Abstract Details

Title Quantitative Differences in REM Sleep Without Atonia Among Narcolepsy Type One, Narcolepsy Type Two, and Idiopathic Hypersomnia

Topic Sleep

Presentation(s) P3 - Poster Session 3 (5:00 PM-6:00 PM)

Poster/Presentation
Number 14-010

Objective To compare quantitative REM sleep without atonia (RSWA) across narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), and idiopathic hypersomnia (IH) and evaluate diagnostic discrimination.

Background RSWA is the electromyographic hallmark of REM sleep behavior disorder and occurs in over half of patients with narcolepsy, where it is postulated to reflect hypocretin deficiency. The degree of RSWA among NT1, NT2, and IH has not been systematically compared in adults.

Design/Methods We retrospectively analyzed 77 adults (20 NT1, 25 NT2, 32 IH) without antidepressant use who underwent polysomnography (PSG) followed by multiple sleep latency testing (MSLT) at our sleep center from 2022-2024. RSWA was quantified on mentalis and flexor digitorum superficialis EMG as percent REM epochs with excessive muscle tone based on the definition in AASM scoring manual version 3.

Results Median RSWA was 2.5%[0.12%, 3.7%] in NT1, 0%[0%,3%] in NT2, and 0%[0%,1.6%] in IH (p = 0.028). In age- and sex- adjusted regression, RSWA was significantly greater in NT1 compared with NT2 (rate ratio = 0.36, 95 % CI 0.14–0.95, p = 0.039) and IH (rate ratio = 0.13, 95 % CI 0.05–0.35, p < 0.001). IH also showed lower RSWA than NT2 (rate ratio = 0.37, 95 % CI 0.14–0.93, p = 0.035). Higher RSWA was correlated with higher percentage of PSG REM sleep (p-value 0.019), shorter PSG and MSLT sleep latency (p-value 0.037, 0.004), shorter MSLT REM sleep latency (p-value<0.001) and higher total MSLT sleep onset REM periods (p-value 0.040). An RSWA cut-off ≥ 2.8% predicted dream enactment in NT1 and NT2 with AUC = 0.81 with sensitivity of 77% and specificity of 85%.

Conclusions RSWA quantity is highest in NT1, intermediate in NT2, and lowest in IH and may serve as an adjunct PSG marker of narcolepsy.

Authors/Disclosures
Sikawat Thanaviratananich, MD (Case Western Reserve University) PRESENTER	Dr. Thanaviratananich has nothing to disclose.
Delaney Ryan, MPH	Miss Ryan has nothing to disclose.
James Bena, MS	Mr. Bena has nothing to disclose.
Jad El Ahdab, MD	Dr. El Ahdab has nothing to disclose.
Nancy R. Foldvary-Schaefer, DO, FAAN (Cleveland Clinic)	Dr. Foldvary-Schaefer has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Jazz. The institution of Dr. Foldvary-Schaefer has received research support from Jazz. The institution of Dr. Foldvary-Schaefer has received research support from Suven. The institution of Dr. Foldvary-Schaefer has received research support from Takeda. Dr. Foldvary-Schaefer has received publishing royalties from a publication relating to health care. Dr. Foldvary-Schaefer has received publishing royalties from a publication relating to health care.

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