0651 REM Sleep Without Atonia (RSWA) And Neuropsychological Function In REM Sleep Behavior Disorder

Introduction REM sleep Behavior Disorder (RBD) is a parasomnia characterized by the presence of REM Sleep Without Atonia (RSWA) resulting in abnormal and violent behaviors. Evidence from literature demonstrates that Isolated RBD (IRBD) is a prodromal phase of neurodegenerative diseases with high conversion rates in synucleinopathies. The aim of the study is to investigate the relationship between cognitive impairment and RSWA in IRBD patients. Methods 35 IRBD patients and 18 healthy controls (HC) were recruited, underwent a complete polysomnography (PSG) as well as a comprehensive neuropsychological evaluation. Moreover, IRBD patients were divided into two groups based on the presence or absence of Mild Cognitive Impairment (MCI). The PSG were analyzed by a scorer, blind to subjects’ diagnosis, to quantify the RSWA of six different indices of muscle activity extracted by phasic and tonic events recorded in different time series (miniepochs of 2 or 3 seconds, or epochs of 30 seconds) and muscle combinations (flexor digitorum superficialis, mentalis and tibialis muscles). Results Comparative analyses showed that the percentages of RSWA were significantly higher in the IRBD group than HC. The best discriminative power was obtained by the combination of phasic and tonic events recorded in micro epochs of 3 seconds from the mentalis muscle and flexor digitorum superficialis (IRBD 0.787 ±0.195, HC 0.306±0.183, p