[Heart rate variability during sleep in children with multiple disabilities]

To study heart rate variability during sleep in children with multiple disabilities in order to observe the behavior of the autonomic nervous system.

The R-R interval variability of 4 to 12 years old children was recorded with a heart rate monitor during one night. Children with multiple disabilities (G1) and healthy children (G2) were compared in time, frequency, and non-linear domains.

Temporal (P<0.01), frequency (P<0.05), and non-linear (P<0.01) variables in the G1 were lower than in the G2 group.

The time and frequency analysis confirmed the predominance of the sympathetic nervous system during sleep in G1 children. Reduced non-linear variables can explain sleep with less informations (correlation dimension: 2.203 ± 1.239 versus 3.842 ± 0.378; P<0.001), less complex cycles of sleep (approximate entropy: 1.153 ± 0.200 versus 1.365 ± 0.099; P<0.01), and a reduced correlation in short-term variability (SD1: 42.37 ± 19.0 (ms) versus 73.44 ± 25.3; P<0.01). The fractal structure of the recordings was not affected (P>0.05). The diseases encountered are probably the reason for these findings, but the variety of disorders and medications of the children with multiple disabilities needs to be studied with a larger and more varied sample.

Sympathetic predominance during sleep in children with multiple disabilities is associated with a decrease in adaptive abilities of these children's autonomic nervous system.