Sleep episodes in Parkinson's disease: a wake-up call

Management of Sleep Disturbances in Parkinson's Disease

Parkinson's disease (PD) is defined by its motor symptoms rigidity, tremor, and akinesia. However, non-motor symptoms, particularly autonomic disorders and sleep disturbances, occur frequently in PD causing equivalent or even greater discomfort than motor symptoms effectively decreasing quality of life in patients and caregivers. Most common sleep disturbances in PD are insomnia, sleep disordered breathing, excessive daytime sleepiness, REM sleep behavior disorder, and sleep-related movement disorders such as restless legs syndrome. Despite their high prevalence, therapeutic options in the in- and outpatient setting are limited, partly due to lack of scientific evidence. The importance of sleep disturbances in neurodegenerative diseases has been further emphasized by recent evidence indicating a bidirectional relationship between neurodegeneration and sleep. A more profound insight into the underlying pathophysiological mechanisms intertwining sleep and neurodegeneration might lead to unique and individually tailored disease modifying or even neuroprotective therapeutic options in the long run. Therefore, current evidence concerning the management of sleep disturbances in PD will be discussed with the aim of providing a substantiated scaffolding for clinical decisions in long-term PD therapy.

Management of sleep disorders in Parkinson's disease and multiple system atrophy

Parkinson's disease (PD) and multiple system atrophy (MSA) are disorders associated with α synuclein-related neurodegeneration. Nonmotor symptoms are common hallmarks of these disorders, and disturbances of the sleep-wake cycle are among the most common nonmotor symptoms. It is only recently that sleep disturbances have received the attention of the medical and research community. Significant progress has been made in understanding the pathophysiology of sleep and wake disruption in alphasynucleinopathies during the past few decades. Despite these advancements, treatment options are limited and frequently associated with problematic side effects. Further studies that center on the development of novel treatment approaches are very much needed. In this article, the author discusses the current state of the management of disturbed sleep and alertness in PD and MSA. © 2017 International Parkinson and Movement Disorder Society.

Circadian melatonin rhythm and excessive daytime sleepiness in Parkinson disease

IMPORTANCE

Diurnal fluctuations of motor and nonmotor symptoms and a high prevalence of sleep-wake disturbances in Parkinson disease (PD) suggest a role of the circadian system in the modulation of these symptoms. However, surprisingly little is known regarding circadian function in PD and whether circadian dysfunction is involved in the development of sleep-wake disturbances in PD.

OBJECTIVE

To determine the relationship between the timing and amplitude of the 24-hour melatonin rhythm, a marker of endogenous circadian rhythmicity, with self-reported sleep quality, the severity of daytime sleepiness, and disease metrics.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study from January 1, 2009, through December 31, 2012, of 20 patients with PD receiving stable dopaminergic therapy and 15 age-matched control participants. Both groups underwent blood sampling for the measurement of serum melatonin levels at 30-minute intervals for 24 hours under modified constant routine conditions at the Parkinson's Disease and Movement Disorders Center of Northwestern University.

INTERVENTIONS

Twenty-four hour monitoring of serum melatonin secretion.

MAIN OUTCOMES AND MEASURES

Clinical and demographic data, self-reported measures of sleep quality (Pittsburgh Sleep Quality Index) and daytime sleepiness (Epworth Sleepiness Scale), and circadian markers of the melatonin rhythm, including the amplitude, area under the curve (AUC), and phase of the 24-hour rhythm.

RESULTS

Patients with PD had blunted circadian rhythms of melatonin secretion compared with controls; the amplitude of the melatonin rhythm and the 24-hour AUC for circulating melatonin levels were significantly lower in PD patients (P < .001). Markers of the circadian phase were not significantly different between the 2 groups. Compared with PD patients without excessive daytime sleepiness, patients with excessive daytime sleepiness (Epworth Sleepiness Scale score ≥10) had a significantly lower amplitude of the melatonin rhythm and 24-hour melatonin AUC (P = .001). Disease duration, Unified Parkinson's Disease Rating Scale scores, levodopa equivalent dose, and global Pittsburgh Sleep Quality Index score in the PD group were not significantly related to measures of the melatonin circadian rhythm.

CONCLUSIONS AND RELEVANCE

Circadian dysfunction may underlie excessive sleepiness in PD. The nature of this association needs to be explored further in longitudinal studies. Approaches aimed to strengthen circadian function, such as timed exposure to bright light and exercise, might serve as complementary therapies for the nonmotor manifestations of PD.

Dopamine agonists in the treatment of Parkinson’s disease

Dopamine agonists are highly effective as adjunctive therapy to levodopa in advanced Parkinson's disease and have rapidly gained popularity as a monotherapy in the early stages of Parkinson's disease for patients less than 65-70 years old. In the latter case, dopamine agonists are about as effective as levodopa but patients demonstrate a lower tendency to develop motor complications. However, dopamine agonists lose efficacy over time and the number of patients remaining on agonist monotherapy decreases to less than 50% after 3 years of treatment. Thus, after a few years of treatment the majority of patients who started on dopamine agonists will be administered levodopa, in a combined dopaminergic therapy, in order to achieve a better control of motor symptoms.

Treatment of advanced Parkinson’s disease

Parkinson's disease is a progressive neurological disorder characterized by tremor, bradykinesia, rigidity, gait and postural instability and a variety of nonmotor symptoms. While these and other motor signs typically improve with levodopa, the so-called axial signs, such as dysarthria, dysphagia, postural instability and freezing, and most nonmotor signs, such as depression, cognitive decline and dysautonomia, usually do not respond satisfactorily to levodopa. Furthermore, the use of levodopa may be limited by the development of motor fluctuations, dyskinesias and other adverse effects. This manuscript reviews the medical management of advanced Parkinson's disease, focusing on the treatment of motor fluctuations and dyskinesias and of nonmotor and nonlevodopa responsive symptoms.

Nonmotor symptoms of Parkinson’s disease

Nonmotor symptoms occur commonly in Parkinson's disease (PD) patients and are frequently under-recognized and undertreated. Symptoms include sleep abnormalities, fatigue, autonomic disturbances, mood disorders and cognitive dysfunction. Early recognition and treatment of nonmotor symptoms in PD is critical to providing optimal management. A new screening questionnaire and the revised Unified PD Rating Scale should assist healthcare providers to better identify and evaluate these symptoms. This article reviews the identification and treatment of nonmotor symptoms in PD.

Role of dopamine receptor agonists in the treatment of early Parkinson's disease

In the last two decades, the usefulness of dopamine receptor agonists in the symptomatic treatment of Parkinson' disease (PD) has been demonstrated in many randomized controlled clinical trials. The initial role of such compounds as an adjunctive therapy to L-dopa to improve motor fluctuations has now expanded to the treatment of early PD as initial monotherapy. The rationale for the use of dopamine receptor agonists in early disease is to delay or reduce the incidence of motor complications resulting from long-term L-dopa therapy, probably by virtue of less pulsatile stimulation of postsynaptic dopamine receptors. Indeed, controlled trials with both ergot and non-ergot dopamine receptor agonists, such as cabergoline, pergolide, pramipexole and ropinirole, have shown lower risk of motor fluctuations and dyskinesias than with L-dopa, when used as monotherapy in early PD patients. The benefit of agonists in preventing motor complications is, however, balanced by a smaller effect on motor symptoms compared with L-dopa. Moreover, a greater incidence of side-effects, particularly somnolence, hallucinations and leg oedema, occurs with dopamine receptor agonists. Because of the risk of fibrotic reactions, ergot derivatives (bromocriptine, cabergoline, and pergolide) are not recommended as first-line antiparkinsonian medication. In younger patients, who are usually more prone to developing L-dopa-induced motor complications, the initial treatment with dopamine receptor agonists can be recommended. Further pharmacological refinement of PD management with these drugs may result from new formulations of old drugs, such as once-daily prolonged-release ropinirole, or new agonists, such as the rotigotine patch, that can allow more continuous dopaminergic stimulation and improve patient compliance with the drug treatment. Theoretically, another advantage of dopamine receptor agonists is the potential for a neuroprotective effect, through many different mechanisms of actions. Preliminary controlled trials with pramipexole and ropinirole, although encouraging, did not provide conclusive proof of the disease-modifying effect of dopamine receptor agonists; large controlled clinical trials are now underway and results are expected soon.

Is obstructive sleep apnea a problem in Parkinson's disease?

BACKGROUND

Parkinson's disease (PD) is associated with sleep disorders and daytime sleepiness. Upper airway dysfunction in PD may promote obstructive sleep apnea. However, the frequency and clinical relevance of sleep-disordered breathing in PD remains unclear.

METHODS

Sleep apnea symptoms, cardiovascular events and treatment were collected in 100 patients with PD (50 unselected, consecutive patients matched for age, sex and body mass index with 50 patients referred for sleepiness) and 50 in-hospital controls. The motor and cognitive status was evaluated in patients with PD. The 150 subjects underwent a video-polysomnography.

RESULTS

Sleep apnea (defined as an apnea-hypopnea index greater than 5) was less frequent in the PD group (27% patients, including 6% with mild, 11% with moderate and 10% with severe sleep apnea) than in the control group (40% in-hospital controls, p<0.002). Sleep apnea was not associated with increased sleepiness, nocturia, depression, cognitive impairment and cardiovascular events in patients with PD. Sleep apnea was more frequent and severe in the most disabled patients. Patients with PD did not display sleep hypoventilation, stridor and abnormal central sleep apnea. In patients with REM sleep behavior disorders, snoring and obstructive sleep apnea occurred during REM sleep, although the chin muscle tone was maintained.

CONCLUSION

Obstructive sleep apnea does not seem to be a clinically relevant issue in PD. Daytime sleepiness, nocturia and cognitive impairment are mostly caused by other, non-apneic mechanisms. The maintenance of chin muscle tone during REM sleep behavior disorder has no influence on the frequency of apneic events.

Sleep disorders in Parkinson's disease

Sleep disorders occur commonly in Parkinson's disease (PD), and reduce quality of life. Sleep-related problems in PD include insomnia, restless legs syndrome, rapid eye movement sleep behavior disorder, sleep apnea, parasomnias, excessive daytime sleepiness, and sleep attacks. This article reviews sleep disorders and their treatment in PD.

The involvement of dopamine in the modulation of sleep and waking

Dopamine (DA)-containing neurons involved in the regulation of sleep and waking (W) arise in the ventral tegmental area (VTA) and the substantia nigra pars compacta (SNc). The VTA and SNc cells have efferent and afferent connections with the dorsal raphe nucleus (DRN), the pedunculopontine and laterodorsal tegmental nuclei (PPT/LDT), the locus coeruleus (LC), the lateral and posterior hypothalamus (LH), the basal forebrain (BFB), and the thalamus. Molecular cloning techniques have enabled the characterization of two distinct groups of DA receptors, D(1)-like and D(2)-like receptors. The D(1) subfamily includes the D(1) and D(5) receptors, whereas the D(2) subfamily comprises the D(2), D(3), and D(4) receptors. Systemic administration of a selective D(1) receptor agonist induces behavioral arousal, together with an increase of W and a reduction of slow wave sleep (SWS) and REM sleep (REMS). Systemic injection of a DA D(2) receptor agonist induces biphasic effects, such that low doses reduce W and increase SWS and REMS (predominant activation of the D(2) autoreceptor), whereas large doses induce the opposite effect (predominant facilitation of the D(2) postsynaptic receptor). Compounds with DA D(1) or D(2) receptor blocking properties augment non-REMS and reduce W. Preliminary findings tend to indicate that the administration of a DA D(3)-preferring agonist induces somnolence and sleep in laboratory animals and man. DA neurons in the VTA and the SNc do not change their mean firing rate across the sleep-wake cycle. It has been proposed that DA cells in the midbrain show a change in temporal pattern rather than firing rate during the sleep-wake cycle. The available evidence tends to indicate that during W there occurs an increase of burst firing activity of DA neurons, and an enhanced release of DA in the VTA, the nucleus accumbens (NAc), and a number of forebrain structures. A series of structures relevant for the regulation of the behavioral state, including the DRN, LDT/PPT, LC, and LH, could be partly responsible for the changes in the temporal pattern of activity of DA neurons.

Sleep disruption, daytime somnolence and 'sleep attacks' in Parkinson's disease: a clinical survey in PD patients and age-matched healthy volunteers

Recent case reports of 'sleep attacks' (SA) in patients with Parkinson's disease (PD) generated concerns about drug-induced daytime somnolence in this population. However, there are nearly no comparative data on sleep and vigilance problems between PD patients and normal controls. We performed a cross-sectional survey in PD patients and age-matched controls using a structured questionnaire on PD history, treatments, co-morbidity, activities of daily living, habits, exercise, sleep pattern, driving, pre-existing nocturnal problems, daytime somnolence, episodes of SA and the circumstances in which such episodes occurred. Daytime somnolence was also measured with the Epworth Sleepiness Scale (ESS) and sleep quality with the Pittsburgh Sleep Quality Index (PSQI). 176 PD patients and 174 controls were included. The same proportion of PD patients (27%) and controls (32%) reported episodes of SA, but these were more frequent in PD patients and occurred more frequently during situations requiring attention (10.8% vs. 1.7%, p<10(-3)). More PD patients had abnormal daytime somnolence (ESS) and poor sleeping quality (PSQI). The most consistent factor associated with SA was the duration of levodopa therapy and the predictive value of an abnormal ESS score was rather poor (40.7%). Abnormal daytime somnolence and poor sleep quality at night are more frequent in PD patients than in normals. However, SA are reported in both groups, although less frequently in the normals during activities that requires attention.

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

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

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.

Treatment of Parkinson's disease : what's on the horizon?

Few neurological diseases have received as much attention and investment in research as Parkinson's disease. Although great strides have been made in the development of agents to treat this neurodegenerative disease, none yet address the underlying problem associated with it, the progressive loss of dopaminergic neurons. Current therapeutic strategies for Parkinson's disease focus primarily on reducing the severity of its symptoms using dopaminergic medications. Although providing substantial benefit, these agents are burdened by adverse effects and long-term complications. This review highlights new and emerging therapies for Parkinson's disease, categorised as symptomatic, neuroprotective and neurorestorative, although at times, this distinction is not easily made. Novel symptomatic treatments target nondopaminergic areas in the hope of avoiding the motor complications seen with dopaminergic therapies. Two emerging treatment approaches under investigation are adenosine A(2A) receptor antagonists (such as istradefylline [KW-6002]) and glutamate AMPA receptor antagonists (such as talampanel [LY-300164]). In 2003, the results from two studies using istradefylline in patients with Parkinson's disease were published, with both showing a positive benefit of the study drug when used as adjunctive therapy to levodopa. In non-human primate models of Parkinson's disease, talampanel has been found to have antiparkinsonian effects when administered as high-dose monotherapy and antidyskinetic effects on levodopa-induced dyskinesias. NS-2330, another drug currently undergoing clinical trials, is a triple monoamine reuptake inhibitor that has therapeutic potential in both Parkinson's and Alzheimer's disease. A phase II proof-of-concept study is currently underway in early Parkinson's disease. However, a recently published study in advanced Parkinson's disease showed no therapeutic benefit of NS-2330 in this patient population. Even more exciting are agents that have a neuroprotective or neurorestorative role. These therapies aim to prevent disease progression by targeting the mechanisms involved in the pathogenesis of Parkinson's disease. Several lines of investigation for neuroprotective therapies have been taken, including the antioxidant coenzyme Q10 (ubidecarenone) and anti-apoptotic agents such as CEP-1347. Studies in patients with Parkinson's disease with coenzyme Q10 have suggested that it slows down functional decline. The PRECEPT study is currently in progress to assess the neuroprotective role of CEP-1347 in the early phase of the disease. Gene therapy is another exciting arena and includes both potentially neuroprotective and neurorestorative agents. Novel methods include subthalamic glutamic acid decarboxylase gene therapy and the use of glial cell line-derived neurotrophic factor (GDNF). Eleven of 12 patients have been enrolled in the first FDA-approved phase I subthalamic glutamic acid decarboxylase gene therapy trial for Parkinson's disease, with currently no evidence of adverse events. GDNF delivered intracerebroventricularly was studied in a small population of patients with Parkinson's disease, but unfortunately did not reveal positive results. Other methods of administering GDNF include direct delivery via infusions into the basal ganglia and the use of viral vectors; thus far, these approaches have shown promising results. This is an exciting and rewarding time for research into Parkinson's disease. With so many therapies currently under investigation, the time is ripe for the beginning of a new phase of treatment strategies.

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.

Parkinson disease: an update

BACKGROUND

Over the past decade, the treatment of Parkinson disease (PD) has undergone tremendous changes. New drugs have been introduced to manage the cardinal motor symptoms of PD, and other agents have been borrowed to treat the nonmotor manifestations of the illness. For neurologists faced with the task of treating PD patients, the available array of medications may be confusing and intimidating.

REVIEW SUMMARY

In this review, I summarize the newest approved medications for the treatment of PD, including the new dopamine agonists and catechol-O-methyl-transferase inhibitors. I also describe agents that are used to treat common problems in PD patients, including hallucinations, orthostasis, nausea, erectile dysfunction, depression, and memory loss. Guidelines for handling common scenarios in PD patients will be illustrated by 10 case histories. Finally, the most promising PD drugs that are currently in development will be reviewed.

CONCLUSIONS

Neurologists have a vast armamentarium to treat both motor and nonmotor manifestations of PD. Understanding this array allows the astute clinician to improve the lives of their patients with PD.

Quantifying adverse drug events : are systematic reviews the answer?

Quantifying adverse drug events (ADEs) is critical to clinicians, consumers and policy makers. Most ADE information comes from large clinical trials. Systematic reviews have become a popular tool in quantifying the efficacy of different therapeutic interventions and ADE data collected in randomised trials may be helpful in quantifying the risk associated with a specific pharmacological agent. However, clinicians who are interested in conducting systematic reviews of ADEs may face many challenges. These challenges are geared towards two main areas: poor quality of ADE reporting in randomised trials and poor indexing of ADEs in medical databases. In this review, we will discuss these challenges in detail using some examples from the literature. Where possible, we also discuss strategies that may overcome these problems. More rigourous standards of reporting ADEs in randomised trials, as well as better indexing of ADE terminology in medical databases, could one day make systematic reviews of ADEs a powerful tool for practising clinicians.

Excessive daytime somnolence in Japanese patients with Parkinson's disease

To investigate the prevalence and severity of excessive daytime somnolence (EDS) in Japanese patients with Parkinson's disease (PD) and to examine the main cause of EDS. Fifty-three Japanese patients with PD (PDs: 32 females and 21 males) and 17 controls (10 females and seven males) were evaluated using the Epworth Sleepiness Scale (ESS). The severity of the disease was evaluated by Unified Parkinson's disease Rating Scale (UPDRS), and information about quality and quantity of medications was collected. The correlations amongst EDS and age, severity of PD, duration of illness and medications were analyzed. The mean ESS score was significantly higher in advanced PDs than in controls, and correlated with the UPDRS score (r(s) = 0.743, P < 0.0001). Age, duration of illness and the dose of levodopa weakly correlated with ESS score. The intake of dopamine agonists did not affect the severity of EDS. The mean ESS score in PDs was lower than that reported in PD in European and American studies. EDS in Japanese patients with PD was milder compared with Caucasian patients, which might be due to the lower doses of the medications used in Japan. The results suggest that EDS in PD is mainly because of neuropathological changes of the disease itself.

Apomorphine delays simple reaction time in Parkinsonian patients

BACKGROUND

Parkinsonian patients have difficulty in the preparation and execution of movements, which translate into delayed performance of simple reaction time (SRT) paradigms.

OBJECTIVE

To examine short-term effects of an acute subcutaneous injection of the dopamine agonist apomorphine on the results of a SRT task.

METHODS

We studied a SRT paradigm in 26 non-fluctuating idiopathic Parkinsonian patients, before and 30, 60, 90 min after administration of apomorphine.

RESULTS

The reaction time (RT) was significantly delayed after apomorphine injection. We found no significant change in movement time (MT).

CONCLUSION

Delay of RT and the lack of response of MT to apomorphine administration may result from the sedative effects of apomorphine, overstimulation of postsynaptic dopaminergic receptors with subsequent inhibition of prefrontal cholinergic neurotransmission, and at least partial binding of apomorphine to presynaptic dopaminergic autoreceptors, which cause inhibition of locomotor activity. We suggest that future studies testing the capacity for reaction in Parkinsonian patients should consider the exact timing of the delivery of dopamine substituting drugs prior to the test.

Differential response in choice reaction time following apomorphine based on prior dopaminergic treatment

Choice reaction time (CRT) paradigms demonstrated deficits in the preparation and execution of movements in patients with Parkinson's Disease (PD). Predominantly these trials did not consider an influence of acute and long-term dopaminergic substitution. Objective was to determine the acute effect of apomorphine on the response to a repeatedly performed CRT task. We repeatedly executed the CRT paradigm before and after subcutaneous apomorphine injection in previously treated, untreated and long-term dopamine substituted PD patients, who took placebo. No significant change of CRT and movement time (MT) appeared in PD patients with chronic dopaminergic drug intake after apomorphine injection. CRT and MT both significantly worsened in untreated PD patients. Placebo application induced no significant alteration. Binding of apomorphine to presynaptic autoreceptors with subsequent sedation or inhibition of locomotor activity hypothetically explain our results in before untreated PD patients. Previous long-term dopaminergic substitution may cause a certain tolerance to this phenomenon.

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 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.

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 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.

Sleep attacks in patients taking dopamine agonists: review

OBJECTIVES

To assess the evidence for the existence and prevalence of sleep attacks in patients taking dopamine agonists for Parkinson's disease, the type of drugs implicated, and strategies for prevention and treatment.

DESIGN

Review of publications between July 1999 and May 2001 in which sleep attacks or narcoleptic-like attacks were discussed in patients with Parkinson's disease.

RESULTS

124 patients with sleep events were found in 20 publications. Overall, 6.6% of patients taking dopamine agonists who attended movement disorder centres had sleep events. Men were over-represented. Sleep events occurred at both high and low doses of the drugs, with different durations of treatment (0-20 years), and with or without preceding signs of tiredness. Sleep attacks are a class effect, having been found in patients taking the following dopamine agonists: levodopa (monotherapy in 8 patients), ergot agonists (apomorphine in 2 patients, bromocriptine in 13, cabergoline in 1, lisuride or piribedil in 23, pergolide in 5,) and non-ergot agonists (pramipexole in 32, ropinirole in 38). Reports suggest two distinct types of events: those of sudden onset without warning and those of slow onset with prodrome drowsiness.

CONCLUSION

Insufficient data are available to provide effective guidelines for prevention and treatment of sleep events in patients taking dopamine agonists for Parkinson's disease. Prospective population based studies are needed to provide this information.

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.

Increased risk of somnolence with the new dopamine agonists in patients with Parkinson's disease: a meta-analysis of randomised controlled trials

BACKGROUND

Recent case reports and letters have alerted practitioners to the risk of sleep attacks, usually preceded by somnolence, in patients with Parkinson's disease treated with pramipexole and ropinirole.

OBJECTIVE

To quantify the risk of somnolence with the new dopamine agonists pramipexole and ropinirole in patients with Parkinson's disease.

METHODS

We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts and Cochrane Library, contacted experts and pharmaceutical manufacturers, and manually reviewed all references retrieved to identify possible articles to include. Information on randomisation, blinding, type of treatment and reporting of somnolence were abstracted by 2 independent reviewers. Disagreements were resolved by a third author.

ANALYSIS

We made 2 separate analyses. The first analysis compared the risk of somnolence in patients taking either pramipexole or ropinirole to that in patients taking placebo. The second analysis compared the risk of somnolence with these drugs (plus levodopa) versus that with levodopa alone. We calculated pooled relative risk estimates using the random effects model and when no heterogeneity was detected we used the fixed effects model.

RESULTS

Four trials were included in the analysis of patients taking pramipexole or ropinirole compared with those taking placebo. The pooled relative risk of somnolence in this analysis was 4.98 [95% confidence interval (CI) 1.79 to 13.89]. Seven trials were included in the analysis of patients taking levodopa and pramipexole or ropinirole compared with those taking levodopa alone. The pooled relative risk was 2.06 (95% CI 1.47 to 2.88).

CONCLUSION

Patients with Parkinson's disease using pramipexole or ropinirole are at higher risk of experiencing somnolence relative to patients taking placebo. Patients taking levodopa plus either one of these dopamine agonists are at higher risk than those taking levodopa alone. Clinicians should carefully weigh this risk against the benefit of these agents when prescribing these drugs.

Delay of simple reaction time after levodopa intake

BACKGROUND

Parkinsonian patients (PP) have deficits in the preparation and execution of movements. It is generally accepted that PP show delayed performance of simple reaction time (SRT) paradigms due to impaired response preprogramming. To date, no trial considered putative effects of dopaminergic substitution on SRT performance in PP.

OBJECTIVES

To determine short-term effects of acute levodopa intake and impact of long-term dopaminergic substitution on the results of a SRT task.

METHODS

We repeatedly performed a SRT paradigm in previously untreated- and treated PP, taken off medication for at least 12 h, before and after intake of levodopa/benserazide and in PP, who received placebo.

RESULTS

Reaction time significantly increased and movement time did not change after levodopa intake. Placebo application showed no effects.

CONCLUSIONS

Levodopa delayed cognitive processing and/or behaviour. Sedative effects of levodopa and/or dopamine overflow in prefrontal regions with subsequent cholinergic dysfunction hypothetically caused this phenomenon.

Irresistible onset of sleep during acute levodopa challenge in a patient with multiple system atrophy (MSA): placebo-controlled, polysomnographic case report

A 67-year-old male patient with clinically probable multiple system atrophy developed severe reproducible sleepiness and irresistible onset of sleep during an acute levodopa (L-dopa) challenge. In a placebo-controlled, double-blind study of acute L-dopa challenge, videopolysomnography revealed multiple episodes of non-rapid eye movement sleep 60 minutes after L-dopa and none following placebo. These observations suggest the irresistible sleep can also be induced by L-dopa and also in patients with atypical parkinsonism.

Sleep disorders in patients with Parkinson's disease: epidemiology and management

Patients with Parkinson's disease can experience a number of sleep disorders, including insomnia, parasomnias and daytime somnolence [specifically, excessive daytime sleepiness (EDS) and sleep attacks]. Insomnia is a frequent and important complaint of patients with the disease. Both the pathology of Parkinson's disease and dopaminergic drugs may contribute to the much higher than expected frequency of sleep fragmentation and disrupted sleep among these patients. In addition, coexisting depression seems to be a major and frequent risk factor for insomnia in Parkinson's disease. After recognising a sleep problem, the first step in management is to examine and diagnose the type of insomnia and possible medical or psychological factors that may disturb nocturnal sleep. The next step is to give the patient appropriate advice on sleep hygiene. Increasing the dosage of dopaminergic drug treatment will often increase sleep disruption and should be avoided unless the patient's sleep is primarily disturbed by the motor manifestations of parkinsonism during the night. Depression should be looked for and if appropriate be treated in any patients with insomnia. If it becomes necessary to treat the patient with an hypnosedative agent, it is important to use a drug with a short half-life and that manifests as few adverse effects as possible the next morning. Up-to-date guidelines for the use of hypnosedatives should be followed. Patients with Parkinson's disease experience a wide range of parasomnias. The majority of behaviours may be related to rapid eye movement (REM) sleep behaviour disorder (RBD) or to a spectrum of symptoms ranging from vivid dreaming to psychosis. RBD is effectively treated with clonazepam. In addition, the atypical antipsychotics have given physicians new and better treatment options for psychotic symptoms in individuals with Parkinson's disease. EDS is common in Parkinson's disease, while sleep attacks seem to be rare manifestations of the disease or its treatment. Significant EDS is found in 15% of patients with Parkinson's disease compared with in 1% of healthy elderly people. Sleep attacks are observed in patients treated with all dopaminergic medications but have recently been brought to prominence because of their association with the newer dopamine agonists ropinirole and pramipexole. Patients with Parkinson's disease should be informed about the possibility of developing sleep problems during the day when prescribed new drugs. Appropriate actions with regard to driving must be taken if significant and persistent daytime somnolence or sleep attacks appear.

Sleep attacks and antiparkinsonian drugs: a pilot prospective pharmacoepidemiologic study

A prospective survey was performed to characterize the prevalence of sleep attacks and to evaluate precipitating factors in a group of 236 patients with idiopathic Parkinson's disease. Sleep attacks were reported by 72 patients (30.5%). Multivariate analysis showed a marked association between the occurrence of sudden sleep episodes and first autonomic failure, followed by treatment with ropinirole and bromocriptine. The present work underlines the major contributing role of autonomic failure followed by dopamine agonists in the occurrence of such an event. Because a relationship between sleep attacks and not only ropinirole but also bromocriptine treatment was described, the present work suggests that sleep attacks are a common side effect of all dopamine agonists.

Sleep disorders in Parkinson's disease: the nursing role

The quality of life of people with Parkinson's disease (PD) and their carers is often made worse by impaired sleep. Sleep problems are common in PD and there are several causative factors in their aetiology including the ageing process, anti-Parkinson's disease medication, the disease process itself, and concomitant factors such as nocturia, anxiety and immobility. Non-pharmacological approaches are the most desirable method to treat sleep-related problems. The nurse can have an important role in assessing sleep, providing support, offering practical advice, and making appropriate referrals. This article will discuss the various sleep problems experienced in PD, the underlying aetiology, and the role of the nurse.