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Introduction: Parkinson’s Disease (PD), a common neurodegenerative disease worldwide, has few reliable biomarkers. PD has been linked to REM Behavioral Disorder (RBD), a condition where patients abnormally experience REM sleep without atonia (RSWA). We aim to determine whether chin movements, a feature of RSWA, could serve as a PD biomarker. We hypothesize that those with higher RSWA are more likely to have PD.

Methods: Our study examined patients who underwent polysomnograms from 2015 onwards at the Jefferson Sleep Disorders Center. We did a retrospective EPIC chart review and compared 2 groups, those with RBD and PD (n=12) versus RBD alone (n=25). While examining their polysomnographic data, %RSWA was calculated using AASM guidelines. Recursive partitioning algorithm was used to determine the %RSWA that correlated with the presence or absence of PD.

Results: Patients with higher %RSWA were more likely to have PD as shown by the following data. RSWA >20% was present in 11 patients, and had the highest correlation with PD (9/11). RSWA of 2.1% to 19.9% was present in 10 patients, and had modest correlation with PD (3/10). RSWA <2.1% was present in 15 patients, and had the least correlation with PD (0/15).

Discussion: Our results support our hypothesis indicating that RSWA, specifically chin movements, in RBD patients could serve as a PD biomarker. A larger cohort would need to be examined, however, this introduces the idea of routinely screening RBD patients for this and subsequently monitoring for PD symptoms. This could lead to earlier diagnosis and better prognosis.