Decreased phasic EMG activity during rapid eye movement sleep in treatment‐naïve Parkinson's disease: Effects of treatment with levodopa and progression of illness

Abstract

Rapid eye movement (REM) sleep behavior disorder (RBD) is frequently associated with Parkinson's disease (PD) and may anticipate its diagnosis by several years. We assessed the presence of motor dyscontrol during REM sleep in treatment-naïve PD patients and investigated the putative effect of levodopa (L-dopa) treatment on motor activity. Overnight sleep studies were performed on 15 previously untreated PD patients and 14 controls at baseline, again after a 3- to 9-month treatment period with a low dose of L-dopa, and 2 to 5 days after treatment discontinuation (in 8 patients). No differences in sleep parameters were observed across groups or treatment conditions. None of the patients met criteria for RBD at baseline, whereas 5 patients were symptomatic at the time of the second sleep study. A quantitative analysis of electromyographic (EMG) activity during REM sleep showed a lower phasic twitching activity in untreated PD than in controls. However, an increase in both phasic twitching and tonic activity was found after treatment with L-dopa. Discontinuation of treatment resulted in a return to pretreatment values of phasic but not of tonic EMG activity. Thus, the increase in phasic activity seems to depend on the effects of L-dopa, whereas the increase in tonic EMG activity during REM sleep might be caused by other factors such as the progression of disease. Potential implications for the understanding of the relationship between RBD and PD are discussed.

Sleep disturbances in untreated Parkinson’s disease

“…Therefore, in an apparent discordance with the notion that RBD would regularly precede parkinsonism as an early manifestation of PD reflecting lower brainstem involvement [8], our results and the other studies [21,27,39] suggest that prominent REM sleep dysregulation is not, in an important proportion of patients, associated with the early stage of the disease. However, a rather high occurrence of RWA and its correlation with motor scores in the present study underscore the assumption that RWA is probably on the same disease spectrum as RBD, reflecting neurodegeneration in early PD [8].…”

“…Nevertheless, we have detected only one patient with clinically manifested RBD between our de novo patients. Similarly, in previous polysomnographic studies in de novo PD, some of the patients presented signs of RWA but only rarely revealed clinical RBD [21,27,39]. In line with these findings, even in a more advanced disease, a questionnaire survey detected signs of RBD in only 33% of 195 PD patients and in 73% of these, the signs of parkinsonism preceded RBD [34].…”

“…The most worrying aspect of daytime sleepiness in PD is the ''sleep attack'', sudden, irresistible, overwhelming sleepiness without awareness of falling asleep [24]. However, most of the studies on sleep disturbances in PD involved patients who had already been treated with dopaminergic drugs, whereas there are only few questionnaire surveys [16,17] and polysomnography studies in non-medicated PD patients [18,21,27,38,39].…”

Sleep disorders and daytime sleepiness in Parkinson’s disease

“…In PD, one study found that 74% of patients taking levodopa had disruption of nighttime sleep. Levodopa has been shown to increase REM sleep latency and to reduce REM sleep duration in some studies but not others [23]. At low doses, dopamine agonists promote sleep due to the stimulation of inhibitory D2 receptors in the ventrolateral tegmental area.…”

Excessive Daytime Somnolence Associated with Parkinson’s Disease

“…Levodopa and dopamine agonists can adversely affect nighttime sleep resulting in EDS. A study of PD patients taking levodopa found that 74 % had a disruption of nighttime sleep [ 22 ].…”