)-Autonomic and Progressive Supranuclear Palsy Rating Scale (PSPRS) were the only rating scales that included items for assessing sleep disturbances. Conclusions: Despite sleep problems are frequent in movement disorders, very few of the rating scales addresses these specific symptoms. This may contribute to an infra diagnosis and mistreatment of the sleep problems in patients with movement disorders.

Sleepless Night and Day, the Plight of Progressive Supranuclear Palsy

Objectives

To elucidate the unique sleep and waking characteristics in progressive supranuclear palsy (PSP), a neurodegenerative disease associated with motor deficits and dementia that largely affects the brainstem and thalamic regions.

Methods

A total of 20 PSP and 16 healthy older adult controls participated in this study. The participants underwent an overnight polysomnography and multiple sleep latency test (MSLT) the following day. Prior to the MSLT last trial, they were asked to complete the Stanford Sleepiness Scale. Data were assessed for measures of latency to sleep onset, sleep duration, waking, and sleep staging during the night. Mean sleep latency, a measure of daytime sleepiness, sleep onset rapid eye movement (REM) periods, and microsleeps were studied with the MSLT. Spectral analysis of wake electroencephalogram (EEG) was performed for 30-second periods at the start of each MSLT trial.

Results

PSP took significantly longer time to fall asleep (p < .001), slept less during the night (p ≤ .001), and had more wake after sleep onset than controls (p ≤ .001). PSP had less N2 sleep (p < .05) and N3 sleep (p < .05), and REM sleep (p < .001) than controls. During the MSLT, PSP took significantly longer to fall asleep (p < .001), did not have microsleeps when they remained awake throughout the assessment periods, but were subjectively sleepier than controls (p < .05). Gamma power was increased during wake EEG in PSP (p < .01).

Conclusions

Sleep/waking regulation and REM sleep regulation are disrupted in PSP, leading to profound sleep deprivation without recuperation. Our findings suggest a diminished homeostatic sleep drive in PSP. This hyperaroused state is unique and is a severely disabling feature of PSP.

Assessment of Sleep Spindle Density among Genetically Positive Spinocerebellar Ataxias Types 1, 2, and 3 Patients

Objective

The effect of thalamic degeneration in patients with spinocerebellar ataxias (SCA) and sleep spindle (SS) abnormalities has not been studied so far, although there is a strong association between these disorders. This study was done to evaluate and compare the SS densities (SSDs) of genetically proven autosomal dominant SCA1, SCA2 and SCA3 patients with controls.

Methods

Prospectively and genetically confirmed cases of SCA and controls were recruited. Patients were assessed clinically, were evaluated with sleep questionnaires and an overnight polysomnography was performed. SSDs were analyzed using neuroloop gain plugin of Polyman version 1.15 software.

Results

Eighteen patients of SCA1 (n = 6), SCA2 (n = 5), SCA3 (n = 7) and 6 controls were recruited in our study. The mean age of SCA1 patients was 39.2 ± 5.4, of SCA2 patients was 30.8 ± 9.5 and of SCA3 patients was 35.4 ± 6.4 years. The mean duration of illness in SCA1 was 4.7 ± 1.7 years, in SCA2 it was 4.3 ± 4.4 years and in SCA3 it was 5 ± 2.3 years. The median SSD values (percentage loop gain) during stage 2 of non-rapid eye movement sleep were 16.9% in SCA1, 0% in SCA2, 1.2% in SCA3 and 59.5% in controls. There was a significant difference in SSD values in SCA2 (p = 0.04), SCA3 (p = 0.02) patients and controls.

Conclusion

SSDs were significantly decreased in patients with SCA, which is a novel finding. This is likely due to the "thalamic switch" disruption, observed as reduced SSDs in SCA2 and SCA3. Sleep spindle deficits could act as one of the biomarkers of ongoing neurodegeneration in the thalamic circuitry of SCA patients.

Challenges in sleep stage R scoring in patients with autosomal dominant spinocerebellar ataxias (SCA1, SCA2 and SCA3) and oculomotor abnormalities: a whole night polysomnographic evaluation

OBJECTIVES

Spinocerebellar ataxias are progressive neurodegenerative disorders characterized by progressive cerebellar features with additional neuro-axis involvement. Oculomotor abnormality is one of the most frequent manifestations. This study was done to assess the polysomnographic abnormalities in patients with Spinocerebellar ataxia (SCA1, SCA2 and SCA3) and also to evaluate whether oculomotor abnormalities interfere with sleep stage R scoring.

METHODS

The study was carried out using 36 genetically positive SCA patients. All patients underwent neurological examination with special focus on oculomotor function (optokinetic nystagmus-OKN and extraocular movement restriction-EOM). The sleep quality was measured with Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Disease severity was assessed with International Cooperative Ataxia Rating Scale (ICARS). All the patients underwent over-night video-polysomnography (VPSG).

RESULTS

Out of 36 patients studied, the data of 34 patients [SCA1 (n = 12), SCA2 (n = 13), SCA3 (n = 9)] were used for final analysis. Patients from SCA1, SCA2, and SCA3 category did not show significant differences in age and diseases severity (ICARS). All patients had vertical OKN impairment. Oculomotor impairment was higher in SCA2 patients. Sleep macro-architecture analysis showed absent stage R sleep, predominantly in SCA2 (69%) followed by SCA3 (44%) and SCA1 (8%). Patients showed a strong negative correlation of stage R sleep percentage with disease severity and oculomotor dysfunction.

CONCLUSION

Voluntary saccadic eye movement velocity and rapid eye movements (REMs) in sleep are strongly correlated. The more severe the saccadic velocity impairment, the less likely was it to generate REMs (rapid eye movements) during stage R. Accordingly 69% of SCA2 patients with severe occulomotor impairments showed absent stage R as per the AASM sleep scoring. We presume that the impaired REMs generation in sleep could be due to oculomotor abnormality and has resulted in spuriously low or absent stage R sleep percentage in SCA patients with conventional VPSG scoring rules. The present study recommends the modification of AASM scoring rules for stage R in patients with oculomotor abnormalities.

Brain rhythm attractor breakdown in Alzheimer's disease: Functional and pathologic implications

This perspective binds emerging evidence on the bidirectional relationship between Alzheimer's disease (AD) and sleep disorders through a model of brain rhythm attractor breakdown. This approach explains behavioral-cognitive changes in AD across the sleep-wake cycle and supports a causal association between early brainstem tau pathology and subsequent cortical amyloid β accumulation. Specifically, early tau dysregulation within brainstem-hypothalamic nuclei leads to breakdown of sleep-wake attractor networks, with patients displaying an attenuated range of behavioral and electrophysiological activity patterns, a "twilight zone" of constant activity between deep rest and full alertness. This constant cortical activity promotes activity-dependent amyloid β accumulation in brain areas that modulate their activity across sleep-wake states, especially the medial prefrontal cortex. In addition, the accompanying breakdown of hippocampal-medial prefrontal cortex interplay across sleep stages could explain deficient memory consolidation through dysregulation of synaptic plasticity. Clinical implications include the potential therapeutic benefit of attractor consolidation (e.g., slow-wave sleep enhancers) in delaying AD progression.

Altered sleep and EEG power in the P301S Tau transgenic mouse model

Objective

Sleep disturbances are prevalent in human tauopathies yet despite the importance of sleep, little is known about its relationship with tau pathology. Here, we investigate this interaction by analyzing sleep and tau pathology throughout tauopathy disease progression in P301S human tau transgenic mice.

Methods

P301S and wild‐type mice were analyzed by electroencephalography (EEG)/electromyography at 3, 6, 9, and 11 months of age for sleep/wake time, EEG power, and homeostatic response. Cortical volume and tau pathology was also assessed by anti‐phospho‐tau AT8 staining.

Results

P301S tau mice had significantly decreased rapid eye movement (REM) sleep at 9 months of age and decreased REM and non‐REM (NREM) sleep as well as increased wakefulness at 11 months. Sleep loss was characterized by fewer wake, REM, and NREM bouts, increased wake bout duration, and decreased sleep bout duration. Decreased REM and NREM sleep was associated with increased brainstem tau pathology in the sublaterodorsal area and parafacial zone, respectively. P301S mice also showed increased EEG power at 6 and 9 months of age and decreased power at 11 months. Decreased EEG power was associated with decreased cortical volume. Despite sleep disturbances, P301S mice maintained homeostatic response to sleep deprivation.

Interpretation

Our results indicate that tau pathology is associated with sleep disturbances that worsen with age and these changes may be related to tau pathology in brainstem sleep regulating regions as well as neurodegeneration. Tau‐induced sleep changes could affect disease progression and be a marker for therapeutic efficacy in this and other tauopathy models.

Sleep in Alzheimer's Disease - Beyond Amyloid

Sleep disorders are prevalent in Alzheimer's disease (AD) and a major cause of institutionalization. Like AD pathology, sleep abnormalities can appear years before cognitive decline and may be predictive of dementia. A bidirectional relationship between sleep and amyloid β (Aβ) has been well established with disturbed sleep and increased wakefulness leading to increased Aβ production and decreased Aβ clearance; whereas Aβ deposition is associated with increased wakefulness and sleep disturbances. Aβ fluctuates with the sleep-wake cycle and is higher during wakefulness and lower during sleep. This fluctuation is lost with Aβ deposition, likely due to its sequestration into amyloid plaques. As such, Aβ is believed to play a significant role in the development of sleep disturbances in the preclinical and clinical phases of AD. In addition to Aβ, the influence of tau AD pathology is likely important to the sleep disturbances observed in AD. Abnormal tau is the earliest observable AD-like pathology in the brain with abnormal tau phosphorylation in many sleep regulating regions such as the locus coeruleus, dorsal raphe, tuberomammillary nucleus, parabrachial nucleus, and basal forebrain prior to the appearance of amyloid or cortical tau pathology. Furthermore, human tau mouse models exhibit AD-like sleep disturbances and sleep changes are common in other tauopathies including frontotemporal dementia and progressive supranuclear palsy. Together these observations suggest that tau pathology can induce sleep disturbances and may play a large role in the sleep disruption seen in AD. To elucidate the relationship between sleep and AD it will be necessary to not only understand the role of amyloid but also tau and how these two pathologies, together with comorbid pathology such as alpha-synuclein, interact and affect sleep regulation in the brain.

Sleep Disorders in Neurologic Practice: A Case-based Approach

Sleep disorders are common in neurology practice, but are often undiagnosed and untreated. Specific patient cohorts, such as older adults, patients residing in nursing homes, and patients with underlying chronic neurologic and psychiatric disorders, are at particular risk. If these sleep problems are not properly evaluated and managed the patient may experience exacerbation of the underlying neurologic disorder. This article highlights some of the key sleep disorders relevant to practicing neurologists, emphasizing hypersomnolence, insomnia, and sleep-related movement disorders in the setting of neurologic disorders to enhance the tools available for evaluation, and discusses management strategies.

Rest-activity rhythm disruption in progressive supranuclear palsy

OBJECTIVE/BACKGROUND

The brainstem is among the first regions affected in progressive supranuclear palsy (PSP) and is part of the sleep/circadian regulation network. In two small studies, blood pressure and core body temperature circadian patterns were disrupted in PSP; however, it is unclear if circadian activity rhythms are also affected. Our objective was to perform circadian analyses of the rest-activity rhythms in PSP and determine the association with increasing disease severity.

PATIENTS/METHODS

Individuals with a clinical PSP diagnosis (n = 17; nine men) and healthy older adults (n = 17; nine men) were selected for this study. Participants wore actigraphy wristbands and completed sleep diaries for up to 14 consecutive days. Data were analyzed to assess circadian activity strength (amplitude, mesor, f-ratio), phase (acrophase), and circadian stability (intradaily variability, interdaily stability, relative amplitude). Analyses controlled for sleep fragmentation, cognition, and self-reported depression. The association between disease severity using the PSP rating scale and circadian activity rhythm disruption was assessed.

RESULTS

Individuals with PSP had significantly lower circadian activity mesor (p ≤ 0.001), amplitude (p ≤ 0.001), robustness (f-ratio, p <0.01), relative amplitude (p ≤ 0.001), and interdaily stability (p ≤ 0.01), with increased intradaily variability (p <0.05). CAR remained weaker in PSP after controlling for sleep fragmentation, and again when also controlling for cognitive impairment and depression. Weaker circadian activity (mesor, amplitude, f-ratio, and relative amplitude) was associated with increased disease severity.

CONCLUSIONS

Circadian activity rhythms are disrupted in individuals with PSP as compared to controls, and worsen with disease severity. This is the first study of its kind to describe circadian activity rhythms in PSP.

Characteristics of Nonmotor Symptoms in Progressive Supranuclear Palsy

Objectives. To explore the clinical correlates of nonmotor symptoms (NMS) in progressive supranuclear palsy (PSP) and their differences from healthy controls and patients with Parkinson's disease (PD). Methods. Twenty-seven PSP patients, 27 age- and gender-matched healthy controls (HC), and 27 age- and gender-matched PD patients were included for this case-control study. NMS were assessed using the Nonmotor Symptoms Scale (NMSS, including 9 domains). Results. All PSP patients reported NMS. The frequency and severity of "sleep/fatigue," "mood/apathy," "attention/memory," "gastrointestinal," "sexual dysfunction," and "miscellaneous" domains in PSP group were significantly higher than those in HC group (P < 0.05). The frequency of "mood/apathy," "attention/memory," and "sexual dysfunction" domains and the severity of "attention/memory" and "gastrointestinal" domains in PSP group were significantly higher than those in PD group (P < 0.05). The "attention/memory" domain in PSP had a significant but weak-to-moderate correlation with age (R = 0.387, P = 0.046) and onset age (R = 0.406, P = 0.036). Conclusions. NMS are common in PSP patients. Patients with PSP seem to be subjected to more frequent and severe specific NMS compared to healthy aging subjects and PD patients. Older PSP patients and late-onset patients are likely to be subjected to cognitive decline.

Sleep Disorders in Atypical Parkinsonism

Sleep disorders are commonly seen in atypical parkinsonism, with particular disorders occurring more frequently in specific parkinsonian disorders. Multiple systems atrophy (MSA) is a synucleinopathy often associated with nocturnal stridor which is a serious, but treatable condition highly specific to MSA. In addition, this disorder is strongly associated with rapid eye movement (REM) sleep behavior disorder (RBD), which is also seen in dementia with Lewy bodies (DLB). RBD is far less prevalent in progressive supranuclear palsy (PSP), which is a tauopathy. Insomnia and impaired sleep architecture are the most common sleep abnormalities seen in PSP. Corticobasilar degeneration (CBD) is also a tauopathy, but has far fewer sleep complaints associated with it than PSP. In this manuscript we review the spectrum of sleep dysfunction across the atypical parkinsonian disorders, emphasize the importance of evaluating for sleep disorders in patients with parkinsonian symptoms, and point to sleep characteristics that can provide diagnostic clues to the underlying parkinsonian disorder.

Therapeutic options for nocturnal problems in Parkinson's disease and atypical parkinsonian disorders

Sleep disturbances in Parkinson's disease and parkinsonism (such as atypical parkinsonian disorders like multiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies and corticobasal degeneration) are multifactorial and as such treatment needs to be tailored to the specific patient case and sleep dysfunction. One also has to consider drug-related effects on sleep architecture. This article provides an overview of the therapeutic options for nocturnal problems in Parkinson`s disease and atypical parkinsonian disorders.

[Esophageal achalasia, sleep disorders and chorea in a tauopathy without ophthalmoplegia, parkinsonian syndrome, nor dementia (progressive supranuclear palsy?): clinicopathological study]

CONTEXT

Progressive supranuclear palsy (PSP) is classically characterized by supranuclear ophthalmoplegia, paroxysmal imbalance with backward falling, axial dystonia, rigidity, pseudobulbar palsy and cognitive dysfunction. However, incomplete or atypical clinical presentation has been previously reported, but in all these cases, the patients had at least one of the main clinical features of the disease (ophthalmoplegia, parkinsonian syndrome or cognitive dysfunction).

CASE REPORT

A 60-year-old woman presented with nocturnal agitation and choreiform movements. A few months later she developed severe swallowing disorders, caused by achalasia of the upper esophageal sphincter, and responsible for recurrent acute respiratory distress and pneumonia, prevailing to tracheotomy and gastrostomy. She died suddenly two years after the onset of the symptoms.

RESULTS

Postmortem examination of brain revealed a tauopathy, with deposition of abnormal phosphorylated tau in threads and in coiled-shaped as well as globose tangles in the brainstem, subthalamic nuclei and hippocampus. Nuclei of the medulla, including the vagus/solitarius complex and the region of the nucleus ambiguous were especially rich in tau positive inclusions. Ultrastructural analysis of globoid-shaped tangles in the brainstem revealed the presence of straight and paired helicoidal filaments compatible with a PSP.

CONCLUSIONS

This case contributes to improve knowledge of the clinical phenotypic range of PSP. In this case, the neuropathological lesions accounted for most of the symptoms. However, the early death of the patient was probably related to the particular distribution of the neuropathological lesions. This case suggests that the initial neuropathological changes in PSP is located in the dorsal brainstem.

Sleep disorders in Parkinson's disease: an overview

Sleep disturbances are one of the most common of the nonmotor complications of Parkinson's disease (PD), and increase in frequency with advancing disease. The causes of sleep disturbance in PD are numerous, and many patients may have several factors that contribute. These disorders can be broadly categorized into those that involve nocturnal sleep and daytime manifestations such as excessive daytime sleepiness. Some sleep disorders, in particular REM sleep behavior disorder (RBD) and excessive daytime sleepiness (EDS) may arise as a primary manifestation of PD, reflecting the anatomic areas affected by the neurodegenerative process. Appropriate diagnosis of the sleep disturbance affecting a PD patient can lead to specific treatments that can consolidate nocturnal sleep and enhance daytime alertness.

REM sleep behavior disorder in patients with guadeloupean parkinsonism, a tauopathy

STUDY OBJECTIVE

To describe sleep characteristics and rapid eye movement (REM) sleep behavior disorder in patients with Guadeloupean atypical parkinsonism (Gd-PSP), a tauopathy resembling progressive supranuclear palsy that mainly affects the midbrain. It is possibly caused by the ingestion of sour sop (corossol), a tropical fruit containing acetogenins, which are mitochondrial poisons.

DESIGN

Sleep interview, motor and cognitive tests, and overnight videopolysomnography.

PATIENTS

Thirty-six age-, sex-, disease-duration- and disability-matched patients with Gd-PSP (n = 9), progressive supranuclear palsy (a tauopathy, n = 9), Parkinson disease (a synucleinopathy, n = 9) and controls (n = 9).

SETTINGS

Tertiary-care academic hospital.

RESULTS

REM sleep behavior disorder was found in 78% patients with Gd-PSP (43% of patients reported having this disorder several years before the onset of parkinsonism), 44% of patients with idiopathic Parkinson disease, 33% of patients with progressive supranuclear palsy, and no controls. The percentage of muscle activity during REM sleep was greater in patients with Gd-PSP than in controls (limb muscle activity, 8.3%+/-8.7% vs 0.1%+/- 0.2%; chin muscle activity, 24.3%+/- 23.7% vs 0.7%+/-2.0%) but similar to that of other patient groups. The latency and percentage of REM sleep were similar in patients with Gd-PSP, patients with Parkinson disease, and controls, whereas patients with progressive supranuclear palsy had delayed and shortened REM sleep.

CONCLUSION

Although Gd-PSP is a tauopathy, most patients experience REM sleep behavior disorder. This suggests that the location of neuronal loss or dysfunction in the midbrain, rather than the protein comprising the histologic lesions (synuclein versus tau aggregation), is responsible for suppressing muscle atonia during REM sleep. Subjects with idiopathic REM sleep behavior disorder should avoid eating sour sop.

Rapid eye movement sleep parasomnias

The recognition of RBD has shed additional scientific light on the "bumps in the night"; expanded knowledge of states of being and state dissociation; opened up new areas of research on brain and mind dysfunction during sleep; expanded knowledge of various neurologic disorders, particularly narcolepsy and parkinsonism; and reaffirmed the vital link between basic research and clinical medicine. Moreover, the safe and effective treatment of RBD with clonazepam is especially gratifying.

Excessive daytime sleepiness in parkinsonism

Excessive daytime sleepiness (EDS) can affect 20-50% of patients with Parkinson's disease (PD), whereas sleep attacks (SA), which are sleep episodes without prodroma, seem infrequent. EDS is associated with more advanced disease, higher doses of levodopa-equivalent, and sometimes the use of dopamine agonists. Patients at risk for SA have higher Epworth sleepiness scores (ESS) (although an important subset of patients under-score on this scale) and a more frequent use of ergot or non-ergot dopamine agonists. Polysomnography is a valuable tool in patients with PD, because sleep apnea may occur in 20% of patients, whereas a specific narcolepsy-like phenotype, identified on multiple-sleep latency tests, occurs in patients with most severe EDS; this suggests a lesion in sleep-wake systems. Removal or replacement of a recently introduced dopamine agonist may offer some relief for EDS. If not, the adjunction of modafinil has a good benefit-risk ratio in patients with PD. EDS (and sometimes the narcolepsy-like phenotype) may also affect patients with atypical parkinsonism, such as dementia with Lewy bodies, multiple-system atrophy, and progressive supranuclear palsy.

Electroencephalogram in the dementia workup

Dementia is affecting an increasing proportion of the population in the developed world. It is important to reach a correct diagnosis of dementia, because this has implications on the treatment. The electroencephalogram (EEG) is, in general, not a sensitive test for detecting dementia and is not recommended in the standard workup of dementia. In spite of this, however, EEG is useful in patients with deteriorating mental status in whom dementia is suspected mainly to rule out delirium, depression, atypical complex partial seizures, and prion disease. An EEG also provides insight into the physiology of different dementia types. The EEG is most useful when interpreted within a well-defined clinical context, such as knowing the patient's degree of cognitive impairment. It is a noninvasive and inexpensive test, and the threshold should be low for ordering it. This article summarizes EEG findings with aging, different dementia types, and conditions masked as dementia.

Sleep and quantitative EEG in neurodegenerative disorders

This paper reviews current knowledge on sleep problems, sleep architecture changes and quantitative EEG alteration brought on by various neurodegenerative diseases, such as Alzheimer's disease (AD), progressive supranuclear palsy (PSP), REM sleep behavior disorder (RBD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy MSA, Huntington's disease and Creutzfeldt-Jakob disease, in comparison to normal aging. The study of sleep variables and that of the spectral composition of the EEG can provide valuable information for understanding the pathophysiology and for assisting the diagnosis of neurodegenerative diseases.

Slowing of electroencephalogram in rapid eye movement sleep behavior disorder

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by a loss of atonia and an increase in phasic muscle activity during REM sleep, leading to complex nocturnal motor behaviors. Brainstem structures responsible for the pathogenesis of RBD are also implicated in cortical activation. To verify the hypothesis that electroencephalogram (EEG) activation will be impaired in RBD, we performed quantitative analyses of waking and REM sleep EEG in 15 idiopathic RBD patients and 15 age- and gender-matched healthy subjects. During wakefulness, RBD patients showed a considerably higher theta power in frontal, temporal, and occipital regions with a lower beta power in the occipital region. The dominant occipital frequency was significantly lower in RBD. During REM sleep, beta power in the occipital region was lower in RBD. This study shows for the first time an impaired cortical activation during both wakefulness and REM sleep in idiopathic RBD, despite an absence of changes on sleep architecture compared with controls. EEG slowing in these patients may represent an early sign of central nervous system dysfunction, perhaps paralleled by subclinical cognitive deficits. The topographical distribution of EEG slowing and possible pathophysiological mechanisms are discussed in light of the known association between RBD and neurodegenerative disorders.

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 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.

Transcranial AC pulsed applications of weak electromagnetic fields reduces freezing and falling in progressive supranuclear palsy: a case report

Freezing is a common and disabling symptom in patients with Parkinsonism. It affects most commonly the gait in the form of start hesitation and sudden immobility often resulting in falling. A higher incidence of freezing occurs in patients with progressive supranuclear palsy (PSP) which is characterized clinically by a constellation of symptoms including supranuclear ophthalmoplegia, postural instability, axial rigidity, dysarthria, Parkinsonism, and pseudobulbar palsy. Pharmacologic therapy of PSP is currently disappointing and the disease progresses relentlessly to a fatal outcome within the first decade after onset. This report concerns a 67 year old woman with a diagnosis of PSP in whom freezing and frequent falling were the most disabling symptoms of the disease at the time of presentation. Both symptoms, which were rated 4 on the Unified Parkinson Rating Scale (UPRS) which grades Parkinsonian symptoms and signs from 0 to 4, with 0 being normal and 4 being severe symptoms, were resistant to treatment with dopaminergic drugs such as levodopa, amantadine, selegiline and pergolide mesylate as well as with the potent and highly selective noradrenergic reuptake inhibitor nortriptyline. Weekly transcranial applications of AC pulsed electromagnetic fields (EMFs) of picotesla flux density was associated with approximately 50% reduction in the frequency of freezing and about 80-90% reduction in frequency of falling after a 6 months follow-up period. At this point freezing was rated 2 while falling received a score of 1 on the UPRS. In addition, this treatment was associated with an improvement in Parkinsonian and pseudobulbar symptoms with the difference between the pre-and post EMF treatment across 13 measures being highly significant (p < .005; Sign test). These results suggest that transcranial administration AC pulsed EMFs in the picotesla flux density is efficacious in the treatment of PSP.