Objective: This study aimed to evaluate whether rapid eye movement )REM( sleep without atonia )RWA( is similar throughout multiple REM cycles during one night.
Background: REM sleep behavior disorder (RBD) is a prodromal marker of Parkinson’s disease (PD). Definite diagnosis of RBD requires detection of RWA on a polysomnographic recording (PSG). Little is known about the distribution of RWA across the night.
Method: Sixty-eight participants underwent a night in a sleep laboratory (PSG). Muscle atonia was determined based on EMG signals collected from the mentalis muscle and flexor digitorum superficialis and tibialis anterior bilaterally. Thirty-eight participants were excluded from this analysis due to high respiratory index (AHI>15), extensive periodic limb movement (PLMS>30), taking SSRI, or having less than 2 REM cycles. The percentage of time in RWA (%RWA) was determined based on a 30-sec epoch using the American Association for Sleep Medicine (AASM) criteria and compared between the different REM cycles using the non-parametric Wilcoxon test.
Results: RWA was detected in 26 participants ranging from 1.3% to 40.2% (mean age 57.5±9.5 years, 11 PD patients, 9 females). On average, participants spent 56.4±24.6 minutes in REM sleep, spread across 2-5 REM cycles. RWA was detected in 84 out of 87 REM cycles (97%). The %RWA of the 1st REM cycle (median 3.2%) was significantly lower than the total %RWA averaged across all cycles (median 6.7%, p<0.01). There was no difference in the average %RWA in the 1st and 2nd REM cycles (median 7.3%) compared to the total %RWA in all cycles.
Conclusion: Participants presenting with only one REM cycle on PSG could present underestimated %RWA, while two REM cycles are representative of total estimate of all REM cycles during the night. This finding has clinical implications for diagnosing RBD in people presenting with less than two REM cycles in a PSG lab.
To cite this abstract in AMA style:
A. Dagay, S. Oz, SH. Katzav, D. Wasserman, N. Giladi, A. Mirelman. Distribution of rapid eye movement (REM) sleep without atonia (RWA) across the REM cycles. [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/distribution-of-rapid-eye-movement-rem-sleep-without-atonia-rwa-across-the-rem-cycles/. Accessed June 15, 2025.« Back to 2022 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/distribution-of-rapid-eye-movement-rem-sleep-without-atonia-rwa-across-the-rem-cycles/