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PATIENTS AWARE OF DAYTIME SLEEP ATTACKS?
SEATTLE—More than one third of patients with Parkinson’s disease are unaware of having daytime sleep episodes, with each episode lasting for a mean of 12 minutes, according to Isabelle Arnulf, MD. This impaired sleep perception may result from cognitive defects, and not from pharmacotherapy, she reported. Her team’s study suggests that “daytime sleepiness, associated with a poor recollection of daytime sleep, is a characteristic of a subset of Parkinson’s disease patients and that this is not associated with dopamine-agonist treatment,” said Dr. Arnulf.
Dr. Arnulf is affiliated with the Fédération des Pathologies du Sommeil at the Hôpital Pitié-Salpêtrière in Paris. She presented her findings at the 16th Annual Meeting of the Association of Professional Sleep Societies.
Excessive daytime sleepiness has been reported in as many as 15% of patients with Parkinson’s disease, Dr. Arnulf related. Previous research has suggested that motor vehicle accidents among patients with Parkinson’s disease may be due to the sudden onset of sleep, and other studies have concluded that dopamine agonists are associated with these sleep attacks. However, there is increasing evidence that patients with Parkinson’s disease have an inherently poor perception of sleep-wakefulness transition. “We noted that there was a poor correlation between an objective measure of sleepiness and subjective measure of sleepiness,” said Dr. Arnulf. Therefore, she and her colleagues sought to determine if Parkinson’s disease patients were aware that they fell asleep during the day.
Dr. Arnulf and colleagues examined 56 patients (45 men) with moderate Parkinson’s disease, who ranged in age from 53 to 85 years. The participants underwent polysomnography and multiple sleep latency tests. Subjects’ Mini-Mental State Examination scores ranged from 16 to 30, and their mean Epworth score was 14. All patients were treated with levodopa, and 26 of them were treated with dopaminergic agonists as well. After each nap, the subjects were asked if they thought they had slept. “If the answer was ‘yes,’ or something like ‘I’m not sure, I may have slept,’ they were considered a conscious patient. And if the answer was ‘no,’ they were considered an unconscious patient,” said Dr. Arnulf.
A total of 277 tests were performed, with 241 sleep episodes recorded. Twenty-one patients (who experienced a total of 34 sleep episodes) did not perceive that they had fallen asleep or napped. Sleep episodes that were not perceived were similar in duration to those that the patients were aware of. In addition, both perceived and nonperceived sleep episodes had similar proportions of slow wave (mean of 21% versus 34%, respectively) and REM sleep (mean of 26% versus 28%, respectively), said Dr. Arnulf. The patients who had an impaired perception of sleep were of the same age as those who perceived sleep. In addition, both groups were predominately male, they experienced the same length and severity of their disease, and they had the same level of cognitive impairment. Levodopa dose and presence and dose of dopaminergic agonists were also comparable, she reported.
“There were 20% of the naps containing stage 2 that were not perceived,” said Dr. Arnulf. “There’s just 9% containing stages 3 and 4 and 13% containing REM sleep that were not perceived.” These percentages were not statistically different. Although the daytime sleep latency was similar among all groups, “Patients who did not perceive sleep episodes tend to underscore themselves on the Epworth Sleepiness Scale, with a mean number of 12 versus a mean number of 15 in those who perceived well their daytime sleep,” Dr. Arnulf noted. This lack of awareness among “unconscious” patients, she emphasized, “could potentially make them dangerous at the wheel.”
To illustrate this point, Dr. Arnulf provided data from her own study group. There were four vehicle mishaps involving study participants—three car accidents and one instance of a patient driving in the wrong direction on a highway. “They were all in the misperception group, so it must mean something,” she concluded.
One area of research that requires further study is cognitive deficits measurement, noted Dr. Arnulf. “The only cognitive test that was performed was the Mini-Mental test, which is not very sensitive,” she said. “More studies are needed to explore possible differences in cognition between subjects who were able to perceive sleep and those who were not.”
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—Colby Stong
Suggested Reading
Arnulf I, Konofal E, Merino-Andreu M, et al. Parkinson’s disease and sleepiness: an integral part of PD. Neurology. 2002;58:1019-1024.
Frucht S, Rogers JD, Greene PE, et al. Falling asleep at the wheel: motor vehicle mishaps in persons taking pramipexole and ropinirole. Neurology. 1999;52:1908-1910.
Homann CN, Forstner M, Ivanic G, Ott E. Daytime sleepiness and other sleep disorders in Parkinson’s disease. Neurology. 2002;58:1863-1864.
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Dopaminergic
Drugs
and Daytime Sleepiness—
Is the Jury Still Out?
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The conclusion is not unanimous regarding the effects
of drug treatment on daytime sleepiness in patients
with Parkinson’ disease. A study in the June
Archives of Neurology found that somnolence
in patients with Parkinson’s disease, which is
about 25% higher than in patients with other
neurologic diseases, is related to disease stage,
levodopa dose, and the use of a dopamine agonist.
The report added, however, that most of the variability
in sedation in patients with Parkinson’s disease
and in controls resulted from unidentified factors.
By evaluating 368 patients with Parkinson’s
disease and 243 controls, Padraig E. O’Suilleabhain,
MB, and Richard B. Dewey, Jr, MD, sought to separate
and quantify the contributions of disease markers
and drug doses. The results showed that Epworth Sleepiness
Scale scores were higher in patients who used levodopa
therapy than in those not taking levodopa, and they
were also higher in subjects using dopamine agonists
compared with those not using them. Epworth scores
were not higher in patients with Parkinson’s
disease who have dementia, depression, or hallucinations
compared with subjects without these comorbidities.
No statistically significant dose response was found
for agonists. In addition, there was no statistically
significant difference in sedation among the commonly
used dopamine agonists.
“We now ask all our patients about daytime somnolence.
In the few patients with a clear temporal relationship
between drug dosing and sedation, we reduce or change
the offending drug,” reported the investigators.
“Because levodopa therapy contributes modestly
to the problem for the average patient with Parkinson’s
disease, we pay more attention to other drugs that
may have sedative adverse effects, and to nocturnal
sleep patterns.”
—Colby Stong
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Suggested Reading
O’Suilleabhain PE, Dewey RB Jr. Contributions
of dopaminergic drugs and disease severity to daytime
sleepiness in Parkinson disease. Arch Neurol.
2002;59:986-989.
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