Excessive daytime sleepiness (EDS) is a frequent complaint of PD patients. The description of ''sleep attacks'' and motor vehicle accidents in PD patients taking either pramipexole or ropinirole published in 1999 stimulated interest in this topic (Frucht et al., 1999). In one community based study (Tandberg et al., 1999), EDS was seen in 15.5% of PD patients compared to 4% of patients with diabetes mellitus and 1% of controls. EDS was associated with more severe PD, greater PD-related disability, cognitive decline, more frequent hallucinations and a longer duration of levodopa therapy. Longitudinal assessments of EDS in PD over a 4 year span show that 8% had EDS at baseline. In these patients EDS persisted and an additional 21% developed new symptoms of EDS. The factors associated with development of EDS in this study included dementia, and more rapid progression of parkinsonism (Gjerstad et al., 2002). Additional studies have confirmed the frequent occurrence of EDS in PD and examined the role of dopaminergic therapy in its genesis (Arnulf et al., 2002; Hobson et al., 2002; Roth et al., 2003; Braga-Neto et al., 2004; Pal et al., 2004; Razmy et al., 2004). Levodopa has been known to cause sleepiness since its introduction in the 1960's. In one early series of 131 PD patients (Lesser et al., 1979), levo-dopa monotherapy caused somnolence that limited levodopa dosage in 14% of patients. Comparisons between dopamine agonists and levodopa have shown that both classes of drug cause somnolence (Hauser et al., 2000). Others have found a variety of factors associated with EDS in PD, including severity of PD and total dose of all dopaminergic agents (Hobson et al., 2002; Razmy et al., 2004; Stevens et al., 2004) and confirm that any antiparkinson medication can cause daytime sleepiness in PD patients.
Several studies using polysomnography and MSLT suggest that daytime sleepiness may be a primary feature of PD, unrelated to PD treatments, or nocturnal sleep disturbance (Rye et al., 2000; Arnulf et al., 2002; Roth et al., 2003). A current hypothesis is that sleepiness or a susceptibility to EDS may be an integral part of PD, reflecting the extent of the neurodegenerative process.
The diagnosis of excessive daytime sleepiness is begins with patient and caregiver interview. The interview should include sleep habits, presence of nocturnal sleep disruption (snoring, respiratory pauses, movements in sleep), and a complete drug history. The ESS provides a useful tool that is practical in an office setting for evaluating the presence and severity of EDS. When combined with the Inappropriate Sleep Composite index, it serves to identify those PD patients at risk for falling asleep at the wheel. Although anecdotal reports of PD patients involved in driving mishaps have appeared (Frucht et al., 1999, 2000; Hauser et al.,
2000), in the absence of a systematic investigation, whether PD patients who drive are at greater risk for motor vehicle accidents whether or not on dopamine agonists, remains to answered (Homann et al., 2003).
Treatment of daytime sleepiness in PD includes assessment of the patient for possible nocturnal sleep disturbance. Sleep apnea, periodic limb movements and other disorders that disrupt nocturnal sleep should be considered. This often involves referral to a sleep specialist. Drugs that can cause sleepiness should also be assessed. If a patient reports onset of EDS following initiation or increased dosage of dopaminergic therapy, either a reduction in dose or a switch to another drug may be necessary. Likewise, discontinuation or change in drugs prescribed for another medical condition or diagnosis and treatment of conditions such as depression may be beneficial for treatment of EDS. The administration of daytime stimulant medications is reserved for those patients who are unresponsive to other medication adjustments. The amphetamine metabolites of selegiline may increase alertness. Modafinil, a stimulant drug approved for treatment of EDS in narcolepsy, may also be of modest benefit as has been shown in two controlled studies in a small number of PD patients with excessive daytime sleepiness (Hogl et al., 2002; Adler et al., 2003).
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Who Else Wants To Sleep From Lights Out 'Til Sunrise Without Staring At The Ceiling For Hours Leaving You Feeling Fresh And Ready To Face A New Day You know you should be asleep. You've dedicated the last three hours in the dark to trying to get some sleep. But you're wide awake.