2026 American Academy of Neurology Abstract Website

Neha Reddy¹, Yuzheng Nie³, Hernis De La Cruz³, Chengjie Xiong³, Alon Avidan⁴, Don Bliwise⁵, Meghan Campbell⁶, Susan Criswell⁷, Albert Davis⁷, Kevin Duff⁸, Jonathan Elliott⁸, Tanis Ferman⁹, Leah Forsberg², Jean-Francois Gagnon¹⁰, Michael Howell¹¹, Daniel Huddleston¹², Miranda Lim¹³, Jessica Locke¹⁴, Jennifer McLeland³, Mitchell Miglis¹⁵, Toji Miyagawa², Lee Neilson⁸, Kendall Nichols¹², Amelie Pelletier¹⁶, Carlos Schenck¹⁷, Erik St. Louis², Oliver Sum-Ping¹⁸, LynnMarie Trotti¹⁹, Aleksandar Videnovic²⁰, Ronald Postuma¹⁶, Yo-El Ju³, Julie Fields², Bradley Boeve², Stuart McCarter²
¹Department of Neurology, Mayo Clinic, ²Mayo Clinic, ³Washington University School of Medicine, ⁴David Geffen School of Medicine at UCLA, ⁵Emory School of Medicine, ⁶Washington University in St. Louis, ⁷Washington University, ⁸Oregon Health & Science University, ⁹Mayo Clinic Jacksonville, ¹⁰Centre D'etude Du Sommeil, ¹¹University of Minnesota, ¹²Emory University, ¹³VA Portland Health Care System, ¹⁴OHSU Neurology, ¹⁵Stanford University Medical Center, ¹⁶Montreal General Hospital, ¹⁷Minnesota Regional Sleep Disorders Center, ¹⁸Stanford University, ¹⁹Emory University School of Medicine, ²⁰MGH Neurological Clinical Research Institute

Objective:

To compare self-reported and objective symptoms of motor and non-motor dysfunction in isolated RBD (iRBD) patients with subjective cognitive impairment (iRBD-SCI), quantitative cognitive impairment (iRBD-QCI), and no cognitive impairment (iRBD).

Background:

iRBD patients frequently endorse motor and non-motor symptoms without clear objective correlations. Comparisons between subjective motor or non-motor symptoms and objective measures have not been explicitly evaluated in iRBD.

Design/Methods:

Participants included 268 iRBD, 60 iRBD-SCI and 44 iRBD-QCI from the North American Prodromal Synucleinopathy (NAPS) cohort. iRBD patients had no cognitive complaints, with normal neuropsychological testing; iRBD-SCI had cognitive complaints with normal neuropsychological testing; and iRBD-QCI had no cognitive complaints but abnormal neuropsychological testing. Non-motor symptoms were measured by MDS-UPDRS-I. Subjective and objective motor symptoms were measured by MDS-UPDRS-II and MDS-UPDRS-III, respectively. Subjective autonomic symptoms were assessed with SCOPA-AUT and objective autonomic dysfunction by orthostatic blood pressure drop. Total symptom burden was assessed with the Prodromal Synucleinopathy Rating Scale sum score (PSRS SUM). One-way ANOVA with Tukey’s HSD post-hoc tests determined significant group differences.

Results:

iRBD-SCI scored higher on MDS-UPDRS-I than both iRBD-QCI (4.1; 95% CI 1.1–7.0) and iRBD (2.4; 95% CI 0.3–4.5). iRBD-SCI had higher MDS-UPDRS-II than iRBD-QCI (2.7; 95% CI 0.2–5.3), with no differences in objective motor measures. SCOPA-AUT was higher in iRBD-SCI than both iRBD-QCI (5.0; 95% CI 1.5–8.4) and iRBD (3.1; 95% CI 0.6–5.6), with no differences in orthostatic blood pressure drop between groups. iRBD-SCI scored higher on PSRS SUM than iRBD-QCI (3.7; 95% CI 1.5–5.8) and iRBD (2.4; 95% CI 0.9–3.9). iRBD and iRBD-QCI did not differ on any measure.

Conclusions:

iRBD-SCI endorse greater subjective motor and non-motor symptomatology than both iRBD-QCI and iRBD patients without differences in objective motor or autonomic functioning. Longitudinal follow-up will be necessary to assess phenoconversion differences between groups.