REM Sleep without Atonia Severity Predicts Cognitive Impairment in REM Sleep Behavior Disorder (P7.307)

Abstract

OBJECTIVE: We investigated whether REM sleep without atonia (RSWA) severity was associated with cognitive functioning in REM sleep behavior disorder (RBD). BACKGROUND: RBD is a potentially injurious parasomnia that is strongly associated with synucleinopathy. Patients with RBD exhibit RSWA, the loss of normal muscle atonia during REM sleep, on polysomnography (PSG). DESIGN/METHODS: Both idiopathic (iRBD) and symptomatic RBD (sRBD) patients completed two cognitive batteries: CNS Vital Signs (CNS-VS) and Useful Field of View (UFOV). All subjects underwent PSG and muscle (SM: submentalis; AT: anterior tibialis) tone during REM sleep was visually and automatically scored. Group differences between sRBD and iRBD were then compared, and regression models fit to determine the relationship of RSWA and dependent cognitive measures. RESULTS: Twenty iRBD and 10 sRBD participated. Demographics were similar between groups. Deficits on cognitive testing were observed on CNS-VS in processing (sRBD<iRBD, p=0.014) and psychomotor speed (sRDB<iRBD, p=0.019) and on Total UFOV and subtests 2 and 3 (sRBD>iRBD, all p<0.002). sRBD patients had greater combined phasic and tonic RSWA in SM (p=0.026) and longer mean phasic burst duration (p=0.03). Regression analyses demonstrated that SM RSWA independently predicted overall CNS-VS Neurocognitive Index (NCI) (F=4.5, p=0.006), adjusting for age, gender, depressive symptoms (Zung Score), and sleep disturbances (PSQI), and this relationship also remained significant for the iRBD group after excluding sRBD patients from analysis to account for the effect of co-morbid neurologic or cognitive disorders (F=3.5, p=0.03). SM RSWA was not predictive of total UFOV performance. CONCLUSIONS: RSWA is predictive of lower overall cognitive performance in patients with RBD. Future prospective analysis of a larger cohort is planned to determine whether RSWA may also predict other neurological signs of phenoconversion to overt synucleinopathy in iRBD patients. Study Supported by: UL1 RR024150-01.

Disclosure: Dr. Sandness has nothing to disclose. Dr. St. Louis has received personal compensation for activities with Inspire, Inc. Dr. McCarter has nothing to disclose. Dr. Boeve has received research support from GE Healthcare. Dr. Silber has nothing to disclose.