Daytime sleepiness in Parkinson's disease: a reappraisal.

BACKGROUND: Excessive daytime sleepiness is a frequent complaint in Parkinson's disease (PD); however the frequency and risk factors for objective sleepiness remain mostly unknown. We investigated both the frequency and determinants of self-reported and objective daytime sleepiness in patients with Parkinson's disease (PD) using a wide range of potential predictors. METHODS: One hundred and thirty four consecutive patients with PD, without selection bias for sleep complaint, underwent a semi-structured clinical interview and a one night polysomnography followed by a multiple sleep latency test (MSLT). Demographic characteristics, medical history, PD course and severity, daytime sleepiness, depressive and insomnia symptoms, treatment intake, pain, restless legs syndrome, REM sleep behaviour disorder, and nighttime sleep measures were collected. Self-reported daytime sleepiness was defined by an Epworth Sleepiness Scale (ESS) score above 10. A mean sleep latency on MSLT below 8 minutes defined objective daytime sleepiness. RESULTS: Of 134 patients with PD, 46.3% had subjective and only 13.4% had objective sleepiness with a weak negative correlation between ESS and MSLT latency. A high body mass index (BMI) was associated with both ESS and MSLT, a pain complaint with ESS, and a higher apnea/hypopnea index with MSLT. However, no associations were found between both objective and subjective sleepiness, and measures of motor disability, disease onset, medication (type and dose), depression, insomnia, restless legs syndrome, REM sleep behaviour disorder and nighttime sleep evaluation. CONCLUSION: We found a high frequency of self-reported EDS in PD, a finding which is however not confirmed by the gold standard neurophysiological evaluation. Current treatment options for EDS in PD are very limited; it thus remains to be determined whether decreasing pain and BMI in association with the treatment of sleep apnea syndrome would decrease significantly daytime sleepiness in PD.

Decision-making, reward-seeking behaviors and dopamine agonist therapy in restless legs syndrome.

STUDY OBJECTIVES: To assess whether the frequency of impulse control disorders (ICDs), addictive behaviors, impulsivity, and impairment of decision-making task performance under ambiguous and risky conditions were present in patients with restless legs syndrome (RLS) and whether changes could be related to dopaminergic medications. DESIGN: Case-control prospective study. SETTING: Academic Sleep Disorders Center. PARTICIPANTS: Of the 149 participants, there were 39 who were drug free with primary RLS, 50 who were taking dopamine agonists (DA), and 60 control subjects. Participants were assessed with a clinical interview screening for ICDs, augmentation syndrome, impulsivity, depression, and addictive behaviors. All participants completed two decision-making tasks, one under an ambiguous condition (Iowa Gambling Task) and the other under a risky condition (Game of Dice Task). Drug-free patients with RLS underwent 1 night of polysomnography recording. MEASUREMENTS AND RESULTS: Seventy percent of patients were treated with pramipexole (median dose, 0.36 mg), and 30% with ropinirole (median dose, 0.75 mg). Median duration of DA intake was 11 mo (range, 1-72 mo). No differences were found on impulsivity scores, ICDs, and substance addiction between drug-free patients or those taking DA, or control subjects. Patients with RLS reported more depressive symptoms than control subjects, but without differences between patients taking or not taking DA. Drug-free and treated patients demonstrated reduced performances on the Iowa Gambling Task but not on the Game of Dice Task compared to control subjects, with no differences between patients taking medications and those who were not. No association was found between decision-making task performances, or polysomnographic and clinical variables. CONCLUSION: Impulse control disorders, impulsivity, and substance addiction were infrequent in drug-free patients with restless legs syndrome or those treated with a low dose of dopamine agonists. However, patients with restless legs syndrome, either drug free or taking dopamine agonists, had preferences toward risky choices on the Iowa Gambling Task, which led to negative consequences in the long run, a condition potentially leading to further development of impulse control disorders.

Effect of psychostimulants on impulsivity and risk taking in narcolepsy with cataplexy.

OBJECTIVE: To investigate the effect of psychostimulants on impulsivity, depressive symptoms, addiction, pathological gambling, and risk-taking using objective sensitivity tests in narcolepsy with cataplexy (NC). Drug-free patients with NC present alterations in reward processing, but changes with psychostimulants remain unknown. DESIGN: Prospective case-control study. SETTING: Academic sleep disorders center. PARTICIPANTS: There were 120 participants: 41 drug-free patients with NC, 37 patients with NC taking psychostimulants, and 42 matched healthy controls. INTERVENTIONS: All participants underwent a semistructured clinical interview for impulse control and addictive behaviors and completed questionnaires for depression and impulsivity. Risk taking was analyzed through performance on a decision-making task under ambiguity (Iowa Gambling Task [IGT]) and under risk (Game of Dice Task [GDT]). All patients with NC underwent 1 night of polysomnography followed by a multiple sleep latency test for drug-free patients and a maintenance wakefulness test for treated patients. RESULTS: Depressive symptoms were higher in drug-free patients than in treated patients and controls, with no difference between controls and treated patients. No between-group differences were found for impulsivity, substance addiction, or pathological gambling. Drug-free and treated patients showed selective reduced performance on the IGT and normal performance on the GDT compared with controls, with no differences between patients taking medication and those who did not. No clinical or polysomnographic characteristics or medication type was associated with IGT scores. CONCLUSIONS: Our results demonstrated that, whether taking psychostimulants or not, patients with narcolepsy with cataplexy preferred risky choices on a decision-making task under ambiguity. However, the lack of association with impulsivity, pathological gambling, or substance addiction remains of major clinical interest in narcolepsy with cataplexy.

Decision making in restless legs syndrome.

The dopamine system is implicated in reward-based decision making with explicit information (decision making under risk) and implicit probabilities (decision making under ambiguity). Although the pathophysiology of restless legs syndrome (RLS) is not yet fully understood, the genetic factors, iron status, and dopaminergic system are thought to play a role. RLS provides an opportunity to test the dopaminergic hypothesis in a drug-free population and to characterize reward processing using decision-making paradigms. We investigated impulsivity, impulse control disorders, and decision making in 50 untreated patients with primary RLS compared with 60 sex- and age-matched normal controls using one night of polysomnography recording, a structured psychiatric interview, and questionnaires (RLS Severity Scale, Beck Depression Inventory, and Urgency Premeditation Perseverance Impulsive Behavior Scale). Subjects performed the Iowa Gambling Task to assess decision making under ambiguity and the Game of Dice Task to assess decision making under risk. Patients with RLS showed selective changes in decision making on the Iowa Gambling Task and normal decision making on the Game of Dice Task compared with controls. Patients with RLS had greater depressive symptoms than controls, but no difference was found in impulsivity, impulse control disorders, or addictive behaviors. Clinical and polysomnographic variables were unrelated to decision-making performance. Results indicate reduced decision-making performance under ambiguity in drug-free patients with RLS. From a clinical perspective, when using dopaminergic medication to treat RLS, patients with abnormal baseline behaviors should be closely monitored.