Short‐interval leg movements during sleep entail greater cardiac activation than periodic leg movements during sleep in restless legs syndrome patients

Abstract

Periodic leg movements during sleep (PLMS) are sequences of ≥4 motor events with intermovement intervals (IMI) of 10-90 s. PLMS are a supportive diagnostic criterion for restless legs syndrome (RLS) and entail cardiac activation, particularly when associated with arousal. RLS patients also over-express short-interval leg movements during sleep (SILMS), which have IMI <10 s and are organized mainly in sequences of two movements (doublets). We tested whether the cardiac activation associated with SILMS doublets differs from that associated with PLMS in a sample of 25 RLS patients. We analysed time-series of R-R intervals synchronized to the onset of SILMS doublets or PLMS that entailed an arousal during non-rapid eye movement (NREM) sleep. We assessed cardiac activation based on the R-R interval decrease with respect to baseline during NREM sleep without leg movements. We found that the duration of the R-R interval decrease with SILMS doublets was significantly longer than that with PLMS, whereas the maximal decrease in R-R interval was similar. Scoring SILMS in RLS patients may therefore be relevant from a cardiac autonomic perspective.

Peculiar lifespan changes of periodic leg movements during sleep in restless legs syndrome

“…The increase of SILMS in the seniors may be linked to the lower sleep depth and increase in arousals that characterize this age period. Accordingly, SILMS have already been shown to be most evident during wakefulness, especially in patients with RLS (Ferri et al., , 2015b), and their importance in this context is due to the fact that they might represent an even higher risk than PLMS for cerebro‐ and cardiovascular consequences because they are accompanied by more sustained cardiac activations (Ferri et al., 2017b).…”

“…Dopamine agonists are certainly not the first‐line approach for RLS or PLMD in children (Rulong, Dye, & Simakajornboon, ) and studies supporting their use are scarce and report doubtful results (England et al., ). In addition, our findings indicate clearly that at all ages it is also important to evaluate the number of LM activities that differ from PLMS (SILMS and ILMS) because, together, they can reach important numbers and are accompanied by cardiac activations more evident than those accompanying PLMS (Ferri et al., , 2017b).…”

Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome

“…Adult patients with RLS typically show an increased occurrence rate not only of PLMS, but also of all leg movements during sleep (LMS) compared to control subjects (Ferri et al, 2017a). The short-interval LMS with inter-movement interval between 0.5 and 10 s entail greater accompanying changes in heart rate compared with PLMS (Ferri et al, 2017b). Short-interval LMS also occur in healthy human subjects, albeit at a much lower rate than in patients with RLS (Ferri et al, 2017a), as well as in healthy rats and mice (Silvani et al, 2015).…”

Cardiac Activation Associated with Non-Periodic Leg Movements in Comparison to Periodic Leg Movements during Sleep in Patients with Restless Legs Syndrome and Healthy Subjects

“…3), which is consistent with previous studies. 5,9 In patients with RLS, heart rate change in relation to LM is significantly different by LM types. SILMS are accompanied with the greatest and the longest increase in heart rate change while PLMS are associated with the lowest and the shortest heart rate change.…”

“…SILMS during non-rapid eye movement (NREM) sleep that were associated with arousal and a sequence of two LM (doublet) had a similar peak cardiac activation as that associated with PLMS, but had a significantly longer duration. 9 Cardiac activation related to ILMS compared to that related to PLMS had conflicting results. In the study by Ferri et al, heart rate elevations seen with ILMS are higher than those seen with PLMS, 5 while heart rate elevations with PLMS were higher than those with ILMS in the study by Guggisberg et al 10 Therefore, understanding the relationships between NPLM and heart rate and EEG arousal has important implications for evaluating the risks associated with cardiovascular disease in patients with RLS.…”