Autonomic correlates of large muscle group movements during non-REM sleep in restless legs syndrome: a comparative analysis with periodic and non-periodic leg movements

LMMS are associated with strong autonomic activation indicating parasympathetic withdrawal and/or sympathetic activation, distinguishing them from other sleep-related leg movements in RLS. The absence of post-peak bradycardia suggests reduced parasympathetic buffering, potentially reflecting more sustained arousal mechanisms. Statement of Significance This study provides the first detailed characterization of the heart rate dynamics associated with large muscle group movements during sleep (LMMS) in patients with restless legs syndrome (RLS). By comparing LMMS with established motor patterns such as periodic, isolated, and short-interval leg movements during sleep, we show that LMMS induce the strongest and most sustained autonomic responses. These responses are likely driven by sympathetic activation and/or parasympathetic withdrawal due to sustained arousal-related central autonomic commands. These findings support the hypothesis that LMMS represent a physiologically distinct class of sleep-related motor events with unique implications for cardiovascular and sleep disruption risk in RLS.