Sudden daytime sleep onset in Parkinson's disease: polysomnographic recordings

Melatonin Treatment for Sleep Disorders in Parkinson's Disease: A Meta-Analysis and Systematic Review

Objective

The efficacy of melatonin on sleep disorders in Parkinson's disease (PD) is still unclear. The purpose of this study was to investigate the efficacy of melatonin on sleep disorders in PD by summarizing evidence from randomized clinical trials (RCTs).

Methods

PubMed, Cochrane Library, EMBASE, and Web of Science databases were searched for studies published before 20 August 2021. Results were analyzed using Review Manager 5.2 software. We used Trial Sequential Analysis (TSA) software to avoid false-positive results caused by random errors.

Results

We included 7 studies in this systematic review and meta-analysis. The results of the meta-analysis showed that compared with placebo, the subjective sleep quality of patients with PD significantly improved after melatonin treatment (MD = −2.19, 95% CI: −3.53 to −0.86, P = 0.001). In the systematic review, we qualitatively analyzed the efficacy of melatonin on the objective sleep quality of patients with PD, and the results showed that melatonin exerted a positive effect with good safety and tolerability. However, there was no significant improvement in excessive daytime sleepiness assessed by the Epworth Sleepiness Scale (ESS).

Conclusion

We found that melatonin can significantly improve the subjective and objective sleep quality of patients with PD with good safety and tolerability. Melatonin could be considered an effective treatment for insomnia in patients with PD.

Excessive Daytime Sleepiness in Parkinson's Disease

Excessive daytime sleepiness (EDS) is one of the most common sleep disorders in Parkinson's disease (PD). It has attracted much attention due to high morbidity, poor quality of life, increased risk for accidents, obscure mechanisms, comorbidity with PD and limited therapeutic approaches. In this review, we summarize the current literature on epidemiology of EDS in PD to address the discrepancy between subjective and objective measures and clarify the reason for the inconsistent prevalence in previous studies. Besides, we focus on the effects of commonly used antiparkinsonian drugs on EDS and related pharmacological mechanisms to provide evidence for rational clinical medication in sleepy PD patients. More importantly, degeneration of wake-promoting nuclei owing to primary neurodegenerative process of PD is the underlying pathogenesis of EDS. Accordingly, altered wake-promoting nerve nuclei and neurotransmitter systems in PD patients are highlighted to providing clues for identifying EDS-causing targets in the sleep and wake cycles. Future mechanistic studies toward this direction will hopefully advance the development of novel and specific interventions for EDS in PD patients.

Orexinergic System in Neurodegenerative Diseases

Orexinergic system consisting of orexins and orexin receptors plays an essential role in regulating sleep–wake states, whereas sleep disruption is a common symptom of a number of neurodegenerative diseases. Emerging evidence reveals that the orexinergic system is disturbed in various neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and multiple sclerosis (MS), whereas the dysregulation of orexins and/or orexin receptors contributes to the pathogenesis of these diseases. In this review, we summarized advanced knowledge of the orexinergic system and its role in sleep, and reviewed the dysregulation of the orexinergic system and its role in the pathogenesis of AD, PD, HD, and MS. Moreover, the therapeutic potential of targeting the orexinergic system for the treatment of these diseases was discussed.

A review of automated sleep stage scoring based on physiological signals for the new millennia

BACKGROUND AND OBJECTIVE

Sleep is an important part of our life. That importance is highlighted by the multitude of health problems which result from sleep disorders. Detecting these sleep disorders requires an accurate interpretation of physiological signals. Prerequisite for this interpretation is an understanding of the way in which sleep stage changes manifest themselves in the signal waveform. With that understanding it is possible to build automated sleep stage scoring systems. Apart from their practical relevance for automating sleep disorder diagnosis, these systems provide a good indication of the amount of sleep stage related information communicated by a specific physiological signal.

METHODS

This article provides a comprehensive review of automated sleep stage scoring systems, which were created since the year 2000. The systems were developed for Electrocardiogram (ECG), Electroencephalogram (EEG), Electrooculogram (EOG), and a combination of signals.

RESULTS

Our review shows that all of these signals contain information for sleep stage scoring.

CONCLUSIONS

The result is important, because it allows us to shift our research focus away from information extraction methods to systemic improvements, such as patient comfort, redundancy, safety and cost.

Charting the onset of Parkinson-like motor and non-motor symptoms in nonhuman primate model of Parkinson's disease

Parkinson’s disease is a progressive neurodegenerative disease increasingly affecting our aging population. Remarkable advances have been made in developing novel therapies to control symptoms, halt or cure the disease, ranging from physiotherapy and small molecules to cell and gene therapy. This progress was enabled by the existence of reliable animal models. The nonhuman primate model of Parkinson’s disease emulates the cardinal symptoms of the disease, including tremor, rigidity, bradykinesia, postural instability, freezing and cognitive impairment. However, this model is established through the specific loss of midbrain dopaminergic neurons, while our current knowledge reflects the reality of Parkinson’s disease as a multisystem disease. Parkinson’s disease involves both motor and non-motor symptoms, such as sleep disturbance, olfaction, gastrointestinal dysfunctions, depression and cognitive deficits. Some of the non-motor symptoms emerge earlier at the prodromal phase and worsen with disease progression, yet in basic and translational studies, they are rarely considered as endpoints. In this study, we set to characterize an ensemble of less described motor and non-motor dysfunctions in the marmoset MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) model. We provide evidence that this animal model expresses postural head tremor and a progressive worsening of fine motor skills, movement coordination and cognitive abilities over a 6-month period. We report for the first time a non-invasive approach showing detailed analysis of daytime and nighttime sleep and circadian rhythm disturbance remarkably similar to Parkinson’s disease patients. This study describes the incidence of tremors, motor and non-motor dysfunctions in a preclinical model and highlights the need for their consideration in translating effective new therapeutic approaches for Parkinson’s disease.

A review of adverse events linked to dopamine agonists in the treatment of Parkinson's disease

INTRODUCTION

Dopamine agonists are highly effective as adjunctive therapy to levodopa in advanced Parkinson's disease. These drugs have rapidly gained popularity as a monotherapy in the early stages of Parkinson's disease for patients less than 65-70 years old since they are about as effective as levodopa but patients demonstrate a lower tendency to develop motor complications. However, dopamine agonists could have peripheral and central side-effects which are often the reason for the discontinuation of the treatment.

AREAS COVERED

This article presents an overview of the efficacy and the potential negative effects related to the use of dopamine agonists in the treatment of Parkinson's disease.

EXPERT OPINION

Beyond the new generation non ergot dopamine agonists, no strong evidences allow the choice of a specific dopamine agonists for Parkinson 's disease treatment and by now dopamine agonists treatment should be tailored on specific adverse events profile.

Progress in Clinical Neurosciences: A Forum on the Early Management of Parkinson's Disease

There are numerous concerns related to treatment choices involving early dopaminergic therapy in Parkinson's disease. These include the effect on the underlying progression of the neurodegenerative process as well as the development of motor complications such as fluctuations and dyskinesias. A number of recent basic and clinical studies have provided new insights but have also added confusion and controversy. This report summarizes presentations and discussion dealing with these issues from a one-day symposium involving Canadian Movement Disorders neurologists.

Sleep disturbances in Parkinson's disease: the contribution of dopamine in REM sleep regulation

Nearly all patients with Parkinson's disease (PD) have sleep disturbances. While it has been suggested that these disturbances involve a dopaminergic component, the specific mechanisms that contribute to this behavior are far from being fully understood. In this article, we have reviewed the current understanding of the linkage between sleep and PD, focusing on the participation of the dopaminergic system in the regulation of rapid eye movement (REM) sleep. The presence of an REM sleep behavior disorder in patients with PD might reflect the early involvement of dopaminergic neurotransmission in REM sleep-related structures. Therefore, it has been suggested that these structures are affected by an imbalance of dopamine levels. Several studies have demonstrated that neurons in the substantia nigra pars compacta (SNpc) and in the ventral tegmental area (VTA) are active during REM sleep and that sleep-related disturbances may result when these neurons are targeted by neurotoxins. We discuss current evidence suggesting the presence of a putative reciprocal connectivity between the SNpc, VTA, the pedunculopontine tegmental nucleus and reticular formation, which may exert an important influence on the REM sleep mechanism. This review provides a comprehensive overview of the literature that addresses this challenging and unrecognized component of PD.

Excessive daytime sleepiness in patients with Parkinson's disease

Excessive daytime sleepiness (EDS) is described as inappropriate and undesirable sleepiness during waking hours and is a common non-motor symptom in Parkinson's disease, affecting up to 50% of patients. EDS has a large impact on the quality of life of Parkinson's disease patients as well as of their caregivers, in some cases even more than the motor symptoms of the disease. Drug-induced EDS is a particular problem as many dopamine agonists used for the treatment of Parkinson's disease have EDS as an adverse effect. Dopaminergic treatment may also render a subset of Parkinson's disease patients at risk for sudden-onset sleep attacks that occur without warning and can be particularly hazardous if the patient is driving. This demonstrates the need for early recognition and management not only to increase health-related quality of life but also to ensure patient safety. There are many assessment tools for EDS, including the Epworth Sleepiness Scale (ESS) and the Multiple Sleep Latency Test (MSLT), although only the Parkinson's Disease Sleep Scale (PDSS) and the SCales for Outcomes in PArkinson's Disease-Sleep (SCOPA-S) are specifically validated for Parkinson's disease. Polysomnography can be used when necessary. Management comprises non-pharmacological and pharmacological approaches. Non-pharmacological approaches can be the mainstay of treatment for mild to moderate EDS. Advice on good sleep hygiene is instrumental, as pharmacological approaches have yet to provide consistent and reliable results without significant adverse effects. The efficacy of pharmacological treatment of EDS in Parkinson's disease using wakefulness-promoting drugs such as modafinil remains controversial. Further areas of research are now also focusing on adenosine A(2A) receptor antagonists, sodium oxybate and caffeine to promote wakefulness. A definitive treatment for the highly prevalent drug-induced EDS has not yet been found.

Tolcapone improves sleep in patients with advanced Parkinson's disease (PD)

Efficacy of the long-acting catechol-O-methyltransferase (COMT)-inhibitor, tolcapone on sleep quality was studied in 61 patients with advanced PD in a prospective open-label multicenter non-interventional trial. Main outcome measures were the PD sleep scale (PDSS). Further outcome measures were global clinical impression of change (GCI-C), daily off-time, activities of daily living (UPDRS part II), quality of life (EuroQoL-5D), Epworth sleepiness scale (ESS) and adverse events reports. All efficiency and safety parameters were assessed 4 weeks after the switch to tolcapone and compared to baseline. The mean±S.D. daily dose of tolcapone was 294.2±36.9 mg/day at the final assessment. The mean PDSS scores significantly improved from 21.6±8.1 at baseline to 16.3±7.7 at final assessment (p<0.0001). Consistently, daytime sleepiness was significantly reduced as reflected by lower scores on the ESS (p=0.0057). Further efficacy parameters including GCI-C, daily off-time, activities of daily living, and quality of life were also significantly improved. Tolcapone was in general well tolerated and safe. This observational study provides first evidence that tolcapone improves sleep quality and reduces daytime sleepiness in patients suffering from advanced PD.

Continuous sleep EEG monitoring in PD patients with and without sleep attacks

The pathogenesis of sleep attacks in Parkinson's disease (PD) is still unresolved. We investigated seven matched pairs of PD patients with and without a history of sleep attacks using continuous sleep EEG recording. According to the event marker altogether 12 sleep attacks were identified in three patients with a history of sleep attacks. All sleep attacks were characterized by NREM stage 1 and 2 sleep, whereas no sleep onset REM episodes were recorded. Five sleep attacks fulfilled our criteria for microsleep episodes lasting less than 120 s. The cumulative duration of microsleep episodes during the day was 27.7+/-20 min in patients with a history of sleep attacks vs. 6.4+/-4.1 min in patients without a history of sleep attacks (p=0.03), i.e., the majority of microsleep episodes were not perceived by the patients. In summary, our study suggests that sleep attacks are intrusions of NREM stage 1 and 2 sleep into wakefulness and can be identical to microsleep episodes. Future studies should systematically address the awareness of short sleep episodes in patients with PD and other disorders with increased daytime sleepiness.

The safety of dopamine agonists in the treatment of Parkinson's disease

Dopamine agonists are highly effective as adjunctive therapy to levodopa in advanced Parkinson's disease. These drugs have rapidly gained popularity as a monotherapy in the early stages of Parkinson's disease for patients < 65-70 years old, because they are about as effective as levodopa, but patients demonstrate a lower tendency to develop motor complications. However, dopamine agonists could have peripheral and central side effects, which are often the reason for the discontinuation of the treatment. This review focuses on the potential negative effects related to the use of dopamine agonists in the treatment of Parkinson's disease.

Current status of symptomatic medical therapy in Parkinson's disease

Symptomatic medical therapies for Parkinson's disease (PD) have been disease modifying and have led to improvement in daily function, quality of life, and survival. For 40 years, these therapies have been primarily dopaminergic, and currently include the dopamine (DA) precursor levodopa (LD), DA agonists, catechol-O-methyltransferase (COMT) inhibitors, and monoamine oxidase (MAO) inhibitors. The roles of all these classes of agents have evolved, with significant changes occurring since the early 2000s. This article reviews the current literature for each of these classes of drugs, with a focus on efficacy and place in the therapeutic scheme. Levodopa is no longer considered to be toxic and, thus, its early use is not only appropriate but recommended. Ergot agonists are no longer in use, and new agents administered in patch form or subcutaneous injections have been approved. The COMT inhibitor tolcapone, with its significant efficacy, has been reintroduced, and two new MAO inhibitors have been approved. Selected safety issues are discussed, including the incidence of melanoma in relation to LD; pathological gambling and DA agonists; hepatic toxicity of tolcapone; and the tyramine or so-called cheese reaction with MAO B inhibitors. The article closes with a discussion of future directions and new drugs under development.

Prodromal non-motor symptoms of Parkinson's disease

The motor symptoms of Parkinson's disease (PD), bradykinesia, muscular rigidity, and tremor depend upon degeneration of the dopaminergic neurons in the substantia nigra pars compacta. Recent neuropathological studies show that the Lewy bodies, the intraneuronal landmark of PD, accumulate in several neuronal cell types in the brain. An ascending gradient of pathological involvement, from the medulla oblongata to neocortical areas has been reported. Thus the original view of PD as a disease characterized by selective damage of the dopaminergic neurons in the mesencephalon should be updated into the concept of a severe multisystemic neurodegenerative disorder. Additionally, the neuropathological alterations outside the substantia nigra are soundly correlated with the non-motor symptoms of PD. As a result of these findings, interest is growing in the identification of prodromal non-motor symptoms of PD. Indeed, data from the literature suggest that autonomic disturbances, olfactory dysfunctions, depression and sleep disorders (in particular REM-sleep behavior disorder) may represent prodromal non-motor symptoms of PD. Several tests are available to detect most of these symptoms. Thus, the identification of prodromal non-motor symptoms may contribute to the precocious diagnosis of PD, and might be useful in the future to test the efficacy of neuroprotective agents.

Vigilance troubles in Parkinson's disease: A subjective and objective polysomnographic study

BACKGROUND AND PURPOSE

To assess the prevalence of vigilance disorders in Parkinson's disease patients, relate the observed phenomena to potential causes and confirm these troubles with polysomnographic analysis.

PATIENTS AND METHODS

A questionnaire was used to gather information on demographic data, previous and current treatments, disease characteristics, sleep and vigilance troubles. Somnolence was measured using the Epworth Sleepiness Scale (ESS). Nocturnal polysomnography (PSG) and multiple sleep latency tests (MSLT) were performed for a sample of parkinsonian patients.

RESULTS

Two hundred twenty-two parkinsonian patients completed the questionnaire, and 36 patients had objective analyses. Of the patients, 43.2% had an ESS score >10, and 28.4% reported somnolence in the hour after taking dopaminergic drugs, whereas 6.8% reported unintended sleep episodes. In view of questionnaire data, these vigilance disorders may be partly explained not only by the impact of nocturnal sleep disorders (e.g. sleep apnea syndromes) but also by dopaminergic therapy (especially with dopaminergic agonists). With PSG and MSLT results, we have shown a significant correlation between mean sleep latency and ESS score. Patients with unintended sleep episodes have severe sleepiness in MSLT compared with others patients.

CONCLUSIONS

Vigilance disorders are frequently observed in Parkinson's disease. We recommend informing patients of the risk of occurrence of such conditions, notably for patients with unintended sleep episodes and with sleepiness in the hour after taking dopaminergic drugs.

Excessive daytime sleepiness and unintended sleep in Parkinson's disease

Patients with Parkinson's disease and parkinsonian syndromes (eg, dementia with Lewy body disease, multisystem atrophy, and Shy-Drager syndrome) suffer from daytime sleepiness. This sleepiness is common and very real, often approaching levels observed in the prototypical disorder of sudden-onset sleep, namely narcolepsy/cataplexy. Physicians need to be vigilant in assessing parkinsonian patients for sleepiness because treatment can dramatically enhance quality of life and prevent the significant morbidity and mortality that attends daytime sleepiness. Male patients with advanced disease, cognitive impairment, drug-induced psychosis, and orthostatic hypotension are most at risk for developing pathologic sleepiness. Because primary sleep disorders can coexist with parkinsonism (eg, sleep apnea, insufficient or interrupted sleep), these potential causes should be carefully assessed with polysomnography and treated appropriately. Dopaminomimetics exacerbate sleepiness in a small subset of patients in a dose-dependent fashion. Nonetheless, the primary pathologies involved in parkinsonism appear to be the greatest contributors to daytime sleepiness. Sleepiness in parkinsonism, especially a narcolepsy-like phenotype, may necessitate treatment with wake-promoting agents such as bupropion, modafinil, or traditional psychostimulants.

Daytime sleep latency in medication-matched Parkinsonian patients with and without sudden onset of sleep

Currently, it is unclear whether sleep attacks in Parkinson's disease (PD) represent a novel entity or just a phenomenon of daytime sleepiness. We investigated 10 PD patients with sleep attacks and compared them with 10 PD patients without any daytime sleepiness. The patients were matched according to their dopaminergic medication and subjected to a sleep medical investigation. The mean sleep latency on the multiple sleep latency test was in the normal range and not significantly different between the groups. These data suggest that sleep attacks can occur against a background of normal alertness.

Non-motor symptoms of Parkinson's disease: diagnosis and management

The clinical diagnosis of Parkinson's disease rests on the identification of the characteristics related to dopamine deficiency that are a consequence of degeneration of the substantia nigra pars compacta. However, non-dopaminergic and non-motor symptoms are sometimes present before diagnosis and almost inevitably emerge with disease progression. Indeed, non-motor symptoms dominate the clinical picture of advanced Parkinson's disease and contribute to severe disability, impaired quality of life, and shortened life expectancy. By contrast with the dopaminergic symptoms of the disease, for which treatment is available, non-motor symptoms are often poorly recognised and inadequately treated. However, attention is now being focused on the recognition and quantitation of non-motor symptoms, which will form the basis of improved treatments. Some non-motor symptoms, including depression, constipation, pain, genitourinary problems, and sleep disorders, can be improved with available treatments. Other non-motor symptoms can be more refractory and need the introduction of novel non-dopaminergic drugs. Inevitably, the development of treatments that can slow or prevent the progression of Parkinson's disease and its multicentric neurodegeneration provides the best hope of curing non-motor symptoms.

Parkinson's disease and sleep

Sleep disorders are common in PD and many factors can contribute to disturbed nocturnal sleep and daytime sleepiness. Factors contributing to sleep disturbance include the presence of insomnia, mood or anxiety disorders, dementia, specific sleep disorders, PD motor disorders, and the effects of PD or medications. Patients who have PD should be interrogated about sleep disturbance and daytime sleepiness and preferably, because of underestimation of the severity of sleepiness or lack of awareness, patients should be interviewed in the presence of a close friend or relative. The ability to drive, if sleepiness is present, should be assessed and appropriate recommendations made. Treatment of sleepiness involves treating any underlying sleep disturbance and may involve the use of stimulant or alerting medications in the daytime.

Modafinil for daytime somnolence in Parkinson's disease: double blind, placebo controlled parallel trial

BACKGROUND

Excessive daytime somnolence (EDS) commonly complicates Parkinson's disease (PD). The aetiology of EDS is probably multifactorial but is probably exacerbated by dopaminergic medications. Modafinil is a wake-promoting agent approved for use in narcolepsy, but it is often used to treat a variety of somnolent conditions.

METHOD

A double blind, placebo controlled parallel design trial was conducted to assess the efficacy of modafinil (200-400 mg/day) for the treatment of EDS in PD. The primary efficacy measure was the Epworth Sleepiness (ES) scale score. Secondary efficacy points included the Unified Parkinson's Disease Rating Scale (UPDRS), the Fatigue Severity Scale, the Hamilton Depression Scale, and the multiple sleep latency test (MSLT).

RESULTS

Of a total of 40 subjects (29 men, mean (SD) age 64.8 (11.3) years), randomised to modafinil or placebo, 37 completed the study. Modafinil failed to significantly improve ES scores compared with placebo (2.7 v 1.5 points improvement, respectively, p = 0.28). MSLT failed to improve with modafinil relative to placebo (-0.16 v -0.70, respectively, p = 0.14). UPDRS, global impressions, Fatigue Severity Scale, and Hamilton Depression Scale scores were unchanged. Adverse events were minimal.

CONCLUSION

Modafinil failed to significantly improve EDS in PD compared with placebo. The drug did not alter motor symptoms in PD and was well tolerated.

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.

Driving in Parkinson's disease: Mobility, accidents, and sudden onset of sleep at the wheel

Only few studies have addressed driving ability in Parkinson's disease (PD) to date. However, studies investigating accident proneness of PD patients are urgently needed in the light of motor disability in PD and--particularly--the report of "sleep attacks" at the wheel. We sent a questionnaire about sudden onset of sleep (SOS) and driving behavior to 12,000 PD patients. Subsequently, of 6,620 complete data sets, 361 patients were interviewed by phone. A total of 82% of those 6,620 patients held a driving license, and 60% of them still participated in traffic. Of the patients holding a driving license, 15% had been involved in and 11% had caused at least one accident during the past 5 years. The risk of causing accidents was significantly increased for patients who felt moderately impaired by PD, had an increased Epworth Sleepiness Scale (ESS) score, and had experienced SOS while driving. Sleep attacks at the wheel usually occurred in easy driving situations and resulted in typical fatigue-related accidents. Those having retired from driving had a more advanced (subjective) disease severity, higher age, more frequently female gender, an increased ESS score, and a longer disease duration. The study revealed SOS and daytime sleepiness as critical factors for traffic safety in addition to motor disabilities of PD patients. The results suggest that real sleep attacks without any prior sleepiness are rare. However, our data underline the importance of mobility for patients and the need for further studies addressing the ability to drive in PD.

Sleep episodes and daytime somnolence as result of individual susceptibility to different dopaminergic drugs in a PD patient: a polysomnographic study

The association between excessive daytime somnolence (EDS) and idiopathic Parkinson's disease (PD) is often reported but still debated. The possible role of antiparkinsonian therapy or primarily of PD on excessive diurnal sleepiness is controversial. We describe the case of a 61-year-old patient affected by PD who experienced sleep episodes (SE) occurring during pramipexole plus L-Dopa therapy. Polysomnographic sleep studies and subjective evaluations of daytime sleepiness (Epworth Sleepiness Scale) were carried out under administration of pramipexole plus L-Dopa, L-Dopa monotherapy and cabergoline plus L-Dopa. The polysomnography revealed two sleep events during pramipexole plus L-Dopa. Moreover, the polysomnographic data showed an increase of both diurnal and nocturnal sleep under pramipexole plus L-Dopa compared with cabergoline plus L-Dopa and L-Dopa as monotherapy. In addition, while Epworth Sleepiness Scale (ESS) Score showed a mild sleepiness under pramipexole (ESS score=11), ESS scores were normal under both L-Dopa and cabergoline plus L-Dopa. Sleep episodes also disappeared under both L-Dopa and cabergoline plus L-Dopa (2- and 12-month follow-up). We hypothesize that an individual susceptibility to specific antiparkinsonian drug may play a significant role in the genesis of sleepiness in our PD patient.

Predictors of sudden onset of sleep in Parkinson's disease

With respect to the ongoing discussion of "sleep attacks" in Parkinson's disease (PD), we sought to estimate the prevalence of sudden onset of sleep (SOS) with and without preceding sleepiness in PD, to identify associated factors, and to define the role of antiparkinsonian medication in SOS. We sent a questionnaire about SOS, sleep behaviour, and medication to 12,000 PD patients. The response rate was 63%, from which 6,620 complete data sets could be analysed. A total of 42.9% of our population reported SOS, 10% of whom never experienced sleepiness before the appearance of SOS (4.3% of all), and we identified the administration of all dopaminergic drugs as a risk factor for SOS. However, SOS occurred earlier after introduction of nonergoline dopamine agonists (DA) and was more strongly associated with nonergoline DA in younger patients (below 70 years) with a shorter disease duration (up to 7 years) but, actually, medication was less efficient in predicting SOS than most other factors considered such as higher age, male sex, longer disease duration, and the report of sleep disturbances. This survey strongly suggests that SOS is a multifactorial phenomenon. Some subgroups are at particular risk of experiencing SOS under nonergoline DA, especially at the beginning of this therapy. Our results support the current notion that SOS, in part, can be attributed to PD-specific pathology because disease duration and subjective disease severity have been shown to be predictors of SOS. We recommend the development of a standardised question to recognise SOS and to facilitate the comparison of prevalence estimates.

Comparing dopamine agonists in Parkinsonʼs disease

Dopamine agonists are effective in the management of both advanced and early-stage Parkinson's disease. Unfortunately, randomized head-to-head comparative studies between the many different dopamine agonists now available are sparse. Indirect comparisons of dopamine agonists show that ergot derivatives, such as pergolide and cabergoline, are as effective as non-ergot derivatives, such as ropinirole and pramipexole, in ameliorating Parkinson's disease symptoms in patients in early or advanced stages of the condition. As far as safety and tolerability are concerned, no significant differences between dopamine agonists are found. However, some specific adverse events, such as somnolence and sleep attacks, seem less frequent in monotherapy studies with pergolide than in those with the non-ergot dopamine agonists; however, because of the lack of direct-comparison studies this cannot be proved conclusively. Randomized, controlled comparative studies between dopamine agonists are necessary to verify any possible differences in their effectiveness and tolerability in the treatment of Parkinson's disease.

Sleep attacks and dopamine agonists for Parkinson's disease: what is currently known?

The aetiology of sleep disturbances in patients with Parkinson's disease is multifactorial. Medications, the disease process and underlying sleep disorders may contribute to sleepiness in patients with the disease. Somnolence, excessive daytime sleepiness and sleep attacks appear to be more common in patients with Parkinson's disease who are treated with dopamine receptor agonists than in those who are treated with other antiparkinsonian agents, although virtually all dopaminergic antiparkinsonian medications may contribute to sleepiness. Somnolence caused by dopamine agonists may be dose related and occurs most frequently during the dose-escalation phase. Somnolence may also emerge or worsen after a period of time on a stable dose. Patients with Parkinson's disease and caregivers should be informed about the risk of sleepiness and sleep attacks associated with dopaminergic medications and the potential implications for driving safety.

Sleep attacks, daytime sleepiness, and dopamine agonists in Parkinson's disease

To study the putative association of dopamine agonists with sleep attacks in patients with Parkinson's disease (PD) and their relation to daytime sleepiness, we performed a survey of 2,952 PD patients in two German counties. In 177 patients, sudden, unexpected, and irresistible sleep episodes while engaged in some activity were identified in a structured telephone interview. Ninety-one of these patients denied the occurrence of appropriate warning signs. A total of 133 patients (75%) had an Epworth Sleepiness Scale (ESS) score >10; 65 (37%) >15. Thirty-one patients (18%) had an ESS score < or =10 and yet experienced sleep attacks without warning signs. Thus, although a significant proportion of patients at risk for sleep attacks might be identified using the ESS, roughly 1% of the PD patient population seems to be at risk for sleep attacks without appropriate warning signs and without accompanying daytime sleepiness. Sleep attacks occurred with all dopamine agonists marketed in Germany (alpha-dihydroergocryptine, bromocriptine, cabergoline, lisuride, pergolide, pramipexole, ropinirole), and no significant difference between ergot and nonergot drugs was evident. Levodopa (L-dopa) monotherapy carried the lowest risk for sleep attacks (2.9%; 95% confidence interval [CI], 1.7-4.0%) followed by dopamine agonist monotherapy (5.3%; 95% CI, 1.5-9.2%) and combination of L-dopa and a dopamine agonist (7.3%; 95% CI, 6.1-8.5%). Neither selegeline nor amantadine or entacapone appeared to influence the occurrence of sleep attacks. A high ESS score, intake of dopamine agonists, and duration of PD were the main influencing factors for the occurrence of sleep attacks. The odds ratio for dopamine agonist therapy was 2.9 compared to 1.9 with L-dopa therapy and 1.05 for a 1-year-longer disease duration.

Sleepiness in Parkinson's disease: a controlled study

Sudden-onset sleep episodes while driving have been reported in Parkinson's disease (PD) patients, and termed sleep attacks because they were reported to be irresistible and to occur without warning. We postulate that these episodes are due to excessive daytime sleepiness secondary to the high frequency of sleep disorders in PD patients and the sedative effects of dopaminergic medications. We assessed the frequency and relationship between excess daytime sleepiness and sleep episodes while driving (SE) in patients with PD. We evaluated 101 consecutive PD patients presenting to the Movement Disorder Center at the Mount Sinai School of Medicine using a questionnaire that incorporated a subjective estimate of sleepiness, the Epworth Sleepiness Scale (ESS) and information on disease severity and dopaminergic medications. One hundred age-matched respondents without PD served as a control population. Excess daytime sleepiness was reported in 76% of PD patients compared to 47% of controls (P < 0.05). The mean ESS scores for PD patients was 9.1 +/- 6.1 versus 5.7 +/- 4.4 in controls (P < 0.001). ESS scores > or =10 were observed in 40.6% of PD patients compared to 19% of controls (P < 0.01) and 24% of PD patients had scores > or =15, compared to 5% of controls (P < 0.001). Sleep episodes while driving were experienced by 20.8% of PD drivers compared to 6% of control drivers (P < 0.05). The mean daily levodopa (L-dopa) dose equivalent was 1,142 +/- 858 mg in PD drivers who experienced a SE while driving compared to 626 +/- 667 mg in those who had not (P < 0.05). Similarly, ESS was significantly greater in drivers with a SE than in those without (11.6 +/- 6.4 vs. 8.4 +/- 4.1; P < 0.05). Logistic regression analysis demonstrated that ESS and mean daily L-dopa dose equivalents were predictors of sleep episodes while driving, whereas age, gender, disease severity, and individual dopaminergic agents were not. These findings support the notion that sleep episodes while driving in PD patients are related to excess daytime sleepiness and dopaminergic load. Physicians should advise and treat patients accordingly.

Sleep disorders in Parkinson's disease: epidemiology and management

Sleep problems are an under-emphasised cause of disability in Parkinson's disease (PD) and may be seen independently of PD, associated with primary PD pathology, or as a result of antiparkinsonian medications. Common sleep disorders include excessive daytime sleepiness, rapid eye movement (REM) sleep behaviour disorder, night-time wakefulness and restless legs syndrome. A number of strategies may be used to improve sleep cycle disturbances, and often these interventions do not require pharmacological manipulation. Restoring traditional mealtimes and scheduling activities during predicted periods of sleepiness may help alleviate daytime somnolence; the use of controlled-release levodopa preparations or administration of a catechol-O-methyl transferase (COMT) inhibitor with levodopa at bedtime may reduce periods of night-time wakefulness. Administration of clonazepam at bedtime may assist with REM sleep behaviour disorder but, because this agent can result in daytime somnolence, experimentation with dosage times is recommended. Sleep attacks are described as a sudden, unavoidable transition from wakefulness to sleep and, although rare, have been described with pramipexole, ropinirole and other dopamine agonists. Although the condition has yet to be recognised by the International Association of Sleep Disorders, patients with PD who report rapid sleep onset should be evaluated for the possibility of sleep attacks. If sleep attacks are suspected, it is reasonable to strongly caution patients regarding potentially risk-associated activities such as driving, and to consider careful withdrawal of dopaminergic therapy.

Excessive daytime sleepiness and levodopa in Parkinson's disease: polygraphic, placebo-controlled monitoring

The authors performed 72-hour polysomnography, including a levodopa-placebo-controlled choice reaction time test with continuous monitoring of cardiovascular variables in two patients with Parkinson's disease complaining of excessive daytime sleepiness on levodopa monotherapy. The subacute levodopa challenge was accompanied by physiologic sleep episodes, worsened reaction times, and a reduction in mean blood pressure and heart rate over baseline values, linked temporally to the sleep episodes.

Sleepiness and Unintended Sleep in Parkinson's Disease

Patients with Parkinson's disease (PD) and parkinsonian syndromes (eg, dementia with Lewy bodies, multisystem atrophy, and Shy-Drager syndrome) suffer from daytime sleepiness. Sleepiness in PD is common (10% to 50% of patients) and very real, often approaching levels observed in the prototypical disorder of sudden-onset sleep, viz, and narcolepsy with cataplexy. Physicians need to be vigilant in assessing parkinsonian patients for sleepiness, because treatment can dramatically enhance quality of life and prevent the significant morbidity and mortality that attends daytime sleepiness. Men with advanced disease, cognitive impairment, drug-induced psychosis, and orthostatic hypotension are most at risk for developing pathologic sleepiness. Because primary sleep disorders can coexist with Parkinsonism (eg, sleep apnea, insufficient or interrupted sleep), these potential causes should be carefully assessed with polysomnography and treated appropriately. Dopaminomimetics may exacerbate sleepiness in a small subset of patients. The primary pathologies involved in Parkinsonism appear to be the greatest contributors to the development of daytime sleepiness. Sleepiness in Parkinsonism, especially a narcolepsy-like phenotype, may necessitate treatment with wake-promoting agents, such as bupropion, modafinil, or traditional psychostimulants.

Randomized trial of modafinil for treating subjective daytime sleepiness in patients with Parkinson's disease

We assessed the safety and efficacy of modafinil for the treatment of excessive daytime sleepiness in patients with Parkinson's disease (PD). This was a single-site, randomized, double-blind, placebo-controlled crossover study of 21 PD patients having an Epworth Sleepiness Scale (ESS) score > or =10. They received either placebo or modafinil 200 mg/day for 3 weeks, followed by a washout week, then the alternate treatment for 3 weeks. The ESS data demonstrated a carryover effect, so the changes from baseline ESS scores were compared between the two treatments for period 1 only. The ESS scores for the placebo group went from 16.0 +/- 4.2 (mean +/- SD) to 17.0 +/- 5.1 and for the modafinil group went from 17.8 +/- 4.2 to 14.4 +/- 5.7 (P = 0.039). There was no significant carryover effect for any other measure. The patient Clinical Global Impression of Change (+3 to -3) improved by 0.75 on modafinil compared with 0.15 for placebo (P = 0.07). A total of 7 of 20 (35%) of the patients reported some improvement on modafinil but not placebo. There was no significant improvement or worsening of the UPDRS subscores I-III, Timed Tap test, or time on. Vital signs, electrocardiograms, and lab tests were unchanged. Modafinil was very well tolerated. Our data demonstrate that, in a small sample size, administration of 200 mg/day of modafinil was associated with few side effects and was modestly effective for the treatment of excessive daytime sleepiness in patients with PD.

Sleep disturbances in Parkinson's disease

Disorders of sleep and daytime alertness are frequent in Parkinson's disease patients and arise from a number of diverse factors. The most common complaint of night-time sleep disturbance in Parkinson's disease is sleep fragmentation. Sleep fragmentation can be associated with recurrent parkinsonian symptoms, the effect of medications, concomitant medical disorders such as nocturia, or psychiatric disorders such as depression or anxiety. Likewise, nocturnal sleep disturbance may arise from sleep apnea, periodic limb movements of sleep, or rapid eye movement (REM) sleep behavior disorder. Nocturnal sleep deprivation may lead to excessive daytime sleepiness. Other potential sources of daytime sleepiness include the effects of medications or disruption of central sleep mechanisms due to the pathologic processes of Parkinson's disease itself. Diagnosis of sleep disturbances and daytime sleepiness requires a direct interview of the patient and the caregiver, and may involve consultation with the sleep specialist or medical physician. Treatment is aimed toward improving night-time sleep and daytime drowsiness by addressing the causative factors.

Sleep attacks in Parkinson's disease induced by Entacapone, a COMT-inhibitor

We present a patient who suffered from sleep attacks after starting entacapone in addition to levodopa. Entacapone, a catechol-O-methyl transferase inhibitor, alters the pharmacokinetics of levodopa, leading to increase of levodopa concentration in plasma and brain. This mechanism is suspected to be involved in the pathophysiology of sleep attacks in this case.

The management of patients with early Parkinson's disease

A major problem in the management of early Parkinson's disease is to choose the first medication to prescribe. This decision should rely on the level of available clinical evidence, largely based, at least for efficacy, on the results of randomised clinical trials. Safety and costs are also crucial to consider. Other factors like for example pathophysiological concepts, individual experience, marketing pressure, socio-economical environment, patients needs and expectations have, however, also their own influence. Levodopa is efficacious and cheap, but induces long-term motor complications. The early use of dopamine agonists is more and more frequently promoted, because large prospective L-dopa-controlled trials demonstrated that this strategy reduces the risk of such long-term complications. Integrating individual clinical expertise to the best available external clinical evidence (evidence-based medicine) is the best strategy in making decisions about the care of individual patients.

Treatment interventions for Parkinson's disease: an evidence based assessment

We did a systematic review, with a uniform method of assessment of efficacy and safety, to assess the different interventions available for the management of Parkinson's disease (drugs, surgical interventions, and physical treatments) with respect to the following indications: prevention of disease progression, symptomatic treatment of motor features (parkinsonism), symptomatic control of motor complications, prevention of motor complications, and symptomatic treatment of non-motor features. Our aim was not to define practice guidelines, but rather to improve clinicians' knowledge of the presently available published clinical evidence, based mainly on randomised controlled trials. We hope that our review will help doctors to incorporate this background into their own decision-making strategy to make appropriate choices with respect to the treatment of individual patients with Parkinson's disease.

Evaluation of sleep and driving performance in six patients with Parkinson's disease reporting sudden onset of sleep under dopaminergic medication: a pilot study

Six patients with Parkinson's disease (PD) reporting unusually fast or sudden onset of sleep under the addition of dopamine agonists to a previous levodopa-containing therapy were examined using a sleep-wake diary, the Epworth sleepiness scale (ESS), polysomnography, multiple sleep latency tests (MSLT), a standardized vigilance test, and driving simulation. In all patients, ESS scores were increased and polysomnography showed disruption of the sleep pattern, a tendency towards poor sleep efficiency, and reduced proportions of slow- wave and rapid eye movement sleep. Pathological results in the MSLT or the vigilance test were obtained in five cases. For evaluation of driving performance, the standard deviation from the mean lane position during driving simulation was calculated. Three of five patients had clearly increased mean SDLP values. With respect to the measurement of daytime sleepiness (ESS, MSLT, vigilance test, and driving simulation), each patient had pathological results in at least two of these examinations. However, only a limited transfer of the routine vigilance assessment to driving performance was possible. In summary, this pilot study indicates that unusually fast or sudden onset of sleep in PD patients is a phenomenon of daytime sleepiness.