Abstract Details

Title Diagnostic Thresholds for REM Sleep Without Atonia in Idiopathic/Isolated REM Sleep Behavior Disorder in the North American Prodromal Synucleinopathy (NAPS) Cohort

Topic Sleep

Presentation(s) Sleep Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 024

Background iRBD is a prodromal alpha-synucleinopathy characterized by dream enactment behavior and RSWA. We sought to define quantitative RSWA diagnostic thresholds in the North American Prodromal Synucleinopathy (NAPS) Consortium cohort.

Objective We analyzed REM sleep without atonia (RSWA) between idiopathic/isolated REM sleep behavior disorder (iRBD) patients across participating NAPS sleep centers, compared to normative controls, and hypothesized that previous diagnostic RSWA thresholds were overestimates.

Design/Methods All digital polysomnography files were converted to European Data Format and scored at a central laboratory (Mayo Clinic) which standardized display scoring montages, channel sensitivities, and filtering, and scripted computational analyses for visual scoring. RSWA was quantitatively analyzed in the submentalis (SM) and anterior tibialis (AT) muscles in iRBD (n=86) patients and controls (n=118) utilizing well validated visual (Mayo) and automated (RAI) methods. Parametric statistics were used to compare RSWA metrics, and RSWA thresholds were developed using receiver operating characteristic curves.

Results RSWA was significantly higher for the RAI and all visual individual and combined muscle activity metrics in iRBD compared to controls (all p<0.001). Average SM phasic measures were: 14.2% (Mayo), 17.9% (McGill), 18.5% (UCLA), and 9.4% (Washington University). Average AT phasic measures at each site were: 26.7% (Mayo), 17.1% (McGill), 23.3% (UCLA), and 17.4% (Washington University). Average SM/AT ‘any’ measures at each site were: 45.4% (Mayo), 35.9% (McGill), 53.4% (UCLA), and 23.5% (Washington University). Overall cohort RBD diagnostic thresholds (AUC, specificity/sensitivity) were: SM phasic 4.9% (90.0, 82.2%/83.7%); AT phasic 7.6% (88.7%, 82.2%/81.4%) and combined SM/AT ‘any’ 13% (94.6, 83.9%/96.5%).

Conclusions RSWA thresholds in the NAPS cohort were substantially lower than previously reported, suggesting previously overestimated diagnostic RSWA thresholds due to smaller, enriched patient samples and overfit statistical modeling. Confirmation of these findings in the complete NAPS cohort (n=300 iRBD patients across all 10 NAPS centers) is planned.

Authors/Disclosures
John C. Feemster, MD (Johns Hopkins Hospital) PRESENTER	Mr. Feemster has nothing to disclose.
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Stuart McCarter, MD (Mayo Clinic)	Dr. McCarter has received research support from NIH.
Bradley F. Boeve, MD, FAAN (Mayo Clinic)	Dr. Boeve has received personal compensation in the range of $10,000-$49,999 for serving as an officer or member of the Board of Directors for Rainwater Charitable Foundation. The institution of Dr. Boeve has received research support from Alector. The institution of Dr. Boeve has received research support from EIP Pharma. The institution of Dr. Boeve has received research support from Transposon. The institution of Dr. Boeve has received research support from Cognition Therapeutics. Dr. Boeve has received publishing royalties from a publication relating to health care.
	No disclosure on file
Yo-El Ju, MD	The institution of Dr. Ju has received research support from National Institutes of Health.
Jennifer S. McLeland (Washington University School of Medicine)	Ms. McLeland has nothing to disclose.
Ronald Postuma, MD (Montreal General Hospital)	Dr. Postuma has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Roche, Biogen, Takeda, Theranexus, GE, Jazz, Curasen, Paladin, Inception Sciences, Phytopharmics, Vaxxinity, Merck. Dr. Postuma has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen/Partners. The institution of Dr. Postuma has received research support from CIHR, Weston Foundation, Webster Foundation, Roche, MJFF, Parkinson Canada, FRSQ, NIH.
Amelie Pelletier (Montreal General Hospital)	Ms. Pelletier has nothing to disclose.
Alon Y. Avidan, MD, MPH, FAAN (David Geffen School of Medicine at UCLA)	Dr. Avidan has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Eisai. Dr. Avidan has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Avadel. Dr. Avidan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Harmony. Dr. Avidan has received personal compensation in the range of $0-$499 for serving as a Consultant for Merck. Dr. Avidan has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Eisai. Dr. Avidan has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Harmony. Dr. Avidan has received publishing royalties from a publication relating to health care.
	No disclosure on file
	No disclosure on file
Erik K. St. Louis, MD (Mayo Clinic)	Dr. St. Louis has received publishing royalties from a publication relating to health care. Dr. St. Louis has received publishing royalties from a publication relating to health care.