0928 Heart Rate Variability During Sleep in Children and Adolescents with Restless Sleep Disorder or Restless Legs Syndrome and Normal Controls

Introduction Restless sleep disorder (RSD) has been recently characterized clinically and polysomnographically in children and differentiated from restless legs syndrome (RLS). Heart rate variability (HRV) is a reliable method to quantify autonomic changes during sleep. The aim of this study was to characterize HRV in children with RSD, RLS and normal controls, with the hypothesis that children with RSD have a shift toward sympathetic predominance during sleep. Methods Polysomnographic recordings from thirty-two children who fulfilled RSD diagnostic criteria (19 boys and 13 girls), 32 children with RLS (20 boys and 12 girls) and 33 controls (17 boys and 16 girls) were included. Four ECG epochs were chosen, one for each stage, and were analyzed for automatic detection of R waves. Time domain and frequency domain HRV parameters were obtained and analyzed. Results Age and gender were not statistically different between groups. In terms of time domain only the standard deviation of the average RR interval during stage N3 was slightly but significantly higher in RSD than in RLS patients. In terms of frequency domains, the LF band and the LF/HF ratio were increased in RSD and the HF percentage was lower in RSD during sleep stages N3 and R. The LF band and the LF/HF ratio increased in RLS and the HF percentage was lower in RLS during stage W. Conclusion Children with RSD have increased sympathetic activation during sleep, particularly N3 and REM, compared to controls but, as expected, not during wakefulness. Differently, children with RLS have sympathetic activation during relaxed wakefulness preceding sleep and during sleep. Support Partial support by a grant of the Italian Ministry of Health RC n. 2751598 (R.F.)