Effect of L-dopa on the sleep of man

The centennial lesson of encephalitis lethargica

We commemorate the centenary of Constantin von Economo's description of encephalitis lethargica, a mysterious disease that had a significant effect on 20th-century neuroscience. In the acute phase, encephalitis lethargica was marked by intractable somnolence, which von Economo attributed to lesions in the diencephalon, thereby paving the way for future efforts to localize the regulation of sleep in the subcortical brain. At the same time, neuropathologic findings in postencephalitic parkinsonism affirmed the role of the substantia nigra in the pathophysiology of parkinsonism. The occurrence of psychiatric symptoms in patients with encephalitis lethargica-such as mood disorders, obsessive-compulsive behavior, and bradyphrenia-drew attention to the organic basis of mental illness.

Association between dopaminergic medications and nocturnal sleep in early-stage Parkinson's disease

BACKGROUND

Poor nocturnal sleep is common in Parkinson's disease (PD) and negatively impacts quality of life. There is little data on how dopaminergic drugs influence nocturnal sleep in PD, particularly in relation to medication timing. We examined the association between dopaminergic medications and subjective and objective nocturnal sleep in PD.

METHODS

Individuals with PD were recruited from the outpatient clinic. Demographics and disease information were collected. Patients underwent one-night polysomnography and responded to SCOPA-SLEEP, a self-administered questionnaire which includes a section on nighttime sleep and an overall measure of sleep quality; higher scores indicate worse sleep. Medication intake, including medication timing in relation to bedtime, was obtained and converted to levodopa equivalents.

RESULTS

41 Males and 21 females, median age 63.9 years, participated. Median disease duration was 5 years. After adjusting for age, sex, disease severity, and disease duration, greater total levodopa equivalent intake within 4 h of sleep was associated with higher total SCOPA-nighttime score (p = 0.009) and greater wake time after sleep onset (p = 0.049). Greater dopaminergic medication intake prior to sleep was also associated with less rapid eye movement (REM) sleep as a percent of total sleep time (p = 0.004).

CONCLUSIONS

Higher amounts of dopaminergic medications taken prior to sleep were associated with poor sleep quality and less REM sleep. Although poor nocturnal sleep in PD is likely multi-factorial in etiology, our findings suggest that timing and dose of medications prior to sleep need to be considered in its management.

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.

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

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

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.

Rivastigmine in the treatment of parkinsonian psychosis and cognitive impairment: preliminary findings from an open trial

This open study assessed the ability of rivastigmine to treat the neuropsychiatric complications of advanced Parkinson's disease. In a group of 12 patients, hallucinations, sleep disturbance, and carer distress were all improved and cognitive performance significantly enhanced by the drug.

Sleep disorders and depression in patients with Parkinson's disease

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Drug-induced sleep disturbances. Focus on nonpsychotropic medications

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

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

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

Drug effects on REM sleep and on endogenous depression

In earlier work REM sleep deprivation (RSD) by arousals improved endogenous depression. This suggested that drugs producing a similar RSD would have antidepressant activity. The arousal RSD was large, persisted for weeks, and was followed by a REM rebound. We call RSD with these properties arousal-type RSD. The present study reviewed literature from 1962 to 1989 on drug REM sleep effects to examine the hypothesis that drugs producing arousal-type RSD improve endogenous depression. The literature reviewed concerned the REM sleep effects of amine precursors, antidepressants, antihistamines, antipsychotics, barbiturates, benzodiazepines, other hypnotics, drugs affecting cholinergic and noradrenergic neurotransmission, ethanol, lithium and narcotics. Four hundred and sixty-eight relevant papers were read and 215 contributed information that could be used in the review. The findings indicated that all drugs producing arousal-type RSD improved endogenous depression. Four drugs that improved endogenous depression did not produce arousal-type RSD.

Suppression of REM and delta sleep by apomorphine in man: a dopamine mimetic effect

Apomorphine, a direct stimulant of dopamine receptors, was given in nonemetic doses by continuous IV infusion for 180-240 min during night sleep in normal subjects. During apomorphine infusion, a significant reduction of stage (S)4 and an abolition of rapid eye movement (REM) sleep occurred. The percent duration of S2 was significantly increased. In the 240 min following interruption of 240-min infusion of apomorphine, a significant increase of S4 and REM percent duration was observed. The effect of apomorphine infusion on sleep was prevented by the administration of haloperidol or sulpiride, two dopamine receptor blocking agents. This suggests that it is due to a dopamine mimetic action.

EEG sleep patterns in Parkinsonian patients treated with bromocryptine and L-dopa: a comparative study

The nocturnal sleep patterns of six Parkinsonian patients treated with Bromocryptine (2-Br-L-ergocryptine CB-154), a dopamine-like agonist, were compared with those of the same patients under L-DOPA treatment. No significant differences were found between the two groups. It is suggested that Bromocryptine, acting on dopamine receptors in the sleep regulating systems at the reticular level in the midbrain has the same effect on sleep patterns of Parkinsonian patients as L-DOPA.

Hypersomnia with simultaneous waking and sleep patterns in the electroencephalogram. A case report with neurotransmitter studies

A mildly dyslexic boy of 11 years, with no neurological deficit or history of epileptic seizures, had marked hypersomnia for 2 years, which was most pronounced in the morning hours. Repeated EEG studies and power spectral analysis revealed simultaneous posterior alpha rhythm and sleep patterns (spindles, vertex waves, K complexes) over vertex and frontocentral regions, while the patient was behaviorally awake. Bilateral synchronous anterior spikes were frequently noted in association with sleep patterns. A polysomnogram over 24 h confirmed excessive sleep, night and day (especially morning hours) and there was evidence of a large REM sleep percentage (on EMG and EOG basis) while the EEG had predominantly non-REM sleep patterns. Special neurotransmitter studies were performed in view of a presumed disturbance affecting the neurobiochemical sleep regulation. These studies were based on CSF metabolite levels and provided evidence for a high serotonin metabolite (5HIAA) level. It is tempting to hypothesize that the biochemical disturbance has led to encroachment of non-REM sleep patterns on both wakefulness and REM sleep. Further discussion deals with the bilateral-synchronous spike activity and its relationship to arousal patterns in sleep.

Application of Mie theory and cubic splines to the representation of light scattering patterns from bacteria in the logarithmic growth phase

The angular dependence of light scattered by spherical bacteria cannot be explained accurately by treating them as homogeneous spheres with a simple size distribution determined by electron microscopy. Calculations indicated that structural features of the bacterial cell, such as its wall, were responsible, at least in part, for the poor agreement. Thus, there is no simple theoretical model available for light scattering by bacteria. Empirical methods have, therefore, to be used to describe the curves, e.g. for antibiotic sensitivity tests. Cubic splines provide a suitable empirical method.

Dream phenomena induced by chronic levodopa therapy

Twenty-seven of eighty-eight (30.7%) Parkinsonian patients on chronic levodopa or levodopa/carbidopa therapy developed drug related dream phenomena. The patients reported three separate types of new dreams which we have classified as vivid dreams, night terrors and nightmares. These dreams are correlated to the duration of levodopa therapy although the mechanism of their production is unclear.

Myoclonic attacks induced by L-dopa and bromocryptin in Parkinson patients: a sleep EEG study

Six patients with Parkinson's disease developed nocturnal myoclonic attacks after prolongued treatment with L-Dopa which were electroencephalographically recorded. These symptoms persisted after treatment with 2 bromo-alpha-ergocryptin (Bromocryptin), a dopamine receptor agonist, which was substituted for L-Dopa. Bromocryptin is known to have no pre- or postsynaptic effect on serotonin metabolism. It is proposed that these myoclonic phenomena are the expression of the hypersensitivity of denervated catecholamine receptors in the brainstem to the stimulation of L-Dopa and Bromocryptin. This thesis differs with previous suggestions that serotonin plays a major role in the genesis of myoclonic seizures in Parkinsonian patients treated with L-Dopa.

Epilepsy and schizophrenia: a neurochemical bridge

This paper reviews some of the evidence in the literature that suggests neurochemical processes by which the regulation of seizure threshold and the onset of schizophrenic-like symptoms are interrelated. For those patients who experience the alternation of seizures and acute psychoses the following working hypothesis is presented: The central dopaminergic synapse is described as a malfunctioning regulatory circuit. Insufficient feedback inhibition or lifting of the setpoint leads to an increased number of occupied receptors. This might cause schizophrenic-like symptoms. Insufficient release of feedback control or lowering of the setpoint leads to a decreased number of occupied receptors. This might increase seizure susceptibility. The neurochemical arguments in support of this hypothesis will be discussed in detail. The localization of the dopaminergic synapses involved in the development of schizophrenic-like symptoms is subject to speculation. The meso-limbic dopaminergic system has to be taken into consideration.

Effects of central dopaminergic blockade with primozide upon the EEG stages of sleep in man

The effect of pimozide, a potent and specific blocker of central dopaminergic transmission, upon the sleep of man was studied in six healthy volunteers. Given at doses of 1 and 4 mg, which have clear central effects in humand. pimozide produced only minor changes in the EEG patterns of sleep. At these doses a slight and non-significant decrease in phase I sleep was observed, while phases W,II,III,IV and REM were not modified. No differences were noted between drug or post-treatment and control nights in total NREM sleep, total REM sleep, number of episodes of REM or total number of eye movements. An increase in REM sleep in the first REM period in the first drug night were the only statistically significant findings. If one accepts that central effects seen in man after pimozide given in conditions similar to those of this study are due to dopaminergic blockade, our results tend to suggest that dopamine is, at most, of rather minor importance in the physiology of sleep in man.

Psychiatric aspects of L-dopa therapy of Parkinson's disease

Psychiatric complications of L-dopa treatment of Parkinson's disease at our hospital were less frequent and severe than reported at other institutions. Psychosocial factors were much more prominent in the complications that did occur than a pharmacologic effect of L-dopa. Interest in the connections between L-dopa, catecholamine metabolism and emotional disorder should not lead to neglect of medical-psychological aspects of L-dopa therapy.